Figure (3.12) shows two flexible trusses A and B. Truss A is moving towards truss B which is fixed. The horizontal and vertical displacement are prescribed for nodes 1 and 3 in truss A. The dynamic and static coefficients of friction are assumed to be 0.5 between the two trusses. Analytical solution for the problem can be readily found. The results precisely agrees with the analytical solution. Figures (3.13) and (3.14) show the displacements of nodes 1, 2 and 6. Figure (3.15) shows the contact forces at node 2.