SE2350569A1 - Laminate material - Google Patents

Abstract

There is provided a laminate material comprising: a first layer comprising one or more protrusions, wherein the first layer is made of a first material; and a second layer comprising a respective one or more through-holes, wherein the second layer is made of a second material different to the first material; wherein the second layer is attached to the first layer such that the protrusions of the first layer respectively extend through the through-holes of the second layer; characterised in that: a size and shape of the protrusions allow withdrawal of the protrusions from the throughholes, and an adhesive is provided between the first and second layer to prevent the withdrawal of the protrusions from the through-holes.

Description

TECHNICAL FIELD The present invention relates to a laminate material, and more particularly to a laminate material comprising two layers of different materials, and a method of pro- ducing the same.

BACKGROUND Laminate materials have been widely used in various applications such as build- ing and construction, transportation, packaging, and furniture. A laminate material is typically composed of two or more layers of different materials that are bonded to- gether to form a single sheet.

Laminate materials can be made using different techniques. Many known tech- niques involve the use of separate fasteners, or the modification or deformation of the materials in the laminate material, thus influencing the resulting properties of the laminate material.

Known laminate materials are also often difficult to manufacture, thus costly to produce. Furthermore, certain materials used in laminate materials may be difficult to process using known manufacturing techniques for laminate materials. This can impact the cost and feasibility of the final product.

Therefore, there is a need for new laminate materials and methods of making them that can overcome these challenges and provide improved properties and cost-effectiveness.

SUMMARY The invention is defined by the appended independent claims. Additional features and advantages of the concepts disclosed herein are set forth in the description which follows, and in part will be clear from the description, or may be learned by practice of the described technologies. The features and advantages of the concepts may be realized and obtained by means of the instruments and combinations partic- ularly pointed out in the appended claims. These and other features of the described technologies will become more fully apparent from the following description and ap- pended claims, or may be learned by the practice of the disclosed concepts as set forth herein.

According to a first aspect, there is provided a laminate material comprising: a first layer comprising one or more protrusions, wherein the first layer is made of a first material; and a second layer comprising a respective one or more through- holes, wherein the second layer is made of a second material different to the first material; wherein the second layer is attached to the first layer such that the protru- sions of the first layer respectively extend through the through-holes of the second layer; characterised in that: a size and shape of the protrusions allow withdrawal of the protrusions from the through-holes, and an adhesive is provided between the first and second layer to prevent the withdrawal of the protrusions from the through- holes.

Advantages of the laminate material includes providing a material with a combina- tion of two desirable sets of material properties (e.g. bulk properties and/or surface properties) and providing a laminate material that does not require separate fasten- ers or deformation of the material so as to maintain an integrity of the material. For example, the laminate material allows, in a single section of laminate material, areas with two different sets of surface properties.

Preferably, a density of the first material is lower than a density of the second ma- terial. An advantage of the density of the first material being lower than a density of the second material is that the laminate material has a reduced weight.

Preferably, a surface of the protrusions is flush with a surface of the second layer opposite to the first layer. ln other words, the protrusions have a height that is sub- stantially identical to a thickness of the second material. Thus, a laminate material with an even surface is obtained.

The first material may comprise organic fibres. Preferably, the first material com- prises wood and/or carbon fibre reinforced plastic. The second material may com- prise a metal. Preferably, the second material comprises or is steel, and optionally stainless steel. The first material comprising a metal, and in particular steel, is partic- ularly advantageous with the second material being carbon fibre reinforced plastic, wood, or concrete.

Preferably, the protrusions are integral to the first layer. An advantage of integral protrusions is to provide a laminate material with high sheer strength.

According to a second aspect, there is proved a method of manufacturing a lami- nate material, the method comprising: providing a first layer comprising one or more protrusions; providing a second layer comprising a respective one or more through- holes, the one or more through-holes having a size and shape allowing the protru- sions to be inserted into, and withdrawn from, the respective through-holes; and at- taching the second layer to the first layer by inserting the protrusions of the first layer into the respective through-holes of the second layer such that the protrusions respectively extend through the through-holes, wherein the step of attaching com- prises providing an adhesive be-tween the first layer and the second layer such that the second layer is held in place on the first layer by the adhesive.

