Simulation of dynamic stress state of an Aeronautical product structure with random loading
Mathematics. Physics. Mechanics
1. Izhevsk Electromechanical plant "KUPOL", 3, Pesochnaya str., Izhevsk, 426033, Russia
2. Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia
There is the reliable determination of vibrational stresses characteristics in aeronautical product structure during the operation of aviation products along with a plane-carrier topical problem. These characteristics are needed to evaluate the strength and durability performances of the aeronautical product and for an estimation of operating possibility with the more rigid modes of flight. Experimental study of the problem with the use of full-scale prototype or physical models has a significant labour input and cost.
In the present work the technique for numerical simulation and researches results for Aeronautical product random vibrations characteristics calculated by the given technique is presented. For simulation of aeronautical product dynamic stress state the system of solid-state simulation and finite element calculation for complex structure Solid Works is used.
Numerical models and calculated estimation of Aeronautical product random vibration characteristics in the conditions of joint flight with the carrier are presented. The accepted vibrational effect on an aeronautical product corresponds to the real flight loadings and is simulated by the specifying spectral density of accelerations in the knots of a suspension point of an aeronautical product.
Spectral density and variance distribution of stresses in various points of a structure are constructed at structure excitation by random stationary processes. Maximum stresses levels zones for the aeronautical products located on an external suspension bracket of the maneuverable carrier are defined.
To construct random functions, which describe the change of dynamic stresses in time, it is used the statistical modeling algorithms of stochastic processes. Implementations of random functions with the current time value are modeled as the harmonic series with random parameters. Stochastic functions implementations at each current value of the time are modeled in the form of harmonic series with random parameters. The implementations of random processes of stresses, which correspond to dependencies for spectral densities of the stresses, are obtained.
The ordinates of the obtained stress process model have the distribution closer to normal. On the basis of conformity between implementations of processes model and initial spectral density of stresses the levels of stresses are estimated. Random stress processes with the use of standard algorithms of «rainflow» are led to an equivalent set of damaging action of pressure regular cycles. The presented graphs are the probable density of the amplitudes for the resulted regular cycles of stress.
The developed numerical models of the forced random oscillations can be used for an estimation of vibration strength of aviation product under operating conditions.
The work is executed with the RFBR financial support (the project № 13-08-01243-а).
Keywords:aviation product, structure, forced random oscillations, finite element method, dynamic state, vibrational stress, stationary vibration, spectral density, statistical simulation
- Gudkov A.I., Leshakov P.S. Vneshnie nagruzki i prochnost' letatel'nyh apparatov (External loads and strength of aircraft), Moscow. Mashinostroenie, 1968, 470 p.
- Figurovskij V.I. Raschet na prochnost' bespilotnyh letatel'nyh apparatov (Strength calculation for unmanned flight vehicles), Moscow, Mashinostroenie, 1973, 360 p.
- Dimentberg F.M., Kolesnikov K.S. Vibracii v tehnike. Kolebanija mashin, konstrukcij i ih jelementov (Vibration in engineering. Vibrations of machines, structures and their elements), Moscow, Mashinostroenie, 1980, vol. 3, 544 p.
- Zareckij M.V., Sidorenko A.S. Elektronnyi zhurnal “Trudy MAI”, 2011, no 46, available at: http://www.mai.ru/science/trudy/eng/published.php?ID=26006 (accessed 07.07.2011).
- Zareckij M.V., Sidorenko A.S. Elektronnyi zhurnal “Trudy MAI”, 2012, no 58, available at: http://www.mai.ru/science/trudy/eng/published.php?ID=33423 (accessed 26.09.2012).
- Raschety i ispytanija na prochnost'. Metody shematizacii sluchajnyh processov nagruzhenija jelementov mashin i konstrukcij i staticheskogo predstavlenija rezul'tatov, GOST 25.101-83 (Calculations and strength tests. Schematization methods for loading random processes of machine elements and structure, and statistical presentation of the results, State Standart 25.101-83), Moscow, Standarty, 1984, 21 p.