Development of Digital Twin for Intelligent Maintenance of Civil Infrastructure

Round 1

Reviewer 1 Report

This paper presented a intelligent maintenance method of civil infrastructure using digital twin. Here are some major comments:

1. The theoritical contribution should be clearly stated in the introduction part.

2. The comparison study with exisiting methods is missing.

3. Future works should be discussed in details.

Author Response

Dear Reviewer,

Thanks for the comments. Please see in the following responses to your comments. I have also attached a copy of the revised manuscript.

With kind regards,

1. The theoretical contribution should be clearly stated in the introduction part.

Thanks for the comment. More explanation is added to the introduction section to further explain the problems with existing methods in practice and how the proposed DT concept contributes in improving it. The additions is track changed and can be found in the revised manuscript in red colour.

2. The comparison study with existing methods is missing.

Many thanks for the comment. Section 4.4.1 is added to the revised manuscript to compare the proposed method with the existing methods and outline its advantages.

3. Future works should be discussed in details.

Thanks for the comment. Further explanation is added to conclusion to elaborate more on future work.

Reviewer 2 Report

Please find below some comments for this interesting paper. 

-The Introduction should be elaborated in order to include more details about the necessity of maintenance within the Industry 4.0 business model. Additionally, it is recommended to highlight the types of maintenance in order to better classify the proposed approach later. Please check below for interesting publications in the field of Industry 4.0 and maintenance:

a) Mourtzis, D., Angelopoulos, J. and Panopoulos, N., 2020. Intelligent predictive maintenance and remote monitoring framework for industrial equipment based on mixed reality. Frontiers in Mechanical Engineering, 6, p.578379.

b) Mourtzis, D., Angelopoulos, J. and Panopoulos, N., 2022. Design and Development of an Edge-Computing Platform Towards 5G Technology Adoption for Improving Equipment Predictive Maintenance. Procedia Computer Science, 200, pp.611-619.

c) Hallaji, S.M., Fang, Y. and Winfrey, B.K., 2021. Predictive maintenance of pumps in civil infrastructure: State-of-the-art, challenges and future directions. Automation in Construction, p.104049.

- Please highlight the research question of the paper. 

- Explain why this is considered an intelligent maintenance framework. By the time you am to develop a DT, the concept of intelligence is already included. 

- It is suggested to add the structure of the rest of the paper at the end of Introduction. 

- The content of Table 2 is very useful but should be validated with references. 

- Figure 4 should be presented in a more detailed and scientific manner including the necessary information and material flow as well as the communication protocols and the type of network between the physical and the virtual object.  

- Please ensue that all Figures are readable and of high quality (e.g., Fig. 7, 9). 

- Please summarize the results of the ANSYS in a Table. The presentation of Fig. 10-12 is useful but which is exactly the insight from the simulation? It is necessary to explain in a more detailed manner the digital twin. 
-How do you ensure the real-time data transfer? (e.g., 5G network)

- The authors state that Faults and causes of failure are identified using AI algorithms. Please elaborate more and present in a more detailed manner this important step.

- Add an Implementation Section to describe the hardware and the software that has been used in this case study. 

- There is no comparison with the State-of-the-art. Which is the novelty/advantage of the proposed architecture? 

- Please elaborate the References Style following the template of the journal. 

 

- Check the font size of the abstract. 

Author Response

Dear Reviewer,

Thanks very much for your valuable and constructive comments. Please see  below my responses to your comments. 

I have also attached a copy of the revised manuscript.

With kind regards, 

1. The Introduction should be elaborated in order to include more details about the necessity of maintenance within the Industry 4.0 business model. Additionally, it is recommended to highlight the types of maintenance in order to better classify the proposed approach later. Please check below for interesting publications in the field of Industry 4.0 and maintenance:
   1. a) Mourtzis, D., Angelopoulos, J. and Panopoulos, N., 2020. Intelligent predictive maintenance and remote monitoring framework for industrial equipment based on mixed reality. Frontiers in Mechanical Engineering,6, p.578379.
   2. b) Mourtzis, D., Angelopoulos, J. and Panopoulos, N., 2022. Design and Development of an Edge-Computing Platform Towards 5G Technology Adoption for Improving Equipment Predictive Maintenance. Procedia Computer Science, 200, pp.611-619.
   3. c) Hallaji, S.M., Fang, Y. and Winfrey, B.K., 2021. Predictive maintenance of pumps in civil infrastructure: State-of-the-art, challenges and future directions. Automation in Construction, p.104049.

