Filipkovskii S. Methods and technologies for the design of elastic-damping elements of aerospace engineering

The object of research is the design of aviation and rocket structures with non-linear properties of joints and supports under dynamic loads; the purpose of research is the scientific substantiation and development of a system design methodology for aviation and rocket structures with elastic and damping elements based on nonlinear mathematical models and methods for identifying and eliminating resonant and unstable vibrations under dynamic loads; research methods – simulation of nonlinear oscillations of elements of equipment and aircraft systems by a complex of analytical and numerical methods for analyzing linear and nonlinear systems (Lagrange equations, Galerkin method, nonlinear normal modes of vibration method, decomposition into Taylor and Fourier series, finite element method, continuation method with solutions improvement at each step by Newton's iterative method, numerical integration methods); the results of research – algorithms and application programs packages have been developed to determine the optimal parameters of the elastic-damping suspension on the shock absorbers of the air conditioning unit of the aircraft, as well as to calculate the resonant oscillations of rocket pipelines of various configurations by numerical simulation of oscillations in design cases of dynamic loads; proposed methods and technologies are intended for use in the aerospace industry in solving the problems of detuning from resonant frequencies and protection against overloads; novelty – for the first time, scientifically based methods for designing elastic-damping elements of equipment have been developed, characterized in that their parameters are refined when fine-tuned according to the results of computer simulation of oscillatory processes using nonlinear mathematical models and methods, rather than field tests; for the first time, scientifically based methods for testing calculations of aerospace equipment loaded with the combined effect of internal sources of vibration and oscillations of airframe power elements were developed, and methods were developed for detecting by computer simulation unstable vibration modes, as well as detuning elements with nonlinear structural connections from these modes scientifically based methods for testing calculations of aerospace equipment loaded with the combined effect of internal sources of vibration and oscillations of airframe power elements were developed, and methods were developed for detecting by computer simulation unstable vibration modes, as well as detuning elements with nonlinear structural connections from these modes; for the first time, non-linear mathematical models of aircraft equipment rotors under loads from joint action of unbalance and airframe vibration have been developed, which allowed to determine resonant frequencies and oscillation patterns with loss of stability by numerical experiments, and also showed that detuning from resonances can be performed without changing the design and dimensions by changing the contact angle in ball bearings; for the first time, a non-linear mathematical model of the gas-liquid damper of the fuel line of the liquid rocket has been developed, which allowed calculating the resonant and unstable modes of oscillations of the liquid column in the pipeline; the degree of implementation – the results are implemented at the Antonov Company and Yuzhnoye State Design Office; industry of use – aviation industry, rocket science