GB2587209A

GB2587209A - Composite material panels

Info

Publication number: GB2587209A
Application number: GB1913438.6A
Authority: GB
Inventors: Dewhirst Michael
Original assignee: Lentus Composites Ltd
Current assignee: Lentus Composites Ltd
Priority date: 2019-09-18
Filing date: 2019-09-18
Publication date: 2021-03-24
Also published as: GB201913438D0

Abstract

A composite material panel arrangement comprises first and second composite material panels 12, 14 each including a plurality of loops 16 of a reinforcing fibre and being formed with first and second openings 18 at least partly surrounded by at least one of the said loops 16; the first and second openings being aligned with one another, and a fastener member 20 extending through the openings 18, the fastener preferably being encircled by the reinforcing fibre material forming the loops 16 of the first and second panels and/or preferably being of a type that when fastened is of increased diameter relative to the diameter prior to fastening, such as a rivet.. Preferably, each is provided with a plurality of openings which may be arranged in a line. The panels may comprise a sheet of plastics material, such as a glass reinforced plastics material wherein the reinforcing fibre may be carbon fibre laid onto a surface of the panel before curing. With such an arrangement, the fastener is able to transmit loads between the reinforcing fibre loops of the first and second panel.

Description

COMPOSITE MATERIAL PANELS

This invention relates to composite material panels, and in particular to the interconnection of fibre reinforced composite material panels to form panel assemblies of increased surface area, and of good load bearing and load transmitting properties.

The use of composite materials is increasingly common in a wide range of applications, in part because materials of this type are typically of good strength and low weight, and so their use in a number of applications is advantageous. There is a need to provide an arrangement whereby panels of such materials can be connected to one another in a simple and convenient manner in such a manner that a load can be transmitted across the joint between a first one of the panels and a second one of the panels. In is an object of the invention to provide such an arrangement.

According to a first aspect of the invention there is provided a composite material panel arrangement comprising a first composite material panel including a plurality of loops of a reinforcing fibre, a second composite material panel including a plurality of loops of a reinforcing fibre, the first panel being formed with a first opening at least partly surrounded by at least one of the said loops, the second panel being formed with a second opening at least partly surrounded by at least one of the said loops, the first and second openings being aligned with one another, and a fastener member extending through the first and second openings, the fastener being encircled by the reinforcing fibre material forming the loops of the first and second panels.

The fastener may be of a type that when fastened is of increased diameter relative to the diameter prior to fastening.

According to a second aspect of the invention there is provided a composite material panel arrangement comprising a first composite material panel including a plurality of loops of a reinforcing fibre, a second composite material panel including a plurality of loops of a reinforcing fibre, the first panel being formed with a first opening at least partly surrounded by at least one of the said loops, the second panel being formed with a second opening at least partly surrounded by at least one of the said loops, the first and second openings being aligned with one another, and a fastener member extending through the first and second openings, the fastener being of a type that when fastened is of increased diameter relative to the diameter prior to fastening.

It will be appreciated that, in such an arrangement, the fastener is able to transmit loads between the reinforcing fibre loops of the first panel and the reinforcing fibre loops of the second panel. The arrangement thus includes first and second panels interconnected in such a manner that loads are able to be transmitted therebetween.

The first panel may include a plurality of first openings, each being at least partly surrounded by at least one of the said loops, and each being aligned with a respective second opening of the second panel. The first openings may be arranged in a line, if desired, with the second openings similarly being arranged in a line. As each of the first and second openings is at least partially surrounded by a respective loop, it will be appreciated that the arrangement of the openings in a line does not tend to result in the formation of a perforated line of weakness in each of the panels, as may be the case if the openings were not at least partially surrounded by respective ones of the loops.

By using a fastener of the type that expands in diameter upon fastening, it will be appreciated that the fastener can serve to prestress or tension the loops with which it is associated upon fastening and expansion thereof. Such prestressing or tensioning can be used to ensure that, in use, relative movement between the first and second panels is prevented or restricted.

The fastener conveniently takes the form of rivet. However, other forms of fastener that expand radially upon fastening could be used. By way of example, a fastener comprising a threaded nut and bolt with an expansion element held captive upon the shank of the bolt and arranged such that axial compression thereof causes radial expansion thereof could be used, if desired.

The first and/or second panel may comprise, for example, a sheet of a plastics material in or on which are provided the loops of a reinforcing fibre, such as carbon fibre or the like. The plastics material of the panel could comprise, for example, glass fibre reinforced plastics materials.

