一、研究小裂纹扩展特性的意义小裂纹扩展规律的研究是八十年代开始兴起的学科,由于难度较大,因此关于小裂纹断裂力学理论的研究,还有许多方面目前在国内外尚属“未开垦的处女地”,车轴钢表面小裂纹的研究就是其中之一。所谓小裂纹是指裂纹长度很小的表面裂纹、角裂纹及其它类型的微裂纹。例如,根据美国 First, the study of the significance of small crack propagation characteristics Crack propagation is the discipline began to rise in the eighties, due to the greater difficulty, so the theory of small crack fracture mechanics, there are many aspects at home and abroad are still “ Uncultivated virgin land ”, one of which is the study of small cracks on the surface of axle steel. The so-called small cracks refers to the crack length is small surface cracks, angle cracks and other types of micro-cracks. For example, according to the United States