The Simulation of the Dynamic Characteristics of Friction Stir Welding and the Structural Deflection of Base Materials

Round 1

Reviewer 1 Report

Reviewer comments to the authors :

In this study, FSW implemented the fabrication of a power converter in a simulated environment to facilitate efficient process development. By performing structural/dynamic analysis, structural deflection data of the cover was recorded, depending on the load of the welding tool. In addition, as a result of sample welding at several selected points, the structural deflection of the base material was confirmed. Based on the data obtained here, a factor depending on the dynamic characteristics of the welding tool was selected and the sample welding process was carried out.

1.    The abstract section is written more like an introduction. The abstract needs to discuss the purpose of the study, the methods utilized and the results of the study.

2.    The introduction section should provide the current status of recent research on the FVM model for friction stir welding.

3.    The conclusion section should not be overly concerned with describing the process.

4.    The article reads more like a report and needs to be analyzed in more depth.

5.    What software is used to implement the finite element method? What is the software for the finite volume method? The number and quality of meshes need to be reflected in the article.

6.    Does the variation in the number of meshes have any effect on the accuracy of the displacement values of the cover simulation?

7.    How can the accuracy of the numerical simulation be verified? This paper only gives the experimental results of one dynamic factor, and does not give the comparison of experimental results of other dynamic influences. It only shows that the numerical simulation can describe the variation trend, but it does not prove the accuracy and reliability of the model built.

Author Response

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Reviewer 2 Report

In the work, FSW for manufacturing power converters in a simulation environment to facilitate efficient process development was studied. The structural characteristics were confirmed with respect to the load, progress velocity, and rotational velocity of the welding tool, as well as the velocity distribution around the softened base material. The current work is interesting and inspiring. It is helpful for further advancing the technique. It is suggested that the manuscript be accepted after the following minor comments are taken care of.

1.      Sound and concise conclusions and abstract with the supporting results should be given to the reader. Mention the significant findings with values. And the academic language should be refined by proof-read carefully.

2.      The authors claimed that FSW is attracting attention as a next generation welding technology from various industrial fields because material deformation due to FSW is small, and the mechanical properties of the weld, such as tensile strength and yield strength, are superior [2–4]. FSW, a mature solid-state welding technique, involves temperature, mechanics, metallurgy and interactions, has become a revolutionary welding technique. To broaden the adoption of FSW in manufacturing fields, three inherent issues—back support, weld thinning and keyhole defects—should be addressed to ensure the structural integrity, safety and service life of the manufactured products[https://doi.org/10.1016/j.pmatsci.2020.100706]. The lower heat input results in better mechanical properties, and less possibility of distortions in the part and in the welded region.

3.      In the work, a welding process post softening of the base material is implemented through simulation. The results obtained depending on the rotation and progress velocity of the welding tool are compared and analyzed. The entire-process simulation of friction stir welding based on experiment validation was adopted for the prediction of tensile strength. This included the computational fluid dynamics model, precipitation evolution model, dynamic recrystallization and recovery model, and computational solid mechanics model reported as https://doi.org/10.29391/2022.101.011 and https://doi.org/10.29391/2022.101.013. A fluid-solid-interaction algorithm was proposed to establish the coupling model, and the material to be welded was treated as non-Newtonian fluid [https://doi.org/10.1016/j.jmst.2019.01.016]. High-throughput screening method, based on the marriage between massively parallel computational methods and existing database containing the calculated properties, is capable to explore hypothetical candidates [https://doi.org/10.1016/j.jmatprotec.2017.09.029], and the amelioration via the material flow model inhibits the welding defects and optimizes the parameter intervals, providing references to extracting process-structure-property linkages for FSW.

4.      In the dynamic system model, how consider the tool? The material flow was affected by the temperature and the profile of tool. Is it possible to consider the tool structure for the model? And more detail explanation to the experiment and tool design should be described and given to help readers to understand the processing and analysis.

Author Response

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Author Response File: Author Response.pdf