The Strain Rate Effect on Material Parameters of Porous Bodies during Axial Compression

摘要

The rate sensitivity of powders and porous bodies during uniaxial compression under the room temperature are studied. The special attention is paid to rate dependence of plastic Poisson's ratio. The experimental investigations were carried out for copper based porous blanks. The strain rate and initial porosity effects on plastic Poisson's ratio have been studied. As it was expected the rate dependence of axial stress is confirmed by the most known flow theory for porous bodies. Meanwhile, contrary to Aboaf model and similar ones the strong rate sensitivity of Poisson's ration takes place. To take it into account a new special kind of the constitutive potential has been suggested. Based on micromechanical considerations the new model allows taking into account the rate sensitivity of material functions unlike to Aboaf- Shima model. Obtained results are successfully used to optimize the forging and compaction technology.