The document summarizes a study that measured and compared the flexural strength of 10 veneering ceramics for zirconia frameworks and 3 veneering ceramics for metal-ceramic restorations. Three types of flexural strength tests were used: three-point flexure, four-point flexure, and biaxial flexure. For the zirconia ceramics, three-point flexure strengths were similar without differences, four-point flexure identified 5 strength groups, and biaxial flexure found 3 groups. One metal-ceramic ceramic had significantly higher strengths than all others. Four-point flexure showed the greatest discrimination between materials. In general,
The document describes a procedure to determine the flexural strength or modulus of rupture of concrete through third-point loading tests. Steel molds are used to cast concrete prism specimens of either 100x100x500mm or 150x150x700mm size, depending on the maximum aggregate size. The specimens are loaded in a testing machine with rollers spaced at either 200mm or 133mm until failure. The maximum load at failure is then used to calculate the modulus of rupture according to one of two equations depending on the distance between the line of fracture and the near support.
This document provides the procedure for conducting a bend test on metallic materials. It specifies the test equipment, test pieces, and testing methods. The bend test involves bending a test piece to a specified angle or achieving parallelism of the legs. It can be done using supports and a mandrel, a V-block and mandrel, or a clamp. The test piece dimensions depend on the material thickness and width. The test is generally done at room temperature and the bent piece is examined to evaluate the material's ability to undergo plastic deformation during bending.
To determine the ductility of mild steel specimens using a three-point bend test. The test involves placing steel bar specimens on a bend test machine with supports 8 times the bar diameter apart and a handle 5 times the bar diameter above the supports. A load is applied until the bar bends at 180 degrees, though some spring back was observed. No cracks were observed, indicating the material is suitable for use. The three-point bend test provides a simple way to evaluate materials' ability to resist cracking during bending.
This document summarizes a lecture on compression testing. It discusses how compression tests are used to determine material properties like compressive strength and modulus of elasticity. The test involves placing a sample in a universal testing machine and applying a compressive load until failure. Common applications include the aerospace, automotive, and construction industries. While easier than tension tests, compression tests can be impacted by friction, eccentric loading, and buckling of the sample. The document outlines best practices for sample geometry and preparation to minimize these issues and get accurate results.
This document describes the procedure for conducting a tensile test to determine the tensile splitting strength of a material according to BS 1881 standards. Specimens are placed between hardboard packing strips and steel loading pieces and loaded continuously in a testing machine until failure. The tensile splitting strength is calculated using the maximum load at failure, specimen dimensions, and material density.
This document discusses flexural strength testing of materials. Flexural strength refers to a material's ability to resist deformation when bent or flexed. The flexural strength test involves placing a specimen on supports and applying a load at the center or at third points until failure. The flexural strength or modulus of rupture is calculated based on the maximum load at failure, and the dimensions and span of the specimen. Proper apparatus, loading rates, and procedures are required to accurately determine the flexural strength. Test results should report key details like specimen information, loading conditions, and failure mode.
This document provides the standard test method for determining the splitting tensile strength of cylindrical concrete specimens. It describes the procedure which involves applying a diametral compressive force along the length of a concrete cylinder at a controlled rate until failure. The maximum load sustained is used to calculate the splitting tensile strength in psi. Proper specimen preparation, loading rate, and calculations are specified to provide consistent results.
It is a motorized, mechanical unit. The speed is adjusted so that the load increase on the specimen is between 4 to 6 kg/sec. A flexure test attachment for keeping the object in position is also supplied. This consists of two rollers 10mm. diameter and spaced 100mm apart, and a third roller of the same diameter equidistant from the first two and for transmitting the applied load to the opposite face of the prism.
The document describes a procedure to determine the flexural strength or modulus of rupture of concrete through third-point loading tests. Steel molds are used to cast concrete prism specimens of either 100x100x500mm or 150x150x700mm size, depending on the maximum aggregate size. The specimens are loaded in a testing machine with rollers spaced at either 200mm or 133mm until failure. The maximum load at failure is then used to calculate the modulus of rupture according to one of two equations depending on the distance between the line of fracture and the near support.
This document provides the procedure for conducting a bend test on metallic materials. It specifies the test equipment, test pieces, and testing methods. The bend test involves bending a test piece to a specified angle or achieving parallelism of the legs. It can be done using supports and a mandrel, a V-block and mandrel, or a clamp. The test piece dimensions depend on the material thickness and width. The test is generally done at room temperature and the bent piece is examined to evaluate the material's ability to undergo plastic deformation during bending.
To determine the ductility of mild steel specimens using a three-point bend test. The test involves placing steel bar specimens on a bend test machine with supports 8 times the bar diameter apart and a handle 5 times the bar diameter above the supports. A load is applied until the bar bends at 180 degrees, though some spring back was observed. No cracks were observed, indicating the material is suitable for use. The three-point bend test provides a simple way to evaluate materials' ability to resist cracking during bending.
This document summarizes a lecture on compression testing. It discusses how compression tests are used to determine material properties like compressive strength and modulus of elasticity. The test involves placing a sample in a universal testing machine and applying a compressive load until failure. Common applications include the aerospace, automotive, and construction industries. While easier than tension tests, compression tests can be impacted by friction, eccentric loading, and buckling of the sample. The document outlines best practices for sample geometry and preparation to minimize these issues and get accurate results.
This document describes the procedure for conducting a tensile test to determine the tensile splitting strength of a material according to BS 1881 standards. Specimens are placed between hardboard packing strips and steel loading pieces and loaded continuously in a testing machine until failure. The tensile splitting strength is calculated using the maximum load at failure, specimen dimensions, and material density.
This document discusses flexural strength testing of materials. Flexural strength refers to a material's ability to resist deformation when bent or flexed. The flexural strength test involves placing a specimen on supports and applying a load at the center or at third points until failure. The flexural strength or modulus of rupture is calculated based on the maximum load at failure, and the dimensions and span of the specimen. Proper apparatus, loading rates, and procedures are required to accurately determine the flexural strength. Test results should report key details like specimen information, loading conditions, and failure mode.
This document provides the standard test method for determining the splitting tensile strength of cylindrical concrete specimens. It describes the procedure which involves applying a diametral compressive force along the length of a concrete cylinder at a controlled rate until failure. The maximum load sustained is used to calculate the splitting tensile strength in psi. Proper specimen preparation, loading rate, and calculations are specified to provide consistent results.
It is a motorized, mechanical unit. The speed is adjusted so that the load increase on the specimen is between 4 to 6 kg/sec. A flexure test attachment for keeping the object in position is also supplied. This consists of two rollers 10mm. diameter and spaced 100mm apart, and a third roller of the same diameter equidistant from the first two and for transmitting the applied load to the opposite face of the prism.
- The document describes test methods for compression testing of metallic materials at room temperature. It covers the apparatus, specimens, and procedures used.
- Specimens are subjected to increasing axial compressive loads while load and strain are monitored. This determines properties like yield strength and compressive strength.
- Proper specimen preparation and qualified testing equipment are required to prevent issues like buckling and get accurate results. Specimen dimensions and testing procedures are specified.
The document provides information on Indian Standard IS 5816:1999 which outlines the procedure for determining the splitting tensile strength of concrete cubes and cylinders. It describes the test specimens, apparatus, procedure, calculations, and reporting requirements. Key points include:
- The standard covers testing of concrete cubes and cylinders to determine splitting tensile strength.
- Specimens must be at least 150mm in size and cured for 24 hours before testing.
- A compression testing machine is used to apply a continuous, increasing load to the center of the specimen until failure.
- Splitting tensile strength is calculated based on the maximum load at failure and dimensions of the specimen.
- Test results should include specimen details, age,
This document discusses the split tensile strength test for concrete. It begins by explaining that the split tensile strength test is an indirect method for determining the tensile strength of concrete using cylindrical specimens. It then describes the procedure for the test, which involves placing a cylinder between loading plates and applying an increasing load until failure. The maximum load at failure is used to calculate the splitting tensile strength of the concrete. The document provides details on specimen preparation, curing, testing apparatus, and calculations.
This document describes bend testing procedures for evaluating the ductility of welds. It discusses different types of bend tests including guided bend tests, where a mandrel forces the specimen between supports, and free bend tests. It explains that guided bend tests are primarily used for plates. The document also outlines how to prepare bend test samples in different orientations like transverse face, root, and side bends as well as longitudinal face and root bends. Finally, it states that bend testing can show the tensile strength, ductility, and fusion/penetration of welds.
Tensile, Impact and Hardness Testing of Mild SteelGulfam Hussain
The main purpose of this report is to study the mechanical properties and
failure mode of mild steel. Three types of standard tests i.e. tensile test, impact
test, and hardness test were conducted on the standard specimens of mild steel.
From the tests, results were obtained; Tensile strength, Impact strength, and
hardness were calculated. It was observed that Tensile Strength, Impact Strength
and Hardness of MS specimen were 1450.833 N/mm², 29.5 J & 59.25 HRB.
