Item no.: F13

Introduction

The Young Modulus, named after Thomas Young (1773 to 1829) who was an outstanding British polymath in material fields, is usually used to define the proportionality of normal stress and normal strain for metal material subjected to external force. Such proportionality constant only prevails within the working region below elastic limit i.e., transient distortion or deflection of material might be recovered after the external force is removed. It is, of course, far lower than ultimate limit accessed where the permanent strain or failure of material will occur. Thus using the Young Modulus to predict the validity of substance, especially in elastic behavior, seems to be inevitable prior to it being in engineering application. Also it could be treated as an effective manner for engineer to evaluate the safety factor of substance selected for public construction.

Objectives

1. Determine the Young’ Module by metal wire.
2. Determine the Young’ Module by deflection of a beam.
3. Determine the length and thickness by caliper gauge and micrometer

Experiment— Determine the Young’ Module by metal wire

To estimate the Young’s Module of material, tension method and beam- deflection method are usually introduced using the instrument of load cell, vernier calipers and scalar meter. Firstly in tension method, the measurement of wire -enlargement ration ΔL/L, caused by force F subjected to metal wire of one end fixed, might carried out, here radial displacement is assumed to be far smaller than the axial extension, i.e., only the shear stress and strain along the force component, in this subject, will be taken into account.