University of Twente Student Theses
Analysis of Dynamic Loads induced by Spinning Gondolas on a Roller Coaster
Hoorn, H.E. van den (2019) Analysis of Dynamic Loads induced by Spinning Gondolas on a Roller Coaster.
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| Abstract: | The competition between rollercoaster manufacturers to build the most thrilling rollercoasters has always been fierce. In an attempt to design more spectacular rides than their competitors, rollercoaster manufacturers continuously try to push the technical limits without compromising the safety of the passengers. The design of safe rollercoasters according to the prevalent regulations has the first priority within the industry, in spite of the eagerness to build ever more spectacular rides. Partial redesigns of rollercoasters due to violations of the safety regulations or excessive maintenance costs have namely proven to be a costly endeavour. Operating on the limits while minimizing the risk of exceeding them makes the design of rollercoasters a delicate process. The technical specifications of rollercoasters can be calculated beforehand with ever more accuracy, thanks to the progress in computer-aided modelling. The development of sophisticated software enables engineers to predict accelerations, forces, stresses, and other important parameters during the design stage. Due to limited computational power, a trade-off should often be made between accuracy and the computational effort though. The loads induced on the main chassis beam of a spinning rollercoaster vehicle are typically converted into a minimum number of loadcases, which consequently leads to a reduction in computational effort at the costs of accuracy. A spinning rollercoaster is characterized by a gondola that pivots freely under the effects of track dynamics and passenger weight distribution. The loads induced on the beam are converted into loadcases for a subsequent finite element analysis, which should reveal the resultant stresses and beam deformation. Due to the desire to minimize the computational time, the forces and moments are represented by a minimum number of relatively conservative loadcases. In other words, the forces and moments described by the loadcases are more severe than the actual loads acting on the main chassis beam. The predicted stresses and deformations are consequently larger than what can be expected based on the actual loads. This conservative approach might lead to more conservative rollercoaster designs, which conflicts with the vision of designing the most thrilling and spectacular rollercoasters. Therefore, a need exists for a general methodology that is capable of accurately predicting stress and deformation levels, while minimizing the increase in computational effort with respect to the conventional yet conservative approach. Prior to the development of such a methodology, a kinematic model of a spinning rollercoaster should be created first. The report commences with the creation of a realistic kinematic model, from which the forces and moments acting on the main chassis beam can be extracted. Hence, the multi-body model aims to describe the dynamics of a spinning rollercoaster vehicle as realistically as possible by specification of the correct constraints and joints between the vehicle components and at the wheel-track interface. The normal forces at this interface are constantly measured and used for the real-time calculation of the bearing and rolling frictional forces. Simulations are additionally performed to determine the drag coefficient of the gondola at various velocities. Hence, the drag forces acting on the gondola and the chassis can be computed at each time-step as a function of the vehicle velocity and gondola rotation. The inclusion of these friction and drag forces ensures that the rollercoaster vehicle travels along the track lay-out with a realistic pace. The velocity of the vehicle and the rotation of the gondola are prescribed by a reference profile at certain track sections, so the vehicle can travel along the entire track lay-out. The vehicle should accelerate from the station up to the constant velocity that has been prescribed on the lifthill, while in the meantime the gondola is kept at its initial position. On the brake-section and subsequently at the re-entry of the station, the vehicle is braked to a standstill while the gondola is rotated back to the regular configuration. The dynamic behaviour of the spinning rollercoaster vehicle can be accurately described thanks to the previously-described additions to the kinematic model. |
| Item Type: | Essay (Master) |
| Clients: | Van Velzen Extern Engineering, Apeldoorn, Netherlands |
| Faculty: | ET: Engineering Technology |
| Subject: | 52 mechanical engineering |
| Programme: | Mechanical Engineering MSc (60439) |
| Link to this item: | https://purl.utwente.nl/essays/79241 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
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