Structural analysis of adaptive bistable composites
Maik Gude, Werner Hufenbach, Christian Kirvel Institut für Leichtbau und Kunststofftechnik (ILK), TU Dresden, 01062 Dresden, Germany
Quarterly No. 1, 2008 pages 26-30
DOI:
keywords: unsymmetric, composites, bistable, snap-through, piezoceramic actuator
abstract Anisotropic composites are generally characterised by residual stresses, which primarily occur during the manufacturing at elevated temperature and a subsequent cooling. These residual stresses often lead to a warpage of the composite and in special cases of unsymmetrically built up composites even to large out-of-plane deformations with two stable deformation states. Those so-called bistable composites can beneficially be used for the development of novel adaptive structures if appropriate actuators are integrated, which permit to initiate a permanent change of the composite shape by a snap-through, generated only by a brief energy impulse. For the structural analysis of such adaptive bistable composites based on fibre and textile reinforced thermoplastic or thermosetting matrix systems respectively, a nonlinear semi-analytical simulation model has been elaborated, using a three-stage Ritz method according to the manufacture process of laminate consolidation, actuator bonding and actuator activation. The semi-analytical simulation model enables fast structural analysis of elementary bistable composites and efficient parameter studies. Additionally, numerical simulation models using the finite element analysis have been developed in order to perform a coupled electromechanical structural analysis of the actuator initiated snap-through behaviour of unsymmetric composites with a rather complex structural lay-up and geometry. The simulation models have been validated and were used to design first prototypes of adaptive bistable composites. Manufacture studies and experimental investigation on those prototypes illustrate the successful functional proof of novel intelligent structures and confirm the elaborated theoretical design process.