基于弥散旋转裂缝理论的UHP-FRC三维材料模型

Research on UHP-FRC Three-dimensional Materials Model Based on Smeared Rotating Crack Theory

基于Rots弥散裂缝理论以及旋转裂缝理论,在有限元软件LS-DYNA的UMAT自定义界面采用FORTRAN语言建立UHP-FRC的三维本构材料模型,该模型可以反映材料在拉伸荷载作用下的应变强化现象,而且在复杂的微小开裂过程中裂缝平面可以随主应力方向的变化而旋转。利用该本构模型对UHP-FRC材料的直接拉伸试验和标准梁弯曲试验进行数值模拟,模拟得到的应力-应变曲线以及荷载-挠度曲线与实验结果呈良好的一致性,表明所建立的模型可以较为合理地模拟UHP-FRC在拉伸荷载作用下的本构行为。

Based on the Rots diffusion fracture theory and Rotation fracture theorY, a three-dimensional constitutive material model for the finite element simulation of UHP-FRC is established in the finite element software LS-DYNA by using FORTRAN and the user-defined material model interface. The proposed model considers the special strain hardening period, and the normal directions of the crack planes are coincidee with the principle stress directions during the multiple narrow cracking process. The performance of the proposed model is demonstrated by a direct tensile test as well as a bending test of a standardized beam. The simulated stress-strain curve and load-deflection curve are in good agreement with the experimental results, which suggest that the developed model can reasonably simulate the constitutive behavior of UHP-FRC under tensile loading.