Characterization of discretely graded materials using acoustic wave propagation

Functionally graded materials (FGMs) have great potential as energy absorbing devices, electrical transducers, thermal barriers, etc. Study of the propagation of elastic waves is imperative for a number of such applications. In this paper, a simple one-dimensional model is proposed to study the stress waves in discretely graded media. The model uses spectral approach to determine the stresses due to the incident and reflected waves in FGMs. It has been observed that FGMs attenuate and delay the peak stresses considerably as compared to composites with sharp interfaces. Performance of different number of inner layers on the reflected wave characteristics has been discussed. Stress time history profiles are also presented for Alumina–Aluminum FGMs that are used in armor applications.