纤维混凝土的损伤力学模型及抗拉性能研究
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摘要
数值模拟方法广泛应用于纤维混凝土抗拉性能的研究中,但是由于纤维的尺寸较小且数量庞大,使得常用的等效模拟方法和离散模拟方法在模拟精度或建模效率上难以兼顾。近年提出的半离散模拟方法克服了上述方法在纤维几何模拟上的缺陷,实现了精度和效率的平衡,但是该方法在力学模型方面仍有改进的空间。通过借鉴混凝土的多线性损伤理论,构建了纤维强弱黏结损伤力学模型,与混凝土损伤力学模型相结合,实现了纤维混凝土损伤力学模型的统一,并据此改进了半离散模拟方法,这有利于该方法在纤维混凝土力学特性研究中的应用。基于上述理论,使用FORTRAN语言编写了相应的程序。针对单骨料混凝土试件的单轴拉伸试验以及砂浆试件的单丝拉拔试验,通过数值试验与物理试验的结果对比,验证了纤维混凝土损伤力学模型的合理性。基于骨料级配曲线以及蒙特卡洛方法,生成了一组复杂纤维混凝土试件,通过一系列单轴拉伸数值试验,研究了不同纤维掺量、纤维初始刚度、砂浆强度对混凝土抗拉强度、阻裂性能及韧性的影响。
Numerical simulation methods are widely used to study the tensile properties of fiber reinforced concrete,including equivalent approach and discrete approach. However,due to the small size and large number of fibers,these methods can hardly keep a balance between accuracy and efficiency in modeling fibers. The semi-discrete approach has been proposed in recent years to deal with the problem of fiber modeling,but it still needs a better constitutive model to describe the mechanical behavior of fibers. Through studying the multi-linear damage theory of concrete,a damage model is proposed for the fibers connected with concrete strongly or weakly. The damage models of both concrete and fibers are realized in a unified form. The unified damage model is embedded into the semi-discrete approach,and the relevant program is coded by FORTRAN. The improved semi-discrete approach can benefit the study of fiber reinforced concrete. Based on a uniaxial tensile test with a single aggregate concrete specimen and a single fiber pull-out test with a mortar specimen,the results of numerical test and physical test are compared to validate the unified damage model. By using the aggregate grading curve and the Monte Carlo method,a reinforced concrete specimen is generated with the complex distribution of fibers and aggregates. Through a series of uniaxial tensile numerical tests,the tensile strength,crack resistance and ductility of fiber reinforced concrete are studied under the effects of fiber content,fiber stiffness and mortar strength.
Numerical simulation methods are widely used to study the tensile properties of fiber reinforced concrete,including equivalent approach and discrete approach. However,due to the small size and large number of fibers,these methods can hardly keep a balance between accuracy and efficiency in modeling fibers. The semi-discrete approach has been proposed in recent years to deal with the problem of fiber modeling,but it still needs a better constitutive model to describe the mechanical behavior of fibers. Through studying the multi-linear damage theory of concrete,a damage model is proposed for the fibers connected with concrete strongly or weakly. The damage models of both concrete and fibers are realized in a unified form. The unified damage model is embedded into the semi-discrete approach,and the relevant program is coded by FORTRAN. The improved semi-discrete approach can benefit the study of fiber reinforced concrete. Based on a uniaxial tensile test with a single aggregate concrete specimen and a single fiber pull-out test with a mortar specimen,the results of numerical test and physical test are compared to validate the unified damage model. By using the aggregate grading curve and the Monte Carlo method,a reinforced concrete specimen is generated with the complex distribution of fibers and aggregates. Through a series of uniaxial tensile numerical tests,the tensile strength,crack resistance and ductility of fiber reinforced concrete are studied under the effects of fiber content,fiber stiffness and mortar strength.
引文
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[15]赵树青.碳纤维棒与聚合物砂浆复合材料受力性能研究[J].低温建筑技术,2018,40(10):27-29,47.
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[17]CORR D,ACCARDI M,GRAHAM-BRADY L,et al.Digital image correlation analysis of interfacial debonding properties and fracture behavior in concrete[J].Engineering Fracture Mechanics,2007,74(1-2):109-121.
[18]邓宗才,李建辉,傅智,等.聚丙烯纤维混凝土直接拉伸性能的试验研究[J].公路交通科技,2005(7):45-48.
