钢纤维增强砂浆的轴拉损伤力学模型

基于Li Fa Ming的平行棒模型,对短钢纤维增强砂浆的平板试件,在直接拉伸条件下的破坏行为进行了分析,假设试件由N根相互平行的复合棒组成,每根复合棒又由一根纤维棒和S根砂浆棒组成,考虑纤维在基体中分布的方向因子和长度因子.砂浆的损伤可按连续损伤力学进行处理,将Loland模型和Mazars模型加以改进来描述.依据多根纤维的拉拨模型,假定纤维与基体间界面的损伤由纤维脱粘长度与纤维插入长度的比值来描述,复合材料的损伤包括基体的损伤和纤维的损伤,借助已有的试验数据和文献资料来确定本构模型中的各种参数,成功建立了短钢纤维增强砂浆直接拉伸应力一应变全曲线模型.所建模型与试件在直接拉伸试验下的应力-应变全曲线进行了对比,结果较为吻合.

Direct tensile damage mechanic model of steel fiber-reinforced mortar

Based on Li Fa Ming's parallel bar model,one plane specimen composed of mortar and short steel fibers is analyzed in direct tension.A new damage model is attained,which assumed that the specimen is consisted of N composite bars,Each composite bar contains S mortar bars and one fiber bar..Considering the effect of fiber length and orientation,mortar damage is based on continuum damage mechanics,Loland model and Mazars model are introduced,but some modifications are made to accommodate the present study.In terms of huang's multi-fiber pullout model that assumed one fiber's failure will affect the other fibers around itself,interfacial damage between mortar matrix and fiber can be depicted by a ratio value of interfacial debonding length and fiber embedded length.Complex material damage contains mortar damage and fiber interfacial damage,some parameters of constitutive model depends on experimental data and references,so damage constitutive equation of steel fiber-reinforced mortar in direct tension can be obtained.A good agreement between the model predicted stress-strain whole curve and the experimentally obtained one shows that the analytical model is very successful.