Now showing 1 - 2 of 2
  • Publication
    Dynamic response signatures of a scaled model platform for floating wind turbines in an ocean wave basin
    Understanding of dynamic behaviour of offshore wind floating substructures is extremely important in relation to design, operation, maintenance and management of floating wind farms. This paper presents assessment of nonlinear signatures of dynamic responses of a scaled tension leg platform (TLP) in a wave tank exposed to different regular wave conditions and sea states characterised by the Bretschneider, the Pierson-Moskowitz, and the JONSWAP spectra. Dynamic responses of the TLP was monitored at different locations using load cells, camera based motion recognition system, and Laser Doppler Vibrometer. The analysis of variability of the TLP responses and statistical quantification of their linearity or nonlinearity, as non-destructive means of structural monitoring from output only condition, remains a challenging problem. In this study, the Delay Vector Variance (DVV) method is used to statistically study the degree of nonlinearity of measured response signals from TLP. DVV is observed to create a marker estimating the degree to which a change in signal nonlinearity reflects real time behaviour of the structure, and also to establish the sensitivity of the instruments employed to these changes. The findings can be helpful in establishing monitoring strategies and control strategies for undesirable levels or types of dynamic response, and can help better estimating changes in system characteristics over the life-cycle of the structure.
    Scopus© Citations 30  245
  • Publication
    Effect of Road Surface, Vehicle, and Device Characteristics on Energy Harvesting from Bridge–Vehicle Interactions
    Energy harvesting to power sensors for structural health monitoring (SHM) has received huge attention worldwide. A number of practical aspects affecting energy harvesting and the possibility of health monitoring directly from energy harvesters is investigated here. The key idea is the amount of power received from a damaged and an undamaged structure varying and the signature of such variation can be used for SHM. For this study, a damaged bridge and an undamaged bridge are considered with harvesters located at different positions and the power harvested is accessed numerically to determine how energy harvesting can act as a damage detector and monitor. Bridge–vehicle interaction is exploited to harvest energy. For a damaged bridge, a bilinear breathing crack is considered. Variable surface roughness according to ISO 8606:1995(E) is considered such that the real values can be considered in the simulation. The possibility of a drive-by type health monitoring using energy harvesting is highlighted and the effects of road surface on such monitoring are identified. The sensitivity of the harvester health monitoring to locations and extents of crack damage are reported. This study investigates the effects of multiple harvesters and the effects of vehicular parameters on the harvested power. Continuous harvesting over a length of the bridge is considered semianalytically. A comparison among the numerical simulations, detailed finite element analysis, and experimental results emphasizes the feasibility of the proposed method.
    Scopus© Citations 37  566