# Open Review of "Comparison between 2D and 3D fiber-matrix debonding simulation for inverse identification of interface fracture properties"

Hugo Girard, Aurélien Doitrand, Behrad Koohbor, Renaud Rinaldi, Nathalie Godin, Jérôme Bikard, Julien Réthoré

► To cite this version:

Hugo Girard, Aurélien Doitrand, Behrad Koohbor, Renaud Rinaldi, Nathalie Godin, et al.. Open Review of "Comparison between 2D and 3D fiber-matrix debonding simulation for inverse identification of interface fracture properties". 2025. hal-04996881

HAL Id: hal-04996881

https://hal.science/hal-04996881v1

Submitted on 26 May 2025

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Distributed under a Creative Commons Attribution 4.0 International License
Identifiers

Open Review

OAI hal-04996881

Reviewed Article

DOI 10.46298/jtcam.12997

Licence

CC BY 4.0

©The Authors

# Review of “Comparison between 2D and 3D fiber-matrix debonding simulation for inverse identification of interface fracture properties”

Hugo GIRARD<fnref n="1" />,<fnref n="2" />, Aurélien DOITRAND<fnref n="1" />, Behrad KOOHBOR<fnref n="3" />, Renaud RINALDI<fnref n="1" />, Nathalie GODIN<fnref n="1" />, Jérôme BIKARD<fnref n="2" />, and Julien RÉTHORÉ<fnref n="4" />,<fnref n="5" />

## Review of version 1

Permalink: hal-04431332v1

**Authors** We would like to thank the reviewers for their comments which were very helpful to improve the quality of the manuscript. We carefully considered all the comments and addressed them in the manuscript.

## Reviewer 1 (Anonymous)

**Reviewer** This work adopts 2D and 3D finite element (FE) model to investigate the stress and failure process of fiber interface. The feasibility of the two FE models on predictions of stress field, damage initiation and development are assessed. Based on the numerical studies, a methodology is developed to inversely identify fiber/matrix interfacial fracture properties. This work is interesting and may provide some useful information for determining interfacial properties experimentally. I recommend it to be published in the journal after the following comments are considered.

**Authors** We thank the reviewer for his/her positive appreciation.

**Reviewer** The conclusion section is too long and it is hard to follow for readers. I suggest the authors only list the key conclusions drawn in this work. The details about numerical simulation and some less important results may not be necessary to keep.

**Authors** We have clarified and shortened the conclusion as suggested by the reviewer.

**Reviewer** In this work, the numerical studies are based on a composite with macro-scale glass fiber embedded in the matrix. Considering the glass fiber in realistic composite has a diameter of ~ 10 µm. Are the present analysis are still valid for realistic composites?

**Authors** The current numerical analysis remains valid regardless of the sample size, provided it agrees to the principles of continuum mechanics. However, the experimental setup required for realistic composites differs significantly. For instance, front-surface observations must be conducted using a scanning electron microscope with a specialized speckle pattern. Establishing such a setup causes considerable challenges. Furthermore, assessing the complete debonding topology necessitates the use of computed tomography scanning, which typically requires a penetrant to highlight the debonding locations.

We have added a sentence to the conclusion on this aspect: Page 19: “Overall, the numerical

<footnote n="1">¹ Univ Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS, MATEIS, UMR5510, Villeurbanne, France</footnote>

<footnote n="2">² Axel'One (Solvay), Saint Fons, France</footnote>

<footnote n="3">³ Department of Mechanical Engineering, Rowan University, USA</footnote>

<footnote n="4">⁴ Nantes Université, École centrale Nantes, CNRS, GeM, UMR 6183, Nantes, France</footnote>

<footnote n="5">⁵ Editor</footnote>
approach can be extended to more realistic composite configurations, including those with fiber diameters of just a few microns. However, for smaller fibers, a scanning electron microscope would be necessary to accurately characterize the debonding process."

## Reviewer 2 (Anonymous)

**Reviewer** The article is well written and presented and concludes the previous work of the authors on this topic, and it is relevant to the journal's readership. Few comments and suggestions are given below for the authors to consider and account in the revised manuscript before any publication.

**Authors** We thank the reviewer for his/her positive appreciation.

**Reviewer** Abstract → 1st line: "Fibre-matrix debonding..." Please indicate that your article is about transverse debonding and not longitudinal debonding from the get-go. Also mention this in first sentence of your Conclusion section.

**Authors** We have modified the abstract and conclusion to specify that we work with transverse fiber. Page 1: "Fiber-matrix debonding in single transverse fiber specimen is studied experimentally..." Page 18: "Initiation of fiber-matrix debonding was assessed using 3D and 2D models and the CC on a single transverse fiber configuration."

**Reviewer** Introduction → "However, the aforementioned..." Try to cite more recent papers such as: https://journals.sagepub.com/doi/10.1080/09506608.2023.2265701

**Authors** We have modified the introduction to include more recent publications and add another reference (Pitkethly et al. 1993). Page 1: "These approaches are reviewed in AhmadvashAghbash et al. 2023 and primarily focus on shear interface characterization." Page 1: "However, the aforementioned methods lead to a significant variability in measured properties, as illustrated in Pitkethly et al. 1993." Page 1: "one can mention: pull-out (Zarges et al. 2018) and microbond tests (Lee et al. 2024), single fiber fragmentation test (see Van Der Meer et al. 2019), and..."

**Reviewer** 3D numerical model: Fig. 1 → Where is the center? The annotation of the figure itself is wrong?!

**Authors** We have modified the text and figures by replacing "center" with "mid-plane". Figure 1: "Sample mid-plane" Figure 2: "Mid-plane" Page 9: "While it accurately describes the fields around the specimen [mid-plane,...]"

**Reviewer** The last line of section 2.1. → "... for fixed areas are smaller than 1.5%." Where does this come from? Any references?

**Authors** This result comes from a mesh convergence analysis. In our case, we select a mesh that produces a maximum difference of 1.5% with a converged solution (finer mesh). We have clarified the sentence. Page 4: "A subsequent campaign is conducted to assess the mesh size used to compute the variation in the elastic strain energy. The size chosen ensures a difference in released elastic strain energy for fixed areas is smaller than 1.5% compared with a converged solution."

**Reviewer** Fig. 8, 9, 10 (or any other similar figure) → the axis can be better understood at first glance if the unit is changed to micrometres instead of [mm×10²].

**Authors** We have homogenized the figures so that we only have micrometres.

**Reviewer** Comment on what would be the expected crack front topology in the presence of neighbouring intact fibres!

**Authors** We have added a sentence to the conclusion on this aspect: Page 19: "In addition, neighboring fibers could also be considered to mimic the real microstructure of composites. They would influence the crack path and the intensity of the stress and energy fields, as observed in Girard et al. 2024."

## Other modifications

**Authors** We have added a reference to the review of the coupled criterion recently published in JTCAM: Page 2: "The Coupled Criterion (CC), introduced by Leguillon 2002, can also assess debonding
initiation, propagation and predict the associated loading and size, see *Doitrand et al. 2024*." We have changed the colours of Figures 14 and 15 to make them more readable in black and white. We have also modified the legend to specify that these are the experimental boundaries. We have modified Table 2 to specify every time that it is in 2D.

**Editor (Julien RÉTHORÉ)**

The article proposed by the authors corresponds perfectly to the journal's expectations in terms of topics and quality. The reviewers offered constructive feedback, suggesting only minor modifications to the article. The authors carefully considered these suggestions and incorporated them into a revised version of the article. Consequently, the decision was taken to accept the paper for publication in its revised form without hesitation.

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