Development of New Infinite Element for Numerical Simulation of Wave Propagation in Soil Media

In numerical simulation of soil media, the problem of wave propagation is of a great importance. Proposed in this paper is a new formulation of infinite elements which can be used in numerical simulation of wave propagation problems in infinite domains. In numerical simulation of wave propagation, the finite elements are used to model the near field, whereas the infinite elements are used to represent the behaviour of the far field. Formulations and various implementation aspects of the proposed infinite elements are illustrated. The accuracy and efficiency of the proposed approach is considered by comparing the obtained results with analytical and other numerical results. For better explanation, a couple of examples were analyzed such as one dimensional wave propagation problems arising from the Heaviside step function and impulse functions. In order to get a more complete insight, two dimensional wave propagations in soil medium were considered and the results are presented accordingly. Finally, a soil layer subjected to seismic excitation was analysed. The new infinite element was developed using the User Programmable Features of the ANSYS software, which enables creating new elements within the robust ANSYS core algorithm. The main advantage of the proposed infinite elements is that they can be used directly within a finite framework with minor modifications such as the Jacobian matrix and added absorbing properties. The performed analysis using the infinite elements shows very promising results and provides a good tool for simulation of boundary conditions.