Preferably, the protrusions and/or through-holes substantially maintain their shape and/or size during the manufacturing of the laminate material. For example, the protrusions and/or through-holes substantially maintain their cross-sectional shape and/or cross-sectional size during the manufacturing of the laminate material. Hence, a laminate material is provided which does not require deformation of the protrusions and/or through-holes, so as to maintain an integrity of the material.

Preferably, a size, shape and/or location of at least one of the through-holes is de- termined in dependence on a topology optimization. For example, the topology opti- mization may be performed based on estimated or measured local stress in the lami- nate material. An advantage of the topology optimization is that weight of the lami- nate material may be reduced.

Preferably, the step of providing the first layer and/or the second layer comprises forming the first layer by 3D printing, and wherein, optionally, the first layer has a bent shape. An advantage of forming the first and/or second layer by 3D printing is that it is a cost-effective manufacturing method, which allows a great flexibility with regard to the shape, size and/or location of the protrusions and/or through-holes.

BRIEF DESCRIPTION OF THE DRAWINGS ln order to best describe the manner in which the above-described embodiments are implemented, as well as define other advantages and features of the disclosure, a more particular description is provided below and is illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the invention and are not therefore to be considered to be limiting in scope, the ex- amples will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: Fig. 1a shows an exploded view of a laminate material according to embodi- ments; Fig. 1b shows a laminate material according to embodiments; Fig. 1c shows a cross-section view of a laminate material according to embodi- ments; Fig. 2 shows a method of manufacturing a laminate material according to em- bodiments; Fig. 3a shows a laminate material according to embodiments; Fig. 3b shows a cross-section view of a laminate material according to embodi- ments; Fig. 4 shows a laminate material according to embodiments; Fig. 5 shows a laminate material according to embodiments; Fig. 6 shows a laminate material according to embodiments; Fig. 7a shows a laminate material according to embodiments; Fig. 7b shows estimated local stresses of a laminate material according to em- bodiments; Fig. 8 shows a method of determining a layout, shape and/or size of through- holes in a laminate material according to embodiments; and Fig. 9 shows a car panel made from a laminate material according to embodi- ments. Further, in the figures like reference characters designate like or corresponding ele- ments or parts throughout the several figures. The first digit in the reference charac- ter denotes the first figure in which the corresponding element or part appears.

DETAILED DESCRIPTION Various embodiments of the disclosed methods and arrangements are discussed in detail below. While specific implementations are discussed, it should be under- stood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components, configurations, and steps may be used without parting from the spirit and scope of the claimed invention.

Hereinafter, certain embodiments will be described more fully with reference to the accompanying drawings. lt will be apparent to those skilled in the art that various modifications and variations can be made without departing from the inventive con- cept. Other embodiments will be apparent to those skilled in the art from considera- tion of the specification and practice disclosed herein. lt is to be understood that ele- ments and materials may be substituted for those illustrated and described herein, parts and processes may be reversed or omitted, certain features may be utilized in- dependently, and embodiments or features of embodiments may be combined, all as would be apparent to the skilled person in the art.

The embodiments herein are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive con- cept, and that the claims be construed as encompassing all modifications, equiva- lents and alternatives of the present inventive concept which are apparent to those skilled in the art to which the inventive concept pertains. lf nothing else is stated, dif- ferent embodiments may be combined with each other.

Figs. 1a to 1c show a laminate material 100 according to embodiments. The lami- nate material 100 may also be referred to as a composite material.

Fig. 1a shows the laminate material 100 before assembly. Fig. 1b shows the lami- nate material 100 after assembly. Fig. 1c shows a cross-section A-A of the laminate material 100 after assembly.

Although Fig. 1 shows a laminate material 100 in the shape of a rectangular plate, it will be understood that the laminate material 100 may have any suitable size and/or shape.

