Overcoming the Challenges of Composite Design through Simulation
Keywords: Vehicle Development, Composite Materials
Composite materials have been used
in the aerospace industry for many
years due to their lightweight and high
performance characteristics, but the issue
of product weight is not limited to aircraft.
Automotive manufacturers are increasingly
viewing the material as a method of
minimizing mass and maximizing fuel
economy.
The material is not without its design
challenges. Composite ply layer stacking
order and fiber direction creates a huge
number of design variables to take into
account when simulating complex events
such as crash. Furthermore, the inherent
high cost of the material can lead many to
see composites as the reserve of high-end
sports vehicles.
UK based automotive design company,
Gordon Murray Design (GMD) believes
that composite materials can play a much
larger role in the manufacture of vehicles
and to prove its case, the company has
developed 'iStream', an efficient process for
manufacturing low and high volume cars
from lightweight mixed materials.
The iStream process seeks to reduce
all costs associated with developing a
vehicle, from factory development and
assembly to tooling design and end of life.
Whereas the traditional approach to vehicle
manufacturing sees stamped steels used for
the body structure, GMD's innovative iStream
manufacturing process uses lightweight
composite panels bonded to a tubular
metallic frame.
IndustryAutomotive
ChallengeComposite material modeling for a innovative new vehicle platform
Altair SolutionExtensive use of simulation technology to understand the behavior of the material under crash loads
Benefits•Accurate simulation of composites•Lighter, fuel efficient vehicles
Key Highlights
Success Story
“Working directly with the Altair ProductDesign team and how they integrate and interact with Altair’s software division and all the other components of the organization has been invaluable to us."
Simon Maher, Senior Stress & Materials Engineer, Gordon Murray Design
iStream is being developed as an intellectual
property for GMD which it intends to license
out to companies wishing to diversify into
the car market. However, in order to make
iStream successful, GMD must prove that
a vehicle which relies on composite panels
for much of its structural integrity can meet
strict performance targets. To do this, GMD
has developed a number of demonstrator
vehicles including the T.25 and T.27 that
utilize the iStream philosophy.
Selecting an Experienced Simulation Development PartnerGMD is a small, focused and highly talented
company with a huge amount of vehicle
engineering pedigree and experience.
The iStream project requires a deep
understanding of the behavior of composite
material and how it can be accurately
modeled to prove its suitability as a
structural component.
GMD is an established user of Altair's
HyperWorks suite of simulation technologies.
When the company was looking for an
external partner with simulation expertise,
Altair ProductDesign, was
the natural choice. Altair
is able to link its software
development business
with its engineering
services, allowing Altair
ProductDesign to apply
experiences gained during projects to
directly influence the functionality and
accuracy of the software suite. This was a
key decision factor for GMD who saw the
interaction between the two businesses as
a crucial differentiating factor over other
product development companies.
Streamlined Model BuildAltair ProductDesign was asked to improve
the virtual modeling of the composite
materials used in iStream to achieve
correlation with physical
test results.
The first task was to build
accurate material models
for the iStream sandwich
panels. The panels are
considerably lighter than metal alternatives
while maintaining strength and stiffness as
well as being inexpensive to maintain and
avoid many corrosion issues.
The T.25 Demonstrator Vehicle Showing the iStream Frame
T.27 Utilizes iSteam to Create a Lightweight Electric Drive Vehicle
Altair ProductDesign was asked to improve the virtual modeling of the composite
materials to achieve correlation with physical
test results
To effectively model the structure requires
detailed modeling of the glass fiber
laminates, soft core and the structural
adhesive used to bond the panels to the
frame. GMD tasked Altair ProductDesign
with creating a highly tuneable CAE model
of an iStream chassis in order to appraise
the load paths in frontal and side dynamic
impacts. Using Altair's HyperWorks suite,
Altair ProductDesign suggested a finite
element modeling method which utilized 1D
beam and shell elements
for different parts of the
vehicle structure with much
of the model creation
work conducted by Altair's
offshore capability to speed
up this time consuming phase.
This method allowed the analysis stage to
directly inform the design stage through the
creation of representative virtual models
of the composite material developed much
earlier than in a standard development
process. Design direction could be quickly
explored, manipulated and assessed but
without creating compute intensive analyses.
Accelerating the analysis process enables
GMD to rapidly investigate more design
variations and achieve the optimal design
configuration in a shorter timescale.
Defining Material BehaviorUnderstanding the behavior of the
composite materials is a crucial step in the
development cycle as the level of knowledge
within the automotive industry is not as
mature as with metallics.
Once a level of confidence
in the material behavior
at a component level is
achieved, the material
simulation will move
beyond discrete components and onto a
system characterization level. Here, sub
and full systems are analyzed, allowing the
engineers to view the interaction of each
part on the surrounding components during
loading.
Altair ProductDesign and GMD will carry
out a range of virtual simulation tests using
HyperWorks' RADIOSS solver to define
the material's behavior under various
loading conditions including crash. The
virtual testing process is performed with
an understanding of the physical test
requirements to ensure that results can be
effectively correlated without the need to
repeat tests unnecessarily.
Conclusion: Developing Innovative Vehicles with Added ConfidenceAs the analysis and correlation to physical
test stages of the project become finalized,
Altair ProductDesign will continue to
work with GMD and develop the iStream
structure to improve crash performance.
The use of advanced materials require
innovative methods of design and validation
to ensure that they perform at the highest
levels without compromise to safety. The
combination of simulation expertise from
Altair ProductDesign and the vehicle
development and composite expertise of
GMD has been a highly effective partnership
that will help to prove the value of the
innovative iStream process.
Gordon Murray Design was established in 2007 in the UK to develop an innovative and disruptive automotive manufacturing technology trademarked iStream, the design and prototyping of the T.25 City Car was central to the validation and development of iStream.
About Gordon Murray Design
Comparing Virtual Crash Model with Physical Test of the iStream based T.32 Nose Cone
Altair ProductDesign will continue to work closely
with GMD and develop the iStream structure to improve
crash performance
Find out more about Gordon Murray Design: www.gordonmurraydesign.com
Find out more about Altair ProductDesign:www.altairproductdesign.com
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Success Stories
Altair empowers client innovation and decision-making through technology that optimizes the analysis, management and visualization of business and engineering information. Privately held with more than 1,800 employees, Altair has offices throughout North America, South America, Europe and Asia/Pacific. With a 25-year-plus track record for innovative product design and development, advanced engineering software and grid computing technologies, Altair has more than 3,500 corporate clients representing the automotive, aerospace, government and defense, and consumer products verticals. Altair also has a growing client presence in the life sciences, financial services and energy markets.
Altair ProductDesign is a global, multi-disciplinary product development consultancy of more than 700 designers, engineers, scientists, and creative thinkers. As a wholly owned subsidiary of Altair Engineering Inc., this organization is best known for its market leadership in combining its engineering expertise with computer aided engineering (CAE) technology to deliver innovation and automate processes. Altair ProductDesign firmly advocates a user-centered, team-based design approach, and utilizes proprietary simulation and optimization technologies (such as Altair HyperWorks) to help clients bring innovative, profitable products to market on a tighter, more efficient time-scale.
HyperWorks is an enterprise simulation solution for rapid design exploration and decision-making. As one of the most comprehensive, open-architecture CAE solutions in the industry, HyperWorks includes best-in-class modeling, analysis, visualization and data management solutions for linear, nonlinear, structural optimization, fluid-structure interaction, and multi-body dynamics applications.
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