Parameter Identification for Structural Health Monitoring with Extended Kalman Filter Considering Integration and Noise Effect
Round 1
Reviewer 1 Report
The paper studied the dynamic damage identification for a five-story steel frame by using extended Kalman filter method and identified the decrease of stiffness successfully. A numerical model has been established to study the effect of the integration methods and noises.
The comments are as follows:
1. In line 306-308, Figure 10 includes three cases, but authors haven’t descripted the difference. Please consider add a description.
2. Please consider including the accelerometer measurement direction for Figure 11.
3. In Table 2, please consider add a description for “Damage degree”.
4. In line 323-329, Please consider including a description of “Measured stiffness” for Table 2.
Author Response
Manuscript ID: applsci-384660
Title: Parameter identification for structural health monitoring with extended Kalman filter considering integration and noise effect
Authors: Liyu Xie , Zhenwei Zhou , Lei Zhao , Chunfeng Wan , Hesheng Tang , Songtao Xue*
We would like to express our sincere appreciation to you for your valuable comments on our paper (Manuscript ID.: applsci-384660). Appropriate revisions have been made to our manuscript to address your concerns, and all these revisions have been tracked in the revised manuscript. Point-to-point responses to these comments are provided below to explain our revisions.
Reviewer’ comments:
The paper studied the dynamic damage identification for a five-story steel frame by using extended Kalman filter method and identified the decrease of stiffness successfully. A numerical model has been established to study the effect of the integration methods and noises.
Point 1. In line 306-308, Figure 10 includes three cases, but authors haven’t descripted the difference. Please consider add a description.
Response 1: Thanks for the constructive comment. We have made a lot of revision in our experimental part, and the number of the figure has also changed. The following sentence has been added to descript the “figure 10”（Figure 11 in the revised version） in revised manuscript:
“Three different damage cases are considered with the corresponding experimental models shown in Figure 11. Case 1 represents the intact case with no damage occurred. However, in case 2 and case 3, certain extents of damages are introduced to the 5th and 4th story, respectively”
Point 2. Please consider including the accelerometer measurement direction for Figure 11.
Response 2: Thanks for the constructive comment. In this dynamic test, the accelerometer is mounted on the slab of each storey to measure horizontal acceleration. To address the reviewer’s comments, the sentence has been added to the following:
“Accelerometers are mounted on the slabs of each floor to collect the horizontal accelerations.”
Point 3. In Table 2, please consider add a description for “Damage degree”.
Response 3: Thanks for the constructive comment. The following sentences had been provided to explain “Damage degree”
“For the intact case (Case 1), all columns have the size of specification 1. Structural damage is then introduced by replacing the initial columns with the thinner columns (specification 2 or 3) so that the story stiffness will be decreased. The details of the three damage cases can be found in Tables 3. Actually, the damage degree, which is defined as the reduction extent of the story stiffness in this paper, of each case is 0%, 10.5%, 22.7%, respectively.”
Point 4. In line 323-329, Please consider including a description of “Measured stiffness” for Table
Response 4: Thanks for the constructive comment. Considering the manufacturing error of the steel bars as well as the installing effect, there is a certain error between theoretical stiffness and actual stiffness in this test. However, to correctly evaluate the damage identification performance, actual stiffness should be used for analysis. In order to measure to actual stiffness of these steel columns, the static test method was used to determine the actual stiffness of steel columns. That is why we list a “Measured stiffness” in this Table. In order to further address the reviewer’s concern, the following sentence has been added to descript the “Measured stiffness” in revised manuscript:
“Columns with three different sizes are considered, consistent with the three damage cases. Columns’ parameters are tabulated in Table 2. Considering the manufacturing error of the steel bars as well as the installing effect, the static test method is further made to determine the actual story stiffness with steel bars of three different sizes. In each story, there are four columns and their sizes are the same.”
