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基于表面弹性理论和保角映射技术,研究了远场作用反平面剪切载荷作用下考虑表面弹性效应时正三角形孔边裂纹问题的断裂性能.给出了孔边应力场的精确解,获得了裂纹尖端应力强度因子的解析解答.数值算例中讨论了裂尖应力强度因子随三角形孔尺寸、裂纹长度和表面性能的变化规律.结果表明:当三角形孔的尺寸在纳米量级时,无量纲应力强度因子具有显著的尺寸效应;随着三角形孔尺寸的增大,论文结果趋近于经典断裂理论解答;无量纲应力强度因子随孔边裂纹长度的增加,先增大而后减小;当孔边裂纹长度较小时,表面效应影响较弱;应力强度因子的尺寸效应受表面性能影响显著.“,”Engineering structures and mechanical parts often contain hole defects,such as bolt holes,rivet holes,groove holes,weight loss holes,etc.Under extreme loads and severe service conditions (e.g.high temperature,high speed and vibration),they are prone to stress concentration phenomena and fatigue cracks along the holes.Therefore,it is of practical significance to study the fracture behavior for the problems of cracked holes.When the size of cracked hole is on the order of nanometer,the surface effect plays an important role in the elastic field around the defects (hole and crack).In this work,based on the theory of Gurtin-Murdoch surface model and a conformal mapping technique,a theoretical study is conducted on the fracture behavior of cracked equilateral triangular hole with surface elasticity effect under far-field antiplane shear.An exact solution of the whole-field stress around the triangular hole is presented.An analytical solution for the stress intensity factors at the crack tips is obtained.Numerical examples are provided to discuss the variation of the dimensionless stress intensity factor with size of the triangular hole,length of crack and surface property.The major results show that when the size of triangular hole is on the nanometer scale,the dimensionless stress intensity factor exhibits a significant size effect.The present solution approaches the classical fracture theory with the increase of the size of triangular hole.With the increase of crack length,the stress intensity factor first increases,then decreases.When the length of crack is small,surface effect of the defect is quite weak.The size-dependent effect of the stress intensity factor is significantly affected by the surface property.The exact solution presented is helpful in understanding the fracture behavior of cracked holes in nanoscale and the structural integrity assessment.