Contact Analysis for Cycloid Pinwheel Mechanism by Isogeometric Finite Element
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe article is correct. I think it is a step forward for the method of calculating cycloid gears and contributes to the scientific development of the authors. However, I have the impression that the article was written with a assumptioned thesis that isogeometric method is better than FEA.
Here are some of my attentions:
Table 2 shows the relative errors Fy (very small in relation to the other dimensions). What effect does it have on the result, since the numerical calculations are only approximate ? Even the authors write about it in verses 194-197. In addition, the relative error in the description and in the table is marked differently (fy, Fy).
In Figures 3A and 3B it is not the same area (Boundary comparison illustrates: (a) NURBS surface boundary; (b) Lagrange mesh of FEM). The presented grid, according to what assumptions it was created.
Regarding the define of the FEM mesh, I have the most objections:
I did not find important information, e.g. what type of finite elements were used in the calculations (triangular or maybe tetra - better)?
What was the distribution of elements in the model (equally arranged or compacted on the surface)?
Were the elements linear or square?
In the aforementioned Ansys workbench program, it is possible to control the distribution of elements, e.g. along edges, and then it will correspond exactly to the one shown in Fig. 3(A).
These only a few selected comments concerning the preparation of the model for FEM calculations affect both the time and quality of calculations, and this is what the authors tried to analyse (line 468-470).
In addition, I wonder about the sense of analysing Fy errors from Table 2, e.g. with reference to the diagram Fig. 12 or Fig. 18 and 19. How isogeometric affects the results.
In my opinion, Figure 21 gives the same examples several times. If I am wrong (because maybe I cannot see correctly), please point to the picture or describe the differences in more detail.
According to Table 6, the FEM method gives more accurate results! which does not agree with the description in the table below. I hope it is just a mistake in the table6.
Finally, I suggest correcting the obvious editorial mistakes and supplementing the article with the information indicated about the FEM model adopted for comparison. After the corrections are made, the article may be published, as it contains a description of the application of the isogeometric method, but I would recommend less determined conclusions regarding the legitimacy of its widespread use in calculations.
Author Response
Reviewer #1:
- Response to comment: Table 2 shows the relative errors Fy (very small in relation to the other dimensions). What effect does it have on the result, since the numerical calculations are only approximate ? Even the authors write about it in verses 194-197. In addition, the relative error in the description and in the table is marked differently (fy, Fy).
Response: We have made correction according to the Reviewer's comments in Table 2. Table 2 is used to compare the geometric tooth profile generated by the NURBS function with the theoretical function. It is not the results of contact analysis.
- Response to comment: In Figures 3A and 3B it is not the same area (Boundary comparison illustrates: (a) NURBS surface boundary; (b) Lagrange mesh of FEM). The presented grid, according to what assumptions it was created.
Response: Fig.3A and 3B is created by intercepting the same partial location of model from NURBS and FEM model.
- Response to comment:
Regarding the define of the FEM mesh, I have the most objections:
I did not find important information, e.g. what type of finite elements were used in the calculations (triangular or maybe tetra - better)?
What was the distribution of elements in the model (equally arranged or compacted on the surface)?
Were the elements linear or square?
In the aforementioned Ansys workbench program, it is possible to control the distribution of elements, e.g. along edges, and then it will correspond exactly to the one shown in Fig. 3(A).
These only a few selected comments concerning the preparation of the model for FEM calculations affect both the time and quality of calculations, and this is what the authors tried to analyse (line 468-470).
Response: Solid186 is used in FEM and ANSYS software, which is tetrahedron element and quadratic. The meshing in IGA and FEM is essentially uniform.
- Response to comment: In addition, I wonder about the sense of analysing Fy errors from Table 2, e.g. with reference to the diagram Fig. 12 or Fig. 18 and 19. How isogeometric affects the results.
Response: Table 2 is used to compare the geometric tooth profile generated by the NURBS function with the geometric tooth profile generated by the theoretical tooth profile function. fy is an indication of the geometric error of the tooth profile, and Figures 18 and 19 show the contact stress distribution.
- Response to comment: In my opinion, Figure 21 gives the same examples several times. If I am wrong (because maybe I cannot see correctly), please point to the picture or describe the differences in more detail.
Response: We have added this part based according to the Reviewer's suggestion on page 15. "Comparison of geometric and finite element results under different number of units of model surface division, to verify the accuracy of geometric analysis method under less units of cycloid pinwheel tooth surface, and to select the contact stress of the pin with the largest force to make a comparison of the results, and the crankshaft input angle of 0 degrees, the cycloid gear and the pin will be arranged with different number of NURBS units for each NURBS tooth surface, and the mechanism of the NURBS model is shown in Fig. 21."
- Response to comment: According to Table 6, the FEM method gives more accurate results! which does not agree with the description in the table below. I hope it is just a mistake in the table 6.
Response: We are very sorry for our incorrect writing, and we have made correction in the table 6.
- Response to comment: I suggest correcting the obvious editorial mistakes and supplementing the article with the information indicated about the FEM model adopted for comparison.
Response: We have made correction according to the Reviewer's comments.
Special thanks to you for your good comments.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe research is on Contact Analysis for Cycloid Pinwheel Mechanism by Isogeo metric Finite Element. The following comments must be addressed before accepting the manuscript.
