An investigation into methods to enhance the interlaminar
shear strength of continuous fibre reinforced ceramics

Abstract: This Master Thesis investigates the possibility to implement new innovative
textile techniques for the manufacturing of fibre reinforced ceramics with
the purpose of enhancing the interlaminar properties.

A needling technique is developed that pushes fibre material into and
through a laminate, creating a 3-dimensional structure. This results in a
stable structure that is suitable as a preform onto which a non-oxide ceramic
matrix such as graphite or silicon carbide can be placed using a vapour
deposition or vapour infiltration process.

By manufacturing specimens made of unidirectional carbon fabrics and an
epoxy matrix, the crack initiation and propagation during destructive testing
is analysed. The study shows that the failure mechanism for such a needled
material is changed during bending loads. This is due to the modification of
the fibre structure that creates through the thickness fibres. It is
demonstrated that it is possible to increase the energy absorption and the
fracture toughness of the needled material.

In addition, an electrostatic flocking procedure for creating interlaminar
fibres is investigated using electromagnetic field theory combined with
numerical analysis. Via theory and conventional techniques a manufacturing
procedure for flocked material is developed and shown to display great
potential for increasing interlaminar shear strength of any laminated
fibre-reinforced material.

Finally, the possibility to implement the above techniques into industry and
the methods to do so is demonstrated.