A study is made of the elastic-plastic responses of portal and free square frames subjected to concentrated explosive impulses. A finite-difference method, which reduces the structure to small masses connected by light links, is used to solve the equations of motion of the deforming frames. The links are assumed to have the same strength properties as the material of the structure. Dynamic strain is measured experimentally, instantaneous profiles are obtained from high-speed photographs and the final deflections substantiate the predictions of the analytical method.
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