Characterization of Multilayered Stress Wave Attenuators Subjected to Impulsive Transient Loadings

This paper describes the wave-propagation behavior of multilayered structures and proposes an optimization procedure for designing layered stress wave attenuators. Two types of stress wave attenuators were investigated, straight and nonstraight configurations, and their wave behaviors were analyzed using the concept of longitudinal waves in rods and flexural waves in Timoshenko beam formulations. The underlying concept in this research relies on the reflection and transmission of waves at different types of discontinuities, such as boundaries, impedance mismatches, and angled joints. Therefore, the effects of these discontinuities were explored thoroughly, and their attenuation capacity was investigated using explicit formulas. These concepts then were used to develop a heuristic optimization procedure to obtain efficient layered stress wave attenuators by properly tuning the length and material of each layer. It was assumed that the stress wave attenuators were subjected to impulsive transient loadings with similar duration as that of blast waves. The results obtained demonstrate that it is very difficult to attenuate the amplitude of transient loadings with the duration of blast waves in structures using straight layered configurations having small thickness, whereas symmetric nonstraight architectures can be rather effective for achieving the desired attenuation of impulsive loadings. (C) 2014 American Society of Civil Engineers.