Dynamic folding analysis for multi-folding structures under impact loading

The authors review the basic mechanisms for folding structures, such as a combination of pantographs which have unstable states under dynamic loading. The problem is considered in terms of the large displacement range within which a truss is allowed to be foldable and deployable, in the context of elastic stability and allows for dynamic control. There are several possible folding patterns that are identified at the unstable states and the authors put forward a new concept for this multi-folding of a pantograph structure using a simple model. The authors explore the critical dynamic and postbuckling effects through the concept of energy minimization. For comparisons with final large-deflection fold patterns, the authors use an original program for dynamic truss analysis. They demonstrate that the fold patterns change as a function of both the velocity of the dynamic loading and the dynamic geometry of the structure. (C) 2007 Elsevier Ltd. All rights reserved.