Numerical and experimental research of the stress-strain state of detachable joints of rocket engines
The paper investigates the stress-strain state of critical detachable joints (keyed and threaded) in solid-propellant rocket motors. The purpose of the research is to study the stress-strain state of critical components in rocket technology (using the example of threaded and keyed joints) based on a comparative analysis of the results of numerical modeling in ANSYS and field experiments using photoelasticity. The authors propose a comprehensive approach to ensure high reliability, combining finite element modeling in ANSYS with experimental validation via the photoelastic method. The scientific novelty of the research consists in acquiring more accurate data regarding the stress state of the components under study by introducing a "virtual photoelasticity" algorithm for direct quantitative validation of numerical results. Furthermore, 3D-printing is utilized as an efficient technological tool for the manufacturing of optical models. Critical stress concentrators are identified in thread roots and keyway corners. Results demonstrate high convergence between numerical and physical experiments (the relative error is 0.57 % for the threaded connection and 3.4 % for the keyed connection), confirming the accuracy of the calculation models. The practical significance of the work is that the tested methodology can be used both in the early stages of design and for the strength optimization of the existing structures geometry.