77 research outputs found

    Evaluation of output frequency responses of nonlinear systems under multiple inputs

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    In this paper, a new method for evaluating output frequency responses of nonlinear systems under multiple inputs, defined as a sum of sinusoids of different frequencies, is developed. The method circumvents difficulties associated with the existing “frequency-mix vector” based approaches and can easily be applied to investigate nonlinear behaviors of practical systems, including electronic circuits, at the system simulation and design stages. Application of the method to the analysis of nonlinear interference and distortion effects in communication receivers is studied, and specific procedures are proposed which can be directly used in practice for this analysi

    A novel approach for nonlinearity detection in vibrating systems

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    This paper proposes a novel approach for nonlinearity detection in vibrating systems. The approach is developed based on a new concept recently proposed by the author known as nonlinear output frequency response functions (NOFRFs) and the properties of the NOFRFs for nonlinear systems with multiple degrees of freedom (mdof). The results of numerical simulation studies verify the effectiveness of the approach. Nonlinear components often represent faults in practical mdof systems including beams. The proposed approach therefore has significant potential in the fault diagnosis of practical mdof engineering systems and structures

    Linear parameter estimation for multi-degree-of-freedom nonlinear systems using nonlinear output frequency-response functions

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    The Volterra series approach has been widely used for the analysis of nonlinear systems. Based on the Volterra series, a novel concept named Nonlinear Output Frequency Response Functions (NOFRFs) was proposed by the authors. This concept can be considered as an alternative extension of the classical frequency response function for linear systems to the nonlinear case. In this study, based on the NOFRFs, a novel algorithm is developed to estimate the linear stiffness and damping parameters of multi-degree-of-freedom (MDOF) nonlinear systems. The validity of this NOFRF based parameter estimation algorithm is demonstrated by numerical studies

    An algorithm for determining the output frequency range of Volterra models with multiple inputs

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    A new algorithm for determining the output frequency range and the frequency components of Volterra models under multiple inputs is introduced for nonlinear system analysis. For a given Volterra model, the output frequency components corresponding to a multi-tone input can easily be calculated using the new algorithm
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