title: A comprehensive study of the delay vector variance method for quantification of nonlinearity in dynamical systems.
abstract: Although vibration monitoring is a popular method to monitor and assess dynamic structures, quantification of linearity or nonlinearity of the dynamic responses remains a challenging problem. We investigate the delay vector variance (DVV) method in this regard in a comprehensive manner to establish the degree to which a change in signal nonlinearity can be related to system nonlinearity and how a change in system parameters affects the nonlinearity in the dynamic response of the system. A wide range of theoretical situations are considered in this regard using a single degree of freedom (SDOF) system to obtain numerical benchmarks. A number of experiments are then carried out using a physical SDOF model in the laboratory. Finally, a composite wind turbine blade is tested for different excitations and the dynamic responses are measured at a number of points to extend the investigation to continuum structures. The dynamic responses were measured using accelerometers, strain gauges and a Laser Doppler vibrometer. This comprehensive study creates a numerical and experimental benchmark for structurally dynamical systems where output-only information is typically available, especially in the context of DVV. The study also allows for comparative analysis between different systems driven by the similar input.
authors.affiliation: Dynamical Systems and Risk Laboratory, Civil and Environmental Engineering , School of Engineering, University College Cork , Cork, Republic of Ireland.
authors.forename: V
authors.identifier: 0000-0002-0178-5546
authors.initials: V
authors.lastname: Jaksic
authors.affiliation: Department of Electrical and Electronic Engineering , Imperial College London , London, UK.
authors.forename: D P
authors.initials: DP
authors.lastname: Mandic
authors.affiliation: Department of Civil, Structural and Environmental Engineering , Trinity College Dublin , Dublin, Republic of Ireland.
authors.forename: K
authors.initials: K
authors.lastname: Ryan
authors.affiliation: Department of Civil, Structural and Environmental Engineering , Trinity College Dublin , Dublin, Republic of Ireland.
authors.forename: B
authors.initials: B
authors.lastname: Basu
authors.affiliation: Dynamical Systems and Risk Laboratory, Civil and Environmental Engineering , School of Engineering, University College Cork , Cork, Republic of Ireland.
authors.forename: V
authors.initials: V
authors.lastname: Pakrashi
keywords: benchmarking; delay vector variance; signal nonlinearity; structural dynamics; wind turbine blade