厚板削斜和纵筋加强非轴对称锥柱结合壳优化

摘要

对于在凹结合壳处采用厚板削斜加强、凸结合壳处采用纵筋加强的非轴对称锥柱结合壳的结构优化设计建立了数学模型.选取凹结合壳处的厚板长度、厚板厚度、厚板削斜长度,凸结合壳处的纵筋剖面参数、纵筋数目、纵筋间距,以及凸凹处的环肋剖面参数等作为设计变量,考虑锥柱结合壳段的内外表面周向应力、内外表面纵向应力、其它部位应力以及工艺性要求等约束,以锥柱结合壳处可变结构的总质量为目标函数.采用APDL语言建立结构的参数化模型,用ANSYS计算结构应力,然后用遗传算法求解优化设计数学模型,解决了非轴对称锥柱结合壳复杂结构的参数化建模和离散变量优化问题.优化的非轴对称锥柱结合壳结构的质量减轻了10.52％.还分析了主要的强度约束条件对优化设计结果的影响.%Mathematical model of optimization for the NCCSTL (non-axisymmetric cone-cylinder shell stiffened with tapered thick plate at the concave location and with longitudinals at the convex location) is described. The main design parameters of the NCCSTL, such as length of the thick plate, thickness of the thick plate, tapered length of the thick plate at the concave location, parameters of the longitudinals, number of the longitudinals, space of the longitudinals at the convex location, and parameters of the circumferential stiffeners at both the concave location and convex location, are selected as the design variables. The total mass of the cone-cylinder shell is defined as the objective function, with the surface stresses of the cone-cylinder shell, technics, and stresses at other locations being considered as the constraints. A parametric model of the cone-cylinder shell is built using APDL (ANSYS parametric design language). Genetic algorithm is employed to execute the structural optimization, and the stresses are calculated by ANSYS. Parametric modeling and structural optimization with discrete design variables of the complex NCCSTL are reached effectively. Numerical simulation shows that the mass of the optimal design of the NCCSTL can be decreased by 10.52%. The influence of the main strength constraints of the structures on the optimal design is also analyzed in the study.