Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Vibration mitigation for High Speed Craft
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Naval Systems.
2012 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

The crew of small, high-speed marine craft (HSC) is exposed to high levels of vibrations and shocks that can imply risks for adverse health effects. The working environment needs to be improved by appropriately isolating the crew from the severe, non-linear accelerations that characterise the motions of small HSCs. This thesis presents a brief overview of the vibration mitigation techniques flexible hull design, active vibration control and suspension seats. The suspension seat is analysed further. A boat-seat interaction model describing the seat motions when excited by non-linear, vertical accelerations is established. The seat model is used to investigate how the seat characteristics influence the seat response motion, that is, the crew vibration exposure. Published experiment data in terms of accelerations at the seat base measured on a 10 meters HSC unit of the Swedish Coast Guard is used as exciting motion of the seat. By systematically varying the spring stiffness and damping coefficients of the seat, the response motion for 10 different seats are calculated and evaluated according to existing standards regarding whole body vibration exposure, ISO 2631-1 and ISO 2631-5. The thesis concludes that the mitigating effect of the seat can be improved radically by reducing the spring stiffness coefficients and increasing the damping coefficients of the seat. The spring stiffness is however limited downwards by the seat motion stroke, since bottoming out events have to be avoided and the motion stroke for practical reasons cannot be too large. Further, the relation between crew weight and resulting vibration exposure is investigated by varying the crew weight for two different seats. Slightly higher vibration levels are found for the lower crew weigths, although the distinction between the seat reponse motions is small compared to the variations found when comparing different seats. However, it is concluded that the crew weight is an important parameter when studying the vibration exposure, since it influence the motion stroke of the seat.

Place, publisher, year, edition, pages
2012. , 42 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2012:65
National Category
Vehicle Engineering
Identifiers
URN: urn:nbn:se:kth:diva-118798OAI: oai:DiVA.org:kth-118798DiVA: diva2:608438
Subject / course
Naval Systems
Educational program
Master of Science in Engineering - Vehicle Engineering
Uppsok
Technology
Examiners
Available from: 2013-02-27 Created: 2013-02-27 Last updated: 2013-02-27Bibliographically approved

Open Access in DiVA

fulltext(833 kB)1516 downloads
File information
File name FULLTEXT01.pdfFile size 833 kBChecksum SHA-512
2f24600d20921705cd3764a9ce09c16d51e8e749a138be5a121f8b7f4bdcbc5c870e6a07279a162dfde1da36c2fc397e0a7440980f5c509cee89b233c23b9455
Type fulltextMimetype application/pdf

By organisation
Naval Systems
Vehicle Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 1516 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 318 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf