Abstract
Pyrotechnic is used for the separation system of the rocket payload fairing. This system was utilized the fracture of the notched bolt of the titanium alloy using the pyrotechnic. However, the separation impact force using pyrotechnic is expected to decrease for enhancement of international competitiveness of rocket launch vehicle. In order to develop analytical methodology for impact fracture behavior of notched bolt and understand separation mechanism, the explicit calculations based on finite element methods were performed for test using Split-Hopkinson pressure bar method in the present study. The Johnson-Cook model, which represents visco-plasticity and high-temperature softening characteristics, was applied for titanium alloy. The computed result was good agreement with to the test result. In addition, it was confirmed that the impact force can be determined tension force until fracture on the notch surface. This methodology has possibility of effective tool for estimation of fairing separation force and development of lower impact system.
