Research On Dynamic Evolution Of Bubbles In Underwater Welding Based On Acoustic Signal Detection

With the increasing number of deep-sea development projects,various major underwater engineering projects are closely connected with underwater welding technology.Underwater wet flux cored wire welding(FCAW)occupies an important position in the maintenance of underwater marine facilities due to its advantages of good operability,low cost,and strong applicability.The combustion of the arc is carried out in dynamically changing bubbles around the welding area,and the growth of the bubbles will affect the stability of the welding arc.This paper is based on the detection of bubble acoustic pulse signals,simulates different water depth pressures,and conducts underwater wet welding experiments.The experimental platform collects bubble sound signals,arc electric signals and bubble images in different welding states for related analysis.The main research contents completed include:(1)An underwater wet welding high-pressure simulation experiment cabin was built.The experiment cabin is composed of a pressurization and safety system,a welding system and a collection system.A synchronous acquisition system was used to synchronously acquire the arc current voltage signal,the bubble sound signal and the bubble image during the welding process,and test the arc burning state under different welding parameters.(2)The original signal collected was subjected to noise reduction processing,the time domain and frequency domain characteristics of the arc electrical signal and the bubble acoustic signal were studied,and the correlation analysis of each signal and the arc stability was carried out by statistical analysis..(3)In the underwater wet welding process,the behavior of the bubbles has an important influence on the combustion of the arc.By observing the high-speed camera shooting bubble images at each stage of combustion,the relationship between the bubble shape,evolution process and bubble acoustic signal during the wet welding process was studied.Combined with the above analysis,the bubble image,bubble acoustic signal and arc current voltage signal captured by high-speed camera were used to analyze the arc characteristics of underwater wet welding,and the effect of bubbles on arc combustion was studied from the perspective of acoustic signal.The research shows that there is a clear realtime correlation between the bubble acoustic signal and the arc electrical signal.The change of the bubble acoustic signal can reflect the stable state and characteristics of the underwater wet arc welding.This verifies that it is feasible to analyze the stability of arc combustion under the influence of different bubble dynamic behaviors through bubble acoustic signals.