Shock Environment Characterization : Experimental and Numerical Methods

Reliable experimental characterization of high-g shock environments is a long-standing problem which faces much difficulty. The shock levels experienced by various defense-related structural and mechanical components are not always easily obtained in the true environments but are known to span a significant range of peak accelerations and pulse durations. The reproduction of these high-g shock levels in a controlled setting is highly important but also quite complicated. A system which is characterized by substantial energy output, a high level of precision, and adjustability is ideal for producing the varying and intense conditions experienced by components subjected to shock loads. The UCSD Blast Simulator, a complex experimental device which simulates explosive blasts without a fireball or the use of explosive materials, has proven to be an appropriate tool for this application. The system uses high-precision, computer-controlled hydraulic actuators to fire a piston mounted with various impact materials at high velocities into the specified test article. In the developed experimental series, a cylindrical steel specimen is launched by the Blast Simulator from a set of custom pedestals into a catcher pit. The response of the test article to the impact is acquired and analyzed with various methods. The experimental shock environment characterization and analysis is supplemented by a set of numerical models developed with an advanced finite element tool. The simulations examine the loading arrangements of several tests and the resulting specimen response. With the calibrated models, extrapolation to other possible experimental configurations and the prediction of corresponding shock levels is produce