Investigation of the Morlet wavelet for nonlinearity detection

Conference · Mon Jan 01 04:00:00 EST 2001

OSTI ID:975825

Robertson, A N ^[1]

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1. Amy N.

Frequency response functions (FRFs), typically calculated by means of the Fourier transform, are used extensively throughout structural dynamics to identify modal characteristics of a structure. Fourier methods work well with linear systems, but have limitations when nonlinearities are present, largely due to their inability to examine nonstationary data. A nonlinear system is often characterized by the variation of its structural response in time. More recently, wavelets have been introduced as an alternative method to FRF calculation. Unlike Fourier methods, wavelets are a time/frequency transform, allowing for the creation of a time-varying FRF. This paper explores the use of wavelet-based FRFs to identify nonlinear behavior in an eight degree-of-freedom spring-mass structure. Examination of temporal changes in the higher frequency range are used to determine the location of the system's nonlinearities.

• Research Organization: Los Alamos National Laboratory
• Sponsoring Organization: DOE
• OSTI ID: 975825
• Report Number(s): LA-UR-01-5818
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
DETECTION
FREQUENCY RANGE
NONLINEAR PROBLEMS
RESPONSE FUNCTIONS