Cr Creating F FE M Models f from C CT D Data Dr. Dieter Pahr, - - PowerPoint PPT Presentation

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Cr Creating F FE M Models f from C CT D Data Dr. Dieter Pahr, - - PowerPoint PPT Presentation

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Cr Creating F FE M Models f from C CT D Data Dr. Dieter Pahr, CEO Dr. Pahr Ingenieurs e.U. www.dr-pahr.at IBDW/ESUCB Banz, June 26, 2017 Ov Overwi wiew Introduction to medtool Setting up an FEA project Hands-on Questions Summary

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Cr Creating F FE M Models f from C CT D Data

  • Dr. Dieter Pahr, CEO
  • Dr. Pahr Ingenieurs e.U.

www.dr-pahr.at

IBDW/ESUCB Banz, June 26, 2017

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SLIDE 2

Ov Overwi wiew

Introduction to medtool Setting up an FEA project Hands-on Questions Summary

Dieter Pahr 2

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SLIDE 3

Ov Overwi wiew

Introduction to medtool Setting up an FEA project Hands-on Questions Summary

Dieter Pahr 3

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SLIDE 4

medtool

  • ol Fea

eatur ures es

“From 3D images to FEA models”

  • image processing & analysis
  • FEA meshing & modeling
  • workflow (provenance) system
  • (user) script manager
  • parameter study (multi-dataset)
  • report maker
  • …

Dieter Pahr 4

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SLIDE 5

Idea b behind medtool

  • ol: S

Scr cript Manager

  • A simple script:

python circleArea.py −rad 15.0 [−out file.txt]

  • Python Code:

Dieter Pahr 5

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SLIDE 6

Idea b behind medtool

  • ol: P

Provenan ance system

Need to know …

  • 1. name of script (list)
  • 2. (active) parameters of each script
  • 3. parameter variable ( $radius )
  • 4. parameter values (CSV/XLS list  $radius = 12.3, …)

Dieter Pahr 6

1 2 3 4

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SLIDE 7

Getting Started w with medtool

  • ol
  • Download the trail version:

www.dr-pahr.at

User: home Pass: drpahR1=

  • Have a look to the “Help”
  • Work through “Examples”

Dieter Pahr 7

medtool help

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SLIDE 8

Ov Overwi wiew

Introduction to medtool Setting up an FEA project Hands-on Questions Summary

Dieter Pahr 8

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SLIDE 9

Project ct D Definition Ph Phase

  • scanning

 alignment, type, storage, …

  • mechanical testing

 setup, measurements, …

  • modeling strategy

 tools, FEA type, …

  • verification & validation

 model checks, …

  • documentation

 data handling, reports, …

Dieter Pahr 9

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SLIDE 10

FE FEA Model T Typ ypes

Dieter Pahr 10

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SLIDE 11

Ov Overwi wiew

Introduction to medtool Setting up an FEA project Hands-on Questions Summary

Dieter Pahr 11

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SLIDE 12

Step 1: I Initial Setup & & Data C Check ck

  • Set work directory
  • Create directory structure
  • Copy data files
  • Make info script
  • Check files with “Image 

Processor”

Dieter Pahr 12

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SLIDE 13

Step 2: C Calibration

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  • CT gives HUs (Hounsfield units):
  • air ≈ -1000, water ≈ 0,
  • bone ≈ 500-1500
  • FE needs BMD (bone mineral density):
  • from HU via phantoms
  • or BV/TV (bone over total volume):
  • from BMD via calibration equation

Dall'ara et.al. Bone, 2013, 52, 27-38

  • Hint: 0-250 scaling
  • BV/TV = 0…1 gray value = 0…250
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SLIDE 14

Step 3: E Edit itin ing - Modifications

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  • crop ROI (region of interest)
  • re-coarse image
  • rotate/register image
  • …
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SLIDE 15

Step 4: S Segmentation

  • automatic segmentations
  • fixed thresholds
  • “fill” regions outside &

thickness

  • interactive segmentation
  • “labeling” by hand
  • e.g. with Fiji, Slicer, …
  • further modifications …
  • embedding

Dieter Pahr 15

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Ste tep 5 5: Meshing - hFE

  • Block meshing (multi-material)
  • 2D or 3D meshing
  • cortex meshing (bone mesher)
  • smooth or voxel mesh
  • micro and macro meshes
  • convert image formats

Dieter Pahr 16

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Step 6 6: Material al M Mapping

  • map gray-values to elasticity
  • direct  voxel models
  • interpolated  smooth models
  • mapping law:

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Interpolated mapping

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Step 7 7: FE FEA M Modeling – Pre re-proc

  • cessing

g

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  • creating solver input decks  Abaqus/Calculix format
  • medtool philosophy: “includes”
  • mesh

 automatically

  • material

 automatically

  • loading

 via node sets

  • main file  by hand or external pre-postprocessors
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Step 7 7: FE FEA M Modeling - Results

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Analyzing FEA results:

  • read solver output files via scripts
  • use medtools XY-plot , Excel, …

Viewing FEA results

  • external post-processors
  • Abaqus, HyperWorks, Paraview, …
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SLIDE 20

Ov Overwi wiew

Introduction to medtool Setting up an FEA project Hands-on Questions Summary

Dieter Pahr 20

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SLIDE 21

Questi tions

Do you have any questions, remarks, …

Dieter Pahr 21

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SLIDE 22

Ov Overwi wiew

Introduction to medtool Setting up an FEA project Hands-on Questions Summary

Dieter Pahr 22

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SLIDE 23

Summa mmary

CT based FEA:

  • Challenge: “Individualization”
  •  automatization, parametrization, …
  • Choose the right tool for your task!

Dieter Pahr 23

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SLIDE 24

Thanks f for y your Attention!

Contact

  • Dr. Pahr Ingenieurs e.U.

Einöde 11 2511 Pfaffstätten, Austria +43 664 588 02 93

  • ffice@dr-pahr.at

Dieter Pahr 24