早龄期混凝土单轴拉伸试验的数值模拟

基于强度为C40，龄期分别为2d，7d，28d的混凝土单轴拉伸试验，通过编制用户子程序调用通用有限元软件ABAQUS中的损伤塑性模型，对试验进行了数值模拟。该模型将损伤和塑性作为材料的两个内变量，共同引起混凝土的强度变化及变形。混凝土试件宏观裂缝的出现及扩展（应变软化段）由耦合了损伤变量的弥散裂缝模型进行计算。将模拟出的应力一位移曲线与试验曲线进行对比，并将不同龄期的曲线之间进行了相互对比。结果均令人满意。通过对模拟出的塑性应变场、损伤场的分析，形象地再现了早龄期混凝土试件单轴拉伸破坏的全过程，为早龄期混凝土结构的拉伸损伤断裂过程分析提供了有力的数值工具。

Numerical Simulation for Uniaxial Tension Tests of Young Concrete

Based on the uniaxial tension tests of concrete of C40 at ages of 2d,7d,28d,a finite program ABAQUS is applied to simulate this failure by invoking the concrete damaged plasticity model with user subroutines.This model takes both damage and plasticity as two inner variables,which work together to bring concrete changes at strength and deformation.The smeared cracking model coupling with damage is adopted to calculate the onset and development(strain softening phase) of micro-cracking of concrete specimen.The comparison between the numerical and experimental results shows a good agreement.Meanwhile,comparisons of Stress-Displacement curves for concrete at different ages relatively also show good(agreements.)By analyzing the plastic strain field and the damage field,the uniaxial tension failure of young concrete was visually exhibited,which supplied a powerful numerical tool to the analysis of young concrete tensile failure.