| dc.description.abstract | This bachelor thesis is written in collaboration with the student organization UiS Aerospace, focusing on the production of the rocket fuselage for the Borealis program. The optimal production method was determined to be a combination of glass fiber and filament winding, which became the central focus of this thesis. The combination provides exceptional weight-to-strength ratio, and the ability to transmit and receive electronic signals.
In order to produce the glass fiber fuselage, a cylindrical mandrel was required. The mandrel was designed and manufactured in-house. Once mounted on the winding machine, the mandrel undergoes rotation around its central axis, subjected to a pull force estimated at 30kg, in addition to its specific weight. The main design consideration revolves around deformation, with a maximum allowable limit set at 2-3mm deformation. To predict the deformation, a simulation was conducted using Ansys. The resulting deformation was found to be 0.88mm, which was within the acceptable range for mandrel production.
The optimal fiber angle for the anisotropic glass fiber was assessed through a structural analysis using classical lamination theory. Where the structural analysis was specifically designed against the predicted dynamic pressure, calculated using OpenRocket and Python simulations. This resulted in a graph showing that the optimal fiber angle is close to 90 degrees. This graph was compared with the manufacturing parameters, and the desired angle was found determined to be 70 degrees through the use of CADWIND. This orientation was further used in a Tsai-Wu Analysis, using Ansys, where the moment with the most dynamic pressure was used. The resulting Failure Index amounted to $FI = 0.019$, where $FI \geq 1$ defines failure. This indicated that the structural integrity of the fuselage will uphold.
Before conducting the filament winding process, some of the winding parameters were changed, resulting in a change in the fiber angle from 70 to 81 degrees. Based on the earlier simulations,it was concluded that this angle is closer to optimal, yielding a lower $FI$ and a higher factor of safety.
The launch of Borealis II took place at Helleland Spaceport, UiS Aerospace's private launch site, on April 27th. Despite a misfire and necessary rewiring of the launch mechanism, Borealis II successfully launched, reaching an altitude of 2100 meters and a maximum velocity of 950 km/h. The parachute deployed at apogee instead of the intended 1 km height, resulting in a spike in acceleration and the loss of the aft airframe due to undersized screws. Nevertheless, the fuselage performed admirably, enduring dynamic pressure, meeting all product specifications and carrying the avionics to a safe landing. | |
