Tensile Testing. Objectives

Size: px
Start display at page:

Download "Tensile Testing. Objectives"

Transcription

1 Laboratory 1 Tensile Testing Objectives Students are required to understand the principle of a uniaxial tensile testing and gain their practices on operating the tensile testing machine. Students are able to explain load-extension and stress-strain relationships. To evaluate the values of ultimate tensile strength, yield strength, % elongation, fracture strain and Young s Modulus of the selected metals when subjected to uniaxial tensile loading. Students can explain deformation and fracture characteristics of different materials such as aluminium, steels or brass when subjected to uniaxial tensile loading. Mechanical metallurgy laboratory

2 1. Literature Review 1.1 Stress and strain relationship Uniaxial tensile test is known as a basic engineering test to achieve ultimate strength, yield strength and ductility of interested materials. These important parameters are useful for the selection of engineering materials for any applications required. A standard specimen is prepared in a round or a square section along the gauge length as shown in figures 1 a) and b) respectively, depending on the standard used. Both ends of the specimens should have sufficient length and a surface condition such that they are firmly gripped during testing. The initial gauge length L o is standardized (in several countries) and varies with the diameter (D o ) or the cross-sectional area (A o ) of the specimen as listed in table 1. This is because if the gauge length is too long, the % elongation might be underestimated in this case. Any heat treatments should be applied on to the specimen prior to machining to produce the final specimen readily for testing. This has been done to prevent surface oxide scales that might act as stress concentration which might subsequently affect the final tensile properties due to premature failure. There might be some exceptions, for examples, surface hardening or surface coating on the materials. These processes should be employed after specimen machining in order to obtain the tensile properties results which include the actual specimen surface conditions. Figure 1: Standard tensile specimens Type specimen United State (ASTM) Great Britain Germany Sheet L / A ) ( o o Rod L / D ) ( o o Table 1: Dimensional relationships of tensile specimens used in various countries. Mechanical metallurgy laboratory

3 When a specimen is subjected to a tensile loading, the metal will undergo elastic and plastic deformation. Initially, the metal will elastically deform giving a linear relationship of load and extension. These two parameters are then used for the calculation of the engineering stress and engineering strain to give a relationship as illustrated in figure 2 using equations 1 and 2 as follow P σ = (1) A o L L f o ε = = (2) L o L L o where σ is the engineering stress ε is the engineering strain P is the external tensile load A o is the original cross-sectional area of the specimen L o is the original length of the specimen is the final length of the specimen L f During elastic deformation, the engineering stress-strain relationship follows the Hook s Law and the slope of the curve indicates the Young s modulus (E) σ E = ε (3) If the tensile loading continues, yielding occurs at the beginning of plastic deformation. The yield stress, σ y, can be obtained by dividing the load at yielding (P y ) by the original cross-sectional area of the specimen (A o ) as shown in equation 4. P y σ y = (4) Ao Mechanical metallurgy laboratory

4 Figure 2: Stress-strain relationship under uniaxial tensile loading The yield point can be observed directly from the load-extension curve of the BCC metals such as iron and steel or in polycrystalline titanium and molybdenum, and especially low carbon steels, see figure 3 a). The yield point elongation phenomenon shows the upper yield point followed by a sudden reduction in the stress or load till reaching the lower yield point. At the yield point elongation, the specimen continues to extend without a significant change in the stress level. Load increment is then followed with increasing strain. This yield point phenomenon is associated with a small amount of interstitial or substitutional atoms. This is for example in the case of low-carbon steels, which have small atoms of carbon and nitrogen present as impurities. When the dislocations are pinned by these solute atoms, the stress is raised in order to overcome the breakaway stress required for the pulling of dislocation line from the solute atoms. This dislocation pinning is related to the upper yield point as indicated in figure 3 a). If the dislocation line is free from the solute atoms, the stress required to move the dislocations then suddenly drops, which is associated with the lower yield point. Furthermore, it was found that the degree of the yield point effect is affected by the amounts of the solute atoms and is also influenced by the interaction energy between the solute atoms and the dislocations. Mechanical metallurgy laboratory

5 Aluminium on the other hand having a FCC crystal structure does not show the definite yield point in comparison to those of the BCC structure materials, but shows a smooth engineering stressstrain curve. The yield strength therefore has to be calculated from the load at 0.2% strain divided by the original cross-sectional area as follows P 0.2% 0.2% y = Ao σ...(5) Note: the yield strength values can also be obtained at 0.5 and 1.0% strain. The determination of the yield strength at 0.2% offset or 0.2% strain can be carried out by drawing a straight line parallel to the slope of the stress-strain curve in the linear section, having an intersection on the x-axis at a strain equal to as illustrated in figure 3 b). An interception between the 0.2% offset line and the stress-strain curve represents the yield strength at 0.2% offset or 0.2% strain. Figure 3: a) Comparative stress-strain relationships of low carbon steel and aluminium alloy and b) the determination of the yield strength at 0.2% offset. Mechanical metallurgy laboratory

6 Beyond yielding, continuous loading leads to an increase in the stress required to permanently deform the specimen as shown in the engineering stress-strain curve. At this stage, the specimen is strain hardened or work hardened. The degree of strain hardening depends on the nature of the deformed materials, crystal structure and chemical composition, which affects the dislocation motion. FCC structure materials having a high number of operating slip systems can easily slip and create a high density of dislocations. Tangling of these dislocations requires higher stress to uniformly and plastically deform the specimen, therefore resulting in strain hardening. If the load is continuously applied, the stress-strain curve will reach the maximum point, which is the ultimate tensile strength (UTS, σ TS ). At this point, the specimen can withstand the highest stress before necking takes place. This can be observed by a local reduction in the crosssectional area of the specimen generally observed in the centre of the gauge length as illustrated in figure 4. After necking, plastic deformation is not uniform and the stress decreases accordingly until fracture. The fracture strength (σ fracture ) can be calculated from the load at fracture divided by the original cross-sectional area, A o, as expressed in equation 6. P fracture σ fracture = (6) Ao Figure 4: Necking of a tensile specimen occurring prior to fracture Tensile ductility of the specimen can be represented as % elongation or % reduction in area as expressed in the equations given below L % Elongation = 100 (7) L o Mechanical metallurgy laboratory