Many thanks for the constructive comment and introducing useful references. More explanation about maintenance strategies and industry 4.0 capabilities in improving maintenance management practices is added to the introduction section (section 1). The suggested references were very useful and used and cited in revising the manuscript.

2. Please highlight the research question of the paper.

Thanks for the comment. Following questions are added to section 3.2 of the paper:

• Is application of the DT for infrastructure structural health monitoring feasible?
• What are the challenges in terms of interoperability?
• What sensor configuration is needed to collect required data? How to determine sensor locations?

3. Explain why this is considered an intelligent maintenance framework. By the time you aim to develop a DT, the concept of intelligence is already included.

Many thanks for the valid comment. The authors agree with the comment. As you mentioned, DT is an intelligent concept for monitoring a physical object’s performance. The word intelligent is a “given” when referring to the concept of DT. Therefore, using it doesn’t claim something which the DT concept can’t provide or commits to adding further capabilities to DT. We would like the title to read “making the concept of maintenance intelligent by using the DT concept” to someone who is not familiar with the DT.

4. It is suggested to add the structure of the rest of the paper at the end of Introduction.

Thanks for the comment. A paragraph explaining structure of the paper is added to the end of introduction (Section 1).

5. The content of Table 2 is very useful but should be validated with references.

Thanks for the comment. As suggested, references are added to the table 2 title

6. Figure 4 should be presented in a more detailed and scientific manner including the necessary information and material flow as well as the communication protocols and the type of network between the physical and the virtual object.

Many thanks for the comment. This figure is presented to illustrate the dynamic status of the DT concept and applications of digitalisation and synchronisation methods between virtual and physical worlds. More explanation is added to this section (section 4.2) to elaborate and clarify more.

7. Please ensure that all Figures are readable and of high quality (e.g., Fig. 7, 9).

Thanks for the comment. Figures 7 to 9 were replaced with better quality photos.

8. Please summarize the results of the ANSYS in a Table. The presentation of Fig. 10-12 is useful but which is exactly the insight from the simulation? It is necessary to explain in a more detailed manner the digital twin.
   -How do you ensure the real-time data transfer? (e.g., 5G network)

Thanks for the comment. More figures and tables are added within the content of the manuscript and at the end as appendices to provide more information on data collection, processing, and results of ANSYS. To monitor the structure changes under real-time loading conditions, ROM and sensor data were connected in an IoT platform. ThingWorx ptc was selected as IoT platform to connect the ROM (in Ansys Twin Builder) and sensor data (in Senscope software).

9. The authors state that Faults and causes of failure are identified using AI algorithms. Please elaborate more and present in a more detailed manner this important step.

Many thanks for the comment. The text is amended to prevent confusion. The faults are identified using data mapping of the real-time FEM model results against the design (expected) values.

10. Add an Implementation Section to describe the hardware and the software that has been used in this case study.

Thanks for the comment. Photos of hardware is added to the paper (Figure 13 within the text). Implementation results are also provided mostly in Appendices but some within the content of the paper as well (section 5.1).

11. There is no comparison with the State-of-the-art. Which is the novelty/advantage of the proposed architecture?

Thanks for the comment. Section 4.4.1 is added to the text to explain advantages of the proposed method compared to existing methods and other similar applications within the literature.

12. Please elaborate the References Style following the template of the journal.

Thanks for the comment. Referencing style is amended according to journal’s requirements.

13. Check the font size of the abstract.

Thanks for the comment. Abstract and the rest of paper is consistent in terms of font and size.

Round 2

Reviewer 1 Report

The reviewer has no further comment.

Reviewer 2 Report

The authors have revised the manuscript taking into consideration the comments raised by the reviewers. No further comments are raised.