Authors: Jihoon Hwang Sunchul Choi Seokmoo Hong Naksoo Kim
Publish Date: 2013/07/17
Volume: 27, Issue: 6, Pages: 1815-1824
Abstract
To simulate numerically the material behavior of a ceramic powder feedstock that consist of a twophase mixture of zirconia powder and polymer binder a material model is needed that incorporates the change in volume fraction and temperature dependency of viscosity Heat transfer occurs between the feedstock and the mold during ceramic injection molding CIM The feedstock is heavily influenced by thermal properties such as thermal conductivity and specific heat In this study three models are proposed to explain the material and thermal properties a rigidplastic flow stress model that is dependent on volume fraction and viscosity a thermal conductivity model and a specific heat model as a function of temperature The material parameters in each model are obtained by using the optimization method Error functions are defined as the differences between the experimental measurements and numerical simulation results The parameters are determined by minimizing the error functions The confirmation simulation for each model is conducted by applying cases that are not directly used in the optimization The results of the confirmation simulation tend to follow the experimental results well with correlation coefficients exceeding 092 The numerical simulation of the CIM process with the determined parameters is compared with the flow behavior of an actual CIM process Simulation results such as flow pattern and direction are in good agreement with the measured feedstock behavior Therefore the method for determining the material parameters of the proposed models is feasibleJihoon Hwang received his BS degree from the Department of Mechanical Engineering Sogang University Seoul South Korea in 2011 He will receive his MS degree from the Department of Mechanical Engineering Sogang University Seoul South Korea in 2013 His research interests are twophase flow analysis and computer aided process analysisNaksoo Kim is currently a professor at the Department of Mechanical Engineering Sogang University Seoul South Korea He received his BS and MS degrees from the Department of Mechanical Design Seoul National University Seoul South Korea in 1982 and 1984 respectively He then went on to receive his PhD from UC Berkeley California USA Dr Kim has worked for the Engineering Research Center for Net Shape Manufacturing at Ohio State University as a senior researcher and at Hongik University as an assistant professor Dr Kim’s research interests are metal forming plasticity computer aided process analysis and optimal design
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