Samenvatting
With the current events concerning terrorist attacks, it is imperative toperform research and development on issues related to ballistic protection.
The need to protect soldiers from high impact velocity threats has become
increasingly important and challenging. Within the scope of this work the
aim is to develop an optimised armour configuration for an advanced ballistic
helmet design, which is able to defeat impacts from high velocity rifle bullets. This is done using finite element modelling supported by results from experimental tests. The design presented here is based on four different layers, where: (i) the first layer is designed to break and erode the projectile, (ii) the second layer absorbs the kinetic energy of the projectile, (iii) the third layer minimises the back face deflection and, finally, (iv) a fourth layer absorbs the shock wave of the initial impact and provides the necessary standoff (required by the back face deflection) for the first three layers, so that direct contact between these layers and the head does not occur. The results obtained by simulation with the finite element method
(using LS-DynaTM) demonstrate that the models agree with the experimental
results. A detailed numerical study of the different layers as well as
the 7.62 x 39 M43 projectile was made. A good correlation between numerical and experimental results of the ammunition and armour materials was achieved, as well as between numerical and experimental results in terms of the depth of indentation as a function of impact velocity of the new ballistic helmet design. The last two sets of numerical analysis made for the helmet shell configuration was relative to the shock absorbing layer. The first set of simulations consisted of introducing rigid boundaries to the composite layer of the at panel. A second set of simulations considered the composite layer of the at panel to be attached to a rigid frame, without fixing this frame. From the simulation results, a shock-absorbing layer can be designed in such a way as to significantly reduce the risk on behind-helmet blunt trauma, and with acceptable force transfer to the head. An optimum standoff distance was determined for a ballistic helmet concept able to stop the M43 Kalashnikov projectile.
Datum prijs | feb. 2020 |
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Originele taal | Engels |
Begeleider | Frederik Coghe (Promotor) & Filipe Teixeira-Dias (Promotor) |