Effect of pre‐tension on tensile strength of glass fibers‐epoxy composite reinforced with shape memory alloy wire

In this study, the potential of superelastic shape memory alloy (SMA) wire to enhance the tensile strength of a glass fibers reinforced epoxy composite was evaluated. Composite specimens with one embedded SMA wire fabricated with hand-layup method. The specimens were placed under tensile loading (pre-tension) and unloaded before ultimate tensile strength. The pre-tension amounts were 65, 75, and 85% of ultimate tensile strength. After unloading, SMA wire wants to transform to the austenite phase and recover its primary shape and a large amount of compressive stress will be released over the composite specimens. Results show that the ultimate tensile strength for specimen with 75% pre-tension was 32% higher than the composite without pre-tension. This pre-tension has the best effect on ultimate tensile strength and pretension of specimens before ultimate tensile strength leads to higher tensile strength due to the high superelasticity of the SMA wires.