Numerical Identification of Material Model Parameters of UHPFRC Slab under Blast Loading

Round 1

Reviewer 1 Report

The manuscript describes an interesting method for the identification of UHPFRC under the blast.

In my point of view, this original research was not presented properly. First of all, the is a lack of a general comparison of the results given by other authors from similar tests, e.g. deflection comparison for the different charges. 

There are numerous papers with similar experiments. On the other hand, the LS-Dyna benchmark case should be presented clearly before the submission to the simulation set.

The above two points cross out this work at this point from the submission.

Author Response

Dear reviewer,

Thank you for your review, remarks and your help. We tried out best to reflect your remarks as well as possible in the new version of our manuscript.

Because there was moderate number of revisions needed in our manuscript on the initiative of reviewers, we attached our revised manuscript with all the revisions and history of the revisions (in the .doc format) together with this response.

 

Kind regards

Authors

 

Authors`s Respose:

1. In my point of view, this original research was not presented properly. First of all, the is a lack of a general comparison of the results given by other authors from similar tests, e.g. deflection comparison for the different charges. 

 

• The comparison with other authors was added into the paper together with Table. 5 (Chapter 3). Table 5 contains comparison of the deflection from similar blast, i.e., concrete material slab of similar dimensions loaded by similar amount of explosive from similar blast-off distance. Table 4. was added to present the parametric trial and error experimental measurements carried out by the authors.

2. There are numerous papers with similar experiments. On the other hand, the LS-Dyna benchmark case should be presented clearly before the submission to the simulation set.

• Chapter 5 – computational model was substantially expanded with more specific description of the computational model creation, together with the description of the experimental measurement (Chapter 3) on which bases the computational model was created.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

Introduction prepared not in accordance with generally accepted standards. Also, the optimization process is described at the university level.

You can not refer to local, national standards in an international article.

Concrete is not a homogeneous material, so inference from 2 or 3 samples is unacceptable.

There is no information about the number of blast wave experimental tests.

Most significantly, the concrete model is dependent on many parameters which makes it possible to adjust one experiment very well. The experimental tests should be carried out for at least several charge distances from the sample and several charge masses.

In the article, use generally accepted size designations, such as "n" for Poisson's ratio.

Author Response

Dear reviewer,

Thank you for your reviews, remarks and your help. We tried out best to reflect your remarks as well as possible in the new version of our manuscript.

Because there was moderate number of revisions needed in our manuscript on the initiative of reviewers, we attached our revised manuscript with all the revisions and history of the revisions (only in the .doc format) together with this response.

 

Kind regards

Authors

 

Authors` response

1. Introduction prepared not in accordance with generally accepted standards. Also, the optimization process is described at the university level.

• The introduction and abstract were modified with added refences.
• Optimization process mentioned in the paper was used in these ways due to its computational time effectiveness. Available References were added for supporting the usage of this method. Authors admit that there are many more methods implemented in the used software environment to their disposal and will continue to explore their possibilities.

2. You cannot refer to local, national standards in an international article

• New references in the paper were added accordingly to the EU standards (formerly referred standards were national implementation of these EU standards).

3. Concrete is not a homogeneous material, so inference from 2 or 3 samples is unacceptable.

• Authors admits that 2 or 3 samples are in general very low number for statistical processing of the data. Mechanical compressive strength tests were performed on 3 specimens, but references for other tests performed by the authors on the specimens of the very similar concrete composition were added to the paper for supporting the test results. Table 4 and Table 5 were added to the paper to support the experimental results. Tensile strength tests of the specimens were performed altogether on the 9 specimens.

4. There is no information about the number of blast wave experimental tests.

• Table 4 added to the manuscript to clarify the number and parametric experimental setup.

5. Most significantly, the concrete model is dependent on many parameters which makes it possible to adjust one experiment very well. The experimental tests should be carried out for at least several charge distances from the sample and several charge masses.

• Similar as the point 4, for these purpose Table 4 and Table 5 were added for supporting the evidence and results.
•  

6. In the article, use generally accepted size designations, such as "n" for Poisson's ratio.

• Designations were change accordingly in the revised paper.

Authors

Author Response File: Author Response.docx

Reviewer 3 Report

Dear colleagues,

I appreciate your research and I did some suggestions about minor English modifications and graphs in Figures 1 and 2. Also, I think you could give details of the reinforcement as the firm produces more grades.

 

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Thank you for your reviews, remarks and your help. We tried out best to reflect your remarks as well as possible in the new version of our manuscript.

Because there was moderate number of revisions needed in our manuscript on the initiative of reviewers, we attached our revised manuscript with all the revisions and history of the revisions (only in the .doc format) together with this response.

 

Kind regards

Authors

 

 

Authors`s response:

1. I appreciate your research and I did some suggestions about minor English modifications and graphs in Figures 1 and 2. Also, I think you could give details of the reinforcement as the firm produces more grades.

