EFFECT OF CREEP ON THE VIBRATIONS OF MECHANICAL SYSTEMS SUBJECTED TO RANDOM EXCITATION

Abstract

Although mechanical systems subjected to random excitations have been extensively studied during the past few years, there appears to be no analysis which takes into account the possible creep deformation of the mechanical elements due to the loading on the system. As is well known the creep of metals, being an energy absorbing process introduces an equivalent damping into the system and hence attenuates the vibrations. A study of this creep damping in coiled springs bas been made by Hoff.

In this paper the study of mechanical systems idealised by a single degree of freedom system, which admits both elastic anti creep deformations has been undertaken. By assuming a stationary, Gaussian white noise type of Random excitation on the system. the statistical properties of the response have been obtained with the aid of Generalised Harmonic analysis. Also, an estimate of the damping introduced into the system due to creep, has been made by evaluating the energy absorbed by the creep process.