Transcript 2014-2015 ODU FSAE Car

2014-2015 ODU FSAE Car
Ashley Wyatt
Xavier Thompson
Matt Galles
Bobby Costen
Chris McHugh
Randy Fulcher
Frame
Suspension
•Handle course impacts from imperfections
•Increase contact patch
•Dynamic system
Prior to designing:
 Camber angle
 Caster angle
 Kingpin Inclination (KPI)
 Steering axis angle
 Scrub radius
 Included angle
 Toe in
 Toe out
 Roll Center
Camber Angle
 Critical
 Width of contact patch
 Negative improves handling in corners
 Prevent understeer
http://www.benzworld.org/forums/w126-s-se-sec-sel-sd/1678465-rear-tire-wear-due-negative-camber.html
Caster Angle
 Automatically realigns tires
 Improves ‘directional feel’
 Adds negative camber during turns
http://www.toyota-4runner.org/5th-gen-t4rs/167451-fitting-285-tires-lr-ucas-adjusting-caster.html
Ackermann Steering Geometry

The intention of Ackermann geometry is to avoid the need for
tires to slip sideways when following the path around a curve.

The geometrical solution to this is for all wheels to have their
axles arranged as radii of a circle with a common center point.
Ackermann Steering Geometry
 Rear wheels are fixed and
a center point must be on
a line extended from the
rear axle.
 This line intersects the
axes of the front wheels
and requires that the
inside front wheel is
turned, when steering,
through a greater angle
than the outside wheel.
Carbon Fiber Wheels
Reduction in weight
Increases fuel efficiency
Higher tensile strength than most metals
Stats from Material Testing at Ohio
State University
https://kb.osu.edu/dspace/bitstream/handle/1811/58422/carbon_whe
el_thesis_FINAL.pdf?sequence=1
Aluminum Rim Piece:

Moment (in*lbs.)
=3900

Weight (lbs.) =7.1

Deflection Angle
(Degrees)= 0.036
 Stiffness
(in*lbs./Degrees)
=84782.6
 Specific Stiffness
(stiffness/lbs.)
=11941.2
Carbon Fiber Rim Piece:
 Moment (in*lbs.)=
3900
 Weight (lbs.)= 1.73
 Deflection Angle
(Degrees) =.21
 Stiffness
(in*lbs./Degrees) =
18571.4
 Specific Stiffness
(stiffness/lbs.)=10734.9
Rear Suspension
 Change from Pull-Rod to Push-Rod System
 Suspension travel will be increased
 A-Arms overdesigned to handle additional bending moments
 Upper A-arm carries weight of vehicle
Upright Design
 Weight Reduction
 Adjustability
 Room for Brake Caliber Attachment
 Adjustable Toe- In /Out