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The green compact of uniform density is a fundamental requirement for the production of a good quality and high strength part. Density inhomogeneity can be caused by friction force owing to interparticle movement and relative slip between the powder particles and the die wall. Also, the die geometry and the sequence of punch movements results in a lack of density homogeneity for a compact of complex shape. In this study the mechanical behavior of alumina ceramic powder during maximum applied stress stage to the unloading and after the ejection are analyzed using Finite Element Methods, in which the powder is modeled as an elastic-plastic continuum material. The modify Drucker-Prager Cap model was chosen as the yield surface of the medium, the surface consists of a linear shear failure, transition, and elliptic cap surface. The elastic properties and plastic parameters of the model were expressed as a function of density, from which realistic powder properties are generated and fed into ABAQUS finite element code; and the constitutive modeling of the frictional behavior of the powder in the die is modeled by Coulomb's friction low.
About the author
Omed Gh. Abdullah, is an assistant professor of materials science in physics department, college of Science, University of Sulaimani, Kurdistan Region-Iraq. His main research interests include fabrication and characterization of advanced materials, polymer nanocomposites, as well as simulation of powder compaction.
