Curved aluminum foam sandwich with delamination insert

Abstract

Curved aluminum foam sandwich (200), comprising: an inner sheet (202); an outer sheet (204) with a through hole (214); a core (206) between the inner sheet (202) and the outer sheet (204); and a delamination insert (302) at a bending point (210) between the inner sheet (202) and the outer sheet (204), such that side walls of the delamination insert (302) are in direct contact with the core (206) and the inner sheet (202), wherein the delamination insert (302) comprises a tab (502) which is positioned to extend through the through hole (214).

Description

INTRODUCTION

[0001] The present invention relates to manufacturing and construction materials and technologies, and in particular to a curved aluminum foam sandwich with a delamination insert.

[0002] For general background information, reference should be made in advance to the publications EP 1 136 148 A2 and DE 103 50 953 A1.

[0003] An aluminum foam sandwich is a sandwich panel product typically consisting of a porous aluminum foam core sandwiched between two aluminum sheets (commonly referred to as the inner and outer sheets). Recently, manufacturers and materials scientists have begun to utilize aluminum foam sandwiches in a wide variety of applications to take advantage of their numerous beneficial material properties. Aluminum foam sandwiches are suitable for a wide range of applications in automotive engineering (as lightweight frames, shells, beams, etc. in cars, trains, trucks, and aircraft), aerospace, buildings (as structural and design components), and electronics (as substrates, carriers, etc.).

[0004] In particular, aluminum foam sandwich construction is a lightweight structural material with a relatively high stiffness-to-mass ratio and favorable energy absorption compared to steel and other materials. Due to its inherent plastic deformation properties, aluminum foam sandwich construction can absorb relatively high impact energies. Furthermore, aluminum foam sandwich construction surpasses non-metallic foams, such as polystyrene foam, in terms of heat resistance and flammability. Ease of manufacture is also a significant advantage, as aluminum foam sandwich construction can be produced and processed at lower temperatures than steel. BRIEF SUMMARY OF THE INVENTION

[0005] According to the invention, a curved aluminum foam sandwich is presented, characterized by the features of claim 1.

[0006] The aluminum foam sandwich comprises an inner sheet, an outer sheet with a through-hole, and a core sandwiched between the inner and outer sheets. A delamination insert is positioned at a bend between the inner and outer sheets, ensuring that the delamination insert's sidewalls are in direct contact with the core and the inner sheet. The delamination insert includes a flap positioned to extend through the through-hole.

[0007] In addition to one or more of the features described here, the core in some embodiments optionally includes a porous foam core, the inner sheet comprises aluminium and the outer sheet comprises aluminium.

[0008] In some embodiments, a weld seam is optionally created above the through-hole and in direct contact with the tab of the delamination insert.

[0009] In some embodiments, a leading edge of the delamination insert is optionally in direct contact with a surface of the outer sheet. In some embodiments, a trailing edge, opposite the leading edge of the delamination insert, optionally extends beyond a surface of the inner sheet.

[0010] In some embodiments, sections of the inner sheet and sections of the porous foam core are optionally removed to expose the surface of the outer sheet. In some embodiments, these sections of the inner sheet and the sections of the porous foam core are optionally removed at an angle of 45 degrees to the surface of the outer sheet.

[0011] Furthermore, according to the invention, a vehicle is presented which is characterized by the features of claim 8.

[0012] The vehicle comprises a component made of a bent aluminum foam sandwich. The bent aluminum foam sandwich includes an inner sheet, an outer sheet with a through-hole, and a core between the inner and outer sheets. A delamination insert is positioned at a bend between the inner and outer sheets, so that the side walls of the delamination insert are in direct contact with the core and the inner sheet. The delamination insert includes a tab positioned to extend through the through-hole.

[0013] Furthermore, a method for manufacturing a bent aluminum foam sandwich is described, comprising the provision of an inner sheet, an outer sheet with a through-hole, and a core between the inner and outer sheets. The method includes positioning a delamination insert at a bending point between the inner and outer sheets such that the sidewalls of the delamination insert are in direct contact with the core and the inner sheet. The delamination insert includes a tab positioned to extend through the through-hole.

