Micro-Scale Numerical Simulation for Residual Strength of CFRP After Cyclic Tensile or Out-of-Plane Shear Loadings Fatigue
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper focused on micro-scale numerical simulations to evaluate the residual strength of CFRP subjected to cyclic transverse and out-of-plane shear loading fatigue. And some experiments were conducted to determine the non-linear coefficient of stress-strain curve. However, the test conditions are complex. Is it reasonable to select only 220 MPa as the material property in Table 1?
Comments on the Quality of English LanguageThe quality of the writing needs to be improved. Many grammatical errors throughout the manuscript need to be corrected.
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Reviewer 2 Report
Comments and Suggestions for AuthorsThe work is devoted to the development of a criterion for assessing fatigue loads in carbon fiber reinforced plastics; the parameter 𝛼𝑜(𝑠) is proposed to describe the accumulation of entropy of the system under loads. The results of numerical modeling describe the mechanical behavior of the material using the Maxwell model. The text of the manuscript is well structured.There are a number of critical comments
1. line 25-28. "....with few studies employing numerical methods to investigate the strength degradation behavior of CFRPs deeply " I disagree with the phrase about the paucity of numerical studies of carbon fiber reinforced plastics. The authors cite 18 references for the last 2-3 years, but numerical modeling of carbon fiber fracture has been conducted for at least the last 40 years. It is necessary to describe the shortcomings of previously used models and provide arguments for the introduction of a new model or a new criterion that will be considered in this article.
2. Before the theoretical justification and numerical calculations, it is better to describe in 2-3 sentences what needs to be found or determined in this work to obtain the final results.
For example. For numerical modeling of the residual resource of carbon fiber and determination of the criterion describing the change in the entropy of the system under loads, it is necessary to describe the boundary conditions of the finite element model using the Maxwell model and the Hashin's criteria. and so on.
3. I cannot understand why the authors present the results of creep and their dependence on temperature, although these results were not used in the numerical calculation and determination of the parameter 𝛼𝑜(𝑠).
In my opinion, section 3 should be removed.
4. Section 2. Hashin's Criteria. These criteria were described in previous works of prof. Koyanagi. What are the differences? It is probably best to introduce one or three equations for 𝛼𝑜(𝑠) that will be used in this work.
5. Some equations are not defined in the text. For example Eq (21)-(24).
6. Please improve the description of numerical calculation results. What is damage coefficient? What about the location of the maximum damage coefficient values (epoxy or fiber)? How will the localization (epoxy or fiber) of the pinned element affect the results?
Author Response
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Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors performed a micro-scale numerical simulation to investigate the residual strength of a CFRP under cyclic transverse and out-of-plane shear loads using an entropy-based damage concept for the matrix. The paper is suitable for publication in JCS. It is suggested that the authors introduce Equations (1) to (15) immediately after the first sentence in Section 2. The second sentence thus would read like "where Eq. 1 to 4 represent ... ". Also, the authors may want to use 'residual strength reduction' instead of simply 'strength reduction' when first introducing the concept in Section 2.
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Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe article still lacks some innovation.
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Reviewer 2 Report
Comments and Suggestions for AuthorsImprovements to the text have been done. The manuscript will be recommended for publication.
Author Response
N/A
