Elastic-plastic dynamic buckling of a high pier under impulse loads

Considering the influence of transverse shear deformation and large displacement, the basic non-linear dynamic equations of a high pier under impulse loads were established with a bi-linear constitutive model. By supposing displacement shape functions and applying Galerkin method, the dynamic governing equations with respect to time were gained. They were solved numerically. The critical loads and displacement response curves were obtained, and the influences of various loads and geometry parameters of the high pier on the critical loads were analyzed. The loads-displacement curves under triangle impulse loads were compared with those under rectangle impulse ones. The displacement response curves under rectangle impulse loads with different peaks and the critical loads-flexibility of the pier curves under rectangle impulse loads were given. The influence of different acting time intervals of rectangle impulse loads on the critical loads was analyzed. The influence of the plastic deformation on the stability of the high pier was analyzed. The process within that the plastic zone appeared and enlarged was provided.