Методы прочностных стендовых испытаний моделей и элементов конструкций ракетно-космической техники

The paper considers the methodological support and evaluation of operation reliability of rocket and space equipment using the inlet lips of ramjet engine (RJE) as an example. The successful solution to these issues is largely defined by the optimal selection of materials - special high-temperature alloys and structural ceramics. The methods for modeling the loading conditions of the inlet lips in a high-temperature gas flow are developed from the approaches that ensure the similarity of the external effect on the structural element and equivalency of damage to the material under the model and full-scale conditions. The process of modeling of equivalent states of the material of extreme thermally-loaded zones (models) is realized in the form of specialized procedures on a gas-dynamic test bench to investigate the performance of materials and structural elements in high-temperature gas flows with variable thermo-dynamic parameters. The approaches are based on the classical theories of similarity and different dimensions, which were changed and adapted to investigate the thermal cyclic strength of materials and damageability of structural elements under loading in high-speed high-temperature gas flows. The developed procedures and experimental facilities allowed one to carry out a set of investigations on the functional characteristics, as well as obtain the system of properties for three materials at extremely high temperatures. It is demonstrated that the realized methods provide the required information for the development of structural elements operating under conditions of aerodynamic heating. The results of bench tests are presented in compliance with the data obtained in the numerical analysis of the implemented conditions of thermal loading on a gas-dynamic test bench, as well as the calculations of thermal and stress states of the inlet lips made of various materials. Based on the data of experimental and analytical generalization of the boundary heat-exchange conditions, the numerical modeling of the dependence of TSSS of the models on the geometric parameters and physical properties of the material is performed under test bench conditions. It is implied that such comparative tests should be performed using the models of similar shape and the same geometric dimensions since their difference affects the stress state of structural elements significantly.