ShockSat Shock Propagation Prediction Using Transient Hybrid Finite Element/Statistical Energy Analysis

Pyrotechnic devices are commonly used in launch vehicles and space vehicles to separate hardware at events throughout a launch. These pyrotechnic devices are reliable, but they transmit stress waves throughout the separated structures. Mission success relies on accurate knowledge of the vehicles shock environments required to ensure sensitive components can survive the shock event. Shock analysis has traditionally relied on empirically based factors that attenuate the shock levels as the number of structural joints and distance between the shock source and component increase. These empirical approaches do not account for propagation through complex structures with multiple load paths, joints, and localized damping, nor do they account for structural resonances which can increase the response. This paper demonstrates the capability of using a hybrid Finite Element Analysis (FEA)/Statistical Energy Analysis (SEA) approach for much improved shock predictions. The approach is demonstrated on NASA’s open source shock test data set named ShockSat, which includes data from simplified tap tests and pyrotechnic frangible joint firings. The hybrid FEA/SEA approach is computationally efficient to capture shock up to 10 kHz for modally dense systems. Furthermore, the approach enables a unique excitation method to represent pyrotechnic shock events for which the forcing function is not known.