Identification of the Structures Dissipative Properties According to the Experimental Modal Analysis Results
Authors: Berns V.A., Zhukov E.P., Marinin D.A. | Published: 11.08.2016 |
Published in issue: #4(109)/2016 | |
Category: Aviation and Rocket-Space Engineering | Chapter: Aircrafts Development, Design and Manufacture | |
Keywords: mathematical model of structure, identification of mathematical model, experimental modal analysis, eigenmodes, monophasic vibrations, damping matrix |
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.
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