University of Delaware Department of Mechanical ... · PDF fileProject Scope Sponsored by Mike...
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Project Scope Sponsored by Mike Hawley from W.L. Gore and the Mechanical Engineering Department at the University of Delaware, Team FSAE Suspension was assigned the task of designing and manufacturing an efficient, highly-adjustable functioning suspension system for the 2010- 2011 FSAE car. Final Suspension Configuration Performance Evaluation & Validation Glossary of Terms University of Delaware Department of Mechanical Engineering and Mike Hawley SETH BECKLEY, KEVIN GYGRYNUK, JOSH HILFERTY, MICHAEL TERI Problem Background The Formula SAE® Series competitions challenge teams of university undergraduate and graduate students to conceive, design, fabricate and compete with small, formula style, autocross racing car. Over the course of three days, the cars are judged in a series of static and dynamic events including: technical inspection, cost, presentation, and engineering design, solo performance trials, and high performance track endurance. Anti-Dive & Anti-Squat The above suspension design represents the final iteration of the optimization process based upon kinematic evaluation and force analysis. The system shown is capable of withstanding the braking and cornering forces that will be experienced during Formula SAE competition, as well as maintaining a significant factor of safety under unforeseen impact scenarios. The final design meets the performance criteria while providing a level of adjustability for suspension tuning. The A-Arms were designed to accommodate the dynamic camber requirements. A kinematic evaluation informed the design process, and the graphical results are displayed below. Detailed Design Key Metrics and Target Values Force Analysis and Rocker Design The force analysis on the final design centered on maximum cornering and braking forces estimated during competition, and a goal of structural integrity through a 5g vertical suspension impact. The estimated braking and turning values were conservative, and surpassed the benchmarked 1.4g expected in competition. The rockers were designed to optimize the travel of the shock absorbers. Adjustability Considerations The final design incorporates the adjustability desired by the customer. The adjustable components are: A-Arm length (to optimize dynamic camber), A-Arm mounting configuration (to optimize anti-dive/anti-squat), and wheel camber (to set the camber). The FSAE competition vehicle will not be completed until the end of Phase 4. The performance evaluation of the complete suspension system cannot be completed until the car is assembled and driven. However, a test plan has been developed by Team FSAE Suspension to analyze the performance of the suspension design by measuring key performance characteristics under driving conditions. This test plan manual will be presented to the UD FSAE club, so that testing and tuning can be performed over the winter and spring semesters. Additionally, to determine the achievement of the geometric target values, the suspension was assembled onto the partially completed frame and measured. Outlines of the performance tests to be administered are given below: Measuring Camber Effectiveness: Tire Temperature Analysis The efficiency of the camber, ride, and roll rates can be measured by analyzing the tire temperature distribution after 5-10 track laps. Each tire’s temperature will be measured at three locations on the tire: 1” from the outside shoulder, 1” from the inside shoulder, and at the center of the tire. Measuring Load Transfer: G-Force Analysis An onboard computer will record and output acceleration measurements at every point around the track. The acceleration can be used to the resultant G- forces. Measuring Jounce, Roll, and Anti-Squat/Anti-Dive: Direct Measurement These performance targets will be evaluated by directly measuring them as the car is put through testing. Under maximum braking, accelerating, and cornering conditions, the properties listed will be measured, and from their analysis the car will be fine-tuned to maximally achieve the target values. During the early stages of the project, the key metrics were determined through research of suspension design theory. Target values were then formed through conference with the advisor and sponsor, geometric and kinematic calculation, and in-depth research of current successful cars. The geometric target values all directly affect the performance of the car in cornering, acceleration, and braking conditions. A few of the key metrics and their target values are given below: • Roll Center: (determines roll stability and roll characteristics) Stable, < 2" vertical movement over 4 degrees of body roll, ~3” height at neutral • Camber: (determines cornering forces and stability) Static: -2⁰, negative camber gain on outside wheel, positive on inside wheel, during cornering • Caster Angle: (determines road-to-driver feedback and directional stability, adds to camber) 0-5 degrees • Roll Rate: (Determines performance under cornering rolling loads) 148 lbs/in • Ride Rate: (determines wheel forces to cause suspension movement) 20,000 lb-ft/rad Cost Overview Team FSAE Suspension was given a budget of $1000 with which to work. The team was able to meet all of the projects goals and requirements while staying within this budget. A breakdown of the project expenses is given here. Materials Parts Other Total $322 $550 $100 $972
Transcript of University of Delaware Department of Mechanical ... · PDF fileProject Scope Sponsored by Mike...
