带有中间裂纹载流薄板放电瞬间耦合场的数值模拟

应用耦合场理论采用数值分析的方法计算了具有中间裂纹的导电薄板在放电瞬间裂纹端区域附近的温度场、温度梯度场的分布状态。计算结果表明：由于电流产生的焦耳热源的作用，裂纹尖端处温度瞬时急剧升高，能够在很小的范围内熔化形成微小的口，裂纹前缘的曲率半径增加了几个数量级，显著地减少了应力集中，阻止了干线裂纹源的形成，有效地遏制了裂纹的扩展，数值模拟采用了热－电耦合的分析方法，考虑了材料电阻随温度变化和电流流过生成的内热源间的相互作用，同时考虑了导热系数和比热随温度变化所产生的影响，对于具有中间裂纹的载流反，根据结构、材质、边界条件及通电电流的对称性，计算得到了两个裂纹尖端完全对称的结果。

NUMERICAL SIMULATION OF COUPLED FIELD IN A CURRENT-CARRYING PLATE WITH A CENTRAL CRACK

Based on the coupled thermal-electrical theory, a numerical simulation method is proposed to study the temperature field and temperature gradient field in a current-carrying plate with a central-crack at the moment when the current is switched on. The numerical calculations show that the temperature at the crack tip grows up instantly. The crack tips may be melted, and the welded joints can be formed by metal melting. The radius of curvature around the crack tip will be increased by some orders of magnitude instantly and the stress concentration will be decreased remarkably. Therefore, the formation of the main crack source will be blocked and the crack preventing can be reached. The coupled analysis is performed in the numerical simulation to consider the coupling effects that is due to the fact that the resistance in the electric problem is dependent on temperatures, and the internal heat generation in the thermal problem is a function of the electrical flow.