1. Composite Layup of a Model for 2016-2017 CSU
Northridge Human Powered Vehicle Fairing
California State University, Northridge
College of Engineering and Computer Science
ME 436L: Mechanics and Design of Composite Materials Lab
Dr. Peter Bishay
Team Members:
Cassandra Mathison
Mike Prusmack
Due Date: 12/11/2016
Submission Date: 12/11/16

2. 2
Table of Contents
Cover Page Pg. 1
Table of Contents Pg. 2
Abstract Pg. 3
SolidWorks Development Pg. 3
Layup Process Pg. 5
Post- Processing Pg. 9
Concluding Remarks Pg. 10

3. 3
I. Abstract
Composite materials are becoming a regular aspect for all engineering designs and
disciplines. They’re known for their ability to take the desired traits of more than one material.
At California State University, Northridge the class ME 436: Mechanics and Design of
Composite Materials is an undergraduate class which studies the macromechanics of various
laminate composite materials. Machromechanics consists of the study of composite material
behavior where it is presumed that the material is homogenous and the effects of the constituent
materials are only detected as averaged apparent macroscopic properties of the composite
material. The design choice came from one of the seven ideas that the 2016-2017 Human
Powered Vehicle team generated for their fairing. The fairing is usually constructed out of two
layers of carbon fiber with an epoxy matrix for CSUN’s team, but the material choice is
completely optional. Fiber-reinforced laminate composite materials of any kind are generally
chosen due to their high strength-to-weight ratios. The selected material for this project was
fiberglass. This final project was completed in order to demonstrate the skills and knowledge
gained during both the lecture and lab portions of this class.
II. SolidWorks Development
The final project was to consist of a scaled down version of a design for structures that
would typically utilize composite materials. Some teams did airfoils, whereas others did fairings.
This paper in particular will cover the development and manufacturing of a miniature version of
one of the initial designs for the CSU Northridge 2016 - 2017 Human Powered Vehicle Team
fairing. An option for this competition is to encapsulate the vehicle with either a full, partial, or
no fairing. The fairing that was to be modeled for this project was chosen as one of the possible
final designs due to the results gathered in the computational fluid dynamics analysis completed
in SolidWorks The purpose of this project was to complete a wet layup, using fiberglass,
fiberglass of one of the possible fairing options. The fairing was scaled down to 1/7 of its
original size. The project encompasses every major part of the manufacturing process from the
SolidWorks model to the completed physical part. The end goal was for students to gain hands-
on experience in the major aspects of handling composite materials.
The fairing design that was utilized was generated using SolidWorks 2016 software. The
CSUN 2016-2017 Human Powered Vehicle Fairing Team was responsible for conceptualizing
the design and then bringing it to life on the computer. It was constructed as a shell using profile
outline guides along with spaced cross-sections longitudinally to create a surface. The design of
the fairing also had to take into consideration clearances for both the rider of the vehicle as well
as the components and the frame. The selected design choice can be seen in Figure 1.

4. 4
Figure 1: Initial fairing part to be created
Once the design was completed, a negative of the fairing had to be created so the block
that was to be used could have the desired shape cut out of it. When generating the block part
file, a fair portion had to remain on the outside of it so the layup could have a lip lying about 1
inch around the edge of the fairing. The block and the fairing parts were mated in an assembly so
that the mid-plane of the fairing lined up with a face of the block. The cavity tool in SolidWorks
was then used to create the female potion that was desired. This new part carried the code that
would be needed to manufacture the physical part with the router. Views of this part can be seen
in Figure 2 and Figure 3.
Figure 2: Perpendicular view of fairing negative
Figure 3: Isometric view of fairing negative

5. 5
IV. Layup Process
The layup process can take several minutes up to several hours, depending on the size of
tool being used and the type of layup being done. The actual length of the 2015-2015 Human
Powered Vehicle fairing was just under 100 inches. Therefore, a significant amount of time and
hands were needed in order to successfully complete the entire fairing. Fortunately, a scaled
down mold was used and made it so the layup could be completed in less than two hours.
The scaled down mold was created with foam and a machining process that mirrored that
of the SolidWorks part file. Once the mold was obtained, it needed to be sanded by hand to
ensure a smooth finish for the actual composite and to reduce areas of imperfections. Once the
tool was prepared, the layup could begin.
The layup that was completed was a wet layup rather than a layup with prepregs. A wet
layup is a more elaborate process and is made up of several steps. The first thing that needed to
be done was obtaining all of the necessary supplies. The hard materials included: the tool, sheets
of fiberglass, bagging material, breather fabric, scissors, mixing cups, release film, a scale,
mixing sticks, gloves, vacuum sealant tape, and microfiber cloths. The liquid materials included:
acetone, epoxy resin, release wax, release agents. The pieces of the cut fiberglass, vacuum
bagging, breather fabric, and release film were cut to fit specifically to the tool being used. They
can all be seen in Figure 4. Next, the tool needs to be properly cleaned with the acetone. Acetone
is applied to a clean microfiber cloth, and the rag was used to wipe down the inside and outer
edges of the mold. This can be seen in Figure 5.
Figure 4: The cut pieces of fiberglass,
vacuum bagging, breather fabric, and release
film
Figure 5: Surface of tool is cleaned
with acetone

