The Elastic Wave Propagation in Rectangular Waveguide Structure: Determination of Dispersion Curves and Their Application in Nondestructive Techniques

Round 1

Reviewer 1 Report

Accept

Author Response

Thanks for your observations and suggestions ,

Best Regards

Ignacio Iturrioz

Reviewer 2 Report

I would like to thank the authors for their thorough reworking of the manuscript. I feel the article can be published in the present form.

Author Response

Thanks for your observations and suggestions ,

Best Regards

Ignacio Iturrioz

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The authors present and interesting piece of work regarding wave propagation in prismatic waveguides. I have briefly checked the equations and seem correct to me. Thanks to the advanced manufacturing and testing techniques employed, I could advise for publication of this work in AS under the following conditions:

 

1)            The manuscript is well written in general, however I would encourage the authors to perform a careful proofreading of their manuscript for minor typos and inconsistencies (e.g. Two SAFE were implemented…).

 

2)            Figure 12 is probably the most interesting in the text, however no comprehensive discussion is provided as to why these divergences exist between the two sets of results. Moreover, the figure captions are incomplete and do not fully explain to the reader what information is presented within each figure.

 

3)            There are a lot of style inconsistencies within the text. Pages are not numbered (Why not?), however in what I see as page 18 there are at least 2 different fonts. Moreover, equations do not have variables in italic writing. Please make all variables in the text italic.

 

4)            Equations 2,3 are a bit confusing for the reviewer. I also generally find authors stingy with equation derivation and I would be more than happy to see more sub-steps in their derivation process when it comes to describing their formulation. Please do be more explanatory, especially with the theoretical part.

 

5)            Moreover, I find the quality of Figure 20 a bit poor. Please double check the quality of your eps files.

 

6)            52 references is a substantial number, however the authors will need to include additional ultrasound modelling techniques in their survey. It would be essential for the authors to cite previous work in the field, such as the one presented in:

 

Duan, W., & Gan, T. H. (2019). Investigation of guided wave properties of anisotropic composite laminates using a semi-analytical finite element method. Composites Part B: Engineering, 173, 106898.

 

Thierry, V., Brown, L., & Chronopoulos, D. (2018). Multi-scale wave propagation modelling for two-dimensional periodic textile composites. Composites Part B: Engineering, 150, 144-156.

 

Thierry, V., Mesnil, O., & Chronopoulos, D. (2020). Experimental and numerical determination of the wave dispersion characteristics of complex 3D woven composites. Ultrasonics, 106068.

 

and others.

Reviewer 2 Report

This article deals with the propagation of mechanical waves in rectangular section waveguides (with section of 15 mm by 5 mm) in the frequency range of 0 to 100 kHz. This work is theoretical, numerical by finite elements method and experimental. The computation of the structure dispersion curves is performed using three different approaches: analytical solutions, a method that combines analytical approaches with finite element methods called SAFE method, an experimental method with a piezoelectric transducer for the emission and 2 laser vibrometers to measure the wave displacement.

The state of the art is insufficient and the objectives could be better defined. This work could be interesting but could be improved: the introduction should be totally rewritten. I am very surprised to read in the introduction (lines 55-61) “The introduction should briefly place the study in a broad context and highlight why it is important. It should define the purpose of the work and its significance. The current state of the research field should be reviewed carefully and key publications cited. Please highlight controversial and diverging hypotheses when necessary. Finally, briefly mention the main aim of the work and highlight the principal conclusions. As far as possible, please keep the introduction comprehensible to scientists outside your particular field of research. References should be numbered in order of appearance and indicated by a numeral or numerals in square brackets, e.g., [1] or [2,3], or [4–60 6]. See the end of the document for further details on references.” I totally agree with this opinion which is probably that of a previous reviewer!

Authors should better clarify why their technique using Fiber Gratting Bragg cell is new.

This paper should be reworked and reread before submission: see for example lines 55-61, 190-191… Line numbers do not appear on pages 8 to 13 which makes it difficult to correct the article. Extensive editing of style is required.

The conclusion should be improved and rewritten too: the limitations of the method should be explained and the perspectives of this work are not presented.

To conclude, this article presents some results on a subject suitable for the Applied Sciences journal. I feel that manuscript should be reworked before acceptation.

Reviewer 3 Report

The submitted manuscript presents an investigation into how to determine the practical dispersion curves of a rectangular bar structure to identify the wave mode in the frequency range of 0-100 kHz. To estimate the dispersion curves, the authors used three theoretical methods such as the plate theory, the Euler-Bernoulli beam theory, and the Semi-Analytical Finite Element (SAFE) method. Experimental methods using two laser vibrometers and piezoelectric actuators were also investigated to verify the theoretical dispersion curves. Lastly, the authors discussed the Fiber Gratting Bragg (FGB) using discrete optical fiber sensors to capture the wave propagation in a rectangular bar structure and the associated finite element simulation results were presented to show the acoustic emission-based NDT method for identifying crack modes using the FGB technique. The authors concluded that the dispersion curves estimated by the SAFE method are more accurate than the other analytical methods and the simulation results are in good agreement with the experimental results.

However, the reviewer believes that the manuscript was written too poorly to convey the importance of the work and its major contribution to the field of NDT research using wave propagation. In addition, the reviewer thinks that the effectiveness of the SAFE method is already well known, and the presented experimental method is not new or advanced. Therefore, the reviewer suggests the editor REJECT the manuscript in the current form. The manuscript should be greatly modified to emphasize the importance of the research and the key contributions or findings of the presented research in comparison to previous publications in the field. Detailed comments of the reviewer are as follows:

The title can be confusing to the reader. Do the authors have any specific reason to use the word “prismatic waveguides” instead of using a rectangular bar/rod waveguide structure? The footnote number 4 should be corrected to 3. The last paragraph of the introduction section is very hard to understand. The authors should double-check the content and revise it to highlight the main objectives of the study. Inline 101 on Page 3, the author should give the reason for focusing on a specific frequency range of 0-100KHz. In subsection 3, did the authors use two PZTs with two different polarizations (transverse and longitudinal)? If so, in order to clarify the mechanical properties of the PZTs, it is recommended to modify the relevant text using a table. In Fig.7, it is difficult to distinguish between the two plots. It is recommended to use a colored line in one of the plots. In Fig.8 (a) and (b), did the authors use two different PZTs to generate a specific mode of interest? Please clarify the experimental details. In Fig. 9, where is the scan line to acquire the wave propagation results shown in Fig. 9 (a)? Also, when is the time point to have the wave propagation results in the figure? The scan line and the time point should be indicated in the figures. In Fig. 13, why did the plot have a different range of the x-axis? Please double-check the plot. Also, the SAFE simulation results should be indicated in the legend. The NDT application section is very weak compared to the section that determines the dispersion curves. It is recommended to strengthen or remove the section. In Fig. 19, “Modo” should be read as “Mode”.