【摘要】：為深入研究正交異性鋼橋面板U肋-蓋板焊接節(jié)點的疲勞性能及其破壞機理,設計了6個足尺試件模型開展試驗研究。首先進行中心加載和偏心加載兩種加載工況下的靜力試驗,對焊縫附近區(qū)域的鋼板表面應力進行實測,得到熱點應力分布規(guī)律及應力集中系數(shù);隨后進行不同熱點應力幅下的高周疲勞循環(huán)加載,得到相應的疲勞破壞模式、疲勞壽命、疲勞裂紋擴展過程及速率、剛度退化等實測數(shù)據(jù)。結(jié)果表明:U肋-蓋板焊接節(jié)點的最大熱點應力位于蓋板焊趾處;節(jié)點在循環(huán)荷載作用下的疲勞裂紋擴展過程大致分為裂紋萌生、裂紋穩(wěn)定擴展、裂紋貫穿壁厚、斷裂失效4個階段,且裂紋貫穿蓋板壁厚之后的剩余疲勞壽命可忽略不計;疲勞開裂初期的裂紋擴展速率較為穩(wěn)定,裂紋貫穿蓋板厚度之后的擴展速率明顯加快;節(jié)點剛度在裂紋長度達到150 mm時開始出現(xiàn)下降趨勢,并在裂紋貫穿蓋板厚度之后發(fā)生剛度急劇退化。通過疲勞壽命數(shù)據(jù)對比,可以認為采用IIW規(guī)范的FAT100級S-N曲線對正交異性鋼橋面板U肋-蓋板焊接節(jié)點的疲勞壽命進行預測和評估是偏于安全的。
[Abstract]:In order to study the fatigue behavior and failure mechanism of U-rib-cover welded joints of orthotropic steel bridge panel, six full-scale specimen models were designed to carry out experimental research. Firstly, the stress of steel plate near the weld is measured by static test under central and eccentric loading conditions, and the stress distribution law and stress concentration factor of hot spot are obtained. The fatigue failure mode, fatigue life, fatigue crack propagation process and rate, stiffness degradation and so on are obtained by high cycle cyclic loading under different hot stress amplitudes. The results show that the maximum hot stress of the welded joint is located at the toe of the cover plate, and the fatigue crack propagation process of the joint under cyclic load is roughly divided into crack initiation, crack stable growth and crack thickness through the wall. The residual fatigue life of the crack passing through the wall thickness of the cover plate is negligible, and the crack propagation rate at the initial stage of fatigue cracking is relatively stable, and the propagation rate of the crack after the crack passing through the thickness of the cover plate is obviously accelerated. The stiffness of the joints began to decrease when the crack length reached 150 mm, and the stiffness decreased sharply after the crack penetrated through the slab thickness. Based on the comparison of fatigue life data, it is considered that it is safe to predict and evaluate the fatigue life of welded joints of orthotropic steel bridge panel U-ribbed slab by FAT100 S-N curve of IIW code.
【作者單位】： 上海交通大學船舶海洋和建筑工程學院;中交公路規(guī)劃設計院有限公司;
【基金】：上海市自然科學基金項目(14ZR1422800) 中國鐵路總公司科技研究開發(fā)計劃項目(2014G010-F) 中央級公益性科研所基本科研業(yè)務費專項資金項目(2015-9020)
【分類號】：U441.4;U445.583
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本文編號：2273905