双材料V型切口断裂研究

Fracture Characterization of V-shaped Notch in Bimaterial

基于双材料V型切口理论,给出了新的双材料V型切口问题的应力强度因子定义,将单材料裂纹问题、双材料裂纹问题、V型切口问题的应力强度因子的定义相统一,进而得到应力外推法计算双材料V型切口KI的计算公式。以单向拉伸和三点弯曲模型为研究对象,研究了双材料中切口深度、泊松比、切口张角变化对应力奇异场的影响,得到了一些相关结论,为异体材料形成的V型切口在应力断料中应用时的参数选取提供了必要的理论依据。

Based on theoretical studies on V-shaped notches in bimaterials, a new definition for the stress intensity factor is proposed, and it is extended to V-shaped notches. A generalized expression of the stress intensity factor is obtained for a crack in single material, a V-shaped notch in single material and a crack perpendicular to bimaterial interface, and then, a formula of stress extrapolation method for calculating the stress intensity factors of bimaterial models is obtained. Taking double edge cracks in a finite plate loaded by uniform tension and three-point bending specimen as examples, the influences of notch depth and notch angle and Poisson ratio on singular stress fields near the V-shaped notch tip are analyzed, some useful conclusions are reached. These results provide theoretical foundations for the application of V-shaped notches formed by dissimilar material to stress blanking.