ASSUMED MODES METHOD AND ARTICULATED FLEXIBLE MULTIBODY DYNAMICS

The use of assumed modes in articulated flexible multibody dynamics algorithms requires the evaluation of several domain-dependent integrals that are affected by the type of modes used. The implications of these integrals-often called zeroth, first-, and second-order terms-are investigated in this paper for arbitrarily shaped bodies whose modal models may be obtained using finite element analyses. Guidelines are developed for using appropriate boundary conditions when generating the component modal models. It is shown that the Issue of which body reference frame to use is intimately related to the question of what type of component body modal models must be selected. The issues of whether and which higher order terms must be retained are also addressed. Analytical results, and numerical results using the Shuttle Remote Manipulator System as the multibody system, are presented to qualitatively and quantitatively address these issues.