This document describes a test to determine the split tensile strength of concrete cylinders. The test involves placing a concrete cylinder between the platens of a compression testing machine and applying a diametric load until the cylinder splits. The maximum load at failure is used to calculate the splitting tensile strength of the concrete according to the formula provided. The test is conducted according to IS 5816-1970 on cylinders that are 15cm in diameter and 30cm in height after a 28 day curing period.
This document discusses different methods for measuring hardness in materials:
1. The Rockwell hardness test uses a diamond or steel ball indenter that is pressed into the material under a minor and then major load. The permanent increase in depth from the major load is used to calculate the Rockwell hardness number.
2. The Brinell hardness test uses a 10mm steel or carbide ball pressed into the material under a 3000kg load. The diameter of the indentation is measured to calculate the Brinell hardness number.
3. The Vickers hardness test uses a diamond pyramid indenter pressed into the material. The average of the diagonal lengths of the resulting indentation is used to calculate the Vickers hardness number.
Experiment NO:6 describes a compression test performed on an anisotropic wooden material to determine its compressive strength when force is applied both parallel and perpendicular to its fibers. When force was applied perpendicular to the fibers, the wooden block failed at a compressive strength of 4.7712x107 N/m2. When applied parallel to the fibers, the failure strength was lower at 1.204x107 N/m2. Detailed load-deformation data is provided in tables showing that the material can withstand over 10 times more load when compressed parallel rather than perpendicular to its fibers, as the fibers act like columns parallel to the load.
This document discusses the 3-point flexural test, which measures the flexural properties of materials. In a 3-point flexural test, a specimen is placed on two supporting pins and a loading pin is applied in the middle. Calculations are performed to determine flexural stress, strain, and modulus based on the load and deflection measurements. The test provides values for modulus of elasticity in bending, flexural stress, flexural strain, and flexural stress-strain response. It is a common test for evaluating a material's stiffness when flexed.
1. The beam is a cantilever 1.2 m long made of steel tube with an external diameter of 6 cm and internal diameter of 5 cm.
2. A concentrated load W is applied at the free end of the cantilever beam.
3. The maximum bending stress in the beam is not to exceed 1. The value of the load W that satisfies this condition is required.
The micro Vickers hardness test uses a diamond indenter with a 136-degree pyramid shape to make indentations on a material under precise loads. The load is applied for 10-15 seconds, leaving a square-shaped impression. The two diagonals of the impression are measured under a microscope and used to calculate the Vickers hardness value according to the formula HV = 1.8544F/d^2, where F is the applied force in gf and d is the average diagonal length in mm. This test method can precisely test small parts, thin materials, and layers due to the small indenter size and indentations produced.
In the material testing laboratory, a Charpy impact test was performed on three different types (hot,cold,and steel alloy)of steels testing each variety at four different temperatures (32°C(RT), 100°C,0°C and -22°C ). From results (shown below), we determined that the a transition is from ductile failures to brittle failures
This presentation is for mechanical engineering/ civil engineering students to help them understand the different type of destructive mechanical testing of materials. The tensile testing, hardness, impact test procedures are explained in detail.
This document describes procedures for direct shear testing to determine a material's shear strength. Direct shear testing aims to simulate uniform shear stress across a specimen's cross-section by applying shear forces over small lengths to minimize bending. There are two types of direct shear tests: single shear tests shear across a single surface, while double shear tests shear across two surfaces. The test procedure involves fixing a cylindrical specimen in a shear tool and applying a compressive or tensile load until fracture, then calculating the shear strength from the maximum load and specimen's cross-sectional area.
Impact strength refers to a concrete's ability to resist sudden shock or load. It is important for applications with potential impact loads. There is no direct relationship between impact and compressive strength. Impact strength depends on factors like the aggregate type, size, and roughness, as well as the concrete's flexural strength and storage conditions. Non-destructive tests like the Schmidt hammer and ultrasonic pulse velocity test can provide indications of a concrete's properties, including compressive strength. The Schmidt hammer measures surface hardness while ultrasonic pulse velocity relies on sound waves to determine properties related to density and elasticity.
This lab report details procedures for determining the uniaxial compressive strength of rocks and concrete using Schmidt rebound hammers. Rebound hammers measure the elastic properties of materials by striking a spring-driven pin and measuring its rebound. Readings are used to estimate compressive strength by referencing conversion tables. Tests found that a quartzite rock sample had poor quality based on a rebound number equivalent to 41MPa of compressive strength, while a concrete sample had a good quality layer with a rebound number of 43MPa.
Tensile testing is a fundamental materials science test in which a sample is subjected to a controlled tension until failure.
This test is mainly used to select a material for an application, for quality control, and to predict how a material will react under other types of forces.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
This document describes the design of a 3-point bending device to measure beam deflection. Several proposed solutions were considered, including a computerized model and design with fixed supports and movable load hook. However, these had issues like complexity, inability to measure at the load point, and reaction forces acting on a circular not point surface. The final design uses knife-edge supports and a different load application method. Testing involved applying fixed loads at different positions and measuring deflection to study beam behavior and determine material properties. Practical problems in implementation included orienting the knife edges perpendicular to the beam and support tip accuracy.
- The document describes test methods for compression testing of metallic materials at room temperature. It covers the apparatus, specimens, and procedures used.
- Specimens are subjected to increasing axial compressive loads while load and strain are monitored. This determines properties like yield strength and compressive strength.
- Proper specimen preparation and qualified testing equipment are required to prevent issues like buckling and get accurate results. Specimen dimensions and testing procedures are specified.
The document provides information on Indian Standard IS 5816:1999 which outlines the procedure for determining the splitting tensile strength of concrete cubes and cylinders. It describes the test specimens, apparatus, procedure, calculations, and reporting requirements. Key points include:
- The standard covers testing of concrete cubes and cylinders to determine splitting tensile strength.
- Specimens must be at least 150mm in size and cured for 24 hours before testing.
- A compression testing machine is used to apply a continuous, increasing load to the center of the specimen until failure.
- Splitting tensile strength is calculated based on the maximum load at failure and dimensions of the specimen.
- Test results should include specimen details, age,
This document discusses the split tensile strength test for concrete. It begins by explaining that the split tensile strength test is an indirect method for determining the tensile strength of concrete using cylindrical specimens. It then describes the procedure for the test, which involves placing a cylinder between loading plates and applying an increasing load until failure. The maximum load at failure is used to calculate the splitting tensile strength of the concrete. The document provides details on specimen preparation, curing, testing apparatus, and calculations.
This document describes bend testing procedures for evaluating the ductility of welds. It discusses different types of bend tests including guided bend tests, where a mandrel forces the specimen between supports, and free bend tests. It explains that guided bend tests are primarily used for plates. The document also outlines how to prepare bend test samples in different orientations like transverse face, root, and side bends as well as longitudinal face and root bends. Finally, it states that bend testing can show the tensile strength, ductility, and fusion/penetration of welds.
Tensile, Impact and Hardness Testing of Mild SteelGulfam Hussain
The main purpose of this report is to study the mechanical properties and
failure mode of mild steel. Three types of standard tests i.e. tensile test, impact
test, and hardness test were conducted on the standard specimens of mild steel.
From the tests, results were obtained; Tensile strength, Impact strength, and
hardness were calculated. It was observed that Tensile Strength, Impact Strength
and Hardness of MS specimen were 1450.833 N/mm², 29.5 J & 59.25 HRB.
This document describes a test to determine the split tensile strength of concrete cylinders. The test involves placing a concrete cylinder between the platens of a compression testing machine and applying a diametric load until the cylinder splits. The maximum load at failure is used to calculate the splitting tensile strength of the concrete according to the formula provided. The test is conducted according to IS 5816-1970 on cylinders that are 15cm in diameter and 30cm in height after a 28 day curing period.
This document discusses different methods for measuring hardness in materials:
1. The Rockwell hardness test uses a diamond or steel ball indenter that is pressed into the material under a minor and then major load. The permanent increase in depth from the major load is used to calculate the Rockwell hardness number.
2. The Brinell hardness test uses a 10mm steel or carbide ball pressed into the material under a 3000kg load. The diameter of the indentation is measured to calculate the Brinell hardness number.
3. The Vickers hardness test uses a diamond pyramid indenter pressed into the material. The average of the diagonal lengths of the resulting indentation is used to calculate the Vickers hardness number.
Experiment NO:6 describes a compression test performed on an anisotropic wooden material to determine its compressive strength when force is applied both parallel and perpendicular to its fibers. When force was applied perpendicular to the fibers, the wooden block failed at a compressive strength of 4.7712x107 N/m2. When applied parallel to the fibers, the failure strength was lower at 1.204x107 N/m2. Detailed load-deformation data is provided in tables showing that the material can withstand over 10 times more load when compressed parallel rather than perpendicular to its fibers, as the fibers act like columns parallel to the load.
