Numerical Study of Separation Characteristics of Piston-Type Explosive Bolt

An explosive bolt is a simple, highly reliable, and efficient pyrotechnic release device widely used in spacecraft and rocket launchers. High shock transient response is generated during the separation of a release device, which tends to damage the nearby micromechanism and hardware. The purpose of this article is to predict the shock response of an explosive bolt. In this paper, the separation process of a piston-type explosive bolt is simulated by using a hydrocode named AUTODYN and the influence of the charge amount on separation time, separation speed, and separation shock is analyzed. Results show that piston-type explosive bolts obey a tensile fracture mechanism and that the critical charge amount for separation is 354-398 mg of PETN. The separation shock of such an explosive bolt mainly includes two aspects: the shock caused by explosive detonations and the impact of the piston at the end of the stroke. As the charge amount increases, the separation time decreases, the speed of the piston and screw increases first and then decreases, and the separation shock first increases and then stabilizes. On a simple aluminum plate, the shock response decreases as the distance from the shock source increases, obeying the power function attenuation law.