Empirical model reduction of geometrical constrained gossamer structures

Abstract

In recent years, the use of membranes for space craft applications has attracted a great deal of attention, as so called gossamer structures. However gossamer structures do not have practical applications at present. One problem in space research is design time reduction. Currently, JAXA is working on a spin type solar power sail spacecraft. Computational analysis of the sail membrane's complex mathematical model is difficult and time consuming. Therefore this has a negative impact on design problems. The model reduction technique is required. With a feasible shortened computational analysis period, a trade-off would be possible when designing and determining the operation procedure. It is a necessary tool in order to put the gossamer structure to practical use. The authors have already suggested a possible benefici al effect of the empirical model reduction for gossamer stru crure. Unfortunately the method couldn't deal with the geo metric constraint, for example rigid body with cable constra int. The purpose of this research is to construct a reduction model of geometrical constrained gossamer structure. Generally, the equations of motion of gossamer structures are highly nonlinear and stiff differential equations. For this reason we employ the geometrically nonlinear FEM code. The code is based on the energy momentum method (EMM), so the numerical time integration is unconditionally stable. In this paper, we constructed a penalty method for the geometrical constraint based on the EMM. This permits expression of the geometric constraint in a model. It is possible to apply empirical model reduction techniques to this mathematical model. This can make constructing of a reduction model including geometric constraint. We will show the reduction model can approximate the full-order model with sufficient accuracy. Copyright (c) 2010 by JSME.