Effect of frequency on the failure of articular cartilage

Sadeghi, Hamid (2017). Effect of frequency on the failure of articular cartilage. University of Birmingham. Ph.D.

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Articular cartilage in synovial joints can become damaged due to mechanical loading, trauma or wear and tear. The initiation and progression of damage in cartilage may lead to degenerative changes of the joint. However, links between mechanical loading and the initiation/progression of damage in cartilage remain poorly understood.
In this thesis, the damaging effects of loading frequencies representative of normal (1 Hz), above normal (10Hz) and rapid heel-strikes (100Hz) on cartilage/cartilage-on-bone were assessed and compared to
test the hypothesis that failure can be influenced by frequency. Bovine cartilage was used as a model for human
cartilage. Materials testing machines were used to apply sinusoidally varying loads at different frequencies and
altered maximum forces under different loading types. A metal indenter was used to apply cyclic loading on
cartilage-on-bone specimens to produce failure on the surface of cartilage-on-bone specimens in compression.
Fatigue failure of cartilage-on-bone specimens were determined using cyclic three-point bending. Propagation
of an initial crack across the area of cartilage specimens with respect to increasing number of loading cycles were measured and compared under tension.
The results from this thesis indicated that failure increases significantly (p < 0.05) in cartilage-on-bone
specimens with increasing the loading frequency under compression and bending. Strain experienced by the
cartilage specimens at higher frequency, e.g. 100 Hz, caused a greater crack growth under tension. The results
from this work have many potential implications in the early onset of osteoarthritis. This is because rapid heel-strike rise times have been implicated in the early onset of osteoarthritis.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Engineering
Funders: None/not applicable
Subjects: Q Science > QM Human anatomy
URI: http://etheses.bham.ac.uk/id/eprint/7616


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