薄壁加筋圆柱壳稳定性分析及优化

    Buckling Analysis and Optimization of Thin-walled Stiffened Cylindrical Shell

    • 摘要: 为了提高薄壁加筋圆柱壳的屈曲承载力,首先,对受轴压作用下的薄壁加筋圆柱壳进行了稳定性分析,在相同体积以及筋条截面尺寸固定的情况下,进行参数化建模,分析了筋条数目对失稳模态和屈曲承载力的影响;进而,以加筋圆柱壳屈曲承载力最大为目标,以纵向筋数目、蒙皮厚度以及筋条截面尺寸为设计变量,建立了加筋圆柱壳等体积下屈曲承载力最大的优化设计模型,用ANSYS APDL语言建立结构参数化分析流程,实现了结构的自动重分析,并采用遗传算法求解优化模型.结果表明:筋条数目对失稳模态和屈曲承载力有很大影响;筋条数目有一个合适的范围,加筋过少,结构的屈曲承载力低于等体积下不加筋光滑圆柱壳的屈曲承载力;加筋过多,随着筋条数目的增加,结构的屈曲承载力也呈下降趋势;通过求解优化模型,可获得最优的筋条数目及筋条截面尺寸,使圆柱壳的屈曲承载力得到显著提高.

       

      Abstract: To improve the load-bearing capacity of buckling for thin-walled stiffened cylindrical shell,the buckling analysis of thin-walled stiffened cylindrical shell under axial compression is carried out.On conditions that the cylindrical shell has the same volume and the section sizes of stiffeners are fixed,the parameterized finite element model is set up to analyze the influence of the number of stiffeners on buckling mode and buckling load.The optimization model of thin-walled stiffened cylindrical shell,which has a constant volume,is developed and solved by genetic algorithms.The objective function of the optimization model is the maximum load-bearing capacity and the design variables include the number of vertical stiffeners,the skin thickness and the section sizes of stiffeners.The structural parameterized analysis process is set up by ANSYS APDL and the automatic re-analysis of the structure is realized.Results reveal that the number of stiffeners has great influence on buckling mode and buckling load.When the stiffeners are sparse,the buckling load of stiffened cylindrical shell is less than that of no-stiffener cylindrical shell with the same volume.When the stiffeners are overcrowded,the buckling load has a downward trend.The buckling load of thin-walled stiffened cylindrical shell is significantly improved because the reasonable number and section sizes of stiffeners are found by using the optimization method.

       

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