Investigation On Thermal Buckling Behavior Of Composites Thin-wall Cylindrical Shell

The emergence of new materials has brought more opportunities for the aerospace, automotive, medical and other fields to develop toward more high-tech industries. However, it also leads to many problems in the process of wide application, such as, the complicated mechanical behavior is an important research focus concerned by people, especially the thermal buckling behavior has becoming a hot and difficult research issue. Therefore, the concern of the thesis is to establish the theoretical solution of the critical temperature rise about a thin-wall cylindrical shell subjected to the uniform temperature rise based on Donnell Thin-wall Cylindrical Shell Theory. The thermal buckling behaviors of the metal, functionally graded materials(FGM) and fiber resin materials were investigated. The main works and related conclusions are as follows:(1) According to the simplification criteria of Donnell and Timoshenko method, the theoretical solution of the critical temperature rise for the metal thin-wall cylindrical shell under the uniform temperature rise was derived by integrating the geometric equations, physical equations, equilibrium equations and boundary conditions. And then, the eigenvalue value, also is named as the critical temperature rise of metal thin-wall cylindrical shell under uniform temperature rise load was calculated using finite element method. Finally, a modified coefficient was proposed for improving the theoretical solution of the metal thin-wall cylindrical shell.(2) According to the Timoshenko method and von Mises method respectively, two kinds of theoretical solution of the thermal buckling for an FGM thin-wall cylindrical shell subjected to the uniform temperature rise were deduced. The results showed the calculated deviation of the two methods was less than 1%, which indicated the consistency of the two theoretical solutions. At the same time, the eigenvalue value of FGM thin-wall cylindrical shell was calculated using finite element method. Finally, another modified coefficient was also proposed for improving the theoretical solution of the FGM thin-wall cylindrical shell.(3) According to the simplification criteria of Donnell, the theoretical solution of the critical temperature rise for a thin-wall cylindrical shell made of the fiber resin was derived based on the von Mises method. And then, the eigenvalue value of the thin-wall cylindrical shell made of fiber resin was calculated by using FEM, and the results showed the deviation between theoretical solution and the numerical solution was less than 16%, which resulted from the anisotropy and winding angle of the fiber resin material.(4) According to the theoretical and numerical analysis, it indicated that the critical temperature rise of the metal material thin-wall cylindrical did not vary with elastic modulus of the material, and the critical temperature rise of the FGM thin-wall cylindrical shell was increased with the increment of power index. Otherwise, the critical temperature rise of the three kinds of materials thin-wall cylindrical shell were not relevant to the geometric length of the shell, and inversely proportional to the radius of the shell.