Hygroscopic influence on bistable characteristics of antisymmetric composite cylindrical shells: An experimental study

This paper investigates the effect of moisture on bistable characteristics of antisymmetric composite cylindrical by using experimental and finite element method. The bistable characteristics are characterized by the curvatures of antisymmetric composite cylindrical shells in different stable states and snap processes between the two stable states which are indicated by the load–displacement curve and snap load. The manufactured specimens after dried in the oven are immersed in distilled water to full saturation and the saturated salt solutions (MgCl ₂ ) to full saturation. The specimen achieves different moisture that is immersed in distilled water at the different period until full saturation and in the saturated salt solution (MgCl ₂ ) with the same period of saturation in distilled water. Specimens with different moisture are then mechanically loaded on a testing machine to transform between two stable states. Load–displacement curves are recorded in the computer, from which the snap loads can be found. After the test, the principal and twisting curvatures are captured by a digital image processing. The results are contrasted with hygroscopic influence on another kind of bistable composite structure (asymmetric cross-ply laminates) in this paper. The results show that the shapes and snap loads of antisymmetric composite cylindrical shells are influenced by the moisture increasing.