多圆孔边裂纹应力强度因子复变函数解

COMPLEX VARIABLE FUNCTION SOLUTIONS OF STRESS INTENSITY FACTORS FOR MULTIPLE HOLE-EDGE CRACKS

飞机机身蒙皮结构多紧固件,孔边裂纹扩展过程中的加速效应主要表现为多条疲劳裂纹之间应力强度因子的相互干涉。基于Muskhelishvili复变函数理论和有限截项原则,提出一种修正的近似迭加方法,用于求解远场应力作用下的多圆孔边裂纹应力强度因子,并分析了双孔等长裂纹、双孔不等长裂纹、三孔等长裂纹、三孔不等长裂纹等四种开裂模式的应力强度因子变化规律。算例表明,随着相邻裂纹尖端逐渐趋于接近,裂纹间的干涉效应表现明显,无量纲应力强度因子快速增加。

The acceleration effect in the process of collinear hole-edge cracks propagation of aircraft fuselage skin structure is mainly manifested by the interaction of stress intensity factors between multiple fatigue cracks.A modified approximate superposition method based on the Muskhelishvili complex function theory and truncated conformal mapping approach is proposed in this paper to solve the stress intensity factors of multiple hole-edge cracks under remote uniform tension.The influence law of stress intensity factors for three kinds of cracking mode is analyzed,including the cracks of equal length emanating from two holes,the cracks of unequal length emanating from two holes,the cracks of equal length emanating from three holes and the cracks of unequal length emanating from three holes.The results of examples show that the interaction between adjacent cracks is obviously and the dimensionless stress intensity factors increase rapidly when the crack tips approach each other.