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Interface Software Development for Patran/Thermal, Esarad and Thermica
19th European Workshop an Thermal and ECLS Software
Dr. Cosmas Heller
EADS ASTRIUM GmbH, Friedrichshafen - Germany
All the space you need
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Contents
I. The Goal for Thermal Distortion
II. Current Status
III. Thermal Distortion Work Flow
IV. First Interface Approaches
V. Second Interface Approach
VI. Summary
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I. The Goal for Thermal Distortion
Approach for an “ Ideal” Thermal Distortion Process:
� GMM creation with the aid of the CAD and FEM mesh data
� Ray tracing, flexible and reliable orbit analysis
� Semi/Fully-automated capacity and conductor calculation
� Direct creation of TMM (skeleton file) with user coding
� Post-processing (incl. stochastic tool) to identify worst cases
� Transfer of geometry and worst case temperatures
� Automated temperature mapping from FDM to FEM nodes
� If possible:
• avoid “black box” analysis functions to simplify model check
• use existing tools to provide reliable results and minimize userreluctance
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II. Current Status
FDM Thermal Analysis: Esarad, Thermica, Esatan …- Slower GMM creation without CAD/FEM interface+ Dedicated ray tracing and orbit analysis functions- Limited support for C & GL-calculation
+ But transparent and simple check of C & GL-calculation+ Flexible user coding in TMM- Temperatures must be transferred for FEM distortion analysis
FEM Thermal Analysis : Patran/Thermal …+ Very efficient GMM creation with aid of CAD input- Limited to TRIs, QUADs and Wedges- Lack of ray-tracing and orbital analysis capabilities+ Tools for automated C & GL-calculation available
- C & GL-calculation difficult to check+ Temperature mapping functions implemented
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IV. Thermal Distortion Work Flow
FDM Tools FEM Tools
CAD Input
GMM Creation
Radiative Analysis
Conduction & Cap.
Thermal Analysis
Post-Processing
Temp.Mapping
FEM Analysis
+ CAD interface
- Text based modeller
+ Several primitives
+ 3D GUI-Modeller
- TRI, QUAD & wedge only
+ Specular and diffuse - Diffuse reflection only
+ Partially automatic- Difficult to check
+ Flexible user coding - Limited user coding
- Mainly coded by user+ Future: Esatap
+ Plotting implemented+ Mapping on geometry
- Only for post-pro + Mapping onto FE mesh
+ Standard Application
- No CAD interface
- Manual (future: automatic)+ Easy to check
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CAD Input
GMM Creation
Radiative Analysis
Conduction & Cap.
Thermal Analysis
Post-Processing
Temp.Mapping
FEM Analysis
+ CAD interface
- Text based modeller
+ Several primitives
+ 3D GUI-Modeller
- TRI, QUAD & wedge only
+ Specular and diffuse - Diffuse reflection only
+ Partially automatic- Difficult to check
+ Flexible user coding - Limited user coding
- Mainly coded by user+ Future: Esatap
+ Plotting implemented+ Mapping on geometry
- Only for post-pro + Mapping onto FE mesh
+ Standard Application
- No CAD interface
- Manual (future: automatic)+ Easy to check
IV. First Interface Approach
FDM Tools FEM Tools
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Patran/TModel Creation
PatQController
View FactorForm Factor Calculation
QTranThermal Solver
Esarad/Thermica
I/F Program I/F Program
model.erg(Esarad Input)
model.d(Esarad Output)
vfin.dat (Geometry)template.dat (Opticals)
vfres.txt (Resistors)qmacro.dat (Transient Loads)micro.dat (Transient Loads)
qbase.dat (Steady State Loads)
IV. First Interface Approach
Data Transfer Scheme
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Heat fluxes calculated in Esarad:
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7,4
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6,4
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5,4
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7,3
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6,3
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5,3
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7,2
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6,2
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7,1
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,
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TT
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Q PATRANTOT σ�
�⋅
=qp qp
qpji GR
nnR
, ,,
( ) ( )[ ]44,
44,,,, IIIIIIIIIIIIIIIIIIIIIIIIIIIESARADTOT TTGRTTGRQQQ −⋅+−⋅⋅=+= σ���
Heat fluxes calculated in Patran:
� Three triangles of same size with same normal vector
� Surface Indices: p, q = I, II, IV Edge Indices: i, j = 1, 2, … 6
� Number of edges:
� REF of similar triangles:
3,3,3 === IIIIII nnn
0, ,,, == IIIIIIIIIIII GRGRGR
→ Heat flux values are identical for:
IV. First Interface Approach
Theoretical Verification of Radiative Approach
Two TRIs in FEM / FDM
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Geometry Transfer Test
IV. First Interface Approach
� Point, TRIs, QUADs and thermo-optical properties transferred correctly
� Interface software supports single and double sided surfaces
Geometry built in Patran/Thermal Geometry after transfer to Esarad
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Temperatures calculated with Esarad/Esatan
Radiative and Orbital Test
IV. First Interface Approach
� Test model to check radiative couplings
� Small temperature deviation between Patran/T and Esarad (next slide)
→ Algorithm for distribution and transfer of radiative couplings is correct
→ Transient orbit loads transferred correctly
°K °C
Temperatures calculated with Patran/Thermal
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Comparison of Temperature Results
IV. First Interface Approach
-0.015-28.150-28.16517
0.003-56.110-56.10716
-0.014-28.180-28.19415
-0.001-56.510-56.51114
-0.012103.770103.75913
-1.119-19.780-20.89912
2.269-24.340-22.07111
-1.117-19.880-20.99710
-1.143-19.960-21.1039
2.404-24.690-22.2878
-1.191-19.860-21.0517
-0.005145.410145.4056
0.310136.670136.9805
-0.328137.950137.6224
-0.007145.400145.3933
-0.337137.990137.6532
0.314136.690137.0041
Deviation [°C]:
Esatan Temp. [°C]:
Equivalent Patran Temp.* [°C]:
Esatan Node No.:
*Equivalent Patran temperatures are calculated as average edge temperatures of surfaces.
