Analysis of void formation in thermoplastic composites during resistance welding

Shi, Hongbo; Villegas, Irene Fernández; Bersee, H.E.N.

doi:10.1177/0892705716662514

Cited by 37 publications

(17 citation statements)

References 39 publications

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“…This sequential behavior can be explained by the combination of two different mechanisms [4] of deconsolidation and void generation. First, prior to melting, the moisture content in the polymer induces vapor voids.…”

Section: W Welding T Elding Tool Oolmentioning

confidence: 99%

Experimental investigation and optimization of thermal gradients by infrared welding

Perrin¹,

Senoussaoui²,

Dubief³

et al. 2021

Esaform 2021

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Infrared welding technology is currently used in the automotive industry to assemble very complex composite shapes made of short glass fiber reinforced polymers. Such applications are targeted more towards short joining times than towards the optimization of adhesive properties. Through this work, the authors joined their efforts on the experimental investigation of driving mechanisms and their optimization, enabling the welding of high-performance materials typically selected for aeronautics applications. The thermal field through the thickness and on the surface was investigated. The best configuration of the LM-PAEK/C laminate presented a single lap shear (SLS) strength of 43.5 MPa with a standard deviation of 0.7 MPa compared to a strength of 24.9 MPa with a standard deviation of 2.3 MPa obtained with the welding configuration without insulation. These results highlight the major effect of a thermal gradient during infrared welding. It is specific to infrared welding to observe that the major resulting defects are located not at the interface area but inside the composite substrate, where voids, generated during the heating step, are unable to be reconsolidated during pressure application. The impact of the decompaction behavior on the thermal gradient was studied through a MATLAB© implemented 1D numerical model, developed internally and called “LysIR”.

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Section: W Welding T Elding Tool Oolmentioning

confidence: 99%

Experimental investigation and optimization of thermal gradients by infrared welding

Perrin¹,

Senoussaoui²,

Dubief³

et al. 2021

Esaform 2021

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“…Prolonged or over heating leads to polymer degradation and promotes undesirable fiber motions due to excessive melting, whereas too much clamping pressure cause expulsion of melted polymer from the interface. On the other hand, increasing the applied pressure minimizes the process induced voids, mainly those caused by fiber de-compaction [ 156 ]. Nevertheless, experimental results obtained by Howie et al [ 99 ] showed an inverse relationship between the lap shear strength and the bondline thickness, which is significantly affected by the applied pressure.…”

Section: Tpc Joining and Repair Techniquesmentioning

confidence: 99%

Section: Resistance Heatingmentioning

confidence: 99%

Thermoplastic Composites and Their Promising Applications in Joining and Repair Composites Structures: A Review

2020

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Thermoset fiber reinforced composites, widely used in current structural applications, have complex repair procedures and generates significant amounts of scrap due to its recycling difficulties, which does not comply with the most recent environmental restrictions. These disadvantages may be overcome by using a thermoplastic matrix phase, which is very suitable to be joined and repaired by local melting, making the composite material fully recyclable. This work presents a literature review on the joining methods applicable to thermoplastic based composites and their potential applications to be used as repair procedures in structural elements. The effectiveness of selected adhesive and fusion bonding techniques for several thermoplastic composite systems is evaluated by a comparative study based on the joints’ strength and toughness results available in the literature. This work focuses on the three most promising fusion bonding techniques: Resistance welding, induction welding, and ultrasonic welding. The advantages and drawbacks for each one of these processes are discussed, as well as their suitability for several specific structural applications. In addition, several discordant aspects for each welding technique are identified and the corresponding recommendations are discussed. A compilation of analytical models for the mechanisms of heat generation and transient heat transfer modelling is also presented for each fusion bonding process in order to promote their application in numerical modelling.

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“…10,11 Non-uniform heat distribution limits the size of the weld area and introduces defects in weld joints such as voids. 12 Studies have achieved higher values with PEI/CF, because the fiberglass (GF) obtains lower adhesion than the HE/matrix interface. 10,11…”

Section: Introductionmentioning

confidence: 99%

Interfacial, mechanical, and thermal behavior of PEI/glass fiber welded joints influenced by hygrothermal conditioning

Marques

Reis

Abrahão

et al. 2021

Journal of Composite Materials

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This work aims to characterize the influence of hygrothermal conditioning on the mechanical and thermal behavior as well as the fractographic aspects of the interface of poly(ether imide) and glass fiber composite joints welded by electrical resistance using 400 mesh of AISI 304 stainless steel. The composites were mechanically characterized by Lap Shear Strength (LSS) and End Notched Flexure (ENF) testing to investigate maximum shear stress and energy from mode II interlaminar fracture toughness. Fractography was performed by SEM, while the influence on glass transition temperature and working temperature were evaluated by Dynamic-Mechanical Analysis and thermogravimetry. In the conditioned samples, the mechanical properties reduced 23% in the LSS test and 28% in the ENF test, while the fractography studies revealed elements of interlaminar and intralaminar fracture in both conditions. Thermal properties did not change significantly to disqualify this composite when applied to welding.

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Analysis of void formation in thermoplastic composites during resistance welding

Cited by 37 publications

References 39 publications

Experimental investigation and optimization of thermal gradients by infrared welding

Experimental investigation and optimization of thermal gradients by infrared welding

Thermoplastic Composites and Their Promising Applications in Joining and Repair Composites Structures: A Review

Interfacial, mechanical, and thermal behavior of PEI/glass fiber welded joints influenced by hygrothermal conditioning

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