ACA-accelerated Time Domain BEM for Dynamic Analysis of HTR-PM Nuclear Island Foundation

摘要

This paper presents the use of a three-dimensional time domain boundary element method (BEM) in conjunction with adaptive cross approximation method (ACA) for dynamic analyses of the HTR-PM nuclear island foundation. The advantage of this approach is that only foundation of the HTR-PM nuclear island and limited surfaces of the supporting half-space soil medium are modeled and analyzed in a direct time stepping scheme. In addition, the ACA can compress the BEM coefficient matrices at each time step efficiently, therefore allowing larger models to be analyzed compared with conventional BEMs. In order to discretize the boundary integral equation (BIE) we use collocation method and eight-node discontinuous quadratic element. In order to preserve the causality condition an element subdivision technique suggested by Marrero (Engineering Analysis with Boundary Elements 2003; 27: 39-48) is adopted. In the numerical tests, sensitivity analyses are carried out in order to study dynamic characteristics of the HTR-PM nuclear island foundation and to establish fixed base criteria of the supporting soil medium for the associated seismic design of the nuclear island.