Finite element modelling of debonding failures in steel beams flexurally strengthened with CFRP laminates
Finite element modelling of debonding failures in steel beams flexurally strengthened with CFRP laminates
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DOI：
10.1016/j.engstruct.2015.01.003
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发表时间：
2015-03-01
影响因子：
5.5
通讯作者：
Yu, T.
中科院分区：
文献类型：
--
作者：
Teng, J. G.;Fernando, D.;Yu, T.
可以通过将碳纤维增强聚合物（CFRP）板结合到张力面来加强钢梁的弯曲。这样的梁可能由于CFRP板在板端之一处开始的脱粘（即板端脱粘）或由于远离板端的局部损伤（例如裂纹或集中屈服）处开始的脱粘（中间脱粘）而失效。本文提出了第一个有限元（FE）的方法，能够准确预测这种剥离故障，特别注意板端剥离。在建议的有限元方法中，混合模式的凝聚力的法律是用来描绘界面行为的组合下的正应力（即模式I加载）和剪切应力（即模式II加载）;纯模式I加载或纯模式II加载下的界面行为是由双线性牵引分离模型。使用二次强度准则定义损伤起始，使用基于线性断裂能的准则定义损伤演化。详细的有限元模型的钢梁测试由以前的研究人员，和他们的预测显示与测试结果是非常一致的。采用本文提出的有限元方法，对CFRP加固钢梁的性能进行了研究，结果表明：（1）如果破坏是由板端脱粘引起的，则使用弹性模量较高和/或厚度较大的CFRP板可能会导致板端脱粘发生较早，从而导致极限荷载较低;（2）当使用短CFRP板时，板端脱粘更可能发生，正如通常预期的那样;（3）如果使用较长的板，则失效模式可能变为中间脱粘或其他失效模式，例如压缩凸缘屈曲。(C)2015爱思唯尔有限公司版权所有。
A steel beam may be strengthened in flexure by bonding a carbon fibre-reinforced polymer (CFRP) plate to the tension face. Such a beam may fail by debonding of the CFRP plate that initiates at one of the plate ends (i.e. plate end debonding) or by debonding that initiates at a local damage (e.g. a crack or concentrated yielding) away from the plate ends (intermediate debonding). This paper presents the first finite element (FE) approach that is capable of accurate predictions of such debonding failures, with particular attention to plate-end debonding. In the proposed FE approach, a mixed-mode cohesive law is employed to depict interfacial behaviour under a combination of normal stresses (i.e. mode-I loading) and shear stresses (i.e. mode-II loading); the interfacial behaviour under pure mode-I loading or pure mode-II loading is represented by bi-linear traction-separation models. Damage initiation is defined using a quadratic strength criterion, and damage evolution is defined using a linear fracture energy-based criterion. Detailed FE models of steel beams tested by previous researchers are presented, and their predictions are shown to be in close agreement with the test results. Using the proposed FE approach, the behaviour of CFRP-strengthened steel beams is examined, indicating that: (1) if the failure is governed by plate end debonding, the use of a CFRP plate with a higher elastic modulus and/or a larger thickness may lead to a lower ultimate load because plate end debonding may then occur earlier; (2) plate end debonding is more likely to occur when a short CFRP plate is used, as is commonly expected; and (3) the failure mode may change to intermediate debonding or other failure modes such as compression flange buckling if a longer plate is used. (C) 2015 Elsevier Ltd. All rights reserved.