Fatigue Life Analysis of the Submarine Rudder Stock Mechanism at Arctic Low Temperatures

Round 1

Reviewer 1 Report

Interesting topic and approaches. However, the story of the paper is confusing. Arctic is acclaimed, but only low temperature effects are considered and some kind of combined loading. However, in the arctic we can expect to have ice, which potentially interacts with the rudder. This is however not considered, but what I expected when reading the first pages of the paper. The conclusions are now to general and not backed-up with the date of the paper.

 

“This method can provide a reference for ship design and life model establishment in the Arctic environment.” >> the paper deals with the example of a submarine, thus it is not obvious to utilise this for ships in general. Rephrase or prove!

 

Figure 11. Why are these tests not all starting at (0,0) - this is very surprising and makes me wonder how this information was now utilised further? What is the link between Figure 14 and 15 - much more explanations on the methods and procedure are needed here also. I do not understand how the low temperature effect is accounted for in the fatigue analysis? The reference should be “Braun et al.” not “Moritz et al.”

This statement “When the temperature is 0 °C, 20 °C, and 40 °C, there is no significant difference in the fatigue life of the rudder stock mechanism.” Is only true for the material tested, yet again, I am not sure how the materials behaviour obtained was linked to the analysis.

Author Response

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Reviewer 2 Report

This is in general interesting study on important topic of submarine rudder at sub-zero temperatures.  The paper is quite well written and easy to read. However, there is a drawback as the commercial software is used without proper discussion on the background physics. In particular, I have following comments: 

1. Q in Equation 1 should be defined.

2. It is really not clear why authors performed tensile tests of specimens and what is the relationship with the fatigue calculation procedure. I think that for fatigue life calculation,  fatigue experiments should be performed. 

3. Boundary conditions and the loading of FE model (Fig 12) should be specified

4. The type of stresses presented in Fig.13 should be clarified.

Author Response

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Round 2

Reviewer 1 Report

Thank you for addressing my comments nicely. I can accept your answers and have no further comments.

Author Response

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Reviewer 2 Report

Please account following comments before publishing:

1. The title of Figure 12 should be FE mesh

2. Figure 13 is unclear. BC and loads should be magnified

3.  4.2.3.  LEFM is abbrev. for linear elastic fracture mechanics not for fatigue crack propagation (FCP)

4.Figure 15 -  R-ratio life curves is unusual title for S-N curve and should be corrected

 

Author Response

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