Space Node Topology Optimization Design Considering Anisotropy of Additive Manufacturing
Round 1
Reviewer 1 Report
This article is about the extremely intriguing topic of additive manufacturing. This article explores the anisotropy of mechanical properties of additively built objects and explains it in depth. This well-written article will facilitate future research in this field. The manuscript is suitable for publication in this journal following a few minor revisions. Please see the recommended clarifications listed below.
1. The abstract needs to be rewritten as in current form it is too lenghthy and difficult to understand for potential readers.
2. The authors have utilised the BESO technique, but the SIMP approach is considered superior. Please explain why BESO was chosen over other, superior options.
3. A SEM analysis is not an experiment. Please rewrite as study, analysis or a suitable alternative.
4. The ASTM E8 standard applies to the tensile testing of metallic components, with the exception of additively manufactured components. Please justify the choice.
Following the aforementioned clarifications, the article is ready for publication.
Author Response
Response to Reviewer 1 Comments
Point 1: The abstract needs to be rewritten as in current form it is too lenghthy and difficult to understand for potential readers.
Response 1: We are very grateful to Reviewer for reviewing the paper so carefully. We have carefully considered the suggestion of the Reviewer and made some changes to the abstract.
Point 2: The authors have utilised the BESO technique, but the SIMP approach is considered superior. Please explain why BESO was chosen over other, superior options.
Response 2: Dear reviewer, we agree with you that the SIMP method is the superior method at present. Especially in some currently finite element analysis software, the SIMP method is used frequently. We planned to use the SIMP method in the beginning, but we changed it, there several reasons below.
- We must honestly tell you that we use the BESO method because we have got some achievements in it before, and we have some mature technologies and experience in using this method.
- We think that the BESO method is more suitable than the SIMP method in the research on space nodes. Because we have compared the two methods in the paper which can be searched on' https://doi.org/10.3390/ma15113874'. A space node is a structure with complex stress, some parts of it have high stress, some are low. The SIMP method has the possibility to delete the elements which link to weak structures by mistake at the first calculation loop step when the target volume is far small than the original volume. Because it will reach the target volume at the first step and delete some may necessary elements without repairing in the next steps. But the BESO method can save the weaker structures well during the optimization process because the volume is reduced gradually instead of reaching the goal volume immediately. Thereby we think the BESO method has a benefit in space node optimization.Thereby we think the BESO method has a benefit in space node optimization.
- Although the SIMP method seems to be better now, it is difficult to say with absolute certainty which method is suitable for all applications. At present, many improved algorithms have also shown certain advantages in some specific occasions. We believe that the study of these less-used algorithms will help the progress of topology optimization methods.
Point 3: A SEM analysis is not an experiment. Please rewrite as study, analysis or a suitable alternative.
Response 3: Thank you for your precious advice, we have revised it.
Point 4: The ASTM E8 standard applies to the tensile testing of metallic components, with the exception of additively manufactured components. Please justify the choice.
Response 4: In fact, we were hesitant when we choose sample styles at the beginning. But we decided to use the ASTM E8 finally. There are several causes given below.
- The standard which relates to the testing of additive manufacturing is the ASTM F3122, it gives a lot of relevant standards, and the tension testing standard is suggested to use ASTM A370. However, in the A370 there is no content about additive manufacturing parts, just including forged steel and cast steel.
- At the same time, we find many relevant papers that also used the ASTM E8 standard. These papers gave us some enlightening that we think the 316L steel made by SLM also can use the ASTM E8 standard. In addition, we think using the same standard which is used in other papers to manufacture some samples during our reasch can ensure contrast effectively with the results that other papers did.(The relevant papers which used the E8 standard(DOI):1108/RPJ-04-2016-0068; 10.1016/j.actamat.2020.08.066; etc.)
- The third point is that not only in the ASTM standard but also in the Chinese standard GB35022, also has not given a certain rule, but suggests that the part of tension testing can according to the general metal testing method standard GB/T228.
- The common idea of the tension testing of additive manufacturing products is to get reliable data. Our tension testing samples got some nice data that were not discrete, it can prove the manufacturing technology is stable and the data is useful.
Author Response File: 
Author Response.docx
Reviewer 2 Report
In the manuscript “Space Node Topology Optimization Design Considering Anisotropy of Additive Manufacturing” an anisotropic optimization analysis was carried out on the space nodes in combination with additive manufacturing was investigated.
The current work is well presented and with complete experimental verification in a very interesting subject. So, it would be advisable to publish it after the following minor advisors:
1. I suggest authors add some recent (2021-2022) references to the subject matter, of the anisotropy behavior check. Some of the following, or other similar, could be added:
doi:10.3390/designs6050073
doi:10.3390/app12157386.
2. Despite the framework of Matlab and Python contribution is performed, it would be very helpful to add further details about the contribution of the above tools.
3. In the first line which belongs to the first paragraph after figure 15 I suppose that the ‘Figure5’ must change to ‘Figure15’.
Author Response
Response to Reviewer 2 Comments
Point 1: I suggest authors add some recent (2021-2022) references to the subject matter, of the anisotropy behavior check. Some of the following, or other similar, could be added:
doi:10.3390/designs6050073
doi:10.3390/app12157386.
Response 1: Dear reviewer, thank you for recommending the article. These two articles make our article more informative. We have added and marked it in the fourth paragraph of the introduction to the article, please review.
Point 2: Despite the framework of Matlab and Python contribution is performed, it would be very helpful to add further details about the contribution of the above tools.
Response 2: Dear reviewer, according to your suggestion, we have supplemented the relevant details in the description of the algorithm process in section 2.1 of the article, thank you for your patient review.
