Analysis of the mechanical properties model at metal cold separating by shears

Abstract

Borovik P. V. Analysis of the mechanical properties model at metal cold separating by shears. Material working by pressure. 2020. № 1 (50). P. 57-67.

The problem of refining the model of mechanical properties of the material for finite elements simulations is solved in the article. It is allows to tolerance the reliability of mathematical simulation and the accuracy of determining the corresponding energy parameters of cold separation processes of metal by shears. In particular, it is noted that at simulation by the finite element method, using the technique of constructing the stress-strain curves and ductility curve of the material, which get by static tensile tests, the accuracy of the results can be increased. It is indicated that the strain rate in static tensile tests can vary in a wide range and this is due to the value of the engineering strain at fracture. The existence of a functional connection is established and an equation is obtained to determine the strain rate in static tensile tests from the engineering strain at fracture. The application of this equation in the FEM simulation allowed to reduce the relative error to ± 7 %. The conclusion is made that offered method will promote development of mathematical modeling of shearing processes on shears and deepen the understanding of the processes occurring in the metal. In particular, the partial influence of the parameters of mechanical properties model and conditions of processes realization on the results of simulations was studied. The dependences of the ratio of the maximum cutting resistance at different values of the relative shearing velocity, initial yield stress, engineering strain at fracture, the separating section height to the corresponding values of the obtained experimental data were obtained. In general, the simulation results do not contradict the general idea of the metals separation processes in the cold state. The results of the research at making design and technological decisions in the field of cold metal separation by shears can be recommended for use.