# The Science and Engineering of Materials

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• Published : April 27, 2013

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Tensile Test

ABSTRACT

The tensile test experiment being done purposely to determine the deformation of our specimen which is low carbon steel or also called as mild steel, and it also to identify the fracture characteristic of the specimen based on the result that we got through the experiment. Based on the data presence from this experiment ,we used it to calculate the stress and strain using a theoretical formula. Through all the calculation that we got, we construct a table and make a graph to clearly observed the relationship between stress and strain. Then, by using that graph, we identify where are the modulus of elasticity, what is the ultimate stress for this specimen and how the type of fracture for this specimen. All of this issue, we had been discussed more details in our discussion. In this experiment we used a tensile testing machine to elongate the specimen but we drive it manually, we also use a vernier caliper to measure a length of elongation of the specimen and this experiment we carrying according to procedure given. Finally, at the conclusion we were strictly restated our stand about the result of this experiment which were value of modulus elasticity, ultimate stress and our cross-sectional of fracture specimen. The knowledge that we got from this experiment were very useful for our real job application.

CONTENTS PAGES

Objective 1

Introduction 1

Theory 2

Apparatus 3

Procedure 4

Results 5 - 10

Discussion 11 - 18

Conclusion 19

References 20

Raw Data 21 -23

OBJECTIVES

To study the deformation and fracture characteristics of samples under tension. Using an Instron testing machine model 4206 you will obtain a force-displacement curve. From the curves and vernier caliper measurements of samples, the modulus of elasticity (Young's Modulus) can be determine and also

The : a- Yield stress
b- Ultimate tensile stress
c- Elastic or Young's modulus, (ε) of a material can all be determined from the stress- strain curve for that materials.

INTRODUCTION

Tensile test is known as a basic and universal engineering test to achieve material parameters such as ultimate strength, yield strength, % elongation, % area of reduction and Young's modulus. These important parameters obtained from the standard tensile testing are useful for the selection of engineering materials for any applications required.

The tensile testing is carried out by applying longitudinal or axial load at a specific extension rate to a standard tensile specimen with known dimensions (gauge length and cross sectional area perpendicular to the load direction) until it failure. The applied tensile load and extension are recorded during the test for the calculation of stress and strain.

A standard specimen is prepared in a round or a square section along the gauge length. There are many equipment or machine that can be used for tensile test. For this experiment, we use Instron testing machine model 4206 and mild steel as specimen.

THEORY

The curve is a typical metallic behavior :

The engineering stress is plotted (force divided by the original cross-sectional area). At small strain values (the elastic region). The relationship between stress and strain is nearly near. Within this, the slope of the stress and strain is nearly linear. Within this region, the slope of the stress-strain curve is defined as the elastic modulus. Since many metals lack a sharp yields points, i.e a sudden, observable transition between the elastic region and the plastic region, the yields points is often defined as the stress that gives rise to a 0.2% permanent plastic strain. By this...