Comparison of simulated global stresses with full-scale measurements on an aluminium fast patrol

Paul Klinge, Sakari Rintala, Tuomo Karppinen, Timo Mikkola, Antti Rantanen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific


    Aluminium patrol boats have been designed for operations under severe conditions. The ship hull must withstand high global and local stresses in rough sea conditions and the aluminium structural details must not fail due to fatigue. The speed of the ship and the hull shape may increase the probability of wave impacts and the hydroelastic structural behaviour with which the wave loads exite hull vibration in the lowest eigenfrequency, which considerably increases the number of load cycles. In predictions of wave loads and structural behaviour for design purposes, non-linear wave loads and hydroelastic structural behaviour must be taken into account. The use of traditional linear frequency domain analysis leads to severe underestimation of maximum hull girder stresses, stress ranges and also the number of load cycles. This has been confirmed by global stress measurements during sea-keeping trials. A numerical simulation procedure base on the non-linear strip theory has been developed for time-domain analysis of wave loads and structural response. The procedure takes into account, in an approximate way, non-linear wave loasd due to rarge ship motions. The structural analysis model includes the dynamic structural behaviour. The post-processing of the simulated rasults has been developed for application in structural design work. The calculated results include, for example, prediction of maximum responses and rainflow cycle count processing of stress ranges. The procedure was applied to simulate an aluminium patrol vessel in sea conditions corresponding to the sea-keeping trials. Global stress measurements in sea conditions where wave impacts on the hull occurred frequently. Simulated results were compared to these experimental full-scale results. Theoretical results showed reasonable correlation with experimental data.
    Original languageEnglish
    Title of host publicationHydroelasticity in Marine Technology
    Subtitle of host publicationProceedings of the 2nd International Conference
    EditorsM. Kashiwagi, W. Koterayama, M. Ohkusu
    PublisherYomei Printing Cooperative Society
    ISBN (Print)978-4-87780-001-7
    Publication statusPublished - 1998
    MoE publication typeB3 Non-refereed article in conference proceedings
    Event2nd International Conference on Hydroelasticity in Marine Technology - Fukuoka, Japan
    Duration: 1 Dec 19983 Dec 1998


    Conference2nd International Conference on Hydroelasticity in Marine Technology


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