Buckling Strength Assessment of Composite Patch Repair Used for the Rehabilitation of Corroded Marine Plates
Round 1
Reviewer 1 Report
Very correctly written paper. It represents a significant contribution in the field of application of composite materials on steel ship structures, ie mainly on merchant ships. This is especially interesting due to the increasing development of new materials and technologies in the design and construction of structural elements of the hull of merchant ships, and not just small vessels. This opens the way for the application of composite materials in the construction and structural elements of the hull of a merchant ship. As leading classification societies develop procedures for approving new / composite materials/procedures for use in large shipbuilding, a brief overview of the procedure and criteria for the use of composite patches is also worthwhile.
As stated in the conclusion, this is, or should be only the first part, ie the development of the methodology, theoretical basis and numerical calculation, while an experiment must follow, the data of which would enable the validation of the presented methodology and calibration of numerical models.
The title of the paper is appropriately selected, although look like a little bit too long. Summary is clear. Introduction is sufficiently detailed. Maybe it was possible to list EU projects and additional papers resulting from these projects concerning composite patches and joints of composites with steel. Figures and tables are suitable size and resolution and well described. The used units are correct. Calls to figures, tables and references are clear.
The work is well structured, with well-chosen names of chapters. Results and discussion are elaborated in detail and are very promising.
The language and style of writing are very correct. I have no objections.
Only few clarifications have to be done:
Page 4, before or within Table 1 it would be worthy to note the type of matrix used and laminating technology (hand layup, vacuum bagging, infusion) to have better insight on yield/fracture stress. Also, it would be nice to have data on adhesive material used (type and basic mechanical properties).
Page 8, Equation (3), D to be explained (plate stiffens?).
Page 9, Equation (7), so to be explained
Page 14, Figure 13 a) and b), suppose that SS stands for single strap, and DS for double strap?
Author Response
Response to Reviewer 1 Comments
Point 1: As leading classification societies develop procedures for approving new / composite materials/procedures for use in large shipbuilding, a brief overview of the procedure and criteria for the use of composite patches is also worthwhile.
Response 1: Thank you for your note. The procedure and criteria for the use of composite patches as proposed by DNV is shown in the flowchart of Figure 5, which is explained in the paragraph beginning in line 170
Point 2: Maybe it was possible to list EU projects and additional papers resulting from these projects concerning composite patches and joints of composites with steel.
Response 2: The authors agree with the reviewer that a reference to EU projects would be valuable. Several EU projects have examined the topic, such as the Marstruct project, the Copatch project and the Ramsses project. A reference to them is added in line 77.
Point 3: Page 4, before or within Table 1 it would be worthy to note the type of matrix used and laminating technology (hand layup, vacuum bagging, infusion) to have better insight on yield/fracture stress. Also, it would be nice to have data on adhesive material used (type and basic mechanical properties).
Response 3: Thank you for your comment. The matrix is epoxy-resin based and the application method is vacuum infusion. A note is added to the Table 1 footer in line 136. Since the study is preliminary and adhesive is out-of-scope, its properties are not referenced in the paper.
Point 4: Equation (3), D to be explained (plate stiffens?).
Response 4: “D” is the plate’s flexural rigidity and its definition is added on line 237.
Point 5: Equation (7), s to be explained
Response 5: The σ0 value is the yield stress σy and has been corrected. Additional explanation for the “y” subscript is also added on line 242.
Point 6: Figure 13 a) and b), suppose that SS stands for single strap, and DS for double strap?
Response 6: Your assumption is correct, and an explanation is added to the caption of the figure (line 400).
Reviewer 2 Report
This study investigated the material wastage and the risks of buckling in a stiffened panel due to corrosion. A repair method of adding composite patches was studied. Finite Element Analysis (FEA) and Design of Experiments (DoE) have been used for the parametric study to obtain an optimal design in terms of composite patch’s percentage coverage and the number of plies. The results proved that the repair method is capable of rehabilitating the buckling capacity of a corroded marine plate against compressive and shear loads. The results and findings are very interesting. There are some questions and concerns that need to be addressed by authors:
- The authors may remove the word “computational mechanics” in Keywords since the study is more of an engineering practicing study instead of theoretical computational theory or method development.
- In line 114, “The most important of them” may be changed into “The important ones” since many items have been mentioned.
- In line 182, the authors mentioned: “a design parameter is examined, while all other factors remain fixed.” Will multi-parameter interaction affect the results of the case studied.
- In line 230, the authors stated that “In the case of shear buckling, the critical elastic stress is calculated using the following equation (3)” Is there any reference that supports the user of the equation? If yes, please add it to the manuscript.
- In section 4.1, what material models (constitutive) did the authors use for metal and composites. Did they consider the yielding of the metal? If not, please explain why.
- In line 307, the author claimed that “However, the same modeling cannot be applied to the shear buckling problem.” Please explain why.
- In Fig. 12, the y axis title was not introduced in the paper, please explain more details.
Author Response
All comments have been addressed successfully. Please check the attachment.
Author Response File: 
Author Response.pdf
