Mechanical Analysis of DS in Horizontal Directional Drilling

Round 1

Reviewer 1 Report

• Overall very good presentation of the research
• A more detailed explanation of the FEM model would be valuable
• Could have shown the assumptions, hypothesis, and limitations of the proposed model
• Field data validation of the experiment results should be considered

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The experimental analyses carried out in this work is deepened and the conclusions asserted are supported by the results. Conversely, I was not able to identify the novelties introduced with this work. Such topic was widely discussed in literature and numerous models and simulations were proposed. For that reason, in this first round, I ask to the authors to clearly highlights the scientific novelties they introduced with this manuscript. 

Moreover, there are some minor comments.

The article must be inserted in the correct format.

The abstract must be revised: the first sentence is referred to a specific project ("HDD project with a lenght of 5200 meters"); however, by its own, the abstract cannot help to identify it. There are two possibilities: add some information more or avoid to mention it. 

Moreover, it should be rewritten; I know that it is a keyword, but the term "drill string" is used 17 times in the abstract.

There are several grammar and typos errors in the text (i.e. it continue instead of it continues; iss and so on).

If mentioned in the text, the references should be put in alphabetical order.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

This study on the mechanical analysis of drillstring in horizontal directional drilling is interesting research with valuable findings. following comments can improve this manuscript:

It is better to condense the abstract and explained it with fewer sentences. 

Define acronyms before use for the first time in the manuscript : (WOB), sliding mode control (SMC). Also, I suggest not using dashes for SMC to be consistent.

A discussion part is required to be added with the application section in order to compare results with expectations based on previous studies and what is introduced in the literature.

use millimeters equivalents for drillstrings in parenthesis when you mentioned in the text for the first time

add units for figure 8. also you can have the numbers in decimals instead of scientific format. 

mention your ideal boundary and compare it with real case conditions and discuss the changes in the reliability of the results somewhere in the discussion.

 

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors followed my suggestions and revised the paper correctly. I propose to consider the present article for publication.