The document discusses materials testing and various types of tests, including destructive and non-destructive tests. Destructive tests include tensile tests, compression tests, torsion tests, impact tests, hardness tests, fatigue tests, and creep tests. Non-destructive tests include scanning electron microscopy, radiography, atomic force microscopy, liquid penetration testing, and ultrasonic testing. The document focuses on tensile tests and provides details on how they are conducted, what properties they measure (e.g. yield strength, ultimate tensile strength, modulus of elasticity), and how to interpret stress-strain curves. Examples of calculations using data from tensile tests are also provided.
This document discusses various mechanical properties that are important for selecting materials for structural components. It describes different types of mechanical tests like tension, compression, torsion, bending, impact and fatigue tests that are conducted on metal specimens to determine properties like strength, ductility and toughness. Specifically, it outlines the process for a uniaxial tension test including the equipment used, steps to conduct the test, and how to analyze the stress-strain diagram produced. It also discusses factors that influence mechanical properties like temperature, notches, grain size and hardness tests.
The document discusses various mechanical properties of materials important for manufacturing including modulus, yield strength, tensile strength, stress-strain relationships, ductility, toughness, hardness, and fatigue. It explains how properties like modulus, strength, and stress-strain behavior are evaluated using tensile tests, and how properties like ductility, toughness, and hardness are measured and related to a material's suitability for manufacturing processes. Comparative data on the mechanical properties of common materials like metals, ceramics, polymers is also presented.
Mechanical properties of materials (lecture+2).pdfHeshamBakr3
The document discusses the mechanical properties of materials when subjected to different types of loading like axial, lateral, and torsional loads. It defines concepts like stress, strain, elastic and plastic deformation. It explains stress-strain diagrams and how they are used to determine properties like modulus of elasticity, yield strength, tensile strength, ductility, toughness, and resilience. Typical stress-strain behaviors of ductile and brittle materials are compared. Examples of determining properties from stress-strain curves are also provided.
This document discusses mechanical properties that can be determined from tensile and shear tests. It defines key terms like stress, strain, elastic modulus, yield strength, and tensile strength. A typical stress-strain curve is shown and each region is explained. The elastic portion is linear up to the yield point, then the plastic region involves necking and strain hardening until ultimate failure. True stress and strain account for changes in cross-sectional area during deformation. The document also compares properties like ductility and toughness between different materials.
This experiment tested the tensile properties of steel, aluminum, and two polymeric materials. Specimens of each material were pulled apart in a tensile testing machine at a constant strain rate to measure properties like yield strength, tensile strength, and elongation. The engineering stress-strain and true stress-strain curves were plotted and compared for each material. Values for properties like Young's modulus, yield stress, and tensile strength were determined from the curves and compared to literature values. Sources of experimental error were also discussed.
This document discusses mechanical properties and how they relate to material behavior under stress. It defines key terms like elastic modulus, yield strength, tensile strength, and ductility. It then describes how these properties are measured in a tensile test, including defining the stress-strain curve and regions like elastic, yield, plastic and necking. True stress and strain are introduced to provide a more accurate representation of material behavior. Strain hardening is described as the phenomenon where plastic deformation causes materials to strengthen.
Tensile testing is used to determine the strength and ductility of materials. A specimen is placed in grips and pulled apart under increasing tensile force while measuring elongation. The resulting stress-strain curve provides properties like yield strength, tensile strength, and Young's modulus. Tensile tests are important for engineering design and quality control by ensuring materials can withstand expected loads and comparing new materials. Common applications include testing aircraft components, bolts, and other loaded structures.
Hammad Shoaib submitted a lab report for the Mechanics of Solids course to determine various mechanical properties of materials through tensile and bend tests. The report describes procedures to develop a stress-strain curve for steel rebar and determine its yield strength, ultimate strength, modulus of elasticity, and percentage elongation. Additional experiments include a bend test to examine ductility and a tensile test on wood to find compressive strengths parallel and perpendicular to the grain.
This document discusses various mechanical properties that are important for selecting materials for structural components. It describes different types of mechanical tests like tension, compression, torsion, bending, impact and fatigue tests that are conducted on metal specimens to determine properties like strength, ductility and toughness. Specifically, it outlines the process for a uniaxial tension test including the equipment used, steps to conduct the test, and how to analyze the stress-strain diagram produced. It also discusses factors that influence mechanical properties like temperature, notches, grain size and hardness tests.
The document discusses various mechanical properties of materials important for manufacturing including modulus, yield strength, tensile strength, stress-strain relationships, ductility, toughness, hardness, and fatigue. It explains how properties like modulus, strength, and stress-strain behavior are evaluated using tensile tests, and how properties like ductility, toughness, and hardness are measured and related to a material's suitability for manufacturing processes. Comparative data on the mechanical properties of common materials like metals, ceramics, polymers is also presented.
Mechanical properties of materials (lecture+2).pdfHeshamBakr3
The document discusses the mechanical properties of materials when subjected to different types of loading like axial, lateral, and torsional loads. It defines concepts like stress, strain, elastic and plastic deformation. It explains stress-strain diagrams and how they are used to determine properties like modulus of elasticity, yield strength, tensile strength, ductility, toughness, and resilience. Typical stress-strain behaviors of ductile and brittle materials are compared. Examples of determining properties from stress-strain curves are also provided.
This document discusses mechanical properties that can be determined from tensile and shear tests. It defines key terms like stress, strain, elastic modulus, yield strength, and tensile strength. A typical stress-strain curve is shown and each region is explained. The elastic portion is linear up to the yield point, then the plastic region involves necking and strain hardening until ultimate failure. True stress and strain account for changes in cross-sectional area during deformation. The document also compares properties like ductility and toughness between different materials.
