为从细观结构上研究混凝土劈裂抗拉强度 ,通过 自编程序建立混凝土细观模型,采用混凝土 损伤塑性模型描述细观各相材料的损伤演化。利用有限元技术数值模拟三级配混凝土试件的细观损伤 断裂和劈裂抗拉 强度 ,探讨 了不 同骨料分布、骨料形状、垫条 宽度及界面厚度对劈 裂抗拉强度的影 响。结果表明:不同骨料分布和骨料形状对劈拉极限强度略有影响 ,但数值模拟结果均在试验统计范 围内,且与文献资料 中给定的试验结果相符。按照现行试验规程选取垫条宽度时,可以有效地缓解加 载部位应力集中现 象,使劈拉强度接近真实混凝土强度。骨料粘结界面厚度越小,混凝土劈拉极限强 度越 高。 关键 词 :混 凝 土 ;损 伤 塑性模 型 ;劈拉 强度 ;数 值模 拟 doi:10.13928/j.cnki.wrahe.2015.12.026 中图分类号 :TU528.1 文献标识码 :B 文章 编号 :1000—0860(2015)12—0109—05 2——D m esoscopicnum ericalsimulation on splitting tensile strength ofthree-graded concrete W U Liang, BO Changhuai, YU Haiying, MEIKaihua (FacultyofElectricPowerEngineering,KunmingUniversityofScienceandTechnology,Kunming 650500,Yunnan,China) Abstract:In ordertostudythesplittingtensilestrengthofconcretefrom themeso—structure,thedamageevolutionsofalltheme— soscopicphasesofthematerial aredescribedwiththeconcretedamage—plasticitymodelthroughtheconcretemesoscopicmodeles— tablishedbyself-programming.Themeso·damagefractureand splittingtensilestrengthofthethree—gradedconcretespecimenare numerically simulatedwiththefiniteelementtechniqueforresearchingtheimpactsfrom variousaggregatedistributions,aggregate shapes,spacerwidthsandthicknessesofinterfaceonthesplittingtensilestrength.Theresultshowsthatdifferentaggregatedistil— butionsandshapesonly havelessimpactsontheultimatesplittingtensilestrength,however,thenumericalsimulationresuhsare allwithin therangeoftheexperimentalstatisticsand coincidewith thosefrom theexperimentsgiveninthe relevantliteratures. Whenthespacerwidth isselectedinaccordancewiththecurrentexperimentruleconcerned,thephenomenaofthestressconcen— trationsattheloading locationscan beeffectively alleviated,and then make the splittingtensile strength approach to the real strength ofconcrete. Th e smallerthe thicknessofthe aggregate bonding interface is, the higherthe ultimate splitting tensile strength istobe. Keywords:concrete;damage—plasticitymodel;splittingtensile strength;numerical simulation
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