Validation of Topology Optimized Titanium Uprights for Race Car applications made by Additive Manufacturing
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This thesis work covers aspects of upright design and manufacturing for a four wheel independent drive electric racing car, focusing on simulation-based design and additive manufacturing. A step-by-step overview of the design and manufacturing processes is presented, covering aspects from the initial concept definition until the uprights are mounted on the car. Designing uprights for a racing car is a challenging task, which entails investigations of design methodologies where the strict requirements and performance demands can be optimized. As presented, utilizing simulation-based design using topology optimization, the strict requirements of the upright being the supporting core in the wheel are fulfilled, as well as having high component performance. With a weight of 679 and 550grams, front to rear, and a peak lateral deflection of 0.1mm during cornering all around, the high performance output of the method is evident. Exposed to radial loads up to 7000N and over 5000N axially, optimized for numerous load scenarios with varying load magnitudes and directions, the result is considered beyond what is possible to achieve using conventional design methodologies. Furthermore, to manufacture the complex optimized design, Design for Additive Manufacturing and subtractive machining are also performed. With strict component tolerances and surface requirements, for instane the total-run out requirement for the cylindrical wheel bearing surfaces of 0.02mm with a surface finish of Ra0.4, the produced parts prove it is possible to obtain strict tolerances on AM built parts using conventional CNC-machining. The produced components, being used on the Revolve NTNU Formula Student racing car "Eld" throughout the summer of 2017, practical coherence with the simulation-based design methodology are proved, as well as abandoning the idea that additive manufacturing cannot produce highly loaded, structural parts.