Structural Integrity Assessments of an IMO Type C LCO2 Cargo Tank
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe overall structure of the paper is complete and logical, and the limit state, fatigue life and buckling assessment of IMO Type C LCOâ‚‚ cargo tank has been systematically analysed with engineering reference value. However, there are still several improvements that can be made in terms of methodological details and technical depth.
- only a single design temperature of -35°C is given in the paper, without discussing the effect of -50°C or even lower temperatures on the material toughness or fracture toughness that may occur in LCOâ‚‚ during different filling rates or pressure relief processes.
- does the buckling calibration take into account internal pressure effects?
- detailed weld modelling of solids (weld toe radius, weld throat thickness) is not given in the text.
- on what criteria is the correspondence between loading cycles and actual conditions based?
- note the consistency of the terminology in the article, e.g. "hydraulic pressure test" or "hydrostatic pressure test".
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript “Structural integrity assessments of an IMO type C LCO2 cargo tank” addresses an actual problem related to engineering analysis of a particular design of a liquefied carbon dioxide tank. For doing so, the structural integrity of an IMO Type C cargo tank for a medium-range LCOâ‚‚ carrier was estimated under four conditions: i) ultimate limit state, ii) accidental limit state, iii) hydraulic pressure test, and iv) fatigue limit state. The engineering requirement for the assessment followed the IGC code and classification rules. The calculations were carried out with the use of FEM software for seventeen load cases. Multistep loading was employed to ensure the stability. It has been shown that the highest stress occurred at the pump dome–shell junction due to geometric discontinuities. Fatigue calculation simulating wave-induced loads have established negligible risk of fatigue damaging, while low-cycle fatigue from loading/unloading operations could occur after 31,000 years of service. The conducted calculations have shown proven the tank’s structural robustness, ensuring suitability for safe, efficient medium-pressure LCOâ‚‚ transportation.
The topic of the manuscript falls within the scope of the journal of Marine Science and Engineering.
The state of the art is rather roughly analyzed regardless, the number of cited references is equal to 28.
The design criteria exactly follow industrial IGC code.
Data on numerical analysis are duly described.
The results of numerical analysis are clearly described as well.
The conclusions are not very informative, since numerical values are missing.
The level of English language is OK.
The manuscript might be accepted for the publication in the journal of Marine Science and Engineering; however, it requires a major revision.
The key drawback is its engineering formulation. Everything was done according to the requirements of IGC code. But it is a research paper. What was the hypothesis? What was the problem? What are the key scientific findings? The service life of 31,000 years is a superior result, but it is rather far from a reality. Probably an optimization problem was to be solved?
In addition, the following aspects are to be addressed by the authors.
Page 1, line 14. IMO abbreviation is given without description of full name.
Page 1, line 16. ICG abbreviation is given without description of full name.
Page 1, line 23. ULS, ALS, FLS, HPT abbreviations are given without description of full name.
Page 6, line 175. “at locations where crack detection is difficult, such as internal structures”. What does the latter mean?
Page 14, line 379. “Analysis results”. It should rather be: “Analysis of results”.
Page 17, line 454. “the maximum stress ratio occurred under the ULS load case.” The exact value of stress is to be specified, since it is a conclusion of the technical paper.
Page 17, lines 455-457. “In particular, the highest stress was observed at the junction between the pump dome and the cylindrical shell, which was attributed to stress concentration caused by geometric discontinuities.” The exact value of stress is to be specified, since it is a conclusion of the technical paper.
Page 17, lines 463. “a significantly high stress ratio was observed”. The exact value of stress is to be specified, since it is a conclusion of the technical paper.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsMost of the reviewer's comments and concerns were due addressed. The manuscript might be accepted for the publication in the revised form.
