用刚体弹簧元法研究全级配混凝土力学性能

提出了采用刚体弹簧元法在细观层次上对全级配混凝土的力学特性及破坏机理进行数值研究的方法.该方法首先根据全级配混凝土骨料级配曲线和Walraven函数,使用蒙特卡罗随机理论建立起考虑细观各相力学特性分布不均匀性的随机骨料结构,并对其进行三角形或任意多边形的网格剖分;然后应用刚体弹簧元模型,对全级配混凝土在单轴及双轴荷载下的变形和力学性能进行了系统性的数值试验,并探讨了不同骨料级配及试件尺寸对混凝土力学性能的影响.与实际试验结果的比较表明运用该方法数值模拟全级配混凝土的力学性能是可行的.

Numerical simulation of mechanical behavior of fully-graded concrete based on rigid body spring model

The mechanical and failure behaviour of fully-graded concrete is analyzed using the mesoscopic approach based on the rigid body-spring element discrete model. First, according to the aggregate grading curve of the fully-graded concrete and Walraven function, a random aggregate structure is generated by the Monte Carlo random sampling principle. In order to reflect the heterogeneity of each phase in concrete at mesoscopic level, the mechanical parameters of these elements in three phases of concrete are assumed to conform to specific normal distribution and a method of mesh generation in which the polygon elements are produced is developed. Then based on the rigid body-spring discrete element model, a procedure for mesoscopic study behaviour of fully-graded concrete under the two-dimensional stress state is presented. At last, the proposed numerical method is validated to simulate some routine tests of concrete carried out in delaboratory and it is proved that this method could effectively describe the failure behaviour of concrete under various plane stress state.