钝裂纹或缺口下失效评定图的变化及修正方法研究

INVESTIGATIONS OF THE VARIATION OF BLUNTED CRACK AND NOTCH FAD AND ITS MODIFICATION

应用增量理论弹塑性有限元方法以及弹塑性断裂力学 Ｊ积分理论， 深入研究和全面探讨了一种用于含裂纹结构完整性评定的工程方法——失效评定图， 以及钝裂纹或缺口根部曲率半径、缺口长度、缺口端部椭圆离心率、试样形式和材料等对其的影响。提出了钝裂纹或缺口应力强度因子和极限载荷修正方法。通过这一方法建立的失效评定图可有效地消除缺口因素对失效评定图的影响， 由此， 可完全等效地将裂纹失效评定图用于含缺口结构的完整性评定。

An engineering approach, the failure assessment diagram (FAD), for the assessment of the integrity of structures containing cracks is further investigated and fully explored by means of the incremental theory elastic plastic fininte element method and J integral theory of elastic plastic fracture mechanics. The influences of root curvature radius, length (depth) of blunted cracks or notches and the ellipticity of the blunted crack or notch end, and types along with materials of specimens on FAD are investigated more comprehensively. By proposing a modification method to blunted crack or notch stress intensity factors and ultimate loads, the FAD can be established to eliminate the influences of notch factors on it. Therefore, the approach of FAD for cracks could be utilized to the integrity assessment of structures containing notches after modification.