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Fine mesh Analysis of Web Frame in Central Hold, Side Stringers and Transverse Bulkhead Stringers for Suezmax Tanker-166 000 TDW

(A) Objective of the study is fine mesh stress analysis of PROTOTYPE 4 of SUEZMAX tanker under BV requirements. Structural scantlings are given by the Designer (e-mail of 07.02. 2001and e-mail of 16.3.2001 with final documentation) based on BV Rules. Topology and geometry of coarse mesh are based on PROTOTYPE 2 (web frame spacing = 4410 mm) obtained from optimisation process under DnV Rules (cargo density =1.025 t/m3). (B) Global analysis is performed on the 24 web frame spacings long asymmetric model dominating the ship structure scantlings in 3 cargo tanks according to BV Rules for modelling, boundary conditions, loads and safety requirements (faxes of 15.02 and 08.03. 2001). Program MAESTRO is used for analysis. Seven design loadcases are defined according to Designers request based on BV Rules (faxes of 10.01 , 13.02. and 23.02.2001). The Report SPT 2-PROJECT 981 (March 2001) describes global model (Fig. 1) wich provides boundary conditions for fine mesh analysis of middle web frame of central hold and three side and transverse bulkhead stringers at 6700 / 11500 / 17100 mm from BL (Fig. 2). The displacement boundary conditions are automatically transferred from the MAESTRO global model to DSA models. (C) Results of stress analysis are presented for requested parts of structure from the middle of tank 1 to the middle of the model. Maximal BV requirements on bending moments and shear forces are applied in that part. This report covers the results of Detail Stress Analysis. (D) Conclusions: It is obvious that minimal thickness applied in PROTOTYPE 4 are causing excessive stresses in certain locations with respect to BV requirements for fine mesh analysis. Presented DSA analysis, based on requested design loadcases,shows that in all other structural elements BV structural criteria are satisfied.

Suezmax tanker; finite elements; MAESTRO modelling;Detail Stress Analysis

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