This paper discusses the development of composite materials applications in the performance automotive industry and how the advances made can affect the commercial automotive industry.

1. PROJECT REPORT MEEG 4023 Shamus Stewart
Mark Edwards
Composites in Automotive Racing
INTRODUCTION
In the past two decades, composite materials have become increasingly popular in
automotive racing. Most drastically in Formula 1 racing where teams are well funded and can
afford research and development of advanced composite materials. McLaren’s racing team
introduced the first entirely carbon fiber chassis in 1980 (pictured below). Excluding the wheels
and engine, 85% of a formula 1 race car is made from composite materials. This is largely due to
the competitive advantage that comes with minimizing the weight of each component on the car.
Formula 1, NASCAR, and other racing circuits have minimum vehicle weight regulations.
However, teams still strive to minimize weight wherever possible so weight ballast can be added
to the car allowing precise tuning of the vehicle’s center of gravity and handling characteristics.
There are numerous other benefits of composites including their durability, stiffness, thermal
conductivity, and energy absorption characteristics. Vehicle safety has been significantly
improved since the introduction of composite materials. Composite survival pods and impact
protection components have played huge roles in decreasing the fatality and serious injury
statistics in automotive racing.
Fig A. The original composite F1 chassis, McLaren MP4-1 [6]

2. VEHICLE SAFETY
The development of composite materials has led to many innovations in in vehicle safety.
F1 teams continue to develop extremely strong and durable carbon fiber survival pods and
energy absorption attenuators. NASCAR has introduced a composite driver’s seat that is much
stiffer than its aluminum predecessor [1]. During the 1960’s the rate of fatal and serious injury
within formula 1 was 1 in every 8 crashes [2]. Through implementation of many new safety
regulations by the FIA, the period of 1980-1992 saw a 6-fold reduction in fatalities and serious
injuries. Those new regulation were largely due to the introduction of composites into the sport
in 1980 by the Mclaren team with their composite chassis [2]. The phenomenal survivability of
race cars is accomplished with a combination structural stiffness and energy absorption
capabilities.
One of the most important traits of any racing vehicle is its ability to absorb impact
energy in the event of a crash. Most racing vehicles have “crumple zones”, as they’re known,
located at the front, rear, and sides. These crumple zones consist of structures which are designed
to dissipate energy through yielding. This dissipation of energy helps gradually bring the vehicle
to a stop and thus avoiding huge g loads being transferred to the driver. Historically, impact
attenuators have been of metallic composition. For metallic structures, the absorption of energy
is achieved by plastic deformation. Carbon fiber composites have been shown to have even
better energy absorption characteristics and are replacing metallic impact attenuators in many
racing circuits. As opposed to metallic materials, in composites energy absorption is achieved by
material diffuse fracture which is a brittle failure mode [3]. Because weight reduction and
vehicle stiffness are also of extreme importance, composites are the ideal material for most
impact attenuators in race cars. In many instances these impact absorption members must also
serve as load bearing members and are subject to tight geometrical constraints for packaging and
aerodynamic reasons. Obviously the shape of the nose on F1 cars is crucial to optimizing
aerodynamic performance of the vehicle but that same component must dissipate energy in the
event of a forward collision. Another example is the RIMP (rear impact member), shown in fig 1
below, which is an impact attenuator but also must react loads from the rear wing and rear
suspension linkages among other design constraints.

