Study On Structural Optimization Design And Finite Element Analysis Of Trimaran

As a new ship, the special structures of connecting bridge and two side hulls make theloads and structural mechanical characters having great difference between trimaran andconventional ships, three aspects of the hydrodynamic performance, model testing andconceptual design are mainly focused on in recent years. Due to the lack of design andconstruction experience of trimaran, and the few studied of structural optimization design andstrength analysis, the practicable method of trimaran design is not concluded. However, thestructural optimization design and strength assessment are vital to the new ship research anddevelopment. In this paper, taking a warship trimaran as research objects, in the case of thestructure of the preliminary design and the general arrangement had been identified, then thestructural optimization design and strength analysis method were studied together, a structuraldesign scheme of trimaran was proposed based on the background of flourishing trimaran andestablish saving society. A reference for the ship to complete the final design and construction,was provided in thesis, the main contents were as follows,1) The part for design loads and structural strength in the Rules for the Classification ofTrimarans and Provisional Rules for the Classification of Naval Ships from Lloyd’s Registerwas deeply researched, according to the load forecast value from technical specifications andmodel testing, the general and local design load value, strength limited conditions weredetermined for the structural optimization design.2) The Mid-ship section of this trimaran was optimized in different grades, the verticaldistribution of equivalent plate thickness along the profile was given respectively using thetraditional calculation method and the penalty function method for the first gradeoptimization, and the two calculation results were compared. To meet the local strength andstability conditions as standards, the plate thickness, stiffener spacing and properties weredetermine for the second grade optimization. Finally, the structural design and optimizationscheme of trimaran was given in thesis.3) The3D finite element model was built according to the former Optimization Scheme,the typical load cases, boundary conditions and loading simulation methods of structuralstrength assessment were determined, the stress response and its distribution of the structurewas analyzed after the assessment, the rationality of this design of the trimaran was verified, and the design optimization scheme was modified according to the strength assessmentresults, what’s more, the stress concentration of local structure were found at the meantime.4) The place of local structure where features as stress concentration were optimizedfrom its structures and properties. On the basis of the embedded fine meth model, theimprovement situation of stress concentration were compared before and after the structuraloptimization, and the effectiveness of the design optimization scheme to local structure wasverified.