Debris Impact Analysis of Large-scale Space Structures by Using ASI-FEM.

Abstract

In this paper, the Adaptively Shifted Integration (ASI) technique with the linear Timoshenko beam element, which can be easily implemented with a minimum effort into the existing finite element codes, is applied to the debris impact analysis of framed structures in space. In this technique, the numerical integration point in an elastically deformed element is firstly placed at the optimal point for linear analysis. Then the integration point is shifted immediately after the occurrence of a fully plastic section in the element, using the previously established relations between the location of numerical integration point and that of plastic hinge, to form a plastic hinge exactly at the position of that section. The technique prouduces higher computational accuracy with fewer elements than the conventional finite element code. By expressing member fracture by a plastic hinge located at the exact position with a simultaneous release of resultant forces in the element, discontinuous problem such as this kind can be easily analysed even by the finite element code with the displacemental form. Contact between members, and the distribution of element mass before and after member fracture has occurred, are also examined. By using the algorithms described in this paper, sufficiently reliable solutions have been obtained in the debris impact analyses of a space module unit and the International Space Station, which is due to be constructed from November. 1998.