Numerical Analysis of Edge Cracking in High-Silicon Steel during Cold Rolling with 3D Fracture Locus
Round 1
Reviewer 1 Report
General Comment: The authors have investigated the fracture locus of high-silicon steels by conducting a series of fracture tests and finite element simulations and the results reported herein highlight the importance of key parameters that have an impact on the cracking and fracture behavior of high silicon steel. The topic is of interest to the fracture community and will help in improving our understanding of the fracture behavior of steel. For the most part, the paper is well-written, however, there are certain limitations that need to be addressed by the authors.
Specific Comments:
- Lines: 29-31: The authors should provide the reasons and phenomena that lead to the development of microcracks at the edge of the strip.
- Lines 34-41: Please provide a schematic diagram for the discussion provided in these lines and also provide appropriate references.
- The authors have provided a limited number of references on fracture behavior and fracture modeling in the Introduction section. Moreover, discussion on the references presented is limited. It is suggested that the authors provide more references and also summarize the results to improve the motivation of this manuscript.
- The authors are requested to include the following key references on stress triaxiality in steels that are highly relevant to this study:
- (a) Sajid, H.U. and Kiran, R., 2018. Influence of high stress triaxiality on mechanical strength of ASTM A36, ASTM A572 and ASTM A992 steels. Construction and Building Materials, 176, pp.129-134.
- (b) Kang, L., Ge, H. and Fang, X., 2016. An improved ductile fracture model for structural steels considering effect of high stress triaxiality. Construction and Building Materials, 115, pp.634-650.
- (c) Sajid, H.U. and Kiran, R., 2019. Post-fire mechanical behavior of ASTM A572 steels subjected to high stress triaxialities. Engineering Structures, 191, pp.323-342.
- (d)Wen, H. and Mahmoud, H., 2016. New model for ductile fracture of metal alloys. I: Monotonic loading. Journal of engineering mechanics, 142(2), p.04015088.
- (e)Jiang, W., Li, Y. and Su, J., 2016. Modified GTN model for a broad range of stress states and application to ductile fracture. European Journal of Mechanics-A/Solids, 57, pp.132-148.
- (f)Zhu, Y. and Engelhardt, M.D., 2018. Prediction of ductile fracture for metal alloys using a shear modified void growth model. Engineering Fracture Mechanics, 190, pp.491-513.
- The authors should provide stress triaxialities of the specimen’s configuration provided in Section 3.2 and Figure 3, or notch tensile values in tabular form as well (as provided in the above-mentioned references a, b, and c). Moreover, please discuss the rationale behind selecting the notch tensile values and the notch shaped adopted in the specimens in the manuscript.
- In tensile tests, the authors used the cross-head speed to measure the strain which might include inaccuracies due to the slipping of specimens during gripping and includes strains beyond the gauge section. The authors may compare the strain values with the strain values reported in the above-mentioned references (a,b,c) wherein similar kind of specimens with notches of different shapes and sizes are used and the strains are measured using a contact extensometer. For future studies, the authors should use a contact or non-contact extensometer to measure strain instead of crosshead speed.
- The stress-strain calibration is reasonable when both the models are combined. However, in Figure 4(a), it is not clear how the necking point initiation is decided.
- Please provide the chemical composition of the steel used in this study. Moreover, the authors should provide the standard to which this steel conforms (e.g. ASTM).
- Line 86-87: Please provide a reference for this statement.
- Lines 221-231. The authors have used appropriate mesh refinement in the vicinity of notches. Instead of providing the number of elements used, the authors should provide the element length used in the refined mesh portion of the model.
- The diagrams provided in Figure 8 are very well-drawn. Overall, the results from the experiments and the FE models have a reasonable match.
- The conclusions are concise and well-written. It is highly recommended that the authors add an “application” section after the conclusions section to discuss the application of this work and the results obtained from this study. This will improve the readership and practical application of this work.
The reviewer appreciates the authors' efforts and looks forward to receiving the revised manuscript.
Comments for author File: 
Comments.pdf
Author Response
Dear Sir
I submit a revised manuscript for publication in the Applied Sciences titled “Numerical Analysis of Edge Cracking in High-Silicon Steel during Cold Rolling with 3D Fracture Locus.”
Authors deeply appreciate the reviewer's valuable comments on the manuscript (applsci-1352758). We hope you will find our reply on the comments and the consequent modifications. Sentences or revised words are displayed on a yellow background in the revised manuscript.
Please do not hesitate to contact me if you need any further information. I hope that this revision and complemented contents are satisfactory so that the revised version will be acceptable for publication in the Applied Sciences.
Yours sincerely,
Youngseog Lee, Ph.D
Professor
Department of Mechanical Engineering,
Chung-Ang University,
Seoul, 156-756, Korea
E-mail: [email protected]
Author Response File: Author Response.pdf
Reviewer 2 Report
The present paper shows a numerical-experimental study on the fracture mechanics of silicon steel during cold rolling. The study is well designed and presented and deserve publication after addressing the following comments:
page 2 line 66: the manufacturing process may also lead to the developement of residual stress. While in same case residual stress could be beneficial if compressive, the stress around the crack tip could be further icnreased by residual stress. Please add a comment on this aspect and cite the following reference.
[1] Fratini, L., Macaluso, G., Pasta, S. Residual stresses and FCP prediction in FSW through a continuous FE model (2009) 209 (15-16), pp. 5465-5474
[2] Marannano, G.V., Mistretta, L., Cirello, A., Pasta, S.Crack growth analysis at adhesive-adherent interface in bonded joints under mixed mode I/II (2008) 75 (18), pp. 5122-5133.
page 2 line 84: please consider to rename the section as "Description of Roll bending"
page 3 line 110: please specify how the strain was measured. Did author used an optical method or strain gauge?.
page 4 line 130. please specify the constitutive behavior of the silicon steel. Is this an exponential form as a hyperlastic material.
page 5 line 149: Figure 4 is shown before showing the features of the finite element model. Please consider to move this part after the presentation of finite element model.
page 7 line 14: More details on the FE model needs to be reported. 1) Please specify if convergence was done to assess the optimal number of elements. 2) Please motivate the utilize of reduced integration. This decreases the accuracy in the stress prediction as compared to the C3D8 element type. 3) Please state if sensitivity analysis was done on the material parameters and model setting (ie, damping or mass scaling, and simulaiton time) to demonstrate the model capability.
Page 8 line 260: Figure 6 shows a kind of residual plasticity. Did author performed cyclic testing (loading and unloading) to test if the slope of stress-strain curve (ie, Young modulus) remains stable over cyclic testing?. please clarify this aspect
Author Response
Dear Sir
I submit a revised manuscript for publication in the Applied Sciences titled “Numerical Analysis of Edge Cracking in High-Silicon Steel during Cold Rolling with 3D Fracture Locus.”
Authors deeply appreciate the reviewer's valuable comments on the manuscript (applsci-1352758). We hope you will find our reply on the comments and the consequent modifications. Sentences or revised words are displayed on a yellow background in the revised manuscript.
Please do not hesitate to contact me if you need any further information. I hope that this revision and complemented contents are satisfactory so that the revised version will be acceptable for publication in the Applied Sciences.
Yours sincerely,
Youngseog Lee, Ph.D
Professor
Department of Mechanical Engineering,
Chung-Ang University,
Seoul, 156-756, Korea
E-mail: [email protected]
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have addressed all the comments and suggestions of this reviewer and the paper is now acceptable form for publication in this journal.
Reviewer 2 Report
all comments were addressed and the paper deserves publication
