FRP-混凝土中部裂缝处剥离有限元分析

 提出了适用于FRP-混凝土中部裂缝处剥离(IC debonding)的，基于分布裂缝混凝土模型的界面破坏模型。与大量试验结果吻合良好。 指导老师：香港理工大学滕锦光教授，清华大学叶列平、江见鲸教授 论文下载 Abstract: Reinforced concrete (RC) beams strengthened in flexure with a bonded fiber-reinforced polymer (FRP) plate may fail by intermediate crack (IC) debonding, in which debonding initiates at a critical section in the high moment region and propagates to a plate end. This paper first presents a finite-element (FE) model based on the smeared crack approach for concrete for the numerical simulation of the IC debonding process. This finite-element model includes two novel features: (1) the interfacial behavior within the major flexural crack zone is differentiated from that outside this zone and (2) the effect of local slip concentrations near a flexural crack is captured using a dual local debonding criterion. The FE model is shown to be accurate through comparisons with the results of 42 beam tests. The paper also presents an accurate and simple strength model based on interfacial shear stress distributions from finite-element analyses. The new strength model is shown to be accurate through comparisons with the test results of 77 beams, including the 42 beams used in verifying the FE model, and is suitable for direct use in design. FRP加固混凝土梁受弯剥离破坏的有限元分析 Finite Element Analysis of Intermediate Crack-Induced Debonding in FRP Strengthened RC Beams 工程力学(录用)/Engineering Mechanics (Accepted) 摘 要：FRP加固钢筋混凝土梁受弯剥离破坏是一种非常常见的破坏形式。本文首先基于微观尺度有限元分析，对受弯剥离破坏的机理进行了研究，提出了一个受弯剥离的双重剥离破坏准则，以及相应的界面粘结滑移关系，使得受弯剥离可以由基于普通弥散裂缝模型的混凝土单元来加以模拟，并开发出了相应的FRP-混凝土界面单元模型。将该界面单元嵌入通用有限元程序MSC.MARC，对45根受弯剥离破坏的试验梁进行了有限元分析。分析结果表明，本文提出的计算模型与试验结果吻合良好，可以真实模拟受弯剥离破坏过程。 关键词：混凝土梁，FRP，剥离，界面粘结，有限元，承载力 Abstract：A finite element (FE) model to simulate the intermediate crack (IC) debonding of RC beams flexually strengthened with externally bonded FRP plates is presented in this paper. A dual debonding criterion is proposed so that IC debonding can be predicted with the common smeared crack approach for concrete. Furthermore, based on meso-scale FE results, proper bond-slip models for the interface between FRP and concrete are proposed. This FE model is implemented with MSC.MARC which is a widely used FE package. Through comparisons with the test results of 45 beams, this method is shown to provide accurate predictions of IC debonding failures. Key words：RC beam, FRP, debonding, intermediate crack, finite element analysis 点击下载/Download Here Recent research on intermediate crack Debonding in FRP-strengthened RC beams Proceeding of 4th International Conference on Advanced Composite Materials in Bridges and Structures, (ACMBS IV) Calgary, Alberta, Canada, July, 2004. CDROM ABSTRACT: An important failure mode for an RC beam strengthened with an externally bonded FRP plate is debonding of the FRP plate from the soffit of the beam due to major flexural cracks. In this failure mode which is commonly referred to as intermediate crack (IC) debonding, debonding initiates at a critical section in the high moment region and then propagates to one of the plate ends. Despite many experimental and theoretical studies, accurate predictive models for IC debonding failures have not been developed. This paper presents a new smeared crack approach for the finite element simulation of the IC debonding process, in which a new model for the FRP-to-concrete interface capable of capturing the effect of local slip concentration near a flexural crack is proposed. The finite element model is shown to be accurate through comparisons with the results of 45 beam tests. The paper also presents an accurate and simple design model based on interfacial shear stress distributions from finite element analysis. The new design model is shown to be accurate through comparisons with the test results of 73 beams, including the 45 beams used in verifying the FE model. 点击下载/Download Here FRP加固混凝土梁的剥离模式 极限承载力对比 荷载位移曲线对比 裂缝图对比
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