Design and Simulation Analysis of a New Type of Assembled UHPC Collision Avoidance

Round 1

Reviewer 1 Report

Minor revision regarding tables shape and font:

Tables 1 and 3 should be revised, eliminate the interior horizontal lines and values should keeping the same font.

Author Response

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Reviewer 2 Report

This paper discusses about the performance of the new type of assembled UHPC anti-collision device based on the analysis result using finite element model. I considered that this work required efforts, time and costs, which is not easy to conduct by other research group. The result is considered important for engineer in the design of anti-collision device. However, the manuscript should be improved, because lack of detail information regarding the simulation and model. My comments regarding the manuscript are as follows.

1. Captions of Figure 4 and Figure 5 should be No.2 and No.3 box respectively.
2. Line 133: How did you decide the number of elements in the FE model? Did you conduct a convergence test to obtain the optimum one? Please provide the details of the decision process regarding the number of elements.
3. Line 150: Please provide reference for the parameter value of Mooney-Rivlin rubber model used in the rubber materials.
4. Table 1 is messy and blurry. Please check it again.
5. Line 160: I cannot understand what kind of test specimen was used in SHPB test and what kind of FE model was used in the reconstruction simulation shown in Figure 9. More detail explanation should be provided.
6. Please provide reference for parameter values listed in Table 2.
7. Please use “×” instead of “*”.
8. Line 225: Please provide reference for parameter values of the material model.
9. Line 269: Please provide reference for the friction coefficients.
10. Figure 33: What kind of stress? Please provide that information on the figure along with unit.
11. It will be useful, if you can provide information about the computational environment (workstation) and the calculation time for this simulation.
12. Line 289 and Line 412: Conditions 1, 2, 3 were used several times for different conditions and different simulations, that causes confusion. Different names should be used for example: condition A1, A2, …, B1, B2, …
13. The simulation result shows a good performance of the anti-collision device. However, it should be verified and validated against experimental result. How can you sure that the result of the simulation is correct and reliable?

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The paper describes a new design for a device that can protect both ships and bridges in the unfortunate event of a ship-bridge collision. The authors claim it has significant advantages over existing versions. The authors use explicit FEA to analyze the performance of versions of the design. They compare energy absorption and damage evolution between the versions to optimize design parameters.

Whilst the computation has been set up and done well, the lack of validation for the results (except for an impact test mentioned on Fig. 9 for concrete performance) will be of concern to anyone wishing to use the results for design.  This is because there are several assumptions used in the simulations about material behaviors, properties, friction coefficients, etc. Hence, the limitations of the current work must be clearly stated. Also, in Conclusions, it must be clearly stated that the results have not been field-tested or validated using experimentation.

GENERAL

1. There is significant scope for the English language to be improved. For instance, in the opening paragraph (under Featured Application’), on line 11, the word ‘I’ should be replaced with ‘we.’ Similarly, there are many other instances where the grammar is incorrect. The Abstract, however, appears to be an exception and is generally well written.
2. There are instances where the wrong message is given. As an example, how can an ‘anti-collision’ device be effective ‘in the event of a ship-bridge collision’ – line 29, page 1? It is better to use the phrase ‘collision avoidance’ in place of ‘anti-collision’ (including in the title).
3. Again, on lines 64-65, the authors say, ‘In this paper, a preliminary design scheme of an assembled UHPC anti-collision device is 65 presented.’ It is not clear how this preliminary design is related to the design of an existing bridge (lines 7-72).
4. In lines 9-12, the authors attempt to claim their design is being used to protect an actual bridge in China. More clarity is required in the language since it is unlikely that the design of the actual device being used was based on a purely numerical study as this.
5. There is also scope to be less wordy. For instance, in the first line (line 34, page 1) of the Introduction paragraph, the first words are unnecessary.
6. There is also a need for careful copy-ediing. For instance, there is a word ‘collisionshave’ on line 38, page 1.
7. Were any of the model results validated with experimental data? It is necessary to do so since several assumptions (material properties, friction coefficients, rubber behavior model – Mooney Rivlin, strengthening plastic model – line 219, ship material behavior, contact definitions, etc.) have been used in the computation. Only a successful validation can provide certainty that the predictions may be believed.

SPECIFIC

1. Lines 139-141 – What values of the friction coefficients were used? What was the sensitivity of the accuracy of their values to the final results of energy absorption and damage evolution?
2. Lines 146-147 – What was the threshold strain that was selected for element removal (is it 0.01 mentioned on line 148)? Was this validated with experiments? If not, a suitable reference must be provided from which 0.01 was taken.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Thank you for the detail information and the revision. The manuscript can be published now.

Author Response

Reviewer 3 Report

The authors have made most of the changes requested. However, they have omitted addressing one major criticism around the lack of validation of their model.

The authors must:

(1)  Mention that their model is yet to be validated in the Discussion as well as at the outset of the Conclusions (to signal to the reader that the results from the present model need to be viewed in that context), and

(2) The word 'anti-collision' (which was replaced by 'collision avoidance' in the majority of cases) still exists in parts of the manuscript (e.g. Conclusions). this must be fixed. 

Once these are done, the manuscript may be accepted for publication. 

Author Response

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Author Response File: Author Response.docx