innovative fe-analysis of the roller burnishing process for different ...

F. Klocke, V. Bäcker, H. Wegner and A. Timmer.
In order to provide a quantitative comparison of the simulated and experimental results,
this evaluation methodology was applied. The results of this comparison are shown
exemplarily for the roller burnishing of Ti-6Al-4V (Figure 3). They achieve generally a very
good correlation between calculated and measured results for all geometries.
The distribution of the residual stresses for thin walled geometries differs significantly
from the stress distribution observed and calculated for plane geometry, which is affected
only in the rime zone of the processed surface. Thin walled geometries are influenced over
their complete thickness. Due to the roller burnishing process, negative residual stresses are
induced in the rime zone. These stresses are compensated by positive residual stresses in the
inner part of the workpiece.
The contour plot of the residual stress in the simulation using curved geometry shows that
the roller burnishing process does not induce stresses only in the processed curved zone. The
stress induction is extended to the adjacent plane areas.
4 CONCLUSIONS
The high stress gradients in the rime zone after roller burnishing require fine meshing of
this area, which limits the model size and renders a macro-modelling of the roller burnishing
process as time-inefficient or even impossible. The model simplifications and the assumptions
made in the modelling phase cause additional scatter to the numerical errors and have to be
chosen carefully. A quantitative prediction of the residual stress state of the rime zone
requires a sophisticated and representative validation strategy based on statistically firm
evaluation of the model results, which is what these FE-models achieve. All developed FEmodels
were validated and are able to predict the residual stress state after roller burnishing
with sufficient accuracy.
5 AKNOWLEDGEMENT
The authors gratefully acknowledge the financial support from the European 6th
Framework Programme through the research project VERDI (Virtual Engineering for Robust
Manufacturing with Design Integration; http://www.verdi-fp6.org).
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