A comparison of IR- and UV-laser pretreatment to increase the bonding strength of adhesively joined aluminum/CFRP components

Reitz, Valentina; Meinhard, Dieter; Ruck, Simon; Riegel, Harald; Knoblauch, Volker

doi:10.1016/j.compositesa.2017.02.014

Cited by 95 publications

(47 citation statements)

References 24 publications

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“…In fact, by laser cleaning the surface of the sample, a rougher surface is obtained, therefore improving the joining between the materials. This is in accordance with the pertinent literature [17,42], in which it is stated that the combination of the surface activation without affection of the integrity of the laminate due to the cleaning of the surface leads to the strengthening of the joint. However, it is worth to note that using the highest power level, i.e., 200 W, involves the adoption of a higher scan speed in order to keep constant the laser energy.…”

Section: Resultssupporting

confidence: 92%

Combined Fuzzy and Genetic Algorithm for the Optimisation of Hybrid Composite-Polymer Joints Obtained by Two-Step Laser Joining Process

et al. 2020

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In the present work, genetic algorithms and fuzzy logic were combined to model and optimise the shear strength of hybrid composite-polymer joints obtained by two step laser joining process. The first step of the process consists of a surface treatment (cleaning) of the carbon fibre-reinforced polymer (CFRP) laminate, by way of a 30 W nanosecond laser. This phase allows removing the first matrix layer from the CFRP and was performed under fixed process parameters condition. In the second step, a diode laser was adopted to join the CFRP to polycarbonate (PC) sheet by laser-assisted direct joining (LADJ). The experimentation was performed adopting an experimental plan developed according to the design of experiment (DOE) methodology, changing the laser power and the laser energy. In order to verify the cleaning effect, untreated laminated were also joined and tested adopting the same process conditions. Analysis of variance (ANOVA) was adopted to detect the statistical influence of the process parameters. Results showed that both the laser treatment and the process parameters strongly influence the joint performances. Then, an uncertain model based on the combination of fuzzy logic and genetic algorithms was developed and adopted to find the best process parameters’ set able to give the maximum joint strength against the lowest uncertainty level. This type of approach is especially useful to provide information about how much the precision of the model and the process varies by changing the process parameters.

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Section: Resultssupporting

confidence: 92%

Combined Fuzzy and Genetic Algorithm for the Optimisation of Hybrid Composite-Polymer Joints Obtained by Two-Step Laser Joining Process

et al. 2020

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“…Currently, there is no universally defined tool for laser ablation; indeed, pulsed laser systems operate at different pulse regimes with wavelengths varying from UV to IR, which causes different interactions with the target material. For applications on CFRPs, previous works focused on excimer (λ = 308 nm) [12,21], Nd-YAG (λ = nm) [16,18], fiber lasers (near-IR range, λ = 1064 nm) [24] and CO 2 lasers (mid-IR range, λ = 10.6 µm) [9,23,25]. The different laser-CFRP interactions that can be realized lead to large variations in the treated surfaces, from a simple surface "cleaning", with little or no modification of surface layers, to a full removal of the matrix with consequent exposure of carbon fibers.…”

Section: Introductionmentioning

confidence: 99%

“…Compared to UV lasers, CO 2 laser has higher processing speed and larger processing area, which is suitable for industrial applications [23]. Besides, fiber lasers input larger amount of heat into carbon fibers, resulting in near surface substrate damage such as the fiber/matrix debonding [9,25].…”

Section: Introductionmentioning

confidence: 99%

Laser-based surface patterning of composite plates for improved secondary adhesive bonding

Tao

Alfano

Lubineau

2018

Composites Part A: Applied Science and Manufacturing

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The effects of laser irradiation surface pretreatments on the mode I fracture toughness of adhesively bonded composite joints were evaluated. First, pulsed CO 2 laser irradiation was uniformly deployed on carbon fiber reinforced polymer (CFRP) substrates. Next, double cantilever beam (DCB) tests were performed to assess the effects of surface pretreatments on the mode I fracture toughness of the adhesive joints. Then, a thoughtful combination of the proposed surface pretreatments was deployed to fabricate DCB specimens with patterned interfaces. A wide range of techniques, including X-ray photoelectron spectroscopy (XPS), contact profilometry, and optical and scanning electron microscopy (SEM) were used to ascertain the effects of all investigated surface pretreatments. It is shown that patterning promoted damage mechanisms that were not observed in the uniformly treated interfaces, resulting in an effective fracture toughness well above that predicted by a classical rule of mixture.

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“…Laser-treatment process can provide uniform surface behaviours to ensure high reliability and repeatability for aircraft structural repairs to avoid human errors and inconsistencies. Reitz demonstrated that wavelength and energy input are the critical parameters for laser pre-treatment, and UV-laser system can avoid near surface laminate damage while IR-laser breaks the fibre--matrix [ 37 ]. Henrik used a Nd:YAG laser to study the influence of adhesive properties in a standard SCARF repair process and showed that oxidized fibres can improve the adhesive strength [ 38 ].…”

Section: Introductionmentioning

confidence: 99%

A study of laser surface treatment in bonded repair of composite aircraft structures

Li¹,

Sun²,

Liu³

et al. 2018

R. Soc. open sci.

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Surface pre-treatment is one of the key processes in bonded repair of aircraft carbon fibre reinforced polymer composites. This paper investigates the surface modification of physical and chemical properties by laser ablation and conventional polish treatment techniques. Surface morphology analysed by laser scanning confocal microscopy and scanning electron microscopy showed that a laser-treated surface displayed higher roughness than that of a polish-treated specimen. The laser-treated laminate exhibited more functional groups in the form of O 1 s/C 1 s atomic ratio of 30.89% for laser-treated and 20.14% for polish-treated as evidenced by X-ray photoelectron spectroscopy observation. Contact angle goniometry demonstrated that laser treatment can provide increased surface free energy and wettability. In the light of mechanical interlocking, molecular bonding and thermodynamics theories on adhesion, laser etching process displayed enhanced bonding performance relative to the polishing surface treatment. These properties resulted in an increased single lap shear strength and a cohesive failure mode for laser etching while an adhesive failure mode occurred in polish-treated specimen.

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A comparison of IR- and UV-laser pretreatment to increase the bonding strength of adhesively joined aluminum/CFRP components

Cited by 95 publications

References 24 publications

Combined Fuzzy and Genetic Algorithm for the Optimisation of Hybrid Composite-Polymer Joints Obtained by Two-Step Laser Joining Process

Combined Fuzzy and Genetic Algorithm for the Optimisation of Hybrid Composite-Polymer Joints Obtained by Two-Step Laser Joining Process

Laser-based surface patterning of composite plates for improved secondary adhesive bonding

A study of laser surface treatment in bonded repair of composite aircraft structures

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