基于断裂力学的正交异性钢桥面板与纵肋焊接细节疲劳寿命评估
发布时间：2019-05-15 09:14
【摘要】：近些年来,随着交通运输荷载不断增加,焊接钢桥的疲劳问题越来越显著,成为国内外研究的热点之一。但是,正交异性钢桥面板作为大中跨钢桥的主要形式之一,其疲劳问题的研究还不够深入,本文在回顾了钢桥疲劳寿命研究的基础上,基于带初始裂纹的模型,运用断裂力学理论研究正交异性钢桥面板与纵肋焊接细节处的疲劳寿命。 本文运用断裂力学的方法,分析了正交异性钢桥面板与纵肋焊接细节处疲劳裂纹的应力强度因子变化规律以及扩展寿命,具体分为以下几个方面： 1.正交异性钢桥面板与纵肋焊接细节二维有限元模型的建立和应力强度因子计算及应力强度因子变化规律 在正交异性钢桥面板与纵肋焊接部位引入初始裂纹,建立二维有限元模型,用奇异单元构造裂纹附近单元,基于大型通用有限元软件ANSYS编制通用的命令流和程序,计算得到正交异性钢桥面板与纵肋焊接部位裂纹尖端的应力强度因子。通过改变桥面板厚度、初始裂纹长度以及纵肋的高度等参数,分析了应力强度因子的变化规律,分析表明,控制好初始裂纹长度以及增大桥面板厚度可以有效地提高此细节的疲劳寿命。 2.正交异性钢桥面顶板与纵肋焊接细节疲劳扩展寿命预测 根据Eurocode规范对名义应力的要求,利用有限元计算方法计算得到的应力强度因子值,进而运用Paris疲劳扩展模型,计算得到正交异性钢桥面板与纵肋焊接细节的疲劳扩展寿命,拟合S-N曲线并与Eurocode规范中S-N曲线进行比较,结果表明,本文计算得到的S-N曲线与Eurocode规范中的S-N曲线拟合情况良好,本文的计算结果具有一定的参考价值。
[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，
本文编号：2477394
[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，
本文编号：2477394
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