框架的非线性有限元优化设计

充分考虑了钢筋混凝土材料的非线性特征 ,在用二次积分迭代法进行R C 框架非线性有限元分析的基础上 ,进行框架结构造价最省为目标的优化设计。此法可以反映单个构件裂缝开展、钢筋屈服、混凝土被压碎、内力重分布等全部过程。非线性优化设计采用整体优化和分部优化相结合的优化方法 ,将非线性分析和系统优化紧密结合。分部优化的数学模型被有效简化 ,但充分考虑截面尺寸、纵向钢筋和箍筋这些在造价中起决定作用的设计变量和各种抗震约束条件 ,优化结果较精确。非线性有限元优化程序将非线性分析与系统优化穿插在一起 ,联合迭代 ,共同收敛 ,有效减少了迭代的次数。通过优化设计实例证明 ,非线性有限元优化设计的造价比弹性的优化设计有显著地节省。

THE OPTIMIZATION DESIGN OF FRAMES BASED ON THE NONLINEAR FINITE ELEMENT ANALYSIS

Based on the double integration interative method for the nonlinear finite element full\|range analysis of R.C.frame, an optimization design of frames is proposed for the least cost of project.The double integration method can fully consider the nonlinear feature of reinforced concrete and imitate the entire procession of crack development, reinforcement yielding, concrete crushing and internal force redistribution.The integral optimization and the partial optimization are applied for the combinations of the partial optimization and system optimization.The mathematics model of the partial optimization is simplified, but still includes variety of anti\|seismic design constraints and critical design variables such as section dimensions, bars and stirrups. So the results of the optimization are comparatively reasonable and precise. Nonlinear analysis and system optimization are jointed together, iterated and converged mutually in nonlinear finite element optimization program, which in effect reduces the times of the iteration.An example of optimization design has proved that the cost of a nonlinear finite element optimization design would become less than that of a linear optimization design.