This document discusses the 3-point flexural test, which measures the flexural properties of materials. In a 3-point flexural test, a specimen is placed on two supporting pins and a loading pin is applied in the middle. Calculations are performed to determine flexural stress, strain, and modulus based on the load and deflection measurements. The test provides values for modulus of elasticity in bending, flexural stress, flexural strain, and flexural stress-strain response. It is a common test for evaluating a material's stiffness when flexed.
1. The beam is a cantilever 1.2 m long made of steel tube with an external diameter of 6 cm and internal diameter of 5 cm.
2. A concentrated load W is applied at the free end of the cantilever beam.
3. The maximum bending stress in the beam is not to exceed 1. The value of the load W that satisfies this condition is required.
The micro Vickers hardness test uses a diamond indenter with a 136-degree pyramid shape to make indentations on a material under precise loads. The load is applied for 10-15 seconds, leaving a square-shaped impression. The two diagonals of the impression are measured under a microscope and used to calculate the Vickers hardness value according to the formula HV = 1.8544F/d^2, where F is the applied force in gf and d is the average diagonal length in mm. This test method can precisely test small parts, thin materials, and layers due to the small indenter size and indentations produced.
In the material testing laboratory, a Charpy impact test was performed on three different types (hot,cold,and steel alloy)of steels testing each variety at four different temperatures (32°C(RT), 100°C,0°C and -22°C ). From results (shown below), we determined that the a transition is from ductile failures to brittle failures
This presentation is for mechanical engineering/ civil engineering students to help them understand the different type of destructive mechanical testing of materials. The tensile testing, hardness, impact test procedures are explained in detail.
This document describes procedures for direct shear testing to determine a material's shear strength. Direct shear testing aims to simulate uniform shear stress across a specimen's cross-section by applying shear forces over small lengths to minimize bending. There are two types of direct shear tests: single shear tests shear across a single surface, while double shear tests shear across two surfaces. The test procedure involves fixing a cylindrical specimen in a shear tool and applying a compressive or tensile load until fracture, then calculating the shear strength from the maximum load and specimen's cross-sectional area.
Impact strength refers to a concrete's ability to resist sudden shock or load. It is important for applications with potential impact loads. There is no direct relationship between impact and compressive strength. Impact strength depends on factors like the aggregate type, size, and roughness, as well as the concrete's flexural strength and storage conditions. Non-destructive tests like the Schmidt hammer and ultrasonic pulse velocity test can provide indications of a concrete's properties, including compressive strength. The Schmidt hammer measures surface hardness while ultrasonic pulse velocity relies on sound waves to determine properties related to density and elasticity.
This lab report details procedures for determining the uniaxial compressive strength of rocks and concrete using Schmidt rebound hammers. Rebound hammers measure the elastic properties of materials by striking a spring-driven pin and measuring its rebound. Readings are used to estimate compressive strength by referencing conversion tables. Tests found that a quartzite rock sample had poor quality based on a rebound number equivalent to 41MPa of compressive strength, while a concrete sample had a good quality layer with a rebound number of 43MPa.
Tensile testing is a fundamental materials science test in which a sample is subjected to a controlled tension until failure.
This test is mainly used to select a material for an application, for quality control, and to predict how a material will react under other types of forces.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
This document describes the design of a 3-point bending device to measure beam deflection. Several proposed solutions were considered, including a computerized model and design with fixed supports and movable load hook. However, these had issues like complexity, inability to measure at the load point, and reaction forces acting on a circular not point surface. The final design uses knife-edge supports and a different load application method. Testing involved applying fixed loads at different positions and measuring deflection to study beam behavior and determine material properties. Practical problems in implementation included orienting the knife edges perpendicular to the beam and support tip accuracy.
The document summarizes a study that investigated how adding glass flakes in concentrations of 5%, 10%, and 20% impacted the flexural and impact strength of denture base resins compared to an unmodified resin. Specimens were tested for flexural and impact strength based on ISO standards. Results showed flexural strength decreased with higher glass flake concentrations while impact strength was unchanged at 5% but decreased at 10% and 20%. The study concluded flexural and impact strength were lowest for the 20% glass flake modified resin group.
This document is a dissertation submitted by Varun Poddar for the degree of Master of Science in Bridge Engineering. It investigates the effect of reinforcement corrosion on the flexural strength of reinforced concrete beams. The dissertation begins with background on corrosion processes and mechanisms in reinforced concrete. It then discusses approaches to prevent corrosion and techniques for inspecting corrosion in structures. The document reviews empirical models for estimating the residual strength of corroded beams and presents a case study analyzing a corroded beam using finite element software ANSYS. The results from the ANSYS model are compared with empirical model predictions. While the models agree when not considering bond degradation, there are differences when bond degradation is included, possibly due to limitations in modeling spalling effects. Overall
Construction Materials Engineering and Testingmecocca5
This document provides an overview of materials testing services for soil, aggregate, concrete, and masonry. It describes common laboratory and field tests for evaluating the properties and quality of construction materials, including tests for soil particle size and compaction, concrete slump and strength, and masonry compressive strength. The document emphasizes that materials testing should be performed by properly trained personnel according to standardized test methods and that test results should be reported in a timely manner.
Prepared by madam rafia firdous. She is a lecturer and instructor in subject of Plain and Reinforcement concrete at University of South Asia LAHORE,PAKISTAN.
The document discusses heat cure acrylic denture base resins. It provides background on the development of denture base materials over time. Polymethyl methacrylate (PMMA) was introduced in 1937 and remains the material of choice due to its superior esthetics, ease of processing, accurate fit, and use with inexpensive equipment. The document describes the composition, chemical basis of polymerization, manipulation techniques including compression molding and injection molding, and physical properties of heat cure acrylic resins. It also compares heat cure resins to self-cure resins and discusses requirements versus clinical performance as well as recent advances in the material.
Physical properties of dental materials /certified fixed orthodontic courses...Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
Concrete permeability is a key factor in its durability. Permeability is affected by water-cement ratio, with lower ratios producing less permeable concrete. Curing also impacts permeability. Proper curing, including moist curing, produces less permeable concrete. Permeability testing involves measuring water flow through a sample over time under pressure. Sulfate attack can occur when sulfates penetrate permeable concrete and form expansive compounds that crack the material. Resistance to sulfates is improved with lower permeability concrete.
This document discusses the mechanical properties of dental materials. It defines key terms like force, stress, strain, elastic deformation and plastic deformation. It describes different types of stresses like tensile, compressive, shear and flexural stresses. It also discusses strength properties and how they are measured. Factors like stress concentration and flaws can reduce the clinical strength of dental materials. Understanding mechanical properties is important for optimizing the performance of dental materials.
This study evaluated the mechanical properties of various dental cement and core materials over time. Compressive strength increased for all materials from 15 minutes to 1 hour to 24 hours after mixing. Ketac Silver showed the highest compressive strength at all time periods. Diametral tensile strength also increased over time for most materials. At 24 hours, Chelon Silver, Ketac Silver, and Miracle Mix showed the highest values. For flexural strength, Ketac Silver produced the highest values at 24 hours, increasing more than any other material from 1 hour. In conclusion, setting time influences mechanical properties, and Ketac Silver demonstrated the strongest performance overall.
This study evaluated the sag resistance of four base metal alloys commonly used in long-span metal ceramic frameworks. 80 metal specimens were fabricated and divided into 4 groups - groups I and II were "as cast" and with surface finishing, respectively. Each specimen underwent 3 simulated porcelain firing cycles and sag-related deflection was measured. It was found that the "as cast" samples (group I) had significantly less sag than finished samples. Among the alloys, Co-Cr alloys exhibited the least amount of sag, with values of 14.8μm for Wirobond SG and 19.4μm for the Ni-Cr alloy Wiron 99. The results show that surface modifications increase sag and Co-Cr
A hardness testing machine was designed, fabricated, and tested. Four materials - mild steel, brass, aluminum, and copper - were tested under varying loads. Mild steel was found to be the hardest material based on indentation diameter measurements. The fabricated machine produced satisfactory results and could help address the scarcity of hardness testing machines in educational institutions.
System shear connector jakarta digunakan sebagai aplikasi dalam konstruksi bangunan untuk menghasilkan kekuatan coran beton lebih kuat dan stabil sesuai dengan perhitungan engineering civil. Dalam hal ini ada 2 hal perhitungan kekuatan secara umum yaitu kekuatan kelengketan stud pada batang baja sesudah dilas. Dan yang kedua adalah kekuatan stud bolt yang digunakan.
