Structural Analysis of Polar Icebreaker Bows.

• Main Authors: Fey, Edgar, Pilkey, Walter, Estes, Phillip
• Other Authors: IIT RESEARCH INST CHICAGO IL
• Format: Text
• Language: English
• Published: 1968
• Subjects: Marine Engineering; *ICEBREAKERS; STRUCTURAL PROPERTIES; COAST GUARD; COMPUTERS; COMPUTER PROGRAMS; MATHEMATICAL MODELS; GEOMETRIC FORMS; MATRICES(MATHEMATICS); BOUNDARY VALUE PROBLEMS; TRANSFORMATIONS(MATHEMATICS); SHIP MODELS; BENDING; STRESSES; STRAIN(MECHANICS); SHIP HULLS; SUBROUTINES; BEAMS(STRUCTURAL); PANELS; LOADS(FORCES); ICE; KINETIC ENERGY; DEFORMATION; FORCE(MECHANICS); SUPPORTS; SHIP BOWS; Psi; Icebreaker
• Online Access: http://www.dtic.mil/docs/citations/AD0843248; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0843248

An icebreaker bow structure was analyzed by the finite element method using the SAMIS structural analysis and matrix interpretive system. Several structural modeling techniques were investigated and a combined model using a detailed stiffened plate representation in the primary area of interest and an orthotropic plate representation elsewhere was found to provide adequate structural detail and at the same time account for the complex geometry of the problem in a satisfactory manner. The structural analysis of a structure as geometrically complex as an icebreaker bow does not appear practical without some form of automatic data preparation. A special purpose computer program which calculates the required geometric parameters of a ship structure and automatically carries out most of the data preprocessing functions required for input to the SAMIS system was developed. Complete source program listings and instructions are presented. A review of available literature on icebreaker bow loadings and failure histories indicated that the most damaging loads on previous icebreakers apparently did not come from dead ahead ramming, but from inadvertent side collisions with ice, involving sides of the bow somewhat aft of the stem. The size of the loaded area in such cases is quite uncertain as it depends to a large extent on the geometry of the ice contacted. Accordingly the demonstration problems in this study were concerned with a region of the bow of a Westwind class ship where a high failure incidence was reported and variation in the size of the loaded area. The yield pressures were found to be quite low, varying from 488 to 99 psi as the loaded area varied from 32 by 32 in. to 96 by 192 in.