低速冲击下钢纤维混凝土梁的动力学行为与三维细观仿真  

Dynamic Behavior and Three-Dimensional Microscopic Simulation of Steel Fiber Reinforced Concrete Beams under Low-Speed Impact

作　　者：张周 马钢[1] 张佳寅 都思哲 常雅坤 李波 ZHANG Zhou;MA Gang;ZHANG Jiayin;DU Sizhe;CHANG Yakun;LI Bo(School of Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学土木工程学院,太原030024

出　　处：《硅酸盐学报》2024年第1期189-202,共14页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(52178239)。

摘　　要：钢纤维的掺入可有效增强混凝土的整体性与基体韧性,满足实际工程中对混凝土材料高强度与高韧性的性能要求,但现阶段对于钢纤维混凝土增强增韧机理与破坏机制的研究主要基于宏观试验,难以全面揭示材料内部损伤破坏过程及钢纤维增韧机理。通过建立钢纤维增强混凝土梁的三维细观模型,更为直观地分析钢纤维掺量和冲击速率对于钢纤维混凝土梁抗冲击性能与破坏形态的影响。结果表明:利用三维钢纤维增强混凝土梁细观模型可有效反映动态冲击条件下梁的力学性能与破坏形式;在低速冲击下,钢纤维的掺入可提升混凝土的耗能与抗冲击性能,且钢纤维存在最优掺量;当冲击速率低于10 m/s时,钢纤维的增强效果更为显著。该成果可为复杂动力环境中或低速冲击威胁下钢纤维混凝土受弯构件的工程应用与安全评估提供参考。Introduction Ordinary concrete rapidly loses its bearing capacity under impact,while the addition of steel fibers effectively enhances the overall integrity and matrix toughness of concrete,thus meeting the concrete performance requirements of high strength,high durability,and high toughness in practical engineering.The existing work on the strengthening and toughening mechanism and failure mechanism of steel fiber reinforced concrete is mainly based on the macroscopic experiments.It is thus difficult to reflect the randomness and non-uniformity of concrete.In this paper,the dynamic response of steel fiber reinforced concrete beam specimens at a low-speed impact was investigated by a drop hammer testing machine to comprehensively reveal the internal damage and failure process of concrete and the toughening mechanism of steel fibers.A three-dimensional microscopic model of steel fiber reinforced concrete beams was proposed,and the mechanical properties and crack development of steel fiber reinforced concrete beams under dynamic impact were analyzed.In addition,the effects of steel fiber volume fraction and impact velocity on the impact resistance and failure morphology of steel fiber reinforced concrete beams were also discussed.Methods Steel fiber reinforced concrete beams with different steel fiber volume fractions(i.e.,0%,0.5%,1.0%,1.5%,2.0%,and2.5%)were prepared based on the experimental mix proportion.The effect of steel fiber volume fraction on the impact performance of steel fiber reinforced concrete beams was analyzed via dynamic three-point bending performance in a model INSTRON-9530 drop hammer impact testing machine.A steel fiber model was randomly proposed based on the Monte Carlo method,and a spring element was used to simulate the bond slip between steel fibers and concrete matrix.Based on its bond slip relationship,a three-dimensional fine calculation model for steel fiber concrete was established.The dynamic response and failure forms of steel fiber concrete were simulated at different volume fract

关 键 词：钢纤维混凝土 细观模型 落锤冲击 抗冲击性能 

分 类 号：TU375.1[建筑科学—结构工程]