Experimental and numerical analysis of hybrid adhesively-bonded scarf joints

Alves, D.L.; Campilho, R.D.S.G.; Moreira, R.D.F.; Silva, F.J.G.; Silva, Lucas F. M. da

doi:10.1016/j.ijadhadh.2018.05.011

Cited by 44 publications

(16 citation statements)

References 20 publications

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“…8), leading to best results with a stronger but brittle adhesive because, under these conditions, the average stress at failure is higher. These findings agree with previous results [47], relating to hybrid scarf joints between aluminium and composites. On the other hand, the adhesives' ductility is not as important as in lap joints.…”

Section: Discussion On the Joint Strengthsupporting

confidence: 94%

Application a direct/cohesive zone method for the evaluation of scarf adhesive joints

et al. 2018

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IntroductionThe use of adhesive bonds in the aerospace, aeronautical and automotive industries, among others, has assumed a high preponderance to the detriment of conventional joining methods such as riveting, bolting, brazing and welding. In fact, adhesive bonds offer several advantages such as the reduction of stress concentrations, good response to fatigue stresses, ability to bond dissimilar materials and lightness of structures. However, they also present some limitations, namely the difficulty of disassembly, high cure times (in some cases) and limited temperature and humidity conditions [1]. The strength and behaviour of adhesive bonds depends on several factors, namely the type of adhesive used, the material of the adherends, the joint configuration and dimensional factors, such as the overlap length (L O ) and the adhesive and adherends' thickness (t A and t P , respectively). There are several types of joint geometries, although the most common are single-lap, double-lap and scarf [2][3][4][5]. Scarf joints are modified butt joints that are AbstractWith the increasing use of structures with adhesive bonds at the industrial level, several authors in the last decades have been conducting studies concerning the behaviour and strength of adhesive joints. Between the available strength prediction methods, cohesive zone models, which have shown good results, are particularly relevant. This work consists of a validation of cohesive laws in traction and shear, estimated by the application of the direct method, in the strength prediction of joints under a mixedmode loading. In this context, scarf joints with different scarf angles (α) and adhesives of different ductility were tested. Pure-mode cohesive laws served as the basis for the creation of simplified triangular, trapezoidal and exponential laws for all adhesives. Their validation was accomplished by comparing the numerical maximum load (P m ) predictions with the experimental results. An analysis of peel (σ) and shear (τ) stresses in the adhesive layer was also performed to understand the influence of stresses on P m . The use of the direct method allowed obtaining very precise P m predictions. For the geometric and material conditions considered, this study has led to the conclusion that no significant P m errors are incurred by the choice of a less appropriate law or by uncoupling the loading modes.

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Section: Discussion On the Joint Strengthsupporting

confidence: 94%

Application a direct/cohesive zone method for the evaluation of scarf adhesive joints

et al. 2018

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“…Figure 8 shows the energy stored in the samples until failure. The HJs were modeled with three-stage damage and cracking processes in: The adhesive layer: Modeled by cohesive elements [3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19];The rivets: The ductile damage model with damage parameters [3,5,8,12,16,48,49,50,51];The adherends: The ductile damage model with damage parameters [3,5,8,12,16,48,49,50,51]. …”

Section: Results Analysismentioning

confidence: 99%

“…This causes a very high stress concentration and, moreover, requires the application of hole drilling. These drawbacks can be overcome by introducing an adhesive layer to the connection and thus creating a hybrid joint (HJ) (e.g., [8,9,10,11,12,13,14,15,16,17,18]). The introduction of the adhesive when fabricating clinch joints may have another advantage due to the reduction of friction coefficients between the sheets [13,14].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Single Lap Geometry in Adhesive and Hybrid Joints on Their Load Carrying Capacity

Golewski

Sadowski

2019

Materials

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The manufacturing technology for adhesive joints is not yet fully optimized, as proved by a large number of papers that have been published in recent years. Future studies on innovative techniques for fabricating adhesive joints should investigate the influence of parameters such as: (1) The shape of adhesive protrusion, (2) lap dimensions, and (3) cohesive layer reduction in the most efforted regions of the joint. With the application of additional mechanical connectors (e.g., rivets, screws, and welds) in adhesive joints, new hybrid connections can be fabricated. The number of publications in this new field is still relatively small. To fill the gap, this paper presents the results of a numerical analysis of different single lap geometries in (1) pure adhesive and (2) hybrid joints. A total of 13 different models with the same surface area of the adhesive layer were considered. In the case of hybrid joints, the adhesive surface before the application of mechanical connectors was assumed to be the same in every tested case. The numerical analysis of pure adhesive and hybrid joints revealed that the differences in strength led to a 30% decrease in the load capacity of these joints. Therefore, when designing pure adhesive and hybrid joints, special attention should be paid to the shape of the lap between the joined elements.

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“…As exposed, for predicting the strength of the FGAJs and model the load-displacement curves, the CZM approach was used. CZM is a powerful FEA method extensively used to predict the failure load of adhesive joints, 22,[54][55][56][57][58][59][60][61][62] and it was used in the present work due to the fact that this method proved to be accurate in several different scenarios which include fatigue, humidity, impact and even in MAJs. By modelling a mixed adhesive joint with several infinitesimal divisions where cohesive elements are applied, this method can be adapted to work with FGAJs.…”

Section: Numerical Proceduresmentioning

confidence: 99%

Numerical modelling of multi-material graded joints under shear loading

Reis

Carbas

Marques

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part E:

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Due to environmental concerns, modern transportation solutions demand drastic reductions of fuel consumption and emissions, which can only be achieved with advanced structures using high-performance lightweight materials. For joining these dissimilar materials, adhesive bonding appears as an optimal solution, since mechanical fastening adds weight to the structure, and welding technology is not easily applicable to reinforced plastics and composites. However, one of the major drawbacks associated with bonded joints is the presence of stress concentrations at the overlap ends, especially in single lap joints. In order to reduce these stress concentrations, several techniques have been developed. One of these is the functionally graded adhesive, in which the adhesive properties gradually vary along the overlap length, leading to a more uniform stresses distribution and improving the joint strength. However, the manufacture of an adhesive layer with properties which gradually vary is complex in practice and so is the creation of numerical models that represent these configurations. In the present work, a numerical model for different-graded distribution of adhesive properties along the overlap was developed, using programmed step functions on finite element analysis background in order to discretize and simplify the continuous properties distribution gradient. Cohesive zone modelling was introduced in the numerical model, enabling it to effectively predict graded joint strength. The model was validated with experimental results of functionally graded joints available in the literature. The numerical model developed presents itself as a powerful tool to predict joint strength for functionally graded joints, without imposing large computational demands.

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Experimental and numerical analysis of hybrid adhesively-bonded scarf joints

Cited by 44 publications

References 20 publications

Application a direct/cohesive zone method for the evaluation of scarf adhesive joints

Application a direct/cohesive zone method for the evaluation of scarf adhesive joints

The Influence of Single Lap Geometry in Adhesive and Hybrid Joints on Their Load Carrying Capacity

Numerical modelling of multi-material graded joints under shear loading

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