基于能量密度等效的Ⅰ-Ⅱ型裂纹K因子半解析模型

Semi-analytical Method for Solving the Stress Intensity Factor of ModeⅠ-ⅡCrack Based on Energy Density Equivalence Principle

应力强度因子K是控制脆性断裂与疲劳裂纹扩展行为的重要力学量,历史上各类裂纹试样的K因子计算方法与公式都较复杂,所得到的KⅠ和KⅡ表达式为不同形式的回归式,公式的适用范围有限。针对含Ⅰ-Ⅱ混合型裂纹的试样,基于能量密度等效原理提出求解Ⅰ-Ⅱ混合型裂纹的K因子半解析模型,模型参数少,形式简单,普适性强,适用范围广。半解析模型预测的应力强度因子与文献结果和有限元结果吻合,该模型为脆性断裂与疲劳裂纹扩展行为相关研究提供了重要的理论基础。

The stress intensity factor is an important mechanical parameter for controlling the behaviour of the brittle fracture toughness and fatigue crack growth.In the past researches,methods and formulas for solving K-factor of various cracked components are complicated.The expressions of KⅠand KⅡare both different fitting expressions,which have a limited application.A semi-analytical model with a simple form and general applications to predict K-factor for components with modeⅠ-Ⅱcrack is proposed based on energy density equivalence principle,and parameters can be calculated by a few FEA calculation.The result shows that K-factor predicted by the semi-analytical model agrees well with the literature result and the FEA result,and the model provides important theoretical foundation to studies on the brittle fracture toughness and fatigue crack growth.