A comprehensive study of the delay vector variance method for quantification of nonlinearity in dynamical systems. Issue 1 (January 2016)

• Record Type: Journal Article
• Authors: Jaksic, V.; Mandic, D. P.; Ryan, K.; Basu, B.; Pakrashi, V.
• Is Part Of: Royal Society open science. Volume 3:Issue 1(2016)
• Publication Date: 2016-01
• Subjects: delay vector variance -- signal nonlinearity -- structural dynamics -- benchmarking -- wind turbine blade; Science -- Periodicals; 500
• DOI: 10.1098/rsos.150493
• Languages: English
• ISSNs: 2054-5703

Abstract

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.