Control of crack propagation in composite fiberglass-polyester laminates using nitinol wire

Abstract

The experimental analysis presents the control of cracked composite fiberglass-polyester by using reinforced Shape Memory Alloy (SMA). SMA wires were used to control and close the crack gap in the composite. The experimental analysis was conducted for one and two SMA wires, whereby these SMA wires were heat treated and trained before being embedded into the fiberglass matrix strip. The composite reinforced strips were pre-notched as a criterion for crack initiation and propagation under gradual tensile loading. It was observed, a complete separation into two pieces of the strip was hindered by the existence of the SMA wires. The control of cracked composite is based on the changing of resistance of the SMA wire during the deformation phase. The variation of the resistance in the stretched SMA wire acts as a feedback to the on-off controller. It was observed during the experimental analysis that when the electric current of 2 Amps is switched on, the wires temperature will be increased until 60??C to produce a contraction effect, hence this effect will close the cracks that occurred under loading condition.