Deformation

Synonyms

Strain

Definition

Deformation. Change in size, shape, and/or volume of an object under the effect of internal or external forces.

Introduction

In continuum mechanics, as well as in engineering applications, deformation is often referred to as the strain induced when external forces are applied to a body (e.g., compression, tension, shearing, bending , and/or torsion). However, deformation can be also induced by intrinsic body forces (e.g., gravity), as well as by changes in the temperature or by chemical reactions (Jones 2009). A straightforward example of deformation is shown in Fig. 1, where a force is axially applied to a rod. The strain (ε) occurring along the rod axis can be calculated as the change in length ΔL with respect to the initial length:

$$ \varepsilon =\frac{\varDelta L}{L_1}=\frac{L_2-{L}_1}{L_1} $$

(1)

Fig. 1

1-D deformation of a rod subjected to axial stress