Mechanical analysis of ultrasonic welding considering knurl pattern of sonotrode tip

Finite element analysis of heat generation in dissimilar alloy ultrasonic welding

“…The literature summarised in Table 1 shows that the prime objectives of all thermomechanical modelling are to predict the temperature history and heat generation as a function of process conditions, and in many cases the evolution of the state and shape of the deformation zone, and development of the full bond -though experimental validation is not always provided. Knowledge of the process conditions is then applied to interpret or predict other aspects of the process -for example: (i) an indication of the joint strength [11] or fracture energy [12,13]; (ii) the effect of the sonotrode knurl pattern on interface deformation and bond formation [21][22][23][24][25]; and (iii) grain size and microhardness in the weld zone [26].…”

“…Nonetheless, most of the previous approaches to modelling USW still lack computational efficiency, by attempting to model the 1000s of cycles taken, due to the very high frequency of the process. Several authors comment on this problem, and adapt their implementation to improve computational efficiency -for example, using explicit analysis to predict the frictional heat flux, which then served as an input to an implicit analysis of the entire process [20], and the common techniques of limiting the model size and grading the mesh [22][23][24][25], or simplifying to 2D [21]. Some authors have sought computational efficiency by making simplifications that avoid the challenges of high frequency and thermomechanical coupling completely, while capturing some of the essential mechanical chacateristics.…”

“…As a footnote to the analysis, attention is turned briefly to the effect of tool alignment, which has received little attention in the literature. An important element of the USW process is the knurling of the tool tip, which has been shown to have significant influence on the in-process variables [22][23][24][25]. Chen et al [5] found that at long welding times and significant tool indentations, tool misalignment was observed, and this caused the formation of shear bands, visible on an image of a weld crosssection (Fig.…”

Analysis of the Effect of Ultrasonic Welding on Microstructure

“…It is known that recrystallization principally depends on the heating temperature and the heating time. No high temperature or long retention time was observed in our experi-ments, however, the structure was altered (particle size and grain geometry changed) [6,7].…”

Microstructure and Mechanical Properties of an Ultrasonic Spot-Welded Aluminum-to-Aluminum Joint: Response to Interlayer Thickness

“…Ultrasonic spot welding (USW) as a further spot welding technique has been paid more attention. Chen et al [8] confirmed that USW is a solid phase joining technique and that under the combination effects of high shear frequency vibration and clamping force, two metal sheets can be joined by such a technique. Daniels [9] noted that USW was first introduced for thin foils joining, wire bonding, and tube sealing in the 1950 s. It was used to join thicker metal sheets (such as Al, Cu, NiTi, Fe, and Ni) due to advancements in the welding system technique [10,11,12,13].…”