ABSTRACT
Strain energy is defined as the energy stored within an elastic body when the solid matter is deformed by an applied loading. Thus, strain energy is equivalent to the work done by the external forces acting on a body. The general expression defining the strain energy is
∫= σ ε + σ ε + σ ε + τ γ + τ γ + τ γ12 ( )U dVxx xx yy yy zz zz xy xyV yz yz xz xz (9-1) For a bar of length L under only axial loading F, Expression (9-1) reduces to
∫= σ ε12 ( )U dVxx xxV (9-2) where the volume change is dV = Adx, the area times the change in length.
