Experimental and Numerical Methods for the Evaluation of Sound Radiated by Vibrating Panels Excited by Electromagnetic Shakers in Automotive Applications
Round 1
Reviewer 1 Report
1. I am not sure if section 4 is suppose to be 'Discussion' as stated or a conclusion. It looks like conclusion.
2. The simulation was tuned to a Young's modulus of 49.9 GPa which is quite low for aluminum. This value needs to be justified.
3. The paper provides results but lack on the discussion part.
4. Since the paper focuses on FEM, it would be good if the authors can provide contour diagrams of the simulation results too.
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Reviewer 2 Report
The reviewed paper concerns with the application of sound radiation produced by a vibrating vehicle panel displaced under an electromagnetic shaker. Aim of the research is the development of a numerical method for the prediction of the sound field outside the vehicle. The method’s validation is presented by comparing a laboratory experiment with a Finite Elements Method (FEM) simulation. A fully clamped rectangular aluminum plate was excited with a precision shaker, while a laser Doppler vibrometer (LDV) was synchronously recording velocity on a test grid, by means of an automatic scanning system. A FEM model of the plate was numerically simulated, to get velocity data on the same test grid.
The paper is definitely worth of publishing, however after minor revision.
1. The FEM simulation used by the authors is apparently based on the modal analysis, that should be stated explicitly somewhere in the introduction. It should also be mentioned that along with the modal analysis the explicit FEM simulation could be applied, which allows analyzing more advancd effects related to multiple reflection-refraction of sound waves in the panels, appearing different modes of Lamb, Love and SH waves etc., see (DOI: 10.1090/S0033-569X-06-00992-1; DOI: 10.3103/S0025654417060097).
2. The abs(d) in Eqs. (2) and (4) is excessive, since “the distance” between two points is always positive!
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Reviewer 3 Report
Dear authors,
At the beginning, I would like to congratulate you on a potentially very interesting paper with a comprehensive approach allowing you to see not only the numerical solutions to the problem but also very professionally performed experimental tests. Below I would like to point out some elements worth improving.
A) General remarks
1. A small comment about the affiliation list. It looks like the affiliations are not according to the journal template and some information is missing.
2. The article is not always clearly written and easy to follow. In some places, authors give the same information and even whole sentences multiple times.
3. The authors give relevant references which are linked to their study. It must be pointed out that the list of references is quite small and this is connected with a very poor introduction to the paper.
4. The abstract is well written introducing the basic overview of the paper. It is also written in a way that even a person not familiar with the topic can understand what the authors are proposing in their research. However, some sentences are problematic e.g. “The present paper deals with the second application: sound radiation produced by vibrating vehicle panels under electromagnetic shaker excitation.” Considering the previous sentence that the second application is active vibration control this sentence is false due to the fact that this is a specific experimental choice (using a shaker) of authors, not a real-life case. Construction of some information given in the abstract needs improving.
5. The introduction is poor and in fact almost not existing. The purpose of the introduction is to present the problem of the article and clearly present the overview of the state of the art in case of the topic and presented later on methods. In this case, the introduction is between lines 36 to 48. Later on, is basically an explanation of what was done. Additionally, that information was already presented in the abstract and is later presented in other chapters. This chapter has to be reconsidered. Problems of sound emission, mitigations etc in the cars (both traditional and new electric cars) should be presented. Additionally, the evaluation of testing methods needs to be extensive. The authors should introduce and present a traditional approach to experiments (excitation form shakers, modal hammers and measurements with accelerometers, and velocimeters) and a non-contact approach e.g using 3D LDV (e.g DOI: 10.1109/IDAACS53288.2021.9661060) or sometimes also useful method Digital Image Correlation, mainly for stress/strain/deformation measurements but also with the possibility of frequency response measurements (e.g DOI: 10.1007/978-3-030-47721-9_15)
6. Chapter 2 is well written. However please clearly state that only a single-point LDV measuring system is used. Additionally:
a. Was the effect (eventual error) of the head mounted on the fabricated moving system evaluated? No integration with e.g ground motion causing inaccuracies. The LDV heads usually have a mounting system to protect from those effects.
b. Was the same evaluated for the microphone? The way it is mounted may also detect some frequencies coming from the LDV head, electrical components etc.
c. No information is given on the LDV sensor, accuracy, or chosen acquisition parameters. Thus it is not possible to eventually cross-check the findings by other researchers.
d. The reviewer is not sure as far as other models of Polytec vibrometers like 3D ones they have a controller that allows connecting the shaker or a loudspeaker. microphone etc and control everything from Polytec applications. Why the authors have chosen to use zoom F8? It is not fully clear from the article.
e. Similarly, as far as reviewers' experience it is possible to use some Politec LDV software to do similar connections to FEM to cross-check the data. Some Polytec LDVs (not sure if this is the case for single point systems like the authors are using) allow integration with PolyWave Modal analysis post-processing suite and also to connect to FEM software like Ansys. Can authors give an explanation why they have chosen a different path? This is also not clear from the text.
7. The simulation methods are described in detail.
8. In case of results presentation:
a) Fig. 7 the text (axis) and legend are hardly visible. Please enlarge the font.
b) Fig.8 similar comment
c) Fig.9 similar comment
9. Chapter 4 is called “discussion” but in fact, this chapter is mostly conclusions without clearly stating the novelty (please improve). The “discussion” chapter does not exist at this point. This must be improved. Additionally, there is no such thing as the “next future” (line 286). In the whole article, there are a few places where common, not technical and inaccurate language is used. Please recheck the whole text.
B) Item remarks
Already stated in part A point 8.
Additionally, in Fig. 5 most things are not visible. Maybe enlarge some parts in additional windows (sensors and actuators).
C) Conclusions
The article is clear and interesting with no significant errors found in the research but with some questions that need to be answered. Both methodology and results acquisition is mostly correct. However, some changes have to be made in case of an explanation of the equipment used, and signal parameters. Moreover, some additional state-of-the-art analysis of modern modal analysis testing techniques has to be incorporated in the introduction. The article has potential after eventual improvements. At the current stage, the reviewer asks for major changes in those areas and will be happy to accept the paper after sufficient corrections.
Author Response
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Round 2
Reviewer 1 Report
I believe that the authors have addressed most of my comments well. However, before recommending for publication, I believe that the authors still need to justify the Young's modulus value used in the simulation which is quite low compared to the typical aluminum properties. Justify here does not mean that the authors need to perform an experiment. A simple source of reference that suggest aluminum/aluminum alloy can achieve a Young's modulus as low as 49.9 GPa would suffice.
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Reviewer 3 Report
Dear authors,
The reviewer has noticed significant improvements.
However, some aspects and the quality of the paper still can be improved, if no additional elements are asked to be improved by the other reviewer, the paper can be considered for eventual publication.
Best regards,
The reviewer
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