Thermo-Mechanical Instabilities in Bilaminate Shell Structures

The problem of an elastic bilaminate shell subjected to transverse pressure and a uniform temperature field is considered for plane strain/plane stress configurations. Closed form analytical solutions are obtained for the nonlinear problem, and a stability criterion is derived for situations where multiple equilibrium configurations of the structure are possible for a given value of the loading parameter (a combination of the normalized pressure and thermal moment). Critical behavior is seen to be dependent on two critical parameters, a critical value of the loading parameter and a critical value of the membrane force. Extensive numerical simulations based on these solutions reveal characteristic behavior of the system. This behavior includes, bifurcation buckling, asymptotic buckling, sling-shot buckling and pre-limit point snap-through buckling. It is seen that pre-limit point snap-through is pervasive and perhaps the norm, even for certain classic problems, and its degree is a function of the material properties of the structure.