Dynamic response tuning of composite beams by embedded shape memory alloy actuators

The thermomechanical performance of a shape memory alloy hybrid composite beam specimen is demonstrated and used in a preliminary validation study of a recently developed constitutive model and finite element formulation for analysis of such structures. A brief description of the thermoelastic formulation is given. A material system consisting of a glass/epoxy matrix with embedded Nitinol actuators was chosen for this study. Results from Nitinol material characterization testing, beam specimen fabrication processes, and base acceleration testing for measuring the dynamic response performance is presented. Selected results from the dynamic tests are shown, interpreted, and compared with predictions from the FE model. Elimination of a thermal post-buckling deflection by the activated SMA was observed. The fundamental natural frequency is shown to increase by a factor of 5.3 and the RMS displacement response is attenuated by a factor 6.4. Preliminary comparisons between predicted and measured performance is good. Discrepancies are attributable to insufficient knowledge of the matrix material properties at elevated temperature.