摘要
为研究超高性能混凝土(ultra-high performance concrete, UHPC)在高温-爆炸冲击耦合作用下的动态力学特性,采用高温分离式霍普金森压杆(split Hopkinson pressure bar, SHPB)实验系统,开展了25~600℃温度及90~200 s^(-1)应变率范围内C140 UHPC单轴压缩实验,系统分析了高温与冲击耦合作用下材料的强度、应变、韧性、应力-应变关系及破坏形态,揭示了温度与应变率效应对其动态力学性能的影响规律,并基于温度效应修正了Holmquist-Johnson-Cook(HJC)本构模型屈服面。结果表明:UHPC在高温动态压缩下表现出显著的应变率强化效应,但高温同时劣化其力学性能;材料应变能力与韧性演化规律源于温度效应与应变率效应的协同作用;在相同温度下,提高应变率可加剧UHPC的破坏程度。当温度超过400℃时,UHPC基体劣化及钢纤维氧化致使材料整体呈现脆性破坏特征,然而其局部芯部仍保持完整并具有显著残余承载能力;修正后的HJC屈服面适用于该类材料在高温与冲击耦合作用下的动态力学性能研究。
In order to investigate the dynamic mechanical properties of ultra-high performance concrete(UHPC)under coupled high-temperature and explosive impact effects,a 75 mm-diameter high-temperature split Hopkinson pressure bar(SHPB)apparatus was employed.Uniaxial compression tests were conducted on C140 UHPC specimens in the temperatures ranging from 25℃to 600℃and the strain rate ranging from 90 s^(-1) to 200 s^(-1).A systematic analysis was performed on the strength,strain,toughness,stress-strain relationship,and failure modes of the material under the combined condition of high temperature and impact loading.The influence of temperature and strain rate on the dynamic mechanical properties was revealed,and the yield surface of the Holmquist-Johnson-Cook(HJC)constitutive model was modified by incorporating thermal effects.The results indicate that UHPC exhibits a significant strain rate strengthening effect under high-temperature dynamic compression,while elevated temperatures simultaneously degrade its mechanical properties.The evolution of material strain capacity and toughness stems from the synergistic interaction between thermal and strain rate effects.At identical temperatures,increased strain rates exacerbate the damage of UHPC.When temperatures exceed 400℃,matrix degradation and steel fiber oxidation cause the material to exhibit overall brittle failure characteristics;however,its local core region remains integrity and retains notable residual load-bearing capacity.The modified HJC yield surface is suitable for describing the dynamic mechanical behavior of this material under coupled high-temperature and impact conditions.These findings provide theoretical foundations and data support for the safety design and evaluation of military and civil protective engineering.
作者
张臣
高飞
何睿
王振
张国凯
ZHANG Chen;GAO Fei;HE Rui;WANG Zhen;ZHANG Guokai(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China;School of Safety Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu,China)
出处
《爆炸与冲击》
北大核心
2026年第2期107-123,共17页
Explosion and Shock Waves
基金
国家自然科学基金(12002171)
中央高校基本科研业务费专项资金(30925010503)。
关键词
超高性能混凝土
高温分离式霍普金森压杆(SHPB)实验
温度效应
应变率效应
动态力学性能
ultra-high performance concrete
high-temperature split Hopkinson pressure bar(SHPB)experiment
temperature effect
strain rate effect
dynamic mechanical properties
