Process modelling for air bending: validation by experiments and simulations

A.H. Streppel; D. Lutters; E. ten Brinke; H.H. Pijlman; H.J.J. Kals

University of Twente in Enschede, Netherlands

In order to be able to evaluate and justify the use of bending simulations in e.g. CAPP applications, the simulations have to be compared to realistic samples from shop floor practice. However, input data concerning e.g. material behaviour, sheet thickness and tool geometry can be controlled in an adequate, reproducible way if obtained under laboratory conditions.
The bending setup leading to the experimental data is elaborated upon. The experiments mainly address the required punch displacement and the sheet length correction, being the main concerns in CAPP applications.
The experiments are employed to evaluate results of simulations of the air bending process. In this case, the results of the equilibrium model, called the ABS-Model (Air Bending Simulation) and a Finite Element Method analysis (both described in an accompanying publication) are involved in the experimental verification.
Diverging trends in the analysis can indicate deficits in the simulations. Presumably, these aberrations can be reflected on the differing assumptions and principles applied in the models or assumptions concerning material behaviour.

Keywords: Bending experiments, Simulations, Verification, FEM, constraints in air bending