基于MSC.Nastran优化梁元偏置的分析

Analysis of the Beam Eccentricity Based on MSC.Nastran Optimization

在有限元结构设计分析中,对梁的受力形式以及在空间放置方式等的理解直接影响整个分析计算结果。文中将加筋板离散为板元和梁元,用大型通用有限元商业软件MSC.Nastran的SOL200优化了梁元考虑偏心和不偏心的4种工况,其结果满足位移和应力约束。对几种工况中优化后的加强筋的不同尺寸,表明存在巨大差异,且符合真实物理模型的有限元模型,即带梁元偏心的情况质量达到了最轻。将优化结果参数用于原模型,用MSC.M arc进行了模态分析,并比较了前三阶模态。最后,得出了结论,如设计中不考虑梁元偏心,会给梁元尺寸的优化结果带来极大的误差,并对刚度的影响也不可忽略。考虑梁元偏置的加筋板不仅具有最小质量,而且具有广泛的实用价值。

In finite element engineering analysis of structures, the supporting form and placing mode of the beam influence analytic results directly in three-dimensional space. In this paper, the stiffened panel is made up of the shell and beam elements in MSC. Patran. Structural optimization is carried out by SOL200 according to four cases, which considers the beam eccentricity and no beam eccentricity. The results satisfy the displacement and stress constraints. Comparing with several cases of the dimensions of the stiffeners after optimization, there are huge differences indicated among them and the stiffened panel with the beam eccentricity obtains the minimum weight only in the actual case. Calculation results of the optimization parameters are utilized to analyze the modes in MSC. Marc. In comparison with several cases of the first three set frequencies, the diversities of the stiffness are discovered. The conclusion is eventually reached, of which the optimization results will create the huge errors and the influences of the structural stiffness are not ignored if the beam eccentricity is not considered, in the paper. Not only has the stiffened panel with the beam eccentricity the minimum weight, but also it has the broadly useful value.