Integration of computational geometry, finite element, and multibody system algorithms for the development of new computational methodology for high-f

This project aims at addressing and remedying the serious limitations of the three-decade old multibody system (MBS) software technology currently used in the analysis, design, virtual prototyping, and performance evaluation of modern vehicle systems. These limitations are well known and are documented in the literature. The analysis of modern vehicle systems requires the development of complex models that include significant details that cannot be captured or accurately simulated using existing MBS codes which are based on rigid body assumptions or small deformation finite element (FE) formulations that are not suited for efficient communications with CAD systems. It is the main objective of phase I of this SBIR project to demonstrate the feasibility of developing a new MBS software technology that is based on new concepts and algorithms that can be used for accurate and efficient simulation of military and civilian wheeled and tracked vehicle models that include significant details. The new software technology will allow for: 1) preserving CAD geometry when FE analysis meshes are created; 2) modeling large deformation in MBS applications; 3) implementation of general constitutive models; 4) development of new efficient FE/MBS meshes that have constant inertia and linear connectivity conditions; and 5) use of numerical integration procedures that satisfy the constraint equations at the position, velocity, and acceleration levels; these integration methods will not require the numerical differentiation of the forces, and will take advantage of the sparse matrix structure of the MBS dynamic equations. A successful integration of CAD computational geometry (CG), nonlinear large displacement FE, and flexible MBS algorithms is necessary for the development of the new software technology. Such an efficient integration can be accomplished using the nonlinear FE absolute nodal coordinate formulation (ANCF) that allows for preserving CAD geometry, implementing general material models, using general large deformation continuum mechanics approach, developing new FE meshes that have constant inertia matrix and linear connectivity conditions, and exploiting the sparse matrix structure of the MBS dynamic equations. Implicit and explicit numerical integration procedures that ensure that the constraint equations are satisfied at the position, velocity, and acceleration levels will be used in order to avoid violations of the basic mechanics principles.