Failure Model for Gear Couplings Under the Criterion of Working Surface Endurance

Abstract

Although it is shown that in some cases the gear couplings durability is significantly less than the turnaround time of a metallurgical unit according to the criterion of teeth contact endurance. As a rule, this leads to unplanned downtime of metallurgical machines and to additional time and financial costs. In order to solve this problem, there is a need for a preliminary assessment of the couplings life before putting them into commercial operation. For this purpose, the article proposes a mathematical model of gear couplings failures according to the fatigue strength criterion. The model is based on the mathematical formalization of the basic concepts of the reliability theory for machine parts, the basic equation for the kinetic concept of structural damage of materials, and the thermodynamic strength condition of solids. In order to implement the created model, the algorithm and the program “The durability” have been developed, which allows evaluating their average design resource under the specified operating conditions. Using the calculation program, theoretical durability studies of the plate feeder coupling were carried out under the operating conditions of the sintering plant. The resource was estimated for two options for calculating contact stresses: using classical methods of the elasticity theory and considering the finite element method of computer-aided design systems. In the first variant, the prediction error was 24%, in the second—9.7%. This indicates a sufficiently high level of the mathematical model reliability and the correct use of the calculation algorithm at the design stage of machines.