Prediction of Friction Coefficient for Ductile Cast Iron Using Artificial Neural Network Methodology Based on Experimental Investigation

Round 1

Reviewer 1 Report

1) Fig. 8  delete it and illustrate the information in a text 

2) Table 3 has too much data inside, I suggest decreasing it and summarizing the most important information and representing it.

3) Mention the equation numbers in the text instead of ( the following equation)

4) Table 1 the values were measured or standard, if measured where is the test or if standard where is the reference?

5) The novelty of the paper is not highlighted the data shows that it was repeated from other research. 

6) line 92-93 Al yuda Neuro’s intelligence software (put a reference)

7) the references are too few for this kind of research, please enhance the results and the introduction with the relevant literature. such as https://link.springer.com/article/10.1007/s11831-022-09714-x.

 

Author Response

Dear Reviewer # 1,

Thank you for your useful comments and suggestions on our manuscript, we have modified it accordingly. In the manuscript file, we used the option “Track changes” in order to identify the new corrections which are highlighted in red colour. We are very grateful for your consideration. The detailed corrections are listed below point by point:

 

1) Fig. 8  delete it and illustrate the information in a text

• Figure 8 has been deleted, and a new text to replace it was added to section 4.2.1.

 

2) Table 3 has too much data inside, I suggest decreasing it and summarizing the most important information and representing it.

• Table 3 has been shortened as suggested.

 

3) Mention the equation numbers in the text instead of (the following equation)

• The equation numbers have been mentioned in the text as recommended.

 

4) Table 1 the values were measured or standard, if measured where is the test or if standard where is the reference?

• The chemical composition of the samples was determined using an optical emission spectrometer (branded SPECTROMAXx) for the chemical analysis to find the element percentages included in the composition of ductile cast iron, as listed in Table 1. These details were added to section 2.1.

 

5) The novelty of the paper is not highlighted the data shows that it was repeated from other research.

• In this paper, there are absolutely no data repeated from other research. However, more details were incorporated into the Introduction chapter to highlight the article's novelty.

 

6) line 92-93 Al yuda Neuro’s intelligence software (put a reference)

• Many thanks to the respected reviewer for noticing this. We would like to clarify that Al yuda Neuro’s intelligence is the name of the software (not a name of a researcher) used in the work of “Soni et al.”, the reference number [12], which is mentioned in the previous sentence.

7) the references are too few for this kind of research, please enhance the results and the introduction with the relevant literature. such as https://link.springer.com/article/10.1007/s11831-022-09714-x

• Further relevant references have been cited in the revised version of our manuscript, including the suggested article.

 

 

Thank you for your precious time and kind efforts to improve our manuscript. We look forward to your positive response.

 

Yours Sincerely,

Corresponding Author

Author Response File: Author Response.docx

Reviewer 2 Report

This is an interesting and useful paper. I have a few comments which may help the authors improve the paper still further. 

1. The authors should emphasize in the paper that friction and wear are properties of the whole system, not just the materials. In particular, the surface roughness will greatly influence the results. The authors should state what the surface roughness parameters are (RMS roughness etc.)

2. It is usual to expect "running-in" to occur in sliding systems, so that you would normally expect higher wear at the start of the test, and as the test progresses, the wear should stabilize. In terms of wear rate, you would usually expect a higher wear rate at start of test and then a lower wear rate later. Figure 7 does not show this effect. Can the authors explain why? It would also be useful in Figure 7 to have some indicative error bars. 

3. Is the wear mechanism the same for the different operating conditions used in the experiments? If the wear mechanism changed (e.g. from mild abrasive to adhesive) as the load increased, this could significantly affect the predictions. You would, I think, need a separate model for the different wear regimes. The authors should comment on this.  

Author Response

Dear Reviewer # 2,

Thank you for your useful comments and suggestions on our manuscript, we have modified it accordingly. In the manuscript file, we used the option “Track changes” in order to identify the new corrections which are highlighted in red colour. We are very grateful for your consideration. The detailed corrections are listed below point by point:

 

1. The authors should emphasize in the paper that friction and wear are properties of the whole system, not just the materials. In particular, the surface roughness will greatly influence the results. The authors should state what the surface roughness parameters are (RMS roughness etc.)