This experiment tested the tensile properties of steel, aluminum, and two polymeric materials. Specimens of each material were pulled apart in a tensile testing machine at a constant strain rate to measure properties like yield strength, tensile strength, and elongation. The engineering stress-strain and true stress-strain curves were plotted and compared for each material. Values for properties like Young's modulus, yield stress, and tensile strength were determined from the curves and compared to literature values. Sources of experimental error were also discussed.
This document discusses mechanical properties and how they relate to material behavior under stress. It defines key terms like elastic modulus, yield strength, tensile strength, and ductility. It then describes how these properties are measured in a tensile test, including defining the stress-strain curve and regions like elastic, yield, plastic and necking. True stress and strain are introduced to provide a more accurate representation of material behavior. Strain hardening is described as the phenomenon where plastic deformation causes materials to strengthen.
Tensile testing is used to determine the strength and ductility of materials. A specimen is placed in grips and pulled apart under increasing tensile force while measuring elongation. The resulting stress-strain curve provides properties like yield strength, tensile strength, and Young's modulus. Tensile tests are important for engineering design and quality control by ensuring materials can withstand expected loads and comparing new materials. Common applications include testing aircraft components, bolts, and other loaded structures.
Hammad Shoaib submitted a lab report for the Mechanics of Solids course to determine various mechanical properties of materials through tensile and bend tests. The report describes procedures to develop a stress-strain curve for steel rebar and determine its yield strength, ultimate strength, modulus of elasticity, and percentage elongation. Additional experiments include a bend test to examine ductility and a tensile test on wood to find compressive strengths parallel and perpendicular to the grain.
This document summarizes key concepts from a chapter on strain in mechanics of materials. It discusses two main types of strain - normal and shear - and how stress and strain define a material's mechanical properties. It then focuses on axial deformation and stress-strain diagrams, describing how tensile tests are conducted to generate these diagrams for materials like steel. Key points on the stress-strain curve are identified, such as proportional limit, yield point, ultimate stress, and how they relate to a material's elastic region and factors of safety in design.
This document discusses various concepts related to stress and strain. It begins by explaining the three main types of loads - tension, compression, and shear. It then provides diagrams demonstrating these different types of loads. The document goes on to define engineering stress and strain and discuss their units. Several mechanical properties are also defined, including yield strength, ultimate tensile strength, and elongation. Finally, the document discusses various tests used to determine mechanical properties, including tensile, compression, hardness, and impact tests.
This document provides an introduction to strength of materials (SOM). It defines key terms like strength, stiffness, stability, and durability. It discusses the basic problem in SOM as developing methods to design structural elements that consider strength, stiffness, stability, and economy. It also outlines the main hypotheses in SOM, including the material being continuous, homogeneous, and isotropic. It then discusses different types of stresses like tensile, compressive, and shear stresses. It provides stress-strain curves for ductile materials and defines modulus of elasticity. Examples of calculating stresses and strains in structural elements are also provided.
Structural Integrity Analysis: Chapter 3 Mechanical Properties of MaterialsIgor Kokcharov
Structural Integrity Analysis features a collection of selected topics on structural design, safety, reliability, redundancy, strength, material science, mechanical properties of materials, composite materials, welds, finite element analysis, stress concentration, failure mechanisms and criteria. The engineering approaches focus on understanding and concept visualization rather than theoretical reasoning. The structural engineering profession plays a key role in the assurance of safety of technical systems such as metallic structures, buildings, machines, and transport. The third chapter explains the engineering tests and fundamentals of mechanical properties of materials.
This document discusses mechanical properties of materials as determined through tensile testing. It describes three main regions in a stress-strain curve: the elastic region where deformation is recoverable, the plastic region where permanent deformation occurs, and the failure point where the material fractures. Key properties like elastic modulus, yield strength, tensile strength, and ductility can be determined from the stress-strain curve generated through tensile testing, where a material sample is stretched until failure. The properties influence a material's behavior under mechanical loads and are important considerations for engineering design and manufacturing.
The static tension test determines the strength of a material when subjected to stretching. A standard test specimen is pulled slowly until failure using a testing machine. The shape is usually round, square, or rectangular. Dimensions depend on standards but the gage length must have a uniform cross-section. The stress-strain diagram is analyzed to determine properties like yield stress, tensile strength, elongation, modulus of elasticity, and toughness. True stress and true strain consider changes in cross-sectional area during plastic deformation.
Experiment 4 - Testing of Materials in Tension Object .docxSANSKAR20
Experiment 4 - Testing of Materials in Tension
Object: The object of this experiment is to measure the tensile properties of two polymeric
materials, steel and aluminum at a constant strain rate on the Tension testing machine.
Background: For structural applications of materials such as bridges, pressure vessels, ships,
and automobiles, the tensile properties of the metal material set the criteria for a safe design.
Polymeric materials are being used more and more in structural applications, particularly in
automobiles and pressure vessels. New applications emerge as designers become aware of
the differences in the properties of metals and polymers and take full advantage of them. The
analyses of structures using metals or plastics require that the data be available.
Stress-Strain: The tensile properties of a material are obtained by pulling a specimen of
known geometry apart at a fixed rate of straining until it breaks or stretches to the machines
limit. It is useful to define the load per unit area (stress) as a parameter rather than load to
avoid the confusion that would arise from the fact that the load and the change in length are
dependent on the cross-sectional area and original length of the specimen. The stress,
however, changes during the test for two reasons: the load increases and the cross-sectional
area decreases as the specimen gets longer.
