Modeling and Characteristic Analysis of Combined Beam Tri-Stable Piezoelectric Energy Harvesting System Considering Gravity

Round 1

Reviewer 1 Report

The paper entitled “Modelling and Characteristic Analysis of Combined Beam 2 Tri-Stable Piezoelectric Energy Harvesting System Considering 3 Gravity” presents an interesting study of an energy harvesting resonator base excited and subjected to magnetic force effect in the tip of a not straight-shaped cantilever beam. Experimental and theoretical studies are presented, along with a wide study of it. However, the authors need to address some open questions in their paper.

1 – Why did the authors choose that kind of shape for the cantilever beam? What is the motivation and what is the difference between it and a straight cantilever beam with a magnet as a proof mass in the tip?

2 – I see that the authors did not account for the elastic properties of the cantilever along the length in the developments of the equations of motion, which is EI*integral(w’’). They provide a stiffness approximation as Eq. (4), but it is not clear if the stiffness relation is due to the magnetic field only or else. Can you please elaborate? Even though, this makes Eq. (9) unclear.

3 – Why did not the authors include the initial shape of the cantilever beam in their equations? This would yield better results due to the mode shapes formation. I believe it would be such as u(x,t)=w(x,t)+w0(x), where w0 would be a function of the initial shape of the cantilever.

 

4 – Please, include the piezoelectric material properties values that were used (e31,e33,d31,d33, and so if they are used).

Author Response

Dear Reviewer:

Thank you very much for your helpful comments. These professional comments are indispensable for improving the quality of the paper. Please refer to the attachment for our reply to the review report.

Author Response File: Author Response.docx

Reviewer 2 Report

The mathematical model of CTEHS is established considering the  gravity effect of the magnet, and the influences of the end magnet mass and the initial  vibration point on the system’s static bifurcation and output characteristics are  investigated by the method of numeric calculation, and experiments are carried out to validate the theoretical analysis in this paper.

I have few remarks related to manuscript:

1. Should be explained design of electrodes of PVDF in more details(Figure 1)

2. It is not clear how determined coefficient k1, k2 in equation (4)

3. Frequency of vibration vibration should be noted as "f" not "F"(it's used ussualy for forces) line 186 equation (18)

 

 

Author Response

Dear Reviewer:

Thank you very much for your helpful comments. These professional comments are indispensable for improving the quality of the paper. Please refer to the attachment for our reply to the review report.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors addressed all my comments very well and I believe the paper can be accepted for publication.

There is just one remark. I believe the e31 coefficient is negative due to the d31 coefficient value. Therefore, please address this in the final version.