3. Fig 1. BAR Honda 050, Gearbox and RIMD Structure [2]
From an engineering standpoint, these types of components that are intended to catastrophically
fail in a controlled manner when an impact load is applied but still bear structural loads can
present immense challenges for the designer.
The energy dissipation that is achieved by metallic components is the result of the work
required to plastically deform the part and form “plastic hinges” which progress along the part.
This concept can be illustrated by examining the axial collapse of a metal tube. Figure 2 shows
the displacement to force behavior of a thin walled metal tube subject to impact loading.
Fig. 2. Axial collapse of ductile metal tube [2]

4. For composite materials the dissipation of energy is achieved by the work required to
fracture the brittle fibers imbedded in a brittle matrix. The primary energy absorbing mechanisms
of fiber-reinforced composites are:
 Cracking and fracture of the fibers
 Matrix fracture
 De-bonding (pull-out) of fibers from the matrix
 Delamination of the laminate
Figure 3 shows typical force displacement behavior for a composite tube. The photograph shows
successful failure modes of a 50mm cylindrical tube.
Fig. 3 axial crushing of composite tube [2, 3]
One of the major challenges in designing these components is avoiding global buckling of the
part (shown in Fig. 3 to the far left) and arranging the column of material such that a destructive
“process zone” can progress through the part in a stable manner without deceleration peaks [2].
The typical design process for energy absorbing components can be broken down into three
different phases. The first is to develop analytical models that reproduce crash phenomenon, the
second is to implement numerical model to discretize the structure and perform FEA, and the last
is to perform experiments to prove out the design. Much research has been done to improve the
accuracy of numerical analysis methods used to predict a composite components impact loading
response. Because these impact attenuators play such a crucial role in driver safety, they must be
subject to rigorous static, dynamic, and fatigue testing before being cleared for installment on a
racing vehicle. The FIA requires official impact test of all energy absorption structures and has
set minimum peak force requirements for each component. These test usually involve impacting

5. the component with a large mass moving at a particular velocity. The photograph below is of an
official FIA test of a RIMP.
FIA rear impact test, impact structure is fitted on dummy gearbox [4]
The survival cell is the last defense a driver has against his/her body coming into contact with
outside entities in the event of a crash. The survival must be extremely strong, durable and, as
with all other racecar components, be as light as possible. For those reasons Fiber reinforced and
honeycomb composites are used in place of metallic material options. The standard construction
used in F1 monocoque consists of two thin carbon composites skins bonded to aluminum
honeycomb core [5]. As opposed to energy absorbing structures, the survival pod is designed not
to fail at the maxim loads that would ever be experienced in a racing crash. The FIA has
stringent requirements for the survival pod also, but these static test are intended to prove the
survival pods ability to deny intrusion of foreign objects. For example one requirement states the
side of the cell must hold a load of 30Kn for a period of 30s [3]. The addition of these
regulations to the design requirements have resulted in chassis that are designed to be very strong
and resilient to penetration as opposed to being primarily stiffness based. The FIA actually
requires a prescribed composite layer be added to the outermost layer of the side intrusion panel
to increase the intrusion reliance to an acceptable level. The laminate consist of PBO “Zylon”
fibers imbedded in one of two qualified toughed epoxy resin matrices and is of 16ply quasi-

6. isotropic layup, twill weave [5]. Figure 4 show a monococque with the Zylon panels being
impacted by a nose cone.
Fig. 4. Side intrusion and Zylon panels defeating an FIA frontal impact test. [5]
The introduction of composites has significantly improved the crashworthiness and
survivability of racing vehicles. The will always remain an inherent risk to the driver of racing
automobiles because that’s the nature of racing, but these technological advances in material
science help to minimize that risk. The aforementioned discussion pertains to formula 1 and
formula SAE racing, but similar examples can readily be found in other racing circuits. Still,
formula 1 teams are at the forefront of composites research as it applies to vehicle safety and
innovations made there usually find their way to the rest of the automotive racing world. At the
2003 Monaco green prix, Jenson button crashed sideways at 182mph into a tire barrier. The peak
load recorded was 32g and Jenson walked away unscathed [2].
SUSPENSION COMPONENTS
Composites have also made their way into almost every other aspect of the vehicles as
teams continue to strive for weight reduction. Every single suspension component on a formula 1
car has composite materials in some way shape or form. The recent development of thinner
fibers with greater tensile strength and high strength matrix materials has led to the propagation
of composite materials to even the highest stressed components on the vehicle. Composite
suspension components show advantageous durability when compared to the steel parts they’ve
replaced [6]. Advancements in structural adhesives have also helped, as composite parts are