6 Esarad double-active nodes, corresponding to 12 single active Patran nodes.
Deviation excluding these nodes: 0.11 °C
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Linear Conductance and Capacitance in Patran
IV. First Interface Approach
� User friendly definition of properties for each element with GUI:
• Thermo-optical properties
• Thermal conductivity
• Specific heat
• Thickness …
� Automated capacity and conductor calculation supported by GUI
� Possibility to add linear conductors (e.g. for contact conduction)
� For rectangular elements: conductors between FEM nodes are in the form λ⋅A/d
� Conductor calculation for other element shapes is difficult to check
� No documentation for linear conductor calculation available
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CAD Input
GMM Creation
Radiative Analysis
Conduction & Cap.
Thermal Analysis
Post-Processing
Temp.Mapping
FEM Analysis
+ CAD interface
- Text based modeller
+ Several primitives
+ 3D GUI-Modeller
- TRI, QUAD & wedge only
+ Specular and diffuse - Diffuse reflection only
+ Partially automatic- Difficult to check
+ Flexible user coding - Limited user coding
- Mainly coded by user+ Future: Esatap
+ Plotting implemented+ Mapping on geometry
- Only for post-pro + Mapping onto FE mesh
+ Standard Application
- No CAD interface
- Manual (future: automatic)+ Easy to check
V. Second Interface Approach
FDM Tools FEM Tools
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V. Second Interface Approach
1. Step: GMM Creation in Patran/Thermal
Geometry in Patran/Thermal
� Finite element definition (TRIs, QUADs and wedges)
→ Efficient due to semi-automated meshing and CAD data import
� Assignment of thermo-opticals and element activity
� Grouping of elements:
→ Improves overview/transparency
→ Enables simple assignment of group thicknesses and properties
� Output: geometry and thermo-opticals
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� Geometry and thermo-optical check for each group
� Definition of properties for each group:
� Thermal conductivity
� Specific heat
� Thickness
� Output: Esatan Include file providing group properties
I/F file defining group properties
Geometry displayed in interface S/W
V. Second Interface Approach
2. Step: Group Property Definition with I/F
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V. Second Interface Approach
3. Step: GMM Conversion with I/F
Esarad Geometry provided by Interface S/W
� Automatic conversion of point
coordinates, surfaces and
thermo-optical properties
� Automatic group colouring
� Creation of Thermica Sysbas
file using TASverter (batch)
� Geometry file can by directly
used by Esarad or Thermica
� Output: Esarad (*.erg) and
Thermica (*.sysbas) files
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V. Second Interface Approach
4. Step: Capacitance Calculation with I/F
� Valid for TRIs and QUADs
� Semi-automated process
� Automated capacitance calculation for each element
� Formula is displayed and can be modified by user
� Use of group properties
� Specific heat
� Thickness
� Output: Esatan Include file defining element thermal capacities
GUI of Interface S/W for capacitance calculation
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V. Second Interface Approach
5. Step: Linear Conductor Calculation with I/F
� Valid for TRIs an QUADs
� Use of group properties
� Semi-automated process
� Automated linear conductor calculation for neighbouring elements
� Formula is displayed and can be modified by user (e.g. contact for insertion of conductance)
� Output: Esatan Include file defining linear conductorsGUI of Interface S/W for linear conductor calculation
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V. Second Interface Approach
6. Step: TMM Creation and Thermal Analysis
� Esatan skeleton file created automatically (e.g. by Esarad)
� Insertion of Include files created beforehand:
� Linear conductors
� Capacities
� Additional user coding (e.g. for heat sources, heat pipes)
� Esatan output:
Node (or element) temperatures
� I/F output:
Patran BDF file and Patran temperature input file
Esatan TMM with Include files generated before
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V. Second Interface Approach
7. Step: Temperature Mapping
Transferred geometry and temperatures Temperature map on FEM mesh
� Model geometry transferred with I/F to Patran (BDF file)
� Element data transferred with I/F to Patran (temperature input file)
� Interpolation of FEM element temperatures in Patran
� Finally: structural FEM distortion analysis
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� I/F software created to link Patran with Esarad/Thermica
� Favourite application: thermal distortion problems
I/F Approach 1:
� GMM and TMM defined in Patran/T
+ CAD and FEM structural model interface available
+ Automated linear conductor calculation
- No documentation for linear conductor calculation available
- Limitations on TRIs and QUADs
� Radiative couplings calculated in Esarad/Thermica
- Esatan input data transferred to Patran/T (TMM user coding restricted)
+ Patran/T results verified (theoretically and by simple test cases)
VI. Summary
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I/F Approach 2:
� GMM defined in Patran/T
+ CAD and FEM model interface
- Limitations on TRIs and QUADs
+ Semi-automated linear conductor and capacitance calculations
� Radiative couplings calculated in Esarad/Thermica
+ Esarad/Thermica surfaces can be added (e.g. cylinders, discs …)
+ Esatan TMM using Include files for conductance and capacitance
� Results transferred to Patran via BDF and temperature data files
� Mapping onto FEM mesh and thermal distortion analysis in Patran
+ Process already used in recent projects (early design phases)
VI. Summary (cont’d)