Acoustic radiator affecting bubble-acoustic interaction in ultrasonic wave-assisted UWW

Significance 

Technological advances in the field of offshore engineering have led to the development of efficient underwater wet welding techniques suitable for desired applications such as marine mining construction. Considering the current trends in service conditions and materials diversity, the demand for highly efficient and quality underwater wet welding has increased. Unfortunately, their stability is affected by a number of factors that results in poor performance. For instance, the difference in density between the surrounding water and bubble leads to a constant change in the bubble shape, size and motion.

To this note, recent studies have indicated that understanding of the fundamental behaviors of the bubbles would be a key contribution towards enhancing the underwater wet welding processes. However, regardless of the great steps taken in stabilizing the bubbles to achieve high-quality welds, the effects of bubbles dynamic features under the acoustic field is still missing.

In a recently published literature, the use of ultrasonic waves has been extended to welding process technologies. Presently, ultrasonic wave-assisted arc welding has been widely applied in power ultrasound hence leading to the improvement in arc stability, the microstructure and mechanical properties. Alternatively, the differences between heat-induced bubbles and gas bubbles in terms of their generation, formation, and size, result in a corresponding difference in the dynamic behavior characteristics. However, mechanisms of heat-induced bubble under the acoustic field have not been fully explored up to date.

Recently, researchers at Harbin Institute of Technology: Jianfeng Wang (PhD candidate), Professor Qingjie Sun, Jiangkun Ma, Junbo Teng, Peng Jin, Professor Jicai Feng all from the State Key Laboratory of Advanced Welding and Joining investigated the effects of curvature radius on the bubble-acoustic interaction in the ultrasonic wave assisted underwater wet welding. In particular, they designed a concave based acoustic radiator from which they examined the process of bubbles evolution in various curvature radii. Their work is currently published in the research journal, Journal of Manufacturing Processes.

Briefly, the research team commenced in their work by cross-examining the factors affecting the variation of bubble evolution processes including curvature radii, welding current, and arc voltage. Next, improvements in the arc stability, as well as the weld morphology, were determined through welding electrical signals analysis and weld cross-section geometries. Eventually, the significance in changing curvature radii in improving the bubble-acoustic interaction was investigated by simulating the acoustic field in conjunction with the acoustic radiation force measurements.

The authors observed that the ultrasonic wave was capable of stabilizing the bubble surrounding the weld at a constant profile. In addition, different curvature radii resulted in different bubble shapes and motion track. Consequently, the arc stability significantly improved due to the addition of acoustic radiator with varying curvature radii. Furthermore, the similarities in the acoustic simulation results and experimental results indicated the feasibility of the study.

In a nutshell, Harbin Institute of Technology scientists successfully developed an acoustic radiator thereby determining the effects of curvature radii on the bubble-acoustic interaction. In general, the variation in bubble dynamic behaviors resulted in a corresponding improvement in the welding process due to enhanced interaction performance. As such, the study will advance different marine applications. Also, it provides a reference for future work thus will pave the way for more technological advancement in the related fields.

Acoustic radiator affecting bubble-acoustic interaction in ultrasonic wave-assisted UWW - Advances in Engineering
Fig. 1 Schematic of ultrasonic control of arc bubble in underwater wet welding.
Acoustic radiator affecting bubble-acoustic interaction in ultrasonic wave-assisted UWW - Advances in Engineering
Fig. 2 Bubble evolution process in (a) Conventional UWW and (b) U-UWW.

About the author

Qingjie Sun is a full professor of welding technology and engineering, Harbin Institute of Technology (HIT) at Weihai. He received his BS (2003), MS (2006) and PhD (2010) in materials processing from HIT, China. He holds more than 20 patents and 1 coauthored Book.

His current research interests include high efficient automatic welding method and equipment, hybrid magnetic field or acoustic field-assisted arc welding, and wire arc additive manufacturing of dissimilar metal. He has authored or coauthored more than 40 peer-reviewed journal papers.

About the author

Jianfeng Wang is currently a Ph.D. student at the State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology (HIT) in P.R. China. He gained his Bachelor degree and Master degree from HIT in 2013 and 2015, respectively.

He has authored/co-authored more than 25 papers in international refereed journals and 8 patents. His current research interests focus on the ultrasonic wave-assisted underwater wet welding.

About the author

Prof. Jicai Feng is a famous expert in the field of welding technology in China. He works as a senior professor in Harbin Institute of Technology. And he is also the president of Chinese Welding Society as well as director of State Key Laboratory of Advanced Welding and Joining of China.

His research areas include brazing, diffusion bonding, friction stir welding, underwater welding and space welding.

Reference

Wang, J., Sun, Q., Ma, J., Teng, J., Jin, P., & Feng, J. (2019). Investigation of acoustic radiator affecting bubble-acoustic interaction in ultrasonic wave-assisted UWW at shallow water. Journal of Manufacturing Processes, 37, 563-577.

Go To Journal of Manufacturing Processes

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