Effect of Strain Hardening Laws on Solution Behavior Near Frictional Interfaces in Metal Forming Processes: A Simple Analytical Example

Round 1

Reviewer 1 Report

The research topic is interesting and tries to seed light in experimental observations found in machining and forming processes. The results obtained are well formulated and moreover the structure of the manuscript is acceptable.

However, there are some points which are missing and hopefully the comments of this reviewer will help the authors to improve the quality of the manuscript.

The authors try to mathematically prove the reason for the generation of thin layers of intensive plastic deformation near frictional interfaces in metal forming processes. As the final conclusion they state that hardening laws which saturates are giving as a result sliding conditions equivalent to the hardened layers observed in the vicinity of frictional interfaces. One question that should be address is what happens in those areas that makes the material to behave in such a way. This may not be the main purpose of the work but a reasonable argumentation should be given to explain the concepts mathematically proven. For example, is there a temperature increment in such areas due to friction that makes the material to be softened? Because I guess that the hardened layers are also observed when materials with a high hardening capacity such as deep drawing steels are analysed. An extrapolation of the proved concept should be carried out.

Another point that could be address is the graphical representation of the mathematical models. There is a lot of information given in the equations but the reader could get lost without a graphical representation of the concepts. I believe that graphical schemas and graphical representation of the equations will improve very much the capacity of the readers to understand the concepts proved in the paper. I think this is a must for improving the quality of the paper, not of the work but yes of the paper.

I think that this is a valuable work that could be published after improving these two aspects of the paper

Author Response

Please see the file attached

Author Response File: Author Response.pdf

Reviewer 2 Report

Effect of strain hardening laws on solution behavior near frictional interfaces in metal forming processes: A simple analytical example

Sergei Alexandrov , Elena Lyamina , Pierre-Eves Manach

Article review:

The manuscript deals with an analytical problem involving maximum friction law as a boundary condition. An analytical solution to the presented problem is developed for 3 strain hardening laws. It is demonstrated that whether sticking or sliding occurs at the boundaries depends on the hardening law used. The authors show that only one of the hardening laws results in a singular-behavior equivalent strain near the friction surfaces. This is interpreted as a prediction of the generation of hardened layers in the material near frictional interfaces.

Minor issues:

• Line 80: the authors refer to hardened layers which are created near frictional interfaces following machining or deformation. Such phenomena are generally reflected in changes in the microstructure of the material. It would be helpful to provide such a representative example (a metallographic cut of a common material after plastic deformation, demonstrating the microstructural changes at the outer layer as a result of the high friction conditions during the deformation process).
• Line 81: The authors mention that standard tests are not representative of the bulk material behavior within the layers. At least one example of a test (such as hardness) and a characteristic sample depth should be provided.
• Can the authors show that when a solution is degenerated to a rigid perfectly plastic case, the solution is consistent with the one provided in literature?

Author Response

Please see the file attached

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper can be accepted in its present form