Vibration response of the polar supply and research vessel the S. A. Agulhas II in Antarctica and the Southern ocean

[摘要] ENGLISH ABSTRACT: Full scale measurements were conducted on the polar supply and research vesselthe S.A. Agulhas II during a 78 day voyage from Cape Town to Antarctica in2013/2014. Investigations were conducted into the effect of vibration on humancomfort and the structural dynamic response of the vessel. Vibration measuredin the bridge of the vessel is found to have little effect on human comfort for astanding person and is classified as not uncomfortable according to BS ISO 2631-1.Structural fatigue as a result of vibration is found to reach levels where damageis possible in the stern and where damage is probable in the bow during openwater navigation, according to ship vibration guidelines by Germanischer Lloyd.Multivariate statistical analyses are performed to investigate the relationships betweenmultiple predictor variables and vibration response. Factor analysis revealeddata structure from which specific physical phenomena could be identified. Multivariablelinear regression models are developed to predict vibration response andare found to provide more accurate predictions in open water than in ice. The2-node, 3-node and 4-node normal bending modes of the structure are identifiedusing operational modal analysis while the vessel was moored in the harbour. Thenatural frequencies, damping ratios and mode shapes are estimated and comparedusing LMS Operational PolyMAX and ARTeMIS CCSSI. A comparison of operationalmodal analysis results to the STX Finland finite element model show thatthe vessel's modes occur at lower frequencies than numerically predicted. Clearpotential is identified to further investigate structural vibration and operationalmodal analysis algorithm development in future research.

[发布机构] Stellenbosch University