Diagnostic Inferring on the Bases of Nonlinear Models

Z. Dąbrowski Faculty of Automotive and Construction Machinery Engineering, Warsaw University of Technology, Narbutta 84, 02-524 Warsaw, Poland

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Physical phenomena accompanying destruction processes of technical systems are nonlinear and "low energetic" by nature, while during wearing out mainly a nonlinear disturbance changes. Out of many inference techniques - on the observation basis of the state of the system - the best one is undoubtedly the well defined mathematical model, allowing inferring `backwards' and `forward', which means finding the genesis and prognosis of the phenomenon. However, such model should be nonlinear. Problems related to the identification of nonlinear dynamic models in a frequency domain and a proposition of solving this problem for the needs of technical diagnostics, i.e. in situations when the observed wear out effects are significantly smaller than the dynamic effects - are discussed in the hereby paper. The bases of the proposed method constitute the discussion of possible solutions of a certain class of nonlinear differential equations and resulting from that statements on the possibility of nonlinear disturbance approximations by a series of the selected harmonic frequencies.

DOI: 10.12693/APhysPolA.118.45 PACS numbers: 43.40.Ga, 45.80.+r, 46.40.Ff