DEM Research on Stress and Force Chains during Warm Compaction of Intricate Parts

A Discrete Element Method (DEM) was applied to establish a model that simulates a cross-shaped powder system under hot compaction. The average stress, force chains, principal stress angles, and coordination numbers were recorded and studied. The experimental results show that the stresses in the vertical part of the cross-shaped powder system are higher than in the lateral part, and the highest stress value is always concentrated in the upper zone of the system. This is also consistent with the strength of the force chains in the vertical part being stronger than that in the lateral part. The angle of the principal stress is consistent with the direction of the external load and shows anisotropy and irregular distribution during the compaction process. The vertical section of the cross-shaped powder system tends to be 90°, except for the area close to the lateral section, which tends to be 70°. However, the principal stress angle of the lateral part tends to be 0° during the compaction process. The coordination numbers of the measurement circles have a series of sudden changes and increase with the pressing, the changes of which correspond to the stress distribution.