Buckling And Dynamical Behavior Of Complex Structures Under Various Loading

This paper consists of two parts. The first one is about the dynamic behavior of stiffened shells under mechanical and thermal loading which is a part of the project "Dynamics of Complex Structures"jointly supported by the Natural Science Foundation of China (NSFC) and China Aerospace Corporation. The second one is about the multiple input random seismic response of complex structures, which is also supported by NSFC. Five aspects are studied in the first part, i.e., 1) Elastic bifurcation thermal buckling analysis of stiffened shells, in which material properties (Young's modulus, Poisson's ratio and thermal expansion coefficient) are changeable due to the thermal loading. For such nonlinear problems, the increment-based iterative strategy is used. 2) Investigation of geometrically nonlinear analysis and post buckling analysis, which are on the basis of the increment-based iterative strategy and the modified Newton-Raphson method. 3) The bifurcation buckling analysis and coupled vibration analysis of structures with the influence of initial stresses taken into account. 4) Transient dynamical response analysis of astronautical structures. The precise integration method is applied and developed to solve this problem. 5) Stationary and non-stationary random analyses of astronautical structures, which are investigated by using and improving the pseudo excitation method (PEM). In the second part, the stationary and non-stationary random response analyses of structures subjected to multiple seismic excitations are investigated. Spatial variations of the ground motion due to the wave passage effect, the partial coherency effect and the local effect are all included. The PEM formulae for multiple input stationary/non-stationary random response problems are derived. Not only the above three effects due to the spatial variations of ground motion are involved, but also the non-uniformly modulated evolutionary random excitations proposed by Priestley are precisely dealt with. When there are too many ground supports, the pseudo excitation method is further improved for both stationary and non-stationary random seismic analyses. Based on uniform seismic excitations, comparisons are made between the random vibration scheme and the response spectrum method stipulated by the Chinese code. This is a valuable exploration for applying the random vibration method to engineering designs.