# Fatigue Testing. Objectives

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 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 are required to construct an S-N curve (stress level - number of cycles to failure) of the test samples provided. Students can define the fatigue endurance limit or fatigue life and fatigue strength of the materials. Students are able to interpret the obtained experimental results and use them as a tool for material selection in engineering applications. Mechanical Metallurgy Laboratory

3 - Maximum stress (σ max ) - Minimum stress (σ min ) - Stress range ( σ) = σ max σ min - Mean stress = (σ max + σ min )/2 - Stress amplitude = (σ max σ min )/2 - Stress ratio = σ min /σ max Figure 2: Relationships between stress and time or no. of cycles. These parameters significantly affect the fatigue behaviours of the materials. This is for example, increasing in the maximum stress as well as mean stress and stress range leads to more severe fatigue conditions. If the maximum and minimum stresses are tensile, they are considered to be more dangerous than compressive stresses as the tensile stresses will open up the fatigue crack. Furthermore, if the maximum and minimum stresses are in similar amounts but having the opposite signs (tensile and compressive stresses), the stresses in this case is called completely reversed cyclic stresses in which the stress ratio equals -1. For instance, a rotating-beam fatigue machine as shown in figure 3, fitted with a fatigue specimen hung by a weight in the middle. Specimen rotating action is driven by a motor on the right results in tensile stress in the lower fibrous and compressive stress in the upper fibrous of the specimen gauge length. Therefore, along the gauge length, specimen will be subjected to alternating tensile and compressive stresses similar to the reversed cyclic loading. The specimen will be fatigue loaded until failure. The number of cycles to failure according to the cyclic stress applied will then be recorded. Mechanical Metallurgy Laboratory

4 Figure 3: Rotating-beam fatigue testing machine [2]. The fatigue testing can also be conducted using an instrument as shown in figure 4. The fatigue specimen is gripped on to a motor at one end to provide the rotational motion whereas the other end is attached to a bearing and also subjected to a load or stress. When the specimen is rotated about the longitudinal axis, the upper and the lower parts of the specimen gauge length are subjected to tensile and compressive stresses respectively. Therefore, stress varies sinusoially at any point on the specimen surface. The test proceeds until specimen failure takes place. The revolution counter is used to obtain the number of cycles to failures corresponding to the stress applied. Figure 4: Fatigue testing machine [3]. Increasing of the weight applied to the fatigue specimen results in a reduction in number of cycles to failure. We can then use the experimental results to construct an S-N curve as illustrated in figure 5. The fatigue test is normally conducted using at least 8-12 specimens in order to provide sufficient information for the interpretation of fatigue behaviour of the tested material. The S-N curve shows a relationship between the applied stress and the number of cycles to failure, which can be used to determine the fatigue life of the material subjected to cyclic loading. High applied cyclic stress results in a low number of cycles to failure. For example, the fatigue testing of a 1047 steel provides a small number of cycles to failure at a high cyclic stress. As the cyclic stress reduces, the number of Mechanical Metallurgy Laboratory

5 cycles to failure increases. At the fatigue endurance limit, there will be a certain value of the cyclic stress where specimen failure will not occur. This cyclic stress level is called the fatigue strength. According to figure 4, the fatigue strength of 1047 steel is approximately 320 MPa. However, nonferrous alloys such as some alloys of aluminium, magnesium and copper will not normally show the fatigue endurance limit. The slope can be found gradually downwards with increasing number of cycles to failure and shows no horizontal line. In such a case, the fatigue strength will be defined at a stress level where the number of cycles to failure reaches 10 7 or 10 8 cycles. The fatigue strength of engineering materials is in general lower than their tensile strength. A ratio of the fatigue strength to the tensile strength as described in equation 1 is called the fatigue ratio. It is normally observed that, in the case of steels, the fatigue strength increases in proportional to the tensile stress. Therefore, improving the tensile strength by hardening or other heat treatments normally increases the fatigue strength of the mateiral. However for nonferrous metals such as aluminium alloys, the fatigue ratio is found approximately 0.3 and the improvement of the tensile strength do not necessary increases the fatigue strength of the material. Fatigue strength Fatigue ratio = (1) Tensile strength Figure 5: S-N curves of 1047 steel and 2014-T6 aluminium alloy[2]. Mechanical Metallurgy Laboratory

