In the present meshfree boundary-domain integral equation method, where the matrices are non-symmetric, convergence
cannot be guaranteed, but the inequalities shown in Eq. (26) should equally be observed in order not to introduce and additional source of instability. Thus seven kinds of combinations of the parameters with a fixed time step of Δt¼0.005 are investigated in details to obtain the proper ones. In the damped Newmark's algorithm, three δ values are chosen,
namely, δ¼0.5, 0.6 and 0.7, respectively. For each δ combining with three α values, 0.5, 0.7 and 0.9 are using to compose seven parameter groups. By using these selected parameters, the displacements u2 of point A computed through the damped Newmark's algorithm are described in Fig. 5. It can be seen that, all the results are stable, and the parameter δ plays a vita effect. Because