Next Article in Journal
Storage Reliability Assessment Method for Aerospace Electromagnetic Relay Based on Belief Reliability Theory
Previous Article in Journal
An Optimization Method for Personnel Statistics Based on YOLOv4 + DPAC
 
 
Article
Peer-Review Record

New Analytical Free Vibration Solutions of Thin Plates Using the Fourier Series Method

Appl. Sci. 2022, 12(17), 8631; https://doi.org/10.3390/app12178631
by Bing Leng 1,2, Salamat Ullah 3, Tianlai Yu 1,* and Kexin Li 2
Reviewer 2:
Reviewer 3:
Appl. Sci. 2022, 12(17), 8631; https://doi.org/10.3390/app12178631
Submission received: 30 July 2022 / Revised: 18 August 2022 / Accepted: 24 August 2022 / Published: 29 August 2022

Round 1

Reviewer 1 Report

The paper should be improved according to the following:


1) In the introduction it should be mentioned clearly what is new in the paper relative to the previous work of the same Authors.
2) Grammatical, spelling, and syntactic check is required for the manuscript. Some minor mistakes have been detected.

3) The comprehensive frequency parameter should be explained better.
4) The “Discussion” and “Conclusions” parts of the manuscript should be more detailed and analyzed.
5)
The process of equation solving, should be more detailed. How the boundary conditions are applied?
6) There is only a comparison with the Finite element Method. A comparison of the results should be made with another analytical or experimental investigation in order to improve the quality of the paper.

7) In the finite element analysis there is no information about the type of elements used, the mesh, and the convergence for the results.

8) In the results section there is nothing about Figures 2-5. An interpretation of the results should be given.
9) Emphasis should be given, in the results section, on the benefits of the obtained results with reference to engineering applications.

Author Response

Reviewer: 1

Before the Editor makes a decision, I suggest that the authors must take into account the following corrections:

Our response: We thank the reviewer for this accurate summary of our work and the important comments detailed below.

  1. The title should be rewritten to be friendly.

Our response: We thank the reviewer for the important comment. According to the suggestion, we have rewritten the title of the present paper. The new title is presented here for easy reading of the reviewer. “New analytical free vibration solutions of thin plates using the Fourier series method”.

  1. The author should explain the novelty clearly in the abstract and conclusion.

Our response: We thank the reviewer for the insightful comment. To better explain the novelty of the paper, abstract section and conclusion section have been modified and added in a revised manuscript highlighted in yellow. The revised ones are also presented here:

Abstract: This article aims at analytically solving free vibration problem of rectangular thin plates with one corner free and its opposite two adjacent edges rotationally-restrained, which is difficult to handle by conventional semi-inverse approaches such as the Levy solution and Naiver solution, etc. Based on the classical Fourier series theory, this work presents a first endeavor to treat the two-dimensional half-sinusoidal Fourier series, which is quite similar to the Navier’s form solution, as the solution form of plate deflection. Via utilizing the orthogonality of the present trial function and the Stoke’s transformation technique, the present solution procedure converts the complicated plate problem into solving sets of linear algebra equations, which heavily decreases the difficulties. Therefore, the present approach enables one to solve the title problem in a unified, simple and straightforward way, which is very easily implemented by researchers. Another advantage of the present method over other analytical approaches is that it has general applicability to various boundary conditions through utilizing different types of Fourier series and it can be extended for further dynamic/static analysis of plates under different shear deformation theories. Moreover, without any extra derivation process, new precise analytical free vibration solutions for plates under three non-Levy-type boundary conditions are also obtained by choosing different rotating fixed coefficients. Consequently, we present more than 400 comprehensive free vibration results for plates with classical/non-classical boundaries, all the present results are confirmed by FEM/analytical solutions and can be used as benchmark data for further research.

Conclusion

A new two-dimensional improved Fourier series approach is developed to seek exact analytical free vibration solution of thin plates under classical/non-classical edge conditions. The significant merits of the present method differing from other analytical methods are: (1) it provides a more simple and straightforward solution procedure for precise plate free vibration analysis since it avoids some complicated mathematical manipulations such as the transformation procedure in finite integral transform method or superposition procedure in symplectic superposition approach; (2) within the framework of Fourier series theory, it reduces the mathematical difficulty of plate problem by converting the boundary value problems of higher-order partial differential equation into solving linear algebra equations; (3) it provides more precise analytical solutions for mechanical problems of moderately-thick/thick plates under more complicated boundary conditions via using different types of Fourier series. The present trial function exactly satisfies both the governing vibration formula and the non-classical boundaries after determining the unknown constants with obvious physics meaning. In addition, new analytical solutions for the CCFF, CSFF and SSFF plates are also acquired by choosing rotating fixed coefficients introduced. Consequently, we provided new exact results, including 50 mode shapes and more than 400 natural frequencies, for intractable title problem. In the present parametric analysis, it is found that both the aspect ratio and boundary restraint significantly influence the free vibration behaviors of plates. All the analytical results are precise enough since they agree well with the results obtained via using the FEM and other analytical methods, which are promising to validate solutions of other methods.

