Ultrasonic Welding of Novel Carbon/ Elium® Thermoplastic Composites with Flat and Integrated Energy Directors: Lap Shear Characterisation and Fractographic Investigation.

Somen K Bhudolia,Kah Fai Leong,Jayaram Kantipudi,Goram Gohel,Robert J Barsotti

doi:10.3390/ma13071634

Somen K Bhudolia, Kah Fai Leong + Show 3 more

Open Access

https://doi.org/10.3390/ma13071634

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Journal: Materials	Publication Date: Apr 1, 2020
Citations: 28	License type: CC BY 4.0

Affiliation: Nanyang Technological University, Arkema (France)

Abstract

The current research work presents a first attempt to investigate the welding attributes of Elium® thermoplastic resin and the fusion bonding using ultrafast ultrasonic welding technique. The integrated energy director (ED) polymer-matrix composites (PMCs) panel manufacturing was carried out using the Resin Transfer Moulding (RTM) technique and the scheme is deduced to manufacture a bubble-free panel. Integrated ED configurations and flat specimens with Elium® film of different thickness at the interface were investigated for ultrasonic welding optimization. Optimised weld time for integrated ED and flat Elium® panels with film (0.5 mm thick) configuration was found to be 1 s and 5.5 s, respectively. The ED integrated configuration showed the best welding results with a lap shear strength of 18.68 MPa. The morphological assessment has shown significant plastic deformation of Elium® resin and the shear cusps formation, which enhances the welding strength. This research has the potential to open up an excellent and automated way of joining Elium® composite parts in automotive, wind turbines, sports, and many other industrial applications.

Highlights

Thermoplastic (TP) composites are mostly preferred in different manufacturing industries, due to their excellent damping, impact, fracture toughness, recyclability properties, and its ability to be fused or welded to itself or with other materials [1,2]
This study showed that the welding quality increases with the increase in time from 0.7 s to 0.8 s, but further at higher welding time (1.1 s) large cracks and voids are formed at the interface; 0.9 s was found to be the optimum time for good weld quality
An experimental study showing the influence of different welding parameters, such as weld time, weld pressure, amplitude, energy director (ED) type, and others on the weld strength, were investigated

Summary

Introduction

Thermoplastic (TP) composites are mostly preferred in different manufacturing industries, due to their excellent damping, impact, fracture toughness, recyclability properties, and its ability to be fused or welded to itself or with other materials [1,2]. Thermoplastic resin has the ability to soften once heated above the defined temperature range and retain its properties once it is cooled down. There is a growing call from the wide spectrum of industries (aerospace, automotive, sports, and many more) to eradicate the classical ways of joining the polymer composite parts, namely mechanical fastening and the use of control adhesives. The major drawback of using the former is that, due to the holes and cutouts in the composites, they are susceptible to high-stress concentration and it is labour intensive, whilst the latter requires an incredibly longer curing time as well as the longer surface preparation [3,4]. The welding attributes of thermoplastics aids the cost-effectiveness of the composite

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