DESIGN OF ADEHSIVE JOINTS IN FRP-BONDED STEEL BEAMS

2012 ◽  
Vol 12 (01) ◽  
pp. 53-73
Author(s):  
REZA HAGHANI ◽  
MOHAMMAD AL-EMRANI ◽  
ROBERT KLIGER
Keyword(s):  
Steel Structures ◽  
Adhesive Joints ◽  
Design Model ◽  
Fiber Reinforced Polymer ◽  
Steel Beams ◽  
Fiber Reinforced ◽  
Design Models ◽  
Static Tests ◽  
Cfrp Laminates ◽  
Reinforced Polymer

The use of bonded carbon fiber-reinforced polymer (CFRP) laminates to strengthen and upgrade existing structures has attracted a great deal of attention during the past two decades. Fiber-reinforced polymer (FRP) bonding has been widely researched and practiced in the strengthening of concrete members. However, when it comes to steel structures, it is somewhat limited in terms of field applications. One of the most important obstacles to the widespread use of FRP bonding in steel structures is the lack of design codes. This is mainly due to the lack of suitable design models for adhesive joints used to bond FRP laminates to steel substrates. Issues such as the lack of knowledge about the behavior of adhesive joints, the lack of suitable material models for structural adhesives, and analyzing adhesive joints are contributing to the difficulty associated with establishing design models. This paper is mainly concerned with a proposal and verification of a new design model for adhesive joints used to bond FRP laminates to steel beams. The paper, first, shortly reviews the most commonly used failure criteria and presents the background to the newly proposed model. Quasi-static tests were then performed on steel plate and full-scale beam specimens bonded with CFRP laminates to evaluate the new design model. The new design model presented in this paper was found to be accurate in terms of predicting the ultimate load and failure mode of the joints. To illustrate the application of the new design model, an example is appended to this paper.

scholarly journals Shear deformable super-convergent finite element for steel beams strengthened with glass-fiber reinforced polymer (GFRP) plate

2019 ◽  
Vol 46 (4) ◽  
pp. 338-351
Author(s):  
Phe Van Pham ◽  
Magdi Mohareb ◽  
Amir Fam
Keyword(s):  
Finite Element ◽  
Glass Fiber ◽  
Shear Deformation ◽  
Fiber Reinforced Polymer ◽  
Steel Beams ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Partial Interaction

The present study investigates the flexural behaviour of steel beams strengthened by adhesively bonding a glass-fiber reinforced polymer (GFRP) plate to one of the flanges. The model captures shear deformation effects and partial interaction between the steel and GFRP owing to the relative flexibility of the adhesive. A general closed form solution is first developed for the governing coupled system of differential equations. The solution is then used to formulate mechanics-based shape functions and develop a finite element with superior convergence characteristics. The model is used to investigate the response of multi-span continuous beams, determine the strength gained by GFRP strengthening, and quantify shear deformation effects on the response of strengthened beams. A technique capturing partial interaction effects is devised to characterize the flexural strength of Class 3 strengthened beams. A classification limit for strengthened Class 3 sections is also proposed within the framework of the Canadian Standard CAN-CSA S16 (2014).

Defects Study on Drilling of Carbon Fiber Reinforced Polymer (CFRP) Laminates

2014 ◽  
Vol 800-801 ◽  
pp. 61-65 ◽  
Author(s):  
Kun Xian Qiu ◽  
Cheng Dong Wang ◽  
Qing Long An ◽  
Ming Chen
Keyword(s):  
Carbon Fiber ◽  
Feed Rate ◽  
High Speed ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Cfrp Laminates ◽  
Drilling Performance ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The new developed carbon fiber reinforced polymer laminates are widely used in main structural components of big commercial aircrafts. Generally drilling is the final operations in manufacturing structure, which is the most important operation during assembly. Defects such as burrs and delamination always appear in the process of drilling, which makes it hard to control the drilling quality. In this research, the drilling defects of T800 CFRP laminates are evaluated by using a brad point drill and a multifacet drill in terms of drilling forces, burr defect and delamination detection. The results show that the spindle speed is the most significant factor affecting the delamination defect followed by the feed rate. High speed drilling and low feed rate could improve the surface quality and reduce the delamination. The multifacet drill showed excellent drilling performance than the brad point drill and generated smaller defects.