The panels may be designed in such a manner as to define abutment features, restricting relative movement between the panels, the prestressing or tensioning resulting in an end of one of the panels firmly abutting the abutment feature of the other of the panels.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a view illustrating a composite panel arrangement in accordance with an embodiment of the invention; Figure 2 is a sectional view illustrating part of the arrangement of Figure 1; Figure 3 is a view illustrating part of the arrangement of Figure 1; Figures 4 to 7 are views illustrating steps in the assembly process; and Figures 8 to 12 illustrate alternatives to the arrangement of Figures 1 to 7.

Referring firstly to Figures 1 to 7, a composite material panel arrangement 10 is illustrated which comprises a first panel 12 and a second panel 14, each of which is of composite material form.

By way of example, each of the panels 12, 14 may be of a glass reinforced plastics material. It will be appreciated, however, that the invention is not restricted in this regard and that other materials may be used, if desired, the selection of material being dependent upon, for example, the requirements of the application in which the invention is to be employed.

Applied to a surface of each of the panels 12, 14 are a series of reinforcement fibre material loops 16. As illustrated, each loop 16 is formed by laying down a first elongate run 16a of the fibre material, at an end of the run 16a, laying down an arcuate part 16b, then laying down a second elongate run 16c that extends parallel to but spaced from the first run 16a, and then laying down a second arcuate part 16d. This process is repeated a number of times to form the finished loop 16. Adjacent each of the arcuate parts 16b, an opening 18 is formed in the panel 12, 14, and it will be appreciated that the opening 18 is partially surrounded by the reinforcing fibre material of the loop 16.

In the arrangement shown, the loops 16 are arranged substantially parallel to one another, and are positioned so that the openings 18 of each panel 12, 14 are arranged in a straight line.

However, it will be understood that this need not always be the case.

The openings 18 formed in the panels 12, 14 are positioned so that when the end parts of the panels 12, 14 are overlaid, the openings 18 of the first panel 12 are aligned with the openings 18 of the second panel 14. Once so positioned, fasteners 20 are inserted into each aligned pair of openings 18, as shown in Figures 4 and 5. It will be appreciated that each fastener 20 is completely encircled by the combination of the reinforcing fibres of the associated loops 16 provided in the first and second panels 12, 16.

The fasteners 20, in this embodiment, take the form of rivets designed in such a manner that, during fastening, the diameter of a shank 20a thereof is increased. Accordingly, as shown in Figures 4 and 5, a bush 20b formed at one end of the shank 20a of the rivet bear against a face of the second panel 14. The crimping action of tensioning a stem 20c extending through the shank 20a to fasten the rivet 20 in position causes the deformation of an end part of the shank 20a thereof to form a second bush 20d (see Figure 7) that engages a surface of the first panel 12. The rivet thus serves to apply a compressive load to the panels 12, 14, compressing the interengaged faces of the first and second panels 12, 14 against one another. In addition, and importantly, the crimping action causes the part of the shank 20a intermediate the bushes 20b, 20c to expand radially, before the stem 20c snaps to finish fitting of the rivet. Accordingly, in the orientation shown in Figure 2, the radial expansion of the shank 20a of the rivet, in conjunction with its interaction with the loops 16 of reinforcing fibres surrounding the opening 18, causes the first panel 12 to be urged to the left and the second panel 14 to be urged to the right. This preload serves to assist in ensuring that, in use, relative movement between the first and second panels, resulting from, for example, thermal expansion, vibrations and mechanical loadings, is resisted or avoided, and allows relatively large loadings to be transmitted across the connection between the adjacent panels 12, 14.

Figures 8 and 9 illustrate a modification to the arrangement of Figures 1 to 7 in which the panels 12, 14 are each shaped to define an abutment step 22, the steps 22 being positioned such that an end of the first panel 12 can abut the step 22 of the second panel 14, and the end of the second panel 14 can abut the step 22 of the first panel. After insertion and fastening of the fasteners 20, it will be appreciated that the radial prestressing or tensioning achieved through the use of the radially expanding fasteners results in the end of the first panel 12 being positively forced against the step 22 of the second panel 14, and the end of the second panel 14 being positively forced against the step 22 of the first panel 12. Accordingly, relative movement between the first and second panels 12, 14 is further restricted or avoided.

Figure 10 illustrates a modification to the arrangement shown in Figures 8 and 9 in which only part of the end faces of the panels 12, 14 engage the respective steps 22.

Whilst in the arrangements described hereinbefore, it is envisaged that the first and second panels 12, 14 will both be of relatively large dimensions, it will be appreciated that this need not always be the case and that, as shown in Figure 11, the second one of the panels 14 could comprise a connecting strip that, in addition to be connected to the first panel 12, is also connected to a third panel 24. The ends of the first and third panels 12, 24 may abut one another, and the prestressing or tensioning achieved through the use of the fasteners 20 may positively force the ends of the first and third panels 12, 24 against one another, restricting or preventing relative movement therebetween.

