Nondestructive evaluation of pyroshock propagation using hydrocodes

Abstract

Pyroshock or pyrotechnic shock generated by explosive events of pyrotechnic devices can induce fatal failures in electronic payloads. Therefore, understanding of pyroshock propagation through complex structures is necessary. However, an experimental approach using real pyrotechnic devices is quite burdensome because pyrotechnic devices can damage test structures and new test structures are necessary for each experiment. Besides, pyrotechnic experiments are quite expensive, time-consuming, and dangerous. Consequently, a nondestructive evaluation (NDE) of pyroshock propagation without using real pyrotechnic devices is demanded. In this study, a nondestructive evaluation technique for pyroshock propagation estimation using hydrocodes is proposed. First, pyroshock propagation is numerically analyzed using AUTODYN, a commercial hydrocodes. Hydrocodes can handle stress wave propagation including elastic, plastic, and shock wave in the time domain. Test structures are modeled and pyroshock time history is applied to the place where the pyroshock propagation originates. Numerical NDE results of pyroshock propagation on test structures are analyzed in terms of acceleration time histories and acceleration shock response spectra (SRS) results. To verify the proposed numerical methodology, impact tests using airsoft gun are performed. The numerical analysis results for the impact tests are compared with experimental results and they show good agreements. The proposed numerical techniques enable us to nondestructively characterize pyroshock propagation.