Justification Applicability of the Dynamic Indentation Method for Control Hardness Coating Materials of Elements Liquid Rocket Engines

Abstract

The importance of controlling the mechanical characteristics of coatings of critical products is shown. Calculation formulas for determining the dynamic hardness are given and restrictions for the control of coatings are indicated. The article discusses the features of the dynamic identification method and the substantiation of its applicability to assess the hardness of coating materials for elements of a liquid-propellant rocket engine. Based on the analysis of the mechanics of the contact interaction of a rigid sphere with an elastoplastic two-layer half-space, to assess the dynamic hardness of the coating, it is proposed to use a mixture model, in which the measured hardness is a composite hardness that integrates the hardness of the coating material and the base material to different degrees. According to the research results, a regression dependence in the form of a polynomial of the second degree was obtained, which makes it possible to assess the hardness of a galvanic nickel coating. The accuracy of the regression equation is estimated.