Influence of Loading Orientation and Knitted Versus Woven Transversal Connections in 3D Textile Reinforced Cement (TRC) Composites
Round 1
Reviewer 1 Report
The paper deals with experimental and numerical investigations on the effects of transversal connections in 3D TRC composites for structural purposes. The topic is innovative and worthy to be investigated since the literature still struggle to depict an exhaustive scenario on this area. The paper is fairly clear; however, a thorough linguistic revision is necessary, possibly by a native English speaker or a professional editing service.
The experimental part is detailed enough, as well as the numerical modelling one. However, the experimental part should be slimmed down, since most experimental results are already published and exposed in detailed in a previous paper by the same group of Authors (Ref. no. [22]).
It is mandatory to fix the hyperlinks to the bibliography items and to the figures/tables. I was quite tough to review the manuscript without correctly connecting the in-text labels with the cited papers and figures.
From the editorial standpoint and for copyright reasons (about which I am not expert and therefore please refer to the editorial office’s opinion), it is strongly advisable not to use the same images of papers, already published with other publishers (consider, for instance, Fig.1, Fig.2 and Fig.6 of this work and Fig.2, Fig.3 and Fig.4, respectively, of [22]).
Even though some of the presented results match with other papers from the same Authors [22, 23], this paper still presents some new information, namely regarding the impact of the loading orientation on the z-directed connections in 3D fabrics. Therefore, to my opinion, the paper is suitable for publication, pending minor revision regarding the remarks listed in the attached file.
Comments for author File: 
Comments.pdf
Author Response
Dear reviewer, the authors would like to thank you for the very valuable comments you provided to the manuscript, they have been seriously taken into consideration in the hope to increase the manuscript’s quality and align closer with the wishes of all reviewers. For this purpose, different changes have been conducted throughout the document. Attached you will find the new manuscript with all changes tracked for ease of understanding. The attached document "Letter to reviewer 1" provides a point-by-point answer to the reviewer's comments.
Author Response File: Author Response.pdf
Reviewer 2 Report
Dear authors! Your article may be worth publishing after radical rearrangement. A short list of the remarks you can see below.
Abstract. TRC - the term should be decripted before use
lines 17-18. "... two 3D TRC systems are compared with one reference 2D equivalent system..." What is this equivalence? What parameters is it characterized by?
lines 37-38 and more below. In the introduction, you repeatedly refer to the figures placed in the main part of the article. This is not accepted in the scientific literature. It is advisable to shorten the introduction and eliminate the need for such references.
The forms similar to the used in the lines 51, 54: "[21] investigated ..." usually not used in scientific articles
line 57. Please, explain how the equivalency between 3D and 2D textile reinforced composites is established
line 173. 3. Numerical model. The authors discuss the features of a layer-wise modeling approach from line 174 to line 213. But it is not clear to the reader, which numerical method will be used for analysis. At last, the authors report using a finite element package Abaqus and materials models. This part should be reduced by 5 or more times
lines 184-185. A schematic comparison between both TRC systems is shown in Figure 9. But Figure 9 demonstrates only one TRC system.
lines 186, 191. The terms " smeared", "semi-smeared" are not desirable at the modeling methods context
Figure 10. It requires much more detailed explanation and justification. What means the term "input layer"? Which experimental data are present in this plot? Where is reference to the source of these data?
Table 4 contains some rheological parameters of the model used. How were these values obtained? What their accuracy? The analytical formulation of this material model must be presented.
Table 5, which demonstrates the experimentally obtained averaged parameters of 3D knitted specimens at the tensile loading. All designations of material model parameters should be explained. It is unclear how all three Young's moduli can be determined by applying a tensile load only along the x axis.
Figs 15 - 17 show stress-strain curves when testing a group of samples. One can see a very wide range of the samples behaviour, but there is no statistical analysis in the text. Without such an analysis these results cannot be interpreted
All plots, which present the stress-strain diagrams are present poorly. The lines in the plots take up little space, whereas the legends are very large.
The results of finite element modeling are inconclusive, since they use the simplest, unreal geometry of the structure of reinforced material. The Abaqus package provides a very wide range of options, but they are not used. The source of the parameters of the material model used is unclear.
The text is very sloppy arranged, it can be reduced twice without loss of the its significance. Serious revision of the text, careful formulation of the justifications for the assumptions made and the conclusions drawn are required.
