Kinematic Profile Bending with Partial Cross-Sectional Heating

Funding: German Research Foundation (DFG)
Project: 408302329
Contact: Eike Hoffmann M. Sc.

In this project the suitability of partial heating of asymmetric profiles for the reduction of geometrical deviations in bending processes is examined.

In conventional bending of asymmetric profiles a deviation of the shear center position from the bending plane leads to warping in the cross section. To avoid the effect of warping, L-profiles are partially heated through induction and quenched using an air-water mixture after the bending process. Consequently, the position of the stress-free fiber and the position of the shear center changes due to thermal softening in one of the profile areas (see Figure a). For the geometrical result the forming temperature as well as the selection of the heated area is relevant. The first research objective is to find a temperature of the heated area which negates the warping entirely while not influencing the material properties. To quantify the influence of temperature on the stress free fiber, numerical and analytical methods are used (see Figure b).

a) Process principle, b) Analytical and numerical results for stress-free fiber