Axial Loading

MEC411

Faculty of Mechanical Engineering Engineering Mechanics Centre of Studies

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Axial Loading

Materials for this chapter are taken from :
1. 2. Ferdinand P. Beer, E. Russell Johnston,Jr, John T. Dewolf, David F. Mazurek “ Mechanics of Materials” 5th Edition in SI units R.C.Hibbeler “ Mechanics of Materials “ Seventh Edition
Ch 2 - 1

MEC411

Faculty of Mechanical Engineering Engineering Mechanics Centre of Studies

Introduction
Suitability of a structure or machine may depend on the deformations in the structure as well as the stresses induced under loading. Statics analyses alone are not sufficient. Considering structures as deformable allows determination of member forces and reactions which are statically indeterminate. Determination of the stress distribution within a member also requires consideration of deformations in the member. Chapter 2 is concerned with deformation of a structural member under axial loading. Later chapters will deal with torsional and pure bending loads.

Ch 2 - 2

MEC411

Faculty of Mechanical Engineering Engineering Mechanics Centre of Studies

Saint-Venant’s Principle
Saint-Venant’s Principle

states that both

localized deformation and stress tend to “even out” at a distance sufficiently removed from these regions.

Ch 2 - 3

MEC411

Faculty of Mechanical Engineering Engineering Mechanics Centre of Studies

Normal Strain under Axial Loading

P σ = = stress A

ε=

δ
L

2P P σ = = 2A A

= normal strain

ε =

δ

L

P σ= A 2δ δ = ε= 2L L
Ch 2 - 4

MEC411

Faculty of Mechanical Engineering Engineering Mechanics Centre of Studies

Stress-Strain Test

rutlandplastics.co.uk

www.tensilkut.com

deeshaimpex.com

Tensile Test Machines & Specimens
Ch 2 - 5

MEC411

Faculty of Mechanical Engineering Engineering Mechanics Centre of Studies

Stress-Strain Test: Ductile Materials

necking rupture

Test specimen with tensile load elongation occurs