Silent Boundary Scheme and Analysis of Existing Methods of providing Silent Boundary

Abstract

For dynamic analysis, it is required to provide viscous boundaries in PLAXIS to reduce the boundary effects and to prevent the reflection of waves from boundaries. So, a study has been carried out to compare the various methods of providing silent boundaries and to see the effectiveness of viscous boundaries used in PLAXIS. In this work, three methods of providing silent boundaries, which are viscous boundaries, local damping, and extended boundary, are analyzed using a 2D finite element program in FORTRAN by considering the simple problem of a two-dimensional vertical bar. Parameters, such as, normal stress at the bottom, vertical displacement at the top, potential energy, kinetic energy, strain energy, and total energy of bar are determined with and without using the above three methods of providing silent boundaries. Results are compared using graphs. It was observed that standard viscous boundaries are not much effective for static analysis but most effective for dynamic analysis.