Failure Assessment of Steel/CFRP Double Strap Joints

Majidi, H.R.; Razavi, Seyed Mohammad Javad; Berto, Filippo

doi:10.3390/met7070255

Cited by 22 publications

(16 citation statements)

References 48 publications

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“…Their application together with FRP strengthening on stiff elements (reinforced concrete beams, stiff steel beams, or columns) is justified and effective [12], because joined components have low elongation limits, and, thus, they tolerate the use of adhesives with low deformability. The same situation (with positive results) applies to the use of an epoxy to strengthen a thin metal profile on a relatively short length, where the deformability of the adhesive is of lesser importance [13].…”

Section: Introductionmentioning

confidence: 95%

The Methacrylate Adhesive to Double-Lap Shear Joints Made of High-Strength Steel—Experimental Study

et al. 2019

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In typical technical applications, steel components are usually connected by welding or with mechanical connectors. An alternative solution, typical in the aviation and automotive industry, but not widespread in engineering structures, is to join thin sheet metal using adhesives. The article presents an experimental study of adhesive joints used in overlap connections subjected to static tension. A methacrylate adhesive, selected experimentally from a range of adhesives, which combines the optimum strength and strain properties, was tested. The laboratory tests were carried out on double-lap specimens made of high-strength Domex 700 steel. On the basis of the experimental results, the behavior of the specimens and their failure mechanism, depending on the anchorage lengths used (200, 300 and 400 mm), are described. The tests confirmed the effectiveness of the selected methacrylate adhesive in a practical application. It was shown that with the appropriate anchorage length (adequate to the type of steel components and the joint geometry) between 300 and 400 mm, the capacity of the adhesive joint is higher than the capacity of a single steel component. Two types of specimen behavior were recognized: Quasi-brittle, which occurs at the anchorage length of 200 mm, and ductile, observed for 300 mm and 400 mm anchoring. In addition, thanks to the optical measurement method used, a detailed strain distribution on the specimen surface was determined. The data will be used for subsequent validation of an analytical and numerical model.

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Section: Introductionmentioning

confidence: 95%

The Methacrylate Adhesive to Double-Lap Shear Joints Made of High-Strength Steel—Experimental Study

et al. 2019

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“…On the other hand, in some researches dealing with experiments on steel/CFRP DSJs, complicated numerical were applied to the FE analyses. For instance, it can be referred to three researches [16,32,33]. According to the mentioned discussions, it can be expressed that if one of the failure model succeeded with high performance in predicting the failure loads values of the tested DSJs does not delivered this message that other failure models could not be utilized and developed.…”

Section: Limitations and Advantages Of The Cns Criterion For Dsjsmentioning

confidence: 99%

A strain-based criterion for failure load prediction of steel/CFRP double strap joints

Razavi

Ayatollahi

Majidi

et al. 2018

Composite Structures

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One of the most effective approaches to improve the strength of steel structures is using the carbon fiber reinforced polymer (CFRP) as externally-bonded sheets. In this paper, a strain-based failure criterion, namely the critical normal strain (CNS) is employed to predict the failure load of adhesively bonded double strap joints which are made of CFRP and steel plates. According to this approach, the adhesive joint fails when the normal strain along the adhesive mid-line attains a critical value at a critical distance. This work is based on a two-dimensional linear elastic finite element analysis. Failure load capacities are estimated theoretically for steel/CFRP double strap joints with different bonding lengths. The predicted values of failure loads are compared with the experimental data reported in literature. It is shown that a good consistency exists between the experimental failure loads and the theoretical predictions based on the new strain-based criterion. x distance from the bonding edge MHSM modified Hart smith model PCNS theoretical failure load predicted by CNS criterion PExp. experimental failure load SLJ single lap joint 1. Introduction Carbon fibre reinforced polymer (CFRP) sheets have many applications in industrial components, for instance they are used in order to increase the service life and load carrying capacities of damaged steel 3 structures. Nowadays, Due to the reduced weight and cost of CFRP laminates, they are often applied in retrofitting of steel structures instead of utilizing the conventional mechanical fastening procedures like welding or bolting. In huge industries like aerospace, wind energy, marine structures, etc., application of CFRP laminates is widely growing. One of the major applications of CFRP laminates is to reduce the overall weight of structures. For instance, it can be pointed to Boeing 787 aircraft, in which 43% of metal structures including fuselage, wing, etc. were replaced by CFRP laminates. Therefore, since CFRP have attracted considerable attention as a new retrofitting material to increase the LBC and the service life of structural components, proposing a suitable failure prediction model to estimate the load bearing capacities (LBCs) of the steel/CFRP bonded joints can be very necessary. Up to now, many approaches have been proposed to analyze the behavior of steel components strengthened with CFRP patches [1-5], including nonlinear theory [6], digital image correlation (DIC) [7-10], extended finite element method (XFEM) [11, 12] and cohesive zone model (CZM) [13-16].Determination of failure mechanisms in steel/CFRP adhesive bonded joints is an important issue due to its undeniable effect on the operational life of the components. Several failure criteria have been proposed by researchers to predict the failure load of adhesively bonded joints. The majority of the available failure criteria are based on stress, strain or energy condition in the bond layer [17][18][19][20][21][22][23][24]. Due to their importance shear stress and normal stress (also known ...

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“…The failure assessment of double strap joints made with steel and CFRP was performed by Majidi et al, and by using a proposed approach (point stress method), the authors were able to predict the failure load under quasi‐static conditions, a method found to be in good agreement with experimental tests. More recently, Razavi et al presented a strain‐based criterion to predict the failure load of the same type of joints (based on a two‐dimensional linear elastic finite element analysis), being able to present a good consistency in its predictions and comparing well with experimental results found in the literature.…”

Section: Introductionmentioning

confidence: 99%

Fatigue performance of single lap joints with CFRP and aluminium substrates prior and after hygrothermal aging

Machado

Marques

Barbosa

et al. 2019

Fatigue Fract Eng Mat Struct

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Adhesive bonding has been extensively used to join composites and aluminium alloys in the automotive industry, but a deeper understanding of its fatigue behaviour is still required. This work presents a novel evaluation of the combined performance of joints manufactured with carbon fibre reinforced plastic (CFRP) and aluminium substrates subjected to fatigue loads in the unaged, hygrothermally aged, and dried after hygrothermal aging states. The experimental results allowed to conclude that the fatigue performance of joints can be affected by changes induced by the drying process or losses in the interface strength and that dissimilar combination of substrates sustains higher number of cycles to failure. The fatigue performance of joints with dissimilar substrates was found to be better than that of joints with similar substrates, which can be attributed to the lower stresses acting on the adhesive layer. The presence of water has also noticeably changed the fatigue performance of joints with dissimilar substrates.

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Failure Assessment of Steel/CFRP Double Strap Joints

Cited by 22 publications

References 48 publications

The Methacrylate Adhesive to Double-Lap Shear Joints Made of High-Strength Steel—Experimental Study

The Methacrylate Adhesive to Double-Lap Shear Joints Made of High-Strength Steel—Experimental Study

A strain-based criterion for failure load prediction of steel/CFRP double strap joints

Fatigue performance of single lap joints with CFRP and aluminium substrates prior and after hygrothermal aging

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