JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 56

simulation

Fig. 4: Composite laminate visualization with
overlay of ply-layer angles

fatigue, and water absorption. Also, the
damage can occur in non-intuitive ways.
For example, delamination - which is
defined as the separation of laminate
layers - can occur when the loading is
not perpendicular to the layers. Also,
thermal fatigue can occur without any
mechanical load applied. Understanding
these failure modes and how they occur
is required in the design of composite
structures and additional education is
needed by the designers of these structures. A good designer with metals cannot transition over to designing composite structures and be successful without
additional knowledge and training.
Most of the available analysis methods
are based on analysing the composite
component as a uniform material with
anisotropic material properties. This allows the component to be analysed efficiently for the stress-strain and displacement response. On the other hand, the
failure of composites generally occurs
at the fibre/particulate and matrix level
which is not modelled with traditional
analysis. Modelling at this level would
quickly overwhelm the computer and
take significant time to solve. As a result
of the current modelling methods, the
common failure models used with composites only derive their inputs from the
macro-level models that are performed
and are very conservative in nature. This
produces safe components that perform
their function but in most cases, components are overdesigned.
Over the last several years, techniques
have emerged from universities and

research labs that help to analyse
composites at the fibre-matrix level
without adding significant time to the
analysis process. These micromechanical
analysis tools break down the composite
response into constituent responses for
stress and strain. They can then predict
the onset of matrix cracking or fibre
breakage, which is the precursor to more
catastrophic damage. Many of these
tools are now commercially available
and are allowing companies to further
reduce the weight of their components
by having more accurate damage models. [1-3]

used for Indy Car racing for years and
top teams have used simulation and optimization tools to improve the speed and
performance of the vehicles that provide
maximum protection for drivers. A
key part of this analysis is to make sure
the composite impact zones dissipate
the energy from the crash in a predictable fashion. Being able to analyse the
composite structure and "see into" the
structure to see how the damage initiates
and propagates has been invaluable in
understanding how to best design these
structures to absorb as much energy as
possible during a crash. [4]

Impact analysis

Models can predict damage progression, even at very small time scales,
they can differentiate between different
failure modes, and can handle the many
variables involved in characterizing a
composite structure. With an accurate
damage model, many different design
parameters can be analysed, such as
laminate lay-up, fibre volume fraction,
and different combinations of fibre and
matrix materials. With this ability, the
best materials and designs can be chosen
for specific structural applications. n

Understanding the impact performance
of composite structures is important as
these materials find their way into new
products and applications. Composites
behave far differently under impact
than metals since they are made up of
primarily brittle materials. Whereas metals deform and yield, composites tend
to fracture. In many cases, the damage
from impact occurs beneath the surface,
making damage difficult to detect visually. Composite damage mechanisms are
also varied and can include delamination, fibre breakage, matrix failure or
a combination of all of these. Damage
progression is difficult to measure, even
in laboratory settings, since the damage
occurs internally and can progress very
fast.
Much progress in crash analysis of composite structures has come from the auto
racing circuit. Composites have been

Fig. 5: Bird strike analysis with RADIOSS including
failure and delaminating theories.

56 jec composites magazine / No94 January - February 2015

More information:
www.altair.com
References
[1] Wollschlager, J.A., and Yancey,
R.N., "The Integration of Composite
Constituent-Level Failure Models During
Composite Size Optimization", SAMPE
Tech 2012, Charleston, SC.
[2] Yancey, R.N., Mestres, E., Mouillet,
J-B., Asaker, R., Jeunechamps, P-P.,
Boisot, G., and Gerard, J-S., "Simulating
Impact Performance of Composites",
SAMPE 2011, Long Beach, CA.
[3] Stefanovic, M., Yancey, R.N., Gies, J.,
and Hill, D., "Simulation Driven Weight
Optimization of a Composite UAV Spar
Using Multiscale Analysis", SAMPE 2010,
Seattle, WA.
[4] Pignacca, L., "Simulation: The
Connection between Speed and Safety in
Racing", Concept to Reality, Summer/Fall
2012, Penton Media, Inc., c2r.altair.com.


http://www.altair.com http://c2r.altair.com

JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015

Cover
Edito
Point of view: Raw materials
Contents
Companies & Business
In brief
Resins - lnterview
Agenda of Events
Applications
Aerospace
Defense
Sustainability
Market
Overview 2014
China - Interview
FEATURE CARBON
Carbon
Training
Investment - Interview
Simulation
CFRT
Nano
Equipment
Marine
Research & Development
Monitoring
LCM
Technology & Innovations
Manufacturing
Pultrusion
NDT
Matrix
Simulation
Index
In the world
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Cover
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 2
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Edito
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Point of view: Raw materials
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 5
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Contents
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 7
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - In brief
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 9
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 10
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Resins - lnterview
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 12
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 13
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 14
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Agenda of Events
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Ad1
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Ad2
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Aerospace
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 17
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Defense
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Sustainability
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Overview 2014
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 21
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - China - Interview
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 23
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Carbon
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 25
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Training
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Investment - Interview
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 28
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Simulation
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 30
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 31
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - CFRT
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 33
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Nano
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 35
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 36
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Equipment
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Marine
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 39
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Monitoring
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 41
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 42
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - LCM
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 44
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 45
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Manufacturing
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 47
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Pultrusion
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 49
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - NDT
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Matrix
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 52
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 53
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Simulation
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 55
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 56
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - Index
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - In the world
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 59
JEC COMPOSITES MAGAZINE - Issue #94 - January/February 2015 - 60
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