International Journal of Engineering and Technology

Impact problems have recently been the subject of intense research. Impact tests have found a great interest by several researchers, and dynamic testing apparatus were developed in different laboratories. In addition, several theoretical models were developed to simulate impact tests theoretically and get the corresponding stress-strain relations. A general mixed finite element formulation (u – w – p) is presented in this paper. This formulation includes the inertia effects and the materials (solid grains and water) are considered compressible. The application of this formulation in solving impact problems of dry sand is made by restricting the boundary conditions concerning the pore fluid, and comparisons are made between laboratory tests conducted at the University of Baghdad in 1989 against elasto-plastic model named ALTERNAT are made herein. A comparison is made between the experimental results and theoretical ones which are obtained by simulating the impact tests using the finite element method. The ALTERNAT model gave very good predictions for displacements of dense (Dr = 75 %) sands when subjected to double impacts.