Point 3: In the first line which belongs to the first paragraph after figure 15 I suppose that the ‘Figure5’ must change to ‘Figure15’.
Response 3: Dear reviewer, we are sorry for such a mistake, we have corrected it.
Author Response File: Author Response.docx
Reviewer 3 Report
The manuscript entitled “Space Node Topology Optimization Design Considering Anisotropy of Additive Manufacturing” conducted anisotropic optimization analysis on the space nodes based on BESO and SLM where both numerical and experimental results are presented. The whole paper is logically structured, and the writing is acceptable but can be improved. Some descriptions are not accurate, and some errors are found in the equations about BESO. Therefore, the Reviewer recommends the major revision. The following comments must be addressed for further consideration.
1. In Introduction, the authors should also mention some newly developed topology optimization algorithms such ETO, FPTO, and SEMDOT to show authors’ knowledge in this field. Some related papers are:
https://link.springer.com/article/10.1007/s00158-017-1846-6
https://www.sciencedirect.com/science/article/abs/pii/S0965997820309674
https://www.sciencedirect.com/science/article/abs/pii/S0965997820309881
2. In Introduction, “Additive manufacturing technology has emerged and is well known in the form of 3D printing, which enables the direct fabrication of topologically optimized structures.”
The authors need to add references to support this statement. Some related papers are:
https://www.tandfonline.com/doi/abs/10.1080/17452759.2019.1637023
https://www.tandfonline.com/doi/full/10.1080/17452759.2019.1644185?src=recsys
3. Page 3: “The BESO method is one of the most popular continuum topology optimization
methods.” BESO is a discrete method. SIMP is a continuum method. Please double-check the papers about BESO written by Profs. Xiaodong Huang and Mike Yi Min Xie carefully.
4. Equations (2)-(9) should be modified. BESO needs the material penalization scheme, and hence the penalty factor is required in Equation (2). The authors also mentioned the penalty but gave wrong equations.
It is understood that the authors only use BESO for application, but a correct understanding bout the algorithm is also very crucial.
Two typical BESO papers are:
https://www.sciencedirect.com/science/article/abs/pii/S0168874X07000777
https://link.springer.com/article/10.1007/s00466-008-0312-0
5. In terms of Figure 2, the contents on the right hand side can be removed, which is not useful.
6. In Conclusion, “Based on Abaqus finite element solver, this paper develops the BESO algorithm through Matlab programming.” This statement is not accurate and confusing. BESO is not developed by the authors. You should make this sentence more detailed to highlight what you did in this work. For example, integrated optimisation platform for topology optimization considering anisotropy of AM.
7. In Conclusion, there are two very long bullet points. The authors should shorten them or have more bullet points for ease of reading.
8. At last, it is better to further polish the writing before resubmitting the manuscript. For example, Page 14 “Keep the nodal conditions consistent, set the material properties of the engineering elastic constants in the finite element calculation software, and define the application direction of the parameters.” Complete sentences are required. The authors should improve the writing across the whole paper.
Author Response
Response to Reviewer 1 Comments
Point 1: In Introduction, the authors should also mention some newly developed topology optimization algorithms such ETO, FPTO, and SEMDOT to show authors’ knowledge in this field.
Response 1: Thank you very much for your detailed comments and recommended articles. We have added in the introduction.
Point 2: In Introduction, “Additive manufacturing technology has emerged and is well known in the form of 3D printing, which enables the direct fabrication of topologically optimized structures.”
The authors need to add references to support this statement.
Response 2: I admire your rigorous logic and these articles broaden my horizons greatly. Based on your comments, it has been added to the article.
Point 3: Page 3: “The BESO method is one of the most popular continuum topology optimization methods.” BESO is a discrete method. SIMP is a continuum method. Please double-check the papers about BESO written by Profs. Xiaodong Huang and Mike Yi Min Xie carefully.
Response 3: Your question is very good. Because we express it wrong. We want to say ’ The BESO method is one of the most popular topology optimization methods of the continuum structures’ instead of ‘The BESO method is a continuum topology optimization method’. We apologize for our mistakes. We have modified it
Point 4: The ASTM E8 standard applies to the tensile testing of metallic components, with the exception of additively manufactured components. Please justify the choice.
Response 4: Equations (2)-(9) have be modified. It has been tagged in the article.
Point 5: In terms of Figure 2, the contents on the right hand side can be removed, which is not useful.
Response 5: We have corrected it. It has been tagged in the article.
Point 6: In Conclusion, “Based on Abaqus finite element solver, this paper develops the BESO algorithm through Matlab programming.” This statement is not accurate and confusing. BESO is not developed by the authors. You should make this sentence more detailed to highlight what you did in this work. For example, integrated optimisation platform for topology optimization considering anisotropy of AM.
Response 6: Dear reviewer, we are sorry that our statement is inappropriate. We have corrected it in the introduction and conclusion. It has been tagged in the article.
Point 7: In Conclusion, there are two very long bullet points. The authors should shorten them or have more bullet points for ease of reading.
Response 7: Dear reviewer, your suggestion is quite reasonable. The conclusion is truly too long and difficult to read. We are sorry that we ignored it. We have re-simplified it to four points that may be will easily to read.
Point 8: At last, it is better to further polish the writing before resubmitting the manuscript. For example, Page 14 “Keep the nodal conditions consistent, set the material properties of the engineering elastic constants in the finite element calculation software, and define the application direction of the parameters.” Complete sentences are required. The authors should improve the writing across the whole paper.
Response 8: Dear reviewer, we admire that you are so rigorous and patient， the papers you give are very helpful to us. We have rechecked this paper and adjusted some sentences, which have been marked in the article.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
This paper can be published in the current form. The reviewer encourages the authors to read more papers about topology optimization algorithms in the future.
