Identification of the Structures Dissipative Properties According to the Experimental Modal Analysis Results

One of the stages of aircraft production is the development of the design dynamic models used to ensure the operating efficiency and the target product lifetime. Initially, such models are based on the technical documentation, and then corrected by the results of the experimental modal analysis of structures. When compiling design models, a priori, mathematical descriptions of elastic, inertial and dissipative properties of structures are used. Descriptions of elastic and inertial forces are based on the concepts of potential and kinetic energies and the positive experience of solving the problems of the dynamical systems eigenmode, but in order to specify the properties of the damping forces, the base is not always available. The article looks at the identification technique of the structures dissipative properties according to the results of modal testing by the phase resonance method. The full-scale dynamic system is described by the mathematical model with the finite number of degrees of freedom. In order to identify the damping forces properties, the ratios between forced monophasic vibrations and structural eigenmodes are used. As an example, a mathematical model of a dynamically similar model of the aircraft is constructed, which describes a number of the structure eigenmodes. A good agreement of the design and experimental amplitude-frequency characteristics of the object is observed. The full-scale aircraft test results, permitting to identify the aircraft dissipative properties are shown.

References

[1] Mezhin V.S., Obukhov V.V. The practice of using modal tests to verify finite element models of rocket and space hardware. Kosmicheskaya tekhnika i tekhnologii [Space engineering and technology], 2014, no. 1 (4), pp. 86-91 (in Russ.).

[2] Druzhinin E.I. Adjustment of analytical models of space structures according to their condition in real conditions. Yubileynaya XV St.-Peterburgskaya mezhdunar. konf. po integrirovannym navigatsionnym sistemam. Sb. tr. [Proc. of 15th St. Petersburg Int. Conf. on Integrated Navigation Systems], St.Petersburg, 2008, pp. 207-208 (in Russ.).

[3] Pisarenko G.S., Matveev V.V., Yakovlev A.P. Metody opredeleniya kharakteristik dempfirovaniya kolebaniy uprugikh sistem [Methods of determining the characteristics of vibration damping in elastic systems]. Kiev, Nauk. Dumka Publ., 1976. 88 p.

[4] Maksimov P.V. About how to specify the dissipative characteristics of dynamic MEMS systems. Nauch. tr. SWorld [Sci. Proc. SWorld], 2012, vol. 3, no. 2, pp. 37-39 (in Russ.).

[5] Varlamov A.V., Grechishnikov V.M., Varlamova N.Kh., Dudin M.P. The model of heterogeneous elastoviscoplastic body in the description of hereditary and dissipative properties Vestnik SamGUPS [Bull. of SamGUPS], 2011, no. 1, pp. 165-169 (in Russ.).

[6] Dmitriev S.N., Khamidullin R.K. Damping matrix correction using experimental modal damping coefficients. Jelektr. nauchno-tekh. izd. "Inzhenernyy zhurnal: nauka i innovacii" [El. Sc.-Tech. Publ. "Eng. J.: Science and Innovation"], 2013, iss. 3. DOI: 10.18698/2308-6033-2013-3-619. Available at: http://engjournal.ru/eng/catalog/machin/rocket/619.html

[7] Klebanov Ya.M., Bruyaka V.A., Vavilov M.A. The determination of the optimum damping characteristics to refine finite element models of the product when modelling vibration tests. Matematicheskoe modelirovanie i kraevye zadachi. Tr. devyatoy Vseross. Nauch. konf. s mezhdunar. uchastiem [Proc. of Ninth All-Russian Sci. Conf. "Mathematical Modeling and Boundary-Value Problems"], Samara, 2013, pp. 90-94 (in Russ.).

[8] Mikishev G.N., Rabinovich B.I. Dinamika tonkostennykh konstruktsiy s otsekami, soderzhashchimi zhidkost’ [Dynamics of thin-walled structures with compartments containing liquid]. Moscow, Mashinostroenie Publ., 1971. 564 p.

[9] Kononenko V.O., Plakhtienko N.P. Metody identifikatsii mekhanicheskikh nelineynykh kolebatel’nykh sistem [Methods of the mechanical nonlinear vibrating systems identification]. Kiev, Nauk. Dumka Publ., 1976. 114 p.

[10] Smyslov V.I. The study of oscillations of a linear system with multipoint excitation, and measurement automation. Tr. TsAGI [Proc. of TsAGI], 1970, iss. 1217, pp. 64-86 (in Russ.).

[11] Clerc D. Methode de recherche des modes propres par calcul de l’excitatiom harmonique optimum d’apres les res les resultats bruts d’essais de vibrations. Note technique: ONERA. 1967, no. 119. 57 p.

[12] Berns V.A. Modal identification of the dynamic systems on the basis of monophasic vibrations. Nauch. vestnik NGTU [Science Bull. of NSTU], 2010, no. 3 (40), pp. 99-109 (in Russ.).