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

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 Dieter Pahr 2

Ov Overwi wiew Introduction to medtool Setting up an FEA project Hands-on Questions Summary Dieter Pahr 3

medtool ool 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

Idea b behind medtool ool: S Scr cript Manager  A simple script: python circleArea.py −rad 15.0 [−out file.txt ]  Python Code: Dieter Pahr 5

Idea b behind medtool ool: 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, …) 1 3 2 4 Dieter Pahr 6

Getting Started w with medtool ool  Download the trail version: medtool help www.dr-pahr.at User: home Pass: drpahR1=  Have a look to the “Help”  Work through “Examples” Dieter Pahr 7

Ov Overwi wiew Introduction to medtool Setting up an FEA project Hands-on Questions Summary Dieter Pahr 8

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

FE FEA Model T Typ ypes Dieter Pahr 10

Ov Overwi wiew Introduction to medtool Setting up an FEA project Hands-on Questions Summary Dieter Pahr 11

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

Step 2: C Calibration  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 Dieter Pahr 13

Step 3: E Edit itin ing - Modifications  crop ROI (region of interest)  re-coarse image  rotate/register image  … Dieter Pahr 14

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

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

Step 6 6: Material al M Mapping Interpolated mapping  map gray-values to elasticity  direct  voxel models  interpolated  smooth models  mapping law: Dieter Pahr 17

Step 7 7: FE FEA M Modeling – Pre re-proc ocessing g  creating solver input decks  Abaqus/Calculix format  medtool philosophy: “includes”  automatically - mesh  automatically - material  via node sets - loading - main file  by hand or external pre-postprocessors Dieter Pahr 18

Step 7 7: FE FEA M Modeling - Results Analyzing FEA results:  read solver output files via scripts  use medtools XY-plot , Excel, … Viewing FEA results  external post-processors  Abaqus, HyperWorks, Paraview, … Dieter Pahr 19

Ov Overwi wiew Introduction to medtool Setting up an FEA project Hands-on Questions Summary Dieter Pahr 20

Questi tions Do you have any questions, remarks, … Dieter Pahr 21

Ov Overwi wiew Introduction to medtool Setting up an FEA project Hands-on Questions Summary Dieter Pahr 22

Summa mmary CT based FEA:  Challenge: “Individualization”   automatization, parametrization, …  Choose the right tool for your task! Dieter Pahr 23

Thanks f for y your Attention! Contact Dr. Pahr Ingenieurs e.U. Einöde 11 2511 Pfaffstätten, Austria +43 664 588 02 93 office@dr-pahr.at Dieter Pahr 24