ACOUSTIC FATIGUE AND DAMPING TECHNOLOGY IN FRP COMPOSITES

There is considerable interest in the use of composite materials in ae rospace structures, One important area is to develop a stiff, lightwei ght composite material with a highly damped, high-temperature polymer matrix material. This paper concerns the application of such material, in the form used in thin skin panels of aircraft, and investigates of its fatigue properties at both room and high temperature. Flexural fa tigue tests have been carried out at two different temperatures and ha rmonic three-dimensional finite-element (FE) analyses were performed i n order to understand the dynamic behaviour of plates, Random acoustic excitation tests using a progressive wave tube, up to an overall soun d pressure level of 162 dB, at room temperature and high temperatures were also performed in order to investigate the dynamic behaviour of p anels made of the materials. Parameter studies were carried out in ord er to examine various methods for including damping in the structure, and conclusions have been drawn concerning optimal incorporation of a highly damped matrix material into a high-performance structure. (C) 1 997 Elsevier Science Ltd.