基于DIC聚丙烯腈纤维的混凝土断裂性能研究与数值分析  

Study and Numerical Analysis of Fracture Properties ofPolyacrylonitrile Fiber Concrete Based on DIC

作　　者：陈辰 王海龙 曲广雷 李田园 郑木莲[1] CHEN Chen;WANG Hai-long;QU Guang-lei;LI Tian-yuan;ZHENG Mu-lian(Key Laboratory of Special Area Highway Engineering of Ministry of Education,Chang'an University,Xi'an 710064,China;The 7th Engineering Co.,Ltd.,China Railway Major Bridge Engineering Group,Wuhan 430056,China)

机构地区：[1]长安大学特殊地区公路工程教育部重点实验室,西安710064 [2]中铁大桥局第七工程有限公司,武汉430056

出　　处：《科学技术与工程》2024年第34期14796-14805,共10页Science Technology and Engineering

基　　金：国家自然科学基金(52078051);中铁大桥局集团有限公司科技项目(JZDQ-JSFW-28)。

摘　　要：为改善C60混凝土的断裂韧性,探究聚丙烯腈纤维对C60混凝土力学性能的影响规律。在7 d、28 d抗压强度和劈裂抗拉强度的基础上,采用数字图像相关方法进行三点弯曲断裂性能试验。基于双K断裂理论分析了不同聚丙烯腈纤维掺量(0.6、0.9、1.2 kg/m^(3))对C60混凝土起裂韧度和失稳断裂韧度的影响规律。此外,基于扩展有限元法通过Abaqus软件建立了基于能量的线性软化损伤模型,模拟了混凝土梁三点弯曲断裂以及裂缝损伤演化过程。研究结果表明:3种掺量的聚丙烯腈纤维对C60混凝土劈裂抗拉强度均有显著提高趋势,提升幅度分别为33.36%、37.90%、25.28%,而对抗压强度影响并不显著,在掺量较小时抗压强度有小幅提升;基于双K断裂理论,三种纤维掺量对起裂韧度的提升幅度分别为24.23%、70.59%、25.96%,对失稳断裂韧度的提升幅度分别为5.81%、55.93%、13.59%,试验确定聚丙烯腈纤维最佳掺量为0.9 kg/m^(3);聚丙烯腈纤维在混凝土基体开裂过程中逐渐承担荷载,改变了裂缝形貌与演化趋势,使裂缝从主裂缝发展出多条细小裂缝,提高了裂缝发展的复杂程度;通过扩展有限元数值模拟得到的荷载-裂缝张开口位移曲线与试验结果吻合度较高,可以较好地表征聚丙烯腈纤维混凝土的断裂过程和裂缝演化趋势。研究成果为高性能混凝土增强增韧理论、方法与工程应用提供参考和依据。In order to improve the fracture toughness of C60 concrete,the influence law of polyacrylonitrile fiber on the mechanical properties of C60 concrete was investigated.On the basis of 7 d,28 d compressive strength and split tensile strength,the three-point bending fracture performance test was carried out by digital image correlation method.The influence laws of different polyacrylonitrile fiber admixtures(0.6,0.9,1.2 kg/m^(3))on the starting fracture toughness and the destabilized fracture toughness of C60 concrete were analyzed based on the double-K fracture theory.In addition,an energy-based linear softening damage model based on the extended finite element method was established by Abaqus software to simulate the three-point bending fracture of concrete beams and the crack damage evolution process.The results show that:three kinds of polyacrylonitrile fiber dosage on C60 concrete splitting tensile strength have a significant trend of improvement,the enhancement of the magnitude of 33.36%,37.90%,25.28%,respectively,and the impact on compressive strength is not significant,in the dosage of small compressive strength has a small increase.Based on the double K fracture theory,three kinds of fiber dosage on the starting cracking toughness enhancement of 24.23%,70.59%and 70.59%,respectively.24.23%,70.59%,25.96%,and the enhancement of destabilized fracture toughness is 5.81%,55.93%,13.59%,respectively,and the optimum dosage of polyacrylonitrile fibers is determined to be 0.9 kg/m^(3).Polyacrylonitrile fibers gradually assumed the loading during the cracking process of the concrete matrix,which altered the crack morphology and the trend of the cracks,and caused the cracks to develop from the main cracks to a number of the load-crack opening displacement curves obtained by extended finite element numerical simulation are in good agreement with the test results,which can better characterize the fracture process and crack evolution trend of polyacrylonitrile fiber concrete.The research results provide reference and basis

关 键 词：聚丙烯腈纤维 数字图像相关 三点弯曲试验 断裂韧度 扩展有限元 

分 类 号：TU528.572[建筑科学—建筑技术科学]