Metallic Ribbon-Core Sandwich Panels Subjected to Air Blast Loading

Round 1

Reviewer 1 Report

The paper is interesting, but some parts of the manuscript require improvement and deeper explanations.

Comments to improve the manuscript:

1. Line 31-32: please add the relevant references (research papers and national requirements and codes (EU, USA, etc)). The literature is very rich in this aspect (antiterrorism standards and research for buildings and structures).
2. Line 35: should be ASCE instead of ACSE.
3. Literature review: Please take into account the papers published in the Journal of Sandwich Structures & Materials and other journals (i.e. TechnoPress, Eng. Structures), for example, https://journals.sagepub.com/doi/abs/10.1177/1099636217695651, https://journals.sagepub.com/doi/10.1177/1099636215626596?icid=int.sj-abstract.similar-articles.1 and others
4. Fig. 1: Please remove the insert from section (b).
5. Numerical modelling: The presented problem has a strong nonlinear character. How the authors modelled the nonlinearity?
6. Page 9 and 10: There are two Figures 5. Please revise the figure and relevant text. Besides, the figure presented on page 9 should be better described using (a) and (b) as well as clarify yellow (90) and black (0) inserts.
7. Discussion: The presented results of sandwich panels concerned the blast loading. However, these panels are also affected by other loads resulted from their normal operation in the building or structures. The combination of these loading can affect more adversely than presented in the study. Did the authors consider this aspect?
8. Discussion: The presented results also showed that the sandwich panels reach high plastic deformations. Can you assess the residual service life of such deformed panels? It would be interesting from a practical and safety (of structures) point of view.
9. The manuscript should be carefully check taking into account the author guidelines and quality of figures.

Author Response

response to reviewer 1 is attached. 

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper discusses the effect of various design parameters on the blast behavior of the Ribbon-Core Sandwich Panels (RCSPs) with a optimal scientific approach. The purpose to use results for guidelines is very important.

Globally it is well written and readable.

The Introduction should be improved added information about corrosion depth propagation, in particular inside the panel. Maybe, authors can discuss the approach followed by :

F. Rizzo, G. Di Lorenzo, A. Formisano, R. Landolfo, 2018. “A time-dependent corrosion wastage model for Wrought iron Structures”. ASCE's Journal of Materials in Civil Engineering, 2019, 31(8): 04019165

There are two Figures 5. Please change.

Figures 1, 5 and 5bis should be improved.

References should be improved.

I suggest to add a symbol list.

Author Response

response to reviewer 2 is attached. 

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper presents a numerical investigation on the proposed Robbin-Core Sandwich Panels (RCSPs) subjected to blast loading. The finite element modeling of sandwich panel under blast loading is developed employing ANSYS and verified by comparing with the recent test data. Parametric analysis with varying the parameters to evaluate their influence on the damage resistance of the sandwich panels are also carried out and discussed. In general, the idea showed in this study is interesting to researchers. However, the presentation of this manuscript is awkward and need more improvement before it can be considered for further process of publication.

Some following issues need to be addressed:

1. Although the FE modeling is described, it is not clear that how the authors model the contact between the front and rear plates with the core plate? The description of FE mesh size is also lack. Moreover, the explanation on how the authors simplify the boundary condition of the modeling is not presented. Please declare!
2. In their modeling, the authors use a reduced air domain with dimension of 70 mm × 70 mm, generated only over the center of the model, instead of covering all the model as the reality. The authors are required to explain why they decided to model such air domain size. Did the authors compare with the full model of the air domain and found that this such air domain size is reasonable to use?
3. It is suggested that Section 3 and 4 should be combined to be a Section, e.g.: “3. Proposed Sandwich Panels”. In the same manner, Section 5-7 should be combined to be a Section, e.g.: “4. Parametric Study” with several subsections, e.g.: 1. Effect of front and rear plate thickness; 4.2. Effect of the core dimensions.
4. Section 4:

• Since the deformation and damage of the structure are main issues that is interesting to researchers, we did not find any reason for the discussion on the velocity of the midpoint?
• Beside the comparison of residual deflection of the panel between the proposed and the conventional panels, is it expected that the damage of the panels also will be compared and discussed to show out the superiority of the proposed panels.

5. Please add a definition for “energy dissipation” discussed in Section 6 and 7? What is the meaning of “energy dissipation” in this work, how it effects to the damage resistance of the panel, and how to determine it?
6. According to this manuscript, effect of five different parameters, including the thickness of the front and rear plates; the thickness, angle of corrugation, and the height of the core on the damage resistance capacity of the panel are investigated and discussed. It is also expected that the authors can provide the efficient design of the panel, that is the best combination of different parameters.
7. The authors are required to check all Figures carefully.

E.g.:

- Fig. 1a: there is something wrong information existing on it

- Fig. 6: it is suggested that the left figures should be named as TZRC while the right figures should be TRC. Also, please check the vertical axis of Fig. 6a-left. And, ---back plt. does not show in Fig. 6b-left?

- Fig. 8: while in the previous figures, the continuous line is used for “front plt.”, it is used backwards in Figure 8, i.e. the dotted line is used for “front plt.”, making the reader very confusing.

- Fig. 9 and 10: please name a, b and c for the figures. (which one is Fig. 9a, and so on)

8. Many typos are found, requiring a thoroughly check

E.g.:

- Line 189: “…plastic strain rate. m is the thermal softening…” should be: “…plastic strain rate, and m is the thermal softening…”

- Line 207:  “Table 3” should be replaced by “Table 4”.

- Line 244: “…thickness (t_c) of 0.7 mm. the panel had the…” should be: “…thickness (t_c) of 0.7 mm. The panel had the…”

- Line 384: It should be begun with a capital letter.

9. Finally, the conclusion should be revised in the light of the revisions suggested above.

Comments for author File: Comments.pdf

Author Response

response to reviewer 3 is attached. 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

This manuscript is accettable in the present revised form.

Author Response

The response is attached  

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors responded and revised almost the issues that the reviewer recommended. However, there are few minor errors in the revised manuscript which should be corrected before publication as below:

1. Fig. 5: Please show which are Fig. 5a and 5b?
2. Some typos have not been corrected, e.g.: Line 378
3. While the authors mentioned that “The conclusion section has been revised”. It does not show any revision of the conclusion in the revised version.

Author Response

The response is attached 

Author Response File: Author Response.pdf