The thesis describes a series of experiments using a split
Hopkinson pressure bar to study the mechanical behaviour of a carbon
fibre composite at high rates of loading.
The split Hopkinson pressure bar technique uses specimens in the
form of a cylinder, sandwiched between two steel bars of the same
diameter,as the specimen. Ona of the steel bars is subjected to an
impact produced by a projectile from a gas gun specifically
developed for this purpose. This produces a stress pulse incident
on the specimen which will produce stresses within the specimen of
up to 3 x 108 N/m2 with rise times of approximately 15 to 30 micro
seconds. The study of material behaviour at these strain rates
involves the study of stress wave propagation.
The thesis initially discusses the theory of stress wave propagation
and then gives a brief history of the Hopkinson pressure bar. The
configuration used for this particular series of experiments is
described and an account is given of its use to compare two different
techniques of monitoring specimen behaviour. These were an optical
and a strain gauge method. (...continues)
A Master's Dissertation, submitted in partial fulfilment of the requirements of the award of the Master Of Science degree of Loughborough University.