MSc VIVA
- 2. Formula Student Competition in which universities design, build and run their vehicles with the aim of scoring as many points as possible in the following areas: • Design • Business Plan • Cost • Acceleration • Skid Pan • Sprint • Endurance & Fuel Economy Key PointsWhat is Formula Student • Small engine displacement – 600cc • Very narrow coned track • Emphasis on agility not outright power or speed
- 3. • Design a chassis for the 2012 Formula Student Vehicle • Develop an analysis method to help future chassis development Brief Exploration • Performance Increase • Can be confidently manufactured on time • Within budget • Software for chassis analysis • Test of chassis Constraints • Must meet Formula Student regulations • Interface with other major systems; suspension & powertrain • Analysis methods must be usable by future students Timeframe • Final designs to be reviewed in January • Manufactured by 1st May
- 4. Research – Chassis Types Steel Tubular Spaceframe Composite Monocoque • Relatively easy manufacture • Cost effective • Previous experience • Inexperienced in manufacture • Relatively expensive • Possible performance gain
- 5. Research - Chassis Requirements Considerations Constraints • Track & wheelbase • Ride height • Suspension • Engine & drivetrain • Driver Templates • Cockpit template • Frontal chassis template • Roll hoop requirements • ‘Percy’ – 95th percentile male • Weight distribution • Suspension requirements • Variance in driver size • Load paths
- 6. Development Suspension hard points Vehicle Centre Main roll hoop Front roll hoop Steering wheel plane Maximum/minimum driver size Ground plane
- 7. Manufacture 8 Week lead time
- 8. Purpose • Chassis has a major impact on vehicle performance • No current proven simulation model or test equipment Development Model Options • Finite Element Analysis o Optimisation of chassis in design phase • Physical testing o Requires test rig o Time consuming o Vehicle is already manufactured • Physical test work of a previous chassis • FEA simulation of a previous chassis • Validation of modelling and simulation techniques from test work • Model parameters can be used for future chassis designs Conclusion
- 9. Finite Element Analysis Software Package • Solidworks • Abaqus • Other software packages Modelling Methods • Frame constrained to replicate dynamic loading scenarios • Beam element model used o Fewer elements required for a given structure size o Method is readily available and usable in Abaqus o Linear stiffness matrix used Data • Torsional Stiffness o Performance indicator o Comparison to previous frames • High/low stress areas • Comparison of designs o Ultimate stiffness o Mass o Stiffness per unit mass Future use
- 10. Testing Method Hub Boss Steel box section 100mm x 100mm x 5mm
- 11. Testing Procedure • Aim: Measure torsional stiffness • Dial gauges located between the spaceframe and the flatbed Dial gauges • Front clamped down • Rear set-up on pivot Pivot Rear beam • Masses placed on one side of rear beam (5Kg increments) Masses Front beamPhil’s Shoe • Gauges measured at each interval
- 12. Results FEA Results Graph Linear graph – Load applied is directly proportional to angular displacement Test Results Graph Vertical displacement to angular displacement
- 13. Results Comparison of Simulated and Tested Data – With Engine Overall Stiffness (Nm/deg) Front to Centre Stiffness (Nm/deg) Centre to Rear Stiffness (Nm/deg) Tested with engine 1462.75335 1880.519508 6602.482826 Simulated with engine 1273.056176 1598.578421 6251.73906 Simulated Percentage Difference -13.0% -15.0% -5.3%
- 14. Results Comparison of Simulated and Tested Data - Without Engine Overall Stiffness (Nm/deg) Front to Centre Stiffness (Nm/deg) Centre to Rear Stiffness (Nm/deg) Tested without engine 955.5590512 1568.896077 1768.588146 Simulated without engine 1117.957557 1548.504062 4020.847449 Simulated Percentage Difference + 12.3% -1.3% +127.3%
- 15. Results 68 Nm/deg/Kg 72% Increase 34.4 Nm/deg/Kg 39.5 Nm/deg/Kg
- 16. Summary • Chassis designed and manufactured on time • All sub-systems fitted correctly • Mass of 29.5Kg - 29% mass saving over previous spaceframe • Vehicle competed at scheduled events Part 1: Design a chassis for the 2012 Formula Student Vehicle • Simple test rig designed and manufactured • Abaqus model of PFK-01 and HARE 12 created • Validation has proved promising • Further validation work required, particularly regarding engine Part 2: Develop an analysis method to help future chassis development
- 17. Questions