6 The fatigue S-N curve are generally considered in 2 cases, which are high cycle fatigue and low cycle fatigue. The study of high cycle fatigue concerns about fatigue behaviour of the materials which is controlled by the applied load or stress and where the gross deformation taking place is elastic. However highly localized plastic deformation can also be observed for example at the crack tip. The number of cycles to failure in this case is normally determined at higher than 10 5 cycles. The S-N curve in the high cycle fatigue region can be expressed using the Basquin equation as follow; N σ p = C (2) a where σ a is Stress amplitude p and C is Empirical constants In the case of low cycle fatigue, the fatigue behaviour is controlled by elastic and plastic strains and the number of cycles leading to failure is lower than 10 4 or 10 5 cycles. Gross plastic deformation is due to high levels of the applied stresses and leads to difficulties for stress interpretation. The low cycle fatigue data is generally presented as a relationship between plastic strain ( ε p ) and the number of cycles to failure (N) as illustrated in figure 6. When plotted in a log-log scale, the relationship can be expressed following the Coffin-Manson relationship ε 2 p = ε (2N) ' f c (3) where ε p /2 is Plastic strain amplitude ε f is Fatigue ductility coefficient 2N is Strain reversal to failure, whereby 1 cycle equals 2 reversals C is Fatigue ductility exponent, having the values ranging from -0.5 to 0.7. Mechanical Metallurgy Laboratory

8 ' ' n σ = ( ) (4) K ε p where n K is the cyclic strain hardening exponent is the cyclic strength coefficient Figure 7: a) Stress-strain loop for constant strain cycling and b) comparison of momotonic and cyclic stress-strain curve for a cyclic hardening materials[1]. Figure 8: Responses of metals to cyclic strain cycles[1]. Mechanical Metallurgy Laboratory

9 1.4 Characteristics of fatigue surfaces Fatigue surfaces normally show no gross plastic deformation and exhibit relatively flat fracture surfaces as shown previously in figure 1 (a). The so called beach mark pattern is often well recognized on the fatigue surfaces on the macroscopic scale. However, if we examine the fatigue fracture surface using a high magnification scanning electron microscope (SEM), we can notice a number of minute striations as depicted in figure 9. These striations are normally observed in the stable fatigue crack growth region. Some metals might not show evident traces of these striations. Figure 9: Fatigue surface examined using a scanning electron microscope, showing the fatigue striations. The striations in the stable fatigue crack propagation are found to be related to the fatigue cycles applied. The occurrence of these striations is due to the plastic blunting process as illustrated in figure 10. If we consider the cross section of the fatigue crack, we will find that the crack is closed at the initial stage or when the minimum stress is applied. During the load increment, the fatigue crack will open according to the amount of the load applied. During crack opening, slips occur in the vicinity of both ends of the crack tips as seen from the arrows. This results in plastic deformation around the fatigue crack tip. When the load reaches the maximum values, plastic blunting process takes place, yielding the maximum crack opening distance as seen at stage 3 from figure 10. After unloading, crack closing takes place and the reversed slips now occur at the crack tips. Finally, the fatigue crack goes back to the initial stage of crack closer but with an increment of one striation as noticed from fatigue crack in stages 1 and 5 respectively. Mechanical Metallurgy Laboratory

10 Figure 10: Plastic blunting model for fatigue striation [4 ]. 1.5 Factors influencing fatigue properties of materials As mentioned previously, characteristics of the applied stresses such as maximum stress, mean stress and stress ratio significantly affects the fatigue behavior of the materials. However, there are a range of factors which are also found to significantly influence the fatigue properties of engineering materials. These are for example, stress concentration, size effect, surface effect, combined stresses, cumulative fatigue and sequence effect, metallurgical variables, corrosion and temperature. Generally, the fatigue crack initiations are observed near the surface. Rough surfaces are therefore undesirable due to stress concentration which accounts for further fatigue crack propagation and eventually lead to global failure. Corrosive environment and high service temperatures are reckoned to have negative effects on fatigue properties of the materials as they accelerate faster rates of both fatigue initiation and propagation. Mechanical Metallurgy Laboratory

11 Figure 11: Fatigue testing machine in the laboratory [4]. Figure 12: Fatigue specimen [4]. Mechanical Metallurgy Laboratory

