Study on Ductility Failure of Advanced High Strength Dual Phase Steel DP590 during Warm Forming Based on Extended GTN Model

Round 1

Reviewer 1 Report

The paper "Study on ductility failure of Advanced high strength dual phase steel DP590 during warm forming based on Extended GTN model" presents the experimental investigation and finite element simulation of the warm deformation and fracture behavior of the dual phase steel. The authors have determined the dependence of shear damage parameters on the stress triaxiality values and shown a high accuracy of the constructed model. The paper may be accepted for publication. However, some points of the paper should be clarified accordingly following comments:

1.                 In the introduction part, the authors have not considered the application of the finite element (FE) method for the simulation of the deformation and fracture behaviour. It is recommended to analyze the papers devoted to the FE modelling (e.g.  10.1016/j.msea.2016.06.076, 10.3390/app11073204, etc.).

2.                 Using the tensile test, the authors have determined engineering stress-strain curves. However, equation (1) is for true stress and strain values. It is unclear how the authors recalculate the experimental curves because deformation localization may proceed during the tension. Additional information is required.

3.                 More information about finite element simulation (mesh size, boundary conditions, etc.) should be added to the manuscript.

4.                 The paper is overloaded by figures. Most of them are not properly discussed in the manuscript. It is recommended to remove unnecessary figures (e.g., part of figures 11-15, 18, etc.).

5.                 The language of the manuscript should be significantly improved.

6.                 Minor corrections:

-         How many samples were tested for each direction?

-         It is hard to read the paper because part of figures is not cited.

Author Response

Dear expert, thank you very much for your valuable comments. We have made serious modifications. The following documents are our revised manuscripts, and the modified parts are marked in red

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper presents the extension of the GTN model  to the failure prediction of DP590 steel under warm forming.

The paper is based on experimental tests and numerical model optimization.

The paper results too dense of models and results and very difficult to read.

The structure of the paper must be reviewed.

Main remarks

Section 4 Parameter calibration

- It is not clear when the parameter calibration is referred to GTN damage model and when is referred  Extended GTN damage model. The  the text is absolutely not clear.

-  central composite design,  response surface analysis method, ANVOA need  references

- Please evaluate to exclude from the paper Table 5, Table 6 Line 229-234

- Line 235 Finally, the damage parameter values under different temperatures are obtained by genetic algorithm, is this part of work reported in another paper? Please insert a reference or give short description of the used algorithm.

 

Section 5 verification and discussion

Line 272  "In this section, the damage parameters of the above test and calibration are numerically simulated by compiling VUMAT subroutine and using ABAQUS software to study  the ductile failure of DP590 at different temperatures." is this the same VUMAT of Line 236? Please clarify.

Line 304 "It can be seen from the above figure" Please refer in detail to each figure.

Line 324 " It can be seen from the above figure" Please refer in detail to each figure.

Line 382 Discussion about numerical simulation diagram of tensile bending specimens with different  fillets is too brief, please evaluate if inlcude it in the paper or not.

Author Response

Dear expert, thank you very much for your correction. The following document is my reply. Thank you very much for your review. I have marked the correction in blue in the manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have made necessary modifications in the manuscript. The paper may be accepted for publication.

Reviewer 2 Report

Thanks for the revision