压剪耦合损伤演化方程在混凝土本构模型中的应用

Application of Damage Evolution Equation Under Coupled Compression-Shear to Constitutive Model of Concrete

将等效微孔洞体系的概念与有核长大模型的思想相结合,根据有关物理关系通过严格的数学推导,提出了一种脆性材料的压剪耦合损伤演化方程.将该演化方程应用于混凝土脆弹性损伤软化本构模型之中,通过对混凝土一维应力条件下的实验应力应变曲线的优化数值模拟确定了损伤演化方程中的材料参数.研究结果表明,应用含损伤的本构关系和该压剪耦合损伤演化方程能得到损伤随时间变化的曲线,该曲线与采用CT技术观测的混凝土内部微孔洞扩展图像和结果有较好的一致性.所提出的损伤演化方程揭示了脆性材料压剪耦合损伤发展的宏细观机制,为更好地分析计算混凝土的高速贯穿等问题奠定了基础.

Combined the concept of equivalent micro voids system with the model of existent damage-nucleation growing up, a damage evolution equation of brittle materials under the coupled compression-shear actions is presented by strict mathematical derivation based on some physical theorems. The parameters in damage evolution equation could be gotten by applying the damage evolution equation to the brittle-elastic damage constitutive model of concrete and simulating result of experimental stress-strain curve. From the damage constitutive relation and the damage evolution equation, the damage-time curve can also be obtained, which is consistent quite well with the pictures of internal micro voids evolution gotten from CT technology. The presented damage evolution equation reveals the macro-microscopic development mechanism of the coupled compression-shear damage in brittle materials. This work establishes a good basis for the computation and analysis of high velocity penetration problems.