  1. The paper should be carefully revised for punctuation, grammar, spelling mistakes and sentences structuring. For example, in abstract:

 “it’s opposite” should be “its opposite”

 “such as Levy solution” should be “such as the Levy solution”

 “form of plates deflection” should be “form of plate deflection”

 “to solve title “ should be “to solve the title”

 “different type Fourier series” should be “different types of Fourier series”

 “under different shear deformation theory” should be “under different shear deformation theories”

Our response: We would like to thank the reviewer for careful and thorough reading of this manuscript and for the thoughtful comments and constructive suggestions, which help to improve the quality of this manuscript. According to the suggestion, we have carefully revised the paper and made modifications, for example:

Abstract: This article aims at analytically solving free vibration problem of rectangular thin plates with one corner free and its opposite two adjacent edges rotationally-restrained, which is difficult to handle by conventional semi-inverse approaches such as the Levy solution and Naiver solution, etc. Based on the classical Fourier series theory, this work presents a first endeavor to treat the two-dimensional half-sinusoidal Fourier series, which is quite similar to the Navier’s form solution, as the solution form of plate deflection. Via utilizing the orthogonality of the present trial function and the Stoke’s transformation technique, the present solution procedure converts the complicated plate problem into solving sets of linear algebra equations, which heavily decreases the difficulties. Therefore, the present approach enables one to solve the title problem in a unified, simple and straightforward way, which is very easily implemented by researchers. Another advantage of the present method over other analytical approaches is that it has general applicability to various boundary conditions through utilizing different types of Fourier series and it can be extended for further dynamic/static analysis of plates under different shear deformation theories. Moreover, without any extra derivation process, new precise analytical free vibration solutions for plates under three non-Levy-type boundary conditions are also obtained by choosing different rotating fixed coefficients. Consequently, we present more than 400 comprehensive free vibration results for plates with classical/non-classical boundaries, all the present results are confirmed by FEM/analytical solutions and can be used as benchmark data for further research.

 

All the other modifications are highlighted in yellow, please check the revised manuscript.

  1. In the introduction, all authors should be given by family name only for example: “D. J. Gorman” must be “Gorman” …….

Our response: We thank the reviewer for the important comment. We have modified our manuscript according to the reviewer comments, please check the revised manuscript.

  1. In the article, all refs. should be given by family name and distance then number for example: “Yilong Wang[1]” must be “Wang [1]” …….

Our response: We appreciate the reviewer for the important comment. We fully agree with the reviewer, and modify all references in introduction part according to the reviewer’s suggestion. Please check the revised manuscript.

  1. Why, the equations (8), (9) and (10) have 4 equations? Should be give more explanations

Our response: We appreciate the reviewer for the important comment. Why equations (8), (9) and (10) have 4 equations is for the following reasons:(1) formulas for the fourth order derivatives of the deflection (such asand ) are used to substituted into Eq. (3) to obtain Fourier coefficient ; (2) expressions for ,, and are used to derive relationships of some unknown constants, such as ; (3)expressions for are used to satisfy the bending moment requirements along the rotationally-restrained edges, and expressions for the , are used to compose bending moments and then satisfy the bending moment requirements along the free edges.

  1. The literature survey must be improved on adding some relevant references as: Analytical solution for a free vibration of a thermoelastic hollow sphere. Mech. Based Des. Struct. Mach. 2015, 43, 265-276, doi:10.1080/15397734.2014.956244.

Wave propagation in a generalized thermoelastic plate using eigenvalue approach. Journal of Thermal Stresses 2016, 39, 1367-1377, doi:10.1080/01495739.2016.1218229.

Vibrational behavior of thermoelastic rotating nanobeams with variable thermal properties based on memory-dependent derivative of heat conduction model. Arch Appl Mech 2022, doi:10.1007/s00419-022-02110-8.

Our response: We thank the reviewer for the important comment. All the references suggested by the reviewer are added in the text and reference section and highlighted in yellow in revised manuscript. The added sentences and references are also addressed here:

“Based on a nonlocal elasticity theory and the generalized heat conduction model with phase delays, Ahmed [17] provides Sinusoidal form solutions for the thermomechanical problem of rotating size-dependent nanobeams with clamped–clamped boundary conditions. ………… Based on the generalized thermoelasticity theory, Abbas [22] obtains the analytical solution for the temperature, displacement components, and stresses of thermoelastic material plates by utilizing an eigenvalue approach. Via using the same method, the author [23] also provides new accurate analytical solutions for the free vibration problem of thermoelastic hollow sphere, in which the dispersion relations for various types of possible vibration modes of the hollow sphere are well derived.”