7. often attached to metallic alloys through bonding. Figure 5 shows a formula 1 push rod designed
by Honda racing where titanium ends are bonded to a carbon fiber body.
Fig. 5, Honda RA106 front push rod [6]
In most cases, race car components are of the high complexity low volume variety. Even with
advancements in FEA software and computing power, the complexity of composite components
drives rigorous static and dynamic proof testing of components. Tensile and compression testing
can be carried out on simple two force members like push rods with uniaxial test rigs. Honda
Racing designs to a factor of safety of 1.3 so static test loads are approximately 30% higher then
what is expected in service [6]. For fatigue testing, sinusoidal dynamic loads are applied that
fluctuate between a maximum and minimum load. Some teams have acquired telemetry data for
particular racing circuits and, using multi-axis test rigs, can apply loads to the entire suspension
system that simulate those experienced by the race car for an entire lap. With this technology,
teams can run an excessive number of simulated laps on their vehicles components to verify the
vehicles durability. Often components are tested to failure to expose failure modes. For example,
figure 6 below shows the same push rod in figure 5 after being fatigue tested to failure. The test
showed the local compressive buckling of the carbon fiber close to the metal end was the effect
of bond failure in the joint [6]. Figure 7 shows the peeling failure of the adhesive. The colors
indicating that the disbonding propagated from left to right in the photo.

8. SpeedIncrease vs. Year [7]
Fig. 6. Compression failure of push rod [6] Fig. 7. “Disbond” revealed by UT exam
Composites Effect in Racing Industry
The use of composite materials has drastically changed the landscape of the racing
industry. The cars in the primary circuits of racing—NASCAR and Formula 1—are designed for
different purposes: Formula 1 cars are designed for quick acceleration and unmatched handling,
while the cars in NASCAR are designed for power and intense speed over a long period of time.
When designing the cars, multiple things go into consideration; safety at high speeds,
maintaining high speeds,
maintaining certain handling
characteristics, and cost efficiency
all play a role. The majority of
composite use comes from the
Formula 1 circuit, although
composites do have their uses in
NASCAR. Throughout the past
half century, stock cars have gotten
faster and faster, which leads to
more dangerous crashes due to
such high speeds. The reason
behind the increase in speed is in part due to the decrease in the weights of the vehicles.
Originally, actual stock cars were used in NASCAR, but over the years, actual race cars have
been used, and the bodies have been formed to look like that of an actual stock car. These bodies
are much lighter than the original stock cars, and coupled with more powerful engines, the cars

9. can go much faster. Each of the racecars “starts with a mild steel (1018 or similar) tube-frame
chassis. Titanium alloys or carbon-fiber composites would provide better strength-to-weight
ratios; however, the higher cost led NASCAR to limit chassis materials” [7]. The regulation over
the chassis materials stems from the fact that some of the teams have stronger financial backing
than some others, which would put some teams at a disadvantage at a fundamental level. One
area where composites can be used is a part of the car known as the ‘splitter,’ which provides
down force on the front end of the car. Prior to the introduction of composites on this portion of
the vehicle, the aerodynamics of the front-end was largely uncontrollable. With the introduction
of a material called Tegris, NASCAR finally had a material that met the necessary conditions for
strength and stiffness to develop the front splitter. An important characteristic about Tegris is
that it “does not have a brittle failure mode—it delaminates, so it does not leave sharp pieces for
other cars to run over” [7]. This introduction proved to be cheaper than a carbon-fiber composite,
and it provided safe impact characteristics and improved handling on the cars, which previously
wasn’t as easy to achieve without composites. While NASCAR has developed its uses for
composites, Formula 1 has been the driving force in the advancement of composite use in racing.
Without much of the funding restrictions like NASCAR puts in place, Formula 1 teams are able
to use the funding they receive how they see best fit. [8] In the main introduction of composites
to Formula 1 in the 1950’s, this generally resulted in teams making their chassis out of some
form of glass/polyester resin composite, which was developed during wartime research. This
material provided cheap production for complex curvature bodywork. Carbon fiber composites
hit the scene when the McLaren team in 1980 introduced the first carbon fiber composite chassis.
Many teams were concerned about the strength of the composites under high stress/strain
situations, but after multiple tests, and sometimes accidents on the tracks, the concerns were
disproven. In fact, the composites were shown to behave safer than other materials, minimizing
damage from impacts by localizing the damage to the region of impact—that is, if the impact
wasn’t too strong. From then on, teams tried to find other uses of composites, ranging from
suspension members to gearboxes. Looking back at the introduction of composite materials in
Formula 1, to where it is now, “carbon fiber composites now make up almost 85% of the volume
of a contemporary Formula 1 car whilst accounting for less than 25% of its mass. In addition to
the chassis there is composite bodywork, cooling ducts for the radiators and brakes, front rear
and side crash structures, suspension, gearbox and steering wheel and column” [8]. Due to the