7 % RA = A A A A 100 = 100 A o f (8) o 0 where A f is the cross-sectional area of specimen at fracture. The fracture strain of the specimen can be obtained by drawing a straight line starting at the fracture point of the stress-strain curve parallel to the slope in the linear relation. The interception of the parallel line at the x axis indicates the fracture strain of the specimen being tested. 1.2 Fracture characteristics of the tested specimens Metals with good ductility normally exhibit a so-called cup and cone fracture observed on either halves of a broken specimen as illustrated in figure 5. Necking starts when the stress-strain curve has passed the maximum point where plastic deformation is no longer uniform. Across the necking area within the specimen gauge length (normally located in the middle), microvoids are formed, enlarged and then merged to each other as the load is increased. This creates a crack having a plane perpendicular to the applied tensile stress. Just before the specimen breaks, the shear plane of approximately 45 o to the tensile axis is formed along the peripheral of the specimen. This shear plane then joins with the former crack to generate the cup and cone fracture as demonstrated in figure 5. The rough or fibrous fracture surfaces appear in grey by naked eyes. Under SEM, copious amounts of microvoids are observed as depicted in figure 6. This type of fracture surface signifies high energy absorption during the fracture process due to large amount of plastic deformation taking place, also indicating good tensile ductility. For brittle metals or metals that failed at relatively low temperatures, the fracture surfaces usually appear bright and consist of flat areas of brittle facets when examined under SEM as illustrated in figure 7. In some cases, clusters of these brittle facets are visible when the grain size of the metal is sufficiently large. The energy absorption is quite small in this case which indicates relatively low tensile ductility due to limited amount of plastic deformation. Mechanical metallurgy laboratory

8 Figure 5: Cup and cone fracture [3] Figure 6: Ductile fracture surface (Ductile metals) Figure 7: Brittle fracture surface (Brittle metals) Mechanical metallurgy laboratory

9 2. Materials and equipment 2.1 Tensile specimens 2.2 Micrometer or vernia calipers 2.3 Universal testing machine 3. Experimental procedure 3.1 The specimens provided are made of aluminium, steel and brass. Measure and record specimen dimensions (diameter and gauge length) in a table provided for the calculation of the engineering stress and engineering strain. Marking the location of the gauge length along the parallel length of each specimen for subsequent observation of necking and strain measurement. 3.2 Fit the specimen on to the universal Testing Machine (UTM) and carry on testing. Record load and extension for the construction of stress-strain curve of each tested specimen. 3.3 Calculate Young s modulus, yield strength, ultimate tensile strength, fracture strain and % elongation of each specimen and record on the provided table. 3.4 Analyze the fracture surfaces of broken specimens and sketch and describe the results 3.5 Discuss the experimental results and give conclusions. Mechanical metallurgy laboratory

10 4. Results Details Aluminium Steel Brass Diameter (mm) Width (mm) Thickness (mm) Cross-sectional area (mm 2 ) Gauge length (mm) Young s modulus (GPa) Load at yield point (N) Yield strength (MPa) Maximum load (N) Ultimate tensile strength (MPa) % Elongation Fracture strain Work hardening exponent (n) Fracture mode Fracture surfaces (Sketch) Table 2: Experimental data for tensile testing. Mechanical metallurgy laboratory

11 Engineering stress-strain curve of aluminium Describe the engineering stress-strain curve Mechanical metallurgy laboratory

12 Engineering stress-strain curve of steel Describe the engineering stress-strain curve Mechanical metallurgy laboratory

13 Engineering stress-strain curve of brass Describe the engineering stress-strain curve Mechanical metallurgy laboratory

14 5. Discussion Mechanical metallurgy laboratory

15 6. Conclusions Mechanical metallurgy laboratory

16 7. Questions 7.1 What is work hardening exponent (n)? How is this value related to the ability of metal to be mechanically formed? 7.2 If the tensile specimen is not cylindrical rod shaped but a flat rectangular plate, how do you expect necking to occur in this type of specimen? Mechanical metallurgy laboratory

17 7.3 Both yield strength and ultimate tensile strength exhibit the ability of a material to withstand a certain level of load. Which parameter do you prefer to use as a design parameter for a proper selection of materials for structural applications? Explain 8. References 8.1 Hashemi, S. Foundations of materials science and engineering, 2006, 4 th edition, McGraw- Hill, ISBN Dieter, G.E., Mechanical metallurgy, 1988, SI metric edition, McGraw-Hill, ISBN W.D. Callister, Fundamental of materials science and engineering/an interactive e. text, 2001, John Willey & Sons, Inc., New York, ISBN x. Mechanical metallurgy laboratory

Fatigue Testing. Objectives

Fatigue Testing. Objectives Laboratory 8 Fatigue Testing Objectives Students are required to understand principle of fatigue testing as well as practice how to operate the fatigue testing machine in a reverse loading manner. Students

More information

ME 105 Mechanical Engineering Laboratory Spring Quarter Tensile Test

ME 105 Mechanical Engineering Laboratory Spring Quarter Tensile Test ME 105 Mechanical Engineering Lab Page 1 ME 105 Mechanical Engineering Laboratory Spring Quarter 2003 3. Tensile Test Introduction In this lab, you will study the deformation and fracture characteristics

