Effect of surface treatment on the shear strength of aluminium adhesive single-lap joints for automotive applications (original) (raw)
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Mechanics Based Design of Structures and Machines, 2020
Surface roughness obtained from different preparation processes such as sanding, shot blasting, and sand blasting were considered in this study. The effects of surface roughness on shear strength of single-lap adhesive joint were examined. 2024-T3 aluminum sheets were cut into standard pieces and then sanded with seven sandpapers with different mesh, shot blasted for four different duration times and sandblasted under four different pressures. Pairs of prepared surfaces were attached using Araldite 2015 adhesive with high viscosity and HPL1012/HPH112 epoxy adhesive with low viscosity. Results show that the ultimate lap shear strength of the sanded samples initially increase and then decrease as surface roughness is increased. The lap joint strength continuously increases as the surface roughness of shot blasted and sand blasted samples are increased. In sanding, the optimum surface roughness is different for both high and low viscosity adhesives. However, for shot blasting and sand blasting, the optimum surface roughness is the same for both adhesive types. The maximum ultimate lap shear strength of joints for both types of adhesives obtained for sand blasting under 0.6 MPa pressure with 0.6 lm surface roughness.
International Journal of Adhesion and Adhesives, 2018
Fatigue is a crucial type of loading for many structural components that contain adhesive bonding systems such as the automotive industry. One of the main advantages of adhesives is their weight-reduction aptitudes. Furthermore, adhesively bonded joints allow a good damping to the fatigue's solicitation with fewer sources of stress concentration. In addition, a suitable surface treatment allows a great joint interface adhesion under cyclic loading. Hence, the mechanical preparation of the bonded surface influences directly the bonded joint performance. Therefore, a careful consideration should be given to the choice of the bonded adhesive thickness. The aim of this paper is to investigate the influence of surface roughness of an aluminium alloy and the adhesive thickness of a one-component polyurethane adhesive, to be used in several parts for buses structure, on the fatigue behaviour of single lap joints. To achieve this purpose, four different surface roughnesses were prepared on aluminium specimens, with an arithmetic average height from Ra ≈ 0.6 µm to Ra ≈ 1.5 µm. Bonded specimens with four adhesive 2 thicknesses from 0.3 mm to 2 mm were manufactured and tested in dynamic tests. The results confirm that there is an optimum combination of surface roughness and adhesive thickness providing the maximum fatigue life. Moreover, good agreement was found between this investigation and a previous work using the same parameters under static loading.
A Review on Adhesively Bonded Aluminium Joints in the Automotive Industry
Metals
The introduction of adhesive bonding in the automotive industry is one of the key enabling technologies for the production of aluminium closures and all-aluminium car body structures. One of the main concerns limiting the use of adhesive joints is the durability of these system when exposed to service conditions. The present article primarily focuses on the different research works carried out for studying the effect of water, corrosive ions and external stresses on the performances of adhesively bonded joint structures. Water or moisture can affect the system by both modifying the adhesive properties or, more importantly, by causing failure at the substrate/adhesive interface. Ionic species can lead to the initiation and propagation of filiform corrosion and applied stresses can accelerate the detrimental effect of water or corrosion. Moreover, in this review the steps which the metal undergoes before being joined are described. It is shown how the metal preparation has an importan...
The Journal of Adhesion, 2014
The single-lap joint is the most commonly used, although it endures significant bending due to the non-collinear load path, which negatively affects its load bearing capabilities. The use of material or geometric changes is widely documented in the literature to reduce this handicap, acting by reduction of peel and shear peak stresses or alterations of the failure mechanism emerging from local modifications. In this work, the effect of using different thickness adherends on the tensile strength of single-lap joints, bonded with a ductile and brittle adhesive, was numerically and experimentally evaluated. The joints were tested under tension for different combinations of adherend thickness. The effect of the adherends thickness mismatch on the stress distributions was also investigated by Finite Elements (FE), which explained the experimental results and the strength prediction of the joints. The numerical study was made by FE and Cohesive Zone Modelling (CZM), which allowed characterizing the entire fracture process. For this purpose, a FE analysis was performed in ABAQUS 1 considering geometric non-linearities. In the end, a detailed comparative evaluation of unbalanced joints, commonly used in engineering applications, is presented to give an understanding on how modifications in the bonded structures thickness can influence the joint performance.
Design And Analysis Of Aluminium Adhesive Joints
2017
Adhesive bonding is widely used for sheet metal joining. Majority of automobile, aerospace parts, mainly their body components are joined together by different types of adhesives. So their growing demand needs the detailed study of strength analysis of adhesive joints. Investigation on single lap adhesive joint is to be done for various applications. Overlap length, load and Adhesive layer thickness has to be varied in the defined range & analysis is done by to see the nature of changes in the joint. FE analysis is done by using Ansys to observe the nature of changes in the joint. Validation by Mechanical testing is done by using Universal Testing Machine up to ultimate limit. Overall joint strength is related to maximum force that can be sustained by joint. The overlap at which the maximum force is required to break the joint is the length which can considered as optimum adhesive overlap length https://journalnx.com/journal-article/20150402
Engineering Fracture Mechanics, 2017
The automotive industry is increasing, nowadays, its use of high performance structural adhesives in order to reduce vehicle weight and increase the crash resistance of automotive structures. One-component polyurethane adhesives are attracting rising interest as an alternative to conventional rigid structural adhesives. This is due to several benefits such as the excellent impact resistance they provide. This paper investigates experimentally the mechanical behavior of one-component polyurethane adhesive joints and specifically the effect of the adhesive layer to be used in several parts for buses structure. Furthermore, it characterizes the fracture behavior of the adhesive layer with various bond's thicknesses using mode-I and mode-II fracture testing. The fracture toughness under both modes is determined using Double Cantilever Beam (DCB) and End-Notched Flexure (ENF) tests, respectively. Assessment of the various fracture tests indicated that DCB and ENF provide the same shape of evolution of the fracture energy versus adhesive thickness. Moreover, the test results were able to fully mechanically characterize the adhesive and demonstrate that the adhesive has not only high mechanical strength but there is an optimal adhesive thickness, which allows a high toughness for bonded joints. This result proves that it is worthy to use the one-component polyurethane adhesive in the automotive industry.