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传统高温板壳结构的热屈曲分析方法,在解决热-机械载荷耦合作用下复杂板壳结构的屈曲问题时存在较大的局限性,合理的局部热屈曲理论分析方法有助于提高板壳热结构设计水平。因此,根据高温板壳的结构特征和力学特征,在“机械载荷等效成局部边界压应力效应”假设前提下,提出了四种典型的应力等效的局部热屈曲模型,基于初始后屈曲渐近分析理论,建立了一套有效的局部热屈曲理论分析方法。采用上述方法,研究了完善和具有初始缺陷板壳的弹性热后屈曲性态,具体分析了带预载的四边简支模型,带预载的四边固支模型,带预载的三边简支、一边自由模型以及带预载的三边固支、一边自由模型,给出了板壳长度尺寸、厚度等参数对热屈曲载荷的影响规律,并将其推广到高阶热屈曲问题中。分析结果表明:板体现为分叉式屈曲,壳体现为跳跃式屈曲;在长宽比一定的情况下,长度越长,屈曲临界载荷越小,厚度越厚,屈曲临界载荷越高。
The traditional method of thermal buckling analysis of high-temperature shell structure has great limitations in solving the buckling problem of complex plate-shell structure under thermo-mechanical load coupling. The reasonable local theory of thermal buckling can help to increase the heat Structural design level. Therefore, four typical stress-equivalent local thermal buckling models are proposed based on the structural and mechanical characteristics of the high-temperature shell under the assumption that the mechanical load is equivalent to the local boundary compressive stress effect. Based on the initial Buckling asymptotic analysis theory, established an effective method of local thermal buckling theory. By using the above method, the elastic post-thermal buckling behavior of the shell with initial imperfections is studied. The four-sided simply supported model with pre-load, the four-sided model with preload and the three-sided simple support with preload , A free model and a free-form model with three sides supported by preloading are given. The influence of parameters such as the length and thickness of the shell on the thermal buckling load is given and extended to the high-order thermal buckling problem. The results show that the plate is bifurcated buckling and the shell is in the form of jumping buckling. When the aspect ratio is constant, the longer the length, the smaller the critical buckling load. The thicker the buckling, the higher the critical buckling load.