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

Genevieve Palardy, Irene Fernandez Villegas
2016 Composite interfaces (Print)  
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
more » ... oscopy 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.
doi:10.1080/09276440.2016.1199149 fatcat:2vysxmz7sbfcnjcmdyig2svly4