• English in the manuscript modified according to the recommendations.
• Added information about the fibres in the chapter 2 (lines 259-262)
• Two Pictures on the page 8 were removed. Authors completely agree with your observation and explanation, in the future, we will focus on this matter during the testing and data evaluation. But did not want to modify the raw data and subsequently, these figures were more of less illustrative. The more important more from these curves are the peak tensile strength which are stated int the Table 3 anyway.
• Fracture energy remark are the only remark authors dare to let unmodified (original line no. 413) as the authors are convinced that this parameter is fracture energy, one of the important parameters of concrete that are also used in numerical material models (specifically in Winfrith material model). Authors hope, that they are not mistaken.

Authors

Author Response File: Author Response.docx

Reviewer 4 Report

Overall, the structure of the paper is ok. However, you need to provide further details of the research need of this paper. You also need to add extra references to the paper to support your text with evidences. Some paragraphs are not very clear to me. I believe that you can improve it. Please also consider to increase the resolution of the figures. It was very hard for me to see some of the results. Please also add details of the numerical model used by LS-Dyna. I have attached your manuscript with all my comments.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Thank you for your reviews, remarks and your help. We tried out best to reflect your remarks as well as possible in the new version of our manuscript.

Because there was moderate number of revisions needed in our manuscript on the initiative of reviewers, we attached our revised manuscript with all the revisions and history of the revisions (only in the .doc format) together with this response.

 

Kind regards

Authors

 

Authors` response:

• Overall, the structure of the paper is ok. However, you need to provide further details of the research need of this paper. You also need to add extra references to the paper to support your text with evidences. Some paragraphs are not very clear to me. I believe that you can improve it. Please also consider to increase the resolution of the figures. It was very hard for me to see some of the results. Please also add details of the numerical model used by LS-Dyna. I have attached your manuscript with all my comments.

 

• Added evidence and references where needed on the bases of the remarks from the obtained pdf. References added on the line (from original pdf) 32, 35, 248, 249, 250, 395, 438..

Chapter 3 – details added to experimental setup together with comparison of the experimental results and comparison of these result with other authors (Table 4, Table 5 in the revised dociment).

• The bad resolution of the pictures happened on the side of the journal by converting original manuscript from .doc do .pdf. Not sure what can we do about it, but in the revised manuscript, pls refer to its .doc version as there can be found original figures and tables (however the work with this revised document will the whole revision history is clumsy).
• The numerical model description in Chapter 4 was substantially expanded.
• Other comments and remarks from your pdf were reflected in the new revised version, to name a few – schematic setup of the experiment, fiber reinforcement description, yield conditions etc...

Kind regards

Authors

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The updated version of the manuscript is good enough to be presented in the journal.

Author Response

Dear reviewer,

thank you for your kind reviews and help. We are looking for our next cooperation.

PS: In attachment, we are sending the final version of our manuscript as result of the second round of revisions.

Kind regards

Authors

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

Introduction prepared not in accordance with accepted standards. The same description of the content of the articles as you presented does not apply.

I understand that LsDyna conference materials are very popular. However, the materials there are presented in a specific way that is not up to the standards of the rest of the publications. The names of cards are not used, but the names of physical or material models (l. 524).

When writing about the proper designation of Poisson's coefficient in the previous review, I also had in mind the other designations that appear in the article.

The article lacks data describing air and explosive or at least references to the literature.

No information on the size of the elements and their type or at least the number of integration points. A substandard description of the equation of state of the air. Over-simplification in the description of explosive as: material, description of detonation process, description of detonation products. Incompatible with accepted standards description of the interaction of material (concrete) with fluid (air, detonation products). (l. 791-811) 

Some of the figures are the same as in the paper [59]. Incorrect descriptions were also taken from this work.

 

The notation "…very small time step…" (l. 739) is wrong, instead there should be information about the CFL condition.

Author Response

Dear reviewer,

Thank you for your second round of review and your help. In this response, we indicate our answers to your remarks and questions. In the attached document, all revisions and their history can be found.