Project Scope Sponsored by Mike Hawley from W.L. Gore and the Mechanical Engineering Department at the University of Delaware, Team FSAE Suspension was assigned the task of designing and manufacturing an efficient, highly-adjustable functioning suspension system for the 2010-2011 FSAE car.
Final Suspension Configuration
Performance Evaluation & Validation
Glossary of Terms
University of Delaware Department of Mechanical Engineering and Mike Hawley SETH BECKLEY, KEVIN GYGRYNUK, JOSH HILFERTY, MICHAEL TERI
Problem Background The Formula SAE® Series competitions challenge teams of university undergraduate and graduate students to conceive, design, fabricate and compete with small, formula style, autocross racing car. Over the course of three days, the cars are judged in a series of static and dynamic events including: technical inspection, cost, presentation, and engineering design, solo performance trials, and high performance track endurance.
Anti-Dive & Anti-Squat
The above suspension design represents the final iteration of the optimization process based upon kinematic evaluation and force analysis. The system shown is capable of withstanding the braking and cornering forces that will be experienced during Formula SAE competition, as well as maintaining a significant factor of safety under unforeseen impact scenarios. The final design meets the performance criteria while providing a level of adjustability for suspension tuning. The A-Arms were designed to accommodate the dynamic camber requirements. A kinematic evaluation informed the design process, and the graphical results are displayed below.
Detailed Design Key Metrics and Target Values
Force Analysis and Rocker Design The force analysis on the final design centered on maximum cornering and braking forces estimated during competition, and a goal of structural integrity through a 5g vertical suspension impact. The estimated braking and turning values were conservative, and surpassed the benchmarked 1.4g expected in competition. The rockers were designed to optimize the travel of the shock absorbers.
Adjustability Considerations The final design incorporates the adjustability desired by the customer. The adjustable components are: A-Arm length (to optimize dynamic camber), A-Arm mounting configuration (to optimize anti-dive/anti-squat), and wheel camber (to set the camber).
The FSAE competition vehicle will not be completed until the end of Phase 4. The performance evaluation of the complete suspension system cannot be completed until the car is assembled and driven. However, a test plan has been developed by Team FSAE Suspension to analyze the performance of the suspension design by measuring key performance characteristics under driving conditions. This test plan manual will be presented to the UD FSAE club, so that testing and tuning can be performed over the winter and spring semesters. Additionally, to determine the achievement of the geometric target values, the suspension was assembled onto the partially completed frame and measured. Outlines of the performance tests to be administered are given below:
Measuring Camber Effectiveness: Tire Temperature Analysis The efficiency of the camber, ride, and roll rates can be measured by analyzing the tire temperature distribution after 5-10 track laps. Each tire’s temperature will be measured at three locations on the tire: 1” from the outside shoulder, 1” from the inside shoulder, and at the center of the tire. Measuring Load Transfer: G-Force Analysis An onboard computer will record and output acceleration measurements at every point around the track. The acceleration can be used to the resultant G-forces.
Measuring Jounce, Roll, and Anti-Squat/Anti-Dive: Direct Measurement These performance targets will be evaluated by directly measuring them as the car is put through testing. Under maximum braking, accelerating, and cornering conditions, the properties listed will be measured, and from their analysis the car will be fine-tuned to maximally achieve the target values.
During the early stages of the project, the key metrics were determined through research of suspension design theory. Target values were then formed through conference with the advisor and sponsor, geometric and kinematic calculation, and in-depth research of current successful cars. The geometric target values all directly affect the performance of the car in cornering, acceleration, and braking conditions. A few of the key metrics and their target values are given below: • Roll Center: (determines roll stability and roll characteristics) Stable, < 2" vertical movement over 4 degrees of body roll, ~3” height at neutral • Camber: (determines cornering forces and stability) Static: -2⁰, negative camber gain on outside wheel, positive on inside wheel, during cornering • Caster Angle: (determines road-to-driver feedback and directional stability, adds to camber) 0-5 degrees • Roll Rate: (Determines performance under cornering rolling loads) 148 lbs/in • Ride Rate: (determines wheel forces to cause suspension movement) 20,000 lb-ft/rad
Cost Overview Team FSAE Suspension was given a budget of $1000 with which to work. The team was able to meet all of the projects goals and requirements while staying within this budget. A breakdown of the project expenses is given here.
Materials Parts Other Total
$322 $550 $100 $972
