Browsing by Author "Filipe, Rodrigo Miguel Carvalho"
Now showing 1 - 1 of 1
Results Per Page
Sort Options
- Structural Design of a Bobsleigh Cowling using FEAPublication . Filipe, Rodrigo Miguel Carvalho; Gamboa, Pedro VieiraThe total mass and natural frequencies are critical factors in bobsleigh design. The ability of the structure to absorb vibrations, achieved in structures with higher natural frequencies, and adjust the bobsleigh’s center of gravity, achieved through reduced total mass, significantly impacts bobsleigh performance. Composite materials, chosen for their high specific strength and ease of manufacturing, are commonly used in the cowling structure of bobsleighs. Correct utilization of these composite materials can minimize total mass, enhancing center of gravity adjustment, and increase natural frequencies, thereby improving bobsleigh performance. This dissertation describes the development of a cowling structure of a bobsleigh with composite materials, using Finite Element Analyses. The motivation for this work lies in the the Portuguese Winter Sports Federation’s aspiration to participate in the 2026 Winter Olympics in the Bobsleigh event, without relying on borrowed bobsleighs. For the development of this dissertation, the structure was based on the outline geometry obtained through CFD analysis and design, divided into two parts: a front part and a rear part. This research endeavors to contribute to the advancement of bobsleigh technology and enhance Portugal’s competitiveness in the Winter Olympics. The development of this dissertation started by investigating the loading conditions to which the structures will be subject to. According to this investigation, the major loading conditions are high accelerations, as a result of the centrifugal forces during high-speed cornering; impact loads, for the cases where the bobsleighs hit the walls of the track; pushing loads, for loads applied by the athletes during the push-off phase in the beginning of the race; and modal analysis, to assess the vibration absorption capacity of the structures. This loads were imported into Ansys, where the bobsleigh structure was tested. Subsequently, the dissertation continued by testing the impact different materials might have on the structure development. With this in mind, five different carbon fibers, four different core materials, and four different manufacturing processes were tested on a preliminary bobsleigh geometry. These results were then compared, considering factors such as the accessibility to these materials and manufacturing processes, and results that may impact the performance: Total Mass and Natural Frequencies. The results that arose from this research proved the material choice is critical for the structural development and allowed us to select the three material combinations most suited to the case at hand. The three material combinations chosen in the previous research were then tested in the final bobsleigh geometry, and compared with the same criteria of accessibility and results that may affect the performance of the bobsleigh. By analyzing this final geometry, it was clear that it presented different structural characteristics when compared to the preliminary one. These analyses on the final geometry yielded a final structure using a combination of M35J carbon fiber, Aramid Honeycomb core, and Infusion manufacturing. To validate these results, an analysis of mesh independence was made. With it, it was possible to conclude that there is convergence of most results. However, for some results, that cannot be said, as there is no clear convergence, being the mesh size and refinement limited by the available computational power. Bearing all the previous conclusions in mind, it was possible to develop a final structure with a mass of 12.3 kg, capable of withstanding all the loads it will be subject to. This structure is presented in detail, with the different laminates used in the different parts and is adjusted just to the current geometry of the bobsleigh, requiring further investigation in case of changes made to the outer geometry of the bobsleigh, as different geometries yield different structural characteristics.