The functional form representation of input-output relationship through Volterra series provides a structured mathematical platform for the study of nonlinear systems. It employs multi-dimensional kernels, which upon convolution with the applied excitation forces, express system response in the form of a power series. Frequency domain transforms of these multi-dimensional kernels provide higher...

Semiannual variation of geomagnetic activity and ap-index in particular is supposed to consist of heliospheric factor (axial hypothesis and Russell-McPherron effect) and magnetospheric/ionospheric factor (equinoctical hypothesis). In our investigation we express ap-index as a magnetospheric response function to solar wind and IMF input. Seasonal variation in ap-index on average (1963– 2003) is ...

Analysis of nonlinear systems has been studied extensively. Based on some recently developed results, a new systematic approach to the analysis of nonlinear Volterra systems in the frequency domain is proposed in this paper, which provides a novel insight into the frequency domain analysis and design of nonlinear systems subject to a general input instead of only specific harmonic inputs using ...

The Frequency Response Function (FRF) of a nonlinear system under white Gaussian ezcitation is computed up to O(P2) in the power spectral density of the input P. The FRF qualitatively shows the ezpected shifts in resonant frequency and supports the observed fact that FRFs from fandam excitation are returned as lkar system FRFs by the Hzlbert transform test.

A nonlinear frequency response based adaptive vibration controller is proposed for a class of nonlinear mechanical systems. In order to obtain the nonlinear Frequency Response Function (FRF), the convergence properties of the system are studied by using the convergence (contraction) theory. If the system under consideration is: 1) convergent, it directly enables to derive a nonlinear FRF for a ...

  ABSTRACT: A prismatic beam made of a behaviorally nonlinear material situated on nonlinear elastic foundation is analyzed under a moving harmonic load moving with a known velocity. The vibration equation of motion    is derived using Hamilton principle and Euler Lagrange equation. The amplitude of vibration, circular frequency, bending moment, stress and deflection of the beam can be calculat...

power transformers are key components in electrical power supplies and their failure could cause severe consequences on continuity of service and also generates substantial costs. identifying problems at an early stage, before catastrophic failure occurs, is a great benefit for reliable operation of power transformers. frequency response analysis (fra) is a new, well-known and powerful diagnost...

Linear system identification of complex nonlinear systems, such as large space structures, can be difficult because such systems are often lightly damped, have dense modal spacing, respond to disturbances over a large frequency bandwidth, and exhibit nonlinear responses. Many excitation signals used to collect frequency response data for linear system identification are poorly suited to systems...

A retinal ganglion cell commonly expresses two spatially overlapping receptive field mechanisms. One is the familiar "center/surround," which sums excitation and inhibition across a region somewhat broader than the ganglion cell's dendritic field. This mechanism responds to a drifting grating by modulating firing at the drift frequency (linear response). Less familiar is the "nonlinear" mechani...