钢纤维混凝土细观建模方法及力学特性研究

Study on mesoscopic modeling method and mechanicalproperties of steel fiber reinforced concrete

钢纤维混凝土内部缺陷的萌生、扩展等变化过程,需从细观角度出发进行研究。为了建立更加接近实际的钢纤维混凝土细观随机分布模型,提出了一种高效可靠的钢纤维混凝土细观建模方法。采用Python语言对ABAQUS程序进行二次开发,避免了建模中不同软件之间信息传递过程繁琐的问题。提出了一种新的关于多边形骨料和钢纤维的干涉判断方法——点线法,推导了在任意椭圆形骨料边界上取点的方程,提高了骨料投放的高效性。基于上述方法,对钢纤维混凝土试件在单轴压缩下的破坏过程进行了模拟并与试验结果进行对比。结果表明:对于二维细观模型中的二级配多边形骨料投放比可以达到70%,椭圆形骨料投放比可以达到69%;消除了钢纤维在建模过程中相交的现象。数值模拟得到的破坏形态和应力-应变曲线与试验得到的吻合较好,进一步验证了提出的方法可行性。

The changing process of internal defects of steel fiber reinforced concrete,such as initiation and expansion,needs to be studied from a mesoscopic perspective.In order to establish a more realistic mesoscopic random distribution model of steel fiber reinforced concrete,an efficient and reliable mesoscopic modeling method of steel fiber reinforced concrete is proposed.The secondary development of the ABAQUS program is carried out in Python language,which avoids the tedious problem of the information transfer process between different software in modeling.A new interference judgment method for polygon aggregate and steel fiber is proposed—point line method,and the equation of taking points on the boundary of arbitrary elliptical aggregate is derived,which improves the efficiency of aggregate delivery.Based on the above method,the failure process of steel fiber concrete specimen under uniaxial compression is simulated and compared with the test results.The results show that the delivery ratio of second graded polygon aggregate is 70%,the delivery ratio of second graded elliptical aggregate is 69%in 2D mesoscopic model and the intersection of steel fiber in modeling process is eliminated.The failure patterns and stress-strain curves obtained by numerical simulation are in good agreement with the experimental results.The feasibility of the proposed method is further verified.