[0014] The aforementioned features and advantages, as well as other features and advantages of the invention, will readily become apparent from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Further features, advantages, and details are listed only as examples in the following detailed description, which refers to the drawings. These show: Fig. 1 a vehicle designed according to one or more embodiments; Fig. 2 a view of an aluminium foam sandwich after forming the inner and outer sheets according to one or more embodiments; Fig. 3 a view of the aluminium foam sandwich after bending according to one or more embodiments; Fig. 4 a cross-sectional view of the aluminium foam sandwich after insertion of a delamination insert according to one or more embodiments; Fig. 5 a front side of the aluminium foam sandwich after bonding the delamination insert to the outer sheet according to one or more embodiments; Fig. 6 a rear view of the aluminium foam sandwich after bonding the delamination insert to the inner sheet according to one or more embodiments; and Fig. 7 a flowchart according to one or more embodiments. DETAILED DESCRIPTION

[0016] The following description is for illustrative purposes only. It is understood that in the drawings, corresponding reference symbols denote identical or equivalent parts and features.

[0017] According to one embodiment, a vehicle is in Fig. 1. Generally referred to as 100. The vehicle 100 is depicted as an automobile with a body 102. The body 102 comprises a passenger compartment 104, in which a steering wheel, front seats, and rear seats (not shown separately) are arranged. The various components within the passenger compartment 104 are for illustrative purposes only. A number of components are arranged in the body 102, including, for example, an electric motor 106 (shown by projection under the hood). The electric motor 106 is shown for illustrative and explanatory purposes only.

[0018] As explained in more detail below, one or more components 108 of the body 102 (as shown, a rear door) can consist of a curved aluminum foam sandwich formed according to one or more embodiments. Component 108 is shown for illustrative and explanatory purposes only. It is understood that each component of the body 102 (and indeed many components of the vehicle 100 in general) can be manufactured wholly or partially by means of a curved aluminum foam sandwich formed according to one or more embodiments. Although the present invention is described primarily in connection with a component 108 of the vehicle 100 for the purpose of illustration and explanation, the aspects described here can also be integrated into any manufacturing and construction application, particularly in vehicle construction (e.g., as a lightweight frame, shell, support, etc.).in cars, trains, trucks and airplanes), in aerospace, in buildings (as structural and design components) and in electronics (e.g. as substrate, carrier, etc.), and all such designs and applications fall within the considered scope of application of this invention.

[0019] As previously discussed, aluminum foam sandwiches are desirable for a range of applications due to their unique properties, such as low weight, high specific stiffness, high specific strength, impact resistance (energy absorption), vibration damping, sound absorption, and electromagnetic shielding. Unfortunately, methods for manufacturing aluminum foam sandwiches are limited to flat, mostly sheet-like applications, as bending an aluminum foam sandwich to create complex geometries leads to the separation of the foam core from the inner and outer sheets. For applications requiring complex geometries, manufacturers typically design their own custom fixtures and blow in their own aluminum foam composition—a complex, costly, and small-scale solution.

[0020] This invention presents a novel type of aluminum foam sandwich and a bending method for it, which makes it possible to bend commercially available flat aluminum foam sandwiches to create complex geometries without delamination. The method begins with a flat aluminum foam sandwich consisting of an inner sheet, an outer sheet, and a porous foam core sandwiched between the inner and outer sheets. The aluminum foam sandwich is cleaned, trimmed, and / or otherwise processed to create an initial flat surface. This cutting / forming process (also referred to as "rough-in") involves both sheets and the foam core. Following the initial rough-in, the inner sheet of the aluminum foam sandwich is, for example, mitered at 45 degrees, and sections of the foam core are removed (scraped, cut, sanded, ground, etc.) to allow the aluminum foam sandwich to be folded.The outer sheet of the aluminum foam sandwich is not cut in this process. In other words, the outer sheet remains a single, continuous piece (even though it was formed during the initial rough-in).

[0021] After the inner sheet is cut to size, one or more holes are opened in the outer sheet at the bend between the inner and outer sheets to facilitate folding. The inner sheet is bent towards the outer sheet, and an insert with one or more tabs is placed in the bend against the outer sheet, so that one end of the tab(s) protrudes through the hole(s). The tabs and holes serve to connect the insert and the outer sheet. The insert can be attached to the bent aluminum foam sandwich by welding or other methods (e.g., adhesives, laser welding, etc.) to the outer and / or inner sheet. In some embodiments, a weld bead is applied to the outer sheet across all exposed tabs.

