1. Thesis Supervisor:
Dr. Mukul Shukla
Associate Professor
MED, MNNIT, Allahabad
Surya Pratap Singh
M.Tech- CAD/CAM
2015CC16
MED, MNNIT, Allahabad
Design & Finite Element Analysis
of Lattice Structure
based Orthopaedic Implants
State-Of-Art Presentation
Department of Mechanical Engineering
Motilal Nehru National Institute of Technology, Allahabad(India)

2. Content
• Introduction to Area of research
• Challenges in the field
• Literature Review
• Findings from research papers
• Objective
2

3. Introduction to
orthopaedic implants
3

4. Introduction
• In orthopaedic there is a big problem of
segmental bone defect .
• In segmental bone defect a long bone is
separated in two or more parts with a large
gap.
• The reason behind this defect can be a high
energy impact or diseases like bone cancer.
4

5. Types of Bone Defect
5
Ref:https://www.studyblue.com/notes/note/n/commonly-named-skeletal-fx/deck/6147305 @10/oct/16

6. X-ray Images of bone defects
6
Slow improvement of
bone regeneration
Ref: SCOTT P. BRUDER et.al The Effect of Implants Loaded with Autologous Stem Cells on the Healing of Canine Segmental Bone Defect
J Bone Joint Surg Am, 1998 Jul; 80 (7): 985 -96

7. 7
X-ray Images of bone defects

8. Solutions to the problem
• A general solution of this kind of problem is
use of bone plates to fix two separated bone.
• But sometimes when gap is large in bone then
bone plat is not a sufficient option.
• In those cases we need a scaffold.
• This scaffold can be of two types:
1. Natural 2. Artificial
8

9. Natural Scaffolds
• Natural Scaffold- also known as biological substitutes.
• In this category Autograft and Allograft are included.
Autograft
(ABG- Autologous bone grafting)
A graft of tissue from one point to another of the same
individual's body.
Allograft
A tissue graft from a donor of the same species as the
recipient. Allograft is a good alternative to ABG
9

10. Limitations of Natural Scaffold
Autograft Limitations
• The harvesting process from donor site has been associated with
perioperative and post operative complications and morbidity.
• A prolonged surgical and anaesthesiological time can cause a
proportionally increased risk of infection.
• The cost of harvesting can be equivalent to the cost of commercial
available bone graft
Allograft Limitations
• Major risk of using allograft are viral disease transmission and bacterial
infection.
• Recognized as “ Non-Self”, the allograft is attacked by the immune
system.
10

11. Artificial Scaffold
Scaffolds can be of two types
11
Polymer based
• Polymeric scaffolds are
biodegradable but have low
load bearing capacity.
• CaP, Pla ,Calcium Sulphate,
Bioactive glasses are some
commonly used polymeric
materials.
Metal based
• Metallic scaffold can bear more
load without deflection or
fracture.
• Metal are not bio-degradable
except Mg alloy.
• Limited metals can be used
• Ti6Al4V,Stainless steel,
Co-Cr alloy, Ni-Ti alloy

12. Solution for
Segmental Bone Defect
12
a. Segmental bone defect b. Bone defect filled with metallic lattice structure c. Full view of assembly of bone plate and lattice structure
Ref: Jan Wieding et.al Finite element analysis on the biomechanical stability of open porous titanium scaffolds for large segmental bone defects under
physiological load conditions “Medical Engineering & Physics 35 (2013) 422–432”

13. Challenges In the Field
13

14. Challenges in Scaffold Design
• Selection of Bio-Compatible Material
• Need of Metallic Scaffold
• Controlled Porosity
• Compressive Strength
• Patient specific implant designs
• Complexity of manufacturing
• Cost of manufacturing
14
Lattice
Structure
Additive
Manufacturing

15. Literature Review
15

16. Literature Review
Areas Covered in Literature review -
1. Conceptualization of bone scaffold form designing to plantation –(8,5)
2. Stress Analysis of Femur Bone
3. Properties of scaffold(5,6)
4. Design Of Lattice Structure-(4,7)
5. Manufacturability of Lattice Structure by using Additive Manufacturing
techniques -SLM,EBM-(2,3)
6. Materials For Scaffold-(10)
7. Compressive Strength analysis of scaffold-(8,11,10,3)
8. Stress Analysis of bone assembled with Scaffold-(13)
9. Software’s used for designing and analysis of lattice structure-(8,11)
10. Optimization of lattice structure
16

