Impact-Rubbing Dynamic Behavior of Magnetic-Liquid Double Suspension Bearing under Different Protective Bearing Forms
Round 1
Reviewer 1 Report
The paper deals with a modern suspension bearing where a liquid with specific magnetic properties is implemented.
Critical comments on the paper
1. The authors implemented analytical model and later applied a numerical scheme to solve it. The model consists of a set of equations where values of predefined mechanical and electrical parameters were assumed. In my opinion this is a weak point of the presented method. How the authors determine the value of the parameters. The data set presented in table 1 seems too ideal and they are constant (stable). For example, why the gravitational acceleration is equal 10 m/s2. What does it mean “Rotor quality” – it is (probably) mass of the rotor.
2. The authors applied the known model. Its form is modified by the values of the parameters. In this way some failures of the system were mapped. The presented results of numerical analysis do not validate using other method or experiments. The authors discussed only results of computations. In my opinion, this is a significant methodological error. The authors should confront the obtain results with other method or with real signals. Unfortunately, there is no analysis in the paper.
3. The presented data analysis is qualitative rather than quantitative. The figures 9 – 15 are small and their form does not allow for comparison and quantification. The authors shortly describe the signals and system trajectories. The critical values are presented. No signal metrics, coefficients are not calculated.
4. The discussion of the presented results is very poor. The conclusions are short and trivial. The evaluation of the results of the different variants is presented in the table 2 and it is very general. The use of adjectives (e.g. short, shorter, …) does not give clear technical information.
5. Some suggestions are written in the appended file.
Comments for author File: 
Comments.pdf
Author Response
Dear Reviewer:
I am very glad to receive your review report. In view of your suggestion, I put forward the following solution.I hope these changes can meet your expectations.
To the suggestion 1: (1). The table 1 provides a list of the Initial designed parameters of the bearing, which provide the foundation for the numerical simulation. During the simulations, there will be some changes in specified parameters, such as initial unilateral clearance, oil supply pressure, etc. But these changes were to study the influence of these parameters on the bearing system. Therefore, we need to take the way to control the remaining variables, that is, the remaining variables adopt the initial designed parameters of the bearing system in table 1. (2). The gravitational acceleration is equal 10 m/s2 is to make the analysis of the system resultant force in the following figure more convenient and concise. Otherwise, the same gravitational acceleration is used in the three systems, which does not affect the conclusion of the overall research and analysis. (3). We changed Rotor quality into Rotor mass in table 1.
To the suggestion 2: In this paper, the impact-rubbing dynamics of electromagnetic bearing rotors under three different types of protective supports are studied by numerical simulation. At present, there are quite mature methods to study the "fall-rub" behavior in fixed ring and ball bearing, and the numerical simulation results have been proved by experimental research, As for the new MLDSB provided in this paper, it is studied by adding a static pressure system to the electromagnetic bearing. Both the electromagnetic bearing system and the hydrostatic pressure system are mature technologies. They can ensure that the simulation results accurately describe the real operating conditions.The author believes that the numerical method can reveal the difference between the MLDSB and the traditional AMB.
To the suggestion 3: The electromagnetic bearing system under three kinds of protection supporting form "fall - rub" dynamic behavior characteristics are shown in Figure 9 to 15, which adopted the axis trajectory, electromagnetic force, the input current and rubbing force to describe these processes, in this paper I take partial enlarged and display the data graph and the corresponding text to comparison and quantitative description.
To the suggestion 4: In Table 2, the magnitude of rubbing force and the specific duration of impact are written in order to achieve a more intuitive effect, which can be divided into two tables of upper unit failure and bilateral failure.
To the suggestion 5: As for suggestions are written in the appended file,We have made careful modifications. See the attachment for more details.
We deeply appreciate your consideration of our manuscript, and we look forward to receiving comments form the reviewers. If you have any queries please don't hesitate to contact me.
Thank you and best regards.