Revisions:

• Introduction prepared not in accordance with accepted standards. The same description of the content of the articles as you presented does not apply.
• Further modification of the introduction chapter, reduction of the description of the content of the articles, incorporation into the more fluent text.
• I understand that LsDyna conference materials are very popular. However, the materials there are presented in a specific way that is not up to the standards of the rest of the publications. The names of cards are not used, but the names of physical or material models (l. 524).
• Reformulated the description of the materials, settings etc. in the whole manuscript without using the specific notation or naming of the “cards” as they are used in LS-|Dyna (with couple of exceptions to the most important and described used “card” in the Chapter 5 - material model).
• When writing about the proper designation of Poisson's coefficient in the previous review, I also had in mind the other designations that appear in the article.
• All physical quantities corrected to their standard or usual designations
• The article lacks data describing air and explosive or at least references to the literature.
• Added reference to the used EOS and material properties of air and explosive
• No information on the size of the elements and their type or at least the number of integration points. A substandard description of the equation of state of the air. Over-simplification in the description of explosive as: material, description of detonation process, description of detonation products. Incompatible with accepted standards description of the interaction of material (concrete) with fluid (air, detonation products). (l. 791-811)
• Added details about the element types used.
• Added details about principles of EOS and material properties of air and explosive
• Added reference to the used EOS and material properties` values of air and explosive
• Added description about the process of fluid and structure interaction with reference.
• Some of the figures are the same as in the paper [59]. Incorrect descriptions were also taken from this work.
• Added references to used figures, description corrected according to original.
• The notation "…very small time step…" (l. 739) is wrong, instead there should be information about the CFL condition.
• This sentence reformulated without using time step specification

+ Other minor modifications based on the notes and recommendations of other reviewers, as indicated on the revision history in the included manuscript`s .doc document.

Reviewer 4 Report

The paper structure and content were improved. A lot of information and details that were missing from the initial manuscript are in the revised version. The extra figures added really facilitate understanding of the experimental set up. It would be nice to add a colorbar in Figs. 5 and 6. I may also be useful to add a stress plot in that section. I presume that the time-displacement curve in Fig. 7 is measured at the centre of the slab?

Author Response

Dear reviewer,

Thank you for your second round of review and your help. In this response, we indicate our answers to your remarks and questions. In the attached document, all second round revisions and their history can be found.

 

Revisions:

The paper structure and content were improved. A lot of information and details that were missing from the initial manuscript are in the revised version. The extra figures added really facilitate understanding of the experimental set up. It would be nice to add a colorbar in Figs. 5 and 6. I may also be useful to add a stress plot in that section. I presume that the time-displacement curve in Fig. 7 is measured at the centre of the slab?

• Added colorbars of the displacement (Fig. 5) and stress of the slab (Fig. 6)
• Added description of the time- displacement measured point (center surface node of the slab, according to the experimental setup)

+ Other modifications based on the notes and recommendations of other reviewers, as indicated on the revision history in the included manuscript`s .doc document.

 

Kind Regards

Authors

 

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

Dear Authors,

The description of the modeling of the blast wave propagation process and its effects on the structure (concrete slab) is already better, but unfortunately not yet sufficient. Please search and read articles analyzing analogous issues.

There is no information on how the equations describing the issue were integrated, including the adopted parameters.

In addition:

1. the "Jones-Wilkins-Lee equation of state" rather than the "Wilkinson Lee EOS" appears in the literature.

2. equation 10 is redundant. If the authors decide to leave it, the symbol indicating Pearson's coefficient should be the same

3. the content of Table 9 is inconsistent with the description

4. the last column of Table 6 is written in bold

5. a line must not start with a comma (l. 525, 531 …)

6. the information "(node no. 16907)" is unnecessary

 

7. the width of the columns in the tables must be better selected

Author Response

Dear reviewer,

Thank you for your third round of review and your help. In this response, we indicate our answers to your remarks and questions. In the attached document, all revisions and their history can be found. (together with the history of other minor corrections – grammar, typos, numbering of references etc.)

Kind regards

Authors

 

The description of the modeling of the blast wave propagation process and its effects on the structure (concrete slab) is already better, but unfortunately not yet sufficient. Please search and read articles analyzing analogous issues.

-Added to Chapter 5 theory and description of computation model: wave propagation modelling, interaction process, equations and principles of material definition witch corresponding references.

There is no information on how the equations describing the issue were integrated, including the adopted parameters.

-Added explanation of used EOS and material models and tables of adopted parameters.

In addition:

1. the "Jones-Wilkins-Lee equation of state" rather than the "Wilkinson Lee EOS" appears in the literature.

- corrected to Jones-Wilkins-Lee equation of state

2. equation 10 is redundant. If the authors decide to leave it, the symbol indicating Pearson's coefficient should be the same

- the first equation left out; symbols unified

(Original intention was to state both equations for Pearson coefficient, one for the whole population, one for sample).

3. the content of Table 9 is inconsistent with the description

- table symbolism in the table 9 slightly modified for higher clarity

(Table indicates the Pearson coefficient values for individual input parameter and objective function, i.e.,    is Pearson's correlation coefficient for aggregate size and Objective function. Analogously for other input parameters.

4. the last column of Table 6 is written in bold

- corrected

5. a line must not start with a comma (l. 525, 531 …)

- corrected in whole manuscript

6. the information "(node no. 16907)" is unnecessary

- information about the node left out

7. the width of the columns in the tables must be better selected

- width of the columns corrected where possible in the whole manuscript