Abstract:
"Implicit and Explicit Nonlinear Dynamic Analysis of a Large Thin-Arch Dam Using Massively Parallel Computing"
This paper presents and compares implicit and explicit time integration schemes within a parallel Finite Element framework for the nonlinear dynamic analysis of concrete arch dams subjected to earthquake ground motion. The study utilizes a specialized Finite Element Analysis Program (FEAP) to model the complete dam-foundation-reservoir system of the Morrow Point Dam, with the dam and foundation rock discretized using 8-node three-dimensional solid elements and the reservoir modeled with 8-node fluid elements. A key aspect of the model is the inclusion of nonlinearities from the opening and closing of vertical contraction joints, which is simulated using node-to-node contact elements. The entire Finite Element system is parallelized using a domain decomposition method and the Message Passing Interface (MPI) to run efficiently on massively parallel supercomputers. Two primary nonlinear dynamic analysis procedures are compared: an implicit method using the Hilber-Hughes-Taylor algorithm and a Newton method for solving the nonlinear equations at each time step, and an explicit method using the central difference time integration scheme. The performance of both FEA solvers is evaluated on simulations of the dam's response to an earthquake, finding that while both methods produce similar results, the explicit scheme demonstrates superior parallel performance and scalability for this class of large-scale, contact-dominated structural problem.
