A New spectral method for modeling dynamic ice actions

  • Tuomo Kärnä
  • , Yan Qu
  • , Walter L. Kühnlein

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

42 Citations (Scopus)

Abstract

This paper presents a method of evaluating the response of a vertical offshore structure that is subjected to dynamic ice actions. The model concerns a loading scenario where a uniform ice sheet is drifting and crushing against the structure. Full scale data obtained at the lighthouse Norstro¨msgrund is used in the derivation of a method that applies both to narrow and wide structures. A large amount of events with directly measured local forces was used to derive formulas for spectral density functions of the ice force. A non-dimensional formula that was derived for the autospectrum applies for all ice thicknesses. Coherence functions are used to define the cross-spectra of the local ice forces. The two kind of spectral density functions for local forces can be used to evaluate the spectral density of the total ice force. The method takes account of both the spatial and time correlation between the local forces. Accordingly, the model provides a tool to consider the non-simultaneous characteristics of the local ice pressures while assessing the total ice force. The model can be used in conjunction with general purpose FE programs to evaluate the dynamic response of an offshore structure.
Original languageEnglish
Title of host publication23rd International Conference on Offshore Mechanics and Arctic Engineering
Subtitle of host publicationPipeline Technology
PublisherAmerican Society of Mechanical Engineers (ASME)
Pages953-960
Volume3
ISBN (Print)0-7918-3745-9
DOIs
Publication statusPublished - 2004
MoE publication typeA4 Article in a conference publication
Event23rd International Conference on Offshore Mechanics and Arctic Engineering - Vancouver, Canada
Duration: 20 Jun 200425 Jun 2004

Conference

Conference23rd International Conference on Offshore Mechanics and Arctic Engineering
Country/TerritoryCanada
CityVancouver
Period20/06/0425/06/04

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