Influence of pre-strain and position of shape memory alloy wire on buckling properties of smart fibers metal composite

Today fiber metal laminates (FMLs) by having good mechanical properties and low weight have been attention. The use of shape memory alloy (SMA) in the FMLs causes these alloys, under mechanical cyclic loading, by creation reversible hysteresis loop, can absorb or waste mechanical energy and causes amelioration of resistance against buckling instabilities of FMLs. In this study, the effect of increasing pre-strain and embedment SMA wire in far and near layers to neutral axis of FML, under static buckling were investigated. FMLs were contained epoxy resin and glass fibers and 2024-T3 Aluminum alloy. To investigate effect of pre-strain of SMA, the pre-strain of 1, 2 and 3 percent with fixed quantity 6 wires in these FMLs were tested. Due to investigate the position of embedment, the quantity of 4 wires with fixed 3% pre-strain, in far and near layers to neutral axis, are used. The results showed that the increase of pre-strain due to creation more tension of SMA during the fabrication of the specimens and the tendency of wires to return to its original shape during the test makes the structure more resistant against pressure loading. Also, the wires were placed in layers far from the neutral axis of the specimen as compared to near the neutral axis due to the greater effect of the bending resistance of the specimen during the buckling and the effect of the better return properties of SMA wires, causes to increasing resistance against instability and load tolerance limit in FMLs.