Micromechanical model of representative volume of powders material

The paper presents the results of computer simulation and experiments in early stage densification of powder materials representative volume under one-axis compression and the results of powders one side pressing experiments. Representative volume model is 640 spherical particles two deferent diameter (2 mm - 427 pcs; 1.4 mm - 213 pcs) that are thrown by gravity into cubic box with rigid walls. Moving upper wall applies pressure to initial particle packaging. Computer simulations of representative volume were released by using a parallel package LS-DYNA. Experiments were carried out on an droptower impact systems Instron CEAST 9350 in a one-sided pressing mold with an inner diameter of 10 mm. For the experiment, we used powders based on GII-A TU 1916-109-071-2009 graphite, particles less than 315 microns, with the addition of SFP-011A phenol-formaldehyde resin and PMS-1 GOST 4960-2009 copper powder, particles less than 80 microns. Loadind velocity in computer simulation and experiments was 2 m/s. Developed computer model was demonstrated the high stability results for a random change of initial particle packaging. It makes possibility of modeling different loading schemes of representative volume with only one initial particle packaging. The influence internal and external friction on densfication of representative volume was showed a qualitative agreement with the early known data. The model allows realizing a uniform stress state by exclude external friction. The computer model has a good qualitative agreement with the experimental data, and quantitative discrepancies are explained by pleasant assumptions and differences in the initial conditions. Presented micromechanical model of representative volume of powders material can be used in research mechanical behavior powders in early stage densification.