摘要
在混凝土静态破坏尺寸效应方面已取得了较完善的成果,而在动态破坏尺寸效应方面,包括其产生机制及对应的尺寸效应律的研究则非常匮乏。为探讨动态荷载作用下混凝土尺寸效应行为,从细观角度出发,结合混凝土细观结构特征,考虑动态加载下细观组分应变率效应的影响,建立了混凝土破坏行为研究的细观力学分析模型与方法。以双边缺口混凝土试件为例,对其在低应变率(10^-5 s^-1~1 s^-1)下混凝土动态拉伸破坏行为及尺寸效应进行细观数值模拟,并分析了应变率效应对动态破坏尺寸效应的影响。最后,结合应变率效应对强度及尺寸效应的影响规律—“强度增强效应”与“尺寸效应削弱效应”,在静态破坏尺寸效应律的基础上,建立了混凝土拉伸强度的“静动态统一”尺寸效应理论公式,并验证了理论公式的准确性和合理性。
Great progresses have been made in static size effect of concretes,while few efforts have been conducted in dynamic size effect of concretes.Herein the study,in order to explore the size effect of concrete under dynamic loadings,considering concrete heterogeneities and the strain rate effect for the meso components,a meso-scale simulation method was built.Taking the double notched concrete specimens as examples,the dynamic tensile failure and the size effect of concrete under low strain rates from 10^-5 s^-1 to 1 s^-1 were investigated using the meso-scale simulation method.The effect of strain rate on the size effect in tensile strength of concrete was also analyzed.Finally,based on the influencing mechanism of strain rate effect on dynamic strength and size effect,i.e.the enhancement of strength and weakening of size effect,a“static-dynamic unified size effect law”for dynamic tensile strength of concrete was established.The proposed size effect law was also calibrated by meso-scale simulation results.
作者
金浏
余文轩
杜修力
张帅
李冬
JIN Liu;YU Wen-xuan;DU Xiu-li;ZHANG Shuai;LI Dong(Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China;Department of Civil Engineering,Tsinghua University,Beijing 100084,China)
出处
《工程力学》
EI
CSCD
北大核心
2019年第8期59-69,78,共12页
Engineering Mechanics
基金
国家重点研发计划项目(2018YFC1504302,2016YFC0701100)
国家自然科学基金项目(51822801,51421005)
关键词
混凝土
动态拉伸
临界应变率
尺寸效应
细观模拟
尺寸效应律
concrete
dynamic tension
critical strain rate
size effect
meso-scale simulation
size effect law