Whole-body vibration comfort measurement aboard the S. A. Agulhas II and just noticeable difference threshold testing in the laboratory

• Main Author: McMahon, Kim J.
• Other Authors: Bekker, Annie
• Format: Others
• Language: en_ZA
• Published: Stellenbosch : Stellenbosch University 2015
• Subjects: Vibrations > Physiological effect; Structural fatique; Vibration (Marine engineering) > Measurement; Icebreakers (Ships) > Vibration; UCTD
• Online Access: http://hdl.handle.net/10019.1/95938

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.