Analytically test frame using vibration analysis Use results of test to find resonant frequencies,

which can be used to determine chassis stiffness under different loading conditions

Knowing the vibration mode “shape” and frequency can approximate frame stiffness

FSAE is an international collegiate open wheel race car design and dynamic competition regulated by the Society of Automotive Engineers

**The UD Formula SAE team will compete in the 2011 FSAE West competition in California

Task: Design, Fabricate, and Test a steel space frame chassis and fuel system

Frame:

Focus on Manufacturability

Competitive Performance

•Torsional and Flexural Rigidity

• Weight

• Center of Gravity Height

Seamless car system integration

Fuel System:

Includes fuel tank and fuel pump

Metric Target Values (ordered by relative weight)

Metric Target Value

Manufacturability 225 Hrs

Long. Torsional Rigidity 1800 ft*lb/deg

Flexural Rigidity 4500 lb/in

Weight > 75 Pounds

Vertical Center of Gravity > 10 Inches

Steel Space Frame Current standard in FSAE Low cost, manufactured with conventional tools Easy to repair and modify Low strength/weight ratio means a heavier structure Full Monocoque Pinnacle of racing technology Enhanced strength/weight ratio over steel frames Exotic materials add cost, difficult to manufacture Difficult to repair/modify, poor accessibility to critical systems Difficult to obtain sufficient pull out strength at mount points

Hybrid Monocoque/Spaceframe Realize benefits of monocoque while avoiding rear mounting complications

All vehicle systems must fit onto the chassis

Must comply to all 2011 FSAE rules Maximum Budget of $1000.

A weighted design matrix was used to select a chassis concept

A steel space frame was chosen as the best choice given time, money, and resource constraints.

Utilize a wooden spine jig that fixed members parallel to the bulkhead

Once the parallel members were in place, the connecting tubes were welded in place

An in tank fuel pump was selected over a out of tank fuel pump due to amperage draw, high flow and readily available.

Fuel Tank was designed based on average fuel economy of the engine.

Torsional Rigidity Bolt the rear of the frame to a rigid member.

Support the center of the frame to decrease bending. Using truss and weight system apply a moment. Measure with a digital level.

Flexural Rigidity Support the frame from underneath both

suspension boxes and load the frame directly between those two supports with weights. Measure with ruler.

Metric Target Value Measured Value

Manufacturability

Torsional Rigidity

Flexure

Weight

Vertical Center of Gravity

**Metrics chosen based on Top Teams of 2010 FSAE Competitions and Previous UD Chassis

Over 30 iterations of possible frame design were preformed in SolidWorks Finite Element Analysis.

The frame design that performed best with respect to the metrics was chosen

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fsae.com