AgNi10触头材料闭合接触阶段的热-电-力耦合分析及实验研究

摘要:

建立了描述直流闭合接触阶段AgNi10电接触材料受热-电-力耦合作用的数学模型，通过有限元法采用顺序耦合方式计算了固定接触阶段AgNi10触头材料接触区的温度场、应力应变场等，计算过程考虑了材料物理力学特性随温度的变化、接触电阻以及符合实际工作环境的边界条件等。结果表明：电流密度沿接触区域非均匀分布，形成环形热源；在热-电-力耦合作用下，热应力集中区由接触中心向触头内部扩展，同时，接触界面的边缘处也出现了热应力集中区，热应力集中区容易成为裂纹源，这一计算结果与实验现象基本一致。

Abstract:

A mathematic model was established, which described thermal-electric-structure coupling of AgNi10 contact material during DC closed stage. Distributions of temperature field, electric field and stress-strain field were calculated by finite element method. In the calculation process, the sequential coupling mode was adopted. Physical and mechanical properties varying with the temperature and contact resistance were taken into account. And real boundary condition was also considered. The results show that current density is of heterogeneous distribution along the contact interface, and ring heat source is generated; thermal stress concentration zone moves from the contact center to the interior because of effects of thermal-electric-structure coupling; meanwhile, the thermal stress concentration zone appears on the edge of contact interface, and it is easy to become crack source, which is consistent with the experiment.