Fatigue evaluation and CFRP strengthening of diaphragm cutouts in orthotropic steel decks
Fatigue evaluation and CFRP strengthening of diaphragm cutouts in orthotropic steel decks
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DOI：
10.12989/scs.2021.39.4.453
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发表时间：
2021-05-25
影响因子：
4.6
通讯作者：
Liu, Yongming
中科院分区：
文献类型：
--
作者：
Ke, Lu;Li, Chuanxi;Liu, Yongming
横隔膜切口开裂是威胁正交各向异性钢甲板最严重的疲劳破坏之一，其机理和裂纹处理技术研究尚不充分。在本文中，首先进行了全尺寸实验来研究涉及人工几何缺陷影响的抛光切割的疲劳性能。在此基础上，对碳纤维增强聚合物（CFRP）加固的缺陷切口进行了对比实验测试。数值有限元分析对实验结果进行了验证和解释。结果表明，车轮载荷和热残余应力的共同作用是切削齿疲劳开裂的外部驱动力。确定了初始几何缺陷是影响疲劳开裂的关键因素。疲劳评价时，可采用距开刀自由边缘6mm处的主应力作为开刀的标称应力，抛光开刀的抗疲劳性能高于AASHTO规范A级。粘结CFRP体系能有效延长缺陷断口的疲劳寿命。本研究为osd的疲劳评估和修复提供了一些新的见解。
The cracking at the transverse diaphragm cutout is one of the most severe fatigue failures threatening orthotropic steel decks (OSDs), whose mechanisms and crack treatment techniques have not been fully studied. In this paper, full-scale experiments were first performed to investigate the fatigue performance of polished cutouts involving the effect of an artificial geometrical defect. Following this, comparative experimental testing for defective cutouts strengthened with carbon fiberreinforced polymer (CFRP) was carried out. Numerical finite element analysis was also performed to verify and explain the experimental observations. Results show that the combinative effect of the wheel load and thermal residual stress constitutes the external driving force for the fatigue cracking of the cutout. Initial geometrical defects are confirmed as a critical factor affecting the fatigue cracking. The principal stress 6 mm away from the free edge of the cutout can be adopted as the nominal stress of the cutout during fatigue evaluation, and the fatigue resistance of polished cutouts is higher than Grade A in AASHTO specification. The bonded CFRP system is highly effective in extending the fatigue life of the defective cutouts. The present study provides some new insights into the fatigue evaluation and repair of OSDs.