Improvement of bonding strength of scarf-bonded carbon fibre/epoxy laminates by Nd:YAG laser surface activation

Schmutzler, Henrik; Popp, Jan; Büchter, Edwin; Wittich, H.; Schulte, Karl; Fiedler, Bodo

doi:10.1016/j.compositesa.2014.08.029

Cited by 31 publications

(10 citation statements)

References 18 publications

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“…However, in literature, there are a limited number of papers on laser surface treatment of composite materials. Many of them concern the use of CO 2 , Nd:YAG or UV laser source, while no studies on the use of Yb:YAG fiber laser are reported, even more so on Carbon Fiber Reinforced Thermoplastic Polymers.…”

Section: Introductionmentioning

confidence: 99%

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Increasing adhesive bonding of carbon fiber reinforced thermoplastic matrix by laser surface treatment

Genna

Leone

Ucciardello

et al. 2017

Polymer Engineering & Sci

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In this study, laser surface treatment of CFRP made of PPS thermoplastic matrix by means of Q-switched Yb:YAG fiber laser is investigated with the aim to improve CFRP adhesive bonding. Two set of experimental tests were developed. In the first, laser treatments were executed fixing the average power (Pa) and changing: the pulse power, the scanning speed, the hatch distance, and the scanning strategy. These tests were performed to individuate the laser-material interaction mechanisms and the process window. The treated surfaces were investigated using optical microscopy. It was found that the treatment is able to remove the outer layer of the matrix up to the exposure of underlying reinforcement. However, depending to the released energy, incomplete cleaning or excessive damage may occur. Then, the operating window was experimentally determined. In the second experimental tests, single lap shear tests were performed on samples treated under the most promising process conditions, to verify the laser treatment effectiveness. It was found that the laser treatment, compared to the untreated samples, is able to increase the apparent shear strength up to three times

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Section: Introductionmentioning

confidence: 99%

“…In latter cases, the treatment aim is to completely remove the outer layer of the matrix up to the exposure of underlying reinforcement. Therefore, the mechanism of interaction is mainly of heating or thermal ablation and may produce HAZ . From the above, it might seem that an UV source is the best solution to avoid HAZ.…”

Section: Introductionmentioning

confidence: 99%

Increasing adhesive bonding of carbon fiber reinforced thermoplastic matrix by laser surface treatment

Genna

Leone

Ucciardello

et al. 2017

Polymer Engineering & Sci

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“…Replacement poses, in many cases, not the most economic option . In this context, bonded repairs offer distinct advantages in comparison to mechanically fastened repairs, such as a beneficial stress distribution, surface smoothness, and weight reduction . In addition to the merits of bonding, Katnam et al .…”

Section: Introductionmentioning

confidence: 99%

Bonded aerospace repairs under tensile loading: Wet chemical surface treatment and selected environmental conditions

Röper

Wolfahrt

Schlögl

et al. 2019

J of Applied Polymer Sci

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Repair of composite structures and the impact of demanding environmental conditions is a crucial issue for the aircraft industry because of the increasing use of composites in modern aircraft. Consequently, the impact of environmental conditions common for aircraft applications on repair specimens in comparison to nonrepaired specimens is studied. All specimens are produced from a woven carbon fiber‐reinforced epoxy‐based prepreg. For the repair‐specimens, an epoxy‐based film adhesive is used for the soft patch repair approach. During the repair process, the surface of the precured prepreg is prepared by a mechanical method (sanding) and an additional chemical functionalization, respectively. Moisture absorption of the repair specimens is independent of the surface preparation method and higher for the repaired than for the nonrepaired specimens. The key influencing environmental conditions for the tensile strength and the failure mode of the repair specimens are elevated temperature testing as well as hot/wet conditioning and conditioning in deionized water. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47506.

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“…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 ]. Palmieri found that a 355 nm Nd:YAG laser could ablate about 10–20 µm depth of the laminate surface without breaking fibres and will improve the reproducibility and robustness in a production environment [ 39 ].…”

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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Improvement of bonding strength of scarf-bonded carbon fibre/epoxy laminates by Nd:YAG laser surface activation

Cited by 31 publications

References 18 publications

Increasing adhesive bonding of carbon fiber reinforced thermoplastic matrix by laser surface treatment

Increasing adhesive bonding of carbon fiber reinforced thermoplastic matrix by laser surface treatment

Bonded aerospace repairs under tensile loading: Wet chemical surface treatment and selected environmental conditions

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

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