EFFECT OF SMA TRIGGER ON THE CRASHWORTHINESS OF COMPOSITE TUBES

Base on the shape memory effect of shape memory alloy (SMA) thin wire, three new SMA triggers, called outer-winding SMA trigger, embedded SMA trigger and cross-winding SMA trigger, are designed and made at one end of carbon-fibre reinforced composite tubes. Quasi-static axial compressive tests are conducted on the tubes to investigate the effect of the triggers on the crashworthiness. The results are compared with energy absorption characteristics of tubes with an external bevel trigger for evaluating the triggering effects. It is found that the outer-winding SMA trigger and the embedded SMA trigger have not caused the desirable effect. The triggering effect of the cross-winding SMA trigger is superior to that of an external bevel trigger. In addition, the macroscopic failure mode triggered by the cross-winding SMA trigger is quite distinct from those triggered by other triggers. The change of the macroscopic failure mode enhances the crashworthiness of composite tubes.