Class on "Porcelain layering on zirconia coping"
Presentation by Prof. Dr. Marco Ferrari MD, DMD, PhD.
http://www.dentalevo.it/dentistry-materials/porcelain-layering-zirconia-coping/
This document summarizes a master's thesis that experimentally and numerically studied the pull-out behavior of steel fibers in concrete. Experiments were conducted on straight and hooked steel fibers under various lateral pressures. The experiments showed large variations in results partly due to local crushing of the cement matrix. A numerical model was developed using an interface damage model and contact simulation to model fiber-concrete bonding. The model studies the influence of heterogeneous concrete properties on hooked fiber pull-out behavior by varying cement, aggregate, and interface strengths and toughnesses. Simulated results agreed with experiments, showing local concrete fracture influences pull-out behavior.
The document experimentally investigates the flexural behavior of cold-formed steel sections with triangular web corrugations. Three beam specimens with varying web depths of 200mm, 250mm, and 300mm were tested under two-point loading. The results show that flexural capacity increases with web depth. All beams failed by crushing of the top flange and lateral torsional buckling. Finite element analysis using ANSYS software correlated well with experimental results. The triangular web corrugations improved flexural strength compared to flat webs and prevented failure in the web or shear zones.
1 ijcmes dec-2015-17-optimization of friction stir welding parameters for joi...INFOGAIN PUBLICATION
Friction stir welding was a promising welding technology from the same moment of its existence because of its easy use, being ecologically friendly processed and with no need for filler metal. The present paper discusses the investigate the mechanical properties in order to demonstrate the feasibility of friction stir welding for joining Al 6061 aluminum alloy welding was performed on pipe. The pipe sections, 30mm, and relatively thin walled 2, 3 and 4 mm. Wire welded as similar alloy joints using (FSW) process In order to investigate the effect of rotation speed 485,710, 910, 1120,1400 and 1800 RPM and travel speeds 4, 8 and 10 mm/min. On mechanical propertie.
This work also focuses on mathematic models such as regression analysis (RA) to predict the tensile strength, the percentage of elongation and hardness of friction stir welded 6061 aluminum alloy. The Tensile strength, the percentage of elongation and hardness of weld joints were predicted by taking the parameters Tool rotation speed, material thickness and travel speed as a function. The results obtained through regresion analysis The models have been proved to be successful in terms of agreement with experimental results ratio 94.6%.
Experimental investigation of concrete beams reinforced with gfrp barsIAEME Publication
This document summarizes an experimental study that tested seven concrete beams reinforced with locally produced glass fiber reinforced polymer (GFRP) bars. The study investigated the effect of reinforcement ratio (1.7 times balanced reinforcement ratio (μb) and 2.7 times μb) and concrete compressive strength (25 MPa and 45 MPa) on the beams' deflection, cracking, ultimate load capacity, and GFRP reinforcement strains. The test results showed that higher reinforcement ratios led to smaller crack widths and deflections, and higher ultimate loads. Specimens with 2.7 times μb reinforcement demonstrated ductile behavior from the concrete. The recorded GFRP strains reached 90% of the bars' ultimate strains.
Forming Limit Prediction of High Tensile Strength Steel using FEA SimulationIJERD Editor
Forming limit prediction of High Tensile Strength Steel (HTSS) sheet was carried out by using finite element analysis. JSTAMP/NV was used in the finite element analysis. Thickness of HTSS specimen was 1.0mm, and the length was 120mm.And the width was varied from 20mm to 80mm. Stretching test was operated by Erichsen test. In this study, the forming limit prediction method for predicting the localized necking before the fracture was proposed.FLD of HTSS was compared between experimental results and analytical results. Forming limit diagrams (FLD) obtained by FEAagreed well with the FLD obtained by experiment.
silver nanoparticles relation on properties of silicone elastomerdellasain
The document summarizes two journal articles on the effect of adding nanoparticles like silver and titanium dioxide to maxillofacial silicone elastomers.
The first article studied the effect of adding silver nanoparticles at 20 ppm on the tear strength, hardness, and color stability of Teksil 25 silicone. It found silver nanoparticles decreased hardness but did not significantly change tear strength or color stability.
The second article examined how different concentrations of titanium dioxide nanoparticles (2%, 4%, 6%) affected the mechanical and anti-aging properties of MDX4-4210 silicone. It concluded 6% TiO2 improved tensile strength, tear strength, hardness and provided better anti-aging protection against thermal, UV and stress fatigue compared to
This document summarizes a research study that evaluated the effect of thermal cycling on the shear bond strength of porcelain/Ti–6Al–4V interfaces prepared by furnace firing and hot pressing. Thermal cycling was performed between 571°C and 60.7°C in an artificial saliva for 5000 cycles to simulate intraoral temperatures. After thermal cycling, shear bond tests were performed. The results showed that most polished-fired specimens fractured during thermal cycling, so their bond strength could not be measured. The sandblasted-fired, polished-hot pressed, and sandblasted-hot pressed specimens had bond strengths of 76.27±15.9 MPa, 52.27±23.6 MPa
A fracture mechanics based method for prediction ofSAJITH GEORGE
The document presents a fracture mechanics-based method for predicting cracking in circular and elliptical concrete rings undergoing restrained shrinkage. It describes an experimental program using different ring geometries and material tests to determine properties. A numerical model is developed using ANSYS to model the restrained shrinkage process and calculate stress intensity factors. The model uses a fictitious temperature field to simulate shrinkage and determines cracking age by comparing driving and resistance curves. It finds cracking occurs earlier in elliptical rings and the method accurately predicts experimental cracking ages.
The Comparison of Properties of Tinplates during Uniaxial and Biaxial Stresstheijes
The majority of thin steel sheets is used to make of food covers, cans, capsules and other products, which are produced by metal forming. Concerning considerable changes in production of tinplates and still higher requests on their properties there is requirement to use such methods on their evaluation, which are able to determine especially mechanical and plastic properties of sheets quickly and with the low costs. Following of present know-how there were developed new testing methods, which correspond more to steel sheets stress during technological treatment (concerning their stress-strain state). In the contribution we deal with the comparison of properties of tinplates during uniaxial tensile test and biaxial tensile test.
Flexural Fatigue of Steel SAE 1040 and GFRP Automotive Anti Roll BarsPadmanabhan Krishnan
This document summarizes numerical and experimental investigations on the flexural fatigue behavior of glass/epoxy composite and SAE 1040 steel tubes for automotive applications. Static and fatigue flexural tests were conducted on composite and steel tube specimens. The composite specimens exhibited matrix cracking and delamination under static loading and additional damage like fiber pull-out under higher fatigue loads. Steel specimens showed plain morphology under lower fatigue loads but cracks and severe damage under higher loads. Finite element analysis using ANSYS was also conducted to predict fatigue life. Scanning electron microscopy revealed failure mechanisms like cracking and striations. Composite tubes showed potential to withstand high cycle fatigue loading.
The document summarizes research testing the effect of steel fiber volume fraction on the flexural strength of high-strength concrete beams. 25 beams were tested with steel fiber volumes from 0.5-4%. Testing showed flexural strength increased with higher fiber volumes. As fiber content increased, the failure mode transitioned from shear to flexure. Load-deflection curves showed higher maximum loads and deflections for beams with more fibers. In conclusion, adding steel fibers increases flexural strength of beams, especially at lower fiber volumes.
The purpose of the experimental work presented in this study is to study the effect
of concrete compressive strength and steel reinforcement ratio on capacity and
deflection of reinforced concrete two-way slabs. Three steel reinforcement ratios are
considered which are minimum, maximum and average of them in addition to two
concrete compressive strength
values of 20 and 30 MPa. The results from
experimental work show that increasing the reinforcing steel ratio leads to increase the
ultimate capacity of the slab in addition to decrease the maximum deflection. For slabs
with
= 20 MPa, increasing the reinforcing steel ratio from the minimum to the
maximum, i.e. 600 %, leads to increase ultimate capacity by about 156 % and decrease
maximum deflection by about 52 %. Wheras, For slabs with
= 30 MPa, increasing
the reinforcing steel ratio from the minimum to the maximum, i.e. 900 %, leads to
increase ultimate capacity by about 155 % and decrease maximum central deflection
by about 27 %. In addition, matmatical expresions for load-deflection relationships are
presented in the current study
SUGGESTING DEFLECTION EXPRESSIONS FOR RC 2-WAY SLABSIAEME Publication
The purpose of the experimental work presented in this study is to study the effect
of concrete compressive strength and steel reinforcement ratio on capacity and
deflection of reinforced concrete two-way slabs. Three steel reinforcement ratios are
considered which are minimum, maximum and average of them in addition to two
concrete compressive strength
values of 20 and 30 MPa. The results from
experimental work show that increasing the reinforcing steel ratio leads to increase the
ultimate capacity of the slab in addition to decrease the maximum deflection. For slabs
with
= 20 MPa, increasing the reinforcing steel ratio from the minimum to the
maximum, i.e. 600 %, leads to increase ultimate capacity by about 156 % and decrease
maximum deflection by about 52 %. Wheras, For slabs with
= 30 MPa, increasing
the reinforcing steel ratio from the minimum to the maximum, i.e. 900 %, leads to
increase ultimate capacity by about 155 % and decrease maximum central deflection
by about 27 %. In addition, matmatical expresions for load-deflection relationships are
presented in the current study.
