Knee Simulation using ABAQUS

KNEE SIMULATION USING ABAQUS
March 15th, 2018
1400 Broadfield Blvd. Suite 325, Houston TX 77084
Phone : +1 (832) 301-0881
www.viascorp.com
Nishant Kumar
Senior Simulation Engineer
nkumar@viascorp.com
Arindam Chakraborty
VP of Engineering
achakraborty@viascorp.com

© 2018 Virtual Integrated Analytics Solutions Inc. 2
Agenda
▪ Company Overview
▪ Simulation in Life Science
▪ Abaqus Knee Simulator (AKS)
▪ AKS Workflows
▪ Value Proposition
▪ Q&A

VIAS Overview
Engineering
Consultancy
Training
Automation &
Customization
Software
© 2018 Virtual Integrated Analytics Solutions Inc.
• Multiple Industry Experience – Energy and Process, Life
Science, Manufacturing, Hi-tech, Aerospace, etc.
• Presence in Houston, Chicago, Cincinnati, San Francisco,
Detroit
• Team consists of Ph.D.s and Masters in Solid Mechanics,
Fluid Mechanics, Materials and Corrosion, Numerical
Analysis, Statistics; Optimization and Reliability
• Solution partner of Dassault Systèmes products – SIMULIA
(Abaqus, Isight, fe-safe, Tosca), CATIA, DELMIA,
3DEXPERIENCE
• Provides Virtual Design Experience through Collaboration
and Data Analytics – Provides Automation and Customization
• Provide 3D Printing and AM Simulation Services
33

Our Technical Capabilities
Composite and
Elastomer Modelling
Additive
Manufacturing
Simulation
Simulation
Automation
Patient Specific
Simulation
4
Design Analysis
and Virtual Testing
using Simulation
Fatigue / Fracture /
Damage
Optimization and
Reliability
Multi-physics
Simulations (CFD,
EMAG, FSI)
4

Realistic Simulation for LS Industry - Trend
66

Realistic Simulation for LS Industry
77
Design Exploration
Material Choices
and Geometries
Manufacturing
Tolerances
Fatigue and Failure
Stress
Concentration
Cyclic loading
Patient Specific
Realistic Patient
Geometries
Realistic Loading
Conditions
Understand
Device
Effectiveness
Device Safety
Predict
Device Durability,
Reliability and
Potential Failure
Mitigate
Reduce Risk of
Device Failure in
Patients
Why?What?How?
Realistic Simulation and Durability Evaluation
Optimize Device Effectiveness and Safety
RoleofRealisticSimulation
Faster
Better
Cheaper

SIMULIA Software Capabilities
88

Application: Simulation of Joint Forces Due to
Exoskeleton Structure
• FE model of entire limb with simplified axial
connectors (simulates muscles / muscle
contractions) and detailed bone geometry.
• Knee joint as a modified hinge joint with 3 DOFs
• Stresses at joint to design external device design
to fit patient specific requirements
Upper
Brace
Lower
Brace
Flexible
Linking
Structure
99

Introduction
What is the knee simulator?
• Abaqus Knee Simulator (AKS) is an automated
modeling tool for building advanced knee implant
simulations based on a validated framework
• Abaqus Knee Simulator includes five workflows
which cover various aspects of knee implant
design evaluation:
➢ Contact mechanics
➢ Implant constraint
➢ TibioFemoral (TF) constraint
➢ Wear simulator
➢ Basic Total Knee Replacement (TKR) loading
1
1

Knee Parts Tab
Hex mesh for contact area
Meshed automatically
Knee Parts
13

Test Suites Tab
Models created automatically
Test Suites
14

Output Request
Result Visualization
Simulation Options
Vizualization
15

Model Validation
• Model validation key to success
• Current literature demonstrating explicit FE model validation
including predictions of
• Contact mechanics (material models, contact algorithms)
• Tibiofemoral, patellofemoral kinematics under known dynamic
loading
• Wear performance
16

