Table of Contents
Journal of Powder Technology
Volume 2014 (2014), Article ID 674782, 9 pages
http://dx.doi.org/10.1155/2014/674782
Research Article

Cumulative Effect of Pressing and Drying on Stress Generation within a Green Ceramic Compact

1Université de Lyon, Institut National des Sciences Appliquées de Lyon, Laboratoire de Mécanique des Contacts et des Structures (LaMCoS), CNRS UMR 5259, Campus de la Doua, bât. Coulomb, 20 Avenue Albert Einstein, 69621 Villeurbanne, France
2Université de Lyon, Université Claude Bernard Lyon 1, Laboratoire d’Automatique et de Génie des Procédés (LAGEP), CNRS, UMR 5007, Campus de la Doua, bât. CPE, 3 rue Victor Grignard, 69616 Villeurbanne, France

Received 14 December 2013; Accepted 29 January 2014; Published 8 April 2014

Academic Editor: Fumio Saito

Copyright © 2014 E. Vidal-Sallé et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The internal stress field induced by uniaxial pressing and subsequent convective drying of a green ceramic powder was simulated by the finite element method. A density dependent elastoplastic constitutive law was used for the mechanical modeling of the compaction. A diffusive water transfer equation and a purely elastic behavior with imposed hydrostrain involving shrinkage were applied for the modeling of the drying process. The key material properties (hydrodiffusivity, hydrocontraction coefficient, Young’s modulus, Poisson’s ratio, and yield surface parameters) had been experimentally measured and introduced as functions of material density and water content. If residual stresses due to the compaction operation were taken into account, the maximum value of the tensile stress at the top external edge of the wheel and at the beginning of the drying process was two times higher than for a stress free green ceramic compact. Beyond the residual stress onset, the compaction operation induced density heterogeneities which had important consequences on the mechanical behavior of the compact.