Large plastic deformation of steel plates at impulsive blast load.

Large plastic deformation of homogeneous square and rectangular steel plates at high impulsive blast loading has been investigated. The plates were clamped along all edges to a rigid support. The typical pyramidal shape of the test objects proves that the movement is completely different from static laoding effects. High peaks of shear force cause tearing off the plates along the support at impulsive overloading. The targets can withstand high impulsive loading only if they are designed in such a manner that tearing off is prevented and large deflection is possible. Small-scale experiments at plates of 1 qm, 1/4 qm and 1/16 qm were conducted to find the deformation of homogeneous steel plates as a function of blast impulse. The distribution of blast impulse at the plate's surface was carefully measured. The test results from differently sized plates are in agreement with Hopkinson-Cranz scaling. The observed pyramidal shape of the test objects and the maximum deflection at the plate's center are in agreement with Finite Element structural dynamic calculations. Acceleration, velocity and displacement at any point of the plate as a function of time can be calculated by the code.