More information

MAE 20 Winter 2011 Assignment 5

MAE 20 Winter 2011 Assignment 5 MAE 20 Winter 2011 Assignment 5 6.7 For a bronze alloy, the stress at which plastic deformation begins is 275 MPa (40,000 psi), and the modulus of elasticity is 115 GPa (16.7 10 6 psi). (a) What is the

More information

There are three principle ways a load can be applied:

There are three principle ways a load can be applied: MATERIALS SCIENCE Concepts of Stress and Strains Stress-strain test is used to determine the mechanical behavior by applying a static load uniformly over a cross section or a surface of a member. The test

More information

Torsion Testing. Objectives

Torsion Testing. Objectives Laboratory 4 Torsion Testing Objectives Students are required to understand the principles of torsion testing, practice their testing skills and interpreting the experimental results of the provided materials

More information

Adam Zaborski handouts for Afghans

Adam Zaborski handouts for Afghans Tensile test Adam Zaborski handouts for Afghans Outline Tensile test purpose Universal testing machines and test specimens Stress-strain diagram Mild steel : proportional stage, elastic limit, yielding

More information

Tensile Testing Laboratory

Tensile Testing Laboratory Tensile Testing Laboratory By Stephan Favilla 0723668 ME 354 AC Date of Lab Report Submission: February 11 th 2010 Date of Lab Exercise: January 28 th 2010 1 Executive Summary Tensile tests are fundamental

More information

MSE200 Lecture 7 (CH ) Mechanical Properties I Instructor: Yuntian Zhu Objectives/outcomes: You will learn the following:

MSE200 Lecture 7 (CH ) Mechanical Properties I Instructor: Yuntian Zhu Objectives/outcomes: You will learn the following: MSE200 Lecture 7 (CH. 6.2-6.4) Mechanical Properties I Instructor: Yuntian Zhu Objectives/outcomes: You will learn the following: Stresses and strains in solids. Normal and shear stresses. Elastic and

More information

Griffith theory of brittle fracture:

Griffith theory of brittle fracture: Griffith theory of brittle fracture: Observed fracture strength is always lower than theoretical cohesive strength. Griffith explained that the discrepancy is due to the inherent defects in brittle materials

More information

PLASTIC DEFORMATION AND STRESS-STRAIN CURVES

PLASTIC DEFORMATION AND STRESS-STRAIN CURVES PLASTIC DEFORMATION AND STRESS-STRAIN CURVES Introduction Background Unit: Plastic Deformation and Stress-Strain Curves In the last unit we studied the elastic response of materials to externally applied

More information

Stress Strain Relationships

Stress Strain Relationships Stress Strain Relationships Tensile Testing One basic ingredient in the study of the mechanics of deformable bodies is the resistive properties of materials. These properties relate the stresses to the

More information

Mechanical Properties

Mechanical Properties Mechanical Properties Hardness Hardness can be defined as resistance to deformation or indentation or resistance to scratch. Hardness Indentation Scratch Rebound Indentation hardness is of particular interest

More information

Introduction to Structure and Properties Winter 2005 Final Exam March 17, 2005 TOTAL POINTS 37

Introduction to Structure and Properties Winter 2005 Final Exam March 17, 2005 TOTAL POINTS 37 Materials 101 Introduction to Structure and Properties Winter 005 Final Exam March 17, 005 Solutions TOTAL POINTS 37 Problem 1: Tensile Test and Plastic Deformation (10 Points) A copper rod is deformed

More information

METU DEPARTMENT OF METALLURGICAL AND MATERIALS ENGINEERING

METU DEPARTMENT OF METALLURGICAL AND MATERIALS ENGINEERING METU DEPARTMENT OF METALLURGICAL AND MATERIALS ENGINEERING Met E 206 MATERIALS LABORATORY EXPERIMENT 1 Prof. Dr. Rıza GÜRBÜZ Res. Assist. Gül ÇEVİK (Room: B-306) INTRODUCTION TENSION TEST Mechanical testing

More information

ME 215 Engineering Materials I

ME 215 Engineering Materials I ME 215 Engineering Materials I Chapter 3 Properties in Tension and Compression (Part III) Mechanical Engineering University of Gaziantep Dr. A. Tolga Bozdana www.gantep.edu.tr/~bozdana True Stress and

More information

Review from Mechanical Properties of Materials

Review from Mechanical Properties of Materials Fall 24 Review from Mechanical Properties of Materials Concept of Stress and Strain Figure 1 shows the behavior of a clindrical bod subjected to tension and compression. Tension specimen etends along its

More information

Objectives. Experimentally determine the yield strength, tensile strength, and modules of elasticity and ductility of given materials.

Objectives. Experimentally determine the yield strength, tensile strength, and modules of elasticity and ductility of given materials. Lab 3 Tension Test Objectives Concepts Background Experimental Procedure Report Requirements Discussion Objectives Experimentally determine the yield strength, tensile strength, and modules of elasticity

More information

MECHANICAL PROPERTIES OF MATERIALS. IE-114 Materials Science and General Chemistry Lecture-6

MECHANICAL PROPERTIES OF MATERIALS. IE-114 Materials Science and General Chemistry Lecture-6 MECHANICAL PROPERTIES OF MATERIALS IE-114 Materials Science and General Chemistry Lecture-6 Overview 1) ELASTIC DEFORMATION - Elastic Behavior - Anelasticity - Elastic Properties of Materials 2) PLASTIC

More information

MSE 527L - Testing of Materials in Tension

MSE 527L - Testing of Materials in Tension MSE 527L - Testing of Materials in Tension Object: The object of this experiment is to measure the tensile properties of steel, copper and aluminum at a constant strain rate on the tension testing machine

More information

σ = F / A o Chapter Outline Introduction Mechanical Properties of Metals How do metals respond to external loads?