12 2. Materials and equipment 2.1 Fatigue specimens 2.2 Micrometer or vernier caliper 2.3 Permanent pen 2.4 Fatigue testing machine 3. Experimental Procedure 3.1 Measure dimensions of brass and steel specimens provided and record in tables 1 and 2. If the distance from the load end to the minimum diameter of the specimen is mm, the bending stress, σ, can be calculated the bending stress for a load P (N) is shown in equation P 32 = 3 π D σ (5) 3.2 Conduct the fatigue test at room temperature using the fatigue testing machine as shown in figure 11. Fit one end of the specimen to a motor and fit the other end to a bearing hung with a known weight, indicating the stress applied to the specimen. Start the motor to rotate the specimen at a constant speed. The revolution counter is used to record the number of cycles to which the specimen fails. Record the result in table 1 and Change the weights used and follow the experiment in 2.2. Again, record the results in tables 1 and Construct the S-N curves of the steel specimens. 3.5 Investigate fracture surfaces of broken fatigue specimen and sketch the result in tables 1 and Analyze, discuss the obtained results. Give conclusions. Mechanical Metallurgy Laboratory

13 4. Results Details Specimen 1 Specimen 2 Specimen 3 Specimen 4 Specimen 5 Specimen diameter (mm) Cross-sectional areas (mm 2 ) Weight (kg) Maximum stress (MPa) Frequeny (Hz) No. of cycles to failure (cycles) Fracture surfaces Table 1: Fatigue data of steel specimens. Mechanical Metallurgy Laboratory

14 Figure 13: S-N curve of steel specimens. Mechanical Metallurgy Laboratory

15 5. Discussion Mechanical Metallurgy Laboratory

16 6. Conclusions Mechanical Metallurgy Laboratory

17 7. Questions 7.1 Explain the fatigue endurance limit. What is the obtained fatigue strength in steels? 7.2 Predict the fatigue strength of aluminium. Give reasons. Mechanical Metallurgy Laboratory

18 7.3 Explain the differences between fatigue failure and cleavage fracture. 8. References 8.1 Dieter, G.E., Mechanical metallurgy, 1988, SI metric edition, McGraw-Hill, ISBN Hashemi, S. Foundations of materials science and engineering, 2006, 4 th edition, McGraw- Hill, ISBN ก, ก Engineering materials, 2549, ก ( ), ISBN-10: Roberts, N.P., Hi-Tech instruction manual, HSM19 mk3: Rotating fatigue machine, Mechanical Metallurgy Laboratory

### Tensile Testing. Objectives

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

### 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

### different levels, also called repeated, alternating, or fluctuating stresses.

Fatigue and Dynamic Loading 1 Fti Fatigue fil failure: 2 Static ti conditions : loads are applied gradually, to give sufficient i time for the strain to fully develop. Variable conditions : stresses vary

### 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

### 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

### 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

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).

### 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

### 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

### 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

### Fatigue. 3. Final fracture (rough zone) 1. Fatigue origin. 2. Beach marks (velvety zone)

Fatigue Term fatigue introduced by Poncelet (France) 1839 progressive fracture is more descriptive 1. Minute crack at critical area of high local stress (geometric stress raiser, flaws, preexisting cracks)

### 9. TIME DEPENDENT BEHAVIOUR: CYCLIC FATIGUE

9. TIME DEPENDENT BEHAVIOUR: CYCLIC FATIGUE A machine part or structure will, if improperly designed and subjected to a repeated reversal or removal of an applied load, fail at a stress much lower than

### 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

### 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

Fatigue Failure Due to Variable Loading Daniel Hendrickson Department of Computer Science, Physics, and Engineering University of Michigan Flint Advisor: Olanrewaju Aluko 1. Abstract Fatigue failure in

### 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

### 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

### 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

### 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

### FATIGUE CONSIDERATION IN DESIGN

FATIGUE CONSIDERATION IN DESIGN OBJECTIVES AND SCOPE In this module we will be discussing on design aspects related to fatigue failure, an important mode of failure in engineering components. Fatigue failure

### NOTCHES AND THEIR EFFECTS. Ali Fatemi - University of Toledo All Rights Reserved Chapter 7 Notches and Their Effects 1

NOTCHES AND THEIR EFFECTS Ali Fatemi - University of Toledo All Rights Reserved Chapter 7 Notches and Their Effects 1 CHAPTER OUTLINE Background Stress/Strain Concentrations S-N Approach for Notched Members

### Principles of Fracture Mechanics

8-1 CHAPTER 8 FAILURE PROBLEM SOLUTIONS Principles of Fracture Mechanics 8.1 This problem asks that we compute the magnitude of the maximum stress that exists at the tip of an internal crack. Equation