 

  1. Abouelregal AE, Atta D, Sedighi HM. Vibrational behavior of thermoelastic rotating nanobeams with variable thermal properties based on memory-dependent derivative of heat conduction model. Archive of Applied Mechanics 2022:1–24.
  2. Abbas, Ibrahim A, Abdalla, Abo-El-Nour N, Alzahrani, Faris S, et al. Wave propagation in a generalized thermoelastic plate using eigenvalue approach. Journal of Thermal Stresses 2016;39:1367–77.
  3. Abbas, Ibrahim, A. Analytical Solution for a Free Vibration of a Thermoelastic Hollow Sphere. Mechanics Based Design of Structures & Machines 2015;43:265–76.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Before the Editor makes a decision, I suggest that the authors must take into account the following corrections:

1.      The title should be rewritten to be friendly.

2.         The author should explain the novelty clearly in the abstract and conclusion.

3.        The paper should be carefully revised for punctuation, grammar, spelling mistakes and sentences structuring. For example in abstract:

-          “it’s opposite” should be “its opposite”

-          “such as Levy solution” should be “such as the Levy solution”

-          “form of plates deflection” should be “form of plate deflection”

-          “to solve title “ should be “to solve the title” 

-          “different type Fourier series” should be “different types of Fourier series”

-          “under different shear deformation theoryshould be under different shear deformation theories”

   4.          In the introduction, all authors should be given by family name only for example: “D. J. Gorman” must be “Gorman” …….

 

-   5.         In the article, all refs. should be given by family name and distance then number for example: “Yilong Wang[1]” must be “Wang [1]” …….

 

-    6.         Why, the equations (8), (9) and (10) have 4 equations? Should be give more explanations

   7.    The literature survey must be improved on adding some relevant references as:

-Analytical solution for a free vibration of a thermoelastic hollow sphere. Mech. Based Des. Struct. Mach. 2015, 43, 265-276, doi:10.1080/15397734.2014.956244.

-  Wave propagation in a generalized thermoelastic plate using eigenvalue approach. Journal of Thermal Stresses 2016, 39, 1367-1377, doi:10.1080/01495739.2016.1218229.

- Vibrational behavior of thermoelastic rotating nanobeams with variable thermal properties based on memory-dependent derivative of heat conduction model. Arch Appl Mech 2022, doi:10.1007/s00419-022-02110-8.

 

    

 

 

 

 

 

 

Author Response

Response to Reviewer’s 2 Comments

Reviewer: 2

This manuscript presents an analytical solution for free vibration of rectangular thin plates under classical/non-classical edge conditions. The following concerns, however, must be addressed:

Our response: We thank the reviewer for this accurate summary of our work and the important comments detailed below.

  1. A careful reading of the text should be done to suppress language errors.

Our response: We greatly appreciate the reviewer’s careful reading. The language of the manuscript is improved and highlighted in yellow in the revised manuscript. Please refer to the revised manuscript.

  1. In “1. Introduction”, the application background is lacking. This may leave the readers confused about the significance of the study.

Our response: We thank the reviewer for the important comment. According to the reviewer’s suggestion, we have made some modifications of introduction part to point out the significance of the study. The modifications are also presented here for easy reading of the reviewer.

“Rectangular thin plate is considered as the basic structural element in practical applications because of its relevance in various engineering fields such as civil and structural engineering, mechanical engineering, naval and aerospace, etc. The extensive application of such structures needs to investigate the dynamic characteristics of thin plates to establish an accurate and reliable design. It is confirmed that free vibration of plate causes reduction in structure stiffness which reduces its load carrying capacity, as a result may cause premature structure failure. Simultaneously, a clear understanding of natural frequencies and associated mode shapes is the basis for reliable design toward avoiding plate’s resonance problem. However, it is difficult to deal with free vibration problem of plates under various boundary conditions, especially for the ones with complex non-classical boundaries.”

  1. The authors have performed a series of numerical simulations. Please detail the establishment of the numerical models. It is not appropriate to show only the results without describing the model establishment.

Our response: We thank the reviewer for pointing this out. We have added the following sentence in Comprehensive frequency parameter and mode shape results section to provide the information for finite element modeling. It is also presented here for easy reading of the reviewer.

“It is worth noting that the reliable FEM results for comparison are acquired by using ABAQUS 6.13 (2013), where 4-node thin shell element S4R is employed. To guarantee the accuracy of the FEM results, we testify the convergence for the FEM results of CCFF plate with aspect ratio b/a=1 as is shown in Table 1. It is found that most of the obtained FEM results for converge when the mesh size is 1/400 of the plate length. Thus, the uniform mesh size with short edge length of 1/400 is adopted throughout the present study.”

Table 1 Convergence of the dimensionless frequency parameter obtained by FEM for the CCFF square plates with different mesh sizes.

 

Mode

first

second

third

fourth

fifth

sixth

seventh

eighth

ninth

tenth

1/100

6.9190

23.905

26.590

47.654

62.711

65.572

85.726

88.377

121.50

124.21

1/200

6.9187

23.901

26.585

47.646

62.711

65.539

85.694

88.341

121.38

124.08

1/300

6.9185

23.900

26.584

47.642

62.705

65.532

85.686

88.332

121.35

124.06

1/400

6.9184

23.900

26.583

47.640

62.702

65.529

85.682

88.328

121.34

124.05

1/500

6.9183

23.900

26.583

47.639

62.702

65.529

85.682

88.327

121.34

124.05

 

  1. The color legend is lacking in Figs. 2–5. Without color legend, the color changes in these figures are meaningless. Please add.