Comparison of Fatigue Characteristic for AISI 1039 Steel with Surface Treatmentijceronline
Wear and fatigue resistance in steel components used in various industries can be improved by surface treatments. Coatings systems which are used for improving the mechanical properties, generally, decreased the components fatigue life due to micro cracks, that propagate through the substrate , it is possible to improve the fatigue resistance of a component by the application of shot peening treatment, whose compressive residual stresses delay or eliminate the initiation and propagation of fatigue cracks. The aim of this study is to obtain the fatigue limit of untreated, shot peened, and hard chromium coating of medium carbon steel AISI 1039 and comparison between them. Fatigue tests were carried out using small samples with 4 mm diameter, with hard chromium layer of (47.1) µm thick. Rotating-bending fatigue test was carried out on samples after shot peening with steel balls of about 20 minutes peening time. Experimental results showed that hard chromium electroplating decreased the fatigue life and fatigue limit in comparison with the uncoated steel. As the highest thickness for coating was 23µm. On the other hand, Shot peening Results indicated that the fatigue strengths of samples are increased and the highest fatigue limit was (298.566Mpa) after treated the samples by shot peening for 20 minutes.
Similar to Flexural strengthofveneeringceramicsforzirconia (20)
The document discusses fundamentals of software testing including definitions of testing, why testing is necessary, seven testing principles, and the test process. It describes the test process as consisting of test planning, monitoring and control, analysis, design, implementation, execution, and completion. It also outlines the typical work products created during each phase of the test process.
Test Management as Chapter 5 of ISTQB Foundation. Topics covered are Test Organization, Test Planning and Estimation, Test Monitoring and Control, Test Execution Schedule, Test Strategy, Risk Management, Defect Management
EverHost AI Review: Empowering Websites with Limitless Possibilities through ...SOFTTECHHUB
The success of an online business hinges on the performance and reliability of its website. As more and more entrepreneurs and small businesses venture into the virtual realm, the need for a robust and cost-effective hosting solution has become paramount. Enter EverHost AI, a revolutionary hosting platform that harnesses the power of "AMD EPYC™ CPUs" technology to provide a seamless and unparalleled web hosting experience.
Dev Dives: Mining your data with AI-powered Continuous DiscoveryUiPathCommunity
Want to learn how AI and Continuous Discovery can uncover impactful automation opportunities? Watch this webinar to find out more about UiPath Discovery products!
Watch this session and:
👉 See the power of UiPath Discovery products, including Process Mining, Task Mining, Communications Mining, and Automation Hub
👉 Watch the demo of how to leverage system data, desktop data, or unstructured communications data to gain deeper understanding of existing processes
👉 Learn how you can benefit from each of the discovery products as an Automation Developer
🗣 Speakers:
Jyoti Raghav, Principal Technical Enablement Engineer @UiPath
Anja le Clercq, Principal Technical Enablement Engineer @UiPath
⏩ Register for our upcoming Dev Dives July session: Boosting Tester Productivity with Coded Automation and Autopilot™
👉 Link: https://bit.ly/Dev_Dives_July
This session was streamed live on June 27, 2024.
Check out all our upcoming Dev Dives 2024 sessions at:
🚩 https://bit.ly/Dev_Dives_2024
QR Secure: A Hybrid Approach Using Machine Learning and Security Validation F...AlexanderRichford
QR Secure: A Hybrid Approach Using Machine Learning and Security Validation Functions to Prevent Interaction with Malicious QR Codes.
Aim of the Study: The goal of this research was to develop a robust hybrid approach for identifying malicious and insecure URLs derived from QR codes, ensuring safe interactions.
This is achieved through:
Machine Learning Model: Predicts the likelihood of a URL being malicious.
Security Validation Functions: Ensures the derived URL has a valid certificate and proper URL format.
This innovative blend of technology aims to enhance cybersecurity measures and protect users from potential threats hidden within QR codes 🖥 🔒
This study was my first introduction to using ML which has shown me the immense potential of ML in creating more secure digital environments!
Elasticity vs. State? Exploring Kafka Streams Cassandra State StoreScyllaDB
kafka-streams-cassandra-state-store' is a drop-in Kafka Streams State Store implementation that persists data to Apache Cassandra.
By moving the state to an external datastore the stateful streams app (from a deployment point of view) effectively becomes stateless. This greatly improves elasticity and allows for fluent CI/CD (rolling upgrades, security patching, pod eviction, ...).
It also can also help to reduce failure recovery and rebalancing downtimes, with demos showing sporty 100ms rebalancing downtimes for your stateful Kafka Streams application, no matter the size of the application’s state.
As a bonus accessing Cassandra State Stores via 'Interactive Queries' (e.g. exposing via REST API) is simple and efficient since there's no need for an RPC layer proxying and fanning out requests to all instances of your streams application.
For senior executives, successfully managing a major cyber attack relies on your ability to minimise operational downtime, revenue loss and reputational damage.
Indeed, the approach you take to recovery is the ultimate test for your Resilience, Business Continuity, Cyber Security and IT teams.
Our Cyber Recovery Wargame prepares your organisation to deliver an exceptional crisis response.
Event date: 19th June 2024, Tate Modern
Leveraging AI for Software Developer Productivity.pptxpetabridge
Supercharge your software development productivity with our latest webinar! Discover the powerful capabilities of AI tools like GitHub Copilot and ChatGPT 4.X. We'll show you how these tools can automate tedious tasks, generate complete syntax, and enhance code documentation and debugging.
In this talk, you'll learn how to:
- Efficiently create GitHub Actions scripts
- Convert shell scripts
- Develop Roslyn Analyzers
- Visualize code with Mermaid diagrams
And these are just a few examples from a vast universe of possibilities!
Packed with practical examples and demos, this presentation offers invaluable insights into optimizing your development process. Don't miss the opportunity to improve your coding efficiency and productivity with AI-driven solutions.
MySQL InnoDB Storage Engine: Deep Dive - MydbopsMydbops
This presentation, titled "MySQL - InnoDB" and delivered by Mayank Prasad at the Mydbops Open Source Database Meetup 16 on June 8th, 2024, covers dynamic configuration of REDO logs and instant ADD/DROP columns in InnoDB.
This presentation dives deep into the world of InnoDB, exploring two ground-breaking features introduced in MySQL 8.0:
• Dynamic Configuration of REDO Logs: Enhance your database's performance and flexibility with on-the-fly adjustments to REDO log capacity. Unleash the power of the snake metaphor to visualize how InnoDB manages REDO log files.
• Instant ADD/DROP Columns: Say goodbye to costly table rebuilds! This presentation unveils how InnoDB now enables seamless addition and removal of columns without compromising data integrity or incurring downtime.
Key Learnings:
• Grasp the concept of REDO logs and their significance in InnoDB's transaction management.
• Discover the advantages of dynamic REDO log configuration and how to leverage it for optimal performance.
• Understand the inner workings of instant ADD/DROP columns and their impact on database operations.
• Gain valuable insights into the row versioning mechanism that empowers instant column modifications.
DynamoDB to ScyllaDB: Technical Comparison and the Path to SuccessScyllaDB
What can you expect when migrating from DynamoDB to ScyllaDB? This session provides a jumpstart based on what we’ve learned from working with your peers across hundreds of use cases. Discover how ScyllaDB’s architecture, capabilities, and performance compares to DynamoDB’s. Then, hear about your DynamoDB to ScyllaDB migration options and practical strategies for success, including our top do’s and don’ts.
Corporate Open Source Anti-Patterns: A Decade LaterScyllaDB
A little over a decade ago, I gave a talk on corporate open source anti-patterns, vowing that I would return in ten years to give an update. Much has changed in the last decade: open source is pervasive in infrastructure software, with many companies (like our hosts!) having significant open source components from their inception. But just as open source has changed, the corporate anti-patterns around open source have changed too: where the challenges of the previous decade were all around how to open source existing products (and how to engage with existing communities), the challenges now seem to revolve around how to thrive as a business without betraying the community that made it one in the first place. Open source remains one of humanity's most important collective achievements and one that all companies should seek to engage with at some level; in this talk, we will describe the changes that open source has seen in the last decade, and provide updated guidance for corporations for ways not to do it!
Enterprise Knowledge’s Joe Hilger, COO, and Sara Nash, Principal Consultant, presented “Building a Semantic Layer of your Data Platform” at Data Summit Workshop on May 7th, 2024 in Boston, Massachusetts.
This presentation delved into the importance of the semantic layer and detailed four real-world applications. Hilger and Nash explored how a robust semantic layer architecture optimizes user journeys across diverse organizational needs, including data consistency and usability, search and discovery, reporting and insights, and data modernization. Practical use cases explore a variety of industries such as biotechnology, financial services, and global retail.