### 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.).

### 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

### 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,

### Experiment: Fatigue Testing

Experiment: Fatigue Testing Objectives - To demonstrate the use of the Instron servohydraulic testing machine for testing specimens subjected to cyclic (fatigue) loadings. - To analytically approximate

### 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

### SAMPLE FORMAL LABORATORY REPORT. Fatigue Failure through Bending Experiment Adapted from a report submitted by Sarah Thomas

SAMPLE FORMAL LABORATORY REPORT Fatigue Failure through Bending Experiment Adapted from a report submitted by Sarah Thomas Lab Partners: David Henry and James Johnson ME 498 November 10, 2004 Professor

### 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

### 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

### 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

### 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

### 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

### 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

### 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

### Effect of Heat Treatment Process on the Fatigue Behavior of AISI 1060 Steel

International International Journal of ISSI, Journal Vol. of 12 ISSI, (2015), Vol.10 No.1, (2013), pp. 28-32 No.1 Effect of Heat Treatment Process on the Fatigue Behavior of AISI 1060 Steel M. Mehdinia

### 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

### 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

### How Management Decisions Make or Break Plant Uptime

How Management Decisions Make or Break Plant Uptime Abstract How Management Decisions Make of Break Plant Uptime: When you run machines above design rates that decision goes against all that we know about

### FATIGUE TESTS AND STRESS-LIFE (S-N) APPROACH

FATIGUE TESTS AND STRESS-LIFE (S-N) APPROACH FATIGUE TESTING LOADING TEST MACHINES SPECIMENS STANDARDS STRESS-LIFE APPEROACH S-N CURVES MEAN STRESS EFFECTS ON S-N BEHAVIOR FACTORS INFLUENCING S-N BEHAVIOR

### Fatigue of Metals Copper Alloys. Samuli Heikkinen 26.6.2003

Fatigue of Metals Copper Alloys Samuli Heikkinen 26.6.2003 T 70 C Temperature Profile of HDS Structure Stress amplitude 220 MPa Stress Profile of HDS Structure CLIC Number of Cycles f = 100 Hz 24 hours

### MAE 20 Winter 2011 Assignment 6

MAE 0 Winter 011 Assignment 6 8.3 If the specific surface energy for soda-lime glass is 0.30 J/m, using data contained in Table 1.5, compute the critical stress required for the propagation of a surface

### 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

### 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

### Fatigue Performance Evaluation of Forged Steel versus Ductile Cast Iron Crankshaft: A Comparative Study (EXECUTIVE SUMMARY)

Fatigue Performance Evaluation of Forged Steel versus Ductile Cast Iron Crankshaft: A Comparative Study (EXECUTIVE SUMMARY) Ali Fatemi, Jonathan Williams and Farzin Montazersadgh Professor and Graduate

### MIME 3330 Mechanics Laboratory LAB 5: ROTATING BENDING FATIGUE

MIME 3330 Mechanics Laboratory LAB 5: ROTATING BENDING FATIGUE Introduction In this experiment, the finite life fatigue behavior of a smooth cylindrical specimen as shown in Figure 1 will be studied in

### 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),

### 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

### B.TECH. (AEROSPACE ENGINEERING) PROGRAMME (BTAE) Term-End Examination December, 2011 BAS-010 : MACHINE DESIGN

No. of Printed Pages : 7 BAS-01.0 B.TECH. (AEROSPACE ENGINEERING) PROGRAMME (BTAE) CV CA CV C:) O Term-End Examination December, 2011 BAS-010 : MACHINE DESIGN Time : 3 hours Maximum Marks : 70 Note : (1)

### 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.

### Interaction of Hydrogen and Deformation in 316L Stainless Steel

Proceedings of the SEM Annual Conference June 1-4, 2009 Albuquerque New Mexico USA 2009 Society for Experimental Mechanics Inc. Interaction of Hydrogen and Deformation in 316L Stainless Steel Bonnie R.

