Hygrothermal effect on bistable model of anti symmetric cylindrical  shells and deformation control
                                           PAN Hao, CHAI Guo zhong, ZHANG Zheng*, WANG Chang ming, ZHANG Huan qing
                   (Key Laboratory of E&M., Ministry of Education & Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, China)


Abstract: Aiming at bistable composite structures affected by the variation of the ambient environment, the model of anti symmetric cylindrical shells as a novel kind of bistable composite structure under the effects of temperature and moisture was investigated. A theoretical model of bistable composite structures under the effects of temperature and moisture was developed on the foundation of the classical lamination theory and the minimum potential energy theory. The first stable twisting curvatures, the second stable main curvatures and twisting curvatures of anti symmetric cylindrical shells under the effects of temperature and moisture were predicted by the theoretical model. The load displacement curves in the snap through process, the main curvatures and twisting curvatures with different temperature and moisture were obtained by the finite element software ABAQUS. According to the results of the theoretical analysis and finite element analysis, the results indicate that the twisting curvatures of anti symmetric cylindrical shells in two different stable states increase with the temperature or moisture increasing. The main curvatures in the second stable state and snap loads are influenced slightly by the moisture, but influenced significantly with the temperature increasing. Besides, the feasibility of this method that is presented to active control the twisting curvatures in two stable states with the effects of temperature and moisture is validated.

Key words: carbon fiber composite; hygrothermal environment; finite element method; anti symmetric cylindrical shells; bistable characteristic