Model Validation (Cont.)
• Wear simulator– prior model validation work
• From Knight et al., 2007, J Biomechanics
17

Contact Mechanics
Implant Constraint
Tibiofemoral
Constraint
Wear Simulator
Basic TKR Loading
Workflows
Is being refined in the
latter stages of the FDA’s
Medical Device Diagnostic
Tool (MDDT) program.
19

Contact mechanics workflow
Objective: predict contact mechanics
and stresses of the components under
basic loading conditions, and facilitate
comparison of devices
A constant or varying compressive
load is applied to the femoral
component, with a prescribed medial-
lateral load distribution, to bring the
implants into contact
Contact Mechanics
20

Contact mechanics workflow
The femoral component is flexed to a
prescribed flexion angle, with choices of
fixed or free degrees-of-freedom for
medial-lateral (M-L) translation, internal-
external (I-E) rotation and varus-valgus
(V-V) rotation
Contact area, peak and average contact
pressure, and stress in the components
are reported throughout the simulation
Contact Mechanics (Cont.)
21

Implant constraints workflow
Objective: Evaluate the laxity for a set of
femoral and tibial components without
surrounding soft tissue structures
Anterior-posterior (A-P) displacement,
internal-external (I-E) rotation and medial-
lateral (M-L) displacement tests available
Constraint Workflow - Implant
22

Implant constraints workflow
The tests may be preformed at a series of flexion
angles
a displacement or rotation is applied in both directions
under a prescribed compressive load
with fixed or free options for the remaining degrees-of-
freedom
the force or torque generated on the insert is measured
Kinematic, force, contact mechanics and stress data is
produced from each test
Constraint Workflow - Implant (Cont.)
23

Tibiofemoral (TF) constraints workflow
Objective: describe the laxity of the
tibiofemoral joint, with physiological
ligamentous constraint, for a specific implant
design
The workflow includes femur and tibia bones,
femoral and tibial components, plus 1-D or 2-
D representation of the primary ligaments
crossing the tibiofemoral joint
Constraint Workflow - TF
24

Ligaments can be selectively included or omitted
from the analysis
A compressive load is applied and a series of
laxity tests (A-P, I-E and V-V), performed at
prescribed flexion angles, are available
For each test, a load (an A-P force, I-E torque or
V-V torque) is applied to the joint, with remaining
degrees-of-freedom selected as either fixed or
free
Constraint Workflow - TF (Cont.)
25

Ligament mechanical properties (initial tension,
linear stiffness) can be adjusted to evaluate the
influence of variability in ligament properties, or
to recreate specimen-specific data
Location of femur, tibia and their associated
ligament attachment sites can be shifted
Six-degree-of-freedom kinematics, ligament
forces, insert forces, stresses and contact
mechanics are available as outputs
Constraint Workflow - TF (Cont.)
26

Wear simulator workflow
Objective: predict wear (wear
volume, maximum linear wear depth,
and average linear wear) over a
prescribed number of cycles
Femoral and tibial components only
(no bone or soft-tissue) are included
in the analysis
Wear Workflow
27

Wear simulator workflow
Mechanical restraint is provided in the anterior
and posterior directions to simulate behavior of
the cruciate ligaments
A typical gait cycle, taken from ISO standards,
including flexion profile, compressive load, A-P
force and I-E torque is simulated
Linear Archard’s Law or Cross-shear wear
algorithms may be selected to predict wear on the
insert
Wear Workflow (Cont.)
28

Basic total knee replacement (TKR)
loading workflow
Objective: evaluate tibiofemoral and
patellofemoral kinematics, contact
mechanics, component stress, ligament and
muscle forces under physiological loading
conditions for a variety of activities of daily
living
In addition to femoral and tibial bones and
components, and 1-D and 2-D soft-tissue
representation, the extensor mechanism
(patella bone, patellar implant, patellar
tendon and quadriceps) is also represented
in the model
TKR Workflow
29

