2008 international ansys conference · 2008 international ansys conference ... © 2008 ansys, inc....

© 2008 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary

2008 International ANSYS Conference

Bringing Finite Element and Musculoskeletal Modeling together using Any2Ans Interface

Can Ozcan, MSMEDirector of EngineeringOZEN ENGINEERING

© 2008 ANSYS, Inc. All rights reserved.2 ANSYS, Inc. Proprietary

What is AnyBody and ANSYS?

• AnyBody is a multibody dynamics system which includes muscle modelling capabilities

• AnyBody is developed by Aalborg University and AnyBody Tech., Denmark

• ANSYS is the industry leader computational simulation software company, providing Multiphysics codes

• ANSYS has offices worldwide and HQ in Pittsburgh


What is Any2Ans?

• Interface between AnyBody and ANSYS• Easy and convenient way of performing rigid-

flexible analysis using two best of the market software

• A nice integration to the Biomedical design process


Test Case – Spine Implant

• As a test case; a simple spine implant is studied



• AnyBody project standing lift (lateral bending) from Aalborg repository is used



• Movement of spine vertebrae are restrained by implant

• AnyBody uses a spinal rhythm model for determining individual vertebra movements by approximating the segments as a bending beam with variable stiffness

• To effect the immobilization from the implant, the stiffness coefficient between the two vertebra is set to zero



• Any2Ans is used to extract the movement, force and geometry data from AnyBody study



• Bone geometry is brought into ANSYS DesignModeler in IGES format

• Parametric redesign of implant in ANSYS DesignModeler • Design positions can be multiplied with different export

operations using Any2Ans• Rigid-Flexible dynamics

capability in Ansys Workbench is used

• Movements are established using body-to-ground connections

• Force is applied at L1-L2 joint location

• Displacements are specified at L3 segment



• Stress, Safety Factor, Fatigue results are extracted

• Joint forces between L2-L3 vertebra is extracted

• Effect and performance of implant can be studied with realistic movement and force data



• Joint force between L2 & L3 vertebra is decreased ~40%


Test Case – Arm Curl

• Upper Arm (Humerus) and Fore Arm (Ulna) modeled holding a dumbell

• Build in Anybody for proof of concept with two bones and four muscles

• Joint movements are specified for motion



• Rigid Body representation built in Ansys Environment, and confirmed to match AnyBody results



• Fore Arm is replaced with flexible body and corresponding forces & joint connections are carried on to new finite element mesh



• Stress, strain, fatigue analysis and more detailed type of analysis becomes available with the integration


• AnyBody project is created / modified– Project file saved under *.main.any

• Any2Ans can read main project files and search through referenced AnyBody files (*.any) for bone data

• Main project file is modified automatically to extract bone movement data

• AnyBody is called in batch mode in the background to generate the movement / force data

How does Any2Ans work?

*.main.any

*.main.any

Modified *.main.any


• Bone geometry in AnyBody is in *.anysurf and/or *.stl format and sent to ANY2ANS

• Movement and force data is written to .csv files by AnyBody and sent to ANY2ANS

• ANY2ANS writes out XML files and/or APDL input files of movement and force for Ansys Workbench environment

• ANY2ANS also writes out geometry files

How does Any2Ans work?

STL/AnySurf Files.csv Files

Repository IGES

STL

.XML Files / ANSYS Input Files

IGESANSYS

WORKBENCH


Any2Ans Capabilities

• Dynamically read and understand AnyBody projects by parsing using ANTLR

• Extract bone geometry & movements, muscular forces and joint reactions from AnyBody

• Quasi-static or dynamic movement for full motion• Selective export of bones based on analysis needs


Any2Ans Capabilities

• Export ANSYS APDL input files which rebuilds the Anybody model

• Export ANSYS format XML files of movement for the related STL file

• Converts AnyBody geometry format to STL• Display bones & movements for inspection at all time steps

before export


Next Steps

• Improve user interface to enhance quality & detail of the analysis performed– User inputs are welcome

• Add coupling capabilities as needed– Backward coupling to Anybody Software– Two-way coupling with Anybody Software


Contacts

• Ozen Engineering, Inc.Address: Internet:1210 E. Arques Ave.www.ozeninc.comSuite 207/208Sunnyvale, CA 94085

Phone Lines: Fax:408-732-4665 408-834-4557

Email:Information - [email protected] (Account Managers) – [email protected] – [email protected]

2008 international ansys conference · 2008 international ansys conference ... © 2008 ansys, inc....

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