• Authors totally agree with the respected reviewer regarding the influence of surface roughness on the results. “However, in this work, the roughness for all sliding surfaces of testing specimens, as well as the sliding disk, was the same to allow the influence of other parameters to be investigated. The surface roughness of the testing samples after polishing was 0.15 µm, while the surface roughness of the sliding disk after fine grinding was 0.35 µm. The roughness was determined using the Taly surf Talyor-Hobson device for surface roughness measurement.” These details were added to section 2.2.3.

 

2. It is usual to expect "running-in" to occur in sliding systems, so that you would normally expect higher wear at the start of the test, and as the test progresses, the wear should stabilize. In terms of wear rate, you would usually expect a higher wear rate at start of test and then a lower wear rate later. Figure 7 does not show this effect. Can the authors explain why? It would also be useful in Figure 7 to have some indicative error bars.

 

• Thank you, dear respected reviewer, for pointing this important issue out. The running-in stage can be visible if the examined material’s behavior curve is given from the beginning of the test. However, in Figure 7, each apparent point represents one value of the wear rate results at the stable stage which is determined using the weighing method. Due to this method procedure, the running-in stage is not shown.

The following details were added to section 2.2.3.

“The wear rate was determined using the weighing method by calculating the lost weight of the samples according to the following steps:

• Weighing the sample before each test using a sensitive balance with a sensitivity of 0.0001 g, where the weight of the specimen before the test was (3.0195 g).
• Determining the parameter whose effect is to be studied on the wear rate (e.g., sliding time) and fixing all other parameters (normal load and sliding speed).
• Installing the sample to be tested with the wear device, placing it perpendicular to the sliding disk, and then operating the device for specified periods. The piece is weighed after the test, and to calculate the wear rate, Equation (2) was used [20]”.
• The error bars have been included in Figure 7, as recommended.

 

3. Is the wear mechanism the same for the different operating conditions used in the experiments? If the wear mechanism changed (e.g. from mild abrasive to adhesive) as the load increased, this could significantly affect the predictions. You would, I think, need a separate model for the different wear regimes. The authors should comment on this

• Many thanks to the respected reviewer for such a valuable comment. The wear mechanism was almost the same throughout the testing time, as no occurrence of any sudden phenomenon was recognized, such as big noise or vibration due to the stick-slip. Therefore, we believe that the current model is enough to represent the prediction.

 

 

 

Thank you for your precious time and kind efforts to improve our manuscript. We look forward to your positive response.

 

Yours Sincerely,

Corresponding Author.

Author Response File: Author Response.docx

Reviewer 3 Report

In its current form, the work is not suitable for publication. Notes attached.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer # 3,

Thank you for your useful comments and suggestions on our manuscript, we have modified it accordingly. In the manuscript file, we used the option “Track changes” in order to identify the new corrections which are highlighted in red colour. We are very grateful for your consideration. The detailed corrections are listed below point by point:

 

1. what is the magnification of the photos shown in Figures 1, 2 and 3?

• The magnification has been added to the caption of the mentioned figures.

 

2. what was the surface roughness of the prepared samples?

• The surface roughness of the testing samples after polishing was 0.15 µm, while the surface roughness of the sliding disk after fine grinding was 0.35 µm. These details were incorporated into section 2.2.3.

 

3. Using the same designation (letter W) for the frictional force and weight of the samples is

misleading.

• Many thanks to the respected reviewer for noticing this. The designation of the applied load has been changed to L rather than W.

 

4. What was the pin made of and what were its geometric parameters?

• The dimensions of the pin and the material it is made of are mentioned in the first sentence of section 2.1.

 

5. was the test conducted under dry friction conditions or what lubricant was used?

• Thank you, dear respected reviewer, for pointing this out. The tests were conducted under dry sliding conditions. This has been clarified in section 2.2.3.

 

6. In the paragraph beginning at line 170, use subscripts in defining terms, as it is written in

formula (5).

• It is done as recommended.

 

7. In the text, the unit of area is repeatedly written incorrectly - there is "mm2", and it should be "mm2".

• The unit mentioned has been corrected throughout the manuscript.

 

 

8. In line 187, the diameters of the nodules are shown with an incorrect unit.

• The unit of the nodules’ diameters was corrected.

 

9. How was the measurement of the weight wear of samples carried out?

• The following details have been incorporated into section 2.2.3.

