WO1998030772A1

WO1998030772A1 - Panel constructions

Info

Publication number: WO1998030772A1
Application number: PCT/GB1998/000056
Authority: WO
Inventors: Kenneth Shemwell
Original assignee: British Steel PLC
Current assignee: British Steel PLC
Priority date: 1997-01-11
Filing date: 1998-01-09
Publication date: 1998-07-16
Anticipated expiration: 1999-07-11
Also published as: GB9700519D0; AU5566098A

Abstract

The application describes a panel structure for absorbing a shock wave or other impact, comprising a front plate (10), a rear planar member (12), and a honeycomb array between the front plate (10) and rear planar member (12), a substantial number of the honeycomb cells (14) being sealed at either end. The honeycomb members (14) are preferably tubular, and are more preferably adhesively bonded in place to the front and back plates (10, 12). Equally preferably, they can be bonded to each other with a suitable adhesive. In a preferred form of the invention, each or at least a substantial number of the honeycomb cells (14) contain an intermediate seal dividing the sealed honeycomb cell (14) into a first cell portion proximate the front plate (10) and a second cell (14) portion proximate the black plate (12). More preferably, each or at least a substantial number of the honeycomb cells (14) are formed from two sealed tubular (or other prismatic) members fixed end to end, thus forming the single cell with an intermediate seal. Each tubular member is preferably sealed prior to connection. The ends of tubular members can be shaped so as to provide an interlocking structure. The rear planar member (12) can be an external face of a large flat object, such as a wall. Where the panel is freestanding, or may be moved between installations, it is preferred if the rear planar member (12) is a back plate behind the honeycomb array. The front plate (10) and/or the back plate (12) (where provided), and more preferably both, can be made from steel such as a mild steel. It is preferred if the front plate (10), i.e. that facing the likely site of the explosion, is of a heavier gauge than the rear plate. The honeycomb members (14) are suitably also of steel such as mild steel. The honeycomb members (14) can be formed in a hexagonal close packed array, since this is usually the easier to construct. However, it may be preferable for there to be a gap between adjacent honeycomb cells (14). The gap is preferably less than the diameter of the honeycomb cells (14).

Description

PANEL CONSTRUCTIONS

The present invention relates to a panel construction. The panel construction according to the present invention is particularly useful for absorbing impacts and (particularly) shock waves such as may be produced in the vicinity of an explosion.

There are two general approaches to the protection of items from an explosion. The first is to provide armour plating and/or substantial covering structures which are sufficiently strong to deflect the energy of the explosion. Such structures can be used repeatedly, but are large, bulky and expensive. The second approach is to provide a structure which will deform in a limited and predictable manner thereby absorbing the energy of the explosion. Such structures can only be relied upon once, but can often be less bulky and expensive and may well provide adequate protection from a larger explosion.

Known blast absorbing structures include a honeycomb filled with plastics foam, a plaster or cement wall containing vermiculite particles, and the like.

The present invention provides a panel structure for absorbing a shock wave or other impact, comprising a front plate, a rear planar member, and a honeycomb array between the front plate and rear planar member, a substantial number of the honeycomb cells being sealed at either end. The honeycomb members are preferably tubular, and are more preferably adhesively bonded in place to the front and back plates. Equally preferably, they can be bonded to each other with a suitable adhesive.

In a preferred form of the invention, each or at least a substantial number of the honeycomb cells contain an intermediate seal dividing the sealed honeycomb cell into a first cell portion proximate the front plate and a second cell portion proximate the back plate.

More preferably, each or at least a substantial number of the honeycomb cells are formed from two sealed tubular (or other prismatic) members fixed end to end, thus forming the single cell with an intermediate seal. Each tubular member is preferably sealed prior to connection. The ends of tubular members can be shaped so as to provide an interlocking structure.

Preferably, all of the honeycomb members are as set out above, subject only to manufacturing errors.

The rear planar member can be an external face of a large flat object, such as a wall. Where the panel is free-standing, or may be moved between installations, it is preferred if the rear planar member is a back plate behind the honeycomb array.

The front plate and/or the back plate (where provided) , and more preferably both, can be made from steel such as a mild steel. It is preferred if the front plate, ie that facing the likely site of the explosion, is of a heavier gauge than the rear plate. The honeycomb members are suitably also of steel such as mild steel.

The honeycomb members can be formed in an hexagonal close packed array, since this is usually the easier to construct. However, it may be preferable for there to be a gap between adjacent honeycomb cells. The gap is preferably less than the diameter of the honeycomb cells.

An embodiment of the present invention will now be described by way of example, with reference to the accompanying Figures, in which:-

Figure 1 shows a cross-sectional view through a panel according to a first embodiment of the present invention, taken on lines l-l of Figure 2; and

Figure 2 shows a front cross-sectional view of the panel of Figure 1 , taken along ll-ll of Figure 1 ; and

Figure 3 shows a cross-sectional view through a second embodiment of the present invention.

Referring to Figures 1 and 2, the panel of the first embodiment of the present invention comprises a front plate 1 0 and a rear plate 1 2. A double layer of sealed cylindrical cells 1 4 is sandwiched between the plates 1 0, 1 2. Each cylindrical cell has a circumferential outer ridge 1 6 at one end and an inwardly displaced ridge 1 8 at the other, such that adjacent cells situated end to end will interlock slightly with the inner ridge 1 8 of one cell sitting within the outer ridge 1 6 of the other. Thus, an axially aligned pair of cells define a honeycomb cell with a first cell portion 22 and a second cell portion 24 and an intermediate seal 26 therebetween.