10. decrease in mass because of composites whilst still making up the majority of the volume of the
car, in order to meet regulations, many F1 teams will place ballasts within the car. An
inadvertent consequence, albeit a positive one, of the decrease in mass is that it allows the teams
to alter where the center of gravity on the car is. The upside to this is that it allows the teams to
have greater control over the maneuverability and handling of the car prior to the race. Behind
safety, this is one of the most important aspects of F1 racing, considering many of the tracks
don’t rely on a series of gradual left turns like in NASCAR.
Composites in Commercial Automotive Industry
All of the advances made in racing not only affect racing, but also trickle down into
commercial automotive use. However, the commercial automotive industry has different focuses
on how to use the composites, primarily in safety and weight reduction. While NASCAR and
Formula 1 also focus on weight reduction, they do it for the purpose of being able to go faster
and to manipulate the center of gravities of the cars in order to have better handling. In
commercial use, the purpose of weight reduction is to enhance the fuel economy in
transportation. In the cyclical world of fuel prices, giving customers a car that prolongs the life of
its fuel tank is of extreme importance. Currently, practically all commercial vehicles rely on steel
and other metal alloys for most structural components due to the cost efficiency of their
development. However, the strength to weight ratio of steel and other metal alloys is worse
comparatively to composites. One application in commercial automobile use is in the suspension
of the vehicle, where the “introduction of composite materials made it possible to reduce the
weight of the leaf spring without any reduction on load carrying capacity and stiffness; since the
composite materials have more elastic strain energy storage capacity and high strength-to-weight
ratio as compared to those of steel” [9]. In the figure below, it’s shown that “there is much
weight reduction for composite materials compared to steel. For E Glass Epoxy 88.4%, Graphite
Epoxy 92.4%, Boron Aluminum 90.3%, Carbon Epoxy 92.3%, and Kevlar Epoxy 85.11%
savings in the weight as compared to steel” [9]. These decreases in weight go rather far in terms
of improving fuel economy. Each 10% decrease in total weight of the vehicle results in nearly a
7% increase in fuel economy. Not only does this help the owner of the vehicle in terms of money
spent on fuel, it also helps emissions reduction. For every one kilogram in reduced weight,
there’s a reduction of about 20 kg in carbon dioxide emissions [10]. Another important use for