An Introduction to All Data Enterprise IntegrationSafe Software
Are you spending more time wrestling with your data than actually using it? You’re not alone. For many organizations, managing data from various sources can feel like an uphill battle. But what if you could turn that around and make your data work for you effortlessly? That’s where FME comes in.
We’ve designed FME to tackle these exact issues, transforming your data chaos into a streamlined, efficient process. Join us for an introduction to All Data Enterprise Integration and discover how FME can be your game-changer.
During this webinar, you’ll learn:
- Why Data Integration Matters: How FME can streamline your data process.
- The Role of Spatial Data: Why spatial data is crucial for your organization.
- Connecting & Viewing Data: See how FME connects to your data sources, with a flash demo to showcase.
- Transforming Your Data: Find out how FME can transform your data to fit your needs. We’ll bring this process to life with a demo leveraging both geometry and attribute validation.
- Automating Your Workflows: Learn how FME can save you time and money with automation.
Don’t miss this chance to learn how FME can bring your data integration strategy to life, making your workflows more efficient and saving you valuable time and resources. Join us and take the first step toward a more integrated, efficient, data-driven future!
Call Girls Kochi 💯Call Us 🔝 7426014248 🔝 Independent Kochi Escorts Service Av...
Flexural strengthofveneeringceramicsforzirconia
1. Flexural strength of veneering ceramics for zirconia
J. Fischer *, B. Stawarczyk, C.H.F. Ha¨mmerle
Clinic for Fixed and Removable Prosthodontics, Center for Dental and Oral Medicine, University of Zurich, Plattenstrasse 11,
CH-8032 Zurich, Switzerland
1. Introduction
Yttria-stabilized zirconia (Y-TZP) provides a sufficient
mechanical strength to be used in frameworks for all-ceramic
fixed partial dentures.1,2
For esthetical reasons, these frame-
works have to be veneered with an appropriate veneering
ceramic. In clinical application, the veneering ceramic
revealed to be the weakest link in such reconstructions.3–5
Chipping of the veneer is described to be the most frequent
reason for failure with a failure rate of 15.2% after a service
time of 35.1 Æ 13.8 months.5
Among other reasons failure of a veneer may be caused by
insufficient bond strength,6–8
excessive tensile stress due to a
thermal mismatch between veneer and framework9
or
excessive load due to premature contacts.10
The bond strength
was intensely investigated.9,11–13
It revealed to be in the range
of that measured with metal-ceramic systems. The tensile
stress in the veneering ceramic is established during cooling
after firing, when an unequal thermal contraction of both
layers happens. The coefficients of thermal expansion should
be adjusted in a way that during cooling a slight compression
of the veneering ceramic occurs to enhance its strength.14
In
j o u r n a l o f d e n t i s t r y 3 6 ( 2 0 0 8 ) 3 1 6 – 3 2 1
a r t i c l e i n f o
Article history:
Received 21 September 2007
Received in revised form
18 January 2008
Accepted 25 January 2008
Keywords:
Zirconia
Veneering ceramics
Three-point flexural strength
Four-point flexural strength
Biaxial flexural strength
a b s t r a c t
Objectives: The flexural strengths of veneering ceramics for zirconia were compared.
Methods: With 10 different veneering ceramics for zirconia (test group) and three different
veneering ceramics for the metal-ceramic technique (control group) three-point flexural
strength and biaxial flexural strength according to ISO 6872: 1995 as well as four-point
flexural strength according to EN 843-1: 2005 were measured (n = 10). Statistical analysis was
performed with one-way ANOVA and post hoc Scheffe´ test (SPSS, p < 0.05).
Results: For the test group, three-point flexural strength ranged between 77.8 Æ 8.7 and
106.6 Æ 12.5 MPa without any statistically significant differences, biaxial flexural strength
between 69.1 Æ 4.8 and 101.4 Æ 10.5 MPa with three homogeneous groups and four-point
flexural strength between 59.5 Æ 6.2 and 89.2 Æ 9.5 MPa with five homogeneous groups. The
control group showed three-point flexural strength values ranging from 93.3 Æ 13.5 to
149.4 Æ 20.5 MPa, biaxial flexural strength values from 93.4 Æ 10.0 to 141.2 Æ 11.6 MPa,
and four-point flexural strength values from 82.7 Æ 8.5 to 116.9 Æ 9.8 MPa. In every case,
the results of the four-point flexure test were significantly lower than those obtained in the
three-point flexure test. The three-point flexural strengths of the test group are similar to
those of two ceramics of the control group. The flexural strength of one ceramic of the
control group significantly exceeded the strengths of all other ceramics investigated.
Conclusion: Three-point flexural strength values of veneering ceramics for zirconia are
similar to those of veneering ceramics for the metal-ceramic technique. The four-point
flexure test among all three tests showed highest discrimination between the different
ceramic materials.
# 2008 Elsevier Ltd. All rights reserved.
* Corresponding author. Tel.: +41 44 634 33 67; fax: +41 44 634 43 05.
E-mail address: jens.fischer@zzmk.uzh.ch (J. Fischer).
available at www.sciencedirect.com
journal homepage: www.intl.elsevierhealth.com/journals/jden
0300-5712/$ – see front matter # 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.jdent.2008.01.017
2. metal-ceramic systems, excessive stress to some extent may
be compensated by thermal creep of the alloy, i.e. plastic flow,
especially if a high gold alloy is used.15,16
In all-ceramic
systems, the ceramic framework is rigid and does not yield to
the stress induced by a thermal mismatch to that extent.
Therefore, the risk of destructive stress formed in the veneer
layer might be higher in all-ceramic systems and thus would
require a high mechanical strength for veneering materials for
all-ceramic systems. Hence, the strength of the veneering
ceramic is a crucial parameter for the clinical long-term
success. For metal-ceramic restorations failure rates after 5
years, caused by chipping of the veneer are reported to be 0.4%
for single crowns17
and 2.9% for fixed partial dentures.18
Hence, veneering ceramics for zirconia should at least show a
flexural strength, which is similar to that of veneering
ceramics for alloys.
Flexural strength can be measured in a three-point flexure
test, a four-point flexure test or a biaxial flexure test. In all
cases, static load is applied until failure. In the three-point
flexure test, a non-uniform central stress field is created, while
in the four-point flexure test the stress field is uniform
between the two loading pistons. In the biaxial flexure test,
where a disk is loaded in the center, the probability of edge
failures is reduced.19
The results of the three-point flexure test
and the four-point flexure test are correlated.20
Lower values
were found for the four-point flexure test compared to both
other tests, but the relation between three-point flexure test
and biaxial flexure test was not uniform for all ceramics
investigated.
To the knowledge of the investigators, no systematic
investigation of the flexural strength of veneering ceramics for
zirconia is available.
Aim of the present study therefore was to measure the
flexural strength of a variety of commercially available
veneering ceramics for zirconia to provide a comprehensive
analysis of the mechanical strength of these products.
2. Materials and methods
Three-point flexural strength, four-point flexural strength and
biaxial flexural strength of 10 different veneering ceramics for
zirconia according to Table 1 were measured. As control three
ceramics for the metal-ceramic technique were additionally
included (Imagine Reflex, IPS d.sign, and VM13).
Specimenswere prepared according to ISO 6872: 1995 (three-
point and biaxial flexural strength) or DIN EN 843-1: 2005 (four-
point flexural strength). Separable steel molds were used to
layer the ceramic. Ceramic powder and an appropriate amount
of the respective liquid were mixed to form a sticky slurry,
which was filled into the mold. Excess liquid was sucked off
with a tissue. Only dentin was layered. Firing of the specimens
was performed in a ceramic oven (Austromat D4, Dekema,
Freilassing, Germany) according to therecommendations of the
manufacturers (Table 2). The specimens were placed on a tray,
which was covered with a layer of silica powder. After firing, the
specimens were ground to the final dimensions using SiC discs
P220, P500 and P1200 according to ISO 6344-1: 1998. As required
by the standards the two faces of the specimens did not differ
more than 0.05 mm in parallelism. Ten specimens were
prepared for each series. The dimensions of the samples were
measured to the next 0.01 mm. The specimens were placed in
the appropriate sample holder and loaded in a universal testing
machine (Z010, Zwick, Ulm, Germany) with a cross-head speed
of 1 mm/min until failure. The flexural strength was calculated
as mean of the 10 results.
Statistical analysis between different test methods and
between the ceramics were analyzed with one-way ANOVA,
Table 1 – Veneering ceramics used in the investigation
Veneering ceramics for the metal-ceramic technique are highlighted.
j o u r n a l o f d e n t i s t r y 3 6 ( 2 0 0 8 ) 3 1 6 – 3 2 1 317
3. followed by a post hoc Scheffe´ test (SPSS Inc., Chicago, IL, USA;
p < 0.05).
