The problem discussed in the paper summarizes extensive studies of imperfections in contact problems as occurring in FE silo simulations. The main problem representing all kinds of imperfections is the so called switch phenomenon, which is a stress peak during the dynamic discharge of the silo. Caused by the fact, that the results gained in the past can be traced back to a numerical corner singularity, the results of several methods to improve this problem are compared, showing, that a approach presented here comes to grips to the singularity problem.
