定向钢纤维增强水泥基复合材料断裂特性模拟分析

利用钢纤维随机生成算法建立了钢纤维增强水泥基复合材料有限元模型,基于粘聚裂纹模型模拟了定向钢纤维水泥砂浆三点弯曲断裂全过程.将数值模拟得到的荷载-绕度曲线与已有试验结果进行对比,验证了数值模型的可靠性.研究了砂浆基体不同粘聚律对定向钢纤维水泥砂浆断裂全过程的影响.计算分析了不同尺寸试件模型的断裂全过程,研究了试件尺寸对定向钢纤维水泥砂浆断裂特性的影响.结果表明:本文建立的定向钢纤维水泥砂浆有限元模型的数值结果与试验结果对比较好,粘聚律的变化对断裂全曲线影响较小;随着试件尺寸的增大,定向钢纤维水泥砂浆的名义强度存在一定的尺寸效应,本文建立的细观模型可有效研究钢纤维增强水泥基复合材料的细观断裂机理.

Simulation Analysis of Fracture Characteristics for Aligned Steel Fiber Reinforced Cementitious Composites

The finite element model of steel fiber reinforced cementitious composites was established based on random generation algorithm,simulated whole process of bend fracture for a three-point bend Aligned Steel Fiber Reinforced Cementitious Composites(ASFRC)beam using cohesive crack model.The reliability of the numerical model was verified by comparing load-deflection curve of numerical simulation and existing experimental results.The effects of different cohesive-law of matrix on the whole fracture process for ASFRC were investigated.And the whole fracture process of specimens with different sizes was simulated and analyzed.The influence of specimen's size on the fracture behavior of ASFRC was studied.The results show that in this study,simulated results of finite element model for ASFRC matched well with experimental results, the types of cohesive-law have little influence on the fracture complete curves;with the increase of specimen's size,the nominal strength of ASFRC has a obvious size effect, the meso-scale numerical model can effectively study the meso-scale failure mechanism.