New Die-Compaction Equations for Powders as a Result of Known Equations Correction—Part 3: Modernization of Plasticity Equations for a Porous Body
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper presents the derivation and experimental validation of a new analytical equation for the compression curve of powders with plastic behaviour. A continuum model of a porous material that was published in previous parts of this work is extended. The manuscript is very well written and the work has very interesting and new results, which are important for the field of powder mechanics. However, the minor improvements of the manuscript are necessary. After improvent,, I can strongly recommend this paper for publication.
General questions and recommendations
1) I believe the author makes a good contribution to the improvement of knowledge in the field of powder compaction. However, the used continuum approach has some assumptions that will no longer valid if the powder and packing are inhomogeneous or consist different materials. There are discrete approaches in the literature, such as the Discrete Element Method (DEM), which considers the individual properties and packing structure, e.g. in Hesse, R. et al. in Advanced Powder Technology 34 (2023) 104062 an elastic-plastic model for the particles were used to simulate the plastic behavior during compaction. Can you mention and shortly discuss this alternative with DEM in the introduction of your paper?
2) Figure 3.2 shows experimental results at different temperatures. How was plastic deformation measured? At which yield point does it start? What is the unit of "plastic deformation"? Please complete the manuscript with the description of the experimental method, setup and parameters used, if the experiments have not been published previously.
3) It is not clear why temperature was used as an influencing parameter in experiments. No temperature was considered in the model. The dependency of the yield strength on the temperature for the studied materials of powders can be known. Does it agree with your measurement?
4) Can you compare the compression curves according to your model with the measured curves presented in Fig. 3.2?
5) Can you calculate the compressibility C, which was defined for example in work of Kawakita, K., Lüdde, K.-H.., Powder Technology 4, 61 (1971) that you also considered, from your experimental data of the compression curve and compare it with the compressibility of your model. Can you categorize powders studied in your work according to the compressibility index groups, e.g. according to Tomas, J. in Chem. Eng. Technol. 27 (2004)?
6) The powder compaction of powder in roll compacter will be usually described by Johanson's compaction model (ASME J. Appl. Mech., E32 (1965)). This Eq. is similar to the model of James, P. J. (1977), but with the exponent of 1/m. This well know model was modified e.g. in Yu Liu, Carl Wassgren, Powder Technology, Vol. 297 (2016). Can you compare and discuss the difference of your equation with this well know Johanson's model?
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe topic is interesting and there is a huge amount of work presented. However, the structure should be improved to clearly show the scientific context, the goal of the paper, and the novelty.
For example, it is usually expected that the introduction presents the context based on the literature review. There is practically no literature review here. Nothing on the standard analytical models for compaction like Kawatika or Heckel? What is the originality and interest of this approach? The appropriate references are given but along with the results only. Please make a real introduction with the references.
Then, the method should be introduced and finally the results presented and discussed.
Unfortunately, the weird structure of the paper make very difficult for the reader to understand the main points. Thus, I suggest that the paper be rewriten in the standard way before been considered for publication.
*in eq 21 22 23 24 the authors should give the references instead of the names of the authorrs
* From a personal point of view, i generally avoid to put equations in the abstract
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper discusses how adjusting two density-dependent parameters in equations for powder compaction processes (PCP) improves accuracy in modeling, highlighting two specific equations that provide highly accurate descriptions of PCP for various powders, including highly plastic and fine powders, with one equation showing particularly high determination coefficients in experimental data approximation.
This is a follow-up work by the author. Overall, the article is very good. Here are some minor suggestions for improvement.
1. It might be worth reconsidering the inclusion of formulas in the abstract, as their presence could potentially affect the article's initial readability for a broader audience. While the technical details are undoubtedly important, summarizing the key findings in a more accessible manner within the abstract could enhance the overall impact and accessibility of your work.
2. In the Introduction section, it would be beneficial to elaborate on the scientific significance of this study.
3. Line 90: Please try to avoid the use of the first person.
4. Line 141: “equation”-> “Equation” (The same applies below)
5. The Conclusion section should be further optimized. First, the scientific significance of the article should be summarized. Secondly, it should be clarified whether there will be subsequent research in this series, such as Part 4.
6. Currently, the entire article focuses on the discussion of theoretical formulas. Could you propose the prospects of applying this theory in relevant fields? Or will this aspect be addressed in Part 4?
Author Response
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Author Response File: Author Response.pdf
