Evaluation of adhesively bonded joint strength of CFRP with laser treatment

Abstract

Pulsed laser surface treatment was applied to carbon fiber-reinforced plastics (CFRPs) to enhance the work efficiency as well as to establish the stable clean process of surface pre-treatment during the bonding process of CFRP structures. Surface analyses were conducted to CFRP treated by various laser conditions in order to find the optimal laser process. Adhesively bonded specimens were fabricated using CFRPs subjected to laser treatment, and adhesive lap shear strength of CFRPs bonded with adhesive films was evaluated compared with the abrasive paper treatment. Surface conditions, adhesive strength, and adhesive fracture mode depended on the treatment parameters, and adhesive strength similar to abrasive paper treatment could be obtained in the specimens with appropriate laser treatment. It was concluded that laser surface treatment can be applied to the surface treatment process of CFRP bonded structures.

Laser surface treatment of CFRP composites for a better adhesive bonding owing to the mechanical interlocking mechanism

“…In order to improve the efficiency of the surface preparation process for adhesive bonding of CFRP composites, laser ablation method has been evaluated with these advantages . Many researchers have studied laser ablation of CFRP composites . Kreling et al studied the analytical characterization of CFRPs that was laser treated by excimer laser radiation with SEM and XPS.…”

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

“…However, plasma processing usually provides little or no modification of surface morphology and does not enable mechanical interlocking of the bonding substrates [13]. Pulsed laser irradiation recently gained a lot of attention because it is a fast and controllable technique, which can simultaneously modify surface chemistry and morphology, and is suitable for large-scale applications [10,12,21,16,22,23]. In particular, laser beams can be used to selectively remove target materials, including potential contaminants.…”

“…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.…”

“…As a consequence, these surfaces lead to very different fracture responses. 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].…”

A statistical optimization of a green laser‐assisted ablation process towards automatic bonded repairs of CFRP composites

“…The higher the pulse duration and the ED, the larger the HAZ. Single‐lap shear tests were performed by Yokozeki et al , who used a pulsed CO 2 laser (ML105E, wavelength: 10.6 μm, maximum energy: 6.5 J/pulse, pulse frequency: 50 Hz, maximum power: 250 W) for the surface pre‐treatment of the CFRP specimens. They found that the treated with laser specimens had similar shear strength as the manually gridded and much higher than the untreated specimens.…”