Improved FE simulation of the shear cutting process using a temperature and strain rate-dependent extension of the MMC model
Final Report Abstract
To develop a strain-rate and temperature-dependent MMC failure model, it is necessary to ensure high reproducibility by eliminating the influence of the machine on the process. Bearing clearances in knuckle-joint presses lead to an uncontrolled ram displacement during cutting processes. This has an impact on the quality of the cut surface of the finished components. Therefore, a system to compensate for the machine-dependent initial displacement was developed, constructed and integrated into the automated punching press, which makes it possible to compensate the bearing clearances and minimize the ram displacement. Using metallography images, it was possible to demonstrate an improvement of up to 10 % in the smooth cut percentage as a result of minimized ram displacement. Furthermore, a numerical shear cutting model was developed to predict the cut surface quality. An iterative experimental-numerical approach was employed to model flow and failure behaviour of investigated materials (DC04, X5CrNi18-10, HCT980, HCT600) at various temperatures and strain rates. The mechanical validation of the used failure model was performed with the quasi-static shear cutting experiments done with modified automated punching press by comparing forcedisplacement curves and cut surfaces. Subsequently, the temperature and strain-rate dependent data were integrated into the numerical model and high-speed shear cutting experiments from the previous project were re-simulated. The prediction accuracy of the numerical model in relation to the experimental 95 %-confidence interval was increased from 38 % to 92 % in the second phase.
Publications
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Determination of temperature dependence in Modified-Mohr-Coulomb failure model for process simulation of shear cutting. IOP Conference Series: Materials Science and Engineering, 1238(1), 012028.
Behrens, B.-A.; Brunotte, K.; Wester, H.; Kock, C. & Kildonaviciute, D.
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Extension of the modified Mohr-Coulomb fracture model by a strain rate and temperature dependence. Materials Research Proceedings, 28, 1407-1416. Materials Research Forum LLC.
VASQUEZ RAMIREZ, D.
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Auswirkung von Maschinen- einflüssen auf den Umformprozess/How machinery influences impact the forming process – Impacts of ram displacement in mechanical forming machines on the cutting process. wt Werkstattstechnik online, 114(10), 625-637.
Schmiele, Dennis; Friesen, Dietmar; Krimm, Richard & Behrens, Bernd- Arno
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Vortrag: Numerical analysis of the influence of temperature in shear cutting processes using a stress-based damage model. 15th FTF - Forming Technology Forum. 11.-12.09.2024. Ohlstadt
Wester, H. & Behrens, B.-A.
