Research on the Influence of Impedance-Layer Changes on the Protective Properties of Wave-Impedance Materials under Hypervelocity Impact
Round 1
Reviewer 1 Report
Thank you for the opportunity to review.
Here I provide my remarks.
It would be better to added the background of the research at the abstract: the purpose of the research, what is the gape in the knowledge your research should close and etc.
It would be better to added the shorted results of the research at the abstract.
The quality of some figures (e.g. 3, 4, 6, 8, 10) is under par and should be improved
Provide the prospects for the future research within the concluding section and explain what results will be achieved after these items.
Improve References. Must be about 30 cited articles or more. A large percentage of literature is over 5 years old. Add more the cited work from Applied Sciences.
The manuscript could be accepted after improve.
Author Response
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Author Response File: 
Author Response.docx
Reviewer 2 Report
This article is very interesting. Also the research which you make is interesting.
Please, explain me why you select and use this number for experience?
Also, please deepens the importance the whole research in practice?
Please correct and complete the minor mistakes!
Author Response
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Author Response File: Author Response.docx
Reviewer 3 Report
Wave impedance gradient material is a new type of space debris protective material with high kinetic energy dissipation, but there is still a lack of knowledge about the relationship between the distribution characteristics of impedance layer and the protective performance. In this study, the authors use theoretical analysis and numerical simulation methods to study the protective performance of wave impedance gradient materials under the hypervelocity impact, and obtain some valuable discoveries. However, the reviewer thinks that following concerns need to be addressed before a potential recommendation for publication.
(1) The writing needs much improvement. The authors need to carefully revise many grammatical mistakes and meaningless sentences to make the sentences more concise.
(2) Some references are cited incorrectly. e.g., " even the entire spacecraft. [1]" on line 33.
(3) Graphs need to be improved. e.g. The points marked by the red arrows in Figure 2 are not clear enough. “Table 1. This is a table. Tables should be placed in the main text near to the first time they are cited.” On line 161. The format of figures should be uniform (Figure 5, Figure 6, Figure 7, Figure 9, Figure 11).
(4) The numerical simulations are poorly described. It is highly required to clarify the simulations details. Such as the parameters of the EOS, constitutive models and failure models, as well as their sources. In addition, how to achieve adhesion between different layers? Node sharing or contact algorithm?
(5) The authors select different EOS and constitutive models for four materials. Why? In fact, the EOS and constitutive model has a great influence on the simulation results. Compared with the shocked EOS, the debris cloud particles simulated by the Tillotson and Puff EOSs are finer and more dispersed (Chinese Journal of High Pressure Physics, 18, 2004, 47-52). In addition, some studies have shown that the results calculated by the Grady failure model may be more consistent with the experimental results. Compared with the Grady failure model, the target is more difficult to fail with the maximum tensile stress failure model (Explosion and Shock Waves, 38, 2018, 949-956). What are the effects of different combination strategies on the simulation results and the conclusions of this paper?
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Thanks for your comments and the changes. The manuscript can be accepted.
Reviewer 3 Report
The authors have carefully revised the manuscript according to the review comments. The current manuscript has been greatly improved and can be published.