“The wear rate was determined using the weighing method by calculating the lost weight of the samples according to the following steps:

• Weighing the sample before each test using a sensitive balance with a sensitivity of 0.0001 g, where the weight of the specimen before the test was (3.0195 g).
• Determining the parameter whose effect is to be studied on the wear rate (e.g., sliding time) and fixing all other parameters (normal load and sliding speed).
• Installing the sample to be tested with the wear device, placing it perpendicular to the sliding disk, and then operating the device for specified periods. The piece is weighed after the test, and to calculate the wear rate, Equation (2) was used [20]”

 

10. The presentation of the measurement results in the form of a description in section 4.1 is very incomprehensible. There is a lot of information there, written in a chaotic way, which makes it very difficult to understand the results of the experiment.

• Section 4.1 has been rearranged. Firstly, it was divided into paragraphs to be more organized and understandable. Then, all paragraphs were summarized, and the redundant information was eliminated.

 

11. The effect of temperature on the coefficient of friction that the author writes about (lines 194-198) is undoubtedly present, but he cannot indicate here that it causes an increased amount of oxides in the wear sliver, since he did not perform any analysis.

• The respected reviewer is absolutely right. Therefore, the sentence about increasing the oxide has been deleted to avoid any doubtful information.

 

12. why did the authors not specify the wear rate of sample 1?

• We beg your pardon, dear respected reviewer. The wear rate of specimen 1 was forgotten by mistake. It has been added in the revised version.

 

13. There is a misspelling of the word "coefficient" in the description of the left vertical axis

in the graph of Figure 6, and there is no power symbol on the right axis.

• The issues mentioned (misspelling and power symbol) were fixed.

 

14. the authors write about the better properties of the bainite structure than the ferrite structure, however, it is not clear from which measurements this is due?

• We have rewritten this paragraph to be more clear and understandable, as follows

“Figure 7 shows the impact of the microstructure produced by heat treatments (annealing and isothermal processes) on the wear rate. The sliding time was the variable parameter, while the other parameters (applied load and sliding speed) were kept constant. It is clearly shown in the figure that the bainite structure produced a lower wear rate than the ferrite structure. This is due to the fact that the resistance of the bainite structure's surface layers to plastic deformation is higher than the ferrite structure because of the bainite structure's higher hardness (320 HV). On the other hand, the ferrite structure's lower hardness (145 HV) generates a plastic flow and increases the size of the contact area. It also causes weak resistance due to its softness and readily adheres to the opposing surface.”

 

15. how many repetitions of tribological tests were performed?

• Three identical specimens were tested for each examined condition. This was mentioned in section 2.2.3.

 

16. what was the actual weight wear of the samples? What happened to the wear products?

• As mentioned in answer to point 9, the weight of the specimen before the test was (3.0195 g). The wear rate was determined using the weighing method by calculating the lost weight of the samples. The sample was installed to be tested with the wear device, placing it perpendicular to the sliding disk and then operating it for specified periods. The piece is weighed after the test, and to calculate the wear rate, Equation (2) was used. These details were added to section 2.2.3. Also, Table 2 (A new table was added to the paper) demonstrates the weight loss for one of the samples tested under specific operating conditions.

 

 

Thank you for your precious time and kind efforts to improve our manuscript. We look forward to your positive response.

 

Yours Sincerely,

Corresponding Author

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

the modification has been added 

Author Response

Many thanks, dear respected reviewer, for accepting all our answers and modifications.

Reviewer 2 Report

The revised manuscript has answered the questions I asked in the 1st review, and the paper is now acceptable for publication

Author Response

Many thanks, dear respected reviewer, for accepting all our answers and modifications.

Reviewer 3 Report

Dear Authors,

Thank you for following my comments. In its current form, the work meets the formal conditions for scientific papers. The experiment is correctly described and the results are clearly presented which allows for their eventual reproduction. However, I would like to note that the work touches on the subject of tribological wear of cast iron which has been used for decades as a good material for use in friction nodes. In view of this, the work does not have very significant novelties.

Author Response

Many thanks, dear respected reviewer, for accepting all our answers and modifications.

Regarding your further concern, the novelty of the present study is highlighted in the Introduction chapter (Lines 98-102). Also, a new paragraph (last paragraph) has been added to the conclusions to clarify how other researchers can use the findings of this work.

Thank you for your precious time and kind efforts to improve our manuscript. We look forward to your positive response.