Basic total knee replacement (TKR) loading
workflow
The quadriceps could be either represented as
a single bundle, or as multiple bundles,
including medial and lateral longus and oblique
structures
A variety of activities (gait, squat, chair-rise,
stepdown) may be simulated, with loading
profiles dependent on the choice of activity
TKR Workflow (Cont.)
30

Basic total knee replacement (TKR)
loading workflow
A (activity-dependent) flexion profile is applied
to the femur, while quadriceps force is
distributed among the quadriceps bundles
Kinematics in Grood-Suntay co-ordinate, contact
areas and contact pressure outputs are obtained
TKR Workflow (Cont.)
31

Abaqus Knee Simulator (AKS)
3535

Key Members
ARINDAM CHAKRABORTY, Ph.D., P.E.:
Dr. Chakraborty has a Ph.D. in Mechanical Engineering from the University of Iowa, and has over 10 years of experience in solid
mechanics and design, non-linear FEA, fatigue and fracture mechanics, reliability analysis, composite structures in Oil & Gas,
Nuclear and Structural Design. His Areas of expertise lies in Solid Mechanics & Design, ASME Code (Sections II, III, VIII) Based
Strength and Fatigue Analysis, System Reliability, Component Reliability and Optimization, Probabilistic Analysis. He has
extensive experience in Fatigue and Fracture Mechanics, FEA, Probabilistic Analysis. Dr. Chakraborty has chaired numerous
conference sessions, and is involved with ASME code committees and has extensive journal & conference publications.
PRABHAV SARASWAT, Ph.D.:
Dr. Saraswat has a Ph.D. in Bioengineering from the University of Utah and is an engineer with more than 10 years experience in
solving challenging problems of computational and experimental bio-mechanics. His expertise includes human motion capture,
gait analysis, musculo-skeletal modeling, finite element simulation, process automation, and optimization. He was a Technical
Specialist - Virtual Human Modelling at Dassault Systemes for around 6 years and is experienced using the SIMULIA portfolio
(Abaqus, Isight, Tosca, fe-safe) for a variety of life sciences applications. He also has extensive journal & conference publications
to his name.
NISHANT KUMAR, M.Sc.:
Mr. Kumar is a senior simulation engineer with masters in Ocean Engineering and Naval Architecture. He has almost 10 years of
international working experience in construction and engineering consultancy business. His experiences span over ship building,
Hydrostatic and Hydrodynamic calculations, project engineering, FEA consultancy, fatigue-life calculations, parametric and non-
parametric optimizations, training, sales and marketing. He has vast experiences in coding using Python, Matlab, Fortran. He has
worked with different industries including, but not limited to bioengineering/biomedical devices, defense and electronics
packaging, and high performance computing. Nishant is a certified Simulia trainer and technical support personal. He has
extensive experience in public speaking and cross culture communications.
SRIKANTH SRIGIRIRAJU, PH.D.:
Dr. Srigiriraju is a mechanical Engineer with over 10 years of experience in customer-support and consultancy in using Abaqus for
both big and small companies from diverse industries: biomedical, automotive, aerospace, heavy-machinery,, consumer goods &
packaging etc. He has expertise in various structural and thermal procedures of Abaqus and its features with specific focus on:
connectors, Abaqus-Dymola co-simulation, co-simulation between different Abaqus products, Discrete Element Methods, contact
& constraints. He is fairly experienced in using Dymola, CATIA, Solidworks and 3DEXPERIENCE. He graduated from Brown
University with a Doctorate in Solid Mechanics and Masters in Applied Mathematics.

Team Members
45
Sr
No.
Name Email Role
1 Arindam Chakraborty achakraborty@viascorp.com VP – Advanced
Engineering
2 Prabhav Saraswat psaraswat@viascorp.com AKS Consultant
3 Srikanth Srigiriraju ssrigiriraju@viascorp.com Director - Software
Technical Services
4 Nishant Kumar nkumar@viascorp.com Senior Simulation
Engineer

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Knee Simulation using ABAQUS

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