超高韧性水泥基复合材料动态压缩力学性能的数值模拟研究  

NUMERICAL SIMULATION ON DYNAMIC COMPRESSIVE BEHAVIOR OF ULTRA-HIGH TOUGHNESS CEMENTITIOUS-COMPOSITES

作　　者：徐世烺[1] 陈超[1] 李庆华[1] 赵昕[1] XU Shi-lang;CHEN Chao;LI Qing-hua;ZHAO Xin(Institute of Advanced Engineering Structures and Materials, Zhejiang University, Hangzhou, Zhejiang 310058, China)

机构地区：[1]浙江大学高性能建筑结构与材料研究所

出　　处：《工程力学》2019年第9期50-59,共10页Engineering Mechanics

基　　金：国家自然科学基金项目(51678522);国家自然科学基金优秀青年科学基金项目(51622811)

摘　　要：该文基于HJC本构模型,采用分离式霍普金森杆(SHPB)压杆系统,对掺有聚乙烯醇(PVA)纤维的超高韧性水泥基复合材料(PVA-UHTCC)的动态压缩力学性能进行了数值模拟研究。首先,通过系统分析确定了21项HJC本构参数,并验证了模拟的正确性。基于此,通过分析5组应变率下材料的动态压缩应力-应变曲线讨论了峰值应力动态增强因子DIF的应变率效应,并通过LS-DYNA软件探讨了破坏过程、破坏形态与应变率的关系。模拟结果表明:随着应变率的增加,PVA-UHTCC材料的动态压缩应力-应变曲线呈现由应变硬化主导向着损伤软化主导的转变趋势;此外,PVA-UHTCC峰值应力动态增强因子DIF具有明显的应变率效应,其值随着应变率增加而增加,且在不同应变率区间呈现不同敏感性;通过量化DIF这种分区敏感性,提出了适用于PVA-UHTCC材料的DIF与应变率对数■分段函数式;同时,通过对比钢纤维增强水泥基材料(SFRCC)和普通混凝土材料,发现PVA-UHTCC材料的DIF应变率敏感性较低。最后,通过LS-DYNA软件模拟试件裂缝扩展和压碎破坏过程,更好地理解了PVA-UHTCC材料动态压缩破坏行为。Investigates the dynamic compressive behavior of PVA fiber reinforced ultra-high toughness cementitious-composites(PVA-UHTCC)using Split Hopkinson Pressure Bar(SHPB)test based on HJCconstitutive model.Firstly,21 parameters of HJC model are determined and the numerical simulation is verified.Then dynamic compressive stress-strain curves under 5 different strain rates are obtained for analyzing the strain-rate effects on Dynamic Increase Factor(DIF).The failure modes of specimens under different strain rates are also researched.The results show that with the increase of strain rate,DIF increases and the strain-hardening dominated behavior will transform into a strain-softening dominated behavior.Besides,PVA-UHTCC shows an obvious different strain-rate sensitivity in the different range of strain rates.Thusly,a functional expression between DIF and ■ is proposed.Compared with Steel Fiber Reinforced Cementitious Composites(SFRCC)and normal concrete,PVA-UHTCC has a lower strain-rate sensitivity.Finally,the crack propagation mechanism and failure modes are observed at LS-DYNA software to furtherly understand the dynamic compressive behavior of PVA-UHTCC.

关 键 词：PVA-UHTCC 数值模拟 动态压缩性能 HJC本构模型 SHPB系统 应变率效应 压缩破坏 

分 类 号：TU528.572[建筑科学—建筑技术科学]