title: Frictional effect of ultrasonic-vibration on upsetting.
abstract: The ultrasonic-vibration ring compression test and finite element analysis were performed on aluminum alloy specimens to explore the frictional effect of superimposing ultrasonic-vibration during upsetting. The extrapolated compression test was first adopted to obtain the frictionless material properties for finite element analysis. Experimental results of extrapolated compression test also indicate that ultrasonic-vibration can reduce the compressive force when friction is eliminated and can increase the temperatures of a material at the same time. The following results of the hot extrapolated compression test and the hot ring compression test reveal that increasing temperature by ultrasonic-vibration may reduce the flow stress and increase the interfacial friction. Finally, finite element analysis was conducted to derive the friction calibration curves and to evaluate the friction factor.
authors.affiliation: Department of Mechanical Engineering, National Chin-Yi Institute of Technology, Taiwan, ROC.
authors.forename: Jung-Chung
authors.initials: JC
authors.lastname: Hung
authors.forename: Yu-Chung
authors.initials: YC
authors.lastname: Tsai
authors.forename: Chinghua
authors.initials: C
authors.lastname: Hung