Human Body Co-Sim LifeModeler HillRom_Carlson

Human Body Co-Simulation LifeModeler/Marc

Mark Carlson, MSC.Software Corporation

Sundar Ananthasivan, HillRomAndrew Elliot, MSC.Software

MSC.Software Confidential

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Agenda

• Project Overview

• LifeModeler

• Co-Simulation

• Sample Results

• Potential Applications


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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


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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Co-Simulation – Technical Overview

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• 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


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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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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Animations: Bed Rest & Full Body on Foam

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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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Contact Details :

• For further information please contact

Mark CarlsonMSC.Software Corporation

4332 Brookside Ave.Minneapolis, MN 55436-1506

(952) 285-9968 [email protected]

Human Body Co-Sim LifeModeler HillRom_Carlson

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