Whilst in the arrangements described hereinbefore the loops 16 are envisaged to extend parallel to an axis of the panels 12, 14, this need not be the case and they could be angled relative thereof, for example to suit an application in which the invention is to be used. By way of example, as shown in Figure 12, the loops could be angled to such an axis. Indeed, again as shown in Figure 12, several layers or sets of loops 16 may be provided at different angles. In the arrangement of Figure 12, the loops 16 that extend generally parallel to the axis will primarily be responsible for transmitting axially directed loads, whereas those that are angled to the axis, for example at 45degrees relative thereto, may be better suited to the transmission of shear loadings.

It will be appreciated that the description hereinbefore is merely of example embodiments of the invention, and that the scope of the invention is not restricted thereto but rather covers a range of modifications and alterations falling within the scope of the appended claims. By way of example, the panels 12, 14 could be of a wide range of materials including but not restricted to planar composite materials, woven prepreg materials, stitched textile materials impregnated with a resin material, or the like. It is envisaged that for best results the shank 20a of the fastener 20 will directly engage the loops 16, but this need not always be the case and a small quantity of the composite material of the respective panel may be located therebetween (as shown in the drawings). The loops 16 may be laid onto the surfaces of the panels 12, 14, or could be incorporated in such a manner as to extend through all or a large proportion of the thickness of the panels 12, 14 if desired.

Rather than have the full end parts of the panels 12, 14 overlap and overlie one another, one or other, or both of the panels 12, 14 may be provided with projecting fingers into which the loops 16 extend, the fingers overlying the other panel (or fingers associated therewith) to form the connection between the panels. Depending upon how this is achieved, the connection between the panels 12, 14 may be designed in such a manner as to resist bending of the assembly.

The use of fasteners 20 in the form of rivets is advantageous in that access is only required to one face of the assembly. However, other forms of radially expandable fastener could be used.

By way of example, nuts and bolts provided with radially expandable components located upon the shanks thereof could be used, if desired. However, tightening of such arrangements may require access to both opposing sides of the assembly.

S The interconnected panels 12, 14 may be used in a wide range of applications. By way of example, they could be used in the formation of the bodywork of road vehicles, aircraft or railway vehicles, or could be used in a number of other applications. The panels may each be of flat, planar form, but this need not be the case and they could be curved or otherwise shaped to suit the application in which they are to be used.

These represent just some modifications and alterations that may be made, and the invention is not restricted in this regard but rather covers all arrangements falling within the scope of the appended claims.

Claims

CLAIMS: 1. A composite material panel arrangement comprising a first composite material panel including a plurality of loops of a reinforcing fibre, a second composite material panel including a plurality of loops of a reinforcing fibre, the first panel being formed with a first opening at least partly surrounded by at least one of the said loops, the second panel being formed with a second opening at least partly surrounded by at least one of the said loops, the first and second openings being aligned with one another, and a fastener member extending through the first and second openings, the fastener being encircled by the reinforcing fibre material forming the loops of the first and second panels.
2. An arrangement according to Claim 1, wherein the fastener is of a type that when fastened is of increased diameter relative to the diameter prior to fastening.
3. A composite material panel arrangement comprising a first composite material panel including a plurality of loops of a reinforcing fibre, a second composite material panel including a plurality of loops of a reinforcing fibre, the first panel being formed with a first opening at least partly surrounded by at least one of the said loops, the second panel being formed with a second opening at least partly surrounded by at least one of the said loops, the first and second openings being aligned with one another, and a fastener member extending through the first and second openings, the fastener being of a type that when fastened is of increased diameter relative to the diameter prior to fastening.
4. An arrangement according to any of the preceding claims, wherein the first panel includes a plurality of first openings, each being at least partly surrounded by at least one of the said loops, and each being aligned with a respective second opening of the second panel.
5. An arrangement according to Claim 4, wherein the first openings are arranged in a line, with the second openings similarly being arranged in a line.
6. An arrangement according to any of the preceding claims, wherein the fastener takes the form of rivet.
7. An arrangement according to any of the preceding claims, wherein the first and/or second panel comprises a sheet of a plastics material in or on which are provided the loops of a reinforcing fibre.
8. An arrangement according to any of the preceding claims, wherein the reinforcing fibre is carbon fibre.
9. An arrangement according to any of the preceding claims, wherein the plastics material of the panel comprises a glass fibre reinforced plastics materials.
10. An arrangement according to any of the preceding claims, wherein the loops are laid onto a surface of the respective panel prior to curing of the material of the panel.
11. An arrangement according to any of the preceding claims, wherein the panels are designed in such a manner as to define abutment features for engagement with the other of the panels, restricting relative movement between the panels, the prestressing or tensioning resulting in an end of one of the panels firmly abutting the abutment feature of the other of the panels.