Modelling and Simulation the Cracking of Green Metal Powder Body

• Published in: European Congress and Exhibition on Powder Metallurgy. European PM Conference Proceedings pp. 1 - 6
• Main Authors: Jonsén, Pär, Golling, Stefan, Häggblad, Hans-Åke, Gustafsson, Gustaf, Oldenburg, Mats
• Format: Conference Proceeding
• Language: English
• Published: Shrewsbury The European Powder Metallurgy Association 01.01.2016
• Subjects: Compression tests; Computer simulation; Crack initiation; Ejection; Elasticity; Energy; Finite element method; Metal powders; Particle size; Powder compacts; Powder metallurgy; Simulation

During the ejection stage of the powder metallurgy (PM) pressing process the elastic behaviour is important. Especially, if the in the powder compact is unloaded in a non-beneficially manner crack formation can occur. Experiments show a non-linear and also stress dependent elastic behaviour of green bodies. Calibrated against experimental data, a fracture model controlling the stress versus crack-width relationship is used. The softening rate of the fracture model is obtained from the corresponding rate of the dissipated energy. The model is implemented with a smeared crack approach in a finite element code and tested in simulation of a diametral compression testing. Results from simulations correlates well with experimental results. The smeared crack method combined with a cohesive fracture model is an interesting tool for predicting fracture in powder compacts.