
342 Computational Modelling of Biomechanics and Biotribology
11.3.8 Fragility
The use of ceramic for implants has many advantages, but it is a fragile mate-
rial. The degree of its fragility k (used for other materials as well) is de ned
by the ratio of tensile strength, R
m
, to compressive strength, R
c
:
R
[11.7]
If k < 1/8 , the material is classi ed as fragile.
11.3.9 Abrasion
Due to high hardness, ceramic and reinforced metal alloys are used in a
number of cooperating components subject to abrasion (e.g., in endopros-
theses). An abrasion test measures the sample weight loss during grinding
on a rotating grinding ...