Structural analysis of main deck of RoPax vessels: A finite element analysis approach combining hull girder loads and local loads for buckling assessment

Abstract

This thesis develops a finite element analysis-based methodology for assessing the buckling behavior of vehicle deck structures in RoPax vessels under combined global and local loading conditions. The proposed approach combines rule-based calculation of hull girder loads, midship section modeling, sub- modeling, and the application of local wheel loads. The methodology is demonstrated on Deck 3 and Deck 5 of a reference RoPax vessel. The global hull girder loads are calculated according to DNV formulations and applied to a finite element model of the midship section. The resulting boundary response is then transferred to refined local deck models, where linear buckling analyses are performed under both pure hull-girder loading and combined hull-girder and wheel loading conditions. The results show that both deck structures maintain sufficient margins against buckling under the investigated design load cases. For Deck 3, the influence of the hull girder load is limited due to its location close to the neutral axis. For Deck 5, the top plate panels are identified as the main buckling-sensitive regions. The local wheel load reduces the buckling load multiplier and shifts the critical deformation towards the loaded areas; however, the structures remain within a safe range.