Bildgebende Verfahren als. Control 2011 Alexander Nolte CADFEM GmbH

Transcription

1 Bildgebende Verfahren als Basis für die FEM-Simulation Control 2011 Alexander Nolte CADFEM GmbH

2 CADFEM: FEM Software and Services CADFEM FEM Software & Services 25+ years experience 140+ employees 40 Mio. revenue Central Europe: 12 offices Privately owned Worldwide through partners & TechNet Alliance CADFEM Innovative Certification: ISO 9000 ANSYS Competence Center FEM ANSYS Channel Partner since different seminar topics 100+ ANSYS technical & sales engineers CADFEM Complementary Software Explicit analysis AUTODYN and LS-DYNA Metal forming FTI, eta Robust analysis optislang Materials ESAComp, DIGIMAT Acoustics Biomechanics AnyBody Software Seminars Support Consulting Customization ti

3 CADFEM Innovative Medical Applications Materials Patient-individual simulations FEM Micro Meso Nano Quantum Musculoskeletal l l simulations i

4 Anwendungsgebiete der FEM Medizin Elektronik Konsumgüter Maschinenbau Automobil Luft- und Raumfahrt, Bauwesen

5 Biomechanical FEM Simulation Procedure analog to classical FEM Simulation Simulation model generation FEM Simulation Preprocessing: FEM model setup Solution: Solving mathematical equations Postprocessing: Evaluation of the results But: we have to deal with several problems for biomechanical FEM simulations

6 Biomechanical FEM Simulation Preprocessing: FEM model setup Geometry generation / Meshing Typical FEM packages are developed for CAD meshing but not for STL meshing STL geometry mesher is needed Material modeling Typical FEM packages are developed for engineering g materials like steel or rubber. For special biological tissues proper material models might not be available in the standard. Biological materials are typically highly complex Boundary conditions Difficult to determine the complex load pattern which are acting e.g. on a bone during gait several muscles act on the bone; joint reaction forces Contact modeling Determination of proper contact definitions between the implant and the bone

7 Geometry generation Biomechanical FEM Simulation Anatomical structures have to be reconstructed from images (DICOM format) Additional parts e.g. implants have to be placed into the geometry of the anatomical structures Reconstructed geometry is typically exported to a geometry description in the STL format STL format: point cloud where points are connected by triangles. The surface is facetted no smooth surface description like in real CAD format Cylinder in STL Format: - facetted surface - ca. 205 KB Cylinder in CAD format: - smooth surface -ca. 11 KB STL triangle Points of point cloud

8 FEM application in trauma surgery How many screws? Monocortical or bicortical?

9 Patient-individual Virtual Breast Operation Partner FEM simulation of breast deformation after insertion of the implant

10 Patient-individual shaft Partner Patient Segmentation of CT Data and geometry Bone Model Muscle Model Fat Model Full Model with Shaft Meshing and FEM simulation in ANSYS

11 Patient-individual shaft

12 Patient-Individual Virtual Dental Implant Insertion Implant Planning Tool Automated model generation and simulation

13 Patient-Individual Virtual Abdominal Aneurysm Investigation Aneurysm Dangerous extension of blood vessels Material Law DICOM Segmentation in Mimics Development of an anisotropic, hyperelastic material model in ANSYS for aortic walls (according to Prof. Holzapfel, TU Graz) Structural simulation or Fluid flow simulation

14 AnyBody Input Human model from repository: Muscles Bones Joints Motion Rigid bodies, inverse dynamics & optimization Output Muscle force, activity, work, joint reaction forces, motion data... External loads

15 AnyBody Deformation from musculoskeletal 0.02 s, 18x scale

16 came Zeitschrift: Computer Aided Medical Engineering Brückenschlag von Forschung zu Praxis Fachbeiträge Grundlagenbeiträge zu Segmentierung, FEM und Anatomie

17 CADFEM Medical: The complete workflow from imaging to the FEM model