Author Response
Dear reviewer, the authors would like to thank you for the very valuable comments you provided to the manuscript, they have been seriously taken into consideration in the hope to increase the manuscript’s quality and align closer with the wishes of all reviewers. For this purpose, different changes have been conducted throughout the document. Attached you will find the new manuscript with all changes tracked for ease of understanding. Also a document is attached with a point-by-point response to the reviewer's letter.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Dear authors! The text of the article is significantly improved. However, please consider the comments below.
lines 77-87. In this part of the paper the authors reference to the results early obtained by the another investigators. But it's not clear, how these results influenced the selection of the materials and testing methods presented in this article.
Figure 5. This photo is not informative. Perhaps it is worth complementing it with a sketchy image?
Figures 10, 11,12. These pictures show the experimentally obtained stress-strain curves with a considerable scattering and the so-named averaged curves consisting of three straight lines. Obviously, these differently oriented straight lines cannot be obtained by using some simple numerical averaging of the scattered testing results. The boundaries and orientations of each linear element of the "averaged curve" are important because they characterize changes in the behavior of the material. Thus, it is necessary to use some assumptions to reconstruct these three-element curves. Please, inform readers of these assumptions.
Figure 12. The legends of 3D Woven along x and 3D Woven along y do not indicate the type of lines.
Figures 13 and 14 show the three-element "averaged dependencies" with non ideally linear second section: 3D Knitted AVG (Fig.13) and 2D-EQ AVG (Fig.14). Please, explain the numerical technique used to reconstruct the transition between sections.
Figs. 10-15. I am forced to repeat my previous remark. Reducing the area occupied by graphics due to the use of large legends is undesirable.
Author Response
Dear reviewer, the authors thank you for these final comments. Below you can find a point by point answer to your requests.
Dear authors! The text of the article is significantly improved. However, please consider the comments below.
lines 77-87. In this part of the paper the authors reference to the results early obtained by the another investigators. But it's not clear, how these results influenced the selection of the materials and testing methods presented in this article.
Dear reviewer, these references have been added for completeness and to give context to the statement in line 77: “Conversely, the knitted 3D textiles were styrene-butadiene coated.” They did not influence the selection of materials or testing methods, however they supported the results in lines 233-235: “Additionally, the lower pull-out stress of the woven 3D compared to the knitted 3D (4.96 MPa and 4.82 MPa compared to 7.02 MPa) can be attributed to the lack of SBR coating of the woven 3D layup, as concluded in [20].” Here however, the references have been all added in line 235 in order to avoid confusion.
Figure 5. This photo is not informative. Perhaps it is worth complementing it with a sketchy image?
This is a sound comment, the authors have decided to remove the image of the mortar casted in the mould and instead replace it with an image of the cut specimens. The references in the text have been adapted accordingly, as well as the caption of the figure.
Figures 10, 11,12. These pictures show the experimentally obtained stress-strain curves with a considerable scattering and the so-named averaged curves consisting of three straight lines. Obviously, these differently oriented straight lines cannot be obtained by using some simple numerical averaging of the scattered testing results. The boundaries and orientations of each linear element of the "averaged curve" are important because they characterize changes in the behavior of the material. Thus, it is necessary to use some assumptions to reconstruct these three-element curves. Please, inform readers of these assumptions.
Dear reviewer, the authors have provided an explanatory text on how the averaged tri-linear curves are constructed: for the tensile case this is found in lines 167-173. For the flexural experiments it can be found in lines 245-250.
Figure 12. The legends of 3D Woven along x and 3D Woven along y do not indicate the type of lines.
The type of line has been made clearer in the legend and the legend has been placed next to the graph to increase the visibility of the results?
Figures 13 and 14 show the three-element "averaged dependencies" with non ideally linear second section: 3D Knitted AVG (Fig.13) and 2D-EQ AVG (Fig.14). Please, explain the numerical technique used to reconstruct the transition between sections.
The construction of the averaged curves has been added in lines 245-250. The curves are constructed as a linear combination of the following points: (i) point of zero loading (0,0), (ii) force and displacement at first significant load drop (Fc,dc), (iii) force and displacement at the end of the multiple cracking (last significant load drop) (Fmc, dmc) and (iv) stress and strain (Ff, df) at initiation of pull-out. A last linear branch was added in the flexural curves to account for the large pull-out strains observed in bending (compared to tension). Each point is obtained from an average of all experimental results.
Figs. 10-15. I am forced to repeat my previous remark. Reducing the area occupied by graphics due to the use of large legends is undesirable.
The authors apologize for this. All legends were moved next to the graphs and where necessary, the axes boundaries were fitted to better represent the experimental results.
Again, the authors would like to thank the reviewer for the valuable contribution to the manuscript.
