【摘要】 混凝土损伤断裂过程伴随着能量耗散过程或不可逆的热力学过程,断裂和损伤实际上是一交织发展的耦合过程。本文主要针对I型张开型裂纹进行研究,参照双G模型理论和损伤能量释放率的概念,推导出裂纹尖端邻域内损伤场与断裂场的耦合参数、损伤型的能量释放率。应用虚拟裂纹闭合法对一组三点弯曲梁进行数值模拟,说明了该参数可以用来描述裂纹邻域内的物理场,以此代替无损材料中能量释放率的概念。将其与加载过程中能量释放率G、损伤能量释放率Y随缝长变化的规律作比较,给出裂纹失稳时对应的损伤型能量释放率,并说明损伤型的能量释放率可以合理地描述裂纹前沿邻域内损伤断裂的耦合场。更多还原

【Abstract】 Damage and fracture processes of concrete are attended with energe dissipation or nonreversible thermodynamics process.Essence of damage and fracture is a interlaced coupling process.In view of I-type crack and beased on dual G model theory and damage energy release rate concept,this paper deduces coupling parameters between damage field and fracture field for tip region of crack,i.e.damage type′s energy release rate.The virtual crack closure technique(VCCT) was used for numerical simulation of a set of three-point bending beam.Results show that this parameter can be used to discribe the physical field in crack neighborbood instead of concept of energy release rate in non-loss material.Comparing it with the regulation regarding change of energy release rate G and damage energy release rate Y with crack length,the damage-type energy release rate corresponding to instability of crack was presented and it is explained that damage-type energy release rate can describe coupling field of damage fracture in tip region of crack reasonably.更多还原