Material damping under random excitation

Abstract

The damping capacity of three materials subjected to narrow-band strain fluctuations is investigated, the material effectively undergoing sinusoidal strain with randomly varying amplitude. For this case, a theoretical relationship is established between the expected value of the energy dissipated per unit volume of the material per period of the narrow-band process and the r.m.s. value of the strain history. This is expressed in terms of material damping constants obtained from harmonic damping measurements. The theoretical relationship is checked against experimental results from narrow-band random experiments on three different materials over low and intermediate stress ranges. Good agreement is found.