【摘要】：為研究人工蝕坑對復(fù)雜應(yīng)力場下鋼橋焊接接頭疲勞壽命的影響規(guī)律,以45°傾角全熔透承載角焊縫十字形焊接接頭為研究對象,構(gòu)造兩種不同深度的人工半球形蝕坑模擬實際腐蝕情況;對不同蝕坑深度下的焊接接頭進(jìn)行軸向拉伸疲勞試驗,建立疲勞缺口系數(shù)與蝕坑深度的關(guān)系;提出一種考慮蝕坑深度和應(yīng)力幅的腐蝕疲勞壽命影響系數(shù)定義方式。結(jié)果表明:在相同蝕坑半徑下,隨著蝕坑深度的增加,疲勞缺口系數(shù)及其變化率均增大,疲勞缺口敏感系數(shù)為0.389;不同蝕坑深度和應(yīng)力幅下焊接接頭的疲勞壽命不同,蝕坑深度對疲勞壽命的影響更靈敏;基于腐蝕疲勞壽命影響系數(shù)得到的疲勞壽命預(yù)測值與試驗值最大相對誤差為-21.5%,表明兩者吻合較好,因此環(huán)境腐蝕下應(yīng)綜合考慮蝕坑深度和應(yīng)力幅對焊接接頭疲勞壽命降低程度的影響。
[Abstract]:In order to study the effect of artificial pit on fatigue life of welded joint of steel bridge under complex stress field, 45 擄inclination angle full penetration bearing angle weld cross welded joint is taken as the object of study. Two kinds of artificial hemispherical pits with different depths were constructed to simulate the actual corrosion conditions, and the axial tensile fatigue tests of welded joints with different depth of corrosion pits were carried out to establish the relationship between the fatigue notch coefficient and the depth of the pits. A method of defining the influence coefficient of corrosion fatigue life considering the depth and stress amplitude of corrosion pit is proposed. The results show that with the increase of pit depth, the fatigue notch coefficient and its change rate increase, and the fatigue notch sensitivity coefficient is 0.389, and the fatigue life of welded joint is different with different pit depth and stress amplitude. The influence of pit depth on fatigue life is more sensitive, and the maximum relative error between the predicted value of fatigue life and the test value is -21.5, which shows that the two parameters are in good agreement with each other. Therefore, the effect of pit depth and stress amplitude on fatigue life of welded joints should be considered.
【作者單位】： 寧波大學(xué)建筑工程與環(huán)境學(xué)院;西南交通大學(xué)土木工程學(xué)院;
【基金】：國家自然科學(xué)基金(51378430,51378431) 浙江省自然科學(xué)基金(LQ17E080005)
【分類號】：U441.4;U445.583

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