The laminate material 100 is a material comprising a plurality of layers including a first layer 101 and a second layer 102. The layers may also be referred to as sheets, laminates, and/or plates. At least two of the layers of the laminate material 100 are preferably made of different materials, e.g. a first layer 101 of a first material and a second layer 102 of a second material. By combining at least two different materials in a laminate material 100, properties of the at least two materials may be combined. lt is accordingly possible to take advantage of desired properties of each respective material. This leads to a greater design flexibility as well as a laminate material 100 with superior performance compared to each of the respective materials.

The laminate material 100 according to embodiments comprises at least two lay- ers. A first layer 101 of the laminate material 100 comprises at least one protrusion 103. The first layer 101 may be referred to as a protrusion layer 101. Preferably, the protrusion layer 101 comprises a plurality of protrusions 103. The protrusions 103 may also be referred to as pins, projections, and/or extensions. The protrusions 103 may be any suitable structure protruding from a surface of the protrusion layer 101. The protrusions 103 may be integral to the protrusion layer 101. Alternatively, the protrusions 103 may be attached onto the protrusion layer 101.

A second layer 102 of the laminate material 100 comprises at least one through- hole 104. The second layer 102 may be referred to as a through-hole layer 102. Preferably, the through-hole layer 102 comprises a plurality of through-holes 104. The through-holes 104 may also be referred to as holes, apertures, slits, slots, and/or openings.

The number of through-holes 104 of the through-hole layer 102 is preferably at least as large as the number of protrusions 103 on the protrusion layer 101. More preferably, the number of protrusions 103 on the protrusion layer 101 is the same as the number of through-holes 104 in the through-hole layer 102. ln the laminate material 100, the through-hole layer 102 is superimposed on the protrusion layer 101 such that the protrusions 103 on the protrusion layer 101 are received by the respective through-holes 104 in the through-hole layer 102. ln other words, in the assembled state, the protrusions 103 extend, at least partly, through the through-holes 104. The protrusions 103 thus engage with the through-holes 104 so as to restrict lateral (in-plane) relative movement of the two layers.

The protrusions 103 have a size and shape that allow them to be inserted into the through-holes 104 and withdrawn from the through-holes 104. lmportantly, the inser- tion and withdrawal of the protrusions 103 may be done without deformation of the protrusions 103 and/or the through-holes 104. ln other words, the protrusions 103 and/or through-holes 104 maintain their shape (e.g. during assembly or manufactur- ing of the laminate material 100). For example, the size and shape of each protrusion 103 may be similar to the size and shape of each respective through-hole 104, so as to allow the protrusion 103 to fit snugly into the through-holes 104, as can be seen in Fig. 1c. ln other words, each protrusion 103 may be conformal to each respective through-hole 104. Optionally, a filler material may be provided to fill any empty space between the protrusions 103 and an edge of the through-holes 104.

The laminate material 100 may further comprise an adhesive provided between the protrusion layer 101 and the through-hole layer 102. Thus, the two layers can be joined and/or attached together. The adhesive may thus prevent the layers of the laminate material 100 from separating. Similarly, the adhesive may also prevent with- drawal of the protrusions 103 from the through-holes 104.

Hence, the laminate material 100 according to embodiments does not require any separate fasteners orjoints. The weight and complexity, as well as the manufactur- ing complexity and cost, of the laminate material 100 is accordingly reduced.

Fig. 2 shows a method of manufacturing a laminate material 100 according to em- bodiments. ln step 201, there is provided a first layer 101 comprising one or more protru- sions 103. ln other words, a protrusion layer 101 is provided. The protrusion layer 101 may be formed by 3D printing. 3D printing is advantageous in that the protru- sion layer 101 may be formed as a bent or curved layer, i.e. a layer with curvature.

Alternatively, the protrusion layer 101 may be formed by attaching at least one protrusion 101 onto a substantially flat layer. Yet as another alternative, protrusions 101 may be formed in the protrusion layer by etching, or otherwise removing mate- rial from a substantially flat layer, so as to form the protrusions 101. lt will be appreci- ated that embodiments are not limited to these methods of providing the protrusion layer 101, and includes any suitable method of providing a protrusion layer 101. ln step 203, there is provided a second layer 102 comprising one or more through-holes 104. ln other words, a through-hole layer 102 is provided. The through-hole layer 102 may be formed by removing portions of a substantially flat layer so as to form through-holes 104. The through-holes 104 may, for example, be formed by laser cutting. However, it will be appreciated that embodiments are not limited to this method of providing the through-hole layer 102, and includes any suit- able method of providing a through-hole layer 102.