Our response: We thank the reviewer for the important comment. Actually, the present study provided mode shape figures for the non-dimensional frequency parameter of CCFF, CSFF, and SSFF square plates. To eliminate the confusion of the reviewer, we presented new mode shape figures without color, which were modified in the revise manuscript. The modification is also shown below for easy reading of the reviewer. We greatly appreciate the understanding of the reviewer.

 

 

Mode shapes

first

second

third

fourth

fifth

Present

         

FEM

         

 

sixth

seventh

eighth

ninth

tenth

Present

         

FEM

         

Fig. 2 First ten mode shapes of the square CCFF plate with ,  

 

 

 

Mode shapes

first

second

third

fourth

fifth

Present

         

FEM

         

 

sixth

seventh

eighth

ninth

tenth

Present

         

FEM

         

Fig. 3 First ten mode shapes of the square CSFF thin plate with ,  

 

 

Mode shapes

first

second

third

fourth

fifth

Present

         

FEM

         

 

sixth

seventh

eighth

ninth

tenth

Present

         

FEM

         

Fig. 4 First ten mode shapes of the square SSFF plates with ,  

 

 

Mode shapes

first

second

third

fourth

fifth

           
           
           
           

Fig. 5 First five mode shapes of the RRFF square plates with,  and equaling 0.1, 0.3, 0.5 and 0.8.

 

  1. In Page 9, it is mentioned that “…in Tables 1-3, it is clearly found that the acquired of CCFF plates is larger than that of CSFF and SSFF plates; values of for CSFF plates are larger than values of for SSFF plates, which reveals…” There are no relevant results for SSFF plates in Tables 1–3. Please check.

Our response: We thank the reviewer for pointing this out. Actually, we have made a spelling mistake, results in Table 4 are for SSFF plates. We have modified the title of Table 4. The title modified is also presented here for easy reading of the reviewer.

Table 4 Frequency parameter  of SSFF rectangular plates with defined rotational fixity factors  and aspect ratio  changing from 0.5 to 5

 

Author Response File: Author Response.pdf

Reviewer 3 Report

This manuscript presents an analytical solution for free vibration of rectangular thin plates under classical/non-classical edge conditions. The following concerns, however, must be addressed:

1. A careful reading of the text should be done to suppress language errors.

2. In “1. Introduction”, the application background is lacking. This may leave the readers confused about the significance of the study.

3. The authors have performed a series of numerical simulations. Please detail the establishment of the numerical models. It is not appropriate to show only the results without describing the model establishment.

4. The color legend is lacking in Figs. 2–5. Without color legend, the color changes in these figures are meaningless. Please add.

 

5. In Page 9, it is mentioned that “…in Tables 1-3, it is clearly found that the acquired of CCFF plates is larger than that of CSFF and SSFF plates; values of for CSFF plates are larger than values of for SSFF plates, which reveals…” There are no relevant results for SSFF plates in Tables 1–3. Please check.

Author Response

Response to Reviewer’s 3 Comments

Reviewer: 3

The paper should be improved according to the following:

Our response: We thank the reviewer for this accurate summary of our work and the important comments detailed below.

1 In the introduction it should be mentioned clearly what is new in the paper relative to the previous work of the same Authors.

Our response: We thank the reviewer for the important comment. We have added and modified some sentences of the introduction part to illustrate the main novelties of the present study. The modifications are highlighted in yellow in the revised manuscript and also are presented here for easy reading of the reviewer.

“Considerable literatures confirm that the Navier’s form solutions are still accurate analytical solutions of the ideal form because of their simplicity and excellent orthogonality. It is well acknowledgement that Navier’s solution is the most commonly used in analyzing static and dynamic problems of plates since its simple solution procedure. However, Navier’s solution is only suitable for plates with all edges simply-supported. Consequently, it is of great significance to extent such effective classical approach to solve problem of plates under more complex boundaries. Motivated by the above situation, a two-dimensional improved Fourier series approach is developed to provide exact vibration analysis of plates under the complicated non-classical boundary restraints. For the first time, we treat the two-dimensional half-sinusoidal Fourier series as the trial function for the deflection of plates. Interestingly, the adopted trial function is quite similar to the Navier’s form solution and automatically satisfies the zero deflection at rotationally restrained edges, zero effective shear force at free edges and zero twisting moment at the free corner. We also make a first endeavor to introduce the Stoke’s transformation technique on deriving detailed expressions for the first four order derivatives of the deflection, in which some associated unknown constants with obvious physical meaning can also be acquired. The obtained constants can be solved by dealing with sets of linear simultaneous equations after putting the obtained derivatives of the deflection into the remain boundaries. The present solution procedure and new Fourier series expansions, which can be directly adopted for solving mechanical problems of thick plates, are the main contribution of the present study. Another advantage of the present study is that new precise free vibration results for rectangular thin plates under classical boundaries can be obtained via selecting different coefficients of the rotational springs introduced. Therefore, four different types of boundaries including RRFF, CCFF, CSFF and SSFF are considered for the investigated plate, where the free, rotationally-restrained, simply supported and clamped edge are respectively designated as F, R, S and C. The present work chooses a clockwise representation for the boundaries studied, starting from the edges of x=0. Finally, we list new precise results for the dimensionless natural frequency parameters and plot the corresponding mode shapes, all of which are testified to be qualified as new exact benchmarks after comparing with the ones solved by the conventional finite element method and other analytical methods.”

