QUASI-NEWTON ITERATION IN NON-LINEAR STRUCTURAL DYNAMICS.

In the context of nonlinear structural dynamics, implicit methods of solutions involving the tangent stiffness matrix are often not competitive with explicit schemes, due to the cost of the numerous updates of an iteration matrix which are generally required for a satisfactory rate of convergence. In an attempt to reduce this cost, the application of quasi-Newton methods is proposed: the underlying idea is to use an approximation to the inverse iteration matrix in place of the true inverse.