基于串并联弹簧模型的混凝土黏聚律及裂缝扩展全过程分析

摘要

基于串并联弹簧随机损伤模型,结合损伤模型和断裂模型的耗散能等效原理计算得到了混凝土裂缝黏聚律;基于微弹簧断裂应变服从Weibull分布和对数正态分布,研究了不同概率密度函数对裂缝黏聚律的影响,并比较了所获得的黏聚律与采用位移等效方法获得的黏聚律的区别.依据得到的黏聚律模拟了三点弯曲梁裂缝扩展全过程,结果表明:混凝土裂缝黏聚律受微弹簧断裂应变服从的概率密度函数影响;基于串并联弹簧随机损伤模型得到的裂缝黏聚律基本不受串并联弹簧模型层数影响,避免了获取黏聚律时的模型层数敏感性问题.%Based on the series-parallel spring stochastic damage model,the cohesive laws of concrete were obtained by the method of energy dissipation equivalence between the damage model and the fracture model.The failure strain of the micro-springs in the series-parallel spring model was assumed to be Weibull distribution and lognormal distribution,based on which the effect of different probability density functions on the cohesive laws was studied.The cohesive laws obtained by the present method were compared with those using the traditional displacement equivalence method.The obtained cohesive laws were also used to simulate the full crack propagation process of three-point notched concrete beams.The results show that the cohesive laws can be affected by the probability density functions and the cohesive laws based on the series-parallel spring stochastic damage model are not affected by the layer number of the model,avoiding the sensitivity problem of spring layers.