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Recommendations:
check/improve some English expressions
the discussion of results should be revised. For example, in figures 3-to-6 (and related text comments), it would be beneficial to replace the legend definitions with some short labels. This will facilitate the comparisons discussion and the readability of the paper
figure 4 and figure 6: why the x-axis values do not start from 0? A uniform number style / format should be used
figured 5 a-to-d: the plots cannot be directly compared, because the y-axis limits are not the same. The plots should be harmonized.
the same comment is for figures 7 a and b. And figure 8,9. Revise the axis limit values
general comment: it is suggested to extend the experimental section, since actually provides a valuable input to the full paper
the section of conclusions should be revised. Try to add quantitative comments / data in support of major outcomes of the study. What's added to existing literature? Why this paper should be published? etc
section 4.1: add more details about the acceleration sensors and the collected measures. Please also refer to: https://www.mdpi.com/2224-2708/7/3/30
figure 10: cases 1 to 3 should be better defined. Where's damage? What's the difference between these 3 configurations? Add comments
the full paper collects 30 equations, which is a number more appropriate for a technical report. Try to remove at least part of them, or place some of them in a final annex. In this manner, the readability of the paper will be improved
Author Response
Manuscript ID: applsci-384660
Title: Parameter identification for structural health monitoring with extended Kalman filter considering integration and noise effect
Authors: Liyu Xie , Zhenwei Zhou , Lei Zhao , Chunfeng Wan , Hesheng Tang , Songtao Xue*
We would like to express our sincere appreciation to you for your valuable comments on our paper (Manuscript ID.: applsci-384660). Appropriate revisions have been made to our manuscript to address your concerns, and all these revisions have been tracked in the revised manuscript. Point-to-point responses to these comments are provided below to explain our revisions.
Reviewer’ comments:
Point 1: check/improve some English expressions
Response 1: Thanks for the suggestion. We have read throughout the manuscript and carefully polished it.
Point 2: the discussion of results should be revised. For example, in figures 3-to-6 (and related text comments), it would be beneficial to replace the legend definitions with some short labels. This will facilitate the comparisons discussion and the readability of the paper
Response 2: Thanks for the constructive comment. Several discussions have been revised.
Point 3: figure 4 and figure 6: why the x-axis values do not start from 0? A uniform number style / format should be used
Response 3: Thanks for the suggestion. The x-axes of Fig. 4 and Fig. 6 represent the integration step. In this discussion, we aim to illustrate the tendency of relative error of the three integral methods of stiffness and damping ratio under different integration steps. In the revised manuscript, the x-axis has been changed to start from 0.
Point 4: figured 5 a-to-d: the plots cannot be directly compared, because the y-axis limits are not the same. The plots should be harmonized.
Response 4: Thanks and revised.
Point 5: the same comment is for figures 7 a and b. And figure 8,9. Revise the axis limit values
Response 5: Thanks and revised.
Point 6: general comment: it is suggested to extend the experimental section, since actually provides a valuable input to the full paper
Response 6: Thanks for the constructive comment. We have rewritten the experimental section. In the revised manuscript, experimental section has been extended with more description added.
Point 7: the section of conclusions should be revised. Try to add quantitative comments / data in support of major outcomes of the study. What's added to existing literature? Why this paper should be published? etc
Response 7: Thanks for the constructive comment. We have rewritten the conclusions according to your suggestion.
Point 8: section 4.1: add more details about the acceleration sensors and the collected measures. Please also refer to: https://www.mdpi.com/2224-2708/7/3/30
Response 8: Thanks for the suggestions. In order to further address your concern, we have extended the experimental section, some details about the acceleration sensors and data acquisition have been added.
Point 9: figure 10: cases 1 to 3 should be better defined. Where's damage? What's the difference between these 3 configurations? Add comments
Response 9: Thanks for the suggestions. Damage cases have been defined in the revised manuscript and some comments also has been added.