σ = F / A o Chapter Outline Introduction Mechanical Properties of Metals How do metals respond to external loads? Mechanical Properties of Metals How do metals respond to external loads? and Tension Compression Shear Torsion Elastic deformation Chapter Outline Introduction To understand and describe how materials

More information

CHAPTER 6 MECHANICAL PROPERTIES OF METALS PROBLEM SOLUTIONS

CHAPTER 6 MECHANICAL PROPERTIES OF METALS PROBLEM SOLUTIONS CHAPTER 6 MECHANICAL PROPERTIES OF METALS PROBLEM SOLUTIONS Concepts of Stress and Strain 6.1 Using mechanics of materials principles (i.e., equations of mechanical equilibrium applied to a free-body diagram),

More information

Stress-Strain Relationship

Stress-Strain Relationship (Strength of Materials) Dave Morgan Stress-Strain Relationship p. 1/21 The tension test: Stress-Strain Relationship p. 2/21 The tension test: Is a common standardised test that can

More information

(10 4 mm -2 )(1000 mm 3 ) = 10 7 mm = 10 4 m = 6.2 mi

(10 4 mm -2 )(1000 mm 3 ) = 10 7 mm = 10 4 m = 6.2 mi 14:440:407 Fall 010 Additional problems and SOLUTION OF HOMEWORK 07 DISLOCATIONS AND STRENGTHENING MECHANISMS PROBLEM SOLUTIONS Basic Concepts of Dislocations Characteristics of Dislocations 7.1 To provide

More information

Mechanical Properties of Metals Mechanical Properties refers to the behavior of material when external forces are applied

Mechanical Properties of Metals Mechanical Properties refers to the behavior of material when external forces are applied Mechanical Properties of Metals Mechanical Properties refers to the behavior of material when external forces are applied Stress and strain fracture or engineering point of view: allows to predict the

More information

Hardness Testing. Objectives

Hardness Testing. Objectives Laboratory 2 Hardness Testing Objectives Students are required to understand the principles of hardness testing, i.e., Rockwell, Brinell and Vickers hardness tests. Students are able to explain variations

More information

Brittle fracture and impact tests

Brittle fracture and impact tests Brittle fracture and impact tests Subjects of interest Chapter 12 Objective The brittle-fracture problem Notch-bar impact tests Ductile to metal transition temperature curve Metallurgical factors affecting

More information

Plastic Behaviour - Tensile Strength

Plastic Behaviour - Tensile Strength Plastic Behaviour - Tensile Strength Transition of mechanical behaviour from elastic to plastic depends upon the material type and its condition as tested (hot-rolled, cold-rolled, heat treated, etc.).

More information

Chapter Outline. Mechanical Properties of Metals How do metals respond to external loads?

Chapter Outline. Mechanical Properties of Metals How do metals respond to external loads? Mechanical Properties of Metals How do metals respond to external loads? Stress and Strain Tension Compression Shear Torsion Elastic deformation Plastic Deformation Yield Strength Tensile Strength Ductility

More information

Question 6.5: A steel bar 100 mm (4.0 in.) long and having a square cross section 20 mm

Question 6.5: A steel bar 100 mm (4.0 in.) long and having a square cross section 20 mm 14:440:407 Ch6 Question 6.3: A specimen of aluminum having a rectangular cross section 10 mm 12.7 mm (0.4 in. 0.5 in.) is pulled in tension with 35,500 N (8000 lb f ) force, producing only elastic deformation.

More information

Mechanical properties laboratory practice guide 2015

Mechanical properties laboratory practice guide 2015 Mechanical properties laboratory practice guide 215 Hardness test methods Hardness is resistance of material to plastic deformation caused by indentation. 1. Brinell Hardness Test [1] Dr. J. A. Brinell

More information

Section 1: THE TEST CERTIFICATE

Section 1: THE TEST CERTIFICATE Section 1: THE TEST CERTIFICATE The objective of Section 1 is to explain the Metallurgical makeup of the Material Test Certificate. Introduction A material test certificate is used to report the chemical

More information

Statics and Mechanics of Materials

Statics and Mechanics of Materials Statics and Mechanics of Materials Chapter 4 Stress, Strain and Deformation: Axial Loading Objectives: Learn and understand the concepts of internal forces, stresses, and strains Learn and understand the

More information

Chapter Outline Dislocations and Strengthening Mechanisms

Chapter Outline Dislocations and Strengthening Mechanisms Chapter Outline Dislocations and Strengthening Mechanisms What is happening in material during plastic deformation? Dislocations and Plastic Deformation Motion of dislocations in response to stress Slip

More information

Concepts of Stress and Strain

Concepts of Stress and Strain CHAPTER 6 MECHANICAL PROPERTIES OF METALS PROBLEM SOLUTIONS Concepts of Stress and Strain 6.4 A cylindrical specimen of a titanium alloy having an elastic modulus of 107 GPa (15.5 10 6 psi) and an original

More information

Uniaxial Tension and Compression Testing of Materials. Nikita Khlystov Daniel Lizardo Keisuke Matsushita Jennie Zheng

Uniaxial Tension and Compression Testing of Materials. Nikita Khlystov Daniel Lizardo Keisuke Matsushita Jennie Zheng Uniaxial Tension and Compression Testing of Materials Nikita Khlystov Daniel Lizardo Keisuke Matsushita Jennie Zheng 3.032 Lab Report September 25, 2013 I. Introduction Understanding material mechanics

