Non-Stationary Wind Loading Identification for Large Transmission Tower Based on Dynamic Finite-Element Model Updating

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The topic presented by the authors is very interesting, the results they show are also interesting, however, the following observations are presented to improve the work:

In the manuscript it is not evident that the authors have carried out research and analysis of the state of the art, since it has very few bibliographical references. for example, in the introduction they only cite 2 references

In the proposal of this manuscript, the authors make use of ANSYS FE software, which of course is based on the finite element, but they do not give details of the tests and the use of the software functions with the finite element, which is very important. that all the details of programming and analysis be mentioned, because it is the main tool of this work

The authors show a field experiment with moderate wind, how do these tests translate to cases of tornado winds, with reliable results?

I think it is convenient for the authors to be able to validate their results, measuring the error and comparing with previous studies with conventional methods or strategies.

The authors mention the validation of the efficiency and effectiveness of their proposed method, however, in the results they show there is no evidence that demonstrates the efficiency and effectiveness of their proposal.

It is necessary to improve the quality of figure 15

In the response shown in figure 12, it would be good to also see the wind profile, to compare against the responses obtained.

Author Response

The topic presented by the authors is very interesting, the results they show are also interesting, however, the following observations are presented to improve the work:

Response: Thank you for your time and efforts invested in reviewing this manuscript. We hope the quality of the revised article can reaches the standard of a publication in the present journal.

 

In the manuscript it is not evident that the authors have carried out research and analysis of the state of the art, since it has very few bibliographical references. for example, in the introduction they only cite 2 references

Response: Thank you for the good suggestion. Accordingly, we have added significant citations [15-21] in introduction part. Now the number of the referred articles has increased from 14 to 21.

 

In the proposal of this manuscript, the authors make use of ANSYS FE software, which of course is based on the finite element, but they do not give details of the tests and the use of the software functions with the finite element, which is very important. that all the details of programming and analysis be mentioned, because it is the main tool of this work

Response: Thank you for the good comment. In this course of the dynamic calculation, the main software function employed is Newmark-β method whose details of programming and analysis are presented in an added appendix (Appendix 4). Thank you again. Suppose the added part is helpful for readers’ references.

 

The authors show a field experiment with moderate wind, how do these tests translate to cases of tornado winds, with reliable results?

Response: Basically, the ABL wind event according to the field measurement work does not have anything to do with the simulated tornadic event. However, they are both utilized to demonstrate the effectiveness of the innovative idea of utilizing the modal parameters measured on location to identify the wind loadings on the structure. The first case is targeted for the wind load magnitude identification; while the second case is for the wind load distribution identification. These are due to the fact that the ABL wind is of the deterministic velocity profile, while the tornadic velocity profile is highly time-varying. These are explained in the revised manuscript (see the part highlighted in green in conclusions part).

 

I think it is convenient for the authors to be able to validate their results, measuring the error and comparing with previous studies with conventional methods or strategies.

Response: The conventional method for load distribution identification basically relies on wind measurement using the anemometer and empirical velocity model. In accordance with the suggestion, we have added a new section (section 8) in the revised manuscript to comparison the proposed approach with conventional method in load distribution identification. The results suggest that better effectiveness is achieved for the load distribution identification method based on the flow measurement (traditional method) than for the method based on structural mode shape measurement (proposed method). However, the traditional method is subjected to the issue that accurate prior knowledge concerning detailed information of the tornado (the maximum tangential velocity of the tornado and the radium corresponding to the maximum tangential velocity) must be provided by the local weather station. Therefore, its applicability is limited with respect to the fact that the meteorological information of a tornado cannot be forecasted with up-to-date measurement techniques at present.

 

The authors mention the validation of the efficiency and effectiveness of their proposed method, however, in the results they show there is no evidence that demonstrates the efficiency and effectiveness of their proposal.

Response: In conclusions part, the relative errors of the identified tornadic velocity profiles using the proposed method (see Fig. 18) are additionally presented in Fig. 21, which is the evidence that demonstrates the effectiveness of the new method.

 

It is necessary to improve the quality of figure 15

Response: Thank you for the suggestion. The quality of Fig. 15 has been significantly improved.

