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基于表面扩散的经典理论及其弱解描述,对曲率、力、电和热共同作用下金属材料内部晶内微裂纹的演化进行了有限元分析。详细讨论了微裂纹初始形态、电场大小、应力大小和电致生热对微裂纹演化的影响。结果表明:对于形态比为的微裂纹,存在一临界电场值c和临界应力值c。当c且c时,微裂纹逐渐圆柱化;当c或c时,微裂纹分节为上、下或左、右两个小裂纹。热应力可减小c的值,即有利于微裂纹分节。同时热应力可加快微裂纹的漂移速度,缩短分节时间。
Based on the classical theory of surface diffusion and its weak solution description, the finite element analysis of the microcrack evolution in the metallic material under the combined action of curvature, force, electricity and heat is carried out. The effects of initial microcrack morphology, electric field size, stress size and electric heat generation on the evolution of microcracks were discussed in detail. The results show that there exists a critical electric field c and a critical stress c for the micro-cracks with morphological ratio. When c and c, the microcracks gradually become cylindrical. When c or c, the microcracks are divided into upper, lower or left and right small cracks. Thermal stress can reduce the value of c, which is conducive to micro-crack section. At the same time, thermal stress can speed up the micro-crack drift speed, shorten the section time.