Blog #6 - Suspension Manufacturing

The suspension team has been continually working on the project regardless of the university closures. The team has finalized the manufacturing process of all the tubings including the 8 front and rear A-arms. The team spent long hours getting the tubings coped, cleaned and welded to the weld bungs and the rod ends. In addition, all the A-arms were painted in a dark blue color by the suspension team. Also, all the suspension tabs were tack welded to the chassis to fix the suspension points and check the assembly process (Figure 1). The damper bridge was also fixed to the chassis tubes and the jigg using bolts. The fabrication process is moving slower than expected due to the amount of time taken for cleaning,coping,and adjusting the steel tubings and the tabs. However, the team is currently on time and is planning to continue working in the FSAE shop.

Figure 1: Suspension tabs attached and welded to the chassis and the jigg

During the work period of March 6 - March 20, the team faced a technical challenge on the rear part of the car. The damper bridge was modeled to be less than ¼” away from the chassis tube due to the geometry that was most suitable for the car’s kinematics. However, during the manufacturing, the damper bridge interfered with the chassis tubes. This issue occurred because the chassis team has slight clearance issues that added up and affected the placement of the damper bridge. The suspension team implemented a solution to overcome the clearance issue by moving the damper bridge ½” upwards (Figure 2). This change changed to motion ratio from being 1.03 to 1.028 . Ideally, the motion ratio should be closer to 1, for the car is expected to function smoothly by having a motion ratio of 1.028.

Figure 2: Damper Bridge new placement ( raised 0.5" to avoid interference).

During the work period of March 20 - April 3, the suspension team will work on manufacturing the anti-roll bars and the bellcranks. Also, it is expected that the university’s machinist will complete machining the uprights during this period. The suspension team will finalize the manufacturing process by the first week of April and will be mid-way in assembling the suspension components to the car. In addition, the team has developed a validation plan and the testing uprights will be machined and validated during this period of time. A demo of the project as well as preliminary validation results will be delivered. The team is anticipating issues when validating the uprights because the university’s facilities will be closed and these facilities were initially chosen to help validating the uprights.