Modeling and analysis of the ploy region of bistable composite cylindrical shells

Bistable composite cylindrical shells have attracted many attentions thanks to their lightness, simple structure and high packaging efficiency. The ploy region between the two stable states of a bistable cylindrical shell affects the structural properties and overall compactness significantly. An analytical model is proposed assuming that the longitudinal and transverse curvatures are two dominant factors for the two different zones of the ploy region respectively. The model can be used to predict the length and the curvature distributions of the ploy region conveniently. Results obtained from the analytical model agree with numerical and experimental results. The influences of geometric parameters and bending stiffnesses on the ploy region are discussed according to the proposed analytical model.