### Lecture 14. Chapter 8-1

Lecture 14 Fatigue & Creep in Engineering Materials (Chapter 8) Chapter 8-1 Fatigue Fatigue = failure under applied cyclic stress. specimen compression on top bearing bearing motor counter flex coupling

### Numerical Analysis of Independent Wire Strand Core (IWSC) Wire Rope

Numerical Analysis of Independent Wire Strand Core (IWSC) Wire Rope Rakesh Sidharthan 1 Gnanavel B K 2 Assistant professor Mechanical, Department Professor, Mechanical Department, Gojan engineering college,

### DESIGN TO PREVENT FATIGUE

W H I T E P A P E R DESIGN TO PREVENT FATIGUE Overview In 1954, two crashes involving the world s first commercial airliner, the de Havilland Comet, brought the words metal fatigue to newspaper headlines

### Long term performance of polymers

1.0 Introduction Long term performance of polymers Polymer materials exhibit time dependent behavior. The stress and strain induced when a load is applied are a function of time. In the most general form

### 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

### G1RT-CT-2001-05071 D. EXAMPLES F. GUTIÉRREZ-SOLANA S. CICERO J.A. ALVAREZ R. LACALLE W P 6: TRAINING & EDUCATION

D. EXAMPLES 316 WORKED EXAMPLE I Infinite Plate under fatigue Introduction and Objectives Data Analysis 317 INTRODUCTION AND OBJECTIVES One structural component of big dimensions is subjected to variable

### The Truth About Actuator Life: Screw Drive Survival

The Truth About Actuator Life: Screw Drive Survival By Tolomatic, Inc. About the Author: Tolomatic is a leading supplier of linear actuators, both electric and pneumatically driven. Tolomatic's expertise

### Physics 3 Summer 1989 Lab 7 - Elasticity

Physics 3 Summer 1989 Lab 7 - Elasticity Theory All materials deform to some extent when subjected to a stress (a force per unit area). Elastic materials have internal forces which restore the size and

### 1.Adapted from Gordon, J.E., Structures or why things don t fall down, Da Capo Press, Inc., New York, N.Y., 1978, Chapter 15.

Lecture 4: Cyclic loading and fatigue Safe working life: 1 All structures will be broken or destroyed in the end just as all people will die in the end. It is the purpose of medicine and engineering to

### 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

### Completely reversed, strain controlled fatigue tests of a steel alloy with E=210000 MPa resulted in the following data:

Kul-49.4350 Fatigue o Structure Example solutions 5 Problem 5-1. Completely reversed, strain controlled atigue tests o a steel alloy with E=10000 resulted in the ollowing data: a a, (o the stable curve)

### Fatigue crack propagation

1 (20) Repetition Ð Crack initiation and growth Small cracks Shear driven Interact with microstructure Mostly analyzed by continuum mechanics approaches Large cracks Tension driven Fairly insensitive to

### 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

### INFLUENCE OF SHOT PEENING ON CHROMIUM- ELECTROPLATED AISI 4340 STEEL FATIGUE STRENGTH

INFLUENCE OF SHOT PEENING ON CHROMIUM- ELECTROPLATED AISI 4340 STEEL FATIGUE STRENGTH *Voorwald, H. J. C., Silva, M. P., Costa, M. Y. P., a Pigatin, L. W., Marques, B. M. F. Fatigue and Aeronautic Research

### 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

### 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

### ME311 Machine Design

ME Machine Design Lecture 5: Fully-Reversing Fatigue and the S-N Diagram W Dornfeld Oct26 Fairfield University School of Engineering Discovering Fatigue With the Industrial Revolution came the steam engine

### POWER SCREWS (ACME THREAD) DESIGN

POWER SCREWS (ACME THREAD) DESIGN There are at least three types of power screw threads: the square thread, the Acme thread, and the buttress thread. Of these, the square and buttress threads are the most

### ANALYSIS OF THE FATIGUE STRENGTH UNDER TWO LOAD LEVELS OF A STAINLESS STEEL BASED ON ENERGY DISSIPATION

EPJ Web of Conferences 6, 6 38009 (00) DOI:0.05/epjconf/000638009 Owned by the authors, published by EDP Sciences, 00 ANALYSIS OF THE FATIGUE STRENGTH UNDER TWO LOAD LEVELS OF A STAINLESS STEEL BASED ON

### 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

### 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.

### (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

### Rolling - Introductory concepts

Rolling - Introductory concepts R. Chandramouli Associate Dean-Research SASTRA University, Thanjavur-613 401 Joint Initiative of IITs and IISc Funded by MHRD Page 1 of 8 Table of Contents 1. Rolling -

### 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

### 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,

### Analysis of Fatigue Fracture Surfaces in Aluminum Alloy 2024 T351

International Journal of Mining, Metallurgy & Mechanical Engineering (IJMMME) Volume, Issue (03) ISSN 30 400 (Online) Analysis of Fatigue Fracture Surfaces in Aluminum Alloy 04 T35 Benguediab Mohamed,

