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Detailed Program
Paper Number : CO-P01
Time Frame : 12:00~13:30
Presentation Date : Friday, 28, November
Session Name : Computational Ceramic Science and Engineering
Session Chair 1# : -
Session Chair 2# : -
Physical Interpretations of Cap-Related Parameters of the Modified Drucker-Prager Cap Model in Relation to the Deviator Stress Curves of Particulate Materials
Prof. Hyunho Shin
Gangneung-Wonju National University
The physical meanings of cap aspect ratio (R) and transition surface parameter (alpha) of the modified Drucker-Prager cap (MDPC) model in relation to the deviator stress curves of particulate materials generated by the conventional traixial test have been uncovered by simulating the curves using varying R and alpha based on the finite element analysis. The yield surfaces of the model are shown in Figure 1. R controls the rate of the stress rise with the increase of the strain; the smaller the R, the faster the rise of the deviator stress. This phenomenon results because, in J2D1/2 –p space (J2D is the second deviatoric stress invariant and p is the mean stress), the cap with a smaller R needs to move a less distance on the p axis to maintain the current stress state according to the hardening law. As for the influence of alpha, it artificially lowers the true failure surface by the amount that is proportional to alpha so that a fictitious ultimate failure state is achieved. Therefore, it is desirable to set the value of alpha as small as possible unless the numerical analysis using the MDPC model results in a converged solution. An analytical expression to calculate the maximum deviator stress that can be predicted by the MDPC model is provided in terms of alpha and the parameters of the true failure surface.
Acknowledgements : This study was financially supported by the Ministry of Education, Science, and Technology through the National Research Foundation (NRF) of Korea under contract No. 2013R1A1A2007455.