Multi-Domain Multi-Material Topology Optimization of a Roller Coaster Vehicle Bogie Subject to Multiaxial Fatigue Constraints

This research, conducted in collaboration with Dynamic Structures, aims to address the unique challenges posed by roller coaster wheel assemblies (bogies), specifically focusing on multiaxial fatigue topology optimization. Roller coaster bogies endure complex multiaxial loading conditions and require specialized fatigue constrained optimization due to their intricate loading, operating conditions, and repetitive load time histories. Existing methodologies often overlook the intricacies of roller coaster design and engineering, and concentrate primarily on simpler loading cases, and isolate different components into their own finite element analyses, neglecting the crucial aspect of how different components interact with one another. The objective of this research is to minimize the volume of a bogie while maintaining its structural integrity and potentially increasing its service life over the expected number of operational cycles. Fatigue in materials is a phenomenon that arises when specific stress and strain concentrations surpass the material's fatigue endurance limit. This can result in the formation of cracks and a gradual deterioration of the material's structural integrity. High-cycle fatigue poses a considerable risk for structures subjected to cyclic loading, as it has the potential to culminate in abrupt and unexpected structural failures. In such cases, the cumulative effect of cyclic stresses over time can compromise the material's ability to withstand load-bearing demands, jeopardizing the safety and reliability of the entire structure. The proposed methodology and effectiveness of implementation is validated through a comprehensive analysis of three case studies, wherein material removal ranged from 25% to 35%. To solve the complex multiaxial fatigue problem in roller coaster bogies, a multi-domain topology optimization is used, resulting in a solution that incorporates three discretely assigned materials. In total, approximately 34% of the volume of the designable domains is removed from the bogie, resulting in a global volume reduction and mass reduction of approximately 22% and 23%, respectively, in line with the validation models. The achieved service life of the bogies in this study reaches 991,100 cycles with minimal damage of 1.009E-6 accrued per cycle, 334,100 cycles above the current design life. Static strength and fatigue utilization values are used to verify proper fatigue optimization within the solutions.

Department dc:contributor.department

Mechanical and Materials Engineering

Author dc:creator

• Eisen, Dylan

Advisor dc:contributor.supervisor

• Kim, Il Yong

• Multiaxial fatigue
• Fatigue life
• Fatigue damage
• Topology optimization
• Roller coaster bogie
• Volume reduction

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1974/32570

OAI identifier oai:identifier

oai:queensu.scholaris.ca:1974/32570