Establishment and Calibration of Discrete Element Model for Buckwheat Seed Based on Static and Dynamic Verification Test

Round 1

Reviewer 1 Report

Remarks

(1) The first thing is the determination of the modulus of elasticity of the seeds. In the DEM the modulus of elasticity E of the material of the particle is used. However, the methodology used in the article to determine the E is averaging of the many factors that take into account many subsidiary things. Due to the non‑regular edged shape of the seeds, the force-displacement dependence of the buckwheat seeds specimen is non-linear with respect to the displacement. The nonlinearity is caused by the contact of the seeds. Therefore the quantity calculated by Eq. (2) is not the modulus of elasticity E of the seed material, but it is just a deformation parameter that is indirectly related to the modulus of elasticity. At least, the authors of the article should use the terms precisely.

(2) Concerning the modulus of elasticity of the seeds again. The authors determined the deformation behaviour index but no discussion is provided on this issue. The thing is that there are at least some articles in which the problem of the determination of the modulus of elasticity is also examined. For example, in “Trotsenko, V. V., Trotsenko, I. V., Komendantova, N. V., and Babariko, A. A., 2021, The Grain Parameters Determination Based on Elements of the Elasticity Theory, IOP Conference Series: Earth and Environmental Science, 659(1), p. 12065” the determination of the modulus of elasticity of the buckwheat seeds were also examined and in addition, according to the article, the determined modulus of elasticity at the same humidity is 20 times bigger than it is determined by the method used in the article under review. That is, 107.62 ± 7.11 MPa against 5.35 MPa. And this ratio is even more illogical since we know that the behaviour of the force‑displacement behaviour of the particles in contact is non‑linear. For example, in the case of the Hert’z law, we have F = k h^(3/2). In addition, there are different methodologies for the determination of the modulus of the elasticity of the grains or seeds.

The authors have not provided any discussion on this issue. Therefore, the authors should provide more discussions on the methodologies of the elastic parameters of the seeds, as well as characterising the deformation parameter of the seeds that the authors mistakenly named as the modulus of elasticity.

In addition, the authors should provide the height of the specimen that is used for the determination of the modulus of elasticity.

(3) In DEM methodology the modulus of elasticity of the material is required. By using this and other quantities the motion of the particles in contact is evaluated by using different contact models. In a normal direction, it could be linear Hook, Hertz etc. In the tangential direction so called Mindlin-Deresiewicz, regularized Coulomb incremental or non-incremental models can be applied. The rolling contact also may involve damping. Not only the normal contact restitution coefficient can be used in the calculations. However, all these details absent in the description of the modelling. The sentence, page 3, lines 100 and 101, “The contact parameters reflect the interaction between particles and particles/walls, and Hertz-Mindlin (no slip) model is widely used in the particle model.” does not tell explicitly what models exactly were used in the modelling. Therefore, the description of the interaction models of the particle‑to‑particle and particle‑to‑wall must be provided in the article more carefully. What realization of the tangential contact was used: incremental or non-incremental? And finally, the formulas of the models for the tangential force-displacement behaviour and for the rolling behaviour also should be given for better understanding.

(4) Figure 9. x-axis is wrongly titled “The static friction coefficient between” between what?

(5) The author also should explain what is PLA plate.

Author Response

The reviewer's professional comments and suggestions are very helpful in improving the author's research and paper writing skills. Thank you very much for the reviewer's work.

The authors have carefully analyzed the review comments and provided a point-by-point response. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

1.The abstract could benefit from an introductory sentence that provides more context about why the study is important.

2.Some of the sentences could be rephrased to improve readability. For example, in the sentence "Under the optimal parameter combination, the dynamic seed metering tests of two particle models are carried out," it would be clearer to say "We conducted dynamic seed metering tests using the two particle models under the optimal parameter combination."

3.It would be helpful to provide more information about the results of the study, such as the specific values of the physical parameters and contact parameters measured in the uniaxial compression test, drop test, and friction coefficient measurement test.

4.The abstract could benefit from a sentence that highlights the practical implications of the study's findings. For example, the authors could mention how the improved accuracy of the seed particle model could be used to design more efficient seed metering devices.

5.Provide some context on why the findings are important or what implications they have for the seed metering device design.

6.Clarify what PLA plates are and how they are relevant to the study.

Author Response

The reviewer's professional comments and suggestions are very helpful in improving the author's research and paper writing skills. Thank you very much for the reviewer's work.

The authors have carefully analyzed the review comments and provided a point-by-point response. Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

All the comments have been well addressed, I have no new comment. 

Author Response

Thank you very much for the reviewer's recognition of the previous response. Your opinion is the best guidance for improving the writing and research abilities of authors.

Thanks again with kind regards.