17. Literature Review
S.N Title Remarks Author Year
1. International Journal of Biomaterials -
Next Generation Orthopaedic Implants by
Additive Manufacturing Using Electron
Beam Melting(Review)
•Importance of porosity in next generation
implants is focused .
•Manufacturability of lattice structure by
Additive Manufacturing using electron
beam melting technique reviewed for
Ti6Al4V , and Co-Cr-Mo.
1. Lawrence E.
Murr
2 .Sara M.
Gaytan
2016
2. Materials and Design-Elsevier
Selective laser melting (SLM) of AlSi12Mg
Lattice Structures
•BCC,FCC,BCCZ,FCCZ,FBCCZ truss
based lattice structure are manufactured by
SLM.
•AlSi12Mg is selected as material for SLM.
•Mechanical properties like compressive
stress and young’s modulus are calculated
for different structures
1.Martin Leary
2.Maciej Mazur
2016
3. Journals of Laser Applications-
Mechanical response of TiAl6V4 lattice
structures manufactured by selective
laser melting in quasistatic and dynamic
compression tests
•Detailed compressive testing of SLM
based fbccz lattice structure is
performed.
•Quasistatic and dynamic tests are
performed for analyis of Ti64
1. M. Brandt
2. S. Merkt
2015
17

18. Literature Review
S.N
Title Remarks Author Year
4. Computer Aided Design-
Creation of a unit block library of
architectures for use in assembled scaffold
engineering
•A novel method is showed for creating unit
cell library.
•FEA is performed for Confined
compressive testing of unit cells on
ABAQUS.
1.M.A.Wettergr
een
2.B.S.Bucklen
2005
5. Injury-
Scaffold for bone healing: Concepts,
materials and evidence
•Synthetic Scaffold materials are shown in
this paper.
•Metals, Ceramics, Bioglass , Polymers can
be used as scaffold material.
1.P.Lichte
2.H.C.Pape
2011
6. Injury-
Tissue engineering approaches for bone
repair: Concept and evidences
•Concepts like osteoinduction,
osteocunduction, oseogenicity are
explained .
•How to increase healing process by porous
design is shown
1.JoshE.Schrode
r
2.RamiMosheiff
2011
7. Journal of Manufacturing Processes -
A design for the additive manufacture of
functionally graded porous structures with
tailored mechanical properties for
biomedical applications
•EBM based lattice structure are
manufactured.
•FEA is performed for mechanical
properties.
•Lattice structure is then applied to
orthopaedic implants.
1.Jayanthi
Parthasarathy
2.Binil Starly
3.Shivakumar
Raman
2011
18

19. Literature Review
S.N
.
Title Remarks Author Year
8. Nature- Scientific Reports
In vitro and in vivo study of additive
manufactured porous Ti6Al4V scaffolds for
repairing bone defects
•Diamond type lattice structure is used for
modeling of scaffold. Manufactured by Arcam
EBM machine.
•In vitro and in vivo tests are performed for
manufactured scaffold of Ti6Al4V.
•Bone growth is shown for 3,6,12 months.
1.Guoyuan Li
2. Lei Wang
2016
9. Mechanical Behavior of Biomedical
Materials- Compressive behavior of bovine
cancellous bone and bone analogous
materials, micro CT characterization and
FE analysis
•Micro C.T. is used for modeling bone like
open cellular foam structure .
•FEM is performed on Abaqus for mechanical
testing.
•AlSi7Mg and CuSn12Ni2 materails are used
for manufacturing of foam
1.T.Guillen
2.Q.H.Zhang
2011
10. Cell Press-
Recent advances in bone tissue engineering
scaffolds(Review)
•Critical issues in bone tissue engineering
like- 1.biocompatibility 2. biomechanical
strength 3. Metal ion release 4.
biodegradation 5. Toughness are reviewed for
additive manufactured scaffold
1.Susmita
Bose
2.Mangal Roy
2012
11. Materials Letter-
A novel model for porous scaffold to match
the mechanical anisotropy and structure of
bone
•A novel elliptical type of lattice structure is
designed for getting bone like mechanical
properties. FEA of compressive testing is
performed for validation.
1.Shiping
Huang
2.Zhou Chen
2014
19