Therefore, the stress can be calculated by two formulae which are distinguished as
engineering stress and true stress, respectively.
(1) = P/Ao= Engineering Stress (lbs/in
2 or psi)
P = load (lbs)
Ao= original cross-sectional area (in
2)
(2) T= P/Ai = True Stress
Ai = instantaneous cross-sectional area (in
2)
Likewise, the elongation is normalized per unit length of specimen and is called strain. The
strain may be based on the original length or the instantaneous length such that
(3) =(lf - lo)/ lo = l / lo = Engineering Strain, where
lf= final gage length (in)
lo= original gage length (in)
(4) T= ln ( li / lo ) = ln (1 +) = True Strain, where
li = instantaneous gage length (in)
ln = natural logarithm
For a small elongation the engineering strain is very close to the true strain when l=1.2 lo,
then = 0.2 and T= ln 1.2 = 0.182. The engineering stress is related to the true stress by
(5) T= (1 + )
The true stress would be 20% higher in the case above where the specimen is 20% longer
than the original length. As the relative elongation increases, the true strain will become
significantly less than the engineering strain while the true stress becomes much greater than
the engineering stress. When l= 4.0 lo then = 3.0 but the true strain =ln 4.0 = 1.39.
Therefore, the true strain is less than 1/2 of the engineering strain. The true stress (T) = (1+
3.0) = 4, or the true stress is 4 times the engineering stress.
Tensile Test Nom ...
This document discusses the mechanical properties of solids. It covers topics such as elasticity, stress and strain, mechanical testing techniques for properties like hardness, ductility, deformation mechanisms, fracture, and fatigue. Elasticity is divided into elastic deformation, where the material returns to its original shape, and plastic deformation, where the shape is permanently changed. Stress is defined as force over cross-sectional area while strain is the change in length over original length. Various mechanical tests are used to characterize properties like hardness, toughness, and ductility. Deformation, fracture, and fatigue failure mechanisms are also examined.
This document is a report on stress, strain, and their measurement. It discusses stress and strain concepts such as normal stress, shear stress, tensile strain, and compressive strain. It also examines stress-strain curves and how they are used to determine material properties. Measurement devices for stress and strain are described, including strain gauges. The report concludes that stress and strain are important concepts in mechanics of materials and their measurement allows determination of material behaviors.
The document discusses various mechanical properties of metals including stiffness, strength, ductility, toughness, hardness, stress and strain. It defines key terms like elastic modulus, yield strength, ultimate strength, elongation, area reduction, fracture strain. It explains concepts such as engineering stress-strain curves, Hooke's law, elastic deformation, plastic deformation, Poisson's ratio, ductile vs brittle materials, and how properties relate to microstructure. Typical testing methods and how to calculate properties from raw data are also summarized.
The document discusses stress-strain curves, which plot the stress and strain of a material sample under load. It describes the typical stress-strain behavior of ductile materials like steel and brittle materials like concrete. For ductile materials, the curve shows an elastic region, yield point, strain hardening region, and ultimate strength before failure. The yield point marks the transition between elastic and plastic deformation. The document also discusses factors that influence a material's yield stress, such as temperature and strain rate, and implications for structural engineering like reduced buckling strength after yielding.
This document provides an overview of general properties of materials relevant to manufacturing processes. It discusses various material types and their mechanical, physical and chemical properties. Key mechanical properties discussed include strength, toughness, hardness, ductility, elasticity, fatigue, creep, failure under tension, compression, torsion, impact and bending. Testing methods for properties like tensile strength, hardness and impact strength are also covered. The document aims to help understand how material selection and properties influence manufacturing process selection and design.
This document discusses various topics related to mechanical design including types of loads and stresses, theories of failure, stress concentration, fatigue, creep, and design of cotter joints. It defines stress and strain, describes different types of loading and the resulting stresses. It discusses various theories of failure for predicting failure under different stress conditions. It also covers stress concentration, factors affecting it, and methods to reduce it. Fatigue behavior is described using S-N curves and endurance limits. Creep behavior and different creep stages are outlined. Design of cotter joints is explained focusing on its components and advantages.
The document discusses stress and strain in engineering materials. It defines stress as the resistance force generated per unit area, and strain as the ratio of change in length under force to the original length. It describes different types of stress including tensile, compressive, and shear stress. It also defines important aspects of a stress-strain curve including elastic limit, yield points, ultimate tensile stress, and breaking stress. Hooke's law and Poisson's ratio are explained. Stress-strain curves for different materials are shown to illustrate how materials respond differently to stresses.
Machine elements are basic mechanical components that are combined to form machines. They experience various stresses from forces like loads, temperature changes, and vibrations. Stresses produce strains in the elements. The relationship between stress and strain is linear within the elastic limit according to Hooke's law. Different types of stresses like tensile, compressive, shear, and bearing are discussed along with the corresponding strains. Material properties important for design like modulus of elasticity, Poisson's ratio, and stress-strain diagrams are also introduced. Factors to consider for selecting appropriate materials and factors of safety for machine elements are outlined.
This section provides a very useful introduction to the concepts of direct and shear stress and strain as encountered in mechanical engineering structures. The standard notation used is explained in some detail. Young’s modulus is introduced and explained with worked examples of standard types of simple calculations. Factors of safety are examined and their importance is explored with once again some sample calculations included. Some simple examples of basic shear stress are also given.
