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FEMAP SYMPOSIUM 2014
Discover New Insights Femap Symposium 2014
May 14-16, Atlanta, GA, USA
Simulation of laminate composite
space antenna structures
Sairam Prabhakar
2014-05-15
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Agenda
• Background
• Workflows for modeling composite antenna structures
• FEMPLY to pre-process composite structures
• Post-processing laminate composite structural analysis with FEMPLY
• SA Toolkit for rapid random response analysis
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Laminate composites for space structures
• Why Composites:
• Lighter
• $10,000 - $100,000 to put a pound of
payload into orbit
• 20% lighter than Aluminum
• Stiffer
• Directional stiffness which can be tailored
• High modulus Carbon fibers – 350 GPa
• Thermally Stable
• Can design zero Thermal Conductivity
Radarsat1
Source: Wikipedia
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Next Generation Composites: MDA Medium-Sized
Reflector
• Medium (0.9 m dia) reflector developed by MDA
Corp and Composites Atlantic
• One of the early composites reflectors: light, stiff
and exceptional thermal stability
• Technology now used by ESA Sentinel satellite
program, Intelsat, and Boeing
• Significant profitability:
• Original development funded by Canadian
Space Agency grant of $939,000
• Revenue generation of ~ $5 Million annually for
MDA Corp
Source: MDA Corp
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Introduction to MAYA
MAYA Simulation is a developer of leading-edge software
packages for a variety of engineering applications
Thermal, CFD, structural, laminates, NVH, durability
Strategic Partner of Siemens PLM Software
OEM provider of software products and components since 1986
VAR in North America, specializing in CAE
105 employees
75 technical staff, 24 Ph.D’s
Extensive experience in CAE consulting using SPLM tools
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MAYA Simulation Technologies
• Over 2 decades of structural analysis experience:
specifically in composite satellite structures
• Structural customers include MDA, Bristol Aerospace,
Composites Atlantic,….
• Recent successes: RADARSAT and CASSIOPE
• FEMAP and NX for Pre/Post. NX Nastran for solving
Source: CSA
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Key steps in structural analysis of composites
• Defining layup:
• “Global” ply definitions
• “Drop-off” definitions
• As-manufactured fiber orientations:
• Draping simulation
• Orientation-consistent NASTRAN PCOMPs
• Ply-wise results processing
• User-defined failure indices from NASTRAN
computed stress/strain results
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FEMPLY is a Composite Ply-Based Modelling tool fully integrated
into Siemens’ FEMAP Pre/Post-processor offering fast, efficient
and simple definition of complex component layups.
FEMPLY Pro extends the
functionality by adding:
• Ply Draping
• Flat Pattern Export
• Laminate Failure Calculations
• Sandwich Stability
Calculations
• Failure Envelope Charting
What is FEMPLY
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What is Ply-based Modeling
Layup Based Modelling Ply Based Modelling
User Defines Layups
/ Properties
User Applies
Properties to Parts of
the Model
User Defines Ply
Extents
Layups / Properties
Automatically Created
and Properties Applied
to Parts of the Model
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Why Perform Ply-Based Modeling?
Layup Based
Modelling
Ply Based
Modelling
No. of Plies to define. 4* 4
No. of Layups to define. 7 1
No. of Properties to define. 7 -
Total User Inputs. 4*+7+7=18 5
*If Post-processing using global ply IDs is required
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Key Features: Simple Ply Definition
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Key Features: Remapping plies on Remeshing
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Key Features: Ply Draping
Ply Interior holes are handled
Draping results can be used to apply properties with modified fibre
angle.
Export draped patterns to DXF
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Key Features: Advanced Post
Layered Results as well
as Critical Ply and Fibre
Angle Output Vectors are
created.
• Max Stress/Strain
• Tsai-Wu
• Hill
• Hoffman
• Puck
• LaRC02
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Key Features: Post-processing sandwich panels
• Skin Wrinkling
• Shear Crimping
• Honeycomb Dimpling
Critical Direction and
Face Output Vectors are
created.
