TY - BOOK
T1 - A comparison between optimisation algorithms for metal forming processes
T2 - With application to forging
AU - Bonte, M.H.A.
N1 - This report is the result of an internship of the author at the Ecole Nationale Sup¶erieure des
Mines de Paris (ENSMP), department Centre de Mise en Forme des Mat¶eriaux (CEMEF)
in Sophia-Antipolis, France. The author is employed as a PhD student at the University
of Twente (UT) in Enschede, The Netherlands. The internship was performed from May
to August 2005. Its aim was to compare two di®erent optimisation algorithms for metal
forming processes, which are being developed at CEMEF and the UT, and to learn from
each other during the cooperation. This report describes the results.
PY - 2005
Y1 - 2005
N2 - During the last decades, Finite Element (FEM) simulations of metal forming processes have
become important tools for designing feasible production processes. In more recent years,
several authors recognised the potential of coupling FEM simulations to mathematical opti-
misation algorithms to design optimal metal forming processes instead of only feasible ones.
The aim of this report is to compare two potentially powerful optimisation algorithms for
optimising metal forming processes to each other: the Metamodel Assisted Evolutionary
Strategy (MAES) developed at CEMEF and the Sequential Approximate Optimisation
(SAO) algorithm developed at the University of Twente.
For SAO, special attention was given to sequential improvement strategies. Four strategies
have been developed, implemented and investigated:
1. SAO without zooming (SAO)
2. SAO with Zooming and Resampling (Z+R)
3. SAO with improvement by Minimising a Merit Function (SAO-MMF)
4. SAO with improvement by Maximising Expected Improvement (SAO-MEI)
(Z+R) gave bad results for analytical test functions and was excluded from further research.
SAO, SAO-MMF and SAO-MEI were compared to MAES by applying them to two forging
processes: the Triaxe and the Engrenage. Next to the three SAO variants and MAES, an
iterative BFGS algorithm and reference situations were also taken into account in the
comparison. It can be concluded that:
² All optimisation algorithms yield better results than the reference situations
² SAO and MAES both outperform the iterative BFGS algorithm
² SAO-MMF and SAO-MEI yield better results than SAO without zooming
² SAO-MMF, SAO-MEI and MAES perform comparably well for both forging applica-
tions. Although the di®erences are negligible, SAO-MEI proved to be slightly more
superior than the other two algorithms for both the Triaxe and the Engrenage
AB - During the last decades, Finite Element (FEM) simulations of metal forming processes have
become important tools for designing feasible production processes. In more recent years,
several authors recognised the potential of coupling FEM simulations to mathematical opti-
misation algorithms to design optimal metal forming processes instead of only feasible ones.
The aim of this report is to compare two potentially powerful optimisation algorithms for
optimising metal forming processes to each other: the Metamodel Assisted Evolutionary
Strategy (MAES) developed at CEMEF and the Sequential Approximate Optimisation
(SAO) algorithm developed at the University of Twente.
For SAO, special attention was given to sequential improvement strategies. Four strategies
have been developed, implemented and investigated:
1. SAO without zooming (SAO)
2. SAO with Zooming and Resampling (Z+R)
3. SAO with improvement by Minimising a Merit Function (SAO-MMF)
4. SAO with improvement by Maximising Expected Improvement (SAO-MEI)
(Z+R) gave bad results for analytical test functions and was excluded from further research.
SAO, SAO-MMF and SAO-MEI were compared to MAES by applying them to two forging
processes: the Triaxe and the Engrenage. Next to the three SAO variants and MAES, an
iterative BFGS algorithm and reference situations were also taken into account in the
comparison. It can be concluded that:
² All optimisation algorithms yield better results than the reference situations
² SAO and MAES both outperform the iterative BFGS algorithm
² SAO-MMF and SAO-MEI yield better results than SAO without zooming
² SAO-MMF, SAO-MEI and MAES perform comparably well for both forging applica-
tions. Although the di®erences are negligible, SAO-MEI proved to be slightly more
superior than the other two algorithms for both the Triaxe and the Engrenage
KW - IR-59537
M3 - Report
BT - A comparison between optimisation algorithms for metal forming processes
PB - University of Twente
ER -