Fracture of Biomaterials

1
Fracture of Biomaterials
Brittle
Ductile
2
Griffith model Assumes a pre-existing flaw
s
Eliptical flaw
L
2c
s
Total energy U -pc2s2L/E 4?cL Crack
propagates if s v (2 ?E/pc)
3
Nacre shell fracture surface
4
Mineralized Tissues Dental Enamel
Enamel
Dentin
Pulp
Gingiva
Alveolar Bone
Cementum
Periodontal Membrane
5
Enamel Structure
1
2
5
1
4
3
5
2
3
4
6
Mineralized Tissues - Bone
(b)
(a)
100 µm
(c)
0.1 µm
cm to m
7
Multi-Scale Structure of Bone
(e)
(d)
nm
nm
(f)
Å