Design, Numerical and Experimental Testing of a Flexible Test Bench for High-Speed Impact Shear-Cutting with Linear Motors

Abstract

Given the use of high-strength steels to achieve lightweight construction goals, conventional shear-cutting processes are reaching their limits. Therefore, so-called high-speed impact cutting (HSIC) is used to achieve the required cut surface qualities. A new machine concept consisting of linear motors and an impact mass is presented to investigate HSIC. It allows all relevant parameters to be flexibly adjusted and measured. The design and construction of the test bench, as well as the mechanism for coupling the impact mass, are described. To validate the theoretically determined process speeds, the cutting process was recorded with high-speed cameras, and HSIC with a mild deep-drawing steel sheet was performed. It was discovered that very good cutting edges could be produced, which showed a significantly lower hardening depth than slowly cut reference samples. In addition, HSIC was numerically modelled in LS-DYNA, and the calculated cutting edges were compared with the real ones. With the help of adaptive meshing, a very good agreement for the cutting edges could be achieved. The results show the great potential of using a linear motor in HSIC.

Numerical Investigation of the Damage Effect on the Evolution of Adiabatic Shear Banding and Its Transition to Fracture during High-Speed Blanking of 304 Stainless Steel Sheets

“…Yu and Zhao [23] utilized a modified Brozzo damage model accompanied by effective strain criteria in order to investigate strain and damage evolution during the fine blanking process, while Hambli and Potiron [24] considered the Chaboche-Lemaitre damage law during their study of blanking of 1060 steel sheets, proposing a critical damage parameter of 0.37 instead of 1, which is usually assessed. Finally, a modified nodal release method has been implemented in order to capture the cracking propagation path during FE simulation of high-speed blanking [25], while the GISSMO damage model has also been applied in high-speed impact shear-cutting simulations [26]. Summarizing, Table 1 contains the utilized experimental tools and damage criteria that have been studied during FE simulations in order to investigate the shear localization and the ASB formation during the blanking process.…”