human knee analysis ppt

Design and Analysis of Human knee and cartilage

Name of student Guided byNeeraj Jat Prof. K. NemaShaunak ChandwadkarKetul ShahAmey VaidyaSridutt Gokul

1

Outline• Objective• Introduction• Theoretical Background• Modeling details• Results and Discussion • Conclusion & Future scope

Objective

• To study stress and deformation phenomena of a human knee cartilage subjected to displacement and velocity applied in a form of impact• Determining cartilage properties and modelling its response• Comparison of Reaction Force obtained from different simulation

software and experimental data to justify our model• Provide pathway for further experiments for making Artificial

cartilage.

Introduction

• Cartilage is a fine viscoelastic rubbery tissue which acts as a cushion between the bones and the joints. People with cartilage damage commonly experience joint pain , stiffness and swelling• Causes of cartilage damage:• Direct blow: If a joint receives a heavy impact• Wear and tear: A joint that experience a long period of stress • Lack of movement : Long hours sitting due to nature of job etc.

• Current treatments available:• Knee replacement• Knee prosthesis

Statistical Survey and Motivation

• Bone: The femur, or thigh bone, is the longest, heaviest, and strongest bone in the entire human body

• The cartilage has the thickest layer between these two bones• Most of the injuries occur to the Knee

and hence it is chosen for modelling andanalysis

Theoretical Background

Modelling DetailsModelling

• Mimics (Materialise’s Interactive Medical Image Control System)• Easily and quickly create accurate 3D models from imaging data• Accurately measures in 2D and 3D• Exports 3D models to 3matic to optimize the mesh for FEA

Modelling DetailsSlicing femur bone from the big geometryExtrusion of cartilage over bone surfaceCreating virtual cells using virtual topology for simplifying geometry

Modelling Details2D 3D

Mesh size for cartilage: 0.1 mm Mesh size for Bone: 1mm (finer meshing)Mesh size for sphere: 0.3 mm Mesh type: QuadTested for: Static conditionBetween cartilage and bone: BondedBetween cartilage and sphere: BondedFixed support: BoneSimply supported: CartilageAnalysis load: Via sphere displacement 0.05 mm total displacement.

Mesh size for cartilage: 1 mm Mesh size for Bone: 3mm (finer meshing)Mesh size for sphere: 0.5 mm Mesh Type: TetrahedronsTested for: Static condition and Explicit Between cartilage and bone: BondedBetween cartilage and sphere: BondedFixed support: BoneAnalysis load-static: Via sphere displacementAnalysis load-dynamic: velocity. 0.05 mm/s velocity

Theoretical BackgroundDetermination of Material properties of bone and cartilage

Material Properties of BoneYoung's Modulus 12600-19400 MpaPoission's Ratio 0.3-0.39Shear Modulus 4850-5700MpaOperating Temerature 25 CDensity 1800 kg / m^3Material Type Solid Tensile Strength 50- 135 MpaCompressive Strength (-50) to (-250 )Mpashear Strength 65 Mpa

Material Properties of Cartilage

Young's Modulus: 0.06-0.020 Mpa

Poission's ratio: 0.45-0.49

Shear Modulus: 0.020 MPa

Temperature: 25 C

Density 1100 kg/m^3

Permiability 10^-15 to 10^-16 m^4/N

Material Type ViscoElastic (Porous)

Material Properties Of SteelYoung's Modulus 180 to 200GPaPoission's ratio 0.23 to 0.29Shear modulus 75 to 85 GpaYield strength 250 MpaUltimate Tensile Strength 550 MpaDensity 7800 kg/m^3

Modelling 2D and 3D

Modelling knee- static

Modelling knee-explicit

Experimental Setup• The Biomomentum’s Mach one machine was used to carry

out the experiments.• Cartilage Sample: Bovine articular cartilage sample.• Indentation velocity: 0.0025 mm/s• Indentation Depth: 0.05 mm• Sphere radius: 2.5 mm• Sample dimensions: 1 cm x 1 cm x 1 cm, with cartilage

thickness of 1m

Eq Stress 2D and 3D Total Deformation

Results & Discussion

Total deformation and force reaction (Static)



Equivalent stress and total deformation (Explicit)

Force reaction for 2D and experimental

0 1 2 3 4 5 6 70

0.00005

0.0001

0.00015

0.0002

0.00025

0.0003

0.00035

0.0004

Force Reaction (Y) [N]

0 10 20 30 40 50 60 70 80

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Chart Title

Series1 Series3 Series5 Series7


Force reaction for 3D knee-static and experimental

0 10 20 30 40 50 60 70 80

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Chart Title



0 10 20 30 40 50 60 70 80

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Force reaction 3D Knee static

Force reaction for 3D knee-explicit and experimental

0 10 20 30 40 50 60 70 80

-0.05

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Chart Title



0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

-1.00E-01

0.00E+00

1.00E-01

2.00E-01

3.00E-01

4.00E-01

5.00E-01

Force Reaction - 3D Knee ansys -Expilicit

Force reactions LS dyna vs Experimental

•

0 200 400 600 800 1000 12000.00E+00

5.00E-07

1.00E-06

1.50E-06

2.00E-06

2.50E-06

3.00E-06

3.50E-06

4.00E-06

4.50E-06

5.00E-06

Force Reaction ls-dyna Explicit

Time

Reac

tion

Forc

eResults & Discussion

Conclusion• The force reaction graph of all analysis shows the behaviour matches

the experimental behaviour of the cartilage.• Although not exactly as the cartilage, however as Cartilage is a Visco-

Elastic Bio material. And impossible to replicate, The results obtained are pretty good as expected. • This study can be further utilized to take a step towards in attempt of

making an artificial cartilage, Solving all the problems mentioned in the introduction part of the project.

human knee analysis ppt

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