Constitutive Model and Mechanical Properties of Steel Fiber Reinforced Concrete

DOI：

 作者 单位 毕继红1，2?覮，霍琳颖1，赵云1，王照耀1 （1. 天津大学 建筑工程学院，天津 300350；2． 滨海土木工程结构与安全教育部重点实验室，天津 300072）

为充分研究钢纤维混凝土的力学性能，基于混凝土的弥散开裂模型，并考虑纤维与混凝土之间的黏结作用，建立了新的钢纤维混凝土本构模型. 在模型中分两种情况考虑纤维作用，混凝土开裂前，纤维与混凝土完全黏结，服从复合材料理论；混凝土开裂后，将分别考虑混凝土和钢纤维的贡献. 通过黏结滑移模型，计算钢纤维在混凝土中脱黏和拔出过程中，纤维对开裂后混凝土的增强作用. 采用Fortran编程，利用有限元软件ABAQUS中提供的子程序Umat，将提出的本构模型引入ABAQUS，并用于有限元模型去模拟钢纤维混凝土的拉伸和四点弯曲试验. 通过数值模拟结果和试验数据的对比，充分验证了所提出的钢纤维混凝土本构模型的准确性. 并对钢纤维混凝土的受拉强度、残余强度、受弯强度以及韧性等力学性能进行详细的分析.

In order to study the mechanical properties of steel fiber reinforced concrete（SFRC），a new constitutive model of SFRC is established in this paper based on the smeared crack model of the plain concrete and considering the bonding effect between fiber and concrete. In this model，the reinforcement of the steel fiber is considered in two cases. Before the cracking，the steel fiber and concrete matrix are fully bonded，which meets the two-phase composite law. When the concrete crack initiates and propagates，the contribution of the concrete and the steel fiber is considered separately. And the strengthening effect of fiber on the concrete cracked plane is considered through the bond-slip model during the process of fiber partially debonded and fully debonded from the concrete matrix. Through Fortran programming，the proposed constitutive model is introduced into ABAQUS software by using the subroutine Umat，and the finite element model is established to simulate the tensile tests and 4-points flexural tests of SFRC. Though the comparison of numerical simulation results and available experimental data，the accuracy of the constitutive model is verified. Meanwhile，the mechanical properties of SFRC including tensile strength，residual strength，flexural strength，and toughness are analyzed in detail.