2.1. Three-point flexural strength
Specimens with a final size of 4 Æ 0.25 mm in width,
1.2 Æ 0.2 mm in thickness and a length of at least 20 mm
were produced.
The sample holder had a span between the two bearers of
15 mm. Supports and loading piston were steel knife edges,
rounded to a radius of 0.8 mm. Load was applied at the
midpoint of the specimens. The flexural strength was
calculated according to the equation
s ¼
3Fl
2bh2
where s is the maximum center tensile stress (MPa), F the load
at fracture (N), l the distance of the two supports (mm), b the
width of the specimen (mm) and h is the height of the speci-
men (mm).
2.2. Four-point flexural strength
Specimens with a final size of 2.5 Æ 0.25 mm in width,
2.0 Æ 0.2 mm in thickness and a length of at least 25 mm
were used.
The sample holder had a span between the two bearers of
20 mm. The distance between the two loading pistons was
10 mm. Supports and both loading pistons were steel knife
edges, rounded to a radius of 1.25 mm. The flexural strength
was calculated according to the equation
s ¼
3Fd
2bh2
where s is the maximum center tensile stress (MPa), F the load
at fracture (N), d the difference in the distance of the two
supports and the distance of the two loading pistons (mm), b
the width of the specimen (mm) and h is the height of the
specimen (mm).
2.3. Biaxial flexural strength
Disk-shaped specimens, 12 Æ 0.2 mm in diameter and
1.2 Æ 0.2 mm in height were prepared. The specimens were
tested in a biaxial flexure jig with a piston on three balls design
as described in the standard. The balls had a diameter of
3.2 mm and were arranged in an angle of 1208 to each other on
a circle of 10 mm in diameter. Loading at 1 mm/min was
applied in the center of the specimen with a 1.5 mm diameter
steel rod. Calculation of the biaxial flexural strength was
performed with the following equation:
s ¼
À0:2387FðX À YÞ
d2
where s is the maximum center tensile stress (MPa), F the load
at fracture (N), X = (1 + n) ln(r2/r3)2
+ [(1 À n)/2] (r2/r3)2
and
Y = (1 + n)[ln(r1/r3)2
] + (1 À n)(r2/r3)2
.
In which, n is the Poisson’s ratio, r1 the radius of the support
circle (mm), r2 the radius of the loaded area (mm), r3 the radius
of the specimen (mm) and d is the specimens thickness at the
fracture origin (mm).
Poisson’s ratio was taken as 0.25 for all ceramics according
to the recommendation in the standard.
3. Results
Means and respective standard deviations for three-point
flexural strength, four-point flexural strength and biaxial
flexural strength are shown in Table 3 and Fig. 1. For every
ceramic the values of the three-point flexural strength were
significantly higher than those of the four-point flexural
Table 2 – Firing schedules of the veneering ceramics
Vacuum was used until the final temperature was reached. Veneering ceramics for the metal-ceramic technique are highlighted.
j o u r n a l o f d e n t i s t r y 3 6 ( 2 0 0 8 ) 3 1 6 – 3 2 1318
4. strength. Statistical significant differences were found
between three-point flexural strength and biaxial flexural
strength for the following ceramics: Cerabien ZR, Initial ZR and
Vintage ZR, while significant differences between biaxial
flexural strength and four-point flexural strength occurred
with Cerabien ZR, Lava Ceram, Rondo Zirconia, Triceram,
Zirox and VM13. In Table 3, the homogeneous groups with no
statistically significant differences between the different
ceramics are marked. In the three-point flexure test, the
strength values of the veneering ceramics for zirconia showed
no statistically significant difference (group a). In the biaxial
flexure test, three different homogeneous groups (c–e) of
veneering ceramics for zirconia can be distinguished and in
the four-point flexure test there were found five different
groups (g, h, j, k, l) by statistical analysis. In the three-point
flexure test, the values of the veneering ceramics for zirconia
were similar to those of Reflex and IPS d.sign. In the biaxial
flexure test, the flexure strengths of Cerabien ZR and Vintage
ZR and in the four-point flexure test the flexure strengths of
Cerabien ZR, Vintage ZR, IPS e.max, Zirox, Lava Ceram and
Initial ZR were significantly lower than those of the veneering
ceramics for the metal-ceramic technique. The flexural
strength of VM13 in every case significantly exceeded those
of the other ceramics investigated.
Table 3 – Flexural strength values of the veneering ceramics (mean W S.D.), arranged in ascending order of the values for
the four-point flexural strength
Identical letters following the values indicate homogeneous groups. Veneering ceramics for the metal-ceramic technique are highlighted.
Fig. 1 – Flexural strength values and standard deviations of veneering ceramics.
j o u r n a l o f d e n t i s t r y 3 6 ( 2 0 0 8 ) 3 1 6 – 3 2 1 319
5. Linear regression analysis revealed the following coeffi-
cients of determination:
three-point/four-point: R2
= 0.89, s3-pt = 1.24s4-pt;
three-point/biaxial: R2
= 0.90, s3-pt = 1.07sbiax;
biaxial/four-point: R2
= 0.92, sbiax = 1.16s4-pt.
4. Discussion
The results of this study revealed that the three-point flexural
strength values of veneering ceramics for zirconia are in the
same range as those of veneering ceramics for metal-ceramic
systems. The regression analysis showed that the results of all
three test methods are correlated. However, the three-point
flexure test yielded the highest values. Compared to the four-
point flexure test this difference was significant for all
materials, compared to the biaxial flexure test only for three
out of 13 ceramics. The biaxial flexure test in turn showed
significantly higher values compared to the four-point test
results for six out of 13 ceramics. But in general, it can be
concluded that all three test designs provided the same
relative order of the results. The four-point flexure test
provided highest discrimination between the different cera-
mic materials, resulting in statistically significant differences
between some veneering ceramics for zirconia and the
control.
Similar biaxial flexural strength results as obtained in the
present investigation are reported for leucite reinforced
ceramics.21–23
IPS d.sign showed a biaxial flexural strength
of 98.19 Æ 5.71 MPa,23
which is comparable to the value
measured in the present investigation (95.5 Æ 7.8 MPa). A
further investigation employed biaxial flexure test and four-
point flexure test.24
Comparably low values for a body and an
opaque ceramic for the metal-ceramic technique were found,
but the relation between the results of both test methods was
the same as in the present study. In another investigation, it is
reported that IPS d.sign had a flexural strength in the three-
point, four-point and biaxial flexure strength test of
124.3 Æ 12.4, 77.9 Æ 7.9 and 114.3 Æ 13.3 MPa, respectively.20
These values are quite high compared to the present
investigation. Nevertheless, the authors also found a correla-
tion between the three test methods, which was in the same
order as in the present study. In a further study, it is reported
that the three-point flexure strength of alumina was higher
than that obtained in a biaxial flexure strength while this value
was higher than the results obtained in a four-point flexure
test, which again is in accordance with the present findings.25
The difference in the results of the three different test
designs may be explained as follows. Flexural strength
obtained with the four-point flexure test is generally lower
because the probability to have a surface crack between the
two loading pistons is higher than in the more limited area
beneath the loading piston of a three-point flexure test. In
the biaxial flexure test, the force is applied in the center of
the specimen. Defects at the edges, which most probably
lead to an early failure, are less effective. Nevertheless, the
probability of a crack in the vicinity of the loading piston is
higher than in the three-point flexure test because the
loaded area is larger.19
Consistent with Ban and Anusavice,24
it can be concluded that for screening tests, for instance,
during the development of ceramics, the biaxial flexure test
is most appropriate because preparation of the samples is
easy, compared to the three- and four-point flexure tests.
But, according to the present results, when a scientific
approach is intended, the four-point flexure test should be
preferred.
The fact that the strength of veneering ceramics for
zirconia is in the same order as that of veneering materials
for metal-ceramics could be interpreted in the sense that the
strength of the veneering ceramics are not the limiting factor
for the clinical long-term success of zirconia restorations.
Nevertheless, compared to metal-ceramics excessive chipping
is observed in clinical studies with zirconia restorations.3–5
To
explain this effect, two aspects have to be considered. One
aspect is the stress, built during cooling after firing of the
veneering ceramic. In metal-ceramic systems, this stress may
be at least partially relaxed by an elastic or plastic deformation
of the substructure.15
Especially, high-gold alloys show a low
sag-resistance.16
A zirconia substructure in contrast is rigid,
which leads to higher stress formation. Hence, compared to
metal-ceramics a higher flexural strength of the veneering
ceramic is favorable to provide a high reliability of the veneer.
The present investigation has shown that, depending on the
test method and the brand, the flexural strength of veneering
ceramics for zirconia is rather similar or even lower than that
of veneering ceramics for the metal-ceramic technique.