2 Grammatical, spelling, and syntactic check is required for the manuscript. Some minor mistakes have been detected.

Our response: We greatly appreciate the reviewer’s careful reading. Grammatical, spelling, and syntactic of the paper have been carefully checked. We revised our manuscript according to the reviewer comments and highlighted revision in yellow. Please refer to the revised manuscript.

3 The comprehensive frequency parameter should be explained better.

Our response: We thank the reviewer for the important comment and suggestion. We have made modifications in “Comprehensive frequency parameter and mode shape results” part of the revised mauscript and highlighted revision in yellow. The modifications are also presented here for easy reading of the reviewer.

 

“As is shown in Table 2-4, the non-dimensional frequency parameter decreases as the aspect ratio  increases and vice versa. Therefore, the minimum values of  corresponds to the aspect ratio (5.0). The non-dimensional frequency parameter decreases rapidly when the aspect ratio is 1 or less than one. Additionally, it can be observed that the values of  changes very few when  changes from 2.5 to 5. It can be concluded that the aspect ratio from 0.5 to 2.0 has more influence on the natural frequencies as compared to the aspect ratio from 2.5 to 5. Through Tables 2-4, it also found that boundary conditions have great influence on the non-dimensional frequency parameter. The acquired   for all boundary conditions is higher as the aspect ratio gets smaller than one. The magnitude of  is always greater for CCFF than those under CSFF and SSFF when aspect ratio  is same. Also, the non-dimensional frequency parameter for CSFF is higher than the SSFF for all aspect ratio. It can be concluded that the plate with more clamped edges requires more energy to vibrate. Through comparisons in Tables 2-4, it is clearly seen that all the results obtained are in good agreement with ones solved numerically or analytically, especially with those in Ref[43]. Similarly, through Tables 5-6, it is obvious the obtained   increases with the increase of rotating fixed coefficient r, which indicates that the RRFF plate with stricter boundary constraints needs more energy to vibrate. The aforesaid parametric analysis indicates that both the aspect ratios and the degree of boundary restraint effect free vibration behaviors of plates significantly.”

4 The “Discussion” and “Conclusions” parts of the manuscript should be more detailed and analyzed.

Our response: We thank the reviewer for the important comment and suggestion. According to the suggestion, we have modified some sentences to give more detailed frequency parameter analysis. We did not present it here since it was already shown in our response to Comment 3. We then added some sentences to better explain the mode shape results of the present study. The sentences added are also present below for easy reading of the reviewer. We finally made modifications for the conclusion section according to the suggestion of the reviewer. The revised conclusion is also presented here:

As is shown in Figures 2-4, it is easily found that all the obtained free vibration mod shapes for the CCFF, CSFF and SSFF plates match well with the ones provided by the Finite element method. It is also obviously found the present mode shapes strictly satisfy the boundary conditions, which confirm the accuracy of the present method. Through Figure 5, it is found that the mode shapes for the RRFF plate under different degree boundary restraints change gradually, which further confirm the affections of boundary conditions on the free vibration characteristics of plates.

Conclusion

A new two-dimensional improved Fourier series approach is developed to seek exact analytical free vibration solution of thin plates under classical/non-classical edge conditions. The significant merits of the present method differing from other analytical methods are: (1) it provides a more simple and straightforward solution procedure for precise plate free vibration analysis since it avoids some complicated mathematical manipulations such as the transformation procedure in finite integral transform method or superposition procedure in symplectic superposition approach; (2) within the framework of Fourier series theory, it reduces the mathematical difficulty of plate problem by converting the boundary value problems of higher-order partial differential equation into solving linear algebra equations; (3) it provides more precise analytical solutions for mechanical problems of moderately-thick/thick plates under more complicated boundary conditions via using different types of Fourier series. The present trial function exactly satisfies both the governing vibration formula and the non-classical boundaries after determining the unknown constants with obvious physics meaning. In addition, new analytical solutions for the CCFF, CSFF and SSFF plates are also acquired by choosing rotating fixed coefficients introduced. Consequently, we provided new exact results, including 50 mode shapes and more than 400 natural frequencies, for intractable title problem. In the present parametric analysis, it is found that both the aspect ratio and boundary restraint significantly influence the free vibration behaviors of plates. All the analytical results are precise enough since they agree well with the results obtained via using the FEM and other analytical methods, which are promising to validate solutions of other methods.

