Buckling analysis of hybrid laminated composite cylindrical shells reinforced with shape memory alloy fibers in thermal environment

High-speed flying objects are subjected to temperature variation caused by aerodynamic heat, which reduces flight performance due to instability. Due to high tensile force generated by increasing temperature, Shape Memory Alloys (SMA) may be used to reinforce these structures. In this study, the axial buckling of composite cylindrical shells reinforced with SMA fibers made of Nitinol is studied. Properties of SMA fibers are determined using the Brinson's constitutive model. Governing equations are derived using classical shell theory with the Von-Karman type of geometrical non-linear in conjunction with Love's first approximate accompanied with the static mode of virtual displacement principle. To solve the governing equations generalized differential squares method are used in longitudinal direction. The effect of pre-strain, volume fraction and position of SMA fibers on the critical load of the cylindrical shells are investigated. Results show that shell reinforcement with small percentage of pre-strained SMA fibers significantly increases the critical load. Also, the use of SMA fibers in the longitudinal direction and in the layer close to the inner surface of the cylinder has a favorable result in increasing the critical load.