for Formula SAE is a worldwide collegiate competition hosted by the
Society of Automotive Engineers (SAE). Teams
composed of undergraduate and graduate students design,
build and compete
a formula style
racecar in the
FSAE series. In competitions, teams score points
by delivering in four main
events: design, cost,
marketing, and performance events.
SAE is an annual racing competition where student organizations from different
universities participate with a small scale Formula style race car.
“Designing, building, and racing” – these three words are probably
the cornerstones of FSAE competition. From ideation to design board, from CAD
modeling to fabrication, from machining to lubrication, from testing to
tweaking, and last but not the least, racing and winning – all are blended
together in the PG Racing dream. A cliché definition of FSAE cars would
probably go something like this – “single-seat, open-wheeled, open-cockpit
performance race car”. PG Racing is the official representative of Gdansk University
of technology in the FSAE competitions held around the Europe. Teams are graded
in the competitions based on their performance in different areas such as
presentation, design, cost effectiveness, acceleration, skid-pad, autocross,
fuel economy and endurance of the car.
for teams to be successful in these
competitions, their cars must be built to very strict
specifications or else they will
be disqualified from the
competition. These specifications can be found
in the official most up?to?date FSAE rules on the web.
system of PGR
diving into the world of carbon fiber, it is worth getting a good grasp of the
suspension system: a suspension system of a car is a system of springs, shock
absorbers and linkages that connects a vehicle to its wheels and allows
relative motion between the two. Various geometries have been taken into
account while designing the suspension system for the FSAE cars. There are
various geometries that
suspension systems can
take in formula one car. The most
widely?used suspension geometry, even in professional?sized formula cars
and the one used by TU
Gdansk`s FSAE team is the double
wishbone design. The double wishbones, shown in figure
2?1 on the
following page are most commonly called A?arms because of their
resemblance to the letter
21: Front Aarms on PGR 2017 formula
is also important to understand the concepts of sprung and unsprung masses in
order to design and engineer an effective suspension system. In a suspension system,
the sprung mass
is the part of the car that is supported by the car’s suspension system. The engine,
the frame, and everything within
the frame of the
car are part of the sprung mass system of the car.
The unsprung mass on the other hand is the part of the car
that is not supported by the suspension. This generally includes the wheels,
brakes, tires, and a few other
frame of the car.
The A?arm design
uses a total
of 16 tubes, 4 on each wheel
of the car.
These tubes, historically made of steel
on formula car suspensions and especially on PGR
formula cars make up a significant portion
of weight of the car.
PGR’s 2017 car’s
arms weighed a total of 6.49 lbs.
In a competition where
the weight to power ratio
matters significantly, FSAE teams always strive to design and engineer a car that is as light as possible yet still
structurally sound and that delivers
maximum power to the wheels.
By using carbon fiber tubes to replace the 16
steel tubes the total weight of the A?arms
can be reduced by at least 50% and the overall stiffness of the tubes
can be maintained or even increased.
A?arms act as structural members of the suspension, the push rod, also shown in figure 2?1, acts as the spring?damper component of the car’s suspension.
push rod, and sprung and unsprung masses of the suspension system
all need to be carefully designed so that
optimal car performance is reached on the race track.
Carbon Fiber Tubes
Types of carbon fiber
tubes are most
commonly manufactured using
two methods: Pultruding and roll?wrapping.
Pultruded – Pultrude Carbon Rods and Tubes are
manufactured for maximum rigidity with minimum mass. Pultrusion orients the
fibers lengthwise down the shaft for maximum structural rigidity. Carbon fiber
contributes to the rigidity, while minimizing weight. Carbon is 70% lighter
than steel, 40% lighter than aluminum, and three times the stiffness of either
for the same weight.
The Carbon fiber has a negative coefficient
of thermal expansion, meaning it expands as the temperature lowers. The resin
matrix, on the other hand, has a positive coefficient. The net result is
virtually no expansion or contraction of the composite over a wide range of
Figure 31: Pultruded
tube (left) and rollwrapped tube (right)
18.5 msi / 127 GPa
Thermal Expansion Coefficient
-0.1 ppm/cm3 / -0.2 ppm/°C
Glass Transition Temperature
Bisphenol Epoxy Vinyl Ester
Roll-wrapping involves the applying of resin pre-impregnated
composite fiber cloth (Pre-Preg) around a mandrel. The outer diameter of the
mandrel thus determines the inner diameter of the final tube. The mandrel and
cloth are then spiral wrapped with a consolidation tape under tension to hold
the laminate in place during the curing phase. After curing, the mandrel is
extracted to leave the tube ready for machining or finishing as necessary.
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