杆系钻机底座结构优化设计

本文在给定结构拓扑和结构几何形状的条件下用序列二次规划的优化方法,研究了杆系钻机底座的结构优化设计.文中给出了底座结构优化设计的数学模型,其目标函数为底座结构的质量,所考虑的约束有尺寸上、下限约束、应力约束、刚度约束、位移约束以及局部稳定约束.文中对设计空间进行了转换,利用曲线拟合得出了单元截面各种参数的关系,使底座结构优化设计的数学模型大大简性.为了提高计算效率,本文采用序列二次规划法避免了灵敏度分析中的复杂计算.还利用Kuhn-Tucker条件,给出了优化算法的增量形式.文中推导了相应的计算公式,给出了计算步骤,并编制了相应的计算机程序.为了验证文中的理论及程序,计算了一个工程实例,该底座有176个节点,265个单元,受三种何载工况作用.优化设计迭代八次收敛,结构质量减少12.6％.这些表明文中所用的理论和方法对杆系钻机底座进行结构优化设计是可行的.

OPTIMUM STRUCTUAL DESIGN OF DRILLING RIG FOUNDATION

The optimum structual design of a drilling rig foundation made up of bars was studied with sequential quadratic programming for specified structual topology and geometry.A mathematical model was given with its objective of minimizing the structual mass and constraints of local buckling in addition to the usual stress,member size and displacement constraints.The relationship between various parameters of element sections was obtained by curve fitting.Stress constraints were converted into quasi-size constrains to simplify the mathematical model.The sequential quadratic programming was utilized to avoid the complex calculation in sensitivity analysis.An algorithm in incremental form was given under Kuhn-Tucker condition.In order to test the theory and computer program developed,an actual drilling foundation with 176 nodes and 265 elements was calculated in contrast with its original design.The calculation converged after eight iterations and the structual mass was reduced by 12.6 percent.