Characterisation of crystallinity at the interface of ultrasonically welded carbon fibre PPS joints

Koutras, N.; Amirdine, Juliana; Boyard, Nicolas; Villegas, Irene Fernández; Benedictus, Rinze

doi:10.1016/j.compositesa.2019.105574

Cited by 40 publications

(17 citation statements)

References 50 publications

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“…Consequently, cooling rates at the weld line can be expected to be significantly lower for a combination of low force and low amplitude during the vibration phase. This was indeed the result obtained by Koutras et al (2018) when investigating the cooling rate and crystallinity at the weld line in ultrasonic welding of CF/PPS composites. Furthermore, the higher cooling rates obtained at high force (1,000 N) and high amplitude (86 µm, peak-to-peak) conditions were found to result in mainly amorphous weld lines.…”

Section: Process Parameterssupporting

confidence: 83%

“…Interestingly it was found that, even though the much slower cooling in the low force (300 N) and low peak-to-amplitude (52 µm, peak-to-peak) conditions was not slow enough to render crystallization according to flash DSC results, the weld lines obtained in those conditions did feature a significant amount of crystallinity (see Figure 4). The FIGURE 4 | Degree of crystallinity at the weld line in CF/PPS single-coupons welded in low force and low amplitude conditions (300 N, 52 µm) and in high force and high amplitude conditions (1,000 N, 86 µm peak-to-peak) as compared to reference values (press consolidated neat PPS) (Koutras et al, 2018).…”

Section: Process Parametersmentioning

confidence: 99%

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Ultrasonic Welding of Thermoplastic Composites

Villegas

2019

Front. Mater.

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Ultrasonic welding is a very fast and energy-efficient technique for the joining of thermoplastic composites. This article looks into main aspects of ultrasonic welding of continuous fiber-reinforced thermoplastic composites, namely energy directors, process parameters, in situ process monitoring, welding of dissimilar composite materials and upscaling routes. From the author's viewpoint these are key topics for deepening our insight into the ultrasonic welding process and, eventually, for enabling its future industrialization.

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Section: Process Parameterssupporting

confidence: 83%

Section: Process Parametersmentioning

confidence: 99%

Ultrasonic Welding of Thermoplastic Composites

Villegas

2019

Front. Mater.

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“…Compared with thermoset composites, thermoplastic composites have an advantage that they can be quickly assembled via fusion bonding techniques. 1,2 As a kind of high-performance engineering thermoplastic composites with outstanding mechanical properties and superior chemical resistance, CF/PEEK composites are widely used in manufacturing industries such as medical 3 and aerospace. 4 However, CF/PEEK composites have many processing restrictions, such as the high melt viscosity of PEEK and the constraint imposed by continuous fiber reinforcement.…”

Section: Introductionmentioning

confidence: 99%

Enhanced adhesion between PEEK and stainless-steel mesh in resistance welding of CF/PEEK composites by various surface treatments

Sun

Song

et al. 2021

High Performance Polymers

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In order to improve the interfacial adhesion of stainless-steel mesh reinforced poly(ether-ether-ketone) (SSM/PEEK) heating elements (HEs) used in the resistance welding process for continuous carbon fiber reinforced PEEK composites (CF/PEEK composites), three kinds of surface treatments, sandblasting, aryl diazonium grafting and silane grafting, were adopted on SSM surfaces. The functional groups were grafted successfully according to the Fourier Transform Infrared (FTIR) results and Energy Dispersive Spectrometer (EDS) results, and the surface morphologies of SSM changed significantly after different treatments. Although the tensile performances of sandblasted stainless-steel (SS) wire and sandblasted SSM were distinctly reduced, the lap shear strength (LSS) of joints with sandblasted SSM still slightly improved. Besides, the interfacial shear strength (IFSS) increased from 28 MPa for untreated SSM to 34 MPa for diazonium grafted SSM and 38 MPa for silane grafted SSM. Furthermore, the LSS results were in agreement with this trend, representing a 9% improvement for joints with diazonium grafted SSM and a 23% improvement for joints with silane grafted SSM compared with untreated CF/PEEK joints. After comparison, silane grafting was the most suitable surface modification for resistance-welded CF/PEEK joints. The interfacial bonding mechanism of CF/PEEK joints with silane grafted SSM was compared with that of untreated CF/PEEK joints, suggesting that the mechanical interlocking contributed to improved interfacial bonding.

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“…In the literature, the use of TCs to measure temperature under the sonotrode during the US process has been reported with some success. [20][21][22] However, it is expected that the vibrations may generate local heating of the TCs, acting as energy directors themselves, which should be taken into account when analyzing data. 10,23 In this study, measurements were carried out on UD (4 and 12 plies) samples.…”

Section: Temperature and Doc Measurementsmentioning

confidence: 99%

High-speed consolidation and repair of carbon fiber/epoxy laminates through ultrasonic vibrations: A feasibility study

Hoskins

Palardy

2020

Journal of Composite Materials

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Ultrasonic welding is a common fusion bonding technique to join unreinforced and reinforced thermoplastics. It is expected that applying ultrasonic vibrations to thermoset prepregs can produce heat generation to promote resin flow and consolidation. This paper discusses the feasibility of using ultrasonic vibrations as a high-speed repair technique for carbon fiber/epoxy prepregs to replace the traditional vacuum-bagging scarf setup. Three material types were investigated: out-of-autoclave unidirectional and plain weave prepregs (Cycom® 5320) and a general purpose twill weave prepreg (AS4/Newport 301). Two welding modes were considered: time and travel (vibrations stop once the desired vertical displacement is reached). For each mode, vibration time, travel, force, and amplitude were investigated. Cross-sectional analysis showed that void content equal to or below the vacuum-bagged samples could be achieved with ultrasonic consolidation to meet aerospace standards (≤2%). The following ultrasonic parameters were recommended to preserve prepreg tows integrity and minimize void content: vibration time below 1.0 s, travel between 12.5% and 50% of sample's initial thickness, force equal to or below 100 N, and amplitude below 41.3 μm. Temperature values recorded during the ultrasonic process reached the manufacturer's cure temperature range (120℃ to 180℃), with a predicted maximum degree of cure of 0.24. Interlaminar shear strength values were comparable for ultrasonically consolidated and vacuum-bagged samples. Soft and hard repair patches were applied to open-hole tensile coupons, with up to 50% strength recovery for both repair methods. Overall, ultrasonic consolidation has potential as a time- and cost-efficient repair method for thermoset prepregs.

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Characterisation of crystallinity at the interface of ultrasonically welded carbon fibre PPS joints

Cited by 40 publications

References 50 publications

Ultrasonic Welding of Thermoplastic Composites

Ultrasonic Welding of Thermoplastic Composites

Enhanced adhesion between PEEK and stainless-steel mesh in resistance welding of CF/PEEK composites by various surface treatments

High-speed consolidation and repair of carbon fiber/epoxy laminates through ultrasonic vibrations: A feasibility study

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