  This paper proposes a systematic and novel component level co-rotational (CR)
framework, for upgrading existing 3D continuum finite elements to flexible
multibody analysis. Without using any model reduction techniques, the high
efficiency is achieved through sophisticated operations in both modeling and
numerical implementation phrases. In modeling phrase, as in conventional 3D
nonlinear finite analysis, the nodal absolute coordinates are used as the
system generalized coordinates, therefore simple formulations of the inertia
force terms can be obtained. For the elastic force terms, inspired by existing
floating frame of reference formulation (FFRF) and conventional element-level
CR formulation, a component-level CR modeling strategy is developed. By in
combination with Schur complement theory and fully exploring the nature of the
component-level CR modeling method, an extremely efficient procedure is
developed, which enables us to transform the linear equations raised from each
Newton-Raphson iteration step into linear systems with constant coefficient
matrix. The coefficient matrix thus can be pre-calculated and decomposed only
once, and at all the subsequent time steps only back substitutions are needed,
which avoids frequently updating the Jacobian matrix and avoids directly
solving the large-scale linearized equation in each iteration. Multiple
examples are presented to demonstrate the performance of the proposed
framework.
