An investigation on the static buckling behavior of laminated cylindrical composite shells with embedded SMA wires by experiment

In the present work static buckling behavior of laminated cylindrical composite shells were investigated experimentally. The laminated composite shells were fabricated from carbon-epoxy composite by filament winding process. The stacking sequences were +55˚/-55˚/SMA/+55˚/-55˚ and +75˚/-75˚/SMA/+75˚/-75˚. The superelastic SMA wires placed between plies 2 and 3 of the four layers laminate. Shape memory alloy wires were used in the middle of the composite in two cases, without pre-strain and with 5% pre-strain. All of buckling test were performed using 2.5 ton universal test machine with crosshead speed of about 0.1 mm/min. The buckling tests were arranged with two kinds of boundary conditions, simply supported- simply supported and clamped- clamped boundary conditions. Several tests were done to achieve the mechanical properties of composite shells, like standard tensile test of the resin samples, mechanical tensile test of the nol ring, tensile test of the unidirectional composite samples and the tensile test of the superelastic shape memory alloy wire. The experimental buckling analyses of the cylindrical composite shells with embedded superelastic SMA wires show that the critical buckling load increased by using the SMA wires. Also, in the laminated composite with stacking sequences +75˚/-75˚/SMA/+75˚/-75˚, the buckling load of shells was increased. In addition the buckling capability of composite shells in the simply supported- simply supported boundary condition is greater than the clamped- clamped boundary condition.