Reflected Wave Eliminator for Blast Wave Simulator

Blast Wave Simulator (BWS) is a form of shock tubes used to generate shock waves with a typical Friedlander profile. In a BWS, the samples are tested in reflective and diffractive modes. In reflective mode, wave reflections from the shock tube’s closed-end cause secondary loading in the specimen, which limits the suitability of BWS for testing the long-term dynamic response of the specimens since the secondary loading will affect the actual response. This study attempts to develop a reflected wave eliminator (RWE) fixture for an existing BWS facility to attenuate the peak positive overpressure of the reflected waves. The RWE used in this study is a self-opening flap that remains stationary during primary wave traversal, and it opens completely before the arrival of reflected waves in a closed-end shock tube. This study investigated the efficiency of the RWE for different shock strengths. The RWE reduced the peak overpressure up to 55.37% and 13.06% for strong and weak shock cases defined in this study. So, the efficiency of the RWE for a particular shock strength depends upon the mass of the flap. Our future study will focus on developing an adjustable mass flap to achieve the optimal flap opening rate for different strengths. With a properly designed RWE, the effects of secondary loading on the specimen in a closed-end shock tube can be significantly reduced.