Preform Porosity and Final Thickness Variability Prediction after Controlled Post-Infusion External Pressure Application with the FEA Model
Round 1
Reviewer 1 Report
Title: Preform porosity and final thickness variability prediction after controlled post-infusion external pressure application with the FEA model
Authors: Igor Zhilyaev and colleagues
Overall assessment:
In this manuscript, there are various relations many readers cannot understand precisely immediately after reading because of the wrong arrangements. Additionally, it is often difficult whether these relations are obtained from the equations or FE calculations. Even if the method demonstrated in this study is novel, the equations are often complicated; therefore, I have a concern that these equations can be used in practical operations. I recommend the authors to rewrite the manuscript from the beginning and resubmit the new version.
Followings are the specific comments on the manuscript which may be helpful for the resubmission:
Specific comments:
1. Terminology: Both the “module” and “modulus” are mixed up. These presentations are correct, aren’t they? Or they can be expressed uniformly using either of them?
2. Perhaps <nu>zx in Eq. (9) is the Poisson’s ratio in the zx plane, but the definition is missing.
3. “Poisson ratio” in Table 1 should be denoted as “Poisson’s ratio”.
4. The presentations of the properties listed in Table 1 must be more elaborated. For example, “E-11” should be represented as “10-11”.
5. It is difficult to understand which “K0” is defined for the x, y, z axes or for the xy, yz, and zx planes.
6. The readers must be confused that K0 is the property different from those of Ks and Kf. I strongly recommend the authors to use a different character.
7. The details of the FEM program used for the analyses must be demonstrated.
8. It seems to me that the finite element mesh is too coarse to obtain an accurate solution. The authors must demonstrate the validity of the solutions obtained using the finite element mesh.
9. It is inconvenient to compare the results obtained from the FEAs and experimental data, which are published in several previous papers [13-15, 25, 26]. Due to the inconveniency, it is often difficult to evaluate whether the method demonstrated in this paper is valid or not. I strongly recommend the authors to demonstrate several comparisons in this paper.
Author Response
Dear reviewer! All your comments have been taken into account, the answers to them are contained in the attached letter, and the corresponding changes have been made to the text of the revised article on a yellow background for ease of verification.
Sincereli, authors
Author Response File: 
Author Response.doc
Reviewer 2 Report
This manuscript is focused on the finite element modeling of infusion stage of manufacturing polymer based composites. Generally, most of the results make sense to me. However, there are some mistakes in the present form that need to be addressed. Detailed comments are shown below.
1. Abstract. The background takes up more than 50% of the abstract, and details of this work are described with very few sentences. Therefore, I suggest the authors to re-organize the abstract.
2. Mistakes. There are some language mistakes that need to be addressed. There are also some other mistakes, such as table caption of Table 1 (‘Table 1. This is a table. Tables should be placed in the main text near to the first time they are cited.’) and superscript mistakes in Table 1 and Fig. 7.
3. The FE model was used in this work. I’m wondering how the authors selected the parameters of the simulation, such as length, width, and thicknesses of the system in Fig. 2 (Page 6), pinl=100 kPa and pout=20 kPa (Page 6-7), Δt =10 min (Page 8), et al.
4. From Fig. 4b, it is seen that the absolute value of mass flux of outlet is higher than that of inlet, after the flow is stabilized (Not equal as the authors claimed in Page 6). Any explanation?
5. Fig. 8. Please add the unit for the pressure.
6. The lower pictures of Fig. 9. The value of upper limit is 0.42, which is the same to that of super limit. It will be better to change the number of decimal places for the porosity data. Fig 10 has similar issues.
Author Response
Dear reviewer! All your comments have been taken into account, the answers to them are contained in the attached letter, and the corresponding changes have been made to the text of the revised article on a green background for ease of verification.
Sincereli, authors
Author Response File: Author Response.doc
Reviewer 3 Report
This article is a comprehensive numerical study of the variations of important process variables in vacuum infusion process. In particular, the article focuses on the effects of the application of an external pressure during post infusion and how pressure affects the porosity and thickness uniformity of the composite part. The article is well-written and properly organized. The authors do a good job in explaining their motivation and why such a numerical study based on FEA modeling is important. I recommend the publication of this article.
While this is an important study, I also recommend that the authors articulate the possibility of how the application of pressure during infusion might be manipulated to improve the quality of the composite as well as how such an extension may be included in the numerical model. Furthermore, would it be possible to control the pressure to reduce cycle times and achieve a higher production rate if a fast-curing resin is used?
Author Response
Dear reviewer! Your comments have been taken into account, the answer to them is contained in the attached letter, and the corresponding changes have been made to the text of the revised article on a blue background for ease of verification.
Sincereli, authors
Author Response File: Author Response.doc
Round 2
Reviewer 1 Report
The revisions are adequately conducted, so I can recommend the publication of the revised version as it is.
Reviewer 2 Report
The manuscript has been improved after the revision.
Reviewer 3 Report
The authors addressed my comments properly.