The protrusions 103 and the through-holes 104 are provided at corresponding lo- cations on the protrusion layer 101 and the through-hole layer 102, such that when the through-hole layer 102 is superimposed on the protrusion layer 101, the through-holes 104 and the protrusions 103 overlap.

The protrusions 103 and the through-holes 104 have a corresponding size and shape allowing the protrusions 103 to be inserted into, and withdrawn from, the re- spective through-holes 104. ln step 205, an adhesive is applied to a contacting surface between the protrusion layer 101 and the through-hole layer 102. That is, the adhesive may be provided on a surface of the protrusion layer 101 facing the through-hole layer 102 (i.e. the surface comprising the protrusions 103) or alternatively on a surface of the through- hole layer 102 facing the protrusion layer 101. ln step 207, the through-hole layer 102 is attached to the protrusion layer 101 by inserting the protrusions 103 into the through-holes 104. Thus in the assembled state, the protrusions 103 extend, at least partially, through the through-holes 104, and the adhesive joins the two layers securely together. lmportantly, the protrusions 103 and through-holes 104 are shapes such that they maintain their shape when the protrusions 103 are inserted into the through-holes 104. ln other words, the protru- sions 103 are not substantially deformed during the insertion step. Thus, the shape and size of the protrusions 103 allow them to, in the absence of the adhesive mate- rial, be withdrawn from the through-holes 104. Furthermore, the two layers are held in place by the adhesive, and not by any deformation of the protrusions 103 and/or through-holes 104. ln embodiments, a height of the protrusions 103 may be larger than the thickness of the through-hole layer 102 such that the protrusions 103 protrude out of the through-hole layer 102 after assembly of the laminate material 100. ln such a case, the height of the protrusions 103 may be adjusted after assembly (e.g. by cutting of a top portion of the protrusions 103) such that an even surface can be obtained. However, in embodiments, any such adjustment of the height of the protrusions 103 does not deform the protrusions 103 and/or through-holes 104 in a way which pre- vents withdrawal of the protrusions 103 from the through-holes 104. ln other words, only the height of the protrusions 103 is adjusted, while the cross-sectional shape and size is maintained.

Furthermore, the assembly of the laminate material 100 does not involve any de- formation of material, either via insertion of fasteners (e.g. by creation of a hole or notch), or by deformation of the protrusions 103 and/or through-holes 104. Thus, the integrity of the materials in the laminate material 100 will be maintained during as- sembly, reducing the risk of subsequent failure of the material, e.g. by catastrophic failure through formation of cracks, failure by fatigue, or the like.

The laminate material 100 according to embodiments may be made from any suitable combination of materials. The protrusion layer 101 may be made of a first material and the through-hole layer 102 may be made of a second material.

A density of the first material (i.e. the protrusion layer 101) may be lower than a density of the second material (i.e. the through-hole layer 102). The weight of the laminate material 100 may thus be reduced compared to a laminate material 100 comprising two solid layers (i.e. layers not comprising protrusions 103 and through- holes 104).

The through-hole layer 102 may be made of a first material comprising a metal or metal alloy. For example, the first material may comprise aluminum, chromium, cop- per, gold, iron, lead, magnesium, mercury, nickel, platinum, silver, steel, tin, titanium, tungsten, zinc, cobalt, palladium, bronze, brass, steel, stainless steel, or a combina- tion thereof. Preferably, the through-hole layer 102 is made of a material comprising stainless steel.

Although the through-hole layer 102 has been described in relation to metals and/or metal alloys, it will be appreciated that the through-hole layer 102 in embodi- ments may be made from any suitable material. The choice of specific material for the through-hole layer 102 may be made in dependence on desired material charac- teristics for a certain application Which is Well Within the capabilities of the skilled person.

A through-hole layer 102 comprising metal is particularly advantageous When the through-hole layer 102 acts as a surface layer. A through-hole layer 102 comprising metal ensures, among others, that the laminate material 100 has a high tolerance surface, is substantially fire resistant, and/or heat resistant. Furthermore, a through- hole layer 102 comprising metal has a high tensile strength.

