A generalized approach for implicit time integration of piecewise linear/nonlinear systems

Abstract

A generalized solution scheme using implicit time integrators for piecewise linear and nonlinear systems is developed. The piecewise linear characteristic has been welldiscussed in previous studies, in which the original problem has been transformed into linear complementarity problems (LCPs) and then solved via the Lemke algorithm for each time step. The proposed scheme, instead, uses the projection function to describe the discontinuity in the dynamics equations, and solves for each step the nonlinear equations obtained from the implicit integrator by the semismooth Newton iteration. Compared with the LCP-based scheme, the new scheme offers a more general choice by allowing other nonlinearities in the governing equations. To assess its performances, several illustrative examples are solved. The numerical solutions demonstrate that the new scheme can not only predict satisfactory results for piecewise nonlinear systems, but also exhibits substantial efficiency advantages over the LCP-based scheme when applied to piecewise linear systems.

Correction Method for the Bending Characteristics of Aero Ball Joints under High Temperature and High Pressure

“…Ball joints have strong non-linear characteristics. In duct stress assessments, a large number of solid ball joint models tend to cause slow or even non-convergent nonlinear iterations [22]. To improve the convergence of the iterative process, a "Joints" connection is often used to simplify the solid ball joint.…”