Thermomechanical analyses of ultrasonic welding process using thermal and acoustic softening effects

Effect of Ultrasonic Vibration on Compression Behavior and Microstructural Characteristics of Commercially Pure Aluminum

“…For this purpose, the change of activation energy (DF) as a key factor during ultrasonic excitation appears in the ratio of flow stress reduction versus mechanical threshold (ŝ). Referring to experimental observations reported by literatures (Ref [18][19][20][21]26), the decrease in flow stress is proportional to the vibration amplitude (or square root of ultrasonic energy density). Hence, the difference in the ratio of flow shear stress (s) to the internal variable (ŝ) between both conditions under ultrasonic vibration (index ''U'') and without vibration (index ''0'') is expressed as…”

Thermal transients during processing of materials by very high power ultrasonic additive manufacturing

“…In other words, this is evidence of plastic deformation heating. The involvement of plastic deformation heating (in addition to frictional heating) in ultrasonic metal welding/UAM has been noted earlier, in the works of Yadav (2001) on 1100 Al, de Vries (2004) and Siddiq and Ghassemieh (2008) on 6061 Al, and Zhang and Li (2009) on 3003 Al, but mainly through modeling. This has also been mentioned in the research of Mariani and Ghassemieh (2010) on 6061 Al.…”

Role of friction on the thermal development in ultrasonically consolidated aluminum foils and composites

“…Thus variations in the friction coefficient observed by Naidu and Raman (2005) as a function of cyclic stress can be similarly related to changes in . This approach is taken by Siddiq and Ghassemieh's (2008) in their UC study to determine as a function of weld amplitude, . The third input parameter, weld speed, s, is inversely proportional to N, the number of cycles as shown in Eq.…”