Concurrent Engineering

Final Design

Jed EscovillaJoe FiniBen LyJesse ThompsonGustavo Ortiz

ME 138: Formula SAE Chassis

Goals and Ideas 2010 Chassis

Torsional Rigidity:

370 lb-ft / degree

The Use of FEA

F-SAE 2010 Chassis: Weight

Weight:

Under 63 lbs

The Lighter

The Faster

F-SAE 2010 Chassis: Comfort

Drivers Seating Angle & Front Hoop:

Increase Comfort and Ease Driver Egress

Concurrent Engineering Principles Used

Design for Manufacturing Design for Cost Design for Serviceability

Design for Manufacturing

Redesigned frame has reduced amount of welded joints

Reduced the number of tubing for the frame

Redesign of Front Hoop

2009 front hoop had too many butt welded joints, these are replaced with bends.

Reduction in Frame Tubing

Removed tubing from engine mounting structure

Design for Costs

Manufacturing Costs were reduced by :Replace welds with bending when possibleReducing number of tubes for frame

Material CostsSteel used for frame increased but only by a

small amount to make up for loss rigidity.

Design for Serviceability

Main hoop bracing redesign for engine serviceability.

FEA ANALYSIS AND TESTING

Torsional Rigidity

Without proper rigidity significant frame bending occurs (strain)

With major flexing in the frame, clearances will be affected

Frame flex induces forces not originally intended

Torsional Rigidity testing

Ft-lbs

degreeUnits:

2010 Frame Rigidity

Race Conditions Simulation

Applying loads during race conditions Most extreme case: Turning

FSAE Autocross Conditions

D7.2 Autocross Course Specifications & Speeds

D7.2.1 The following standard specifications will suggest the maximum speeds that will be encountered onthe course. Average speeds should be 40 km/hr (25 mph) to 48 km/hr (30 mph).

Straights: No longer than 60 m (200 feet) with hairpins at both ends (or) no longer than 45 m

(150 feet) with wide turns on the ends. Constant Turns: 23 m (75 feet) to 45 m (148 feet) diameter. Hairpin Turns: Minimum of 9 m (29.5 feet) outside diameter (of the turn). Slaloms: Cones in a straight line with 7.62 m (25 feet) to 12.19 m (40 feet)

spacing. Miscellaneous: Chicanes, multiple turns, decreasing radius turns, etc. The

minimum track width will be 3.5 m (11.5 feet).

F=20.5slugs*44ft/s^2/29.5ft = 1,331 Pounds of Force

OR (66ft/s^2)/(32.2ft/s^2)=2 *Gs

COST

Cost Event – The Cost Event Rules (abbreviated)

1. Standardized Prices – The prices for parts, materials and processes have been standardized and the prices in the official Cost Tables must be used. If you use a part or process that’s not in the table there is a procedure for having it added. The standardized Cost Tables will be published through the FSAE website.

2. No Receipts – Since prices are standardized no receipts are required – except when requesting items be added to the table.

3. No Maximum Cost – You can spend as much as you like on your FSAE car with the understanding that your total cost is a significant factor in your Cost Event score.

FSAE Cost Guidelines

2010 Cost Cost estimate for frame design consisting of

57 tubes and 114 tube ends

Material Costs:

- frame weight = 63.25 lbm

- standardized cost = $4.95/lbm

- material cost = $313.09

Manufacturing

Standardized Costs:

Tube prep = $0.75/end

Tube cut = $1.20/end

Tube weld = $1.20/end

Tube bend = $0.75/bend

2010 Cost

Manufacturing Costs

- 114 welds = $136.80

- 8 bends = $6.00

- 114 tube preps = $85.50

- 114 tube cuts = $136.80

- Total = $365.10

2010 Cost

2010 Cost

Materials Cost = $313.09

Manufacturing Cost = $365.10

Total = $678.19

Old VS New

Cost Reductions• Shorter Chassis• Less Manufacturing Costs

• More bends• Reduces the number of tube ends to be notched and welded• Bending is cheaper than cutting, prepping, and welding ends

2009 ChassisItem Qty CostTube Cuts 130 $ 156.00Tube Prep 130 97.50Tube Welds 130 156.00Bends 4 3.00

Material Costs 306.90

Total Cost 719.40

2010 ChassisItem Qty CostTube Cuts 114 $ 136.80Tube Prep 114 85.50Tube Welds 114 136.80Bends 8 6.00

Material Costs 313.08

Total Cost 678.19

Total Savings

$ 41.21~5.7%

Any Questions?