A Cross Electro-Mechanical Impedance Method Using a Distributed Piezoelectric Array for Bolt Loosening Detection

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

This article presents a detailed study of bolt loosening detection plates using a novel method.

The introduction is clear and relevant to the proposed work. From a state-of-the-art perspective, it provides a detailed analysis of existing research; however, it fails to mention the limitations of different methods proposed by other authors, which makes it impossible to clearly identify the degree of accuracy of the proposed method compared to other models.

Regarding the proposed methodology, it is important to highlight that it is well-designed; however, it could be improved by including key elements for understanding its development, such as the standard deviation of the measurements, cycle variability, and the method used to measure torque.

From the perspective of the numerical simulation performed for model validation, it presents important results. However, it is necessary to incorporate parameters that allow for a better understanding of how the numerical model was developed, such as: the type of elements used, the number of elements, mesh size, mesh sensitivity analysis, and determination of the friction effect, among others.

Finally, the discussion and results are well-presented; however, the limitations of using this model and its comparison with previously proposed models should be explored in greater depth.

Regards

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Journal : Applied Sciences

Title : A cross electro-mechanical impedance method using a distributed piezoelectric array for bolt loosening detection.

Authors: Lijun Yang, Wei Yan * and Dong Xuan

 

This study presents a new bolt loosening detection method based on the cross electro-mechanical impedance (EMI) technique. By comparing admittance signals obtained from a distributed piezoelectric array, the researchers evaluated different bolt tightening states through experimental analyses and numerical simulations. The results show that cross admittance signals exhibit higher sensitivity than drive-point signals, allowing for more accurate identification of both the severity and location of bolt loosening. Thus, this approach significantly improves the performance of EMI-based structural health monitoring.

The article presented by the authors is well written and well structured. A few minor questions could be useful to further improve the quality of this excellent work:

1. What is the role of the RMSD damage index in assessing bolt loosening, and how is it normalized before analysis?
2. As shown in Figure 1, how does it illustrate the principle of cross-admittance measurement between two piezoelectric sensors?
3. In Figures 4 and 5, how can the evolution of the conductance curves be explained when the bolt torque decreases, and what can be inferred from it?
4. By observing Figures 6 and 7, how do the RMSD values vary depending on the sensor position, and what do they reveal about the localization of the loosening?
5. How can the finite element method (FEM) simulations, illustrated in Figures 20 to 22, be explained to validate the experimental results concerning the detection and localization of bolt loosening?

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

In this research work, the authors developed a novel approach based the cross electro-mechanical impedance (EMI) technique for monitoring bolted joints to enhance structural safety and durability. The method is tested by numerical simulations (FEM) and validated experimentally using a distributed piezoelectric array.

 

 

This paper is interesting and it falls with the journal topics. It proposes an original method to monitor bolted joints. The work is well structured and all results are discussed accurately and justified.

 

Before suggesting the acceptation of the paper, I have the following comments and questions for the authors:

 

• Please give information about the type of PZT transducers and their choice?
• How the transducers were bonded to the studied samples?
• Please improve the quality of tables 1 and 2.
• In the caption of tables 1 and 2, I suggest to replace the word “coefficients” with “properties”
• Could you please give an idea about the computation time?
• Why the simulations’ results are not compared with the experimental ones? Please give the comparison.
• What is the effect of the material used to bound the transducer to metallic the structure?
• Have you compared the results of your method with those obtained using traditional methods existing in the literature?
• What are the limitations of the proposed approach?
• How the number of utilized transducers is chosen? Is there a minimal number / optimal number particularly for large structures?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

This article contains the necessary modifications for its publication.