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Peer review report 5 on “A grain based modeling study of mineralogical factors affecting strength, elastic behaviour and micro fracture development during compression tests in granites”
Engineering Fracture Mechanics 133 Supplement 1 (2015) 250
Contents lists available at ScienceDirect
Engineering Fracture Mechanics journal homepage: www.elsevier.com/locate/engfracmech
Peer Review Report
Peer review report 5 on ‘‘A grain based modeling study of mineralogical factors affecting strength, elastic behaviour and micro fracture development during compression tests in granites” Original Submission Recommendation Publish after minor amendments Comments to the author The authors have established a discrete element grain based model to study the rock properties and micro and macro crack propagation of certain granites. The numerical model was calibrated to distinct lab tests, and the numerical results agreed with major laboratory observations. Interesting results have been obtained. However, limitations are also seen from the current numerical model. Remarks 1: In the numerical model, the minerals of granite were represented by polygons (grains) whose sizes are determined by other studies, for instance, reference [44] and [45]. And the grains consist of circular particles. It is shown that distribution of particles and particle sizes have great impact on fracture development and caused mismatch in rock strength as compared with lab test results. Hence, the authors are invited to explain how to determine the amount of particles in one grain? In one model, is the particle density identical for different minerals? Remarks 2: It is mentioned in the paper ‘‘When a mineral consists of more particles, the stress is distributed over more contacts and the strength of each contact must be smaller to match the ‘‘macroscopic” strength of a mineral”. Given the fact that there exist many grains of one mineral type but of different sizes, how do the authors determine the strength of the contact to make sure that ‘‘macroscopic” strength of a certain mineral is constant? Remarks 3: Please add explanation to the abbrevation ‘‘DFN” in the ‘‘INTRODUCTION” section. The authors are invited to check again the expressions to eliminate misunderstandings. For instance, the sequence of 3 mineral size distribution scenarios in Fig. 10 is not in accordance with the description in the following paragraph: in the paragraph, Scenario 3 is described as ‘‘. . .without standard deviation. . .”. However, this case corresponds to Scenario 2 in Fig. 10.
Xiang Li Gustav-Zeuner-Strasse 1 Freiberg Germany
DOI of published article: http://dx.doi.org/10.1016/j.engfracmech.2015.09.008
http://dx.doi.org/10.1016/j.engfracmech.2015.09.036
Contents lists available at ScienceDirect
Engineering Fracture Mechanics journal homepage: www.elsevier.com/locate/engfracmech
Peer Review Report
Peer review report 5 on ‘‘A grain based modeling study of mineralogical factors affecting strength, elastic behaviour and micro fracture development during compression tests in granites” Original Submission Recommendation Publish after minor amendments Comments to the author The authors have established a discrete element grain based model to study the rock properties and micro and macro crack propagation of certain granites. The numerical model was calibrated to distinct lab tests, and the numerical results agreed with major laboratory observations. Interesting results have been obtained. However, limitations are also seen from the current numerical model. Remarks 1: In the numerical model, the minerals of granite were represented by polygons (grains) whose sizes are determined by other studies, for instance, reference [44] and [45]. And the grains consist of circular particles. It is shown that distribution of particles and particle sizes have great impact on fracture development and caused mismatch in rock strength as compared with lab test results. Hence, the authors are invited to explain how to determine the amount of particles in one grain? In one model, is the particle density identical for different minerals? Remarks 2: It is mentioned in the paper ‘‘When a mineral consists of more particles, the stress is distributed over more contacts and the strength of each contact must be smaller to match the ‘‘macroscopic” strength of a mineral”. Given the fact that there exist many grains of one mineral type but of different sizes, how do the authors determine the strength of the contact to make sure that ‘‘macroscopic” strength of a certain mineral is constant? Remarks 3: Please add explanation to the abbrevation ‘‘DFN” in the ‘‘INTRODUCTION” section. The authors are invited to check again the expressions to eliminate misunderstandings. For instance, the sequence of 3 mineral size distribution scenarios in Fig. 10 is not in accordance with the description in the following paragraph: in the paragraph, Scenario 3 is described as ‘‘. . .without standard deviation. . .”. However, this case corresponds to Scenario 2 in Fig. 10.
Xiang Li Gustav-Zeuner-Strasse 1 Freiberg Germany
DOI of published article: http://dx.doi.org/10.1016/j.engfracmech.2015.09.008
http://dx.doi.org/10.1016/j.engfracmech.2015.09.036