Journal of Applied Mechanical Engineering

Efficient modeling of ultrasonic welding of composite through a time homogenization framework

International Conference on Design and Production Engineering

July 25-26, 2016 Berlin,Germany

Steven Le Corre

University of Nantes, France

Posters & Accepted Abstracts: J Appl Mech Eng

Abstract:

Among the different welding techniques for thermoplastic materials, ultrasonic welding is of particular interest because of its energy efficiency and rapidity. In this process, triangular �??energy directors�?�, are molded on one of the plates to be welded. The assembly is then placed under a tool called sonotrode, which applies simultaneously a constant load and a harmonic ultrasonic compression. The triangular shape, the weakest part, concentrates the deformation and induces heating because of the high viscous dissipation at those frequencies (20 kHz). The director then melts and flows at the interface and the welding can be obtained. Like in every welding process, the modeling of the ultrasonic technique is a complex multi-physical problem but the unique feature of this process is that the high frequency of the loading makes any direct calculation unaffordable. To circumvent this problem, a time-homogenization technique was proposed by Levy et al. that provides a mathematically basis for such type of problem. It takes advantage of the good time scales separation between the welding time (1 s) and the period of the ultrasonic vibration (50 μs). The homogenization method enables to transform the initial coupled thermo-mechanical problem into three problems, where the short time-scale can be solved separately from the long time-scale. In this work, two applications of this type of modeling are presented for the simulation of US welding: one in the case of an energy director based technique and another one in the case of a recently proposed energy director free approach.

Biography :

Email: steven.lecorre@univ-nantes.fr