5 The process of equation solving, should be more detailed. How the boundary conditions are applied?

Our response: We appreciate the reviewer for the important comment. Actually, the given Eq. (16) in this article has been simplified already. In order to eliminate the confusion on how to apply the boundary condition, we have added and modified some equations. The modifications for the equations and the associated sentences are presented here for easy reading of the reviewer.

Expressions for the RRFF plate, in which rotationally-restrained at edges  and , and its opposite corner free, are described as:

                                  (4)

 

Substituting the assumed  and its fourth high-order derivatives appeared in Eqs. (8)–(10) into Eq.(3) yields the following expression for the free vibration governing equation :

         (12)

It is obvious that is zero since the zero twisting moment at free corner. Similarly, due to the zero deflection at rotationally-restrained edges (, ) and  effective shear force at free edges (, ), it is easy to derive that

                                                                                                                      (13)

                                                                                                                (14)

                                                                                        (15)

It is clearly that  are the Fourier coefficients of the slope along the free edges. Obviously,  and  are the Fourier coefficients of bending moments along the rotationally-restrained edges, the corresponding bending moments can be directly acquired by the following formula:

                          (16)

One can obtain the following simplified expression for the free vibration governing equations by substituting Eqs. (13)-(15) into the Eq. (12), which is shown below:

                                               (17)

After obtain the expression for , using the solution procedure expressed by     Eqs. (20)-(28) to determine the unknown constants , ,  and , then one can obtain analytical solutions satisfy both the governing vibration equation and the boundaries investigated.

All the other modifications are highlighted in yellow, please check the revised manuscript. We greatly appreciate the understanding of the reviewer.

 

6 There is only a comparison with the Finite element Method. A comparison of the results should be made with another analytical or experimental investigation in order to improve the quality of the paper.

Our response: We appreciate the reviewer for the important comment. We agree that it is necessary to compare the present results with those obtained by other analytical methods or experimental investigation. We thus made further literature review, and found some comparable results obtained by other analytical methods. Unfortunately, we did not find suitable experimental results. We greatly appreciate the understanding of the reviewer. The comprehensive comparison has been incorporated in Tables 1-3 which are shown below. The reference added and corresponding sentence modified are highlighted in yellow in revised manuscript and presented here for easy reading of the reviewer.

“Consequently, we present more than 400 comprehensive free vibration results for plates with classical/non-classical boundaries, all the present results are confirmed by FEM/analytical solutions and can be used as benchmark data for further research.”

 

“Aim at testifying the capability of the proposed approach in predicting free vibration response for rectangular thin plates with classic/non-classic type edge conditions, new precise comprehensive results including frequency parameters and the associated mode shapes are in comparison with FEM results and the existing analytical solutions[16,43].”

“Through the comparisons in Tables 2-4, it is clearly seen that all the results obtained are in good agreement with ones solved numerically or analytically, especially with those in Ref[43].”

“Excellent agreement is found between the present numerical/graphical results with FEM solutions and other analytical solutions, which confirms the qualification of the present method in solving complex plate problems.”

 

“All the analytical results are precise enough since they agree well with the results obtained via using the FEM and other analytical methods, which are promising to validate solutions of other methods.”

 [16]     Li WL, Zhang X, Du J, Liu Z. An exact series solution for the transverse vibration of rectangular plates with general elastic boundary supports. Journal of Sound and Vibration 2009;321:254–69.

[43]      Zhang J, Lu J, Ullah S, Gao Y, Zhao D, Jamal A, et al. Free vibration analysis of thin rectangular plates with two adjacent edges rotationally-restrained and the others free using finite Fourier integral transform method. Structural Engineering and Mechanics 2021;80:455–62.

 

 

Table 2 Frequency parameterof CCFF rectangular plates with defined rotational fixity factors  and aspect ratiochanging from 0.5 to 5.

 

 

Mode

first

second

third

fourth

fifth

sixth

seventh

eighth

ninth

tenth

0.5

Present

17.118

36.372

73.402

90.902

115.20

131.62

158.98

208.74

219.42

248.45

Ref[43]

17.118

36.372

73.402

90.902

115.20

FEM

17.116

36.363

73.391

90.894

115.17

131.60

158.93

208.73

219.36

248.46

1

Present

6.9191

23.903

26.587

47.651

62.706

65.531

85.697

88.342

121.35

124.05

Ref[43]

6.9191

23.903

26.587

47.651

62.706

FEM

6.9184

23.900

26.583

47.640

62.702

65.529

85.682

88.328

121.34

124.05

1.5

Present

4.9677

13.235

23.278

30.112

34.138

52.236

56.033

62.667

72.788

78.511

FEM

4.9673

13.233

23.275

30.110

34.132

52.227

56.029

62.666

72.781

78.498

2

Present

4.2795

9.0929

18.351

22.726

28.800

32.904

39.745

52.184

54.855

62.112

Ref[43]