[19]BANTHIA N,MONCEF A,Chokri K,et al.Uniaxial tensile response of microfibre reinforced cement composites[J].Materials and Structures,1995,28(9):507-517.
[20]李光伟,鲁少林,钟贻辉.PVA纤维在水工高拱坝混凝土中的应用[J].华北水利水电学院学报,2012,33(6):112-115.
[21]YANG Meng,HUANG Chengkui,WANG Jizhong.Characteristics of stress-strain curve of high strength steel fiber reinforced concrete under uniaxial tension[J].Journal of Wuhan University of TechnologyMater.Sci.Ed.2006,21(3):132-137.
[2]陈娴,孟云芳.纳米碳纤维混凝土力学性能试验研究[J].中国农村水利水电,2014(7):126-129,135.
[3]苑坤兴.聚丙烯纤维混凝土力学性能及细观结构的数值模拟[D].山东青岛:中国石油大学,2011.
[4]薛兵.基于细观尺度的钢纤维混凝土损伤破坏数值模拟研究[D].江苏徐州:中国矿业大学,2017.
[5]张巨功.短纤维增强混凝土破坏过程及其尺寸效应数值模拟[J].公路工程,2015,40(2):87-91.
[6]RADTKE F K F,SIMONE A,SLUYS L J.A computational model for failure analysis of fibre reinforced concrete with discrete treatment of fibres[J].Engineering Fracture Mechanics,2010,77(4):597-620.
[7]NAAMAN A E,NAMUR G G,ALWAN J M,et al.Fiber pullout and bond slip.I:Analytical study[J].Journal of Structural Engineering,1991,117(9):2 769-2 790.
[8]RRDTKE F K F,SIMONE A,SLUYS L J.A computational model for failure analysis of fibre reinforced concrete with discrete treatment of fibres[J].Engineering Fracture Mechanics,2010,77(4):597-620.
[9]BARNES B D,DIAMOND S,DOLCH W L.Micromorphology of the interfacial zone around aggregates in Portland cement mortar[J].Journal of the American Ceramic Society,1979,62(1-2):21-24.
[10]LI W,XIAO J,SUN Z,et al.Interfacial transition zones in recycled aggregate concrete with different mixing approaches[J].Construction and Building Materials,2012,35:1 045-1 055.
[11]LI Shuguang,LI Qingbin.Method of meshing ITZ structure in 3Dmeso-level finite element analysis for concrete[J].Finite Elements in Analysis and Design,2015,93:96-106.
[12]马怀发,陈厚群,阳昌陆.复杂动荷载作用下全级配混凝土损伤机理细观数值试验[J].土木工程学报,2012,45(7):175-182.
[13]王成.单向钢纤维增强水泥砂浆的各向异性研究[D].天津:河北工业大学,2015.
[14]任慧韬.纤维增强复合材料加固混凝土结构基本力学性能和长期受力性能研究[D].辽宁大连:大连理工大学,2003.
[15]赵树青.碳纤维棒与聚合物砂浆复合材料受力性能研究[J].低温建筑技术,2018,40(10):27-29,47.
[16]ABRISHAMBAF A,CUNHA V M C F,BARROS J A O.A twophase material approach to model steel fibre reinforced self-compacting concrete in panels[J].Engineering Fracture Mechanics,2016,162:1-20.
[17]CORR D,ACCARDI M,GRAHAM-BRADY L,et al.Digital image correlation analysis of interfacial debonding properties and fracture behavior in concrete[J].Engineering Fracture Mechanics,2007,74(1-2):109-121.
[18]邓宗才,李建辉,傅智,等.聚丙烯纤维混凝土直接拉伸性能的试验研究[J].公路交通科技,2005(7):45-48.
[19]BANTHIA N,MONCEF A,Chokri K,et al.Uniaxial tensile response of microfibre reinforced cement composites[J].Materials and Structures,1995,28(9):507-517.
[20]李光伟,鲁少林,钟贻辉.PVA纤维在水工高拱坝混凝土中的应用[J].华北水利水电学院学报,2012,33(6):112-115.
[21]YANG Meng,HUANG Chengkui,WANG Jizhong.Characteristics of stress-strain curve of high strength steel fiber reinforced concrete under uniaxial tension[J].Journal of Wuhan University of TechnologyMater.Sci.Ed.2006,21(3):132-137.