Vibration Analysis of an Ultrasonic-assisted Joining System

Abstract

In the field of lightweight construction, the bonding of multi-material components is an emerging topic. Strong bonds of different materials and material combinations are necessary and in the focus of research [1–3]. Within the German federal cluster of excellence MERGE (Merge Technologies for Multifunctional Lightweight Structures), ultrasonic-assisted joining of lightweight materials such as polymers, light metals and fibre composites is investigated. By support of mechanical pressure, strong bonds can be achieved by ultrasonic-assisted joining, being a suitable technology for adhesive bonding of various materials and material combinations. For these investigations, a modular ultrasonic-assisted joining system was designed which allows different arrangements concerning force and vibration directions.One of the main components of the system is the sonotrode which is the part for coupling energy into the work pieces. The shape of the contact zone between sonotrode and material is crucial for joining, because it defines size and shape of the joining area. The sonotrode geometry is modified to match the joining requirements, but this shifts the resonance frequency and changes the vibration mode. In this work, the influence of different sonotrode geometries onto resonance frequencies and vibration modes was evaluated. By FEM (finite element method) simulations various vibration analyses were conducted and compared to the damped natural frequencies of selected geometries which were measured by single-point laser vibrometer.