4.2795

9.0929

18.351

22.726

28.800

FEM

4.2793

9.0918

18.349

22.724

28.795

32.901

39.738

52.181

54.846

62.111

2.5

Present

3.9726

7.1296

13.038

21.728

22.798

26.402

33.479

34.675

43.607

50.053

FEM

3.9725

7.1287

13.037

21.726

22.796

26.399

33.474

34.675

43.600

50.049

3

Present

3.8149

6.0344

10.143

16.364

22.227

24.570

25.416

30.169

35.642

37.386

FEM

3.8148

6.0338

10.142

16.362

22.225

24.567

25.414

30.164

35.641

37.380

3.5

Present

3.7249

5.3602

8.3946

12.940

19.077

22.202

24.211

26.928

28.171

33.423

FEM

3.7248

5.3598

8.3937

12.939

19.076

22.200

24.208

26.925

28.167

33.417

4

Present

3.6692

4.9175

7.2540

10.721

15.406

21.228

22.251

23.714

26.642

28.644

FEM

3.6692

4.9171

7.2533

10.720

15.405

21.226

22.249

23.712

26.639

28.642

4.5

Present

3.6327

4.6127

6.4673

9.2024

12.885

17.543

22.045

23.047

23.585

25.704

FEM

3.6328

4.6125

6.4668

9.2015

12.884

17.541

22.043

23.046

23.585

25.701

5

Present

3.6075

4.3952

5.9014

8.1166

11.086

14.844

19.383

22.081

23.066

24.665

FEM

3.6075

4.3949

5.9009

8.1158

11.085

14.843

19.382

22.080

23.064

24.663

Table 3 Frequency parameterof CSFF rectangular plates with defined rotational fixity factorsand aspect ratio  changing from 0.5 to 5.

 

 

Mode

first

second

third

fourth

fifth

sixth

seventh

eighth

ninth

tenth

0.5

Present

8.5061

30.954

64.140

70.962

92.922

128.79

139.47

199.83

202.51

208.60

Ref[43]

8.5062

30.955

64.142

70.962

92.927

FEM

8.5030

30.943

64.137

70.950

92.899

128.79

139.45

199.81

202.50

208.59

1

Present

5.3508

19.073

24.673

43.087

52.706

63.754

77.488

83.660

106.29

120.34

Ref[43]

5.3509

19.075

24.671

43.087

52.707

FEM

5.3499

19.071

24.675

43.076

52.706

63.754

77.476

83.652

106.28

120.33

1.5

Present

4.4122

10.870

22.852

25.572

32.347

48.278

49.368

62.439

71.359

72.932

FEM

4.4117

10.869

22.850

25.570

32.340

48.270

49.364

62.437

71.351

72.920

2

Present

4.0292

7.8658

15.849

22.573

27.800

29.251

37.927

47.071

51.891

61.980

Ref[43]

4.0294

7.8661

15.850

22.576

27.801

FEM

4.0290

7.8649

15.847

22.572

27.798

29.250

37.924

47.071

51.887

61.979

2.5

Present

3.8434

6.4013

11.522

19.657

22.430

25.953

31.191

32.724

41.880

46.016

FEM

3.8433

6.4005

11.520

19.656

22.428

25.949

31.189

32.718

41.872

46.015

3

Present

3.7409

5.5654

9.1527

14.784

21.990

22.884

24.843

29.525

32.902

36.284

FEM

3.7409

5.5650

9.1523

14.785

21.990

22.883

24.841

29.523

32.901

36.281

3.5

Present

3.6792

5.0420

7.7087

11.830

17.544

22.149

23.969

25.093

27.675

32.667

FEM

3.6791

5.0416

7.7079

11.829

17.543

22.147

23.966

25.092

27.671

32.662

4

Present

3.6393

4.6931

6.7580

9.9093

14.261

19.828

22.154

23.584

26.245

26.958

FEM

3.6392

4.6928

6.7574

9.9084

14.260

19.826

22.152

23.583

26.242

26.956

4.5

Present

3.6121

4.4497

6.0968

8.5895

12.010

16.405

21.614

22.259

23.298

25.486

FEM

3.6121

4.4494

6.0962

8.5887

12.009

16.404

21.613

22.257

23.297

25.483

5

Present

3.5927

4.2735

5.6176

7.6419

10.402

13.945

18.278

22.041

22.938

23.570

FEM

3.5928

4.2733

5.6171

7.6412

10.401

13.944

18.278

22.040

22.936

23.569

 

Table 4 Frequency parameter  of SSFF rectangular plates with defined rotational fixity factors  and aspect ratio  changing from 0.5 to 5

 

 

Mode

first

second

third

fourth

fifth

sixth

seventh

eighth

ninth

tenth

0.5

Present

6.6436

25.374

58.740

65.177

89.093

113.14

131.50

185.64

189.60

202.12

Ref[16]

6.644

25.370

58.739

65.183

89.084

113.17

Ref[43]