The cells 1 4 are held in place by bonding with a polyurethane resin adhesive. The front and back plate 1 0, 1 2 are then bonded over the honeycomb structure, also using polyurethane resin.

After construction of the panel, transit bars 20 are welded to the edges of the front and rear plates 1 0, 1 2 to maintain the front and rear plates 10, 1 2 in fixed relationship during delivery and thereby prevent any unintended damage to the honeycomb structure. These transit bars are removed or cut once the structure is in position.

As shown in Figure 1 , the front plate 1 0 is thicker than the rear plate 1 2.

Once installed, the structure to be protected from a blast is placed behind the rear plate 1 2. The plate structure is useful for protecting such structures as buildings, in which case it can be placed against an external wall, and free standing structures, in which case the item is substantially surrounded with vertically disposed panels. When the front plate 1 0 is subjected to a shock wave, the energy of the shock wave is taken up as an acceleration of the front plate 1 0 which is then projected rearwardly towards the rear plate 1 2. This causes the honeycomb cells 1 4 to be crushed longitudinally, absorbing the energy via plastic deformation. It has been found that the double layer of cells 1 4 in combination with the front and rear plates 1 0, 1 2 provides a significantly better blast absorption than a single layer.

The volume of the cells 1 4 is preferably between 200 and 400 ml, preferably about 330 ml. Indeed, it has been discovered that steel soft drink cans such as those marketed by the applicant under the trade mark ECOTOP are eminently suitable in that they provide a sealed space of suitable volume and are easy to manufacture in large quantities. The wall thickness is suitably about 0.1 mm.

Figurers 1 and 2 show a hexagonal close packed array of cells 1 4. It may be that a gap between each cell will provide better performance in that longitudinal buckling of the cell will be facilitated . However, there is inevitably a balance in that as the gap is increased the number of ceils to perform energy absorption will be decreased. In certain situations, fewer cans may be sufficient to absorb an anticipated shock. It is not expected that a gap greater than the width of the cell will be taken up during deformation of the cell, it is preferred that the gap is not greater than twice the width of the cells.

A suitable thickness of the front and rear plate is 1 1 mm thick for the front plate and 6mm thick for the rear plate. Mild steel is suitable.

Although Figures 1 and 2 show a double row of cells, more rows could be provided.

The panel according to the invention can be used in a wide variety of situations. For example, it can be placed against the wall of a building, or beneath the underside of a vehicle. It will be evident that the dimensions of the panel will need to be adjusted in these cases.

Figure 3 shows a panel according to a second embodiment of the present invention, used to protect a wall 1 1 2 from a Shockwave. The construction is generally similar to the panel of Figure 1 , except that the transit bars 20 are removed, the article having been positioned in place, and the rear plate 1 2 is omitted. Thus, the rear layer of the honeycomb cells 1 1 4 abuts against the front face of the wall 1 1 2. The wall 1 1 2 and the front plate 1 1 0 both rest on the ground surface 1 28, although front plate 1 1 0 is not fixed to the ground 1 28.

It will be appreciated by those skilled in the art that the above described embodiment is given by way of example only and that many variations such as those set out above can be made without departing from the scope of the present invention.

Claims

1 . A panel structure for absorbing a shock wave or other impact, comprising a front plate, a rear planar member, and a honeycomb array between the front plate and rear planar member, a substantial number of the honeycomb cells being sealed at either end.

2. A panel structure according to claim 1 wherein the honeycomb members are tubular.

3. A panel structure according to claim 1 or claim 2 wherein the honeycomb members are adhesively bonded in place to the front and back plates.

4. A panel structure according to any preceding claim wherein the honeycomb members are bonded to each other.

5. A panel structure according to any preceding claim wherein each or at least a substantial number of the honeycomb cells contain an intermediate seal dividing the sealed honeycomb cell into a first cell portion proximate the front plate and a second cell portion proximate the back plate.

6. A panel structure according to claim 5 wherein each or at least a substantial number of the honeycomb cells are formed from two sealed prismatic members fixed end to end, thus forming the single cell with an intermediate seal.

7. A panel structure according to claim 6 wherein the prismatic members are tubular.

8. A panel structure according to claim 6 or claim 7 wherein the prismatic or tubular member is sealed prior to connection.

9. A panel structure according to claim 6 or claim 7 wherein the prismatic or tubular members are shaped so as to provide an interlocking structure.

1 0. A panel structure according to any one of the preceding claims wherein all of the honeycomb members are as set out above, subject only to manufacturing errors.

1 1 . A panel structure according to any preceding claim wherein the rear planar member is an external face of another object.

1 2. A panel structure according to claim 1 1 wherein the other object is a wall.

1 3. A panel structure according to any preceding claim, wherein the front plate and/or the back plate (where provided) are made from steel.

1 4. A panel structure according to claim 1 3 wherein the front plate is of a heavier gauge than the rear plate.

1 5. A panel structure according to any preceding claim wherein the honeycomb members are of steel.

1 6. A panel structure according to any preceding claim wherein the honeycomb members are formed in an hexagonal array.

1 7. A panel structure according to claim 1 6 wherein the hexagonal array is close packed.

1 8. A panel structure according to claim 1 6 wherein the hexagonal array is spaced such that the gap between adjacent honeycomb cells is less than the diameter of the honeycomb cells.

9. A panel structure substantially as herein described with reference to and/or as illustrated in the accompanying drawings.