基于非均匀性的平台巴西圆盘失效过程及损伤行为  

Failure process and damage behaviour of flattened Brazilian disc specimens based on micro-nonuniformity

作　　者：张亚芳[1] 杨学潮 欧成贵 马兴敏[2] 孔伟[2] ZHANG Yafang;YANG Xuechao;OU Chenggui;MA Xingmin;KONG Wei(School of Civil Engineering and Transportation,Guangzhou University,Guangzhou 510006,Guangdong Province,P.R.China;China Construction Eighth Engineering Division Co.Ltd.,Shanghai 200122,P.R.China)

机构地区：[1]广州大学土木与交通工程学院,广东广州510006 [2]中国建筑第八工程局有限公司,上海200122

出　　处：《深圳大学学报（理工版）》2024年第6期730-738,I0010,共10页Journal of Shenzhen University(Science and Engineering)

基　　金：广东省自然科学基金资助项目(2024A1515011782);国家自然科学基金资助项目(52278250)。

摘　　要：为了探讨冲击荷载作用下裂缝对混凝土失效行为的影响,开展动态冲击荷载下混凝土预制裂缝平台巴西圆盘失效过程及损伤行为的研究.基于分离式霍普金森压杆试验,建立考虑混凝土细观非均匀性的数值模型,根据混凝土预制裂缝分布特征,分析混凝土预制裂缝角度和应变率对次生裂纹扩展规律和损伤演化程度的影响.结果表明,混凝土试件动态抗拉强度与应变率呈显著正相关,而与预制裂缝角度呈负相关.通过对混凝土单元的非均匀赋值,实现了冲击荷载下圆盘试件裂纹的萌生、扩展和贯穿的真实过程,当混凝土预制裂缝倾角大于60°时,主裂纹的扩展方向与预制裂缝近似垂直,次生裂纹数量则随预制裂缝倾角的增大逐渐增多.此外,基于破坏单元个数定量表征试件的损伤程度,发现当预制裂缝倾角为45°时,圆盘试件的损伤程度最低.研究成果可为混凝土材料的动态安全设计提供理论依据.To investigate the effect of cracks on the failure behavior of concrete under impact loading,the failure pro⁃cess and damage behavior of pre-crack flattened Brazilian discs under dynamic impact loading were systematically studied.A numerical model incorporating micro-heterogeneity of concrete was established based on split Hopkinson pressure bar experiments,enabling a quantitative analysis of the influence of different pre-crack inclinations and strain rates on secondary crack propagation and damage evolution,with consideration of the distribution characteris⁃tics of pre-cracks.The results show a significant positive correlation between dynamic tensile strength and strain rate,and a negative correlation of dynamic tensile strength with the inclination of pre-cracks.The model successfully simulated the realistic process of crack initiation,propagation,and penetration within the specimens based on microheterogeneity model.When the pre-crack inclination exceeded 60°,the propagation direction of the main crack was nearly perpendicular to the pre-crack,and the number of secondary cracks increased progressively with the pre-crack inclination.Additionally,by quantifying the damage degree of the specimens through the number of failed elements,it was determined that the damage degree was minimized when the pre-crack inclination was 45°.The research results can provide a theoretical basis for the dynamic safety design of concrete materials.

关 键 词：混凝土 分离式霍普金森压杆 预制裂缝 细观非均匀性 失效过程 损伤行为 

分 类 号：TU528.572[建筑科学—建筑技术科学]