摘要
从试件边界条件对断裂过程区的影响出发,研究了断裂特性在韧带上的分布特征,解释了根据断裂功原理测试得到的断裂能的尺寸效应现象。并以此为基础,通过引入局部断裂能的概念,推导出与尺寸无关的混凝土断裂能表达式。以不同韧带长度的楔入劈拉和三点弯曲梁试验进行了验证工作。结果表明,在试件的破坏状态,由于边界条件的限制,局部断裂能在韧带方向上的分布是不均匀的,从而引起测试断裂能的尺寸相关性。根据建立的模型计算得出的断裂能与试件尺寸无关,但反映边界影响的长度参数却随着试件尺寸的变化而变化。
Fracture properties along ligament length are investigated by considering the influence of specimen boundary condition. An explanation is presented for the specimen size effect on specific fracture energy observed in experiments. Based on the explanation, a model for size-independent fracture energy is provided by introducing a concept of local fracture energy. Wedge splitting tests and experimental results from three-point bending tests available in literature were used to verify the proposed model. It is shown that the local fracture energy spread in a non-uniform manner along the ligament length when the specimen failed, which led to the size-dependence of the traditional fracture energy. Furthermore, the computed value of the proposed fracture energy was kept approximately constant irrespective of the specimen size. The parameter reflecting the boundary influence, however, was size dependent.
出处
《工程力学》
EI
CSCD
北大核心
2007年第1期56-61,共6页
Engineering Mechanics
基金
国家973项目(2002CB412709)
国家自然科学基金重点项目(50438010)
关键词
混凝土
断裂能
尺寸效应
断裂过程区
局部断裂能
concrete
fracture energy
size effect
fracture process zone
local fracture energy
