ABSTRACT
High speed and high acceleration shock waves may cause damage to structures such as undesirable motions, misalignments, joint failure and possibly a destruction of structures. Published research considers attenuation of vibrations using different types through the active, passive and semi-active damping methods. One way of passively mitigating the vibration is the use of differences in material properties. Promising results were reported in the reduction of high acceleration vibration using differences in material stiffness and geometry (Solaroli et al. 2003 and Toso & Baz 2004). Under such conditions, attenuation of shock wave vibrations may be explained based on the wave reflection and transmission at a boundary. The speed of a shock wave depends on the properties of the medium in which it travels, however if a material or structural junction exists within a structure, it results in a wave speed mismatch and impedance discontinuity. The difference in impedance at the junction between two materials results from a mismatch in their wave speed or a sudden change in the junction geometry or both. Part of the shock wave is transmitted and the others reflected backward at the junction. The backward reflection of a part of the wave helps to reduce the intensity and magnitude of the peaks of the waves in a structure. Based on this concept, the mitigation of high acceleration shock waves in structures may be attained.
