Abstract:

Based on the energy principle, by means of the unit force method and the Castigliano theorem, the moment and stress distribution along the S-bend under the given displacement deformation are calculated analytically. According to the calculation, the moment and the stress along the S-bend arise mainly due to the thermal contract, but the gravity effect is nonnegligible. The maximum stress along the S-bend will increase by over 10% after the gravity effect is taken into account. Based on the premise that the height of S-bend is limited, it is found that the smaller the radius of the circles, the smaller the maximum stress along the S-bend, so we can choose the appropriate radius according to the required stress strength and the processing technology during the detailed design. Results shows that the analytical method proposed here is effective and useful for the structure optimization of the practical engineering design.

Key words: ITER feeder S-bend, Energy method, Stress analysis, Structure optimization

摘要：

根据能量方法原理，通过单位力法和卡氏定理分析方法，理论计算得出了给定位移变形条件下沿S弯的弯矩、应力分布。分析表明，沿S弯结构的应力主要由热收缩变形产生，但重力影响也不可忽略，考虑重力影响后沿S弯最大应力较不考虑重力时增大了10%。根据该理论原理编程计算发现，在S弯高度受限的条件下，圆弧段半径越小，结构最大应力越小，实际设计中可根据强度要求结合加工工艺选择合适的圆弧半径。该分析方法为有效优化结构设计提供了理论指导。

关键词: ITER馈线S弯结构, 能量方法, 应力分析, 结构优化