Research on the Bending Fatigue Property of Quenched Crankshaft Based on the Multi-Physics Coupling Numerical Simulation Approaches and the KBM Model
Round 1
Reviewer 1 Report
The paper by Songsong et al. is devoted to multi-physics numerical simulations of the crankshaft quenching processes and bending fatigue. The paper is written in a manner which is not easy to understand and follow and its scientific novelty is not clear. The paper can be recommended for publication only after major revision, careful English language improvements and if editor considers it appropriate that the article contains pure engineering exercises with no scientific novelty.
Comments from the reviewer:
- Careful language proofreading must be performed. Below are only a few examples:
- Line 9: "As a result of this..." result of what?
- L.11: "In this paper, the research aim of this paper..."
- L.16: Abbreviations like KBM need to be spelled out.
- L.23-25: The sentence is not good formulated.
- L.86: thermo-mechanical.
- L.89-90: parameters is not a suitable word in this case since model is not a model itself, as well as stress field.
- L.99: crankshaft is not a part of equipment.
- L.107: a new paragraph probably needed where the discussion on the material begins.
- L.117: Is depended -> depends.
- L.118: Expression ... expressed.
- L.122-124: "value" sounds more scientific than "amount" in the context.
- Dots in figure names should be after the figure number (Figure 1. Blah blah blah...)
- L.153 time length?
- L.178. "...stress will be created..." doesn't sound right.
- L.260. How can the function be solved?
- L.300: temperature declined?
- Many more...
- L.37-39: It isn't actually Wang's [8] finding that fatigue fracture often initiates on surfaces and surface treatments help to improve the fatigue strength.
- Why is the thermo-mechanical coupling not considered on the heating up stage? Would this affect the final solution drastically?
- L.123-125: Difficult to understand why total equivalent strain is equal to dynamic failure strain.
- Fatigue limit load is considered without number of life cycles. What is the meaning of fatigue strength without defined amount of life cycles/lifespan?
- Description of the FE models is not comprehensive. The amount of elements, their type, boundary conditions should be reported in full, as well as possible convergence studies, justification of the use of only quarter of the crankpin model etc. Figure 2 is completely uninformative and should be redrawn.
- There is no explanation of what is depicted on the right of the Figures 3 and 4. No FE-model is reported before about the fillet. Also a general picture of the crankshaft would be informative to understand what is what.
- Figures 3,4,5,8: text isn't recognizable
- L.215: "all material constants" must be defined as well.
- L.216: Authors claimed for several times that the stress-strain fields are complex and not uni-axial and still use only shear. Comment please.
- Fig.9: Crankshaft or crankpin?
- Section 3.3. Why did the authors consider only one crankpin and not the entire crankshaft? Would the results be totally different?
- Section 3.3. How do authors justify the choice of bending moment value 1000 N*m?
- L.265: Fatigue strength w/o number of cycles again, what is this? There are some load cycles reported in the experiment, but no comparison with theoretical calculations was made.
- L.281: How did the authors understand the the distribution is normal here?
- L.298: time of 12 seconds have not been reported before.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Dear Authors Your paper can be interesting to readers but in present form it is impossible to be published. First of all there are some lack that have to be corrected.
- Chemical composition was tested by You? How it was obtained, do it meet the standard?
- Why do You present figure 1? It do not bring nothing to the paper.
- What software do You use?
- Figures 2, 6, 8 and 9 are illegible.
- Boundary conditions where did they come from?
- How were applied materials parameters to the simulation? There no such information!
- In the paper it cannot be said there are a result discussion. This have to be corrected!
- There are no conclusions!
- To many self citation!
- Referenced almost only from China, this not acceptable.
After general corrections the paper can be one more time reviewed, but in this form it do not meets the publication requirements.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The present manuscript studied quenched crankshaft bending fatigue properties. I recommend the paper for publication after major improvements. The paper reports an interesting and very useful work, well structured in the manuscript, but the manuscript has some weaknesses. Mentioned below aspects must be taken into consideration during the revision:
Nomenclature:
(1) I suggest adding "Nomenclature" section (with units and abbreviations) in the manuscript.
(2) The authors use the term "KBM model" by Kandi-Brown-Miller nowhere without the full name and without citing the source. Please complete the information.
Introduction:
(3) As a crankshaft is subject to operating loads, the induced stresses at these high stress concentration areas could initiate fatigue cracks and lead to catastrophic failure.
