Momentum - April 2019 - 9

As the concept evolved-achieving overall wins at
Formula Student UK in 2003, 2005, and 2006-it spread
to other areas of the chassis. By 2007, composite panels
had taken over much of the structure forward of the
front roll hoop. Balsa wood core was used in place of the
nomex honeycomb to provide local stiffness around the
bellcrank and damper mounts, which continued to take
advantage of the thick, rules-mandated steel tubes by
loading the front roll hoop.
It worked. The 2007 chassis featured an 8% deviation
between its simulated and physically tested torsional
stiffness numbers, and boasted the lowest assembled
weight of any UTFR chassis to date. Retaining the
winning powertrain package from previous years, UT07
achieved a 5th place overall finish at Formula Student UK.
As the concept evolved, the team continued to replace
steel tubes with composite panels. With so few of these
tubes remaining forward of the main roll hoop on UT07,
that meant constructing a full monocoque for UT08.
Despite ongoing development, performance suffered.
The first full monocoque, manufactured for the 2008
season, was much heavier than its predecessors, due
to inefficiencies in manufacturing. This period of the
team's history also featured a concept change to a
single-cylinder engine in an effort to offset the weight
of the heavier monocoque. By 2009, the best result of
the season was a 35th-place overall finish at Formula
SAE Michigan. Despite the phenomenal global stiffness
exhibited by the full-length monocoque (in excess of
5000 Nm/deg), local stiffness in the suspension load
paths compromised its effective stiffness. Physical
torsion tests on UT09's chassis indicated that it was
only providing 24% of the torsional stiffness that
the simulations indicated it would, and as a result,
suspension adjustments could not adequately tune the
car's handling.
The only option for 2010 was to strengthen the
monocoque by adding additional material to the
layup, further increasing its weight. The design report
from the following year explains: "The UT10 vehicle
achieved adequate local stiffness values, at the cost of
an overbuilt chassis with respect to torsional loading
(7000 Nm/deg simulated, 2850 Nm/deg hub-to-hub)
and a poor stiffness/mass ratio in comparison to other
competitive chassis."
After a difficult transitional period in 2011, the team
prioritized the ease of manufacturing a traditional space
frame over the complexity of a monocoque. Suspension
mounting was once again optimized to take advantage
of the steel members-which are more easily simulated
than the composite mounts-and the wheelbase was
shortened. UT11's chassis achieved a much better
stiffness-to-weight ratio than its predecessors.
After several years of optimizing the full space frame
concept, improving the stiffness-to-weight ratio on
each iteration, an ambitious chassis designer revived
the hybrid concept for the 2016 season. The new
design was influenced heavily by its history. This time


UT17, shortly after bonding the carbon composite side panels to this secondgeneration hybrid chassis concept.

Steel tube frame

Composite panels added

Chassis diagrams from Margaret Lafreniere's BASc Thesis on the 2007 chassis design,
analysis, and manufacturing.

however, the composite side panels took structural credit for all of
the rules-mandated side impact protection. This second-generation
hybrid concept saved 6 kg over its spaceframe predecessor. Refined
suspension mounting improved its efficiency by shortening the loaded
portion of the chassis, and loading the shortened midriff in compression
rather than torsion. Tested stiffness numbers on our modern hybrids
have returned to within 10% of simulated values, allowing for much
lighter construction and consistent suspension tuning.
We're proud of the awards that hang on our walls, and every day we
stand on the shoulders of the team members who came before us. Our
goal in the coming seasons is to ensure that we do their legacy justice,
and we're excited to continue to build on their validated learning to
achieve the best results we can.
This article was written for MOMENTUM by Jonathan Libby, a third-year
computer science student at the University of Toronto. He serves as a
driver and Business Lead for the University of Toronto Formula Racing

April 2019 9


Momentum - April 2019

Table of Contents for the Digital Edition of Momentum - April 2019

Momentum - April 2019
Reliability overhaul: a lesson in resilience
Turbulence on the track
Full circle
Lap simulation tool shows the way
Baja SAE technical inspection
VW’s MEB platform: a modularity enabler
The F-22 Raptor gets its first metallic 3D-printed part
SAE 101: WCX 2019
Moon shot as metaphor for autonomous vehicle technology
DOSSIER: Greg Sawvelle
Momentum - April 2019 - Momentum - April 2019
Momentum - April 2019 - Cover2
Momentum - April 2019 - Contents
Momentum - April 2019 - A better MOMENTUM
Momentum - April 2019 - Briefs
Momentum - April 2019 - Reliability overhaul: a lesson in resilience
Momentum - April 2019 - 5
Momentum - April 2019 - Turbulence on the track
Momentum - April 2019 - 7
Momentum - April 2019 - Full circle
Momentum - April 2019 - 9
Momentum - April 2019 - Lap simulation tool shows the way
Momentum - April 2019 - 11
Momentum - April 2019 - Baja SAE technical inspection
Momentum - April 2019 - VW’s MEB platform: a modularity enabler
Momentum - April 2019 - The F-22 Raptor gets its first metallic 3D-printed part
Momentum - April 2019 - SAE 101: WCX 2019
Momentum - April 2019 - Moon shot as metaphor for autonomous vehicle technology
Momentum - April 2019 - 17
Momentum - April 2019 - DOSSIER: Greg Sawvelle
Momentum - April 2019 - 19
Momentum - April 2019 - 20
Momentum - April 2019 - Cover3
Momentum - April 2019 - Cover4