6. 6
Following that, vacuum tape was applied around the edges of the layup. The purpose of
the tape is to allow the vacuum bag to be attached to the surface and to help rid the bag of any
possible air leaks. It is best to apply it early (and to leave the wax paper on) to ensure other
chemicals won’t interfere with its adhesive ability. This can be seen in Figure 6. After the
application of the tape, mold wax was applied in five separate layers, as seen in Figure 7.
Figure 6: Vacuum tape is applied to the
perimeter of the layup
Figure 7: Mold wax being applied to
the tool
The release agent was then applied. There are two steps to this process. TR-910 is used as
the main coat which will seal the mold’s surface. Using a new cloth, ten layers were applied with
time to dry between each application. This can be seen in Figure 8. After all ten layers were
applied and dried, TR-930 was then applied in five layers, as shown in Figure 9.
Figure 8: Application of TR-910 Figure 9: Drying of TR-930

7. 7
Finally, the actual layup began. Three separate cups were used to mix the epoxy resin and
the epoxy cure together. Using the scale, 100 grams of the epoxy resin was poured into the first
cup and then set aside. This is shown in Figure 10. Then, 27 grams of the epoxy cure was poured
into the second cup and set aside. This is shown in Figure 8. When ready, the two were poured
into the third cup and mixed together with a mixing stick. A clock was started simultaneously for
once the two chemicals meet their pot life begins and is limited to one hour.
Figure 10: Measured epoxy resin Figure 11: Measured epoxy cure
Once it was thoroughly mixed, the resin/cure compound was applied in a thick layer with
a brush to the tool on the parts where the fiberglass was going to be placed. Then, the first layer
of fibers was placed on top of the too, as seen in Figure 12. The cloth was pressed and the resin
compound was spread using just glove-covered hands. After the fiberglass was evenly placed on
the mold, and the resin compound was evenly distributed, more of the resin compound was
added, and another sheet of fiberglass was placed on top. This was done a total of four times.
The final wet layup is shown in Figure 13.
Figure 12: First layer of fibers on top
of resin covered tool
Figure 13: Completed wet layup

8. 8
The perforated release film was then placed evenly on top of the the layup. The holes
allow the excess resin to escape into the the breather cloth. The breather cloth was then placed on
top of the release film. These steps are shown in Figures 14 and 15, respectively.
Figure 14: Perforated release film on
top of layup
Figure 15: Breather cloth on top of
perforated release film
The vacuum connection was placed on top of the breather cloth on a flat location that
wouldn’t disturb the structure. The wax paper is then removed from the vacuum tape. The
vacuum bagging is placed across the tool and attached to the vacuum tape. This can be seen in
Figure 16. Several pleats were included due to the excess bagging. Then, an opening is cut into
the bagging at the same location as the vacuum connection. The pleats can be seen in Figure 17.
Figure 16: Vacuum bagging and
connection readied
Figure 17: Bagging applied to the tool
with pleats

9. 9
Unfortunately, the first time that this was done, there were leaks within the tape and the
bagging that could not be found nor corrected. Alas, the edges had to be cleaned, re-taped, and a
new piece of bagging had to be cut. Finally, the vacuum is attached and the drying process can
begin.
Figure 18: Final bagging setup with attached vacuum
V. Post-Processing
The fiberglass layup spent at least 24 hours curing and once it was ready, it was removed
from its tool. There were slight imperfections inside of the final model due to the wrinkles in the
bagging. Any exterior flaws would have been caused by faults of the tool. A laser cutter was
used to remove the excess material around the edges, and then was handed off to a Master’s
composites class for analysis. The final product can be seen in Figure 19.
Figure 19: Completely cured model of fairing

10. 10
VI. Concluding Remarks
The focus of this project was one of the seven possible designs for CSUN’s Human
Powered Vehicle fairing. The purpose of the fairing is to reduce drag on the entire vehicle and
consequently increase its top speed. SolidWorks was the software of choice for both the
development of the fairing as well as the negative of the fairing. Fiberglass was the material of
choice for this particular project, but the Human Powered Vehicle team will instead be using two
layers of carbon fiber.