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| 考虑焊接残余应力的U肋加劲板焊缝初始裂纹特性研究 |
| Study on the initial crack characteristics of weld in U-ribbed stiffening plate considering welding residual stress |
| 投稿时间：2024-02-26 修订日期：2024-04-01 |
| DOI： |
| 中文关键词: U肋加劲板 焊接残余应力 应力比 初始裂纹角度 有效角度区间 裂纹形状比 |
| 英文关键词:U-rib stiffened plate welding residual stress stress ratio initial crack angle effective angle range crack shape ratio |
| 基金项目:国家自然科学(51978571,52378197)；陕西省杰出青年(2021JC-41)；陕西省重点研发计划(2022SF-199) |
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| 中文摘要: |
| U肋加劲板焊缝作为钢桥面板疲劳危害最为严重的构造细节,对该位置处的裂纹扩展特性的研究尚显不足。本文考虑了焊接残余应力的影响,研究U肋加劲板焊趾初始裂纹的扩展特性及裂纹的初始角度效应,得到初始裂纹具备扩展能力的有效角度区间,推导了有效角度区间数学模型。研究表明：初始裂纹角度越大,裂纹前缘有效应力强度因子幅值越大,裂纹扩展速率越快,且裂纹为I型主导的复合型裂纹,且初始裂纹角度越大,II-III型特征越强；考虑焊接残余应力时,裂纹前缘应力比随着裂纹深度的增加而增大,随着初始裂纹角度和形状比的增大,裂纹前缘应力比变化不大,不同初始裂纹角度和形状比下应力比与裂纹深度呈线性正相关；焊接残余应力明显增大了裂纹可扩展的初始角度区间,且有效角度区间随着裂纹形状比的增大而减小。 |
| 英文摘要: |
| The weld seam of U-rib stiffened plate is the most serious structural detail that poses fatigue hazards to the steel bridge deck. The crack growth characteristics at this location have not been studied enough. The influence of welding residual stresses is considered to study the growth characteristics of initial cracks and the initial angle effect of cracks at the weld toe of U-rib stiffened plate. The effective angle interval for initial cracks to have the ability to expand is obtained, and the corresponding fitting calculation formula is derived. The results show that the larger the initial crack angle, the larger the amplitude of the effective stress intensity factor of the fatigue crack, and the faster the crack growth rate. And the cracks are composite cracks dominated by type I, and the larger the initial angle of the crack, the stronger the characteristics of Type II-III. When considering welding residual stress, the stress ratio at the crack front edge increases with the increase of crack depth. As the initial crack angle and shape ratio increase, the stress ratio at the crack front edge does not change much. Under different initial crack angles and shape ratios, the stress ratio is linearly positively correlated with the crack depth. The welding residual stress significantly increases the initial angle range at which cracks can propagate, and the effective angle range decreases with the increase of crack shape ratio. |
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