From a general point of view, the proposed work will involve the development, implementation and evaluation of a general object- oriented framework for use in nonlinear dynamic structural finite element analysis. This framework will consist of sets of classes of objects modeling nodes, elements, degrees-of-freedom, materials and so on. In light of the special issues surrounding nonlinear dynamic analysis, the classes will be designed with the following goals in mind: to allow flexibility in algorithm selection, implementation, and distribution; to be well-suited for parallel implementation; and to function well in an interactive environment with respect to model development, modification and visualization. To achieve these goals, several key components will be used: coordinate-free geometry, iterative techniques for solving systems of equations; and an element-by- element implementation strategy.//
