Precomputation of Critical State Soil Plastic Models

Round 1

Reviewer 1 Report

Article: Precomputation of Critical State soil plastic models

General comments:

            In the context of geotechnical simulation, the engineering community usually suffers from the costly and time-consuming numerical simulation, especially for large scale analysis. In this paper, the authors are intended to present a smart solution in which the current stress states can be normalised. The clear benefit of the method is its ability to reduce the computation time without destroying the precision.

            Certainly, the reviewer could recommend the publication for the present work. However, still several comments are listed below to improve the comprehensibility.

Title:

Line 1: According to the reviewer, the title should be as follow:

Precomputation of Critical State Soil Plastic Models

Abstract:

Line 12: The sentence is a little strange for the reviewer. Whether it might be revised as follow:

“………when the boundary value problems appear at the yield surface with the calculation of plastic strain………”

Line 14: The reviewer believes that a scalar number might be more persuasive and convincing in the Abstract to demonstrate the performance of the proposed method. Please modify the sentence as follow:

“………significant reduction of about 50% (as compared with the conventional explicit integration algorithm) in the computational time………”

1. Introduction:

Line 24: The reviewer understands very well the definition of active clays, but the reviewer do not believe that the potential readers of this journal could always have a solid geotechnical background. Please briefly explain this material.

Line 41-46: In general, the conventional method to solve boundary value problems is sub-stepping technologies such as Euler forward/backward method with error controlled algorithm. The authors may want to briefly introduce the related literatures. And then, we could better understand the motivation of the authors’ to develop this novel normalisation method to overcome the numerical problem.

2. Theoretical background:

Line 56-59: The equation (1) is OK for the reviewer, but I do not understand why the presented methodology could be very necessary if an elastic model of deformation is adopted (such as the argument between Line 60-61). Whether it might be better to provide a conceptual figure of NCL and unloading-reloading line to emphasize this argument?

Line 70-71: Whether the sentence should be revised as follow:

“………although they are associated with different hardening parameters ………”

Line 77: For equation (5), the engineering and Voigt notations are employed together to simplify the multiplication. So, change the ‘or’ to be ‘and’.

Equation (5): Whether de should be in bold format ?

Equation (6)-(7)-(8)-(10) and (18): In the PDF version that the reviewer examined, there are certainly some display problems of these equations, the authors should carefully fix them.

Equation (8): The authors may want to explain why the D^p matrix is not symmetric.

Line 90: Please revise “po” to be “p_o”.

3. Evaluation of the precomputation efficiency:

Line 123-124: Whether there is a unit for the computational cost tabulated in Table 1 ?

Figure 3 (a): The reviewer understands well, the P, Q in Figure 3a should be replaced by p, q.

3.Precomputation density:

Figure 7: The x-ticks labels in the figure are not well displayed as the authors desired. Please correct it.

The last two sections are Ok for the reviewer.

Author Response

24 November 2021

Ref.:   Revised manuscript

Manuscript ID: processes-1480409

Title: Precomputation of Critical State soil plastic models

Dear Referee

We have revised the manuscript in accordance with your comments. The changes are marked with "Track Changes" in the new version of the manuscript. It is attached as a PDF. In the same document, after a cover letter, we detail how we have addressed all your comments. We are grateful for your work and his creative attitude. We hope that with the changes introduced the manuscript can be accepted for publication.

I look forward to hearing from you.

Sincerely,

Prof. Vicente Navarro

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper shows a procedure to find the yield point using an elastoplastic model. This methodology was made through optimization and avoiding additional calculations. However, the application of this procedure does not prove to be a valuable advance in the profession because there is no real application example. For example, a practical finite element problem. I think this should be corrected before publication. In the current state, it is uninteresting to the reader. Additionally, the following points should be addressed:

- Page 1, lines 30-13, the phrase “where the computational time can determine the viability of the study” the references are Old, which should be explained. This explanation should be given because, in recent years, a significant number of advances in computing power and optimization have been created.

- Page 2, lines 55-59, Butterfield's law is not the original MCC model. So, I do not understand why you mention it if you are using the normal law of the MCC model. Furthermore, Equation 1 is the original MCC model (see Desai Equation 11-5b). Would you please explain this clearly?

- Constitutive laws for engineering materials: With emphasis on geologic materials, by C. S. Desai and H. J. Siriwardane, Prentice-Hall, Inc., Englewood Cliffs, New Jersey 07632, 1984, ISBN 0-13-167940-6.

- Page 2, lines 73-78, why does the procedure not use an unassociated flow rule? This rule better represents the experimental results. Could you please explain this?

- There are some grammatical/ semantics errors throughout this paper (e.g., Pages 3, 5, and so on). Would you mind doing a general reading and correcting these errors?

- Page 7, lines 167-169, the text is unclear, and I don't understand what you want to present in Figure 6. Would you please explain this clearly?

- Please make a list of symbols.

- Page 9, line 210, what is Equation 23?

- In the conclusion, why is the process not implemented in a UMAT (or user material) to be used in a FEM model where the saving of time is shown?

Author Response

24 November 2021

Ref.:   Revised manuscript

Manuscript ID: processes-1480409

Title: Precomputation of Critical State soil plastic models

Dear Referee

We have revised the manuscript in accordance with your comments. The changes are marked with "Track Changes" in the new version of the manuscript. It is attached as a PDF. In the same document, after a cover letter, we detail how we have addressed all your comments. We are grateful for your work and his creative attitude. We hope that with the changes introduced the manuscript can be accepted for publication.

I look forward to hearing from you.

Sincerely,

Prof. Vicente Navarro

Author Response File: Author Response.pdf