The protrusion layer 101 may be made of non-metals, polymers, wood, concrete, ceramics, composites, rubber, plastics, adhesives (e.g. epoxy), or a combination thereof. Preferably, the protrusion layer 101 is made from a material comprising or- ganic fibres. Additionally, or alternatively, the protrusion layer 101 may be made from a composite comprising a matrix filler material and organic fibres. Preferably, the protrusion layer 101 is made from carbon fibre reinforced plastic or wood.

The laminate material 100 according to embodiments is particularly suitable for use with a protrusion layer 101 comprising a material with organic fibres, such as CFRP, and/or wood. These materials are particularly sensitive to notches which sever the load bearing fibres, thus resulting in the performance of the material being degraded and additional stress concentrations being introduced. However, as the laminate material 100 according to embodiments requires no separate fasteners and/or any deformation of the protrusion layer 101, the integrity of the organic fibre- containing material can be maintained.

The range of materials for the protrusion layer 101 offers a great design variety dependent on the specific characteristics that are required for a certain application. For example, materials comprising organic fibres (e.g. wood, CFRP) have a high stiff- ness, low weight, and resistance to corrosion, among others. As another example, a plastic material or a polymer material offers a very low weight and low-cost manufac- turing. Furthermore, a protrusion layer 101 made of concrete or the like, offers a great compression strength, while a lack of tensile strength may be compensated by a through-hole layer 102 made of metal (in a similar way to reinforced concrete).

Although the protrusion layer 101 has been described in relation to the above range of materials, it will be appreciated that the protrusion layer 101 in embodi- ments may be made from any suitable material. The choice of specific material for the protrusion layer 101 may be made in dependence on desired material characteristics for a certain application Which is Well Within the capabilities of the skilled person.

Preferably, the laminate material 100 may comprise a through-hole layer 102 made of metal and a protrusion layer 101 made of carbon fibre reinforced plastic. More preferably, the laminate material 100 comprises a through-hole layer 102 made of steel (such as stainless steel) and a protrusion layer 101 made of carbon fi- bre reinforced plastic.

Another preferred option is a laminate material 100 comprising a through-hole layer 102 made of metal and a protrusion layer 101 made of wood. More preferably, the laminate material 100 comprises a through-hole layer 102 made of steel (such as stainless steel) and a protrusion layer 101 made of wood.

The laminate material 100 allows different surface properties in different areas of the laminate material 100. That is, a first set of properties may be provided by the through-hole layer 102 while a second set of properties may be provided by the pro- trusion layer 101. Thus, at the surface of the through-hole layer 102 (facing away from the protrusion layer 101), there are both areas With the first set of properties and areas with the second set of properties (i.e. areas corresponding to the through- holes 104 and protrusions 103). The set of properties may include hardness (i.e. re- sistance to indentation or scratching), roughness, directional strength (i.e. the mate- rial being stronger in a specific direction, for example due to fibre alignment), poros- ity, adhesion (i.e. the ability of the surface to stick to another material), corrosion re- sistance, friction coefficient (i.e. resistance to sliding or movement of the surface against another material), optical properties (including transparency, reflectivity, re- fraction coefficient, and/or color), electrical properties (including electrical conduc- tivity and/or electrical resistance), thermal properties (including thermal conductivity, emissivity, and/or reflectivity), or a combination thereof.

Hence, the laminate material 100 offers, in a single element, a wide design flexi- bility, where the surface properties of the material can be tailored in different areas of the laminate material 100. The size, shape and/or locations of the protrusions 103 and through-holes 104 may accordingly be determined in dependence on where on the surface the different sets of properties are desirable for a specific application.

For example, the protrusion layer 101 may be at least partly transparent, e.g. the protrusion layer 101 may be made from a transparent plastic. A laminate material 100 with a transparent protrusion layer 101 is particularly suitable for applications Where both a transparent portion and a non-transparent portion is required or de- sired. For these applications, a single section of the laminate material 100 according to embodiments may provide both of these portions. For example, a car panel may be made from the laminate material 100 where a transparent light cover (for e.g. the taillights, the headlights, the indicators and/or blinkers) may be integrated into the panel itself. Thus a single piece of laminate material 100 may provide both a metal panel and an integrated transparent cover for the headlights/taillights/indicators.

