MECHANICAL ANALYSIS OF BI-STABLE CYLINDRICAL SHELL STRUCTURE

Bi-stable structure can be stable in both the extended and rolled-up configurations. As a novel deployable structure, it shows a broad application prospect in the field of aeronautics and civil engineering, etc. A deformed isotropic structure has no bending-stretching and twisting-bending coupling. However, if made unstressed from isotropic materials it is only stable in the initial configuration. So pre-stressed isotropic cylinder shell model is proposed. This model illustrates the effect of pre-stress on bi-stable behavior of such structure. The conditions for bi-stability of isotropic cylindrical shell are derived based on the principle of the minimum strain energy. Meanwhile, a finite element analysis of the process of rolling up a bi-stable cylindrical shell is performed using the ABAQUS package. The results of this simulation provide considerable new insights into the structural mechanics of bi-stable shell, as well as predicting the stress distribution, curvature variation, etc. in the rolled-up shell. Furthermore, a deformed isotropic cylindrical shell without or with pre-stresses has its two equilibrium positions where there is never twisting deformation. For the former, the first equilibrium position of the shell is stable while the second is unstable. However, a pre-stressed shell will have its bi-stable states if the acting pre-stress satisfies some confined conditions, and it has two opposite curvatures corresponding to the two stable states.