|dc.description.abstract||Among the issues that are taken into consideration for many years by Engineers
and Technologists is the integrity of the servicing elements in structures and
mechanisms. It is a documented phenomenon that after a certain period of time, in
service, engineering components tend to change their original state, and begin to
develop faults and defects. This includes the original shape distortion due to
effects such as bending, twisting, and cracks. The above-sited effects may be
caused by the sudden or accumulative effect of overloading, thermal shocks,
corrosion etc, which eventually lead to malfunction of these engineering
The occurrence of the cracks may be as a result of stress variation in excess of
different or similar materials; thermal shocks, vibration, etc.
A system of structural health monitoring using optical fiber sensors to track down a
crack occurrence and its propagation is considered to be a promising method in
warning of catastrophic events.
Taking advantage of optical fibers' properties and behavior, such as easy
interaction with other materials, small size, low weight, corrosion resistance,
geometrical flexibility and an inherent immunity to electromagnetic interference,
there is potential in adopting the Fiber Optic Sensors (FOS) for structural health
Structural integrity does not confine itself to crack detection only. For example
there are many instances where unwanted or excessive displacement may occur.
Optical fibers play an important role in proximity sensing as evidenced in the
literature  to  and available commercial systems.
However it is felt that FOS displacement sensors may suffer in measurement
accuracy due to in situ conditions.||