The laminate material 100 may furthermore comprise one or more additional lay- ers. The additional layers may include an insulating layer and/or an electrically con- ductive layer. Alternatively, the through-hole layer 102 and/or the protrusion layer 101 may be made of an electrically conductive material and/or an insulating material, thus ensuring that the laminate material 100 is electrically conductive or insulating respectively.

Fig. 3 shows an embodiment with a laminate material 100 comprising three lay- ers. Fig. 3a shows a perspective view of the laminate material 100. Fig. 3b shows a cross-section B-B of the laminate material 100.

The laminate material 100 comprises one protrusion layer 101 comprising at least one protrusion 103 on each of two opposing surfaces, and two through-hole layers 102a, 102b each comprising a respective at least one through-hole 104. That is, the protrusion layer 101 is sandwiched between the two through-hole layers 102a, 102b.

Although the through-holes 104 are shown in the same locations on both through-hole layers 102a, 102b, it will be appreciated that embodiments include lam- inate materials 100 where the through-holes 104 are located in different locations on the two through-hole layers 102a, 102b.

Figs. 4 to 6 show laminate materials 100 with different layouts of protrusions 103 and through-holes 104. As the examples in Figs. 4 to 6 show, the protrusions 103 may have various different shapes. ln particular, the protrusions 103 may have any shape allowing the protrusions 103 to be inserted into and withdrawn from the through-holes 104.

All protrusions 103 may have the same or similar shape and/or size. Alternatively, the protrusions 103 may have different shapes and/or sizes.

The protrusions 103 may have any cross-sectional shape, including but not lim- ited to diamond-shaped, circular, oval, rectangular, quadratic, hexagonal, and/or po- lygonal. The protrusions 103 may, additionally or alternatively, have an irregular cross-sectional shape.

The protrusions 103 may have a cross-sectional area that is constant or decreas- ing with the height of the protrusions 103, the height being defined as the perpendic- ular distance from the surrounding surface of the protrusion layer 101. These protru- sion shapes allow the protrusions 103 to be inserted into the through-holes 104 and withdrawn from the through-holes 104.

Examples of protrusion shapes with constant cross-sectional area include, but are not limited to, cylindrical protrusions, cubical or cuboidal protrusions, prism-shaped protrusions, or the like.

Alternatively, the protrusions 103 may have a tapered, staggered, or othen/vise decreasing cross-section. That is, a shape where the cross-sectional area decreases 11 with the height of the protrusions 103. ln other words, the cross-sectional area is smaller at a portion of the protrusion 103 away from the surrounding surface, than at a portion near the surrounding surface of the protrusion layer 101. The protrusions 103 may have any tapered shape, including but not limited to pyramidal, conical, hemispherical, hemi-ellipsoidal, polyhedron-shaped, and/or tetrahedron-shaped. The protrusions 103 may be provided with a flat top portion or surface, e.g. by cutting off the top portion of the above-mentioned shapes, so as to obtain a cut-off pyramid, a cut-off cone, a cut-off hemisphere, a cut-off hemi-ellipsoidal, a cut-off polyhedron- shape, and/or a cut-off tetrahedron-shape. An even surface can accordingly be ob- tained when the protrusions 103 extend through the through-holes 104 in the as- sembled laminate material 100.

The protrusions 103 may have a dimension that is greater than its height. The di- mension may be a diameter, a width, or a length. ln other words, the protrusions 103 may have a width, length, or diameter that exceeds its height. For example, the pro- trusions 103 may have a dimension of at least 5 mm, preferably at least 10 mm, more preferably at least 20 mm, and yet more preferably at least 30 mm. Protrusions 103 of this size can withstand significant shear stresses that the laminate material 100 may be subject to. Thus, the protrusions 103, can enhance the shear strength of the adhesive. The laminate material 100 according to embodiments is thus particu- larly advantageous in applications where the material is subject to large shear stresses.