Em321 lesson 08b solutions ch6 - mechanical properties of metalsusna12345
This document discusses mechanical properties that can be determined from a stress-strain curve obtained via tensile testing. It defines stress and strain, explains elastic and plastic deformation, and introduces key properties like modulus of elasticity, yield strength, ultimate tensile strength, ductility, toughness, and resilience. An example stress-strain curve is analyzed to find these properties numerically. The document emphasizes that stress-strain curves are commonly used instead of force-displacement plots to characterize materials.
The document discusses various mechanical properties of materials including stress-strain relationships, hardness, and the effect of temperature on properties. It describes common tests used to evaluate these properties such as tensile, compression, bending, and hardness tests. The tensile test is used to generate a stress-strain curve and determine properties like elastic modulus, yield strength, ultimate tensile strength, and ductility. The shape of the stress-strain curve provides information about the material's behavior and properties.
Demonstration of Mechanical Behaviour of Material Using a Practical Approach Dr.Gaurav Kumar Gugliani
This document announces an online workshop on demonstrating the mechanical behavior of materials using practical approaches. The workshop will be held on May 10, 2020 from 11:00 AM to 12:30 PM and will be conducted by Dr. Gaurav Gugliani and Mr. Pawan Bhawsar from the Department of Mechanical Engineering at Mandsaur University. The workshop will provide an introduction to mechanical engineering and mechanical properties, discuss stress-strain and its types, material properties, and elastic moduli. It will also demonstrate stress-strain diagrams and the universal testing machine along with the types of tests performed on it.
Demonstration of Mechanical Behaviour of Material Using a Practical Approach Dr. Gaurav Kumar Gugliani
This document announces an online workshop on demonstrating the mechanical behavior of materials using practical approaches. The workshop will be held on May 10, 2020 from 11:00 AM to 12:30 PM and presented by Dr. Gaurav Gugliani and Mr. Pawan Bhawsar. The presentation will introduce mechanical engineering, mechanical properties, stress-strain types, material properties, elastic moduli, and stress-strain diagrams. It will also demonstrate the use of a universal testing machine and the types of tests it can perform.
This document summarizes key concepts from a chapter on strain in mechanics of materials. It discusses two main types of strain - normal and shear - and how stress and strain define a material's mechanical properties. It then focuses on axial deformation and stress-strain diagrams, describing how tensile tests are conducted to generate these diagrams for materials like steel. Key points on the stress-strain curve are identified, such as proportional limit, yield point, ultimate stress, and how they relate to a material's elastic region and factors of safety in design.
This document discusses various concepts related to stress and strain. It begins by explaining the three main types of loads - tension, compression, and shear. It then provides diagrams demonstrating these different types of loads. The document goes on to define engineering stress and strain and discuss their units. Several mechanical properties are also defined, including yield strength, ultimate tensile strength, and elongation. Finally, the document discusses various tests used to determine mechanical properties, including tensile, compression, hardness, and impact tests.
This document provides an introduction to strength of materials (SOM). It defines key terms like strength, stiffness, stability, and durability. It discusses the basic problem in SOM as developing methods to design structural elements that consider strength, stiffness, stability, and economy. It also outlines the main hypotheses in SOM, including the material being continuous, homogeneous, and isotropic. It then discusses different types of stresses like tensile, compressive, and shear stresses. It provides stress-strain curves for ductile materials and defines modulus of elasticity. Examples of calculating stresses and strains in structural elements are also provided.
Structural Integrity Analysis: Chapter 3 Mechanical Properties of MaterialsIgor Kokcharov
Structural Integrity Analysis features a collection of selected topics on structural design, safety, reliability, redundancy, strength, material science, mechanical properties of materials, composite materials, welds, finite element analysis, stress concentration, failure mechanisms and criteria. The engineering approaches focus on understanding and concept visualization rather than theoretical reasoning. The structural engineering profession plays a key role in the assurance of safety of technical systems such as metallic structures, buildings, machines, and transport. The third chapter explains the engineering tests and fundamentals of mechanical properties of materials.
This document discusses mechanical properties of materials as determined through tensile testing. It describes three main regions in a stress-strain curve: the elastic region where deformation is recoverable, the plastic region where permanent deformation occurs, and the failure point where the material fractures. Key properties like elastic modulus, yield strength, tensile strength, and ductility can be determined from the stress-strain curve generated through tensile testing, where a material sample is stretched until failure. The properties influence a material's behavior under mechanical loads and are important considerations for engineering design and manufacturing.
The static tension test determines the strength of a material when subjected to stretching. A standard test specimen is pulled slowly until failure using a testing machine. The shape is usually round, square, or rectangular. Dimensions depend on standards but the gage length must have a uniform cross-section. The stress-strain diagram is analyzed to determine properties like yield stress, tensile strength, elongation, modulus of elasticity, and toughness. True stress and true strain consider changes in cross-sectional area during plastic deformation.
Experiment 4 - Testing of Materials in Tension Object .docxSANSKAR20
Experiment 4 - Testing of Materials in Tension
Object: The object of this experiment is to measure the tensile properties of two polymeric
materials, steel and aluminum at a constant strain rate on the Tension testing machine.
Background: For structural applications of materials such as bridges, pressure vessels, ships,
and automobiles, the tensile properties of the metal material set the criteria for a safe design.
Polymeric materials are being used more and more in structural applications, particularly in
automobiles and pressure vessels. New applications emerge as designers become aware of
the differences in the properties of metals and polymers and take full advantage of them. The
analyses of structures using metals or plastics require that the data be available.
Stress-Strain: The tensile properties of a material are obtained by pulling a specimen of
known geometry apart at a fixed rate of straining until it breaks or stretches to the machines
limit. It is useful to define the load per unit area (stress) as a parameter rather than load to
avoid the confusion that would arise from the fact that the load and the change in length are
dependent on the cross-sectional area and original length of the specimen. The stress,
however, changes during the test for two reasons: the load increases and the cross-sectional
area decreases as the specimen gets longer.
