Simulation Analysis of Organic–Inorganic Interface Failure of Scallop under Ultra-High Pressure

Round 1

Reviewer 1 Report

Coatings
Manuscript ID: coatings-1748740
Title: Analysis of the mechanical properties for organic-inorganic material interface failure of scallops under the ultra-high pressure
Authors: Xue Gong, Jiang Chang, Yinglei Zhang, ZhiHui Sun, Ning Xia, Huajiang Zhang, Jing Wang, Xiang Zhang

In this paper, the authors have analyzed stress distribution at the interface of the shell and muscles of a scallop. The geometry was idealized for analysis and using many assumptions, the change in stress distribution due to the change in geometry of the shell and other features have been studied using finite element analysis. The reviewer has the following comments.

Following are the comments.

1.    The title is not appropriate. There is no data regarding mechanical property of the shell or its muscle, which is presented in this paper. The focus is rather stress analysis and hence, the title should be modified accordingly.
2.    The abstract does not reflect the content of the paper. The abstract should be shortened and it should be modified by correctly specifying the objectives and outcomes of this research.
3.    No mathematical expression or equations should be written in the abstract. Remove mathematical expressions from line 17 and 18.
4.    End of Section-1, line 71 and 72. The authors write:
“The study of the interface failure mechanism of scallop muscle and shell can effectively explain the shelled mechanism of scallop under ultra-high pressure”.
Though ‘failure mechanism’ is written in title, abstract and at many places, no failure criteria is presented in the paper. Are the authors using any stress-based or fracture mechanics based failure criteria? Please elaborate and write the details in the ‘Introduction’ section.
5.    Equations (1) to (11) and (13) are known to all the readers and these are available in any standard textbook. Hence, these equations should be removed. Only the governing differential equation (i.e., 2), boundary conditions and final solution should be written. In fact, the whole section (2) should be one paragraph only as it is very standard.
6.    Table-1: How are the Young’s modulus and Poisson’s ratio evaluated? How are the experiments conducted on shell and muscle? What kind of specimen are used in the experiment and what is the rate of loading? These are important and the authors should explain these details along with presentation of relevant data on force-displacement and stress-strain curves.
7.    Fig. 2 and other finite element analysis results: What are the boundary conditions? How does this model simulate the actual scallop geometry? What kind of material properties are used in analysis? Is geometric and material nonlinearity considered in analysis of deformation of muscle? It may be noted that muscle is like a nonlinear elastic material and hence, appropriate constitutive models are essential to simulate the deformation behavior. These details needs to be discussed and addressed suitably.
8.    Fig. 6(a): Provide geometrical details (i.e., radius of curvature, dimensions) of the model, boundary and loading conditions. The results should be addressed from this perspective.
9.    The effect of interface cracks and defects should be included in the FE analysis. Otherwise, discussion on interface failure mechanism is incomplete. Moreover, suitable failure criteria needs to be incorporated and discussions should be modified accordingly.
10.    Conclusions: This section should be re-written. Only important conclusions should be highlighted.
11.    There are many grammatical mistakes and at many instances, sentence construction is itself inappropriate. Please check the whole manuscript and modify appropriately.
12.    In the reference section, papers on nonlinear material models appropriate for shells and muscles of scallop should be included and these should be reviewed in Section-1.
13.    There should be some discussion on directional-dependence property and deformation behavior of shell and muscle of scallop. The authors use isotropic models in their analysis. The applicability of their assumption to actual condition should be discussed.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors,

Thank you for submitting your paper to Coatings. In the paper, a simulation of organic tissue subjected to high pressure is presented. The model itself is very simplified and thus hardly reliable. You treat the tissue in the same way as a regular anisotropic material, for example, steel, which does not seem proper.  I wonder what is section 2.2.2 for. The equations you present are well-known formulas including those for the axisymmetric case. The same is valid for constitutive equations for linear-elastic material. The numerical model is poorly described. You only presented the elastic properties of a muscle and a shell. And you did not provide information about the system that you used for calculations nor details of the mesh including analyses of mesh sensibility and boundary conditions. Depending on boundary conditions it is probably not needed to model the whole shell but only a small piece neighboring the muscle.

During reading, I found some editorial problems.

Line 24: "In the study" or "The study analyzed"

Line 25: the long sentence should be divided into two starting from "The mechanical model..."

Lines 35-36: Sentence should be rephrased

Line 57: ", and"

Fig.1. missed designations "c" and "d"; red arrows are missed in Fig. d.

Line 109: wrong figure number

Line 153: "equation"

Line 154: "constitutive"

Line 171: "r"

Line 252-254: The sentence is slightly entangled for me. I would change "stress distribution clouds" into just "stress field"

Line 274" "Is the "fourth strength theory" which is suitable for plastic materials. Why do you apply it to elastic materials?

Line 301: "angle"

Line 372: "scientific value"

Line 399: only "pressure", "force" is not necessary

Figures are blurred especially if one wants to read the scale.

Best regards,

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have revised the manuscript considering the comments of the reviewers. However, there are many assumptions regarding the geometry, presence of cracks at the interface, material model etc. as used in finite element analysis, which is not relevant to the problem (e.g., material of the muscle of the scallop is nonlinear elastic, whereas it is assumed as elastic in the analysis). This aspect must be written clearly in the discussion of the results section of the manuscript. The limitations of the approach and their effect on the results must be discussed.

Author Response

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Reviewer 2 Report

Dear Authors,

The improved version of the article looks much better. In fact, there is one editorial problem: Fig. 6 is cut and the lower part, including the figure caption, is not visible.

Best regards,

Author Response

Please see the attachment

Author Response File: Author Response.docx