Yours sincerely,
Lanchun Xing,Sheng Li.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This manuscript presents the dynamic behavior analysis of magnetic liquid double suspension bearing under three protective devices. Overall, the manuscript is well written and can be considered for publication in Processes. However, the contribution is not self-evident in its current presentation. The authors have mentioned a few existing works in the introduction, it is unclear what issues have been addressed in this work. It is recommended that the authors rework the introduction and clarify the novelty in this work.
The authors may also comments on how the research findings in this work can be used for the research community, e.g., is it helpful to identify and fix electromagnetic failure.
Author Response
Dear Reviewer:
I am very glad to receive your review report. In view of your suggestion, I put forward the following solution.I hope these changes can meet your expectations.
We add "However, the protection mechanism of the rotor/ stator by the static pressure system in this new bearing system is not clear yet, and the difference between the static pressure system and the traditional protection bearing needs to be explored." in introduction to describe the meaning and innovation of manuscript. Please see the attachment for more details.
We deeply appreciate your consideration of our manuscript, and we look forward to receiving comments form the reviewers. If you have any queries please don't hesitate to contact me.
Thank you and best regards.
Yours sincerely,
Lanchun Xing,Sheng Li.
Author Response File: Author Response.docx
Reviewer 3 Report
I would propose several major improvements to this manuscript.
1) Abstract should overview obtained results.
2) The abstract is lack paper claims.
3) The contribution and motivation of the paper need to be clearly stated.
4) Section 2.1 is limited to the linear model of the impact-rubbing?, the assumptions should be given.
5) Sections 2.1. 2.2, need references to these models.
6) Section 3, software and simulation details are missing, how relevant are these results? And how we can trust them?
7) How is possible to make an experimental verification?
8) Some sentences in the paper text are too long and not consistent.
9) The literature coverage of this paper needs to be expanded to deal with also AMB and magnetorheological fluids:
a) The robust control of magnetic bearings for rotating machinery. By: Gosiewski, Zdzislaw; Mystkowski, Arkadiusz. Conference: 1st International Conference on Mechatronic Systems and Materials Location: Vilnius, LITHUANIA Date: OCT 20-23, 2006. Sponsor(s): Vilnius Gediminas Tech Univ; Kaunas Univ Technol; UNESCO Int Ctr Engn Educ; Lithuanian Acad Sci; IFToMM Natl Comm Lithuania. MECHATRONIC SYSTEMS AND MATERIALS Book Series: Solid State Phenomena Volume: 113 Pages: 125-130
b) The sedimentation of magneto-rheological fluid monitoring system based on resistivity measuring. By: Vezys, J.; Dragasius, E.; Volkovas, V.; et al. MECHANIKA Issue: 5 Pages: 449-452
10) The conclusions should be supported with results.
I invite the Authors to respond to the reviewer comments and revise their paper.
Author Response
Dear editor:
I am very glad to hear about you. I have made corresponding modifications to your suggestions and hope you can adopt them.
To the suggestion 1, 3, 5, 8 and 10, I have revised the manuscript accordingly, please check out.
To the suggestion 2: I'm not very clear about what's the paper claims, I hope you can give me more specific example about it.
To the suggestion 4: The assumptions is not just limited to the linear model of the impact-rubbing, it's be used in a momentary impact situation. For details, please refer to corresponding references 1, 16 and 17. Their model contains nonlinear parts.
To the suggestion 6: The software uses Matlab. The initial conditions of the simulation parameters have been given in this paper, and all the descriptions are based on the simulation facts.
To the suggestion 7: The test rig is still in the commissioning stage. We plan to install different protection devices to study the dynamics of the rotor.
To the suggestion 9: I have added reference A to the paper (Shown in reference 15). However, there is no magnetorheological fluids in our MLDSB system. Therefore, I think it is inappropriate to add reference B.
sincerely,
Lanchun Xing.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
Dear Authors,
thank you for your improvements, please make a revision of the references, and improve some mistakes, i.e. reference no 15, "Zdzislaw" and "Arkadiusz" are names, not surnames.
Author Response
Dear editor:
I'm very glad to hear about you. I've given some modifications to the references. Please check out.
Sincerely,
Lachun Xing.
Author Response File: Author Response.docx
