A novel nonlinear finite element method for structural dynamic modeling of spacecraft under large deformation

Abstract

An accurate structural dynamic model is significant for control system design and safety of the spacecraft. Traditional linear structural dynamic models mostly based on the hybrid coordinate method, requiring the existence of central rigid bodies and the satisfaction of the small deformation assumption. However, modern spacecraft are utilizing more and more flexible structures and payloads, leading to a possibility of non-rigid-body tendency and large deformation, which needs a nonlinear solution. Existing nonlinear finite element methods become difficult to implement structural analysis for spacecraft due to the high degrees of freedom of the elements. Therefore, this paper proposes an accurate, freedom-reduced, universally applicable, and full-flexible nonlinear finite element method for modern spacecraft based on the continuum mechanics, taking the triangular element as an example. Simulations verify that this method can effectively solve the structural motion of large deformation, and is able to calculate the time-domain response under typical loads such as concentrated forces, body forces and torques.