类椭圆截面吊臂的约束扭转特性研究

Study on the thin-walled beam with closed curve boundary section under restrained torsion

综合分析常见椭圆截面和大圆角矩形截面大吨位起重机吊臂结构力学性能,提出了一种类椭圆截面起重机吊臂结构。根据吊臂旋转平面受力状态,可将基本臂简化为闭口曲边截面悬臂薄壁梁力学模型。然后基于乌曼斯基理论,推导了该力学模型的约束扭转特性计算公式。并基于MSC.PATRAN/NASTRAN有限元数值分析验证了理论计算公式的正确性。通过算例分析,获取了一类椭圆截面吊臂的约束扭转翘曲正应力和翘曲位移等重要分析参数。研究表明,推导的理论公式可为类椭圆起重机吊臂的约束扭转分析提供一种简便可行的计算方法。

Comprehensive analysis is done for the structure mechanics perJormance of targe tonnage crane lazy arm with familiar oval section and large rounded rectangle section,and a kind oval section crane lazy arm structure is proposed.According to the stress state of the arm in the rotation plane ,the basic arm can be simplified as a dynamics model of thin-walled cantilever beam with closed and curved edge section. Based on the wumansji theory,the calculate formula for the mechanics model under restrained torsion is derived.Then the correctness of the theoretical calculation formulas is verified based on FEM numerical analysis MSC.PATRAN/NASTRAN.By studying an example,the important analysis parameters are obtained such as the wrap normal stress of restrained torsion,warp displacement.This study provides a feasible com- puting method for the restrained torsion of likeness oval crane arm.