Iterative triangularization of updated finite element stiffness matrices

Summary

In many problems in nonlinear solid mechanics, the finite element method is executed incrementally, with the positive definite stiffness matrix updated after one or more load (or time) increments. In solving the resulting large linear perturbed systems, it is often attractive to use Cholesky triangularization, followed by forward and backward substitution. The present investigation introduces and demonstrates an iterative procedure for updating the triangular factors of the updated stiffness matrix. An approximate convergence criterion is formulated. Simple examples are presented indicating rapid convergence. In the scalar case this method exactly tracks the Taylor series.