The height of the protrusions 103 may be similar, or substantially identical, to the thickness of the through-hole layer 102. This height ensures that the top surface of the protrusions 103 is flush or even with the surface of the through-hole layer 102, when the laminate material 100 is assembled. Thus, a smooth and/or even surface may be achieved.

As shown in Figs. 4 to 6, the protrusions 103 and through-holes 104 may be posi- tioned in a regular and/or symmetric manner. The protrusions 103 may be arranged in rows and/or columns. For example, the protrusions 103 may be arranged in one or more rows with a plurality of protrusions 103 in each row. Additionally, or alterna- tively, the protrusions 103 may be arranged in one or more columns with a plurality of protrusions 103 in each column. A row may be perpendicular to a column. For ex- ample, the protrusions 103 may be arranged in a grid pattern. Alternatively, a row may be angled compared to a column by any suitable angle, for example 30, 45, or 60 degrees. ln other words, rows and/or columns may be shifted compared to adja- cent rows and/or columns respectively. For example, the protrusions 103 may be ar- ranged in a grid pattern that is shifted, slanted, or skew. Protrusions 103 in a row and/or column may be regularly spaced, or alternatively, the distance between pro- trusions 103 may vary. 12 Fig. 7 shows a laminate material 100 in which the protrusions 103 and through- holes 104 have alternatively been arranged irregularly. Fig. 7a shows the laminate material 100 in a perspective view. Fig. 7b shows a cross-section C-C of the lami- nate material 100 together with a local stress curve along the cross-section C-C.

The layout, size, and/or shape of the protrusions 103 and through-holes 104 may be determined in dependence on a topology optimization. For example, through- holes 104 may be positioned, sized, and/or shaped in dependence on measured and/or estimated local stresses in the material, as can be seen in Fig. 7b. lt will be appreciated that the stress curve shown in Fig. 7b is an exemplary stress curve and will be dependent on the application and materials used.

For example, if the laminate material 100 is used in an application where the local stress is expected to be low at certain locations, through-holes 104 may be provided at these locations. Thus, material of the through-hole layer 102 may be removed (i.e. by providing the through-holes 104) in locations with low local stress, so as to re- duce the weight of the through-hole layer 102 and in turn the laminate material 100. This is particularly advantageous when the material of the through-hole layer 102 has a higher density than the material of the protrusion layer 101.

For example, through-holes 104 may be provided in locations where the local stress is below a threshold stress amount 701. The threshold stress amount 701 may be determined in dependence on the strength of the protrusion layer 101, e.g. based on the stress level that the protrusion layer 101 can handle without any contribution by the through-hole layer 102. The size and/or shape of the through-holes 104 may also be determined in dependence on where the local stress is below a threshold stress amount 701.

Although the size, shape and layout of the protrusions 103 have been discussed above in relation to Figs. 4 to 7, it will be appreciated that corresponding considera- tions apply to the through-holes 104.

Fig. 8 shows a method of manufacturing a laminate material 100 in dependence on local stress levels. ln step 801, the local stress levels for a certain application or use are estimated and/or measured. For example, the local stress in the material may be estimated us- ing a finite element analysis or other suitable method. As another example, the local stress in the material may be measured using a reference material (e.g. without pro- trusions 103 and/or through-holes 104) and one or more strain gauges. ln step 803, one or more through-holes 104 are provided in a through-hole layer 102 in dependence on the local stress levels. The location, size and/or shape of the through-holes 104 may be determined in dependence on the local stress levels. For example, the location, size and/or shape of the through-holes 104 may be deter- mined in dependence on the local stress level being below a threshold amount. 13 ln step 805, there is provided a protrusion layer 101 comprising a respective one or more protrusions 103 corresponding to the created through-holes 104. ln step 807, the laminate material 100 is manufactured using the through-hole layer 102 and the protrusion layer 101. The laminate material 100 may be manufac- tured in accordance with the method of Fig. 2.

The laminate material 100 according to embodiments may be used in many dif- ferent industries, including but not limited to motor vehicles, airplanes, ships, railway carriages, railway locomotives, buildings or other (e.g. civil) structures, and/or furni- ture. The laminate material 100 is particularly advantageous in applications that ex- hibit large shear stresses while requiring a material of low weight.

