Composite Motorcycle Frame
Dave Brimley, Jose Ramirez, North Parker, Dr. Daniel Adams, Dr. K. L. DeVries
Department of Mechanical Engineering
Introduction
As gas prices rise over the years, people will start looking for new
modes of transportation. One of the sectors in the transportation
industry that is expected to grow is the use of motorcycles for urban
transportation. Our proposal to meet the expected increase in demand
is to build a composite motorcycle frame designed for the specific
needs of everyday commuters. By building the frame from carbon
fiber we will not only reduce the weight, but improve the overall
efficiency of the motorcycle while still making it look appealing to the
customer.
Final Prototype
Solutions
Steel Joint Test
Steel tube test yielded favorable results to justify the use of steel joints instead of a
carbon fiber joint construction. After careful calculations a final wall thickness for the
steel tube joints was chosen at 0.07 inches to provide a balance between strength and
light weight construction. The test proved that the welded joint was incredibly strong
and would provide an ample safety factor.
Manufacturing
Requirements
l  Built solely for commuter purposes
l  Designed for loads encountered on a daily commute
l  Ultra-light carbon fiber tube construction
l  Aesthetically pleasing design
First Prototype
Tube and Joint Creation
Test Results
Carbon Fiber Tests
The first prototype consisted of an all carbon fiber construction that
would’ve been ideal but poor joint performance (strength) due to
manufacturing constraints and inconsistencies, a new joint method
had to be devised to meet the strength requirements of the joint.
Advanced Composites, Inc. (ACI) was incredibly generous, donating carbon fiber
material and the use of their equipment and facility. We were able to fabricate the
carbon fiber tubes on their CNC filament winding machine. This ensured consistent
tube properties. They allowed us to use other machines in the shop to machine and
cut the tubing for the mitered joints. Coped and mitered joints were constructed at
different angles and configurations to match each required joint in the frame design.
The tubes and steel joints are joined together using a high temperature adhesive with
a high strength that provides a joint separation strength that is greater than the yield of
either the steel or carbon tube by itself.
Alignment and Construction
Testing
There were several tests conducted to compare the performance of
the prototypes related to the predicted metrics defined using Finite
Element Analysis (FEA) and ideal manufacturing.
A frame alignment jig was
fabricated to ensure the
fitment of the donor
motorcycle components.
Steel Joint Test
Conclusion
Tests were performed on the carbon fiber joint and the steel joints
using an Instron testing machine to acquire strength properties from
these joints
l  Mass production of a frame comparable to ours would require extensive research,
testing and a large investment.
l  Molds and other methods for joining tubes together would have to be developed to
ensure an accurate and consistent bonding between parts.
l  Due to our time constraints and available resources we had to build the frame using
steel joints that complemented our carbon fiber tubes.
l  Only one frame was produced and no further materials testing was performed.
l  Composite frame weight: 14.2 lbs
l  OEM Kawasaki donor frame: 28.0 lbs
l  49.3% weight reduction
Problems
ACKNOWLEDGEMENTS
l  Hand made tubes took a substantial amount of time to manufacture.
l  Heat tape pressure was inconsistent around the joints and thus led
to voids and material inconsistencies.
l  Heat tape was difficult to release and had to be ground off of tubes.
l  Advanced Composites, Inc.
l  The Kitten Factory
l  Dr. Daniel Adams
l  Dr. K. L. DeVries