Strain Rate

Tensile or compression testing of samples is frequently performed at a constant strain rate, i.e. the material is deformed so that its engineering strain changes linearly with time.

Strain Rate = de /dt ; e = dL / L₀ , where L₀ is the initial sample length.

In a test situation the strain rate should be chosen to provide sufficient data points in the duration of the measurement to give a good load deformation curve.

It should be noted that material response is strain rate dependent and if very high or very low strain rates are used different material parameters may be obtained.