Final Thesis

Transfer path analysis in Ultrasonic Metal Welding based on experimental data and simulations

Master Thesis of Liu, Tong

Ultrasonic metal welding (USMW) is a kind of solid-state bonding technique for connecting similar or dissimilar metals using extremely fast frequency oscillations (ultrasonic frequencies). However the details of vibration during the USMW are still unclear in this study field. In this work, 27 groups of measurement on the oscillation of the sonotrode and anvil vibrations along the direction of USMW between two copper layer sheets have been recorded by Laser Doppler vibrometers (LDV). Based on the recorded integrated data sets, firstly, the magnitude ratio and phase shift between the anvil and sonotrode around 20 kHz have been firstly analyzed. Then, the 27 groups of filtered measurement data sets has been fitted into the mass-springdamper model for different stages of USMW according to the empirical phase model from Balz’s dissertation. Finally, the relevant Spring coefficient k and damping coefficient c have been studied at different welding states over the welding time.