Rewrite the abstract by highlighting the critical results in % increase or decrease value.
At the end of the abstract, mention the application of the proposed research.
Fit the headings in standard research article format i.e 1. Introduction, 2. Materials and methods, 3. Results and discussion, 4. Conclusion, and References.
The literature is not thoroughly investigated as it is missing recent literature. It is advised to include a minimum 5 to 10 papers from 2023, and 2 to 3 papers from 2022.
Rewrite the sentence “The contact analysis model designed based on the traditional FEM is formed on the original geometric model using Lagrangian basis functions to generate the mesh, which makes the geometric boundary low order continuity and ignores some detailed features.”
The novelty and clear objective is missing at the end of the introduction.
In table 2, units are missing.
For FEM study how are the mesh element numbers and node numbers decided? Have you performed mesh convergence analysis? If so include it in the manuscript.
Modify the English as the manuscript has lot of typos, sentence connections, and grammatical errors.
Write the conclusions in bullet points.
Comments for author File: Comments.pdf
Modify the English as the manuscript has lot of typos, sentence connections, and grammatical errors.
Author Response
Reviewer #2:
- Response to comment: Rewrite the abstract by highlighting the critical results in % increase or decrease value.
Response: We have made correction according to the Reviewer's comments.
- Response to comment: At the end of the abstract, mention the application of the proposed research.
Response: We have made correction according to the Reviewer's comments.
- Response to comment: Fit the headings in standard research article format i.e 1. Introduction, 2. Materials and methods, 3. Results and discussion, 4. Conclusion, and References.
Response: As suggested by the reviewer, we have adjusted the headings. The heading of "Geometry model of cycloidal gear for Isogeometric contact analysis " were changeded as "Cycloidal gear Isogeometric contact analysis" on page 2. And the heading of "Procedure of Isogeometric contact analysis for cycloid pinwheel" were changeded as "Calculation of Isogeometric contact analysis for cycloid pinwheel" on page 6.
- Response to comment: The literature is not thoroughly investigated as it is missing recent literature. It is advised to include a minimum 5 to 10 papers from 2023, and 2 to 3 papers from 2022.
Response: We have added the literatures based according to the Reviewer's suggestion.
Response: Several new references are added in the list.
- Response to comment: Rewrite the sentence "The contact analysis model designed based on the traditional FEM is formed on the original geometric model using Lagrangian basis functions to generate the mesh, which makes the geometric boundary low order continuity and ignores some detailed features."
Response: We have re-written this part according to the Reviewer's suggestion. The statements of "The contact analysis model designed based on the traditional FEM is formed on the original geometric model using Lagrangian basis functions to generate the mesh, which makes the geometric boundary low order continuity and ignores some detailed features" were corrected as "The contact model built by the traditional FEM is formed using Lagrangian basis functions to generate the mesh, which makes the geometric boundary low order continuity and ignores some detailed features" on page 6.
- Response to comment: The novelty and clear objective is missing at the end of the introduction.
Response: We have re-written this part according to the Reviewer's suggestion. The statements of " In this paper, the isogeometric analysis method was introduced to analyze the meshing contact between the teeth of a cycloid pinwheel transmission, and The NURBS surface was used to construct the model of the cycloid gear and other components, which was substituted into the IGA contact analysis process to analyze the contact force performance of the gear teeth under a given load. The accuracy of the isogeometric analysis results was verified by the cycloid pinwheel transmission theory. Besides, it was compared with the finite element method, highlighting the advantages of IGA in contact analysis. " were corrected as " Contact analysis used to be investigated by only FEM with more computational effort. In this paper, the isogeometric analysis method was originally introduced to analyze contact stress for a cycloid pinwheel transmission. The NURBS surface was used to construct the model of the cycloid gear and other components, which was integrated into the IGA contact analysis process to solve the contact stress of the cycloidal gear teeth under a given load. The accuracy of the isogeometric analysis results was verified by the theoretical values based on cycloid pinwheel transmission principle. Besides, it was also compared with the finite element method, highlighting the advantages of IGA in contact analysis." on page 2.
- Response to comment: In table 2, units are missing.
Response: We are very sorry for our negligence of the unit. This has been corrected in table 2(p. 5).
- Response to comment: For FEM study how are the mesh element numbers and node numbers decided? Have you performed mesh convergence analysis? If so include it in the manuscript.
Response: This article did not conduct computational mesh fitting analysis is performed because ANSYS software can guarantee the accuracy of the results when the computation converges, and this paper also also verifies the reliability of ANSYS results from the comparison between ANSYS results and theoretical results.
- Response to comment: Modify the English as the manuscript has lot of typos, sentence connections, and grammatical errors.
Response: We have made correction according to the Reviewer's comments.
- Response to comment: Write the conclusions in bullet points.
Response: Considering the Reviewer's suggestion, we have readjusted this part on page 17.
Special thanks to you for your good comments.
We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper. And here we did not list the changes but marked in red in the revised paper.
We appreciate for Editors/Reviewers' warm work earnestly, and hope that the correction will meet with approval. If you have any questions, please contact us at any time and we will reply to you as soon as possible.
Once again, thank you very much for your comments and suggestions.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsAs the authors incorporated the changes, hence it can be accepted for publication.
