Planar stress wave attenuation in plates with circular voids and inclusions

This paper addresses planar stress wave attenuation in finite rectangular aluminum plates with circular voids and two types of inclusions; namely, high-density polyethylene (HDPE) and steel. The voids and inclusions act as a source of impedance mismatch and scatter the waves within the plates. The plates studied here have multiple numbers of circular voids and inclusions with different dimensions and positions, and are subjected to short duration transient loadings. To find the most efficient layout and dimensions of the circular voids and inclusions within these plates, a heuristic optimization methodology is developed based on Genetic Algorithms (GA). This methodology is coupled with the Finite Element (FE) method to analyze the wave propagation behavior of the plates under elastic response. The developed optimization methodology is capable of updating the FE model of each candidate design during the optimization procedure, as each in general has different geometric characteristics. The results show that the attenuation capacity of the plates with circular voids and inclusions is a complex function of the dimensions of the plates and the wavelength associated with the transient loading, as well as, the type, positions and dimensions of the voids and inclusions. It is observed that significant amounts of planar stress wave attenuation can be achieved, if the dimensions and positions of the circular voids and inclusions are selected appropriately.