6.6437

25.375

58.741

65.179

89.096

FEM

6.6401

25.366

58.729

65.175

89.065

113.13

131.47

185.63

189.55

202.13

1

Present

3.3668

17.314

19.292

38.208

51.034

53.485

72.964

74.626

104.71

107.22

Ref[16]

3.370

17.321

19.293

38.203

51.032

53.497

Ref[43]

3.3670

17.316

19.293

38.210

51.035

FEM

3.3659

17.313

19.292

38.199

51.033

53.485

72.945

74.614

104.71

107.21

1.5

Present

2.2328

9.5393

16.679

24.543

26.993

44.058

48.175

51.149

61.061

68.835

FEM

2.2321

9.5374

16.678

24.540

26.987

44.047

48.173

51.148

61.052

68.821

2

Present

1.6607

6.3435

14.684

16.293

22.273

28.291

32.875

46.416

47.401

50.531

Ref[43]

1.6609

6.3438

14.685

16.295

22.274

FEM

1.6605

6.3427

14.682

16.292

22.271

28.291

32.870

46.415

47.395

50.530

2.5

Present

1.3195

4.7306

10.316

15.789

18.845

20.100

27.184

30.659

37.051

45.407

FEM

1.3192

4.7296

10.314

15.789

18.843

20.097

27.179

30.658

37.043

45.406

3

Present

1.0937

3.7679

7.8075

13.722

15.734

18.629

21.949

23.967

31.060

32.321

FEM

1.0935

3.7674

7.8068

13.720

15.734

18.627

21.947

23.966

31.058

32.320

3.5

Present

0.93401

3.1304

6.2428

10. 680

15.513

16.705

17.882

21.828

24.305

27.372

FEM

0.93375

3.1297

6.2418

10. 679

15.512

16.704

17.880

21.825

24.303

27.367

4

Present

0.81491

2.6776

5.1872

8.6529

13.220

15.555

17.240

19.093

20.477

24.784

FEM

0.81468

2.6770

5.1863

8.6518

13.219

15.555

17.239

19.092

20.475

24.780

4.5

Present

0.72280

2.3397

4.4321

7.2357

10.892

15.228

15.742

16.910

19.424

21.101

FEM

0.72260

2.3391

4.4314

7.2346

10.891

15.227

15.742

16.909

19.422

21.100

5

Present

0.64944

2.0779

3.8673

6.2000

9.1985

12.915

15.471

16.562

17.498

18.740

FEM

0.64926

2.0775

3.8667

6.1990

9.1975

12.914

15.471

16.562

17.497

18.738

 

7 In the finite element analysis there is no information about the type of elements used, the mesh, and the convergence for the results.

Our response: We thank the reviewer for pointing this out. We have added the following sentence in Comprehensive frequency parameter and mode shape results section to provide the information for finite element modeling. It is also presented here for easy reading of the reviewer.

“It is worth noting that the reliable FEM results for comparison are acquired by using ABAQUS 6.13 (2013), where 4-node thin shell element S4R is employed. To guarantee the accuracy of the FEM results, we testify the convergence for the FEM results of CCFF plate with aspect ratio b/a=1 as is shown in Table 1. It is found that most of the obtained FEM results for converge when the mesh size is 1/400 of the plate length. Thus, the uniform mesh size with short edge length of 1/400 is adopted throughout the present study.”

Table 1 Convergence of the dimensionless frequency parameter obtained by FEM for the CCFF square plates with different mesh sizes.

 

Mode

first

second

third

fourth

fifth

sixth

seventh

eighth

ninth

tenth

1/100

6.9190

23.905

26.590

47.654

62.711

65.572

85.726

88.377

121.50

124.21

1/200

6.9187

23.901

26.585

47.646

62.711

65.539

85.694

88.341

121.38

124.08

1/300

6.9185

23.900

26.584

47.642

62.705

65.532

85.686

88.332

121.35

124.06

1/400

6.9184

23.900

26.583

47.640

62.702

65.529

85.682

88.328

121.34

124.05

1/500

6.9183

23.900

26.583

47.639

62.702

65.529

85.682

88.327

121.34

124.05

 

8 In the results section there is nothing about Figures 2-5. An interpretation of the results should be given.

Our response: We appreciate the reviewer for the important comment. We have added some sentences to give the interpretation of the obtained mode shape results. We did not present them here since they were already shown in our response to Comment 3. Please check the response to Comment 3.

 

9 Emphasis should be given, in the results section, on the benefits of the obtained results with reference to engineering applications.

Our response: We thank the reviewer for the important comment. According to the suggestion of the reviewer, we have added some sentences into “Comprehensive frequency parameter and mode shape results” part and highlighted them in yellow. The sentences added are also presented here for easy reading of the reviewer.

Obviously, all the present the non-dimensional natural frequency parameters and the associated vibration mode shapes can be adopted for engineers and scientists for academic and practical applications.The laws indicated by the present parametric analysis enable designers to effectively avoid resonance problems of rectangular thin plate structures.

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

accept

Reviewer 3 Report

This manuscript was revised according to the comments, which could meet the requirement of acceptance.

Back to TopTop