What is rate of strain?

The rate of strain is a measure of how much a material deforms or changes shape per unit time. It is the derivative of the deformation with respect to time and is measured in units of per second (s^-1). The rate of strain is a key parameter in the study of fluid mechanics, where it is used to characterize the flow of fluids and the behavior of shear stresses. It is also an important factor in the study of materials science and mechanics, where it is used to investigate the deformation and failure of solids under stress. The rate of strain is typically denoted by the symbol γ (gamma) and is calculated as the change in strain (ε) divided by the change in time (t): γ = dε/dt.