Unified Modeling and Analysis of Vibration Energy Harvesters under Inertial Loads and Prescribed Displacements
Round 1
Reviewer 1 Report
In my opinion the general merit of the article is high, it is correctly described, and the results are sufficiently interesting. However, the authors should make changes in the language and review certain expressions, on the other hand, in future revisions they should keep the numbering of the lines so that it is easier to indicate where the errors are detected. Another thing that must be taken care of is the homogeneous numbering of the equations.
Author Response
Point 1: However, the authors should make changes in the language and review certain expressions, on the other hand, in future revisions they should keep the numbering of the lines so that it is easier to indicate where the errors are detected.
Response 1: Language and expression have been reviewed and revised where applicable.
Point 2: Another thing that must be taken care of is the homogeneous numbering of the equations.
Response 2: The numbering of equations has been revised, it is now homogenous and follows the journal instructions.
Point 3: Does the introduction provide sufficient background and include all relevant references? Can be improved (x).
Response 3: The Introduction has been extended with additional associated bibliography. An additional reference, related to general modeling and comparison of PEH and EMEH, has been added in paragraph 3. Two additional references are explained in paragraphs 6 and 7. Although these two are aimed toward PEH, there modeling is of a general nature and therefore relevant to our work. Paragraph 1 and the last sentence av paragraph 5 have been clarified. The final paragraph of this section has been clarified to better convey how our work improves upon previous work.
Reviewer 2 Report
This work is very interesting for researchers. It provides scientific novelty and is correctly prepared.
Just some aspects of improvement that it would be convenient to modify:
Abstract. It is recommended to be more precise and concise, emphasizing the aspects of process improvement
Introduction:
It is recommended to rewrite it and provide more associated bibliography (it is very scarce) with current similar studies and works, published in research impact journals that justify the need to provide improvements in the methodology and that justify the objectives of the study.
Methodology:
It is recommended to explain and rewrite it more clearly. It is difficult to follow. The equations and variables should be better and more clearly explained. All formulas must be numbered according to the author's instructions of the journal (eg not eq 1 but better (1). It is recommended to improve the graphic quality of the figures. All equations, figures and tables must appear in the text.
Discussion. It is very interesting but it is recommended to synthesize it and rewrite it in a clearer way for the authors.
Conclusions. It is recommended to relate the conclusions with the objectives and results, justifying the verification of the method and its scientific utility to develop future applied prototypes.
References. A more rigorous and updated review is recommended , with reference to similar works published in high - impact journals
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 3 Report
This paper evaluated the characteristics of single-degree-of-freedom vibrational energy harvesters theoretically. In the calculation, the general expressions using dimensionless parameters that considers the resistance loss factor are derived and analyzed under inertial load and forced displacement. And, common general expressions were then used to compare the characteristics of piezoelectric and electromagnetic energy harvesters. The results provide new insights regarding optimal load, load power and power input to output efficiency and help in the choice of a suitable transduction method for a specific application as well as for the design of vibration energy harvesting devices. I would like to forward the following comments to the authors:
1. In the second equation (EMEH) of equations 4 and 9, the author should check the equations are correct.
2. In color contour figures, it is difficult to see black contour line on indigo or brown areas, it is good to use white contour line.
3. The author should explain what k is. If k and kM are the same, then the notation should be unified.
4. The range of k and xE varies widely from figure to figure, but the author should mention the value of k and xE used in standard vibrational energy harvesters.
5. In figure 6, the author should explain more on the result, especially, why the results of xE = 0 are discontinuous at k = 1.
6. In equation 18, the author wrote "We can see then that the expression for efficiency allows for close to 100% efficiency if xE is negligible and 2g/Qh >> 1.", however for GOptLoad ≈ 1, it must be 2g/Qh << 1. The author should check it.
7. In chapter 3, there is an explanation of the results, but little comparison or discussion. Conversely, in chapter 4, there is little result to support the discussion. Therefore, the authors should link the results and discussion.
8. I can find some mistakes. Such as, the subscript (Fig. 2 Right Rp => Rp), the missing of the equation number (Eqs. 2 and 3), the discrepancy in values (Fig. 6 h = 0.1 or 1), the overlapping of the equation number on the text (Eq. 16), the error of the referenced figure number (Section 3.3 line 3 "compare figure 12 with figure 7" => "compare figure 12 with figure 13"), number that do not exist in the reference (17).
Author Response
Please see the attachment.
Author Response File: Author Response.docx
