MODELING THE PROCESS OF CONTACT INTERACTION OF A TOOL WITH A PART WITH A SUPPLEMENT OF AXIAL ULTRASONIC OSCILLATIONS

Abstract

The process of ultrasonic extrusion of rubber with superposition of ultrasonic vibrations is investigated and modeled. Based on the rheological model of deformation of an ideal elastic-plastic body, dependences have been developed for calculating contact pressures and specific friction. When conducting this study in order to simplify the mathematical model, the assumption was made that the phenomenon of surface hardening has little effect on the magnitude of the contact pressure and the friction force during plastic deformation. This mathematical model describes the complex movement of a tool (rotational and oscillatory movement of a tap). The system of obtained dependences, which describes the influence of the amplitude of oscillations, the direction of oscillations, the strain rate, and the mechanical properties of the processed material on the value of the contact pressure, allows one to calculate the parameters of the plastic deformation process with the application of ultrasound. Thanks to this description, it is possible to obtain the value of contact pressure and friction forces for each section of the load diagram. When analyzing the results, it was found that with an increase in the amplitude of the oscillations, the contact time of the tool with the machined surface decreases, therefore, the contact pressure, the specific friction of axial and torsional vibrations during the period, respectively, decrease within the limits of the studied factors. The obtained dependence for determining the diameter of the hole when extruding the rubber with superposition of axial vibrations, taking into account the elastic properties of the workpiece material. These dependences make it possible to determine the diameter of the hole and the tolerance for its manufacture, depending on the size and design of the tap, the size of the rubber, the mechanical properties of the workpiece material, processing conditions and the magnitude of ultrasonic vibrations. The advantage of this study is a detailed analysis of the contact interaction of the tool with the part and taking into account the mechanical properties of the processed material, which allows you to select processing modes and ensure maximum performance.