Therefore, the effort to improve the veneering ceramics for
zirconia should be directed to the optimal adjustment of the
thermal expansion and the increase of mechanical strength,
which is in accordance with the appraisal of other authors.26
A
second point is the fact that in the oral cavity water exposure
may cause hydrolysis of the Si–O–Si bonds, thus affecting the
mechanical properties of the ceramic. Flexural strength values
are obtained at ambient laboratory conditions. The increased
failure rate of veneering ceramics for zirconia under humid
conditions in the oral cavity may be attributed to a different
chemical composition compared to ceramics for the metal-
ceramic technique, resulting in a higher susceptibility for
hydrolytic attack. Further investigations are scheduled to test
this hypothesis.
5. Conclusion
Within the limitations of this in vitro study, the following
conclusions can be drawn:
(1) Four-point flexural strength values of all materials tested
were significantly lower than those obtained with the
three-point flexure test. The biaxial flexural strength in
general ranged between the four-point flexural strength
and the three-point flexural strength.
(2) Strength values of veneering ceramics for zirconia are
similar to those of veneering ceramics for the metal-
ceramic technique.
Acknowledgement
The materials were kindly provided by the respective
manufacturers.
j o u r n a l o f d e n t i s t r y 3 6 ( 2 0 0 8 ) 3 1 6 – 3 2 1320
6. r e f e r e n c e s
1. Sturzenegger B, Fehe´r A, Lu¨ thy H, Scha¨rer P, Gauckler LJ.
Reliability and strength of all-ceramic dental restorations
fabricated by direct ceramic machining (DCM). International
Journal of Computerized Dentistry 2001;4:89–106.
2. Lu¨ thy H, Filser F, Loeffel O, Schuhmacher M, Gauckler LJ,
Ha¨mmerle CHF. Strength and reliability of four unit all-
ceramic posterior bridge. Dental Materials 2005;21:930–7.
3. Vult von Steyern P, Carlson P, Nilner K. All-ceramic fixed
partial dentures designed according to the DC-Zirkon
technique. A 2-year clinical study. Journal of Oral
Rehabilitation 2005;32:180–7.
4. Sailer I, Fehe´r A, Filser F, Lu¨ thy H, Gauckler LJ, Scha¨rer P,
et al. Prospective clinical study of zirconia posterior fixed
partial dentures: 3-year follow-up. Quintessence International
2006;37:685–93.
5. Sailer I, Fehe´r A, Filser F, Gauckler LJ, Lu¨ thy H, Ha¨mmerle
CHF. Five-year clinical results of zirconia frameworks for
posterior fixed partial dentures. International Journal of
Prosthodontics 2007;20:383–8.
6. al-Shehri SA, Mohammed H, Wilson CA. Influence of
lamination on the flexure strength of dental castable
ceramic. Journal of Prosthetic Dentistry 1996;76:23–8.
7. Isgro G, Pallav P, van der Zel JM, Feilzer AJ. The influence of
the veneering porcelain and different surface treatments on
the biaxial flexure strength of a heat-pressed ceramic.
Journal of Prosthetic Dentistry 2003;90:465–73.
8. De Jager N, Pallav P, Feilzer AJ. The influence of design
parameters on the FEA-determined stress distribution in
CAD-CAM produced all-ceramic crowns. Dental Materials
2005;21:242–51.
9. Aboushelib MN, de Jager N, Kleverlaan CJ, Feilzer AJ.
Microtensile bond strength of different components of core
veneered all-ceramic restorations. Dental Materials
2005;21:984–91.
10. Drummond JL, King TJ, Bapna MS, Koperski RD. Mechanical
property evaluation of pressable restorative ceramics. Dental
Materials 2000;16:226–33.
11. Luthardt RG, Sandkuhl O, Reitz B. Zirconia-TZP and
alumina—advanced technologies for the manufacturing of
single crowns. The European Journal of Prosthodontics and
Restorative Dentistry 1999;7:113–9.
12. Aboushelib MN, de Jager N, Kleverlaan CJ, Feilzer AJ.
Microtensile bond strength of different components of core
veneered all-ceramic restorations. Part II: Zirconia
veneering ceramics. Dental Materials 2006;22:857–63.
13. Al-Dohan HM, Yaman P, Dennison JB, Razzoog ME,
Lang BR. Shear strength of core-veneer interface in
bi-layered ceramics. Journal of Prosthetic Dentistry
2004;91:349–55.
14. Bagby M, Marshall SJ, Marshall GW. Metal ceramic
compatibility: a review of the literature. Journal of Prosthetic
Dentistry 1990;63:21–5.
15. Anusavice KJ, Carroll JE. Effect of incompatibility stress on
the fit of metal-ceramic crowns. Journal of Dental Research
1987;66:1341–5.
16. Fischer J, Fleetwood PW, Baltzer N. Thermal creep analysis
of precious metal alloys for the ceramic-fused-to-metal
technique. Journal of Biomedical Material Research (Applied
Biomaterials) 1999;48:258–64.
17. Pjetursson BE, Sailer I, Zwahlen M, Ha¨mmerle CHF. A
systematic review of the survival and complication rates of
all-ceramic and metal-ceramic reconstructions after an
observation period of at least 3 years. Part I: single crowns.
Clinical Oral Implant Research 2007;18:73–85.
18. Pjetursson BE, Sailer I, Zwahlen M, Ha¨mmerle CHF. A
systematic review of the survival and complication rates of
all-ceramic and metal-ceramic reconstructions after an
observation period of at least 3 years. Part II: fixed
partial dentures. Clinical Oral Implant Research 2007;
18:86–96.
19. Anusavice KJ, Kakar K, Ferree N. Which mechanical and
physical testing methods are relevant for predicting the
clinical performance of ceramic-based dental prostheses?
Clinical Oral Implants Research 2007;18:218–31.
20. Jin J, Takahashi H, Iwasaki N. Effect of test method on
flexural strength of recent dental ceramics. Dental Materials
Journal 2004;23:490–6.
21. Shareef MY, Van Noort R, Messer PF, Piddock V. The effect of
microstructural features on the biaxial flexural strength of
leucite reinforced glass ceramics. Journal of Materials Science
Materials in Medicine 1994;5:113–8.
22. Cattell MJ, Clarke RL, Lynch EJR. The biaxial flexural strength
and reliability of four dental ceramics—part II. Journal of
Dentistry 1997;25:409–14.
23. Sinmazisik C, O¨ vecoglu ML. Physical properties and
microstructural characterization of dental porcelains mixed
with distilled water and modeling liquid. Dental Materials
2006;22:735–45.
24. Ban S, Anusavice KJ. Influence of test method on failure
stress of brittle dental materials. Journal of Dental Research
1990;69:1791–9.
25. Shetty DK, Rosenfield AR, Duckworth WH, Held PR. A
biaxial-flexure test for evaluating ceramic strengths. Journal
of the American Ceramic Society 1983;66:36–42.
26. Aboushelib MN, de Jager N, Kleverlaan CJ, Feilzer AJ. Effect
of loading method on the fracture mechanics of two layered
all-ceramic restorative systems. Dental Materials
2007;23:952–9.
j o u r n a l o f d e n t i s t r y 3 6 ( 2 0 0 8 ) 3 1 6 – 3 2 1 321
7. Abstract:
Objectives: The flexural strengths of veneering ceramics for zirconia were compared.Methods: With 10 different
veneering ceramics for zirconia (test group) and three different veneering ceramics for the metal-ceramic technique
(control group) three-point flexural strength and biaxial flexural strength according to ISO 6872: 1995 as well as
four-point flexural strength according to EN 843-1: 2005 were measured (n = 10). Statistical analysis was
performed with one-way ANOVA and post hoc Scheffe´ test (SPSS, p < 0.05).
Results: For the test group, three-point flexural strength ranged between 77.8 +/- 8.7 and 106.6 +/- 12.5 MPa without
any statistically significant differences, biaxial flexural strength between 69.1 +/- 4.8 and 101.4 +/- 10.5 MPa with three
homogeneous groups and four-point
flexural strength between 59.5 +/- 6.2 and 89.2 +/- 9.5 MPa with five homogeneous groups. The control group showed
three-point flexural strength values ranging from 93.3 +/- 13.5 to 149.4 +/- 20.5 MPa, biaxial flexural strength values
from 93.4 +/- 10.0 to 141.2 +/- 11.6 MPa,
and four-point flexural strength values from 82.7 +/- 8.5 to 116.9 +/- 9.8 MPa. In every case, the results of the four-point
flexure test were significantly lower than those obtained in the three-point flexure test. The three-point flexural strengths
of the test group are similar to those of two ceramics of the control group. The flexural strength of one ceramic of the
control group significantly exceeded the strengths of all other ceramics investigated.
Conclusion: Three-point flexural strength values of veneering ceramics for zirconia are
similar to those of veneering ceramics for the metal-ceramic technique. The four-point
flexure test among all three tests showed highest discrimination between the different
ceramic materials.