On the effect of flat energy directors thickness on heat generation during ultrasonic welding of thermoplastic composites

Journal article (2017)

Authors

G. Palardy Structural Integrity & Composites - Aerospace Engineering
I.F. Villegas Structural Integrity & Composites - Aerospace Engineering
Research Group
Structural Integrity & Composites (Aerospace Engineering) (TU Delft)
Copyright: © 2017 G. Palardy, I.F. Villegas
DOI
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https://doi.org/10.1080/09276440.2016.1199149
Mechanical properties Thermoplastic composites Energy directors Optical microscopy Plastic ultrasonic welding
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Published Date

12-02-2017

Language

English

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Faculty

Aerospace Engineering

Department

Aerospace Structures & Materials

Research Group

Structural Integrity & Composites

Abstract

This paper presents a detailed experimental assessment of the effect of the thickness of flat energy directors (ED) on heat generation at the interface during ultrasonic welding. Power and displacement data showed clear differences caused by the change of thickness, related to heat concentration at the weld line during the process. The extent of the heat-affected zone was assessed by welding specimens without consolidation at different stages of the process. It was confirmed through optical microscopy that heat is generated at the interface and transferred to the bulk adherends earlier in the process for thinner ED. The analysis of their fracture surface under optimum welding conditions revealed signs of matrix degradation, leading to less consistent quality, likely due to faster heat generation rate in both the ED and the substrates, and incidentally, higher temperatures surrounding the energy director.