摘要
双G断裂模型是双K断裂模型的延伸和补充。采用改进的圆形紧凑拉伸法进行试验,首先验证这种新型断裂力学试验方法能否获得稳定的双G断裂参数,并将公式K=(EG)^(1/2)得到的双K断裂韧度与直接计算得到的结果相比较,进一步验证双G断裂模型和双K断裂模型在描述断裂性能方面的等效性。同时研究了两种断裂模型参数的尺寸效应。试验试件直径从150 mm到300 mm变化,共计分为4组。试验结果表明,采用改进的圆形紧凑拉伸法测得双G参数的数值较为稳定,离散性较小。双G断裂模型和双K断裂模型在描述断裂性能方面具有很高的等效性。在本文的尺寸范围内,当试件直径大于200 mm时,起裂断裂参数KiniIc和GiniIc没有明显的尺寸效应,失稳断裂参数K_(Ic)^(un)和G_(Ic)^(un)随着试件尺寸的增大而增大,但增长幅度不大。
The double-G fracture model is an extension and supplement of the double-K fracture model.The modified round compact tension method were used to verify whether the new fracture mechanics testmethod can obtain stable double-G fracture parameters. The double-K fracture toughness calculated by the formula K = EG was compared with the direct calculation results, in order to further verify the equiva-lence between the double-G fracture model and the double-K fracture model in describing fracture perfor-mance. At the same time,the size effect of two fracture models was studied. The diameters of the 16 testspecimens varied from 150 mm to 300 mm,which were divided into 4 groups. The experimental results showthat the value of the double-G parameters measured by the modified round compact tension method ismore stable and the dispersion is smaller. The double-G fracture model and the double-K fracture modelhave high equivalence in describing the fracture properties. When the specimen diameter is greater than200 mm,initial fracture toughness KiniIcand initial energy release rate GiniIchave no obvious size effect,unstable fracture toughness KunIcand unstable energy release rate GunIcincreases with the specimen size increasing,but the growth is small.
作者
李庆华
种法澄
张麒
徐世烺
LI Qinghua;CHONG Facheng;ZHANG Qi;XU Shilang(Institute of Advanced Engineering Structures and Materials, Zhejiang University, Hangzhou 310058, China)
出处
《水利学报》
EI
CSCD
北大核心
2018年第4期474-482,共9页
Journal of Hydraulic Engineering
基金
浙江省自然科学基金项目(LR16E080001)
国家自然科学基金项目(51378461)
关键词
双K断裂模型
双G断裂参数
能量法
改进的圆形紧凑拉伸试件
double-K fracture model
double-G fracture parameters
energy release rate
modified round compact tension specimen
