PSI - Issue 61

Frank Schweinshaupt et al. / Procedia Structural Integrity 61 (2024) 214–223 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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sufficiently represented by the numerical model setup. The experimentally observed abrupt separation to the end of shearing is due to stored elastic energies in the structure of the fine blanking press and tool, which was verified by means of investigations with a digital contact sensor.

Comparison blanking force progression (a)

Comparison blanking work progression (b)

100 150 200 250 300 350 400

1000 1100 1200 1300 1400

,max (Num) ≈ 2.1%

:Blanking velocity

, (Num) ≈ 3.7%

,max (Exp) ≈ 1.7%

, (Exp) ≈ 8.7%

0 100 200 300 400 500 600 700 800 900

Blanking force / kN

Blanking work / Nm

Numerical

Numerical

,max = ,max ( mm ) ,max ( m m )

, = , ( mm ) , ( m m )

= 15 mm/s = 75 mm/s

= 15 mm/s = 75 mm/s

0 50

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Shearing path / mm

Shearing path

/ mm

Comparison averaged process mechanics (c)

Comparison averaged die roll formation (d)

Max. blanking force ,max / kN 100 200 300 400 500 600 700 800 344.5 0.4 376.9 9.4%

Cumulative blanking work , / Nm 1600 1400 1200 1000 800 600 400 200 Die roll height / mm 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.51 0.015 0.48 5.9% DR1 :Blanking velocity

3.3%

1.3%

1.3%

0.5%

0.6%

1.3%

8%

6.2%

8.9%

8.9%

0.79 0.01 0.80

0.78 0.02 0.77

0.77 0.02 0.77

1315.8 2.1 1272.1

1240.3 1.3 1233.3

1210.6 1.2 1226.4

0.50 0.017 0.46

0.48 0.017 0.45

338.3 0.2

= 45 mm/s 368.5

338.8 0.3

= 75 mm/s 369.3

= 15 mm/s

= 15 mm/s

= 45 mm/s

= 75 mm/s

,max ,

Numerical

DR2

Numerical

Fig. 4: Comparison of blanking force (a) and work (b) progression with averaged maxima (c) as well as averaged die roll height (d)

The numerically calculated maximum blanking forces are about 9% higher than the experimentally determined ones (Fig. 4c), which is due to strength differences between the used flow curve parameters from the database and the experimentally used quenched and tempered steel. The comparison between the experimentally averaged and numerically calculated die roll height shows smaller deviations for the corner areas (DR2) with approx. 1% than for the side areas (DR1) with 6 to 8% (Fig. 4d). However, regarding the meshed element size, the numerical mapping of the die roll is to be evaluated as sufficiently accurate. For numerical analysis regarding the influence of the blanking velocity on the shear zone temperature Z , the area with respect to the center of the defined measuring field was evaluated. Fig. 5a shows the temperature distribution at the highest shear zone temperature that occurred in each case in relation to the shearing path . With increasing blanking velocity, the temperature maximum is shifted towards the separation of the blanked part, which occurs at the top dead center (TDC) with ≈ 5.4 mm (5 mm sheet thickness + 0.3 mm chamfer height + 0.1 mm immersion depth). The temperature distribution reveals a significant increase in shear zone temperature due to increased blanking velocity. In order to quantify the progression of the shear zone temperature as a function of the shearing path, several elements in the area of the die chamfer were averaged in relation to the center of the defined measuring field (Fig. 5b).