More information

BEYOND ELASTICITY. Sub-topics. Plasticity Toughness Hardness Design problems

BEYOND ELASTICITY. Sub-topics. Plasticity Toughness Hardness Design problems BEYOND ELASTICITY Sub-topics 1 Plasticity Toughness Hardness Design problems PLASTICITY The stress is no longer proportional to strain 2 STRESS-STRAIN BEHAVIOR: PLASTICITY Tensile strength is the stress

More information

MCEN 2024, Spring 2008 The week of Apr 07 HW 9 with Solutions

MCEN 2024, Spring 2008 The week of Apr 07 HW 9 with Solutions MCEN 2024, Spring 2008 The week of Apr 07 HW 9 with Solutions The Quiz questions based upon HW9 will open on Thursday, Apr. 11 and close on Wednesday, Apr 17 at 1:30 PM. References to A&J: Chapters 13,

More information

CHAPTER 7 DISLOCATIONS AND STRENGTHENING MECHANISMS PROBLEM SOLUTIONS

CHAPTER 7 DISLOCATIONS AND STRENGTHENING MECHANISMS PROBLEM SOLUTIONS 7-1 CHAPTER 7 DISLOCATIONS AND STRENGTHENING MECHANISMS PROBLEM SOLUTIONS Basic Concepts of Dislocations Characteristics of Dislocations 7.1 The dislocation density is just the total dislocation length

More information

Chapter 4 Strain and Material Relations

Chapter 4 Strain and Material Relations CIVL 222 STRENGTH OF MATERIALS Chapter 4 Strain and Material Relations Terminology 1. Displacement 2. Deformation 3. Strain 4. Average Axial Strain 5. Shearing Strain 6. Poisson s Ratio 7. Mechanical Properties

More information

σ y ( ε f, σ f ) ( ε f

σ y ( ε f, σ f ) ( ε f Typical stress-strain curves for mild steel and aluminum alloy from tensile tests L L( 1 + ε) A = --- A u u 0 1 E l mild steel fracture u ( ε f, f ) ( ε f, f ) ε 0 ε 0.2 = 0.002 aluminum alloy fracture

More information

LABORATORY EXPERIMENTS TESTING OF MATERIALS

LABORATORY EXPERIMENTS TESTING OF MATERIALS LABORATORY EXPERIMENTS TESTING OF MATERIALS 1. TENSION TEST: INTRODUCTION & THEORY The tension test is the most commonly used method to evaluate the mechanical properties of metals. Its main objective

More information

Chapter Outline. Mechanical Properties of Metals How do metals respond to external loads?

Chapter Outline. Mechanical Properties of Metals How do metals respond to external loads? Mechanical Properties of Metals How do metals respond to external loads? Stress and Strain Tension Compression Shear Torsion Elastic deformation Plastic Deformation Yield Strength Tensile Strength Ductility

More information

Chapter Outline Dislocations and Strengthening Mechanisms

Chapter Outline Dislocations and Strengthening Mechanisms Chapter Outline Dislocations and Strengthening Mechanisms What is happening in material during plastic deformation? Dislocations and Plastic Deformation Motion of dislocations in response to stress Slip

More information

Mechanics of Materials-Steel

Mechanics of Materials-Steel Mechanics of Materials-Steel Structural Steel Structural steel considered one of the predominant materials for construction of buildings, bridges, towers and other structures. The preferable physical properties

More information

Fatigue :Failure under fluctuating / cyclic stress

Fatigue :Failure under fluctuating / cyclic stress Fatigue :Failure under fluctuating / cyclic stress Under fluctuating / cyclic stresses, failure can occur at loads considerably lower than tensile or yield strengths of material under a static load: Fatigue

More information

Tensile Testing of Nanoscale and Macroscale Metal Samples

Tensile Testing of Nanoscale and Macroscale Metal Samples Tensile Testing of Nanoscale and Macroscale Metal Samples Instructions and Safety: Please read this lab handout and the required background reading before the Monday pre-lab lecture. You should also review

More information

STRAIN-LIFE (e -N) APPROACH

STRAIN-LIFE (e -N) APPROACH CYCLIC DEFORMATION & STRAIN-LIFE (e -N) APPROACH MONOTONIC TENSION TEST AND STRESS-STRAIN BEHAVIOR STRAIN-CONTROLLED TEST METHODS CYCLIC DEFORMATION AND STRESS-STRAIN BEHAVIOR STRAIN-BASED APPROACH TO

More information

1.103 CIVIL ENGINEERING MATERIALS LABORATORY (1-2-3) Dr. J.T. Germaine Spring 2004 TENSILE TESTING AND STRESS STRAIN PROPERTIES OF STEEL

1.103 CIVIL ENGINEERING MATERIALS LABORATORY (1-2-3) Dr. J.T. Germaine Spring 2004 TENSILE TESTING AND STRESS STRAIN PROPERTIES OF STEEL 1.103 CIVIL ENGINEERING MATERIALS LABORATORY (1-2-3) Dr. J.T. Germaine MIT Spring 2004 Purpose: LABORATORY ASSIGNMENT NUMBER 2 TENSILE TESTING AND STRESS STRAIN PROPERTIES OF STEEL You will learn about:

More information

Material Strengthening Mechanisms. Academic Resource Center

Material Strengthening Mechanisms. Academic Resource Center Material Strengthening Mechanisms Academic Resource Center Agenda Definition of strengthening Strengthening mechanisms Grain size reduction Solid solution alloying Cold Working (strain hardening) Three

More information

Tensile Testing of Steel

Tensile Testing of Steel C 265 Lab No. 2: Tensile Testing of Steel See web for typical report format including: TITL PAG, ABSTRACT, TABL OF CONTNTS, LIST OF TABL, LIST OF FIGURS 1.0 - INTRODUCTION See General Lab Report Format

More information

MUKAVEMET KIRILMA HİPOTEZLERİ

MUKAVEMET KIRILMA HİPOTEZLERİ 1 MUKAVEMET KIRILMA HİPOTEZLERİ 17. Theories of failure or yield criteria (1) Maximum shearing stress theory (2) Octahedral shearing stress theory (3) Maximum normal stress theory for brittle materials.