More discussion about the fatigue behaviour should be added. Especially connected with modelling techniques about the equivalent stress intensity factor range, residual stresses or operating stresses etc.
(4) Literature analysis should be expanded. A lot of works dealing with this issue have been published (with an emphasis on the practical side), especially in Metals journal.
Materials and Methods:
(5) How were the chemical composition of 42CrMo obtained? From literature or determined by the authors for the tested material? Not clear;
(6) Please correct the grade of the material in table 1.
(7) Please provide information source about mechanical parameters from literature (if any);
(8) Morphology and metrology of the surface - is it possible to:
(a) show SEM images of the fracture;
(b) measure the surface topography for analysis?
Do you have information about the surface roughness of fractures?
(9) The bending fatigue experiment equipment information should be moved to this section.
(10) It would be advisable to show the whole method algorithm in a flowchart.
Results:
(11) The main limitations of the present method must be identified and discussed in the end of this section.
Conclusion:
(12) The conclusions should be in a quantified form.
References:
(13) References section should be extended. I propose to add a few entries in the Introduction section regarding the crankshaft failure with fatigue condition analysis (Aliakbari et al., 2022; Fonte et al., 2017); crack closure modelling (Antunes et al., 2015); and fracture surface analysis (Macek, 2021).
- Aliakbari, K., Nejad, R.M., Toroq, S.K.P., Macek, W., Branco, R., 2022. Assessment of unusual failure in crankshaft of heavy-duty truck engine. Engineering Failure Analysis 134, 106085. https://doi.org/10.1016/J.ENGFAILANAL.2022.106085
- Antunes, F. v., Camas, D., Correia, L., Branco, R., 2015. Finite element meshes for optimal modelling of plasticity induced crack closure. Engineering Fracture Mechanics 142, 184–200. https://doi.org/10.1016/J.ENGFRACMECH.2015.06.007
- Fonte, M., Infante, V., Reis, L., Freitas, M., 2017. Failure mode analysis of a diesel motor crankshaft. Engineering Failure Analysis. https://doi.org/10.1016/j.engfailanal.2017.06.010
- Macek, W., 2021. Fracture Areas Quantitative Investigating of Bending-Torsion Fatigued Low-Alloy High-Strength Steel. Metals 2021, Vol. 11, Page 1620 11, 1620. https://doi.org/10.3390/MET11101620
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
- "According to the fatigue damage theory, the fatigue property of a given component depends on two parameters: the equivalent stress or strain state based on a proposed model and the fatigue property of the material. In other words, for two components made by the same material under the fatigue limit condition, the equivalent stress or strain of them should be the same if the fatigue damage models were the same. So in this paper, the equivalent strain of the crankshaft under the fatigue limit load is the same to that the material under the fatigue strength. The reason has been added in the revised paper."
I do not see how this was clarified in the revised version. I think the authors mean that the fatigue damage occures when total equivalent strain is equal to dynamic failure strain. Please rephrase this paragraph to make it more understandable for a reader.
- What is the reason to list the electrical resisitivity for the material (table 3)?
- Is Figure 12 invisible? Plase check your manuscript before submitting!
- Page 11, bottom: Figure 2?
- Figures 7,8,9: the font is not easily readable.
- "Response: The distribution property of the fatigue limit load of the steel crankshaft under the
specified fatigue life (107) can be expressed according to the Gaussian distribution function"
More details on this should be added to the manuscript (may be a plot of the distribution as well).
- The authors' English still needs to be improved. In the first review, I only pointed out a few mistakes/misprints. Proper proofreading must be performed before publication.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Dear author
The paper In this form cannot be published. First of all the text have to be reread and corrected (for example line 156 is 42CrMo, but in table 1 there is 42CoMo). Moreover Authors in point 8 of responses have wrote that conclusions have been rewritten but in text there is no such point! Read the text carefully and correct it.
Author Response
Response to the reviewer
Thanks for the comments. After consideration, we converted the fourth part of the paper to the conclusion part because that in the end of the third part, detailed discussion of the prediction results had already been proposed. In the newly added conclusion part, the research results are expressed with short sentences and paragraphs. In addition, some further work plan are also added in this part based on the discovery during our research.
Reviewer 3 Report
The authors attempted to provide a revision manuscript according to the reviewers' comments. They also responded to all cases individually. Although not all of their answers were satisfactory, they are generally acceptable in the scoring.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
In this form the paper can be published
Author Response
Thanks for your comments.
