土工格栅蠕变本构模型的UMAT开发与验证

通过不同应力水平下土工格栅的蠕变试验,分析了三种应变类型随应力和时间的变化过程,提出ε=ε(σ,t)形式的土工格栅本构模型,采用有限元程序ABAQUS的用户材料子程序UMAT对本构模型进行了二次开发,并将计算模型的结果与试验数据进行了比较。蠕变试验数据表明在一个受力区间内各种应变随着应力的增加都急剧增长,该区间是进行土工格栅蠕变特性研究的重要区域。计算模型结果表明编程后的能很好地吻合短期蠕变变形试验数据,并能合理预估长期蠕变变形的趋势。完成的土工格栅材料模型可以放入工程结构寿命计算中的材料库,实现土工格栅合理设计的量化分析。

DEVELOPMENT AND VERIFICATION OF THE CREEP CONSTITUTIVE MODEL FOR THE GEOGRID BY UMAT

Through the creep test of the geogrid under different stress levels,three strain types were analysed with stress and time variables.The constitutive model fit for the geogrid was given by the ε=ε(σ,t) form.User-defined material subroutines(UMAT) of ABAQUS was used to implement the constitutive model,whose results were validated by test data.Creep test data show that All of three strain types increase rapidly with the increasing stress in a stress region,which is a important section for the characteristic study of the geogrid creep properties.Results of the computation model indicated programmed UMAT can coincide with the test data of short-term creep deformation and estimate the tendency of long-term creep deformation reasonably.The geogrid material model in the paper can be added to the life calculation material library of engineering structures.quantitative analysis for the rational design of geogrid can be implemented.