Fatigue strengthening of damaged metallic beams using prestressed unbonded and bonded CFRP plates
Fatigue strengthening of damaged metallic beams using prestressed unbonded and bonded CFRP plates
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DOI：
10.1016/j.ijfatigue.2012.03.006
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发表时间：
2012-11-01
影响因子：
6
通讯作者：
Galli, M.
中科院分区：
文献类型：
--
作者：
Ghafoori, E.;Motavalli, M.;Galli, M.
传统上，粘合纤维增强聚合物（FRP）增强系统被认为是提高疲劳金属结构寿命的有效方法，并引起了广泛的研究关注。然而，疲劳载荷下粘合 FRP 加固系统的性能基本上取决于 FRP 与金属的粘合行为。本文开发了一种预应力无粘结钢筋（PUR）系统。所提出的 PUR 系统可用作粘合 FRP 增强材料的替代方案，特别是当人们担心高环境温度、湿气、水和疲劳载荷对 FRP 与金属粘合行为的影响时。将 PUR 系统加固的裂缝梁的性能与预应力粘结加固 (PBR) 系统加固的裂缝梁的性能进行了比较。开发了一种理论方法来估计足以阻止疲劳裂纹扩展 (FCG) 的预应力水平。此外，该方法还用于检查带有负载的强化梁的不同被动、半主动和主动裂纹模式。还研究了预应力 FRP 板在裂纹尖端附近形成压应力场的机制。进行了有限元（FE）建模，并将结果与实验结果进行了比较。 (C) 2012 Elsevier Ltd. 保留所有权利。
Bonded fiber reinforced polymers (FRPs) reinforcement systems have traditionally been found to be an efficient method for improving the lifespan of fatigued metallic structures and have attracted much research attention. Nevertheless, the performance of a bonded FRP reinforcement system under fatigue loading is basically dependent on the FRP-to-metal bond behavior. In this paper, a prestressed unbonded reinforcement (PUR) system was developed. The proposed PUR system can be used as an alternative to bonded FRP reinforcement, particularly when there is concern about the effects of high ambient temperatures, moisture, water and fatigue loading on the FRP-to-metal bond behavior. The performance of cracked beams strengthened by the PUR system was compared with that of cracked beams strengthened by the prestressed bonded reinforcement (PBR) system. A theoretical method was developed to estimate the level of prestressing sufficient to arrest fatigue crack growth (FCG). Furthermore, the method was used to examine different passive, semi-active and active crack modes with a loaded, strengthened beam. The mechanism by which a prestressed FRP plate forms a compressive stress field at the vicinity of the crack tip was also examined. Finite element (FE) modeling was conducted and the results were compared with experimental results. (C) 2012 Elsevier Ltd. All rights reserved.