The objective of this thesis is to develop finite element modelling approach for the bonded flooring structure. It shall act as a base for developing design models to study the effects of different structural profiles, materials, and to perform design optimisation. Improvements in the structural design of semi-trailers are needed to cope-up with strict emission regulations, reducing fuel cost and improving payload capacity.
In this study, a finite element modelling approach was developed for bonded flooring structures. Scaled-down models representing different zones of semi-trailer were modelled and simulated for ISO 1496-1 (1990) floor strength and stiffness test. The simulations were validated through experiments performed at the facility of UPM Plywood Oy in Lahti, Finland. Based on the comparative study of finite element simulations and experiment results, critical parameters in the finite element models were investigated. The data acquired from the scaled-down models was used to comprehend the effect of different ply lay-up on the model displacement. Scaled-down models including common structural profiles used in semi-trailers were used to develop a comparative study to comprehend the effect of geometrical profiles on lightweight construction. The scaled-down models were generated with three different spans i.e. 300 mm, 400 mm, and 500 mm. As a result, it was concluded that the I-Profile was a suitable choice for small and medium span whereas Z-Profile was an optimum choice at long span i.e. 500 mm. Scaled-down models with I-profile as a cross member was simulated to understand the application of lightweight materials in design process.
FE modelling approach developed for scaled-down models was applied to the partial (full-width) and full-scale models. These models were then simulated for ISO 1496-1 (1990) floor strength/stiffness and freight load case respectively. Weight reduction of about 5.28% was achieved in the cross members using partial models. Longitudinal beams contributed to more weight reduction. In the ISO 1496-1 (1990) forklift wheel-load case, it was concluded that the preliminary redesign of the flooring structure provides weight reduction of 3.82%. And, it increase in the model stiffness by 2.88% in partial models. Full-scale semi-trailer model with plywood yielded 9.47% less deformations in comparison to chassis-only model for freight load case. Therefore, it was concluded to use plywood panels in the finite element simulations for improved optimisation. The outcome of this thesis would be beneficial for semi-trailer designers in early design process. And, it shall also improve overall design process of the bonded floor semi-trailers