Therefore, the stress can be calculated by two formulae which are distinguished as
engineering stress and true stress, respectively.
(1) = P/Ao= Engineering Stress (lbs/in
2 or psi)
P = load (lbs)
Ao= original cross-sectional area (in
2)
(2) T= P/Ai = True Stress
Ai = instantaneous cross-sectional area (in
2)
Likewise, the elongation is normalized per unit length of specimen and is called strain. The
strain may be based on the original length or the instantaneous length such that
(3) =(lf - lo)/ lo = l / lo = Engineering Strain, where
lf= final gage length (in)
lo= original gage length (in)
(4) T= ln ( li / lo ) = ln (1 +) = True Strain, where
li = instantaneous gage length (in)
ln = natural logarithm
For a small elongation the engineering strain is very close to the true strain when l=1.2 lo,
then = 0.2 and T= ln 1.2 = 0.182. The engineering stress is related to the true stress by
(5) T= (1 + )
The true stress would be 20% higher in the case above where the specimen is 20% longer
than the original length. As the relative elongation increases, the true strain will become
significantly less than the engineering strain while the true stress becomes much greater than
the engineering stress. When l= 4.0 lo then = 3.0 but the true strain =ln 4.0 = 1.39.
Therefore, the true strain is less than 1/2 of the engineering strain. The true stress (T) = (1+
3.0) = 4, or the true stress is 4 times the engineering stress.
Tensile Test Nom ...
This document discusses the mechanical properties of solids. It covers topics such as elasticity, stress and strain, mechanical testing techniques for properties like hardness, ductility, deformation mechanisms, fracture, and fatigue. Elasticity is divided into elastic deformation, where the material returns to its original shape, and plastic deformation, where the shape is permanently changed. Stress is defined as force over cross-sectional area while strain is the change in length over original length. Various mechanical tests are used to characterize properties like hardness, toughness, and ductility. Deformation, fracture, and fatigue failure mechanisms are also examined.
This document is a report on stress, strain, and their measurement. It discusses stress and strain concepts such as normal stress, shear stress, tensile strain, and compressive strain. It also examines stress-strain curves and how they are used to determine material properties. Measurement devices for stress and strain are described, including strain gauges. The report concludes that stress and strain are important concepts in mechanics of materials and their measurement allows determination of material behaviors.
The document discusses various mechanical properties of metals including stiffness, strength, ductility, toughness, hardness, stress and strain. It defines key terms like elastic modulus, yield strength, ultimate strength, elongation, area reduction, fracture strain. It explains concepts such as engineering stress-strain curves, Hooke's law, elastic deformation, plastic deformation, Poisson's ratio, ductile vs brittle materials, and how properties relate to microstructure. Typical testing methods and how to calculate properties from raw data are also summarized.
The document discusses stress-strain curves, which plot the stress and strain of a material sample under load. It describes the typical stress-strain behavior of ductile materials like steel and brittle materials like concrete. For ductile materials, the curve shows an elastic region, yield point, strain hardening region, and ultimate strength before failure. The yield point marks the transition between elastic and plastic deformation. The document also discusses factors that influence a material's yield stress, such as temperature and strain rate, and implications for structural engineering like reduced buckling strength after yielding.
This document provides an overview of general properties of materials relevant to manufacturing processes. It discusses various material types and their mechanical, physical and chemical properties. Key mechanical properties discussed include strength, toughness, hardness, ductility, elasticity, fatigue, creep, failure under tension, compression, torsion, impact and bending. Testing methods for properties like tensile strength, hardness and impact strength are also covered. The document aims to help understand how material selection and properties influence manufacturing process selection and design.
This document discusses various topics related to mechanical design including types of loads and stresses, theories of failure, stress concentration, fatigue, creep, and design of cotter joints. It defines stress and strain, describes different types of loading and the resulting stresses. It discusses various theories of failure for predicting failure under different stress conditions. It also covers stress concentration, factors affecting it, and methods to reduce it. Fatigue behavior is described using S-N curves and endurance limits. Creep behavior and different creep stages are outlined. Design of cotter joints is explained focusing on its components and advantages.
The document discusses stress and strain in engineering materials. It defines stress as the resistance force generated per unit area, and strain as the ratio of change in length under force to the original length. It describes different types of stress including tensile, compressive, and shear stress. It also defines important aspects of a stress-strain curve including elastic limit, yield points, ultimate tensile stress, and breaking stress. Hooke's law and Poisson's ratio are explained. Stress-strain curves for different materials are shown to illustrate how materials respond differently to stresses.
Machine elements are basic mechanical components that are combined to form machines. They experience various stresses from forces like loads, temperature changes, and vibrations. Stresses produce strains in the elements. The relationship between stress and strain is linear within the elastic limit according to Hooke's law. Different types of stresses like tensile, compressive, shear, and bearing are discussed along with the corresponding strains. Material properties important for design like modulus of elasticity, Poisson's ratio, and stress-strain diagrams are also introduced. Factors to consider for selecting appropriate materials and factors of safety for machine elements are outlined.
This section provides a very useful introduction to the concepts of direct and shear stress and strain as encountered in mechanical engineering structures. The standard notation used is explained in some detail. Young’s modulus is introduced and explained with worked examples of standard types of simple calculations. Factors of safety are examined and their importance is explored with once again some sample calculations included. Some simple examples of basic shear stress are also given.
