2005 Chassis

This is our chassis of our vehicle. The chassis was mainly designed by the 2004 FSAE team. Our objectives were to improve on the design by decreasing weight while keeping stiffness the same. Using IDEAS FEA was performed to locate lower stressed members of the chassis. By decreasing the wall thickness and outer diameter of the lower stressed members, I was able to decrease the weight of the chassis by 17%.

I had to consider the moment of inertia of the tubes to keep the stiffness high while lowering the weight. By plotting moment of inertia vs. outer diameter & moment of inertia vs. wall thickness I could determine a suitable tube size. Cost, availability, and weldability were also contributing factors. After speaking with a TIG welder at Tool Tec (Company that welded our frame) I found that 0.035in was the minimum thickness on the wall to allow low distortion and heat input. A greater wall thickness acts as a heat sink allowing for less heat distortion and affect on the heat affected zone of the weld.

By selecting 5/8" outer diameter with a wall thickness of 0.065" 1020 CREW tubing, I was able to save 13 lbs on the chassis, weighing in at 64 lbs. The main structural components of the chassis consists of 1020 DOM 1" OD steel tubing. The wall thicknesses vary from 0.095" to 0.049". 1020 DOM tubing was chosen for its superior strength to weight ratio. DOM tubing has a much higher tensile strength then cold drawn & hot rolled tubing. 4130 (Chrome Moly) was considered however 4130's did not fit our benefit to cost analysis mainly due to its high price. The chassis was TIG welded for high quality, low heat input welds.

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