基于断裂力学的横隔板弧形切口疲劳裂纹扩展行为预测方法

Prediction Method for Fatigue Crack Propagation Behavior of Arc Shaped Cutouts in Transverse Diaphragms Based on Fracture Mechanics

摘要

正交异性钢桥面板(OSBD)因其承载力高、跨越能力强在桥梁工程中得到广泛应用，但在服役过程中OSBD横隔板弧形切口处因应力集中效应易发生疲劳开裂．基于线弹性断裂力学理论(LEFM)，采用围线积分方法计算了弧形切口处复合型(Ⅰ型和Ⅱ型)裂纹尖端的应力强度因子，在此基础上根据最大切应力准则确定复合型裂纹扩展时的偏转角度，通过网格的重划分实现疲劳裂纹的动态扩展，从而预测在移动轴载作用下弧形切口处的疲劳裂纹扩展行为．研究结果表明，在移动轴载作用下弧形切口处于复杂应力状态下，采用动态裂纹扩展技术能够实现疲劳裂纹扩展路径的捕捉，结合Q420qD钢的疲劳裂纹扩展速率试验实现弧形切口处疲劳裂纹扩展路径及疲劳寿命的预测．

Abstract

Orthotropic steel bridge decks(OSBDs)，owing to their high load-carrying capacity and outstanding span- ning ability，have been widely used in bridge engineering applications. However，during service，fatigue cracking is prone to occur at the arc-shaped cutouts of transverse diaphragms due to stress concentration. Based on linear elastic fracture mechanics(LEFM)，the stress intensity factors at the crack tip of the arc-shaped cutout under mixed-mode loading(mode Ⅰ and mode Ⅱ)are calculated using the contour integral method. The deflection angle is then deter- mined according to the maximum tangential stress criterion. Fatigue crack growth is simulated dynamically through mesh redefinition，enabling the prediction of fatigue crack propagation behavior at arc-shaped cutouts under moving axle loads. The results indicate that the arc-shaped cutouts are subjected to a complex stress state under moving axle loads. The adoption of dynamic crack propagation techniques enables accurate tracking of crack paths. By incorporat- ing experimentally determined crack growth rates for Q420qD steel，the propagation paths and fatigue life of cracks at the arc-shaped cutout in the transverse diaphragm can be predicted.

关键词

正交异性钢桥面板 / 线弹性断裂力学 / 疲劳裂纹扩展速率 / 疲劳裂纹扩展行为

Key words

orthotropic steel bridge deck(OSBD) / linear elastic fracture mechanics / fatigue crack growth rate / fatigue crack propagation behavior

参考文献

[1] Yan F, Chen W Z, Lin Z B. Prediction of fatigue life of welded details in cable-stayed orthotropic steel deck bridges[J]. Engineering Structures, 2016, 127:344-358.

[2] Tai M, Arima Y, Shimozato T. Fatigue strength enhancement by structural modification of transverse to longitudinal rib connections in orthotropic steel decks with open ribs[J]. Engineering Failure Analysis, 2020, 117:104954.

[3] Di J, Ruan X Z, Zhou X H, et al. Fatigue assessment of orthotropic steel bridge decks based on strain monitoring data[J]. Engineering Structures, 2021, 228 : 111437.

[4] Wang P, Pei X J, Dong P S, et al. Traction structural stress analysis of fatigue behaviors of rib-to-deck joints in orthotropic bridge deck[J]. International Journal of Fatigue, 2019, 125:11-22.

[5] Li J, Zhang Q H, Bao Y, et al. An equivalent structural stress-based fatigue evaluation framework for rib-to-deck welded joints in orthotropic steel deck[J]. Engineering Structures, 2019, 196:109304.

[6] Gao T, Yuanzhou Z Y, Ji B H, et al. Determination of the critical fatigue crack length for orthotropic steel decks[J]. Journal of Constructional Steel Research, 2023, 205:107904.

[7] Huang Y, Zhang Q H, Bao Y, et al. Fatigue assessment of longitudinal rib-to-crossbeam welded joints in orthotropic steel bridge decks[J]. Journal of Constructional Steel Research, 2019, 159:53-66.

[8] Fu Z Q, Wang Y X, Ji B H, et al. Effects of multiaxial fatigue on typical details of orthotropic steel bridge deck[J]. Thin-Walled Structures, 2019, 135:137-146.

[9] Westergaard H M. Bearing pressures and cracks :Bearing pressures through a slightly waved surface or through a nearly flat part of a cylinder,and related problems of cracks[J]. Journal of Applied Mechanics, 1939, 6(2):A49-A53.

[10] Williams M L. On the stress distribution at the base of a stationary crack[J]. Journal of Applied Mechanics, 1957, 24(1):109-114.

[11] Carpinteri A. Advanced Structural Mechanics[M]. Boca Raton: CRC Press, 2017.

[12] Shih C F, Asaro R J. Elastic-plastic analysis of cracks on bimaterial interfaces : Part Ⅰ —Small scale yielding[J]. Journal of Applied Mechanics, 1998, 55(2): 299-316.

[13] Dassault Systèmes Simulia Corp. ABAQUS 6.14 Analysis User’s Guide[M]. Providence: Dassault Systèms Simulia Corp., 2014.

[14] Paris P, Erdogan F. A critical analysis of crack propagation laws[J]. Journal of Basic Engineering, 1963, 85(4):528-533.

[15] ISO 12108 Metallic Materials—Fatigue Testing—Fatigue Crack Growth Method[S]. London: British Standards Institution, 2018.

[16] GB/T6398金属材料疲劳试验疲劳裂纹扩展方法[S]. 北京: 中国标准出版社, 2017.

[17] GB/T6398 Metallic Materials—Fatigue Testing—Fatigue Crack Growth Method[S]. Beijing: Standards Press of China, 2017(in Chinese).

[18] BS 5400-2 Steel,Concrete and Composite Bridges.Specification for Loads[S]. London: British Standards Institution, 2006.

[19] JTGD 60公路桥涵设计通用规范[S]. 北京: 人民交通出版社, 2015.

[20] JTGD 60 General Specifications for Design of High-way Bridges and Culverts[S]. Beijing: China Communications Press, 2015(in Chinese).

基金资助

国家自然科学基金资助项目(52375376)