Development of Simulation Method for Predicting Compact Shape in HIP and CIP

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The main objiective of this study is to develop simulating methods to predict the shape of compacts and sensity distribution in the compacts in isostatic pressing of powders. For HIP, a visco-plastic finite element method was developed, whereas for cip a formulation was developed for rigid-plastic finite element analysis; an attempt was also made to analyze by an elastoplastic finite element method.The conventional vonstitutive equation appeared not to apply to alumina powders tested. A new constitutive equation was therefore presented. Further, a non-associated flow rule was also proposed, since the deformation of the ceramic powders is attributed to the relative sliding between particles, which means that internal friction exists.The rigid-plastic finite formulation was developed based on the newly developed constitutive equations, and the results were compared with experimental ones. It appeared that the non-associated flow rule provided better agreement with that of expermental compared with the associated one. Howeber, the non-associated flow rule should be investigated further.An attempt was also made to examine the constitutive equation by the three-dimensional compaction. Also a plane-strain compacting device on which stress ration can be varied during a compacting process was newly designed and built. It was thus found that anisotyopy was apparently induced in the powder during compaction, althoug the constitutive equations, both conventional and newly developed, are isotropic.Generalization of the constitutive equations including anisotropy is a further woek and a systematic study of the mechanics of granular matreials will be pursued.