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Key Features: User Defined Failure Theories
• No Programming Skills
Needed.
• Ply stresses, strains
and moduli available as
variables
• Multiple Conditions
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Key Features: Reporting
• Plot Ply Failure Envelopes
• Export Bill of Material and
Layup data to MS Word
• Export Laminate and
Sandwich Failure calculations
to MS Word
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Structural Analysis Toolkit (SA Toolkit) for NASTRAN
• Efficient and accurate random and sine solutions from NASTRAN normal modes results
• Efficient post-processing of Nastran results
• Ranking, sorting, enveloping, filtering
• Summaries by groups, subcases, etc.
• Margins of safety for different failure types
• Direct manipulation of .op2 file data
• Extremely efficient for large models
• Support NX, MSC Nastran
• Windows & Linux
• Automatic Report Generation
• HTML, MS Excel®, ASCII
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SA Toolkit Suite
Random vibration processor
Sine vibration processor
Modal processor
Energy processor
Mass processor
Stress processor
Grid point force processor
Element force processor
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SA Toolkit Random Processor
SAToolkit Random Processor
• Statistics are required to assess the probability of the response’s
magnitude
Source: Wikipedia
• Random theory assumes
that the input follows a
Gaussian distribution.
• The same assumption
applies to the response
2
2
2
2
1)(
x
exp
20
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SA Toolkit Random Processor
Examples of response quantities that do not follow Gaussian distributions
• Von Mises stress
Source: Wikipedia
21
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SA Toolkit Random Processor
Examples of response quantities that do not follow Gaussian distributions
• Tsai-Wu composite failure index
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Evaluation of non-Gaussian responses
• To evaluate response quantities that do not follow Gaussian distributions, numerical approximations are required:
• Segalman or Fast approximation method for Von Mises stress
• Also need to validate the approximation using Monte Carlo simulation
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Peak Results
True peak stresses and failure metrics based
on a probability level that is either:
• Directly specified, OR
• Equivalent to a Gaussian pdf with specified
standard deviation • eg 99.73% = 3 sigma
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Efficient and Accurate Interpolation
Uses NX Nastran eigenvectors from a SOL 103 run
• High-performance integration algorithm
• Does not require frequency card (FREQ) definition
• Avoids the risk of error by under-specification of number of computation
frequencies
• Only need to supply the minimum and maximum frequency bounds for the
simulation
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High Performance Solver
Composite tube model benchmark
• 29,000 solid elements
• 60 plies defined on PCOMPS card
• SOL 103 .op2 file size: 1.82 GB
• Stress request: Bottom/middle/top
• Peak ply stress extraction: 58 secs
• Peak max stress failure index extraction: 1 min 12 secs
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Random Ply Results
• Elemental • Ply stresses, strains
• Homogeneous stresses and strains, Von Mises stresses
• Shell resultants, 1D and 3D element forces
• Nodal • Acceleration, displacement, velocity, grid point force, mpc
force, spc force
• Relative or absolute displacements,
velocities and accelerations
• Number of positive crossings
• All entities or selected groups
22 ( )( )1 1
02 2
( )
UU
LL
U
L
S dS d
NRMS
S d
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Compensation for Modal Truncation
Modal Truncation Effects
• Account for modal truncation effects via either:
• Residual vectors via the NX Nastran RESVEC Case Control request, or
• Residual flexibility approach via the supplied DMAP
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Conclusions
• FEMAP is an effective pre/post environment for laminate composite antenna
structure analysis
• FEMPLY provides enhanced workflows for composites structural analysis:
• Global ply based modeling
• Ply draping simulation
• Efficient results processing
• Complete set of polynomial and advanced failure theories
• User-defined failure theories
• SA Toolkit provides a fast and powerful tool for random response analysis
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Contact
Sairam Prabhakar
Senior Technical Specialist
MAYA Simulation
4999 St. Catherine West
Montreal, QC, H3Z 1T3
Phone:
Fax: (514) 369-5706
Mobile: (514) 690-7247
E-mail: