建筑用抗震钢HRB400EⅢ级钢筋焊接接头的低周疲劳性能

中文摘要: 采用轴向应变控制方法，在MTS809拉扭复合疲劳试验机上开展了HRB400EⅢ级钢筋母材及焊接接头的低周疲劳试验，获得了母材及焊接接头的低周疲劳性能，如循环应力响应特征、循环应力-应变关系以及寿命预测公式等。通过断口电镜扫描发现，HRB400EⅢ级钢筋焊接接头的裂纹萌生于试件表面，且存在多处裂纹源。研究结果表明，焊接接头与母材的低周疲劳寿命及微观断裂机理方面均存在明显差异，并从力学性能变化的角度对引起差异的原因进行了解释。
Abstract:Thelowcyclefatigue(LCF)behavioroftheweldedjointoftheHRB400EⅢaseismicreinforcedbarspromotedintheearthquakeareasinChinawasinvestigated.TheLCFtestsunderuniaxialstraincontrolwerecarriedoutonaMTS809servo-hydraulictestingmachine.Thelowcyclefatigueproperties,suchasthecyclicstressresponsecharacteristics,thecyclicstress-strainrelationshipsandthefatiguelifepredictionmodelsofthebasemetalandtheweldedjointwereobtained.TheCoffin-Mansonparameterswerederivedfromthetestresults.TheSEMmicrographsrevealedthatmorethanonefatiguecracksinitiatedatthespecimensurfaces.Theresultsshowedthatthelowcyclefatiguelifeandthemicrofracturemechanismoftheweldedjointareobviouslydifferentfromthoseofthebasemetal.ThereasonsfortheobviousdifferenceoftheLCFpropertyandthemicrofracturemechanismoftheweldedjointwerealso revealedfromthechangeofthemechanicalproperties.