engleski

Racking analysis of car carrier -5400 cars

Faculty of Mech. Eng. and Naval Arch. and Uljanik Shipyard have performed 3D FEM analysis of Yard 441-442 using MAESTRO software available at University of Zagreb. The coarse-mesh, full-asymmetric, global car carrier FE model was developed (Pt B,Ch 7, App 2). It simultaneously provides all needed data for the (1) longitudinal strength analysis and (2) racking analysis of three watertight bulkheads (Fr 51 / M / 147) caused by the transverse racking induced forces. Full ship 3D FEM model has 35 983 DOF and 20 690 macroelements (10 527 stiffened panels and 7 343 beams). Both analysis were reported in Report no. ULJ441/1 PRELIMINARY This Report suplements results for racking analysis by using horizontal accelerations requested by RINA in fax of 24.08.2001 Loading condition 5 (Cars on decks 1 to 11, arrival) was adjusted to R.I.N.A requirements for racking (Pt B, Ch 5, Sections 3-6 and Pt B, Ch 7, Appendix 2. Maestro loadcases 1 and 2 (corresponding to heel to STB and PS), are prepared. All masses (light ship, cars,etc.) were given corresponding accelerations based on the acceleration vector components calculated from the Rules (Pt B, Ch 5, Section 3). They are applied for ship draft of 7.4 m in loading condition 5. Car masses were concentrated in mesh nodes of the corresponding decks or distributed on hoistable decks according to the force plan supplied by the Yard. Pressures are calculated according to RINA requested distributions. Stress levels were adjusted to R.I.N.A Rules (Pt B, Ch 7, Section 4). Ship satisfies R.I.N.A. requirements. Comments are given for areas of higher stress or lover safety with respect to Maestro collapse and serviceability criteria adjusted to RINA safety factors. At Fr. M the thickness of plating of regions around doors in bulkhead and the thickness of frame web between D6 and D8 were increased based on obtained results and Designers request. At Fr. 51 the thickness of the plating right of the door to CL between D5 and D6 was increased, also as result of obtained analysis and Designers request.

car carrier; finite elements; MAESTRO modeling; racking analysis

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