20. Literature Review
S.N. Title Remarks Author Year
12. Acta Biomaterialia -
Design and properties of 3D scaffolds
for bone tissue engineering
•Design ,FEA and CFD is performed on 3d
scaffold made by novel Voronoi tessellation
Method.
•Grasshopper is used for Design and Comsol
is used for FEA and CFD.
1.S. Gómez 2.M.D.Vlad 2016
13. Composite Structures -
Effect of structural stiffness of
composite bone plate–scaffold
assembly on tibial fracture with large
fracture gap
•Assembled model of bone and scaffold is
being analyzed in ABAQUS .
•Concept of F.G.M. is used for getting
optimum results.
1. Hassan Mehboob
2.Seung-Hwan Chang
2015
14. ASME-
Stress analysis of bone scaffold
designed for Segmental bone defects
• A honey comb lattice structure is designed
in Solidworks and simulation of compressive
testing is performed.
•Density is changed by changing strut
diameter.
1.Idriss Slaoui 2.Douglas
E.Dow
2015
15. Injury-
The use of bone grafts substitutes in
large bone defects: Any specific
needs?
•Advantages and limitations of autograft and
allograft are explained.
•Necessity, Materials and methods of
manufacturing for synthetic scaffold is
explained.
•Case study for long bone union is given.
1.G.M.Calori
2.E.Mazza
2011
20

21. Conclusion from
Research papers
21

22. Conclusion from Research papers
• Idea of segmental bone defect and present recovery
methods.
• Conceptualization of Next Generation orthopaedic
implants
• Need of lattice structure in bone scaffold
• Design and fabrication of Lattice structures
• Effect of lattice structure geometry on mechanical
properties of scaffold.
• Additive Manufacturing techniques for 3d printing of
lattice structure based implants
22

23. Conceptualization
Segmental
Bone Defect
Scaffold
Design & FEA
Additive
Manufacturing
Bone Implant
in Human
23

24. 1.Design of Lattice
Structure based Scaffold
24

25. Why Lattice Structure?
• In a new way of thinking a real bone like structure can be generated by using
lattice structural properties.
• Lattice structures are light in weight , having porosity , having sufficient
strength to bear the load.
25
Sources: ARCAM EBM

26. Concept of Unit Cells for Lattice
Structure
26
Different types of Unit Cell
Lattice Structure by Unit cell
Ref: Volker Weißmann et.al Specific Yielding of Selective Laser-Melted Ti6Al4V Open-Porous Scaffolds as a Function of Unit Cell
Design and Dimensions Metals 2016, 6, 166; doi:10.3390/met6070166

27. Lattice Structure Generation
• Designing
• FEM Analysis- Mechanical ,Biological
• .Stl file format preparation
• Additive Manufacturing -SLM
• SEM, Micro CT scan
• Testing- Mechanical, Biological-In Vivo, In Vitro
27

28. Designing of lattice structure
• There are four basic methods by which lattice
structure’s are designed –
1. 3d geometric modeling by basic primitives
2. Implicit surface model
3. Image method- micro CT
28

29. Different Types of scaffold Modeling
29Ref:S. Gómez et.al. Design and properties of 3D scaffolds for bone tissue engineering Acta Biomaterialia 42 (2016) 341–350

30. 2. FEA of
Lattice Structure
30

31. Study of Compressive load on Unit
cell
31
Figure: Illustration of finite element method.
(A) Unit block, seen in plane with bottom face fixed in translation in the y direction and the top face
displaced in the y-direction. Subjected to 1% strain at the top face.
(B) Boundary conditions applied to the unit block in the y-direction.
(C) Contour plot of maximum principal stress within the architecture.
Ref:M.A.Wettergreen et.al Creation of a unit block library of architectures for use in assembled scaffold engineering Computer Aided
Design-37-2005 1141-1149

32. Study of Compressive behavior of
Lattice Structure on confined and
unconfined testing conditions
32
Compressive behavior of lattice structure is investigated for confined and unconfined
testing conditions.
Ref: Martin Leary et.al Selective laser melting (SLM) of AlSi12Mg lattice structures Materials and Design 98 (2016) 344–357

33. Investigation of Compressive behavior of scaffold
assembled with bone plate in bone
33Ref: Hassan Mehboob et.al. Effect of structural stiffness of composite bone plate–scaffold assembly on tibial fracture with large fracture gap
Composite Structures 124 (2015) 327–336

34. 3.Additive
Manufacturing
of Lattice Structure
34

35. Additive Manufacturing of scaffold
Additive manufacturing of metals can be done
by mainly three different techniques
1. Selective Laser Melting(SLM)
2. Electron Beam Melting(EBM)
3. Laser Engineered Net Shaping(LENS)
35

36. Metals available for scaffold
These six metals are available for additive
manufacturing of scaffolds.
1. Ti6Al4V(Ti-64)
2. Steel
3. Cu-Co alloy
4. Ni-Ti alloy
5. Tantalum
6. Mg alloy
36

