Kravtsova Y. Rate dependence of work parameters for deformation process of porous billets in open and closed volumes.

This thesis is directed to perfection of plasticity theory taking into account the rate sensitivity of porous bodies and to development of the calculation method of technological parameters of powder products producing by metal working. The influence of strain rate and strain to the plastic flow of porous bodies during static and dynamic deformation are investigated. For qualitative analysis of rate effect to plastic flow of porous bodies the michromechanical model is developed. The dependences for plastic Poisson's ratio and pressure transmission coefficient are obtained. For quantitative analysis of rate effect the phenomenological analyze is used. To take into account the rate effect the new types of porosity functions are proposed. They contain two new parameters, which is measure of rate sensitivity of porous bodies. On a base of proposed generalized phenomenological model of plasticity theory taking into account the rate sensitivity of porous bodies, the calculation method of technological parameters of the deformation process of porous billets in open and closed volumes is developed. This calculation method is applied in privately owned Ukrainian - Czech enterprise "Ferrite".