摘要
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 methods for analyzing the thermal buckling have the restrictions on dealing with the buckling of the complex plate-shell structures under the coupling of the thermal and mechanical loadings. The rational methods for analyzing the thermal buckling are conducive to improving the plate-shell design level. In the light of the above understanding,according to the structural and mechanical characteristics of high temper-ature plate-shell,under the hypothesis of the effects of the mechanical loadings equivalent to the local boundary stress,four kinds of local thermal buckling theoretical models were firstly proposed. The post-buckling behavior of the complete plate-shell and the one with initial defects were studied based on initial post-buckling asymptotic analysis theory. Pre-loaded four edge simple-supported model, pre-loaded four edges clamped model, pre-loaded three edges simple-supported one edge free model,pre-loaded three edges clamped one edge free model were studied in detail. The effects of structural geometry parameters （the length,thickness,etc.） on the post-buckling behavior of plate-shell structures were investigated and were extended to the solution of the high order thermal buckling problem. The results have shown that the buckling type of plate structure is bifurcation , and the shell structure’s is jumping. And under the constant length-width ratio,the critical load of buckling follows the rules that it decreases as the length increases while it increases as the thickness increases.
出处
《推进技术》
EI
CAS
CSCD
北大核心
2015年第2期285-291,共7页
Journal of Propulsion Technology
基金
中国博士后科学基金
关键词
高温
板壳结构
局部热屈曲
后屈曲
High temperature
Plate-shell structure
Local thermal buckling
Post-buckling
