【作者】 张向荣；

【导师】 张淳源；

【作者基本信息】 湘潭大学 ， 一般力学与力学基础， 2002， 硕士

【摘要】 混凝土是一由粗骨料和硬化水泥沙浆组成的多相复合材料。在粗骨料和硬化水泥沙浆之间有许多微裂纹。在载荷作用下，微裂纹的数量增加，扩展最后变成宏观裂纹，从而导致结构的破坏。 研究者们已经认同了混凝土材料的连续损伤。混凝土也同样是一种时间相依性质的材料。徐变就是它的时间效应之一。对于计算力学来说，本构关系的求出是很重要的。在混凝土的非线性粘弹性方面的研究工作目前还不多见。随着计算机技术的发展，考虑混凝土非线性粘弹性的本构关系不仅在理论上有价值，在实际的应用上也有现实意义。 本文结合弹性回复对应原理 ，从非线性粘弹性材料的连续介质热力学分析入手，通过不可逆热力学定律来求出含损伤的非线性粘弹性本构关系。针对不同应变率下的单轴压缩实验，分别应用考虑损伤和不考虑损伤的本构关系进行力学模拟，发现应变率比较大的时候，混凝土材料可以不考虑损伤；当应变率比较小的时候，混凝土材料要考虑损伤，。弹性回复对应原理可以推广应用于混凝土材料，从而为研究混凝土材料的粘弹性问题提出了一个新的研究方法。更多还原

【Abstract】 Concrete is the composite multiphase material made up of stones and ossified cement grout. There are many micro-cracks between the stones and the ossified cement grout. Under load, the number of the micro-cracks increases; the micro-cracks expand and eventually become macro-cracks, which result in the failure of the structure. The continuous damage in concrete is recognized by researchers. Concrete is also a time-dependant material. Creep is one of its time-dependent properties. The constitutive relation is very important for the computational mechanics. There are not many research jobs on the concrete nonlinear viscoelastic relations, and the damage is not considered in many jobs. With the development of the computer skill, to develop concrete nonlinear viscoelastic constitutive relation is not only reasonable but also realistic. In this paper, using the elasticity recovery correspondence principle and the nonlinear viscoelastic continuum thermodynamics, we utilize the irreversible thermodynamics to get the nonlinear viscoelastic relations with damage.In the end, we use the constitutive relations with damage and these without damage to analyze the uni-axial concrete compression experiment under different constant strain-rates, so it is validated by mechanical simulation. We find that when the strain-rate is low, we should use the constitutive relations with damage to predict; when the strain-rate is high, we should use the constitutive relations without damage to predict. The elastic recovery correspondence principle can be applied to analyze the concrete, which makes a new research method for the concrete nonlinear viscoelastic problem.更多还原