Numerical Simulation and Multi-Objective Optimization of Partition Cooling in Hot Stamping of the Automotive B-Pillar Based on RSM and NSGA-II
Round 1
Reviewer 1 Report
The manuscript entitled ‘Numerical Simulation and Multi-objective Optimization of Partition Cooling in Hot Stamping of the Automotive B-pillar Based on RSM and NSGA-II’ falls within the scope of the journal Metals. The paper contains very interesting numerical and experimental results as well as optimization procedures. It is of sufficient scientific interest and has originality in its technical content to merit publication. The authors have cited the relevant literature. Methods, interpretations of results and conclusions are correct and novel. The issues were well presented. In terms of content, the analysis does not raise any objections. The arrangement of work maintains substantive continuity and constitutes a logical whole. The manuscript (after minor corrections in References – author lists and journal names should be in accordance with the template) is suitable for publication in its present form.
Author Response
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Reviewer 2 Report
The authors present an interesting approach to optimize the process parameters in hot stamping of an automotive part. The authors investigate an innovative process where the cooling conditions depend on the part areas so as to confer to the material adequate mechanical properties. The optimization procedure is clearly implemented with a multi-objective function based on several process parameters which can greatly influence the final part shape and microstructure. The study is conducted with great care and offers results of very high plausibility, hence, I tend to support publication of this work. I see room though for some revision and improvements.
1-Typographical errors:
-line 6, “and” is written twice.
-line 93: “stampede” instead of “stamped”.
2-In the manuscript, the authors focus on the cooling phase of the process and no information is provided on the forming stage. To what extent can the forming operation influence the cooling one ? Are residual stresses important in the blank at the end of the forming stage ? Did you also simulate the forming operation ?
3- The cooling operations are quite complex to implement, because the cooling rate has to be accurately controlled to have adequate mechanical properties in each part of the pillar. The upper and lower parts of the die have not been explicitly taken into account in the paper. Nevertheless, the tool and the materials used for its manufacturing have to play an important role in the final mechanical properties of the part. Indeed, during the cooling phase, interactions between the die and the sheet are complex and the thermal contact resistance is not easy to assess. Moreover, the thermal conductivity of the tool can greatly influence the temperature field evolution of the blank during cooling. Therefore, could the authors give more information on the tools ?
4- In Eq 2-5, how have the coefficients been identified ? How do you justify the number of significant digits that you consider for each of them?
5- There is a mistake in the title of Fig.8
6- In your simulations, have you evaluated part distortion after trimming. Did your optimisation procedure can be used to control (and minimize) springback effect after trimming ?
Comments for author File: Comments.pdf
Author Response
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Reviewer 3 Report
The paper consists of a numerical simulation of the behavior of the automotive B-pillars during cooling. From a simulation methodology point of view it is well developed and consistent. The methodology used is not original but it is certainly well used.
The work is well written and the figures and the tables are of good quality, apart from small inaccuracies (see below).
In figure 6 b the vertical axis must be corrected.
Author Response
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