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Human Body Co-Simulation LifeModeler/Marc
Mark Carlson, MSC.Software Corporation
Sundar Ananthasivan, HillRomAndrew Elliot, MSC.Software
MSC.Software Confidential
27/04/2009 2
Agenda
• Project Overview
• LifeModeler
• Co-Simulation
• Sample Results
• Potential Applications
MSC.Software Confidential
27/04/2009 3
Project Goals
• Develop a simulation tool which enables study of the Human Body's interaction with highly non-linear flexible environments
• External interfaces with non-linear materials – Comfort – Medical Equipment/Devices
• Internal loads development – Skeletal motion effects on organs
• Soft tissue inclusion – Pressure Sores – Muscles – Ligaments (with Failure)
• Contact Precision – Joint Wear/Deterioration
MSC.Software Confidential
LifeModeler
• Specialized Adams Plug-in Component• Anthropometric Database
– Gender, Height, Weight, Age – Human Percentile – Nationality: USA, UK, Japan, China
• Automatic Human Body Generation– Joints, Muscles, Ligaments
• Passive Model– Model reacts to external loads from the environment
• Active Model– Model internally generates loads/motion to effect the environment – Motion Agent --> Reverse Kinematics (teach muscles) --> Forward Kinematics (activate
muscles)
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MSC.Software Confidential
Co-Simulation – Technical Overview
4/27/2009 5
• Glue Code – Courtesy of (& thanks to) Andy Elliott – Governs all data exchange – Facilitates Time Stepping – Interpolates/Extrapolates as necessary
• Adams/LifeModeler– Generates solution to the next Marc time step – Rigid body velocities passed to Glue (translational & rotational for each human body
segment) – Glue interpolates for overshoot – Passes to Marc
• Marc – Solution for external loads (from FEM contact) on body segments at current time step – Forces/Moments passed to Glue – Glue extrapolates a predicted force for next Marc step – Passes to Adams/LifeModeler
MSC.Software Confidential
Co-Simulation – Adams & Marc
• Capabilities/Limitations – No Known Limitations from either the Marc or Adams side when performing a co-sim– Advanced non-linear material model availability – Adaptive Meshing Inclusion – Time Stepping Control
• Each code allowed to time step natively • Cut-Backs Automatically Administered • Data passing upon convergence only
• Settling Control – Reducing dynamics increases solution efficiency – Adams = Fully Dynamic; Marc = Quasi-Static (dynamic available if desired) – Minimize release height with a MOVE step
• Adams only solution • Eatablishes the equilibrium position of the body on a rigid surface representing the top of the
bed (the undeformed FE mesh state) • The Marc MOVE option repositions body segments prior to initializing the co-sim
– Body Segment Damping • Individual segments have grounded dampers (on the Adams side) • Tuned to be as close to critical damping as possible to reduce rebounding
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MSC.Software Confidential
Sample Results – Surface Maps
• Physical Test – Pressure Sensing Pad by X-Sensor – Allows for direct comparison with analysis results
• Contact Normal Stress
• Soft Tissue Inclusion – Rigid Body Segment
Bi-Sected– Mesh created on "calf"
bi-section – Glued contact at "shin"
interface
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MSC.Software Confidential
Animations: Bed Rest & Full Body on Foam
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MSC.Software Confidential
Possible Use Cases
• Loads development for implanted devices
– Pacemakers
• Comfort – Automotive Seating, Hospital Beds,
etc.
• Physical Therapy/Rehabilitation
• Athletics– Training, Injury, Bracing
• Co-Sim with LifeModeler– FEA Muscles Driving Skeletal Bio-
Mechanics
• Surgical Implications – Healing/Recovery – Scarring
• Neurological Feedback – Balance/Stability
• Cardiologic Studies – Pacemaker Leads – Valve Replacement
• Enhanced Artery Modeling w/FE Muscles
– Stent Analysis
• Non-Biomedical Co-Simulations
– Any condition where non-linear flexible components (Marc) interact with complex rigid body dynamics (Adams)
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MSC.Software Confidential
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Contact Details :
• For further information please contact
Mark CarlsonMSC.Software Corporation
4332 Brookside Ave.Minneapolis, MN 55436-1506
(952) 285-9968 [email protected]