扩展裂纹尖端弹塑性场

本文通过对幂硬化材料中平面应变Ⅰ型裂纹的扩展过程进行精细的弹塑性有限元计算，给出扩展裂纹尖端附近环形区域内弹塑性场的分布。首次提出适用于扩展裂纹尖端环形区域的三项解。其中旨项为ＨＲＲ奇异解；第二项反映三轴应力的强弱；第三项与ＨＲＲ奇异性项相比还含有线性项，并指出：扩展裂纹尖端环形区域弹塑性应力应变场的分布和强弱可由Ｊ－Ｑ－ｋ＿２三参量刻划。此结论适用于不同试样几何，不同材料硬化指数以及由小范围屈服至全面屈服的不同屈服程度。

ELASTIC-PLASTIC FIELDS NEAR THE GROWING CRACK TIP

In this paper,the propagation process of a crack in the power-law hardeningmaterials is accurately calculated by the elastic- plastic finite element method under planestrain and Mode I conditions. The elaistic-plastic fields near the growing crack tip are givenin detail.A unified three term solutions of stress fields ahead of the growing crack tip are firstpresented. The firs t term is t he H RR singularity solut io n. T he second t erm describes thetriaxiality The third term includes a linear term of the radius coordinate r besides the HRRsingularity term.Th is conclusion is completely sat isfied for t he various sp ecimen geometries, differentmaterials and a variety of yielding degrees from small scale yielding to large scale yielding.