Guidelines for Topology Optimization as Concept Design Tool and Their Application for the Mechanical Design of the Inner Frame to Support an Ancient Bronze Statue

Round 1

Reviewer 1 Report

I do not consider that changes to the content are necessary but edits are needed on the final paragraphs (e.g. authors' contribution section).

Author Response

Authors wish to thank reviewers for their suggestions and remarks. We hope that enhancements will accomplish the requests and will be appreciated.

Response is reported in the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Summary: This paper investigates Topology Optimization as a concept design tool in mechanical engineering, providing the workflow to assess its application starting from the list of requirements to the stage of providing a conceptual design of a product.

Broad comments: I recognize the efforts placed in the elaboration of the manuscript in the design of the inner frame to support the ancient bronze as well in the detailed literature review. The introduction section is very easy to follow.

Although the design and development of products valuable in the field of culture and history are important, the paper does not provide any significant contribution to the current knowledge in design, product development, mechanical engineering, materials and/or manufacturing. The paper mainly reporting a conceptual design process using a topology optimization tool by generating conceptual design of inner support rather than a research project that in deep explains differences/benefits between/of the presented workflow towards the several existing concept design processes. Relations/Differences towards other conducted studies are missing in the discussion as well as the scientific contribution based on the results. Authors should dig deeper into the results by presenting some in-depth discussion in order to present differences between this and the design accomplished with the classic design approach to proving the benefits of this study. Overall, it would be nice to see that the authors explained how the implementation of the topology optimization tool can replace steps in the classical conceptual design workflow of a product. Design is an iterative process in nature and the paper, while aiming at describing a process, seems to focus only on the outcome. Considering this, I regretfully suggest rejecting the paper.

Here are some questions that might help in further research: Does the list of the requirements demands different interpretations in order to be suitable for the definition of constraints in topology optimization software? Probably this was the collaboration of mechanical engineers with experts from the field of culture and history, are they and how are they being involved in the design process? How was the gathering process of the requirements list went? Has it been a survey? What about the evaluation procedure within the presented workflow? Evaluation against technical and economic criteria? Criteria to reject/accept the concept variants and to choose the possible best or it is just about how can someone interpret the results towards the requirements? Etc.

Comments for author File: Comments.pdf

Author Response

Authors wish to thank reviewers for their suggestions and remarks. We hope that enhancements will accomplish the requests and will be appreciated.

Response is reported in the attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper concerns implementation of topology optimization method to the designing process of the support using in restoration of the ancient statue. This idea seems to be very interesting in the context of numerous and universal applications of TO method. The challenges in proposed implementation are the specific requirements for the support, which must be fulfilled for the restoration of structures with structural and material damage.

In the reviewer’s opinion, there are several aspects the authors should address in the manuscript before it can be recommended for publication.

Major:

1. The paper is interesting, but gives the impression of a ‘case study’ article i.e. presentation of the application of specific software in selected area without introducing new content into topology optimization as a concept design tool (apart of the interesting area of implementation). Please specify in a few words how the paper provide an advance in current state of art of topology optimization as a concept design tool.
2. Only a visualization of the results is presented, without reference to a quantitative solutions. There is no comment about fulfilment of defined requirements. There is no possibility to verify the results by the readers. Please justify this way of presentation of the results.
3. The comparison of TO results and the actual engineered solution relying on the visualization of both final designs of supports is not sufficient. There is no explanation why the obtained TO solution is attractive – the justification of applying the TO method in the considered example is not specific enough.

Minor:

1. Line 123: The general assumption: “…TO is a Finite Element Method (FEM) based formulation…” is wrong. One can find numerus papers related to finite volume method, finite-difference method, meshless methods and other applied as an analysis tool for topology optimization.
2. Page 3, reference 1: please revise the formula (instead of “P” – penalisation factor – there is “?”)
3. Formula (2): repetition.
4. Line 154: “therefore?” no spacing between words.
5. Line 154: ?=(1/2)?/? – please revise the formula: should F be in the power of 1 (not 2)?
6. Section 2.1, paragraph 2: the explanation is not convincing

• K is defined as the stiffness matrix; in FEM formulation the stiffness matrix is singular, so 1/K can not be defined, but it is used in line 155
• On the other hand: firs compliance C is inversely proportional to K (line 155) but in formula (4) C is directly proportional to element stiffness matrices k_o

Please revise/explain this paragraph in the context of above concerning.

7. Line 169: please define the ‘weighted compliance’.
8. Figure 4: it is underline in the paper, that localization of weakened material zones is very important for the design process, but there is no comment on the material model used for the presented map (and further investigations). Are the weakened  material zones included in the calculations (if yes: please explain how)?

Author Response

Authors wish to thank reviewers for their suggestions and remarks. We hope that enhancements will accomplish the requests and will be appreciated.

Response is reported in the attached file.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear,

the updated manuscript shows improvement over the first upload. In particular, it focuses on the guidelines for translating design requirements into topology optimization inputs and for incorporating topology and structure concerns in the early stages of the design activity. Together with the other changes, the change in Section 3 brings a real refresh. 

The manuscript that was first uploaded appears to have a serious deficiency. Given the topic and the sections presented, it sounds like a case study aimed at showing an application of topology optimization to solve a specific problem (design of an ancient statue), rather than presenting what is new about the current state of the art in topology optimization.
It was felt that it can replace all phases of the conceptual design process. Therefore, it was expected to provide explanations on how a single tool (topology optimization) can replace all these phases in the conceptual design process, and in the end, I proposed to reject the manuscript. 

However, the newly uploaded version of the manuscript sounds quite different to me in a positive and novel way, and considering the authors' response, it can be accepted in the present form.

Reviewer 3 Report