Flexible multibody analysis of thin structures with actuated components.

摘要

A multibody system consisting of rigid bodies, flexible bodies and various joints is called a flexible multibody system. When constructing a numerical model of a flexible multibody system, the simulation tool needs to be able to adequately represent the physical characteristics of the system. In particular, structural flexibility plays a fundamental role in the behavior of many modern mechanical systems. Space structures often comprise thin structures that are in relative motion with respect to one another, resulting in variable geometry systems that are truly multibody in nature. Low cost, accurate simulation tools are essential for the comprehensive analysis of these multibody systems. The overall goal of the present work is to develop a general, finite-element-based nonlinear multibody analysis tools for the simulation of static and dynamic responses of flexible multibody systems containing membrane or shell elements. To achieve this goal, a geometrically exact, nonlinear shallow shell model is developed. It features the following characteristics: anisotropic linear or possibly nonlinear elastic material, large displacements and rotations but small strains, actuation by hygrothermal effects or piezoelectric materials. A pre/post-processor to recover the three dimensional stress fields of a plate using the variational asymptotic method is implemented. A membrane model for flexible multibody analysis is developed. It features the following characteristics: anisotropic linear or possibly nonlinear elastic material, large displacements but small strains, actuation by hygrothermal effects or piezoelectric materials. Robust and rigorous time integrators, the Energy Preserving and Energy Decaying schemes, are developed for the shell and membrane model. Application of the proposed multibody dynamic analysis tool to a realistic inflatable space structure is demonstrated.