Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: A continuous comfort analysis of the whole-body vibration level aboard the S.A. Agulhas II during the 2013-2014 Antarctic voyage was conducted ac- cording BS ISO 2631-1:1997, assuming a standing posture. Just noticeable difference in magnitude testing was conducted on nine subject in the standing posture on a man-rated shaker in the laboratory environment. Two stimuli, a 5 Hz sinusoidal stimulus with a magnitude of 0,5 m.s-2 and a slamming event recoded during the voyage with a magnitude of 0,2 m.s-2 where selected as the stimuli on which to investigate the just noticeable difference thresh-old. The study shows that the vibration level for the duration of the voyage can be considered to be not uncomfortable. The results of the just notice-able difference threshold obtained for the sinusoidal stimulus concur with that found in literature for seated subjects. The just noticeable difference threshold obtained for the ship stimulus does not correlate with the results for the sinu-soidal vibration, implying that there may be an error in the vertical weighting filter provided by the standard or that Webers law does not hold for the just noticeable difference threshold of standing subjects. / AFRIKAANSE OPSOMMING: 'n Deurloopnede gemakanalise van volliggaam vibrasievlakke aanboord die S.A. Agulhas II is uitgevoer. Die analise tydens die 2013-2014 Antarktiese reis is gedoen volgens BS ISO 2631-1 : 1997 vir 'n staande postuur. 'n Net-opmerkbare-verskildrempel toets is uitgevoer op nege vrywillers in 'n staande postuur deur vibrasieherkonstruksie op 'n platform in die laboratorium. Twee stumuli, 'n 5 Hz sinusvorminge stimulus (0,5 m.s-2 r.m.s.) en 'n branderim-pak stimulus (wat tydens die reis opgeneem is, 0,2 m.s-2 r.m.s. is gebruik) om die net-opmerkbare-verskildrempel to ondersoek. Die studie toon dat die vibrasievlakke gedeurende die reis as `nie ongemaklik' geklassifiseer kan word. Die resulte van die net-opmerkbare-verskildrempel verkry vir die sinusvormige stimulus stem saam met bevindinge vir sittende vrywilligers uit die literatuur. Die net-opmerkbare-verskildrempel verkry vir die skip stimulus stem egter nie 'n moonlike onakkuraatheid weegfunksie is wat deur die standard is aanbeveel word of datWeber se wet nie toepaslik is vir die net-opmerkbare-verskildrempel van staande vreywilligers nie.

Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: Full scale measurements were conducted on the polar supply and research vessel the S.A. Agulhas II during a 78 day voyage from Cape Town to Antarctica in 2013/2014. Investigations were conducted into the effect of vibration on human comfort and the structural dynamic response of the vessel. Vibration measured in the bridge of the vessel is found to have little effect on human comfort for a standing 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 damage is possible in the stern and where damage is probable in the bow during open water navigation, according to ship vibration guidelines by Germanischer Lloyd. Multivariate statistical analyses are performed to investigate the relationships between multiple predictor variables and vibration response. Factor analysis revealed data structure from which specific physical phenomena could be identified. Multivariable linear regression models are developed to predict vibration response and are found to provide more accurate predictions in open water than in ice. The 2-node, 3-node and 4-node normal bending modes of the structure are identified using operational modal analysis while the vessel was moored in the harbour. The natural frequencies, damping ratios and mode shapes are estimated and compared using LMS Operational PolyMAX and ARTeMIS CCSSI. A comparison of operational modal analysis results to the STX Finland finite element model show that the vessel’s modes occur at lower frequencies than numerically predicted. Clear potential is identified to further investigate structural vibration and operational modal analysis algorithm development in future research. / AFRIKAANSE OPSOMMING: Volskaal metings was op die poolvoorsienings en navorsingskip die S.A. Agulhas II uitgevoer tydens ’n 78 dae reis van Kaapstad tot Antarktika in 2013/2014. Ondersoeke is uitgevoer met betrekking tot die effek van vibrasie op menslike gemak en die strukturele dinamiese reaksie van die vaartuig. Vibrasie wat in die brug van die skip gemeet is, het min invloed op menslike gemak vir ’n staande persoon en word geklassifiseer as nie ongemaklik volgens BS ISO 2631-1. Strukturele vermoeidheid as gevolg van vibrasie bereik vlakke waar skade moontlik is in die spieël en waar skade waarskynlik is in die boog tydens navigasie in oop water, volgens skip vibrasie riglyne deur Germanischer Lloyd. Meerveranderlike statistiese ontledings is uitgevoer om die verhoudings tussen verskeie voorspellerveranderlikes en vibrasieterugvoer te ondersoek. Faktorontleding het data struktuur openbaar waaruit spesifieke fisiese verskynsels geïdentifiseer kan word. Multi-veranderlike lineêre regressiemodelle was ontwikkel om vibrasie reaksie te voorspel en lewer meer akkurate voorspellings in oop water as in ys. Die 2-nodus, 3-nodus en 4-nodus normale buig modes van die struktuur is geïdentifiseer met behulp van operasionele modale analise terwyl die skip vasgemeer in die hawe is. Die natuurlike frekwensie, demping verhoudings en mode vorms is beraam en vergelyk met behulp van LMS operasionele Polymax en ARTeMIS CCSSI. ’n vergelyking van operasionele modale analise resultate en ’n STX Finland eindige element model toon dat die vaartuig se modusse voorkom by laer frekwensies as wat numeries voorspel word. Duidelike potensiaal is geïdentifiseer om strukturele vibrasie en die ontwikkeling van operasionele modale analise algoritmes te ondersoek in toekomstige navorsing.