Temperature Influence On Bistable Behaviour Of Anti-symmetric Composite Cylindrical Shells

Bistable composite structures, such as anti-symmetric cylindrical shell, can deform from one stable shape to another under an external stimulation induced by mechanical forces, piezoelectric patches, temperature field or SMAs(shape memory alloys). Bistable composite structures have been proposed to generate novel morphing and deployable structures within a range of advanced engineering areas for their favorable load-carrying capability, deformability and light-weight performances.Due to the variation of application environment, the stresses and deformations induced by the temperature play the significant role in the design of the bistable composite structures. To the best of authors’ knowledge, no previous work has been done on the thermomechanical analysis of bistable behavior of anti-symmetric composite shells, which leading to the limit of the shells’ application. The bistable behavior of anti-symmetric composite shells under thermomechanical loading is studied by theoretical analysis, experimental investigation and numerical simulation. As the shell is subjected to the uniform or partial temperature field and through-thickness thermal gradient, the influence on the shell’s bistable behaviour is captured. This provides a feasible approach of controlling the deformation of the bistable shell through adjusting the applied temperature field. The influence of thermal exposure on the shell is also studied by macroscopic and microcosmic methods. The research works on anti-symmetric composite shells are presented as follows:1. Based on the Classical Lamination Theory(CLT) and principle of minimum potential energy, a theoretical model with thermal load is developed. The influence of uniform temperature field and through-thickness thermal gradient on the shell’s curvatures is predicted analytically. The influence factors on the twisting curvature are also discussed.2. During experimental investigation, a testing machine and a temperature box are used with digital image processing technique to study the bistable behaviour under thermal effects. It is shown that the curvatures of the anti-symmetric composite shell grow with temperature increasing, and snap loads decrease in snap-through process and increase a little in snap-back process. Moreover, the curvatures and snap processes also can be influenced by thermal loads on different parts of the shell.3. A finite element analysis(FEA) of the thermal influence on the bistable behavior of the anti-symmetric composite shell is conducted. The variation of the shell’s curvatures and load-displacement curves are obtained similarly to the theoretical analysis and experimental results. Besides, the shape of the shell can be adjusted through imposing single or different combination of uniform temperature field and through-thickness thermal gradients.4. The bistable behavior of the anti-symmetric composite shell after high thermal exposure with different temperature and time is also investigated by the experimental platform. According to the experiment, snap processes and curvatures variation in macro-scale, and the variation of carbon-fiber and epoxy prepreg in micro-scale are received to study the shell’s bistable behavior.