Em321 lesson 08b solutions ch6 - mechanical properties of metalsusna12345
This document discusses mechanical properties that can be determined from a stress-strain curve obtained via tensile testing. It defines stress and strain, explains elastic and plastic deformation, and introduces key properties like modulus of elasticity, yield strength, ultimate tensile strength, ductility, toughness, and resilience. An example stress-strain curve is analyzed to find these properties numerically. The document emphasizes that stress-strain curves are commonly used instead of force-displacement plots to characterize materials.
The document discusses various mechanical properties of materials including stress-strain relationships, hardness, and the effect of temperature on properties. It describes common tests used to evaluate these properties such as tensile, compression, bending, and hardness tests. The tensile test is used to generate a stress-strain curve and determine properties like elastic modulus, yield strength, ultimate tensile strength, and ductility. The shape of the stress-strain curve provides information about the material's behavior and properties.
Demonstration of Mechanical Behaviour of Material Using a Practical Approach Dr.Gaurav Kumar Gugliani
This document announces an online workshop on demonstrating the mechanical behavior of materials using practical approaches. The workshop will be held on May 10, 2020 from 11:00 AM to 12:30 PM and will be conducted by Dr. Gaurav Gugliani and Mr. Pawan Bhawsar from the Department of Mechanical Engineering at Mandsaur University. The workshop will provide an introduction to mechanical engineering and mechanical properties, discuss stress-strain and its types, material properties, and elastic moduli. It will also demonstrate stress-strain diagrams and the universal testing machine along with the types of tests performed on it.
Demonstration of Mechanical Behaviour of Material Using a Practical Approach Dr. Gaurav Kumar Gugliani
This document announces an online workshop on demonstrating the mechanical behavior of materials using practical approaches. The workshop will be held on May 10, 2020 from 11:00 AM to 12:30 PM and presented by Dr. Gaurav Gugliani and Mr. Pawan Bhawsar. The presentation will introduce mechanical engineering, mechanical properties, stress-strain types, material properties, elastic moduli, and stress-strain diagrams. It will also demonstrate the use of a universal testing machine and the types of tests it can perform.
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
1. Introduction
Materials testing is a diligent approach to ensuring that your infrastructure and vital equipment will provide continued
production, undergo minimal degradation and are designed with optimal performance in mind. Materials testing can
also supply a wealth of information about the materials you are developing or incorporating into products to ensure
they perform within expected specifications.
Ensuring that crucial materials are fit for purpose presents a challenge to developers, operators and manufacturers
across many industries globally. You need assurance that your equipment and infrastructure will perform to the end of
its design life with minimal maintenance, failure mitigation and with mechanical strength prioritized and planned for.
It is an important for Materials engineers to understand how the various properties of materials are measured and what
those represents, the may be called upon to design structure/components using predetermined materials such that
unacceptable level of fracture and failure will not occur.
Many materials when in service, it subjected to a load such as tensile, compressive and shear. Factors to be considered
are nature of the applied load, its duration and the environment conditions.
2. There are two types of tests which are destructive and non-destructive tests.
Destructive tests include:
1. Tensile test
2. Compression test
3. Torsion test
4. Impact test
5. Hardness test
6. Fatigue test
7. Creep test
Non- destructive tests are:
1. Scanning electron microscope (SEM)
2. Radiographic test
3. Atomic Force Microscope
4. Liquid penetrate testing
5. Ultrasonic test
3. Destructive tests:
1. Tensile tests
Tensile stress (or tension) is the stress state leading to
expansion; that is, the length of a material tends to increase in
the tensile direction. The volume of the material stays constant.
When equal and opposite forces are applied on a body, then
the stress due to this force is called tensile stress. = F / Ao
>>>>>>>>>> equation 1
Stress unit is MPa = N/mm2
Figure (1) Specimen under tension force
4. Engineering strain is expressed as the ratio of total deformation to the initial dimension of the material
body in which the forces are being applied
Strain is unit less
Engineering strain ( ) = L - L / L >>>>>>equation 2
Figure (2) Elongation of specimen under tension force
5. The tension test is used to determine several mechanical properties of materials which are very important
in materials design. The specimen is mounted by its end into the holding grips of the testing instrument
(fig 1). The tensile instrument is designed to elongate the specimen at a constant rate around (2.5 to 3
mm/second), and spontaneously measure the load using transducer and the elongations using
extensometer. A stress-strain curve will be initiated takes several minutes and the specimen is
permanently deformed and usually fractured.
Figure (3) Instrument of Tensile Test
6. Specimen geometries specified by American Society for Testing and Materials (ASTM):
- Round specimens are preferred for extruded bars and castings (Fig2-a)
- Flat specimens are preferred when end-products are thin plates or sheets (Fig2-b)
Figure (4) Standard specimen of tensile test
7. Stress-strain curve
The stress-strain curve relates the applied stress to the resulting
strain and each material has its own unique stress-strain curve.
The initial straight line (0P)of the curve
characterizes proportional relationship between
the stress and the deformation (strain). the
relationship between the stress and the strain of
the specimen exhibits is linear.
The stress value at the point P is called the limit
of proportionality:
σp= FP / A0
Fig ( 5 ) Stress-strain diagram for mild steel
8. This behavior conforms to the Hook’s Law:
σ = E*
Where E is a constant, known as Young’s Modulus or Modulus of Elasticity.
The value of Young’s Modulus is determined mainly by the nature of the material and is nearly
insensitive to the heat treatment and composition.
Modulus of elasticity determines stiffness K - resistance of a body to elastic deformation caused by an
applied force. K = F / change of length (L - L )
The line 0E in the Stress-Strain curve indicates the range of elastic deformation – removal of
the load at any point of this part of the curve results in return of the specimen length to its
original value.
