Steering Column Support

grabcad

Chippewa Racing Formula SAE Steering Column SupportDesigner: Austin BrittainAdvisor: Pablo Parraga-RamirezSchool: Central Michigan University3D Printing Method: Polyjet on Objet Connex3Material: Rigid OpaqueFor this year’s Extreme Redesign Challenge, I decided to rethink the steering column support for the Chippewa Racing Formula SAE race car. The previous design was manufactured from welded steel tubes and was difficult to reliably manufacture to the necessary precision. It also lacked rigidity which had a negative effect on performance as well as the fit and finish of the completed vehicle.I had wanted to try out the generative design ever since I saw a picture of a generatively designed bracket used by General Electric. It strikes me as a technology with massive disruptive potential. My school recently acquired a Renishaw AM 250 metal powder bed laser fusion machine and I was looking for a part that could take advantage of its incredible capabilities. Fusion 360 began offering a generative design feature in 2018. Opportunity was knocking.I started by importing the front roll hoop from the chassis model into fusion. I added cylinders to represent the steering column and bearings, then I designed the attachment points where the part would interface with the frame. Finally I drew a body where I wanted the steering support to be constructed.The chassis, bearings,and shaft were designated as Obstacle geometry, the mating surfaces for the bearings and bracket were designated Preserve geometry, and the bounding body was set as a staring shape. I selected my load cases based on data from http://www.fsaeonline.com/content/Cockpit%20Control%20Forces%20SI%20SAE.pdf. The material was set to 316L stainless. Its low yield strength is not ideal for high performance racing parts, but it is what our machine is currently configured for. Ideally a marraging steel would be used if the part was to be welded to the frame. The part could be significantly lighter if made from aluminum or titanium, but would have to be brazed instead of welded.The simulation was started and allowed to run to completion. In all, it took several hours. In the end I selected my favorite from the 16 generated models and exported it to another fusion model. There I cleaned up the model.3D printing parts out of metal is expensive so it as important that as much as possible is known about the design as possible before it is manufactured. Failure of any part can be a huge setback to a race team and failure of part of a control system could be dangerous. Because of this it is important that all stakeholder are kept up to speed during the design process. Stratasys' Objet Connex line can produce communication aides for designers such a models with full color simulation results mapped onto the surface. This can shorten the design cycle while making sure team members are safe and well informed.