Nonlinear Tensile and Shear Behavior of Macro FiberComposite Actuators

摘要

The Macro Fiber Composite actuator, developed at the NASA Langley Research Center, offersrnmuch higher flexibility and induced strain levels than its monolithic piezoceramic predecessors. Thisrnincreased performance results from a laminated, piezoceramic fiber-reinforced construction and anrninterdigitated electrode pattern. Since the Macro Fiber Composite is capable of such high actuationrnstrain levels, (~2000 με, peak-to-peak), a significant amount of nonlinear mechanical behaviorrnoccurs. As a result, the mechanical properties are not constant over the entire applicable strainrnrange of the device, and such changes should be accounted for in structural actuation models. Therncurrent work presents the results of MFC tensile tests designed to measure, under short circuitrnboundary conditions, both the four independent linear elastic engineering constants, valid at mostrnstrain levels, as well as nonlinear stress-strain behavior. In addition to experimental results, variousrnplastic deformation models are developed to represent this constitutive behavior at higher strainrnlevels.