FRP布-混凝土界面细观力学研究 FRP布-混凝土界面细观力学研究简介 由于FRP布与混凝土间的破坏都是发生在很小尺度上,因此有必要引入细观力学研究 论文下载 Meso-scale finite element model for FRP sheets/plates bonded to concrete. Engineering Structures. 2005. 27(4). 564- 575 ABSTRACT External bonding of fiber reinforced polymer (FRP) plates or sheets has recently emerged as a popular method for the strengthening of reinforced concrete (RC) structures. The behavior of such FRP-strengthened RC structures is often controlled by the behavior of the interface between FRP and concrete, and this interfacial behavior is commonly studied through a pull test in which an FRP sheet or plate is bonded to a concrete prism and is subject to tension. In this paper, a meso-scale finite element (FE) model implemented with the MSC.MARC program is presented for the simulation of interfacial debonding failures in a pull test. In this model, very small nearly square elements (0.25 mm to 0.5mm in size) are used with the fixed angle crack model (FACM) to capture the development and propagation of cracks in the concrete layer adjacent to the adhesive layer. The effect of element size is taken into account in modeling both the tensile and shear behavior of cracked concrete. Comparisons between the predictions of this model and test results are presented to demonstrate the capability and accuracy of this FE model. The debonding mechanism is also examined using results obtained with the FE model. Finally, a method for the determination of the local bond-slip curve of the FRP-to-concrete interface from the FE results is described. 工程力学(录用)/Engineering Mechanics (Accepted) 摘 要:外贴FRP片材加固混凝土结构技术近来发展迅速,其界面粘结性能是控制其加固效果的关键。本文基于FRP与混凝土界面面内剪切试验,采用细观单元有限元模型对其界面粘结性能进行了研究。在该模型中,混凝土和FRP片材都使用非常小的单元加以模拟,通过调整混凝土材料的本构模型来考虑单元尺寸的影响。FRP单元和混凝土单元直接连接,通过混凝土单元的断裂破坏来模拟FRP和混凝土界面的宏观剥离破坏过程。通过与大量面内剪切试验结果对比,验证了该细观有限元模型的正确性,并基于细观有限元分析结果,对界面剥离破坏机理进行了讨论。 Abstract:External bonding of fiber reinforced polymer (FRP) plates or sheets has recently emerged as a popular method for the strengthening of reinforced concrete (RC) structures. The behavior of such FRP-strengthened RC structures is often controlled by the behavior of the interface between FRP and concrete. In this paper, a meso-scale finite element (FE) model is presented for the simulation of interfacial debonding failures in FRP-to-concrete bonded joints in pull test. In this model, very small elements (0.25 mm to 0.5mm in size) are used with crack band model to capture the development and propagation of cracks in the concrete layer adjacent to the adhesive layer. The effect of element size is taken into account in modeling both the tensile and shear behavior of cracked concrete. Comparisons between the predictions of this model and test results are presented to demonstrate the capability and accuracy of this FE model. The debonding mechanism is also examined using results obtained with the FE model. Key words:FRP, concrete, strengthen, bond, debonding, finite element analysis Bond-slip models for FRP sheet/plate-to-concrete interfaces, Abstract: A meso-scale finite element model is first presented for simulating the debonding behavior of FRP-to-concrete bonded joints in simple shear tests. In this model, both the FRP plate/sheet and the concrete are modeled using elements of mesoscopic sizes so that the shapes and paths of cracks during the entire debonding process can be appropriately captured. Results obtained from this model are next presented to provide insight into the debonding failure process. Finally, based on a finite element parametric study and existing test results, three bond-slip models of different levels of sophistication are presented. These proposed models are far more accurate than all existing bond-slip models.
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