Improvement and validating of numerical models for PTFE powder compaction

Abstract

The proposal of this project is to improve and validate a material model for PTFE powder compaction. This process has high influence on mechanical properties of this material. However, simulating this process is hard. The results must be reproducible due to several loadings and its application points, in a way to represent several industrial cases. Therefore, a procedure involving two kinds of powders (pelleted and not-pelleted) are compacted on a metallic die, having pressure sensors and able to apply digital image correlation technic (DIC), have been proposed. Die makes powder goes through different loading paths in different regions of material under compaction and the validating procedure will be done by a comparison between experimental parameters - reaction force actuator , actuator displacement, pressure on sensors and the results of displacement and strain fields obtained by DIC technic - with the result of finite element simulation. The default Drucker-Prager/Cap model in ABAQUS Software is limited for this application, but it will be improved using subroutines type USDFLD to add hardening on Drucker-Prager surface. Thereby it's expected that model represents better the compaction process of PTFE and de validation procedure demonstrates this improvement. (AU)