An Improved Version of ETS-Regression Models in Calculating the Fixed Offshore Platform Responses

Round 1

Reviewer 1 Report

1. abstract: “As the hydrodynamic drag-dominated force was always a challenge, the hydrodynamic drag-dominated force was always a challenge” Please check the sentence and manuscript carefully.

2. line 72 of page 2: “This section may be divided by subheadings. It should provide a concise and precise description of the experimental results, their interpretation, as well as the experimental conclusions that can be drawn.” What is the meaning of the sentence in the manuscript?

3. line 77 of page 2: “Specifications of the physical structure were fixed structures, quasi-static responses with a drag coefficient (Cd) and inertia coefficient (Cm) equal to 1.05 and 1.20, respectively.” What is the basis for selecting values of 1.05 and 1.2?

4. line 79 of page 2: “A jacket structural model admitted in this study was at an ocean depth of 110 m in the North Sea”, I can't understand the sentence.

5. Is the fixed platform comprised of a four-legged platform in Figure 1 a jacket structural model in the North Sea? And what are the suggestions to meet the high sea state conditions without wave-induced current effects? What is the limit of ocean depth?

6. page 7: There are two 3.1 sections and is a problem with typesetting.

7. line 139 of page 4: Is it necessary to describe water Particle Kinematics and Linear Random Wave Theory when Morison’s Equation has been given?

8. Poor quality of figures 4(b), 5(a) and 6.

9. Conclusions should focus on the primary research findings.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

For more consistency in the structural assessment, the linearised drag-inertia force was considered in model development, such as an improved version of the Efficient Time Simulation Regression (ETS-Reg) procedure was introduced. In order to evaluate the level of accuracy, the recent ETS-Reg models were compared and validated using the Monte Carlo time simulation (MCTS) method. An amended ETS-Reg model, known as the ETS-RegLR compared with the previous results obtained using the conventional ETS-Reg models (ETS-RegSE leading to better structural responses calculations.  Before publication, the following comments should be considered and answered to improve the quality of the work.

1. The value of research needs to be highlighted.

2.How much has the efficiency of proposed method improved?

3.More detailed calculation parameters shall be provided.

4.The English quality of the manuscript should be improved more.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The reliability of any offshore structure is dependent upon the applied environmental loads and its structural resistance, the latter required to support the former. In seeking to assess this balance, the primary source of uncertainty lies in the loading. The time-domain analysis has been commonly preferred to assess offshore structures because it provides considerable benefits to the practicing engineer without losing accuracy. However, such assessments are high computational demands and time costs due to complex numerical procedures in completing the loadings on the offshore structures. In the presented study, the authors try to get closer to solving the problem outlined above.

The article is relevant and deserves to be published after minimal edits. Below are comments on the text of the article.

1. The authors do not appear to follow a standard structure for a research paper. Let me remind you that the Research manuscript should include sections: Introduction, Materials and Methods, Results, Discussion, Conclusions.

2. The introduction for a research article must be completed with a clear indication of the problem that has not been solved to date and a clear statement of the purpose of the research.

3. I would like to see a clear answer to such a question in the review part of the article. What is the conceptual difference between the presented article and a previously published study: Syed Ahmad, Sayyid Zainal Abidin and etc. (2019). Offshore responses using an efficient time simulation regression procedure. https://doi.org/10.1201/9780429298875-2

If this is a development of previously proposed approaches or their refinement, then more precise information should be given about it.

4. Analyzing the presented graphical results, it can obviously be concluded that the ETS ETS-Reg_SE model provides a lower level of accuracy than the ETS-Reg_LR model (if both models are compared with the reference calculation procedure). Moreover, in some areas this difference in results approaches 20%, but there are areas where the difference does not exceed 4%. What is the reason for such results? Is it possible to identify areas in which the models give similar results?

5. The conclusion should include the future research direction and the shortcomings of this study. 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx