再制造零件基体裂纹扩展行为研究

再制造毛坯是具有既往服役历史的废旧零件,裂纹扩展严重影响再制造零件的寿命.本文通过试验手段和数值模拟技术对再制造零件基体内部裂纹的扩展行为进行研究,并探寻基体裂纹倾斜角度、裂纹埋藏深度及位置等因素对基体裂纹扩展的影响.研究结果表明:在三点弯曲试验下,垂直裂纹扩展时的临界载荷小于45°倾斜裂纹的临界载荷,更易发生裂纹扩展现象;当裂纹倾斜角度一定时,越靠近试件中心的裂纹越易发生裂纹扩展现象,越危险;而当裂纹形貌一定时,随着裂纹埋藏深度的增加裂纹扩展的临界载荷逐渐增加,且当埋藏深度达到一定程度时,没有出现裂纹扩展现象.经过实验进行对比,实验结果与模拟结果相近,验证了模拟的正确性.

Research on the crack propagation behavior of remanufactured parts

Remanufactured blank is a worn-out part with previous service history. The crack propagation seriously affects the life of remanufactured parts. In this paper, the expansion behavior of the internal crack in the substrate was studied by means of experimental method and numerical simulation. The influence of inclination angle, crack burial depth and location of the crack on crack propagation in the substrate was investigated. The results showed that the critical load of vertical crack was lower than that of inclined crack, and was more likely to incur crack propagation. When the crack angle was certain, the crack closer to the center line of the sample was more dangerous, and more prone to crack propagation. When the crack morphology was certain, with the increase of crack buried depth, the critical load of crack propagation gradually increased. When the burial depth reached a certain value, no crack propagation occurred. The experimental results were similar to the simulation results, and the validity of the simulation was verified.