Vehicular armour

Armour for a vehicle comprises ceramic plates (3, 4) with a spall covering (5) on a front surface of the ceramic plate (3), the ceramic plate (4) being bonded at a rear surface thereof to a stiff support plate (2), a plastically deformable layers (9, 10) arranged behind the support plate (2), and spacing means (7) defining a front substantially planar space (11) between the support plate (2) and the plastically deformable layer (9) and a rear substantially planar space (14) arranged to be located between the plastically deformable layer (10) and a vehicle hull (13).

This invention relates to armour for a vehicle.

WO 03/010484 describes a ceramic armour system for a vehicle including a ceramic plate comprising alternate layers of different ceramic materials. A front spall layer is bonded to the front surface of the ceramic plate, and a rear shock-absorbing layer is bonded to the rear surface thereof. The assembly may be bolted to the hull of a vehicle with an air gap.

The present invention seeks to provide an armour panel with improved resistance to high-speed fragments of the type capable of penetrating extremely thick steel armour plate.

The invention provides vehicle armour comprising a ceramic plate with a spall covering on a front surface of the ceramic plate, the ceramic plate being bonded at a rear surface thereof to a stiff support plate, a plastically deformable layer arranged behind the support plate, and spacing means defining a front substantially planar space between the support plate and the plastically deformable layer and a rear substantially planar space arranged to be located between the plastically deformable layer and a vehicle hull.

We have found that such a plastically deformable layer can decelerate fragments penetrating the ceramic plate and the support plate.

The ceramic plate may comprise at least two ceramic layers bonded together, for example one layer of ceramic material with good hardness and fracture toughness or good thermal properties and a second layer with good ballistic properties.

The spall covering may be of a thermoplastic material such as polycarbonate and may extend not only over the front surface of the ceramic plate but also over its edges, its rear surface and/or between any ceramic layers from which the ceramic plate is formed.

In one embodiment, the support plate is of a composite material, e.g. comprising carbon or glass.

The ceramic plate may be bonded to the support plate using an elastomeric material, e.g. polyurethane, which may cover all outer surfaces of the ceramic plate with its spall cover.

An embodiment of the invention includes a rear plastically deformable layer arranged behind said plastically deformable layer that is arranged behind the support plate, the spacing means defining an intermediate space between the two plastically deformable layers.

The or each plastically deformable layer can be formed from a multiplicity of laminations. Low-density plastics such as polyethylene are suitable for forming the or each plastically deformable layer.

In embodiments of the invention, at least one of the front, rear and intermediate spaces contain(s) crushable foam such as polyethylene. This helps to ensure that the movement or deformation of the ceramic plate and/or the plastically deformable area is more uniform across the entire protected area.

The invention provides armour of low areal density, e.g. one third to one half that of known steel vehicle armour.

The drawings show a square panel comprising a ceramic plate assembly1bonded to a support plate2of slightly greater area than the assembly1. The assembly1comprises two ceramic plates3,4with a layer of polycarbonate5extending around all surfaces of the plates, and is obtainable from Aceram Technologies, Inc. of Kingston, Ontario.

The assembly1is bonded to the support plate with an elastomeric, e.g. polyurethane-based adhesive, which may completely surround the assembly1.

In this example, the support plate2is of a carbon fibre/epoxy composite and has holes adjacent each of its corners. Spacing rods7, e.g. aluminium tubes, extend through the holes, e.g. with a force fit, and the plate2is retained on the rods by nuts8.

The rods7also extend through front and rear plastically deformable plates9,10. These may be of laminated ultra high molecular weight polyethylene, e.g. “Dyneema”® from DSM Dyneema of Geelen, Netherlands, or another suitable polymer.

The rods maintain a front air gap11between support plate2and front deformable plate9and an intermediate air gap12between front deformable plate9and rear deformable plate10. The rods7also serve to secure the panel to a vehicle hull13(shown in section), with a rear air gap14between the rear deformable plate and the hull13. For example, the front and intermediate gaps may each have a thickness of 10 to 15 mm, whilst the rear air gap is substantially thicker. The rear gap14has a thickness allowing the deformable plates9,10to deform and catch the fragments after the assembly1and support plate2have damaged them. The rear gap thickness could for example be from about 100 mm to about 150 mm. In this regard, a thicker gap increases protection, but there is usually a maximum vehicle width that cannot be exceeded.