More information

CHAPTER 4 TENSILE TESTING

CHAPTER 4 TENSILE TESTING CHAPTER 4 TENSILE TESTING EXERCISE 28, Page 7 1. What is a tensile test? Make a sketch of a typical load/extension graph for a mild steel specimen to the point of fracture and mark on the sketch the following:

More information

Objective To conduct Charpy V-notch impact test and determine the ductile-brittle transition temperature of steels.

Objective To conduct Charpy V-notch impact test and determine the ductile-brittle transition temperature of steels. IMPACT TESTING Objective To conduct Charpy V-notch impact test and determine the ductile-brittle transition temperature of steels. Equipment Coolants Standard Charpy V-Notched Test specimens Impact tester

More information

Structures and Stiffness

Structures and Stiffness Structures and Stiffness ENGR 10 Introduction to Engineering Ken Youssefi/Thalia Anagnos Engineering 10, SJSU 1 Wind Turbine Structure The Goal The support structure should be optimized for weight and

More information

Experiment: Mechanical Testing- Tensile Testing

Experiment: Mechanical Testing- Tensile Testing Experiment: Mechanical Testing- Tensile Testing Objective The primary objective of this investigation is to conduct a standard tensile test for determining the stress-strain behavior of a material sample

More information

Mechanical properties 3 Bend test and hardness test of materials

Mechanical properties 3 Bend test and hardness test of materials MME131: Lecture 15 Mechanical properties 3 Bend test and hardness test of materials A. K. M. B. Rashid Professor, Department of MME BUET, Dhaka Today s Topics Bend test of brittle materials Hardness testing

More information

Pin jointed structures are often used because they are simple to design, relatively inexpensive to make, easy to construct, and easy to modify.

Pin jointed structures are often used because they are simple to design, relatively inexpensive to make, easy to construct, and easy to modify. 4. FORCES in PIN JOINTED STRUCTURES Pin jointed structures are often used because they are simple to design, relatively inexpensive to make, easy to construct, and easy to modify. They can be fixed structures

More information

SAMPLE OF THE STUDY MATERIAL PART OF CHAPTER 1 STRESS AND STRAIN

SAMPLE OF THE STUDY MATERIAL PART OF CHAPTER 1 STRESS AND STRAIN SAMPLE OF THE STUDY MATERIAL PART OF CHAPTER 1 STRESS AND STRAIN 1.1 Stress & Strain Stress is the internal resistance offered by the body per unit area. Stress is represented as force per unit area. Typical

More information

Material Types and Properties

Material Types and Properties Material Types and Properties 1 Material Types There are many kinds of materials, but most of them can be divided into four groups: Metals - Metals are composed of one or more metallic elements and often

More information

Strength and Stiffness

Strength and Stiffness Strength and Stiffness Stress = load/area is applied to a material by loading it Strain = deformation/length a change of shape (dimensions and twist angles) is its response Stiffness = stress/strain is

More information

FAILURE MODES and MATERIALS PROPERTIES. Component failures. Ductile and Brittle Fracture COMPONENT FAILURES. COMPONENT FAILURE MODES examples:

FAILURE MODES and MATERIALS PROPERTIES. Component failures. Ductile and Brittle Fracture COMPONENT FAILURES. COMPONENT FAILURE MODES examples: FAILURE MODES and MATERIALS PROPERTIES MECH2300 - Materials Lecture 10 R. W. Truss Materials Engineering R.Truss@uq.edu.au COMPONENT FAILURES Structures lectures es on component es cause response in component

More information

Mechanical Metallurgy

Mechanical Metallurgy Mechanical Metallurgy Lecturer Assessment Dr. Assignment 20 (homework, quiz, attendance) Midterm exam 40 Final exam 40 Total 100 Mechanical Metallurgy Subject of interests Part I Mechanical fundamentals

More information

Problem P5.2: A 1 Mg container hangs from a 15 mm diameter steel cable. What is the stress in the cable?

Problem P5.2: A 1 Mg container hangs from a 15 mm diameter steel cable. What is the stress in the cable? Problem P5.: A 1 Mg container hangs from a 15 mm diameter steel cable. What is the stress in the cable? Find the cross sectional area in terms of diameter using Equation (5.1). Calculate the tensile stress

More information

ME 388 APPLIED INSTUMENTATION LAB Mechanical Properties by Tensile Testing

ME 388 APPLIED INSTUMENTATION LAB Mechanical Properties by Tensile Testing 1 Prepared 6/27/08 by Dr. Kraft Learning Objectives 1. To learn fundamentals of tensile testing to determine basic mechanical properties of materials. 2. To analyze tensile test data to analytically model

More information

Material Deformations. Academic Resource Center

Material Deformations. Academic Resource Center Material Deformations Academic Resource Center Agenda Origin of deformations Deformations & dislocations Dislocation motion Slip systems Stresses involved with deformation Deformation by twinning Origin

More information

Solution for Homework #1

Solution for Homework #1 Solution for Homework #1 Chapter 2: Multiple Choice Questions (2.5, 2.6, 2.8, 2.11) 2.5 Which of the following bond types are classified as primary bonds (more than one)? (a) covalent bonding, (b) hydrogen

More information

Properties of Materials

Properties of Materials CHAPTER 1 Properties of Materials INTRODUCTION Materials are the driving force behind the technological revolutions and are the key ingredients for manufacturing. Materials are everywhere around us, and

