A New Method for Determining Necking of Sheet Metal Based on Main Strain Topography

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Liqiu Shi et al. present a work that uses a method for determining necking in metal sheets. 

A thorough introduction exposes the interest and complexity of accurately characterizing the necking failure. Several methods are explained in detail, and the authors propose a new technique. 

The method is described clearly, and the experiments presented contribute to a better comprehension of the procedure used to analyze this problem. Finally, a comparison is presented, and the advantages and limitations are stated. 

This work's topic is interesting for readers in mechanical engineering. It may provide a tool for better analyzing the evolution of sheets under stress. Thus, I recommend publishing it in Coatings.

 

I would like to provide some recommendations to the authors:

-I suggest removing the term thin in the title since 1.5 mm thick plates do not look thin. What would be 0.1 mm foils?

-I also advise improving and clarifying some figures:

Figure 3: y label should be major strain (I guess)

Figure 4: In panels a and b, there are two regions that lack a clear definition of their significance. It appears as if two sheets are being considered instead of a single sheet (as mentioned on page 5). I found no explanation for this diagram in the caption or the text. Could you provide a clear definition for these regions?  

Figure 5b: Define the meaning of the thick line.

 

Author Response

Thank you for your precious comments and advice. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portion are marked in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

Point 1: I would like to provide some recommendations to the authors:

-I suggest removing the term thin in the title since 1.5 mm thick plates do not look thin. What would be 0.1 mm foils?

Point 2: Figure 3: y label should be major strain (I guess)

Point 3: Figure 4: In panels a and b, there are two regions that lack a clear definition of their significance. It appears as if two sheets are being considered instead of a single sheet (as mentioned on page 5). I found no explanation for this diagram in the caption or the text. Could you provide a clear definition for these regions?

Response 3: Figure 4 shows the strain of the same metal plate at different times during the expansion test. It is commonly believed in the industry that metal plates undergo three stages of dispersive destabilization, aggregative destabilization and fracture during the expansion test. During the expansion test, if there is a stress concentration in the sheet metal in a narrow band, it is considered that the plate enters the aggregated instability stage as shown in Fig. 4b, and before that it is the dispersed instability stage as shown in Fig. 4a.

Point 4: Figure 5b: Define the meaning of the thick line.

Response 4: The trajectory formed at the location of the fastest change in major strain of the sheet metal during the experiment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for the opportunity to review the paper entitled “A new method for determining necking of thin metal sheets based on main strain topography”. The paper is well-written, clear, but in my opinion lacks originality, which I will explain below.

Title and abstract

The title and abstract are both informative and the Reader knows what to expect from the paper.

Introduction

Lines 33 – 37 – the sentence is very long and ambiguous, it would be better to divide it into 2 sentences.

Line 56 – “they” is not necessary

Line 67 – 68 – finite element is not a software, it is a method implemented for calculations by software such as Deform, Ansys, etc.

Line 80 – “et al.” means “and others”, when there are only 2 authors we should not use this expression. Either the reference 30 is wrongly typed and some authors are omitted or this should be changed.

Lines 89 – 114 – if the Authors want to list something it would be better to list each point from a new verse, not in the middle of the line like at the current form. It would be clearer.

Methods

Lines 131 – 132 – the subject of the sentence is missing, who proposed a judgment method?

Lines 217 – 218 – the sentence is unclear, lacks conjunction

Starting from line 229 – again if the Authors want to list something it would be better to list each point from a new verse, not in the middle of the line like at the current form. It would be clearer.

Experimental procedure

If I understand correctly the PMLAB DIC-3D is a measurement system basing on optical images of the sheet taken during the test and the results are calculated based on the deformation and movement of prior sprayed on dots? The preparation of samples is not mentioned at all. What is the size of the dots, how were they obtained? If the cameras are tilted like at figure 8 how is it possible that the view is not blocked by the sheet forming machine (the cameras are not pointed directly at the sample). The procedure here is not clearly described.

The Authors mention in lines 293 – 296 what materials and at what temperature range can be tested with this method. But what are the limitations regarding the dimensions such as thickness. Is the 1.5mm the limit or is it the value imposed by the standard? Would it be possible for instance to test a sheet directly from TRC line with a thickness as high as 6mm? This is just my curiosity, it does not have to be addressed in the manuscript.

Results and Discussion

Using 3D measuring equipment for determining the FLC is not new. It can be found published in recent papers such as listed below, where the authors used similar equipment (Aramis provided by Zeiss). I am sure that there are much more published papers on the matter, since I have found these 4 in less than a minute of search and the Authors do not mention them as references. Considering this, what is the novelty of this paper?

https://doi.org/10.1016/j.jmrt.2022.12.120

https://doi.org/10.12776/ams.v21i4.639

https://doi.org/10.1016/j.ijmecsci.2022.107200

https://doi.org/10.1016/j.matdes.2014.01.012

Conslusions

The conclusions section is clear and based on the obtained results.

