Pyrotechnic devices are commonly used to achieve various purposes such as separation of boosters, satellites, fairing, and stages. The aerospace structure is exposed to a shock environment induced by separation mechanism of pyro devices. pyrotechnic devices produce pyroshock which is a high structural shock wave that can easily cause failures in electronic and optical components. Various numerical and experimental pyroshock simulation techniques have been studied to predict explosive-induced pyroshock effect that may lead to improper qualification of hardware.
In this study, the multi-point simultaneous laser pyroshock measurement system based on Laser Doppler Vibrometer (LDV) is developed. LDV is a non-contact sensor that measures the Doppler shift of a laser beam reflected from a target on the vibrating surface. To verify the developed system performance, pyroshock measurement tests are performed using two different sensor such as PCB and LDV. The pyroshock are measured at three points and compared with the measurement results in terms of peak-to-peak acceleration and Shock Response Spectra (SRS). Comparison results show good similarity in both the time and frequency domains. In addition, developed pyroshock measurement system was utilized for comparison experiment of pyrotechnic devices such as explosive bolt and pyro-lock which was designed and manufactured by Agency for Defense Development (ADD) and Hanwha Corporation.
Next, this thesis deals with pyroshock propagation prediction on the structures. Pyroshock propagation visualization system that uses only laser excitation and training algorithm is developed. Pyroshocks are reconstructed by breaking down a laser shock signal to frequency band which is used in SRS calculation, amplifying the difference of the maximum acceleration between pyroshock and laser-induced shock at each band, and super-positioning all the amplified signals at each band. Finally, reconstructed pyroshock at interesting area is used to propagation visualization process. For system validation, developed system was applied on carbon fiber reinforced plastic (CFRP) honeycomb plate with linear explosive for simulation and visualization of pyroshock propagation. Developed pyroshock propagation visualization system is superior in term of suitability for real structures pyroshock simulation.