For example, panels for motor vehicles may be made from the laminate material 100 as can be seen in Fig. 9 which shows a car panel made from the laminate mate- rial 100 according to embodiments. ln the car panel of Fig. 9, the laminate material 100 is made from a through-hole layer 102 comprising metal and a protrusion layer 101 comprising CFRP. The size, shape and/or location of the through-holes 104 have been determined in dependence on a topology optimization. Hence a laminate material 100 is provided that offers a low weight and high strength, which is advanta- geous for use of the car panel in a motor vehicle.

Throughout this specification, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than in the mandatory sense (i.e. meaning must).

Throughout this specification, the words "comprise", "include", and variations of the words, such as "comprising" and "comprises", "including", "includes", do not exclude other elements or steps.

As used throughout this specification, the singular forms "a", "an", and "the", in- clude plural referents unless explicitly indicated othen/vise. Thus, for example, refer- ence to "an" element includes a combination of two or more elements, notwithstand- ing use of other terms and phrases for one or more elements, such as "one or more" or "at least one".

The term "or" is, unless indicated othen/vise, non-exclusive, i.e. encompassing both "and" and "or". For example, the feature "A or B" includes feature feature "B" and feature "A and B".

Unless othen/vise indicated, statements that one value or action is "based on" and/or "in dependence on" another condition or value or action, encompass both in- stances in which the condition or value or action is the sole factor and instances where the condition or value or action is one factor among a plurality of factors.

Unless othen/vise indicated, statements that "each" instance of some collection have some property should not be read to exclude cases where some otherwise identical or similar members of a larger collection do not have the property, i.e. each does not necessarily mean each and every.

Claims (1)

1. A laminate material comprising: a first layer comprising one or more protrusions, wherein the first layer is made of a first material; and a second layer comprising a respective one or more through- holes, wherein the second layer is made of a second material different to the first material; wherein the second layer is attached to the first layer such that the protrusions of the first layer respectively extend through the through- holes of the second layer; characterised in that: a size and shape of the protrusions allow withdrawal of the protrusions from the through-holes, and an adhesive is provided between the first and second layer to prevent the withdrawal of the protrusions from the through-holes. The laminate material according to claim 1, wherein a density of the first material is lower than a density of the second material. The laminate material according to claim 1 or 2, wherein a surface of the protrusions is flush with a surface of the second layer opposite to the first layen The laminate material according to any preceding claim, wherein the first material comprises organic fibres. The laminate material according to any preceding claim, wherein the first material comprises wood and/or carbon fibre reinforced plastic. The laminate material according to any preceding claim, wherein the first material is at least partially transparent. The laminate material according to any preceding claim, wherein the second material comprises a metal. The laminate material according to any preceding claim, wherein the second material is steel, and optionally stainless steel. The laminate material according to any preceding claim, wherein the protrusions are integral to the first layer. A method of manufacturing a laminate material, the method comprising: providing a first layer comprising one or more protrusions; providing a second layer comprising a respective one or more through-holes, the one or more through-holes having a size and shape allowing the protrusions to be inserted into, and withdrawn from, the re- spective through-holes; and attaching the second layer to the first layer by inserting the protru- sions of the first layer into the respective through-holes of the second layer such that the protrusions respectively extend through the through- holes, wherein the step of attaching comprises providing an adhesive be- tween the first layer and the second layer such that the second layer is held in place on the first layer by the adhesive. The method according to claim 10, wherein the protrusions and/or through-holes substantially maintain their shape and/or size during the manufacturing of the laminate material. The method according to claim 10 or 11, wherein the protrusions and/or through-holes substantially maintain their cross-sectional shape and/or cross-sectional size during the manufacturing of the laminate material. The method according to any of claims 10 to 12, wherein a size, shape and/or location of at least one of the through-holes is determined in de- pendence on a topology optimization. The method according to any of claims 10 or 13, wherein the step of providing the first layer comprises forming the first layer by 3D printing, and wherein, optionally, the first layer has a bent shape.