References

There are 34 references out of which 21 are 10 years old or older and many are over 30 years old meaning that in my opinion the references are quite outdated. It is not a bad thing to use such literature but not at such amount. In my opinion it would be beneficial to look for more recent literature. Reference 7 and 34 are repeated.

Comments on the Quality of English Language

There are minor mistakes regarding grammar, such as missing subject of the sentence or two long and ambiguous sentences. The issues were adressed in the main comments.

Author Response

As there are many answers, please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Review

The assessed paper describes in detail and analyzes the proposed two new criteria based on topography of large deformations to determine the failure of the sheet tapering and verifies the reliability of the new criteria using the existing time correlation method and the criteria of the time position correlation method. The authors formulated their analysis into four conclusions, which they introduced at the end of the paper. I agree with these conclusions. The clarification of the examined process is of great importance for scientific research and further application of knowledge in the following research.

 

1. In their paper, the authors publish and analyze their findings from the presented issue. Overall, the analyzed process has been described quite accurately and at a good level. All necessary and relevant information has been stated by the authors and incorporated in the text of the paper. The authors dealt with their topic on the basis and analysis of the professional resources in References.   At this point, I can say that, in my opinion, the assessed contribution meets all formal requirements for this kind of scientific articles. The division of the text is made into four chapters Plus Conclusions. Chapters logically, factually and quite accurately analyze and address the investigations under investigation. In the article, the chapters listed on each other and the reader is very easy to navigate in the text.   The assessed contribution shows that the authors have very well processed the issue. I can also say that the text of the submitted article is at a high level from the professional and scientific side. Introduction is made in detail and discussed contributions are at a high level analyzed because this section is important and forms the base for the type of post. The Methods Chapter is written in detail. The Applicant and the reader also described in detail the Experimental Procedure Chapter described a lot of valuable research information.   The chapter of RESULTS and Discussion is also very well filed and explained. From the text of this chapter, the reader will learn everything you need. Conclusion - I agree with the conclusions here, as I have already mentioned at the beginning. Perhaps it was necessary to emphasize the scientific contribution of the authors, which the authors could specifically and in detail.   At the end of this part of my opinion, I give an opinion - the results of the experiments confirm the great erudition of the authors. The authors of published research brought important knowledge and offer them for the following analysis and processing. 

2. As a reviewer on the question of the evaluation of the topic itself, I can state that, in my opinion, it was chosen correctly and well.   This analyzed topic will certainly impress the wide professional public. The experiments that the authors publish and describe in detail in the article under consideration show and confirm the required notice ability and also confirm the great erudition of the authors. I evaluate the presentation of the research under review, which was developed by the authors more than good. The benefit is that the research of authors fits very well in the scientific field. After the publication, the paper will become a good part of the entire spectrum of the mentioned issue.

3. The text of this paper confirms that the authors in the scientific field where they present are professionally. As a reviewer, I can say that the article is at a high level and after its small modifications it will become beneficial to the presented area.

4. The authors chose a methodology that I rate as the right one. I approve the perfectly elaborated chapter 2. For this kind of scientific contribution, the authors applied the right methodology. This also suggests how the division of the text of the post is chosen. I evaluate Chapter 2 and 3 most.

5. I think, in my opinion, that the authors formulated the experimental findings accurately and correctly. Experiments by the authors presented in the text of the paper are described at a high scientific level. The text of the post is complemented by appropriate images of high notice value.

6. References that the authors have summarized in the number of 34 are correctly listed. In my opinion, this area of research is sufficient.

7. The pictures reported in the text are well and correctly made. Table 1 must be adjusted to prevent the reader from distracting because it is quite wide. The pictures very well and logically complement the whole text and help to understand the findings and process of the authors in their research.

   

Comments, Accessories and Questions:

1. The pictures would be good to center. As mentioned, they are included appropriately and correctly, thereby complementing the above facts.

2. Edit table width number 1.

3. Consider the addition of the scientific benefit of the contribution.

 

The contribution after incorporating small adjustments may be published.

Author Response

Point 1: The pictures would be good to center. As mentioned, they are included appropriately and correctly, thereby complementing the above facts.

Response 1: We have centered the images in the paper.

Point 2: Edit table width number 1.

Response 2: We have adjusted the table table width.

Point 3: Consider the addition of the scientific benefit of the contribution.The contribution after incorporating small adjustments may be published.

Response 3: We have revised the article according to the valuable suggestions from you, the reviewers, and thank you again for the suggestions you gave to make the layout of our paper more reasonable and the content more rigorous.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for the time that you took to provide such an extensive review. I belive all my questions and doubts have been adressed. As for me the paper is fit for publication. You just need to correct the references in the text as for the references you have added sometimes the brackets are missing (almost all references from the introduction lack brackets in the text). Also there is no mention of reference 14 in the text. Also lines 328 and 454 - you have deleted some reference and now it states "Error! Reference source not found.."

Overall I am happy with the revision you have provided and wish you all the best.