11. composites in commercial vehicles is the safety. This application has been most influenced by
the advances in racing. The research in crashworthiness that has gone into the use of composites
in the racing industry has provided plenty of information on how composites can be used to
make commercial vehicles safer. In the standard vehicle industry, many of the structural
components are made of standard metals and metal alloys. In an attempt to improve
crashworthiness using these materials, crumple zones have been developed in order to greater
dissipate energy during crashes. However, the failure sequence for composites occurs in a
different fashion compared to metal structures. While metal structures collapse and crumple
under high stress and impact, composites, due to their brittle nature, fail through a in multiple
facets including fibre fracture, matrix crazing and cracking, fibre-matrix de-bonding, de-
lamination and interply separation. The types of failure that occur depend greatly on the
geometry of the structure and the laminate lay up, which can all be used as an advantage if
designed properly. With the right design, composites can be developed for use in high energy
absorption [10]. However, even
with all the advantages that
composites brings to the table,
the cost of the materials and
production have been the main
roadblock in their
implementation in the industry. Compared to conventional metals, the cost can reach up to 10
times the production cost of conventional metals, depending on the composite being produced.
Another roadblock that has prevented composites from becoming a major factor in the
commercial vehicle idnustry is the issue it faces in manufacturability. The composites industry
Material Behaviorvs. Weight [9]

12. has yet to adequately develop methods for high-volume production. Currently, there isn’t a
process that provides cost-effective, rapid, repeatable results while being environmentally
consientious [10]. In the production of the body, although the composites have a better strength
to weight ratio, the cost to production ratio is much worse, as seen in the following figure. When
the total cost of production for a composite structural piece costs at least an extra $1,000 per
vehicle made, it’s clear to see why composites are having trouble gaining traction in the general
automotive industry.
Cost of Production for Different Materials [10]

13. CONCLUSION
The progression of fiber reinforced composites in automotive racing have made the race
cars both faster and safer. These improvements are mainly due to the advantages that fiber
reinforced composites have over metallic materials with regards to their mechanical properties.
Carbon fiber chassis are much stiffer and resistant to intrusion by foreign object while composite
crumple zones absorb energy to lessen g loads on the driver during a crash. Because of the high
cost associated with composite materials composites are not used to nearly the extent in typical
racing circuits like NASCAR as they are in Formula 1. Likewise, composites have enormous
advantageous applications in the commercial automotive industry. They provide safety, as seen
from the racing industry, as well as increased fuel economy due to their lighter weight. However,
due to their high production cost compared to conventional metals used today, composite
application in the commercial auto industry has yet to be heavily implemented.

14. References
[1] Ron Lemasters, Jr, Safety: Racing’s Burning Question, February 1, 2002
http://www.hotrod.com/how-to/interior-electrical/nascar-safety-seat-cockpit-technology/
[2] Savage, Gary, (2004) Exploiting The Fracture Properties of Carbon Fibre Composites to
Design Lightweight Energy Absorbing Structures, Engineering Failure Analysis, vol. 11,
No. 5, pp. 677-694
[3] Jovan Obradovic, Simonetta Boria, Giovanni Belingardi, Lightweight design and crash
analysis of composite frontal impact energy absorbing structures, September 2011
[4] http://www.formula1-dictionary.net/crash_test.html
[5] Savage, Gary, (2010) Development of penetration resistance in the survival cell of a
Formula 1 racing car, Engineering Failure Analysis, vol. 17, pp. 116-127
[6] Savage, Gary,(2009) Sub-critical crack growth in highly stressed Formula 1 race car
composite suspension components, Engineering Failure Analysis, vol. 16, pp. 608-617
[7] Leslie-Pelecky, Diandra, August 2009, Materials at 200 mph: Making NASCAR Faster
and Safer, MRS Bulletin, vol. 34, No. 8
[8] Savage, Gary, July 2008, Composite Materials Technology in Formula 1 Motor Racing,
Honda Racing F1
[9] B Raghu Kamar, R. Vijaya Prakash, N. Ramesh, February 2013, Static analysis of mono
leaf spring with different composite materials, Journal of Mechanical Engineering
Research, Vol. 5(2), pp. 32-37
[10] Elaheh Ghassemieh (2011). Materials in Automotive Application, State of the Art and
Prospects, New Trends and Developments in Automotive Industry, Prof. Marcello
Chiaberge (Ed.), ISBN: 978-953-307-999-8, InTech