### Volume 54 2009 Issue 2 MLCF AN OPTIMISED PROGRAM OF LOW-CYCLE FATIGUE TEST TO DETERMINE MECHANICAL PROPERTIES OF CAST MATERIALS

A R C H I V E S O F M E T A L L U R G Y A N D M A T E R I A L S Volume 54 2009 Issue 2 M. MAJ,J.PIEKŁO MLCF AN OPTIMISED PROGRAM OF LOW-CYCLE FATIGUE TEST TO DETERMINE MECHANICAL PROPERTIES OF CAST MATERIALS

### Lecture 18 Strain Hardening And Recrystallization

-138- Lecture 18 Strain Hardening And Recrystallization Strain Hardening We have previously seen that the flow stress (the stress necessary to produce a certain plastic strain rate) increases with increasing

### 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

### RESILIENT MODULUS: WHAT, WHY, AND HOW?

RESILIENT MODULUS: WHAT, WHY, AND HOW? Shane Buchanan, Vulcan Materials Company, 08/1/07 Resilient modulus (M r ) continues to be a key design parameter for pavement systems. Accurate knowledge of the

### Development of U-shaped Steel Damper for Seismic Isolation System

UDC 624. 042. 7 Development of U-shaped Steel Damper for Seismic Isolation System Kazuaki SUZUKI* 1 Atsushi WATANABE* 1 Eiichiro SAEKI* 1 Abstract Seismic isolation system was widely admitted after Hanshin-Awaji

### Examination of failed landing gear struts MD Helicopters, Model MD520N VH-MPI 21 June 2004

Appendix A: Technical Analysis Report Examination of failed landing gear struts MD Helicopters, Model MD520N VH-MPI 21 June 2004 Report No. 35/04 Task No. BE/200400015 Occurrence No. BO/200402243 Page

### Citation Journal of Constructional Steel Research, 2014, v. 96, p

Title The Art of Coupon Tests Author(s) Huang, Y; Young, B Citation Journal of Constructional Steel Research, 014, v. 96, p. 159-175 Issued Date 014 URL http://hdl.handle.net/107/00516 Rights NOTICE: this

### Fatigue Life Estimates Using Goodman Diagrams

Fatigue Life Estimates Using Goodman Diagrams by Robert Stone The purpose of this paper is to review the proper methods by which spring manufacturers should estimate the fatigue life of a helical compression

### Yield Criteria for Ductile Materials and Fracture Mechanics of Brittle Materials. τ xy 2σ y. σ x 3. τ yz 2σ z 3. ) 2 + ( σ 3. σ 3

Yield Criteria for Ductile Materials and Fracture Mechanics of Brittle Materials Brittle materials are materials that display Hookean behavior (linear relationship between stress and strain) and which

### 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

### 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

### EFFECT OF SEVERE PLASTIC DEFORMATION ON STRUCTURE AND PROPERTIES OF AUSTENITIC AISI 316 GRADE STEEL

EFFECT OF SEVERE PLASTIC DEFORMATION ON STRUCTURE AND PROPERTIES OF AUSTENITIC AISI 316 GRADE STEEL Ladislav KANDER a, Miroslav GREGER b a MATERIÁLOVÝ A METALURGICKÝ VÝZKUM, s.r.o., Ostrava, Czech Republic,

### Ultrasonic Technique and Device for Residual Stress Measurement

Ultrasonic Technique and Device for Residual Stress Measurement Y. Kudryavtsev, J. Kleiman Integrity Testing Laboratory Inc. 80 Esna Park Drive, Units 7-9, Markham, Ontario, L3R 2R7 Canada ykudryavtsev@itlinc.com

### 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

### 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:

### Description of mechanical properties

ArcelorMittal Europe Flat Products Description of mechanical properties Introduction Mechanical properties are governed by the basic concepts of elasticity, plasticity and toughness. Elasticity is the

20 FATIGUE LIFE OF BOLT SUBJECTED TO FATIGUE LOADING CONDITIONS ABSTRACT K. Din and M. T. H. Ghazali Faculty of Civil Engineering, Universiti Teknologi MARA, Shah Alam, Malaysia E-mail: kdfila@hotmail.com

### Effect of Temperature and Aging Time on 2024 Aluminum Behavior

Proceedings of the XIth International Congress and Exposition June 2-5, 2008 Orlando, Florida USA 2008 Society for Experimental Mechanics Inc. Effect of Temperature and Aging Time on 2024 Aluminum Behavior

### 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

### 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