Konstruktion av tältbas för taktält med fokus på vikt och strukturell styvhet

Sammanfattning

This thesis was carried out in collaboration with Thule Group and focuses on the development of a tent base for a roof-mounted tent. The aim of the project was to investigate how the construction and material selection of the tent base could be further developed with focus on weight and structural stiffness. The project was based on the Thule Approach M as a reference product, with the goal of developing a concept that could meet requirements regarding load capacity, robustness and functionality while keeping the weight low. The work started with a pre-study where existing rooftop tents, the reference construction and relevant requirements were analysed. Based on this, a requirement specification was created, including a distributed load of 300 kg, sufficient stiffness, robustness for outdoor use and the possibility to perform FEA simulations. Concept generation was then carried out using functional analysis and brainstorming. The concepts were evaluated using MoSCoW and a Pugh matrix, where the hybrid concept was considered to have the best overall potential and was therefore selected for further development. During the detailed design phase, the concepts were modelled in CAD and analysed using FEA. The simulations were mainly used to compare deformation and stiffness between different geometries. The results showed that the geometry and placement of reinforcements have a clear influence on load distribution, especially in the overhang section of the structure. When additional reinforcement profiles were added, the deformation was reduced, which indicates that the placement of reinforcements has a significant effect on stiffness. The material comparison showed that PET foam is a relevant core material in a sandwich construction, since it can contribute to low weight and good bending stiffness when combined with aluminium sheets. A simplified simulation provided by Thule also indicated that the combination of PET foam and aluminium sheets has potential to withstand high loads. However, the simulation was not based on a verified material model and should therefore only be seen as an indication. The final concept consisted of the hybrid frame structure combined with a sandwich construction using PET foam and aluminium sheets. However, the weight assessment showed that the final concept was not lighter than Thule’s existing solution. This indicates that using a lightweight core material alone is not enough, and that the entire construction needs further improvement. The conclusion is that PET foam and the hybrid structure show potential for further development, but additional simulations, verified material models and practical testing are required before the solution can be considered fully validated.