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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where a t is the experimentally determined factor of transformation of deformation energy into thermal energy. According to data obtained in special experiments   max , , , t a F e q N   (7) With elastoplastic strains e max at the level of 0.5-1.5% and a loading frequency of up to 50-100 Hz, the temperature rise reached 100-10,000 0 C. This, in turn, increased strains e max and caused an additional rise in temperatures. A new limit state that consists of metal ignition became possible in the oxygen-enriched environment at the operating temperatures that lie in the range t e =600÷800 0 С. It was also important to take into account the effect of hydrogen on the ultimate characteristics of the mechanical properties of materials σ c , e c in expression (3) (Makhutov, 2006; Makhutov, 2008; Makhutov, 2011). In this case, the effect of hydrogen diffusion into the metal and its concentration a H in the studied direction is described by a complex functional dependence:     max ; , , , c H H е F a a F e t N    . (8) The third factor to be taken into account in the analysis of strength and service life was the combination of different frequency modes of cyclic loading when high-frequency low-amplitude cycles from vibrations and pulsations of pressure and temperatures are superimposed on low-frequency high-amplitude cycles of thermomechanical loading. Ensuring strength and service life during testing and operation of liquid-propellant engines should be based on an integrated system of design equations (1) – (8). It can only be achieved through combined application of analytical and numerical methods, organization of the fundamentally new experiments and incorporation of the obtained information into an integrated smart data bank system and a knowledge base that would allow ensuring the operability of units of rocket and space systems in extreme operating conditions (Frolov, 1998; Makhutov, 2008; Makhutov, 2011; Makhutov, 2013; Makhutov, 2017; Makhutov, 2018; Gadenin, 2018; Aliyev, 2018, Deepak Sharma, 2019). The information on the operational loading of the turbines is the initial data for solving this problem (Fig.7).

Fig. 7. Changes in time of operational impacts (pressure p , temperature t , and the number of revolutions of the turbine n ).