A spectral analysis approach to wave propagation in layered solids

The impact resistance of a structure depends in part on its ability to propagate energy away from the impact site. Further, many situations arise when a detailed analysis of the local behavior is necessary. This is especially true in layered media because the interaction of stress waves with various interface boundaries can generate highly localized wave behavior. This thesis develops a novel spectrally formulated element designed expressly for solving these types of problems in a highly efficient manner. The spectral formulation is first applied to the problem of a line load on the half plane with particular attention paid to the generation of Rayleigh surface waves. It is then used to study the effect of free, fixed, and elastic boundaries on incident waves. Finally, the case of waves in multi-layered solids is treated. These analytical studies are complemented at each stage by experimental studies using strain gage and accelerometer histories, plus an ultra-high speed camera for dynamic photoelasticity. The availability of this data affords the opportunity to use it actively as input to the spectral tools to solve inverse problems. This synergy of experiment and spectral analysis forms a very powerful tool