屈服准则与裂纹开裂判据

本文提出了在裂尖附近的弹塑性交界线上,选择并比较有关的力学参量,以预测复合型裂纹的失稳扩展的方法。分别用Mises,Tresca,Twin shear stsess屈服准则讨论了裂尖附近的塑性区形状与大小,进而在其周界上选择周向应力σ_θ,周向应变ε_θ,塑性区长度γ_P作岛裂纹失稳扩展的控制参量,以预测其失稳扩展的方向及条件。对不同准则与不同控制参量所预测的结果进行了比较。

YIELD CRITERION AND CRACK EXTENSION CRITERION

The shape and size of plastic zone at crack tip is discussed by Mises, Tresca, Twin shear stress yield criterions respectively in this paper. It is pointed out that along the boundary line of plastic zone at craok tip, proper mechaniccal parameters and their amounts are selected and compared to predict the critical extension of the complex crack. Here, corresponding crack critical extension criterions are developed by using the three yield criterions and choosing three parameters, Tomax, Eomax, rpmin (size of plastic ,zone).Predicted results of crack extensimn are compared with eachcritereion,