The objective of the present M.Sc thesis is to propose a design for a blast resistant armour
floor panel for vehicles in military applications. The project is conducted in cooperation
with Composhield A/S, a military armour manufacturer, who aim to enhance their already
extensive product portfolio within lightweight protection panels supplying greater
protection of their clients in theatres of operation around the world. The proposed design
is an amour floor panel with specifications offering protection against a blast load from an
explosive placed directly beneath the vehicle of equivalent 0,12 kg TNT at a distance of 0,5
m, i.e. the case-load. The panel does resist greater blast loads with slight modifications.
A three-way approach to the problem is taken consisting of an analytical, a numerical and
an experimental approach. Only the analytical and numerical approach are finished in
the following report, while the experimental approach is planned for the near future. The
analytical approach is utilised for obtaining a solid understanding of the governing blast
parameters and an initial guess of different design parameters. This approach is mainly
academical. The actual design of the armour panel is conducted purely numerically.
One of the significant problems in the thesis is to determine or quantify the blast load
acting on the floor of the vehicle originating from an exploding DM51 hand grenade of 0,12
kg TNT at a distance of 0,5 m. An extensive study of blast effects is therefore conducted in
order to determine the design load on the structure acting as a load case for the remaining
of the project. This is followed by a study of the material parameters of foamed aluminium
in order to determine the energy absorbing properties and ultimately the applicability
in armour panels. Analytical studies in determining the deformation and the optimum
distribution of front panel and foam mass for maximum energy absorption are conducted.
However, the manufacturing methods of aluminium foams are very difficult to control
while remaining cheap resulting in a, at times, highly inhomogeneous material which is
unacceptable in some applications. An alternative using a lattice structure is therefore
investigated, resulting in a highly modifiable structure which can be re-engineered for
specific needs.
A numerical design procedure using hydrocode is utilised in search of a capable design
concept for blast loads which is the main focus of the thesis. The capable design is
reached through a parametric study of multiple iterations minimising the residual load in
the structure following the deformation of the armour panel.
The experimental approach has not been conducted, but a plan for near future experimental
work is described in the report. This includes verification of discrepancies between the
analytical and numerical approach, and a full-scale test of the armour panel for validation
of the ability of the panel to withstand the specified blast threat.