Modeling quality criteria for restoring parts of cars, vehicles and road-building machines

Abstract

The article analyzes the types, methods and techniques of parts processing at restoration and quality criteria of parts of cars, other vehicles and road-building machines in terms of efficiency. Correlations between the quality criteria and the functionality of the part have been established, for which the requirements for machine safety and reliability after the restoration of individual parts have been taken. A mathematical model has been developed in the form of an algorithm for selecting the best variant of the restoration technology for a functionally important part, based on a typical restoration technological process, which consists in the development of a multi-criteria problem, the initial postulates of which are matrices: W “wear resistance → durability”; S “safety → reliability”; F “part fragility → machine safety”. New parameters in the form of coefficients describing roughness, hardness and riveting of a part have been proposed. In particular, the authors define the coefficient of technological isotropy of roughness, which evaluates the roughness parameters in the process of technological changes of a part; the coefficient of isotropy of hardness, which compares the hardness parameters on the surface of the part and in the core of it; the coefficient of intensity of hardness, which is a complex parameter and in which there is a change of hardness by the depth of the part and the value of hardness depth (riveting). The purpose of introducing these coefficients is consistent with the model being developed to select the optimal technology for restoring parts of cars, other vehicles and road-building machines.