37. 4.Implant in human
body
37

38. Scaffold in Human Body
• In vitro and In vivo tests are performed for
testing of scaffolds .
• Cell proliferation, adhesion,
bio- compatibility , bio- degradability , bone
regeneration are tested.
• Several animal studies are going on for the
test of additively manufactured lattice
structure.
38

39. Idea of My Work-
Objective
39

40. Objective
Designing Part-
• Creation of unit cell library
• Converting unit cells into lattice structure
with different dimensions and orientations
• Calculation of effect of unit block porosity on
mechanical properties like Young’s modulus
for confined and unconfined compressive
testing.
40

41. Objective
FEM Part-
• Compressive loading behavior -Unit cell , lattice
structure
• Bending behavior of lattice structure in a long bone
• Calculation of stress and strain for different unit cells
in confined and unconfined compressive testing.
• FEM simulation of stress distribution, displacement,
reaction force for different unit cells and lattice
structures in confined and unconfined compressive
testing
41

42. References
[1] Martin Leary, Maciej Mazur , Joe Elambasseril , Matthew McMillan , Thomas Chirent , Yingying
Sun , Ma Qian , Mark Easton , Milan Brandt ,Selective laser melting (SLM) of AlSi12Mg lattice
structures, Materials and Design 98 (2016) 344–357
[2] M.A. Wettergreena, B.S. Bucklen, B. Starly, E. Yuksel, W. Sun, M.A.K. Liebschner, Creation of
a unit block library of architectures for use in assembled scaffold engineering, Computer-Aided
Design 37 (2005) 1141–1149
[3] Lawrence E. Murr, Sara M. Gaytan,Edwin Martinez, Frank Medina, and Ryan B. Wicker, Next
Generation Orthopaedic Implants by Additive Manufacturing Using Electron Beam Melting ,
Hindawi Publishing Corporation International Journal of Biomaterials Volume 2012, Article ID
245727, 14 pages doi:10.1155/2012/245727
[4] Volker Weißmann , Jan Wieding , Harald Hansmann , Nico Laufer , Andreas Wolf and Rainer
Bader ,Specific Yielding of Selective Laser-Melted Ti6Al4V Open-Porous Scaffolds as a
Function of Unit Cell Design and Dimensions Metals 2016, 6, 166; doi:10.3390/met6070166
www.mdpi.com/journal/metals
[5] Lawrence E. Murr, Edwin Martinez, Krista N. Amato, Sara M. Gaytan, Jennifer Hernandez, Diana
A. Ramirez, Patrick W. Shindo, Frank Medina, Ryan B. Wicker, (R) Fabrication of Metal and
Alloy Components by Additive Manufacturing: Examples of 3D Materials Science
42

43. References
[6] Jayanthi Parthasarathy ,Binil Starly,Shivakumar Raman A design for the additive manufacture of
functionally graded porous structures with tailored mechanical properties for biomedical
applications Journal of Manufacturing Processes
[7] L. E. Murr, S. M. Gaytan, F. Medina, H. Lopez, E. Martinez, B. I. Machado, D.
H. Hernandez, L. Martinez, M. I. Lopez, R. B. Wicker, J. Bracke Next-generation biomedical implants
using additive manufacturing of complex, cellular and functional mesh arrays Advanced processing
of biomaterials Published 22 March 2010.DOI: 10.1098/rsta.2010.0010 PHYLOSPHICAL Transitions
of Royal Society A
[8] Susmita Bose, Mangal Roy and Amit Bandyopadhyay Recent advances in bone tissue engineering
scaffolds Trends in Biotechnology, October 2012, Vol. 30, No. 10
http://dx.doi.org/10.1016/j.tibtech.2012.07.005
[9] Feng P, Wei P, Shuai C, Peng S (2014) Characterization of Mechanical and Biological Properties of 3-D
Scaffolds Reinforced with Zinc Oxide for Bone Tissue Engineering. PLoS ONE 9(1): e87755.
doi:10.1371/journal.pone.0087755
[10] Garrett Ryan, Abhay Pandit, Dimitrios Panagiotis Apatsidis Fabrication methods of porous metals
for use in orthopaedic applications
Biomaterials 27 (2006) 2651–2670
43

44. Thank You ...
44

45. 45

46. Confined compression testing
46

47. Objective-1
Ref:Image-10
Effect of unit block porosity on apparent mechanical properties
47
•

48. Objective-2
Uniaxial compression stress-strain responses of tested lattice specimens.
Ref: Figure-11
48

49. Objective-3
49
Figure:12

50. Surface Name
• NS- Neovius Surface
• SP- Schwarz primitive
• SD- Schwarz Diamond
• SG- Schwarz Gyroid
• SW- Schwarz W
50