Proceedings of the Korean Society for Technology of Plasticity Conference (한국소성가공학회:학술대회논문집)
- 2009.05a
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- Pages.172-175
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- 2009
Prediction of the Forming Limit Diagram for AZ31B Sheet at Elevated Temperatures Considering the Strain-rate Effect
변형률속도 효과를 고려한 AZ31B 판재의 온간 성형한계도 예측
- Published : 2009.05.07
Abstract
The purpose of this study is to predict the forming limit diagram (FLD) of strain-rate sensitive materials on the basis of the Marciniak and Kuczynski (M-K) theory. The strain-rate effect is taken into consideration in such a way that the stress-strain curves for various strain-rates are inputted into the formulation as point data, not as curve-fitted models such as power function. To solve the nonlinear system of equations derived from the equilibrium and constraints in the groove region and the safe zone, the Newton-Raphson method is used. The theoretical FLDs using four different yield criteria, that are von Mises, Hill (1948), Hill (1979), Logan and Hosford, are compared with the experimental, numerical (FEA) and other theoretical results. A new trial is made where a modified M-K model having n-step grooves is introduced to describe a real localized neck.
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