Simulation of amplitude-frequency characteristics of friction strengthening process of flat machine parts’ surfaces

Abstract

Friction treatment refers to surface strengthening (hardening) methods using highly concentrated energy sources, in the process of which a surface hardened layer with a nanocrystalline structure is formed. A highly concentrated energy source is formed in the contact area of the tool-part due to the high-speed friction (60-90 m/s) of the tool on the treatment surface. Friction treatment according to the kinematics of the process is similar to grinding. Transverse grooves are formed on the working surface of the tool to intensify the process of forming a reinforced layer with a nanocrystalline structure. The width of the groove provided a complete escaping of the tool from contact with the treated surface. Additional shock loads occur in the tool-contact area. The friction treatment process is discontinuous. The contact zone on the treated surface receives the pulsed action of thermal energy, shear deformation and additional shock load. The frequency of shock loads depends on the number of grooves on the working part of the tool.The calculation scheme of the elastic system of the machine is developed. A mathematical model to study the dynamic processes that take place during the friction treatment of flat surfaces is built. The amplitude-frequency characteristic of the processing is obtained. The developed model of the machining process based on the analysis of the dynamic characteristics of the process gives the possibility to select the required number of grooves on the working part of the tool, the rotation speed of the tool. The parameters of the elastic system of the machine and the processing parameters at which resonance is possible are determined.