More information

Constitutive Equations - Plasticity

Constitutive Equations - Plasticity MCEN 5023/ASEN 5012 Chapter 9 Constitutive Equations - Plasticity Fall, 2006 1 Mechanical Properties of Materials: Modulus of Elasticity Tensile strength Yield Strength Compressive strength Hardness Impact

More information

(10 4 mm -2 )(1000 mm 3 ) = 10 7 mm = 10 4 m = 6.2 mi

(10 4 mm -2 )(1000 mm 3 ) = 10 7 mm = 10 4 m = 6.2 mi CHAPTER 8 DEFORMATION AND STRENGTHENING MECHANISMS PROBLEM SOLUTIONS Basic Concepts of Dislocations Characteristics of Dislocations 8.1 To provide some perspective on the dimensions of atomic defects,

More information

TENSILE TESTING PRACTICAL

TENSILE TESTING PRACTICAL TENSILE TESTING PRACTICAL MTK 2B- Science Of Materials Ts epo Mputsoe 215024596 Summary Material have different properties all varying form mechanical to chemical properties. Taking special interest in

More information

CH 6: Fatigue Failure Resulting from Variable Loading

CH 6: Fatigue Failure Resulting from Variable Loading CH 6: Fatigue Failure Resulting from Variable Loading Some machine elements are subjected to static loads and for such elements static failure theories are used to predict failure (yielding or fracture).

More information

Sheet metal operations - Bending and related processes

Sheet metal operations - Bending and related processes Sheet metal operations - Bending and related processes R. Chandramouli Associate Dean-Research SASTRA University, Thanjavur-613 401 Table of Contents 1.Quiz-Key... Error! Bookmark not defined. 1.Bending

More information

Lecture 09 Dislocations & Strengthening Mechanisms

Lecture 09 Dislocations & Strengthening Mechanisms Lecture 09 Dislocations & Strengthening Mechanisms Chapter 7-1 Dislocations & Strengthening Mechanisms ISSUES TO ADDRESS... Why are dislocations observed primarily in metals and alloys? How are strength

More information

Torsion Tests. Subjects of interest

Torsion Tests. Subjects of interest Chapter 10 Torsion Tests Subjects of interest Introduction/Objectives Mechanical properties in torsion Torsional stresses for large plastic strains Type of torsion failures Torsion test vs.tension test

More information

PROPERTIES OF MATERIALS

PROPERTIES OF MATERIALS 1 PROPERTIES OF MATERIALS 1.1 PROPERTIES OF MATERIALS Different materials possess different properties in varying degree and therefore behave in different ways under given conditions. These properties

More information

Solid Mechanics. Stress. What you ll learn: Motivation

Solid Mechanics. Stress. What you ll learn: Motivation Solid Mechanics Stress What you ll learn: What is stress? Why stress is important? What are normal and shear stresses? What is strain? Hooke s law (relationship between stress and strain) Stress strain

More information

Structural materials Characteristics, testing, strength evaluation

Structural materials Characteristics, testing, strength evaluation Budapest University of Technology and Economics Department of Mechanics and Materials of Structures English courses General course /2013 Fundamentals of Structures BMEEPSTG201 Lecture no. 3: Structural

More information

Structural Nonlinearities

Structural Nonlinearities Lecture 5 Rate Independent Plasticity ANSYS Mechanical Structural Nonlinearities L5-1 ANSYS Mechanical Rate Independent Plasticity Chapter Overview The following will be covered in this Chapter: A. Background

More information

Table 1 Typical Physical and Thermal Properties of Mylar Polyester Film. Property Typical Value Unit Test Method

Table 1 Typical Physical and Thermal Properties of Mylar Polyester Film. Property Typical Value Unit Test Method Product Information Mylar polyester film Physical-Thermal Properties Mylar polyester film retains good physical properties over a wide temperature range ( 7 to 15 C [ 9 to 3 F]), and it is also used at

More information

Strength of Materials

Strength of Materials FE Review Strength of Materials Problem Statements Copyright 2008 C. F. Zorowski NC State E490 Mechanics of Solids 110 KN 90 KN 13.5 KN A 3 = 4.5x10-3 m 2 A 2 = 2x10-3 m 2 A 1 = 5x10-4 m 2 1. A circular

More information

Experiment: Mechanical Testing- Impact & Hardness Testing

Experiment: Mechanical Testing- Impact & Hardness Testing Experiment: Mechanical Testing- Impact & Hardness Testing Objective The main objective of this experiment is to introduce two important basic mechanical property tests; hardness (using Rockwell testing)

More information

Effect of Heat Treatment Processes on the Mechanical Properties of Medium Carbon Steel

Effect of Heat Treatment Processes on the Mechanical Properties of Medium Carbon Steel Journal of Minerals & Materials Characterization & Engineering, Vol. 11, No.2 pp.143-152, 2012 jmmce.org Printed in the USA. All rights reserved Effect of Heat Treatment Processes on the Mechanical Properties

More information

Figure 1: Typical S-N Curves

Figure 1: Typical S-N Curves Stress-Life Diagram (S-N Diagram) The basis of the Stress-Life method is the Wohler S-N diagram, shown schematically for two materials in Figure 1. The S-N diagram plots nominal stress amplitude S versus

More information

1. Steel fasteners for the temperature range between 50 C and +150 C

1. Steel fasteners for the temperature range between 50 C and +150 C 1. Steel fasteners for the temperature range between 50 C and +150 C 1.1 Materials for fasteners The material that is used is of decisive importance for the quality of the fasteners (screws, nuts and fittings).

