加筋圆筒结构重量和屈曲承载力关系的量化分析

Quantitative Analysis of Structural Weight and Buckling Bearing Capacity of Stiffened Cylinder Structure

加筋圆筒结构对轻量化程度要求高,通过量化分析其屈曲承载力与重量关系为工程早期设计提供参考。首先,探究了加强筋数量或截面类型等单因素变化引起的结构重量变化对其屈曲承载力的影响。进而,以加强筋数量、截面类型、尺寸为设计变量,约束屈曲承载因子下限,建立结构重量最小化的优化模型,探究这些多因素同时变化时加筋圆筒结构重量和屈曲承载力关系。在此分析和优化设计中,采用有限元法计算结构屈曲承载因子,为了获得屈曲承载力和重量关系,在优化设计中引入不同屈曲约束下限获得多组优化设计解,基于最小二乘法拟合出结构屈曲承载力和重量关系曲线。结果表明,在给定设计域、边界约束、载荷工况下竖向加强筋比周向加强筋对结构屈曲承载力影响大,加强筋不同截面类型与重量变化关系不同。结构屈曲承载力与重量关系曲线为非线性,随着结构重量增大屈曲承载力增大,但其增大的幅度逐渐减少。

Stiffened cylinder structure requires high lightweight level.The reference for early engineering design by quantitative analysis of the relationship between buckling bearing capacity and weight was provided.Firstly,the influence of structural weight changes caused by single factor changes such as the number of stiffeners or section types on the buckling bearing capacity was explored.Furthermore,the number of stiffeners,section types and sizes were selected as design variables,the lower bound of buckling load factor was constrained,and the optimization model of structural weight minimization was established to explore the relationship between structural weight and buckling bearing capacity of stiffened cylinder when these multiple factors change at the same time.In the analysis and optimization design,the finite element method was used to calculate the buckling load factor of the structure.In order to obtain the relationship between buckling bearing capacity and weight,different lower bounds of buckling constraints were introduced in the optimization design to obtain multiple sets of solutions,and the curve of buckling bearing capacity and weight was fitted based on the least square method.The results show that under the given design domain,boundary constraints and load conditions,vertical stiffeners have more important impact on the buckling bearing capacity of the structure than the circumferential stiffeners.The relationship between stiffeners of different cross-section types and weight is inconsistent.The relationship curve between the buckling bearing capacity and the weight of the structure is nonlinear.With the increase of the structural weight,the buckling bearing capacity increases,but as the unit weight increases,the corresponding increases in buckling capacity decreases gradually.