沥青混合料Ⅰ-Ⅱ复合型裂缝的有限元分析

Analysis on Ⅰ-Ⅱ Mixed-Mode Crack in Asphalt mixture Specimen by means of Finite Element Method

利用有限元程序对带预切裂缝的沥青混合料SCB试件进行数值分析,结合断裂力学理论,提出了平面复合型裂缝缝尖应力强度因子Ⅰ,Ⅱ的计算方法及计算公式;分析了平面复合型裂缝缝尖应力强度因子Ⅰ,Ⅱ的影响因素,并拟合出各种角度的裂缝缝尖应力强度因子计算公式;针对裂缝缝嘴及裂缝面的变形情况进行了分析,提出缝尖张开角的计算公式;最后就裂缝塑性区的求解方法进行了初步探讨,并依据裂缝塑区提出了求解裂缝扩展角的一种直观形象方法.

The finite element software was applied to analyze the semi-circular bending（SCB） asphalt mixture specimenwith pre-cutting crack.Combining with fracture mechanics theory,the computation method and computational formulaof stress intensity factors Ⅰ,Ⅱ for planar mixed-mode crack were given.The influence factors of stress intensity factorsⅠ,Ⅱ were analyzed and the calculating formulae of stress intensity factors Ⅰ,Ⅱ for various mixed-mode crackswere fitted out.The deformations of crack mouth and crack surfaces were respectively analyzed and the formulas of open-ing angle of crack tip forⅠ-Ⅱmixed-mode crack were put forward.Finally the method of seeking plastic region for cracktip was simply discussed and a new and visual approach was developed to obtain the propagating angle ofⅠ-Ⅱmixed-mode crack according to the plastic region for crack tip found.