 

In the response shown in figure 12, it would be good to also see the wind profile, to compare against the responses obtained.

Response: Thank you for the good suggestion. We have revised the figure accordingly. As shown in Fig. 12 which additionally compares the velocity samples calculated at 113-meter height against the responses so obtained at the tower top, the velocity samples and the response samples are of similar variation tendencies in both longitudinal and lateral directions.

Reviewer 2 Report

Comments and Suggestions for Authors

The paper presents a very interesting study on how to properly model using dynamic finite elements the structural stress to which a high-voltage power line tower is exposed in case of tornado winds. The novelty of the proposed modeling approach is the use of a transient tornadic load distribution identification method starting from a model correlation to atmospheric boundary layer winds. The proposed modeling approach is used to define/design a tower structural health monitoring (SHM) system. 

Some small remarks to the authors:

* The image quality of figure 1 should be increased.

* Figure 15.a  and 15.b are way to small, they should be increased in size.

Author Response

The paper presents a very interesting study on how to properly model using dynamic finite elements the structural stress to which a high-voltage power line tower is exposed in case of tornado winds. The novelty of the proposed modeling approach is the use of a transient tornadic load distribution identification method starting from a model correlation to atmospheric boundary layer winds. The proposed modeling approach is used to define/design a tower structural health monitoring (SHM) system.

Response: Thank you for your time and efforts invested in reviewing this manuscript. We hope the quality of the revised article can reaches the standard of a publication in the present journal.

 

Some small remarks to the authors:

 

* The image quality of figure 1 should be increased.

Response: Thank you. As we do not have a clearer image of the actual tower, we have decided to remove this figure. Thank you again for your concern.

 

* Figure 15.a  and 15.b are way to small, they should be increased in size.

Response: Thank you. The size of Fig. 15 has been increased accordingly.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed or clarified most of the observations, however, observing the actions carried out in the manuscript, two observations arise:

In reference 15 (Y. Zhang, W. Xu, G. Yuan, and Y. An, “The relationship between posttraumatic cognitive change, posttraumatic stress disorder, and posttraumatic growth among Chinese adolescents after the Yancheng tornado: the mediating effect of rumination,” Frontiers in Psychology, vol. 9, p. 474, 2018.) I do not find the relationship to the subject of this manuscript.

In the introduction, line 58, it is strange that they only cite the added references, 16-21. Without making a single change to the text.

Author Response

Responses to Reviewer’s Comments

 

We thank the editors for organizing the peer review for our article. Thanks also go to the Reviewer 1 for his/her valuable comments which are very helpful for us to improve the quality of our manuscript. We have carefully revised the manuscript according to the reviewer’s comments, and our point-to-point responses to reviewers’ comments are listed below.

 

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Reviewer 1

The authors have addressed or clarified most of the observations, however, observing the actions carried out in the manuscript, two observations arise:

 

In reference 15 (Y. Zhang, W. Xu, G. Yuan, and Y. An, “The relationship between posttraumatic cognitive change, posttraumatic stress disorder, and posttraumatic growth among Chinese adolescents after the Yancheng tornado: the mediating effect of rumination,” Frontiers in Psychology, vol. 9, p. 474, 2018.) I do not find the relationship to the subject of this manuscript.

Response: Yes, in fact, the reference little concerns the subject of the manuscript. Therefore, we have removed the reference.

 

In the introduction, line 58, it is strange that they only cite the added references, 16-21. Without making a single change to the text.

Response: Thank you for the comment. We have added the following text in the introduction part to order to properly cite Ref. [16-20]: According to Ref. [15], the time-consuming computational Fluid dynamics technique was utilized to generate the non-stationary tornadic wind load samples for the required dynamic analyses to take place. The authors in [16] developed a non-stationary analytical method for tornadoes acting on structures with reference to some early observations and calculated the tornado-induced dynamic responses of several buildings. Refs. [17-19] used an advanced small-scaled non-stationary vortex simulation facility to undertake physical tests of tornadic events. Ref. [20] suggested that both the tornadic load and the structural response are highly non-stationary due to the traveling nature of the tornado (see the part highlighted in red).