MARCH 2023 - JUNE 2023

PROJECT OBJECTIVES


TECHNICAL ATTRIBUTES / NOTES


DESIGN NOTES

BACKGROUND

I was given a general sense of direction - build something similar to previous 'hanging car' displays built by the team at the Pedersen Automotive Museum and GFTX, but make it installable on-site in Tesla Showrooms. The idea being to create the pilot display that could be replicated across Tesla showrooms worldwide. I began this with very crude 'napkin sketches' of bodies on SolidWorks, presenting multiple concepts including a box frame base, two triangular bases, a pergola display, a cantilever display with a back wall, and a pedestal style display.

EARLY DESIGNS

The shortlist turned into pergola, cantilever, and pedestal displays. I then used CATIA to download models of the bodies and relevant components, and begun to map out in detail how each display could look. After making these mockups on SolidWorks, I presented these concepts to the director of the project, outlining the tradeoffs between cost / speed of implementation, space needed, and scalability of each design. The pedestal display was selected due to it's ease of implementation and scalability.

PROTOTYPING 

With a design direction selected, I put the engineering into the design to make it work. I begun by creating a BOM of the expected components we would utilize, then calculated the expected loads on the structure through hand calculations. With the maximum expected loads, I calculated the minimum cross section needed for a single column to support this structure, so I could select a size of tubing to begin the design with. 

After selecting this stock of tubing, I built out the entire structure on CAD and did an FEA simulation for a static load using SolidWorks simulation. I utilized a large factor of safety of 8 as safety was paramount and I did not have the time to conduct a more thorough  analysis nor the need to optimize for cost. I used my simulations to refine the design, which ultimately meant I had to go with a larger stock of tubing. 

I then purchased material from a local supplier, my teammates sourced a scrap body, and we began prototyping the structure and exploded subassemblies with a team of 3 permanent and 2 rotating technicians. One of my teammates welded the pedestal structure together while I prepared the cuts and directed the prototyping operations. With the pedestal complete, we used a forklift to load the body onto it and test its stability. While the structure held, there was a lot of lateral swaying, so I reinforced the T structure with gussets - which I originally had dismissed for aesthetic considerations.

We finished prototyping the other subassembly mounts and I presented the prototype to the project stakeholders. Upon approval, I made engineering drawings to outsource the fabrication of the final version, which had some aesthetic differences in laser-cut Tesla logo base plates and powder-coated finish. This team shipped the finished pedestals back to GFTX, and upon arrival I validated their specification. I found that they had been built backwards in the sense that the front mount was taller than the rear mount, when the opposite was intended. The drawing was correct, but not clear enough - leading to the mistake. Lesson learned. 

We rolled with the change as there was no more time to re-do both pedestals. We could not swap them out as the front subframe mounting points are shorter than the rear, and the crossbar was cut to size. We tested the pedestal assembly on site to ensure it worked properly and I uncovered an issue I had not prototyped. I added a connecting plate to fasten the front and rear pedestals together to increase the assembly stability, but I had not considered the weld bead size. I designed a plate that was the same height as the spine, but without considering the weld bead the plate did not sit flush with the base and caused a misalignment of the hole and slots. I had designed some allowance into the slot and hole fit, which thankfully was enough to allow us to bolt the assembly together with a bit of elbow grease and a hammer. 

LOGISTICS AND INSTALL

We assembled as much as we could at GFTX but had to compromise by not installing some components to minimize the risk of damage during transportation. I coordinated the logistics of the transport, the permits needed at the install location, and the team of technicians needed for the install. We arrived on site at 8pm and worked on the install through to 4am.

PRODUCTION 

To make this process repeatable, we tracked all the parts we used to build this display on a BOM with pictures to easily help a 3rd party replicate the process. I made a few work instructions regarding installation steps for some key areas including how to load the body onto the pedestals and how to attach the wheel hubs and suspension.