|dc.description.abstract||This thesis is focussed on a numerical method to analyse the ballistic performance
of multi-material armour system. The overall objective of this work is to develop
numerical models to be used within MSC. DYTRAN capable of accurately predicting
the ballistic response of multi-material composite armour, the effect of impact type
on the damage and to help improve the armour design.
The research presented in this thesis includes a review of the existing ceramic and
composite damage models, combine, modify and optimize them to investigate the
type and extent of damage response of the materials used in ballistic protection.
The numerical model leads to insight into the parameters governing the penetration
and deformation response of laminated composite subjected to ballistic impact. The
effect of various model parameters on the predicted ballistic response of the
ballistic plate is intensively investigated. It was found that the through thickness
properties used in the numerical model have a large effect on the predicted ballistic
A detailed study of the effect of mesh density on the numerical solution has shown
that the numerical predictions are highly influenced by the element shape and size.
The smaller the element the sooner the failure occurs, the less energy is absorbed
and the smaller the time step becomes leading to a larger simulation time.
The accuracy of the composite numerical model was evaluated by comparing the
numerical prediction to experimental data obtained from ballistic impact trials.
Very good agreement has been found between the experimental and numerical
results for both observations of damage and deformation. Further, values of
measured ballistic limit are in very good agreement with the values gained from the
simulations. This correlation forms a verification of our finite element simulations.
Fibre breakage is generally acknowledged as the main energy absorption
mechanism in damage due to ballistic impact; in this work the delamination and
matrix failure have been shown to increasingly contribute to the energy absorption
mechanism by reducing the matrix strength.
Further study of multi-layered ceramic composite armour has shown that use of
ceramic tiles can improve the ballistic protection of the armour within an optimum
ceramic composite ratio.
Finite element simulation has been shown to be a very powerful technique to
predict the behaviour of composite and ceramic panels under ballistic impact.||en_US