Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Railway vehicles run under dynamic operating conditions. The structural component most affected by dynamic loads is the bogie frame connected to the wheelset through the primary suspension and to the car body through the secondary suspension. This article provides a good approach to optimization of the bogie frame design.

The following points could help the authors to improve this article:

1.      Please add the finite element software used, e.g., ABAQUS.

2.      The element types should be mentioned, and mesh should be shown, especially at the critical areas.

3.      Please comment on the 3D elements vs shell elements.

4.      The fatigue performance before and after the optimization should be given in the Table format so that the readers can easily understand your approach achievement (at least the nominal figures would help).

5.      There are many research papers in the journal of Engineering failure analysis and rail transit (IMechE part F), which are directly related to bogie frames both in dynamic and stress analysis. Selecting some typical papers would enhance your article.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The current work titled "A new strategy for railway bogie frame designing combining structural topological optimization and sensitivity analysis" is interesting. I have the following suggestions and queries .

Line 26-27- “aiming to reduce air pollution generated by various types of land and non-land 26 vehicles”, are the authors taking about electric trains? Still many trains run on Diesel, please specify.

Line 38-39- “The present paper investigates the adoption of these numerical techniques, 38 applied on a railway bogie frame for metropolitan application…”, this should be after the relevant discussion on literatures and at the end of the introduction.

Line 50-51- “Several applications on car-body optimization oriented to lightweight design process, can be found in…”- this can be rephrased as “Many researchers have optimized the car-body oriented to light weight design process [10-12]. “. Similar changes can be made for other literature also in the introduction.

Line 155- “Each load case resulted complex because composed of several contributes”- this sentence is not clear, rephrase it.

Line 164- “made with a FE commercial software”-mention the software and the version.

Line 166-167- “has been modeled using a two-dimensional mesh consisting of SHELL elements with an average size of 10 mm and a minimum size of 3 mm”, what are the reasons behind choosing SHELL element and the specific size? Specify of there are any standards and also was there any grid independence study conducted?

Line 226-228- “Each contribution was tested at 25%, 50%, 75%, and 100% of the value required by the reference standard. This approach allowed for the consideration of realistic variations in the loading conditions to which the bogie frame could be subjected, as well as verifying the linear behavior of the calculated outputs.”-Are there any references to validate this, please specify.

Line 371-373- “Thanks to the manufacturing constraints introduced, the result provided by the optimizer was highly predisposed to production through sand-casting.” Avid using such sentences in a technical paper, please rephrase.

Line 394,395- “To conclude the activity, the innovative frame was tested both statically and under 394 fatigue conditions in accordance with the reference standard…”- Mention the standard here.

Finally please indicate how the validity of the simulations are done?

Comments on the Quality of English Language

The quality of English is decent, however I feel there is room for improvement and authors are requested to make use of Grammar correction tools to further improve the manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Authors have presented the optimization strategy for more robust bogie frame design with sensitivity analysis. The produced methodology and subsequent results succinctly validate the outcome. The different load cases and therefrom sensitivity analysis support the obtained results. Overall, the manuscript is well written and presented to justify the research at hand. Obtained results are also sufficient to derive the conclusion. However, there are a few minor concerns with the manuscript.

The literature review performed is not sufficient and up to date for any comparative analysis, which leads to concern on methodological validation.

A brief paragraph can be included at the end of section 1, describing the manuscript organization.

Authors kindly check the use of model/modal at places.

Comments on the Quality of English Language

Minor editing is required. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf