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1968年,赖斯(J.R.Rice)提出了一个与路径无关的能量线积分,即J积分,其目的是用来分析由缺口或裂纹所引起的应变集中。1972年,贝格利(J.A.Begley)和朗道斯(J.D.Landes)用实验测定了Ni-Cr-Mo-V转子钢和A533B压力容器用钢的断裂韧性J_(Ic),从而提出J_I=J_(Ic)可以作为弹塑性变形下的断裂准则,用它可以预测大范围屈服下裂纹尖端的开裂。从此以来,围绕着J积分的理论、实验和应用,国内外展开了广泛的探索,取得了不少的进展。同时,也存在着很多不同的看法,如何来认识这些问题,关键在于对J积分的定义、特性和物理意义要有深入的了解,这样才能对实验,特别是对J积分的工程应用有一个较为全面、客观的评价。
In 1968, J.R.Rice proposed a path independent energy-line integral, J-integral, which was used to analyze strain concentrations caused by gaps or cracks. In 1972, JABegley and JD Landes experimentally measured the fracture toughness J_ (Ic) of Ni-Cr-Mo-V rotor steel and A533B pressure vessel steels, thereby proposing J_I = J_ ( Ic) can be used as a criterion of fracture under elastic-plastic deformation, which can predict the crack tip at a wide range of yield stress. Since then, a great deal of exploration has been carried out around the theory, experiment and application of J-integral at home and abroad and a lot of progress has been made. At the same time, there are also many different opinions. The key to understanding these problems lies in having a deep understanding of the definition, characteristics and physical meanings of J integrals so as to have a comparatively good application in experiments, especially for J integrals Comprehensive and objective evaluation.