PSI - Issue 40

N.A. Makhutov et al. / Procedia Structural Integrity 40 (2022) 264–274 Nikolay A.Makhutov at al. / Structural Integrity Procedia 00 (2022) 000 – 000

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For many decades the Mechanical Engineering Research Institute of the Russian Academy of Sciences has been collaborating with leading institutes and specialists from design bureaus of the rocket and space industry in solving these problems. The results of the basic research and applied developments performed in this area are presented in

Makhutov (2011), Makhutov (2013), Makhutov (2019). 2. Analytical studies and standard strength analysis

The creation of liquid-propellant rocket engines (LPE) that use oxygen and hydrogen in the liquid state at cryogenic temperatures as fuel and oxidizer components was a problem of particular scientific novelty and practical importance (Fig. 2). At the first stages of the creation of liquid-propellant rocket engines, the main importance was the validation of strength of their units under extreme influences (pressure p , temperature t , speed v , numbers of revolutions n , numbers of loading cycles N , and operating time τ). In analytical studies of stress -strain states the equations of the theory of bars, plates, shells in linear (elastic) and nonlinear (elastoplastic) formulations were used.     , ( , , , , )( , , ) b t е F p t v n Q M M    . (1) In this case inertial, weight, aerohydrodynamic impacts on the analyzed load-bearing components were reduced to the axial and transverse forces Q, torsion Mt and bending Mb moments that were taken into account in the calculations.

Fig. 2. Oxygen-hydrogen liquid rocket engine RD-120.

Strength analysis carried out for these components is based on nominal and maximum stresses σ n , σ max and strains e n , e max at critical points of dangerous cross- sections, as well as on the fracture stresses σ c and strains е c .

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