| Résumé | This report presents results of a finite element analysis of ship frames subject to ice loads. The analysis covers the full range of frame behavior, from elastic, through yield, through the formation of initial mechanisms, through large deformations. The behaviors often include some local instabilities (buckling). The analyses continue until the total central deformation reaches about 10% of the frame span. The parameters include: · frame profile: Angle, Tee, Flat · frame span: · load length: patch (trans.), uniform (long-l) · web thickness: · flange thickness: · end brackets: with, without. The ANSYS finite element program was used in this study [1]. The aim of the study is to determine the validity of the limit state equation employed in the IACS new Unified Requirements for Polar Ships [2]. In particular, the study focuses on the reasons why some frames may not behave in accordance with the limit state equations, with local buckling and tripping as key issues. The report builds upon the work presented in [3]. In the present draft of the UR, there are no explicit tripping requirements. There are local buckling requirements, though they are essentially the same local buckling requirements employed widely in classification requirements for open water ships. This report examines the possible need for tripping requirements in the Polar Rules and the possible need for changes to the local bucking requirements. |
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