More information

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA MECHANICAL PRINCIPLES OUTCOME 2 ENGINEERING COMPONENTS TUTORIAL 1 STRUCTURAL MEMBERS

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA MECHANICAL PRINCIPLES OUTCOME 2 ENGINEERING COMPONENTS TUTORIAL 1 STRUCTURAL MEMBERS ENGINEERING COMPONENTS EDEXCEL NATIONAL CERTIFICATE/DIPLOMA MECHANICAL PRINCIPLES OUTCOME ENGINEERING COMPONENTS TUTORIAL 1 STRUCTURAL MEMBERS Structural members: struts and ties; direct stress and strain,

More information

Material Testing Lab

Material Testing Lab Focus: Material Testing Lab This laboratory includes three separate materials testing experiments to be done on spaghetti of 3 different diameters. See individual labs for respective objectives. Students

More information

Experiment F: Failure Analysis

Experiment F: Failure Analysis Experiment F: Failure Analysis Introduction: In this experiment, a component that has failed in service will be analyzed to determine the probable cause or causes of the failure. Each group will give a

More information

Strength of materials

Strength of materials Strength of materials 1. General concepts All structures, both natural and man-made, are composed of materials that are arranged and assembled in a way that will fulfill the purpose of the structure. Buildings,

More information

MATERIALS SCIENCE AND ENGINEERING Vol. II Structural and Functional Materials - H. V. Atkinson STRUCTURAL AND FUNCTIONAL MATERIALS

MATERIALS SCIENCE AND ENGINEERING Vol. II Structural and Functional Materials - H. V. Atkinson STRUCTURAL AND FUNCTIONAL MATERIALS STRUCTURAL AND FUNCTIONAL MATERIALS H. V. Atkinson University of Sheffield, UK Keywords: Structural materials, functional materials, optical, electrical, dielectric, magnetic, thermal, elastic modulus,

More information

The atomic packing factor is defined as the ratio of sphere volume to the total unit cell volume, or APF = V S V C. = 2(sphere volume) = 2 = V C = 4R

The atomic packing factor is defined as the ratio of sphere volume to the total unit cell volume, or APF = V S V C. = 2(sphere volume) = 2 = V C = 4R 3.5 Show that the atomic packing factor for BCC is 0.68. The atomic packing factor is defined as the ratio of sphere volume to the total unit cell volume, or APF = V S V C Since there are two spheres associated

More information

MECHANICS OF MATERIALS

MECHANICS OF MATERIALS CHAPTER 2 MECHANICS OF MATERIALS Ferdinand P. Beer E. Russell Johnston, Jr. John T. DeWolf David F. Mazurek Lecture Notes: J. Walt Oler Texas Tech University Stress and Strain Axial Loading Normal Strain

More information

MECHANICAL PROPERTIES OF ENGINEERING MATERIALS

MECHANICAL PROPERTIES OF ENGINEERING MATERIALS MECHANICAL PROPERTIES OF ENGINEERING 1. Introduction MATERIALS Often materials are subject to forces (loads) when they are used. Mechanical engineers calculate those forces and material scientists how

More information

Deformation of Single Crystals

Deformation of Single Crystals Deformation of Single Crystals When a single crystal is deformed under a tensile stress, it is observed that plastic deformation occurs by slip on well defined parallel crystal planes. Sections of the

More information

PHYSICAL TEST OF STAINLESS STEEL 316 BETWEEN DIFFERENT MANUFACTURES

PHYSICAL TEST OF STAINLESS STEEL 316 BETWEEN DIFFERENT MANUFACTURES PHYSICAL TEST OF STAINLESS STEEL 316 BETWEEN DIFFERENT MANUFACTURES ZAITUL AQMAR BT MOHD ASRI Thesis submitted in partial fulfilment of the requirements for the award of the degree of Bachelor of Chemical

More information

8.1 Introduction to Plasticity

8.1 Introduction to Plasticity 8.1 Introduction to Plasticity 8.1.1 Introduction The theory of linear elasticity is useful for modelling materials which undergo small deformations and which return to their original configuration upon

More information

KINGS COLLEGE OF ENGINEERING DEPARTMENT OF MECHANICAL ENGINEERING QUESTION BANK. UNIT I STRESS STRAIN DEFORMATION OF SOLIDS PART- A (2 Marks)

KINGS COLLEGE OF ENGINEERING DEPARTMENT OF MECHANICAL ENGINEERING QUESTION BANK. UNIT I STRESS STRAIN DEFORMATION OF SOLIDS PART- A (2 Marks) KINGS COLLEGE OF ENGINEERING DEPARTMENT OF MECHANICAL ENGINEERING QUESTION BANK SUB CODE/NAME: CE1259 STRENGTH OF MATERIALS YEAR/SEM: II / IV 1. What is Hooke s Law? 2. What are the Elastic Constants?

More information

Hardness Test. Subjects of interest

Hardness Test. Subjects of interest Hardness Test Chapter 9 Subjects of interest Introduction/objectives Brinell hardness Meyer hardness Vickers hardness Rockwell hardness Microhardness tests Relationship between hardness and the flow curve

More information

HARDNESS TEST 1. OBJECT

HARDNESS TEST 1. OBJECT HARDNESS TEST 1. OBJECT The hardness test is a mechanical test for material properties which are used in engineering design, analysis of structures, and materials development. The principal purpose of

More information

Strength of materials

Strength of materials Strength of materials 1. General concepts All structures, both natural and man-made, are composed of materials that are arranged and assembled in a way that will fulfill the purpose of the structure. Buildings,

More information

Strength of Materials

Strength of Materials Strength of Materials 1. Strain is defined as the ratio of (a) change in volume to original volume (b) change in length to original length (c) change in cross-sectional area to original cross-sectional

More information