The elastic behavior is characterized by the elasticity limit (stress value at the point E):
σel= FE / A0
9. For the most materials the points P and E coincide and therefore σel=σp.
A point where the stress causes sudden deformation without any increase in the force is
called yield limit (yield stress, yield strength):
σy= FY / A0
The highest stress (point YU) , occurring before the sudden deformation is called upper
yield limit .
The lower stress value, causing the sudden deformation (point YL) is called lower yield
limit.
The commonly used parameter of yield limit is actually lower yield limit.
If the load reaches the yield point the specimen undergoes plastic deformation – it does not
return to its original length after removal of the load.
10. Ultimate tensile strength (UTS) is the maximum stress that can be sustained by the specimen undergoes tension force- the
point S in the diagram.
Tensile strengths may vary anywhere from 50 MPa for an aluminum to as high as 3000 MPa for the high-strength steels.
Ordinarily, when the strength of a metal is cited for design purposes, the yield strength is used. This is because by the time a
stress corresponding to the tensile strength has been applied, often a structure has experienced so much plastic deformation
that it is useless. Furthermore, fracture strengths are not normally specified for engineering design purposes.
- Continuation of the deformation results in breaking the specimen - the point B in the diagram.
Fig (6) Specimen behavior during tensile test
11. Offset yield point (proof stress)
When a yield point is not easily defined based on the shape of the stress-strain curve an offset yield point is arbitrarily defined.
High strength steel and non-ferrous alloys do not exhibit a yield point, so this offset yield point is used on these materials.
Further, this offset strain of 0.2% for yield stress is by ASTM, whereas in England, 0.1% and 0.5 % is commonly used.
Essentially 0.2% offset method of yield stress gives reproducible values though it is an approximate measure (and accepted in
engineering sense) of the transition from elastic to onset of plastic deformation.
Figure (7) offset yield method
12. Ductility
Ductility defines as the ability of materials to deform easily under tensile force or as the ability of materials to withstand the
plastic deformation without fracture. The materials that exhibit little or no ductility termed as brittle materials. Stress-strain
behavior for both ductile and brittle materials is shown in fig (8)
Ductility may be expressed quantitatively as either
percent elongation or percent
reduction in area. The percent elongation %EL is the
percentage of plastic strain
at fracture
% EL = (Lf - Lo / Lo) x 100 , where the Lo is the original
gauge length
% RA= (Ao-Af / A0 ) x 100 , where Af is the fracture area
Figure (8) Stress-strain behavior of Ductile and Brittle Materials
13. Resilience and Toughness
Resilience is the capacity of a material to absorb energy when it is deformed elastically and then, upon unloading, to have
this energy recovered. The modulus of resilience Ur is defined as the maximum energy that can be absorbed per unit
volume without creating a permanent distortion (joule/m3)
Ur = y
2 / 2E, where y is yield strength
Toughness it is a measure of the ability of a material to absorb energy up to fracture. The units for toughness are the
same as for resilience (i.e., energy per unit volume of material (joule/m3) )
. For a material to be tough, it must display both strength and ductility; often, ductile materials are tougher than brittle
ones
9
14. True stress and True strain
From fig 4 , the decline in the stress necessary to continue deformation past the maximum, point M, seems to indicate that the
metal is becoming weaker. However, the cross-sectional area is decreasing rapidly within the neck region, where deformation is
occurring. The stress, as computed from Equation 1, is on the basis of the original cross sectional area before any deformation,
and does not take into account this reduction in area at the neck. Sometimes it is more meaningful to use a true stress–true strain
scheme. True stress is defined as the load F divided by the instantaneous cross-sectional area over which deformation is
occurring (i.e., the neck, past the tensile point)
Engineering strain =
𝐿𝑖−𝐿𝑜
𝐿𝑜
where Li is actual length, Lo is gauge length
True strain = ln
𝐿𝑖
𝐿𝑜
E =
𝐿𝑖−𝐿𝑜
𝐿𝑜
=
Li
Lo
– 1, so
Li
Lo
= E + 1
T= ln (E +1)
15. Engineering stress E = F / Ao where Ao is original area
True stress (T) = F/ Ai , where Ai is the area where the fracture occurring at the necking region
Since the volume is constant Ao L0 = Ai Li >>>>> Ai = [
Li
Lo
] / Ao
T = F/ Ai =
F
Ao
[
Li
Lo
]
T = E (E +1)
For some metals and alloys, the region of the true stress/ strain curve up to M’ is approximated by:
T = K T
n
Where K and n are constants depend on whether the material has been cold worked, heat treated, etc
17. Ductile and Brittle materials fracture
Fracture: separation of a body into pieces due to stress, at temperatures below the melting point. Steps in fracture:
1- crack formation 2- crack propagation
In ductile fracture, the crack grows at a slow pace and is accompanied with a great deal of plastic deformation due to the
motion of dislocation. In this, the crack does not expand except when high levels of stress are present.
Under the view of a microscope, the surfaces of materials with ductile fracture appear irregular and rough, and exhibit some
dimpling
Figure (11) Steps of fracture for ductile materials
Figure (12) Dislocations motion in ductile
materials
18. Very little or no plastic deformation, Crack propagation is very fast , Crack propagates nearly perpendicular to the direction of
the applied stress, Crack often propagates by cleavage - breaking of atomic bonds along specific crystallographic planes
(cleavage planes).
