Flexible matrix composite actuators

Flexible matrix composites (FMCs) consist of highly extensible, flexible elastomers reinforced by relatively inextensible, stiff fibers. FMCs are particularly promising materials for large structural deformation applications. One possible application is to use FMCs to construct cylindrical, pressure driven actuators. These cylindrical FMC actuators demonstrate various actuation behaviors (extending, contracting, and twisting) when pressurized, depending on the lamination configuration of the membrane. Special interest is given to the contracting type actuator because of the mechanical advantage it provides, and its analogy to muscle function. By using a continuum mechanics approach, a finite axisymmetric deformation model is developed to model the behavior of contracting type FMC actuators during pressurization. This model combines large deformation membrane theory and large deformation theory for laminated composites and is capable of including material nonlinearity and geometric nonlinearity that arise from large deformation and fiber reorientation. The behavior of FMC actuators under various loading conditions are discussed based on the proposed model. Methods to integrate multiple FMC actuators to build interesting active structures are proposed. A finite element model is used to predict the morphing behavior of a plate-shaped active structure for small deformations.