【摘要】：近些年來,隨著交通運輸荷載不斷增加,焊接鋼橋的疲勞問題越來越顯著,成為國內(nèi)外研究的熱點之一。但是,正交異性鋼橋面板作為大中跨鋼橋的主要形式之一,其疲勞問題的研究還不夠深入,本文在回顧了鋼橋疲勞壽命研究的基礎(chǔ)上,基于帶初始裂紋的模型,運用斷裂力學(xué)理論研究正交異性鋼橋面板與縱肋焊接細(xì)節(jié)處的疲勞壽命。 本文運用斷裂力學(xué)的方法,分析了正交異性鋼橋面板與縱肋焊接細(xì)節(jié)處疲勞裂紋的應(yīng)力強(qiáng)度因子變化規(guī)律以及擴(kuò)展壽命,具體分為以下幾個方面： 1.正交異性鋼橋面板與縱肋焊接細(xì)節(jié)二維有限元模型的建立和應(yīng)力強(qiáng)度因子計算及應(yīng)力強(qiáng)度因子變化規(guī)律 在正交異性鋼橋面板與縱肋焊接部位引入初始裂紋,建立二維有限元模型,用奇異單元構(gòu)造裂紋附近單元,基于大型通用有限元軟件ANSYS編制通用的命令流和程序,計算得到正交異性鋼橋面板與縱肋焊接部位裂紋尖端的應(yīng)力強(qiáng)度因子。通過改變橋面板厚度、初始裂紋長度以及縱肋的高度等參數(shù),分析了應(yīng)力強(qiáng)度因子的變化規(guī)律,分析表明,控制好初始裂紋長度以及增大橋面板厚度可以有效地提高此細(xì)節(jié)的疲勞壽命。 2.正交異性鋼橋面頂板與縱肋焊接細(xì)節(jié)疲勞擴(kuò)展壽命預(yù)測 根據(jù)Eurocode規(guī)范對名義應(yīng)力的要求,利用有限元計算方法計算得到的應(yīng)力強(qiáng)度因子值,進(jìn)而運用Paris疲勞擴(kuò)展模型,計算得到正交異性鋼橋面板與縱肋焊接細(xì)節(jié)的疲勞擴(kuò)展壽命,擬合S-N曲線并與Eurocode規(guī)范中S-N曲線進(jìn)行比較,結(jié)果表明,本文計算得到的S-N曲線與Eurocode規(guī)范中的S-N曲線擬合情況良好,本文的計算結(jié)果具有一定的參考價值。
[Abstract]:In recent years, with the increasing traffic load, the fatigue problem of welded steel bridges is becoming more and more significant, which has become one of the research hotspots at home and abroad. However, as one of the main forms of large and medium span steel bridges, the fatigue problem of orthotropic steel bridge slabs is not deeply studied. based on the review of the fatigue life of steel bridges, the model with initial cracks is based on the study of fatigue life of steel bridges. The fatigue life of orthotropic steel bridge deck and longitudinal ribbed welding details is studied by using fracture mechanics theory. In this paper, the variation law of stress intensity factor and propagation life of fatigue crack in welding details of orthotropic steel bridge deck and longitudinal ribs are analyzed by means of fracture mechanics, which can be divided into the following aspects: 1. Establishment of two-dimensional finite element model for welding details of orthotropic steel bridge slabs and longitudinal ribs, calculation of stress intensity factors and variation of stress intensity factors initial cracks are introduced into the welding parts of orthotropic steel bridge slabs and longitudinal ribs. The two-dimensional finite element model is established, the element near the crack is constructed by singular element, and the general command flow and program are compiled based on the large-scale general finite element software ANSYS. The stress intensity factors at the crack tip of orthotropic steel bridge deck and longitudinal ribs are calculated. By changing the thickness of bridge deck, the initial crack length and the height of longitudinal ribs, the variation law of stress intensity factor is analyzed, and the analysis shows that, Controlling the initial crack length and increasing the thickness of bridge deck can effectively improve the fatigue life of this detail. 2. Prediction of fatigue expansion Life of orthotropic Steel Deck Roof and Longitudinal Rib Welding details according to the requirements of Eurocode Code for nominal stress, the stress intensity factor calculated by finite element method is calculated by finite element method, and then the Paris fatigue expansion model is used. The fatigue life of orthotropic steel bridge deck and longitudinal ribbed welding details is calculated, and the S 鈮，

本文編號：2477394