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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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)