Failure Modes of CFRP Flexural Strengthened Steel I-Beams

2011 ◽  
Vol 471-472 ◽  
pp. 590-595 ◽  
Author(s):  
Kambiz Narmashiri ◽  
Mohd Zamin Jumaat ◽  
Nor Hafizah Ramli Sulong
Keyword(s):  
Failure Modes ◽  
Steel Structures ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Steel Beams ◽  
Numerical Studies ◽  
Reinforced Polymer ◽  
Cfrp Plate ◽  
Critical Regions ◽  
Incremental Loading

This paper presents the experimental and numerical studies on the flexural strengthened steel I-beams by using Carbon Fiber Reinforced Polymer (CFRP) strips. Nowadays, strengthening existing steel structures by using CFRP has been widely interested. One of the common usages of CFRP to strengthen steel beams is the flexural upgrading. In this case, CFRP strips are pasted on the tensile flange to improve flexural behaviors. The problems that are frequently reported for CFRP strengthened steel beams are the debonding, delaminating (peeling), and splitting. Identification these failure modes are essential to provide an appropriate level of safety for strengthened steel beams. To investigate the CFRP failure modes, four strengthened steel I-beams were chosen. The CFRP plates with different thicknesses in single and double (splice) layers were used. Both experimental test (four-points bending test) and numerical simulation (full 3D simulation with ANSYS) were employed. The incremental loading was applied until failure while deformations in the critical regions were recorded. The results reveal that for the CFRP flexural strengthened steel beams the following failure modes occurred: (a) debonding at the CFRP plate tips, (b) debonding below point loads, (c) delaminating at the ends of CFRP plate, and (d) splitting below point loads. The sequence of failure modes depended on the specifications of CFRP plate. Some recommendations are provided to overcome/retard these failures.

Numerical Investigation on Surface Crack Growth in Steel Plates Repaired With Carbon Fiber-Reinforced Polymer

2019 ◽  
Author(s):  
Zongchen Li ◽  
Xiaoli Jiang ◽  
Hans Hopman
Keyword(s):  
Crack Growth ◽  
Surface Crack ◽  
Steel Structures ◽  
Steel Plates ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Surface Cracks ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Surface Crack Growth

Abstract Fatigue crack growth is a major challenge to the structural integrity of steel structures. In technical practice, surface cracks are of great importance since cracks in components and structures often exhibit this geometry. Fiber-reinforced polymer (FRP) strengthening technology is a reliable technique to repair cracks in steel structures. Yet the investigation on FRP repairing surface cracks in steel structures is lacking. What’s more, the crack growth might cause crack-induced debonding at the interface of FRP reinforcement, generating negative effects to the reinforcement effectiveness. Unfortunately, there are limited studies in the open literature for this issue. In this paper, we conduct the investigation on surface crack growth in steel plates reinforced with Carbon Fiber-reinforced polymer (CFRP) under tensile load. Three-dimensional finite element models are built to predict the stress intensity factors of the surface cracks. The crack-induced debonding is considered in the finite element analysis by introducing the cohesive zone model and a bond failure criterion. In accordance with Paris law, surface crack growth rate of different models are predicted. The influential parameters of crack-induced debonding are analyzed by means of parametric studies. The results indicate that CFRP reinforcement could significantly decrease the surface crack growth rate, while the crack-induced debonding might generate negative effect on CFRP reinforcement. In addition, the crack-induced debonding is affected by not only the interfacial properties, but also the reinforcement scheme, such as thickness of the adhesive layer, CFRP layer number and its elastic modulus, and the depth of surface cracks.

scholarly journals Pseudo-static tests and numerical investigations of triple-tube glass fiber–reinforced polymer and steel buckling-restrained braces

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402092205
Author(s):  
Jialu Ma ◽  
Jinwei Wang ◽  
Lingxin Zhang ◽  
Xudong Zhi
Keyword(s):  
Glass Fiber ◽  
Fiber Reinforced Polymer ◽  
Spatial Structures ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Static Tests ◽  
Buckling Restrained Brace ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Buckling Restrained Braces

Long-span spatial structures are typical city landmarks. Earthquakes can cause serious damage to these structures, leading to tremendous human injury and financial loss. Therefore, it is essential to develop effective devices to enhance the performance of spatial structures. This article proposes a new triple-tube glass fiber–reinforced polymer and steel buckling-restrained brace device for reticulated shells, which integrates the light weight and high strength advantages of the composite materials. Specimens of scaled glass fiber–reinforced polymer and steel buckling-restrained braces were designed and produced, and pseudo-static tests were performed on these specimens with an MTS machine. Mechanical performance and damages were examined and compared. An elaborate finite-element model was setup, and the accuracy of this model was verified with the test data. In addition, the model was used to investigate the effect of the Pe/ Py ratio on the performance of full-scale triple-tube glass fiber–reinforced polymer and steel buckling-restrained brace devices. Finally, the lower limit of the Pe/ Py ratio for this kind of buckling-restrained brace was obtained by theoretical derivation and numerical parametric analysis.

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