摘要
研究了中国Q690高强度结构钢在不同低应变率下的真实应力-应变关系和延性断裂特征。加载了3种不同开口尺寸的单轴拉伸平板试件和纯剪试件,获得了广泛的应力状态。用试验结合数值模拟的方法确定等效塑性断裂应变、应力三轴度和罗德参数。结果表明,应力三轴度和罗德参数是控制断裂的主要影响因素。与应力相比,应变对应变率更为敏感,等效塑性断裂应变随应变率的增大而增大。此外,由于断裂前纯剪试件标距范围发生明显的变形和应力集中现象,断裂面以拉应力或拉剪应力为主,纯剪试件的设计需要进一步研究。
The true stress-strain relationship and ductile fracture characteristics of Chinese Q690 high strength structural steel were investigated at different low strain rates.Sheet Q690 specimens with one unnotched and two different notch geometries were used for uniaxial tensile tests,and pure shear sheet specimens were also used for shear tests.These specimens were loaded to obtain a wide range of stress states.A hybrid experiment-simulation approach was used to determine the equivalent plastic strain to fracture,the stress triaxiality and the Lode parameter.The results showed that the stress triaxiality and the Lode parameter are the key factors controlling fracture,and that the strain is more sensitive to strain rate as compared to stress.It was observed that the equivalent plastic fracture strain increases with increasing strain rate.Further studies are required to design pure shear specimens since it is difficult to realize pure shear stress state on the fracture sections in most of the pure shear tests due to the obvious deformation and stress concentration before a fracture occurs at the gauge area.
作者
董俊宏
沙佳阿里阿里
杨波
丁浩敏
DONG Junhong;SHAGEA Ali Ali;YANG Bo;DING Haomin(School of Civil Engineering,Chongqing University,Chongqing 400045,P.R.China)
出处
《土木与环境工程学报（中英文）》
CSCD
北大核心
2021年第1期72-81,共10页
Journal of Civil and Environmental Engineering
基金
National Natural Science Foundation of China(No.51778086)。
关键词
高强度结构钢
延性断裂
应力三轴度
罗德参数
应变率
high strength structural steel
ductile fracture
stress triaxiality
Lode parameter
strain rate