Point 10: the full paper collects 30 equations, which is a number more appropriate for a technical report. Try to remove at least part of them, or place some of them in a final annex. In this manner, the readability of the paper will be improved
Response 10: Thanks for the suggestion. On the basis of ensuring the integrity and rigor of the article, we have removed some equations in the revised version.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Some of the original requests have been taken into account, but not all of them have been properly addressed, and the final result is a revised manuscript in which the methods and assumptions need further details/justification.
The experimental measurements, for example, are strictly related and affected by instruments in use. Since a moltitude of sensors is available for dynamic measurments like the experiments summarized in the paper, at least some technical features of them should be mentioned.
In the original review report, it was also recommended to mention the paper:
https://www.mdpi.com/2224-2708/7/3/30
and others (free choice of the authors), so as to quantify the accuracy of the accelerometers.
Now the authors are further encouraged to act in this direction.
In addition:
the content of figure 16 is mostly impossible to read. The scale or aspect ratio of the chart should be definitely revised and enhanced. Bar values close to zero cannot be perceived / distinguished. Small labels reporting the actual value could be added, close to them. Also in this case, the final choice is given to the authors, but some efforts are required.
some corrections are recommended in language
section 4.2: it is still not clear how damage has been assigned / defined / applied / quantified. Please clarify. A simple schematic drawing could be also beneficial.
Author Response
Response to Reviewer Comments
Manuscript ID: applsci-384660
Title: Parameter identification for structural health monitoring with extended Kalman filter considering integration and noise effect
Authors: Liyu Xie , Zhenwei Zhou , Lei Zhao , Chunfeng Wan , Hesheng Tang , Songtao Xue*
We would like to express our sincere appreciation to you for your valuable comments on our paper (Manuscript ID: applsci-384660). Appropriate revisions have been made to our manuscript to address your concerns, and all these revisions have been tracked in the revised manuscript. Point-to-point responses to these comments are provided below to explain our revisions.
Reviewer’ comments:
Some of the original requests have been taken into account, but not all of them have been properly addressed, and the final result is a revised manuscript in which the methods and assumptions need further details/justification.
Point 1: The experimental measurements, for example, are strictly related and affected by instruments in use. Since a moltitude of sensors is available for dynamic measurments like the experiments summarized in the paper, at least some technical features of them should be mentioned.
In the original review report, it was also recommended to mention the paper:
https://www.mdpi.com/2224-2708/7/3/30
and others (free choice of the authors), so as to quantify the accuracy of the accelerometers.
Now the authors are further encouraged to act in this direction.
Response 1: Thanks for the suggestion. Some information of the Model 991C accelerometer is added, and the main technical features are also introduced in this revised manuscript. Furthermore, as the reviewer recommended, two papers about the accelerometers are referenced and mentioned in the experimental section.
Point 2: In addition: the content of figure 16 is mostly impossible to read. The scale or aspect ratio of the chart should be definitely revised and enhanced. Bar values close to zero cannot be perceived / distinguished. Small labels reporting the actual value could be added, close to them. Also in this case, the final choice is given to the authors, but some efforts are required.
Response 2: Thanks for the constructive comment. The figure 16 is modified as the reviewer suggested.
Point 3: some corrections are recommended in language
Response 3: Thanks for the suggestion. We have read throughout the manuscript and carefully polished it again.
Point 4: section 4.2: it is still not clear how damage has been assigned / defined / applied / quantified. Please clarify. A simple schematic drawing could be also beneficial.
Response 4: Thanks for the constructive comment. We have added some information for the damage defined and applied in this revised manuscript. To address the reviewer’s concern, a simple schematic drawing of the steel bars is also added.
Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
The additional modifications are appreciated.
As a minor suggestion, the authors are warmly encouraged to revise the legend fo few plots. For example Figure 6 or FIgure 18, etc. All "THE" terms must be removed.
This correction can be implemented during the production process, so I'm confident it will be finalized and I recommend the publication of the paper without re-review of the draft.