Brittle Fracture
Figure (13) Crack propagation in Brittle materials
Figure (12) difference in cracks for ductile and
brittle materials
19. Examples:
1. For a bronze alloy, the stress at which plastic deformation begins is 280 MPa, and the modulus of elasticity is 115 GPa.
(a) What is the maximum load that may be applied to a specimen with a cross-sectional area of 325 mm2 without
plastic deformation?
(b) If the original specimen length is 120 mm, what is the maximum length to which it may be stretched without
causing plastic deformation?
Solution:
(a)This portion of the problem calls for a determination of the maximum load that can be applied without
plastic deformation (Fy). Taking the yield strength to be 280 MPa
Fy = σy Ao = (280 N/mm2 )(325 mm2 ) = 91000 N
𝑏 ∆𝑙 = Lo
= σ/E = 280x106 / 115x109 = 0.00243
Ly-120mm = 0.00243 x 120mm
Ly = 120.292 mm
20. Example #2:
From the tensile stress–strain behavior for the brass specimen shown in
Figure below determine the following:
(a) The modulus of elasticity
(b) The yield strength at a strain offset of 0.002
(c) The maximum load that can be sustained by a cylindrical specimen having
an original diameter of 12.8 mm
(d) The change in length of a specimen originally 250 mm long that
is subjected to a tensile stress of 345 MPa
21. a. E = slope = = Δ
Δ
=
2− 1
2−1
Its easier if we take 1 and 1 as zero.
For 2 = 150 MPa and 2 = 0.0016 , so
E=
150−0 MPa
0.0016−0
= 93.8 GPa
22. (b) The 0.002 strain offset line is constructed as shown in the inset; its intersection with the stress–strain curve is at
approximately 250 MPa which is the yield strength of the brass.
( c ) From the fig, the maximum tensile strength is 450 MPa
Fmax = max(ult) Ao = max(ult) x ( r2)
Fmax = ( 450 N/mm2 ) x ( (6.4 mm)2)
F max = 57900 N
(d) first necessary to determine the strain that is produced by a stress of 345 MPa. This is
accomplished by locating the stress point on the stress–strain curve, point A, and reading the
corresponding strain from the strain axis, which is approximately 0.06. Inasmuch as Lo= 250
mm, we have
∆l = Lo = 0.06 x 250 mm = 15mm.
23. Example 3:
A cylindrical specimen of steel having an original diameter of 12.8 mm is tensile tested to fracture and found to
have an engineering fracture strength of 460 MPa. If its cross-sectional diameter at fracture is 10.7 mm,
determine:
(a) The ductility in terms of percent reduction in area
(b) The true stress at fracture
(a) % RA= (Ao-Af / A0 ) x 100
%RA=
{
12.8
2
2−
10.7
2
2}
(10.7/2)2
x 100 = 30%
(b) True stress is defined the area is taken as the fracture area Af However, the load at fracture must
first be computed from the fracture strength as
F = f Ai = 460 MPa x [ (12.8/2 mm)2] = 59200 N
f represents engineering stress E which is determined using the initial area
T = F / Af
T = 59200/ (10.7/2)2
T = 660 MPa
24. Example 4: A cylindrical specimen of aluminum having a diameter of 12.8 mm and a gauge length of 50.800 mm
is pulled in tension. Use the load–elongation characteristics shown in the following table to complete parts (a)
through (e).
Load Length
N mm
0 50.800
7,330 50.851
15,100 50.902
23,100 50.952
30,400 51.003
34,400 51.054
38,400 51.308
41,300 51.816
44,800 52.832
46,200 53.848
47,300 54.864
47,500 55.880
46,100 56.896
44,800 57.658
42,600 58.420
36,400 59.1
(a) Plot the data as engineering stress versus
engineering strain.
(b) Compute the modulus of elasticity.
(c) Determine the yield strength at a strain offset
of 0.002.
(d) Determine the tensile strength of this alloy.
(e) What is the approximate ductility, in percent
elongation?
25. (a)The data are plotted below on two plots: the first corresponds to the entire stress–strain curve, while
for the second, the curve extends to just beyond the elastic region of deformation.
= F/A
When the load is 7330 N , so = F/ r2
= 7330 / (12.8/2)2 = 57 MPa
At F= 15100 N , = 15100 / (12.8/2)2 = 117.4 MPa
Then, we can do the same calculations for the resting loads to find their stresses
=
∆𝐿
𝐿𝑖
, when F=0, so no change in length will be occurred ∆𝐿=0 and =0
F= 7330, =
50.851−50.8
50.8
= 0.001
F= 15100, =
50.902−50.8
50.8
= 0.002
Then, we can do the same calculations for the resting loads to find their strain
26.
27. (b) The elastic modulus is the slope in the linear elastic region
E = ∆
∆
=
200 𝑀𝑃𝑎−0 𝑀𝑃𝑎
0.0032−0
= 62.5 x103 MPa = 62.5 GPa
(c) For the yield strength, the 0.002 strain offset line is drawn dashed. It
intersects the stress–strain curve at approximately 285 MPa.
(d) The tensile strength is approximately 370 MPa, corresponding to
the maximum stress on the complete stress-strain plot.
(e) % EL=
𝐿𝑓−𝐿𝑖
𝐿𝑖
x 100 =
59.1−50.8
50.8
x100 = 16.33 %
28. Example 5 :
For some metal alloy, a true stress of 345 MPa produces a plastic true strain of 0.02. How much will a specimen of this
material elongate when a true stress of 415 MPa is applied if the original length is 500 mm? Assume a value of 0.22 for the
strain-hardening exponent, n.
σT = K (εT) n
Next we must solve for the true strain produce when a true stress of 415 MPa is applied