[0022] After cutting, the inner sheet is bent towards the outer sheet, and an insert with one or more tabs is placed in the bend directly against an inner surface of the outer sheet. The insert can be attached to the bent aluminum foam sandwich by welding or other methods (e.g., with adhesives) to the inner surface of the outer sheet (i.e., without using through holes).

[0023] Components manufactured using bent aluminum foam sandwiches according to one or more embodiments offer several technical advantages over previous solutions. In particular, it has been found that the insert(s) in the bent aluminum foam sandwich significantly improves the overall structural performance of the part after assembly, even when the bent aluminum foam sandwich is bent into complex geometries, and solves the biggest problem in bending an aluminum foam sandwich—namely, the separation of the metal foam from its base material. Furthermore, inserts that connect the inner and outer sheets need not necessarily be limited to the bending point, as they can be placed anywhere within the aluminum foam sandwich (e.g., as crack stoppers, etc.) to further prevent separation and improve the overall structural properties of a bent aluminum foam sandwich.Advantageously, the curved aluminum foam sandwiches described here can be easily integrated into the body structure, chassis, or other components of a vehicle, building, etc., using simple solutions such as mechanical fastenings and welding. The techniques described here make it possible to modify commercially available, flat aluminum foam sandwiches to enable complex geometries to be produced more efficiently and on a larger scale than with current, custom-made solutions.

[0024] Fig. Figure 2 is a view of an exemplary aluminum foam sandwich 200. The aluminum foam sandwich 200 can be a structural and / or design element of an electric vehicle (e.g., one or more components 108 of the body 102 of the vehicle 100). In some embodiments, the component 108 of the body 102 of the vehicle 100 (see Figure 2) is Fig. 1) manufactured wholly or partially by bending, forming, welding and other processing of a raw (flat, planar) aluminum foam sandwich not shown separately, as further described below.

[0025] As in Fig. As shown in Figure 2, the aluminum foam sandwich 200 comprises an inner sheet 202, an outer sheet 204, and a porous foam core 206 between the inner sheet 202 and the outer sheet 204. In some embodiments, the inner sheet 202 and the outer sheet 204 are aluminum sheets, although other materials such as non-aluminum metals (e.g., steel, copper, etc.), non-metals (e.g., ceramics), and / or aluminum alloys are also possible. The inner sheet 202 and the outer sheet 204 can be brought to any desired thickness by processes such as rolling and / or stamping.

[0026] In some embodiments, the porous foam core 206 is optionally a core made of aluminum or an aluminum alloy (e.g., AlCu4, AlSi9Cu3, aluminum-magnesium alloys, etc.). The porous foam core 206 is not intended to be particularly confined, but can, for example, comprise closed-cell and / or open-cell configurations (see Fig. 4) In some embodiments, the porous foam core 206 is optionally produced from a liquid metal and / or by powder metallurgy. In some embodiments, a foamable precursor (not shown separately) is optionally expanded between the inner sheet 202 and the outer sheet 204. The precursor composition may include, for example, Al-Si alloys, Al-Si-Cu alloys, and / or Al-Si-Mg alloys.

[0027] In some embodiments, a chemical bond optionally forms upon contact of the foamable precursor and / or the liquid metal with the surfaces of the inner sheet 202 and the outer sheet 204. In some embodiments, the porous foam core 206 and / or the precursor materials are optionally bonded to the inner sheet 202 and the outer sheet 204 by gluing, brazing, and / or diffusion welding. In some embodiments, the precursor optionally comprises a foamable metal melt that is injected between the inner sheet 202 and the outer sheet 204. The foamable metal melt can be rapidly solidified (e.g., cooled) so that the interior of the metal melt can foam up. In powder metallurgy processes, the metal powders are compacted together with the inner sheet 202 and the outer sheet 204. The resulting sandwich compact composite is heated to transform the core layer into foam.In some embodiments, the melting point of the inner sheet 202 and the outer sheet 204 is optionally above the melting point of the foamable metal powder precursors.

[0028] In some embodiments, the aluminum foam sandwich 200 begins as a raw (flat) aluminum foam sandwich (not shown separately). In some embodiments, the inner sheet 202, the outer sheet 204, and the porous foam core 206 are optionally cut or otherwise processed to assume an initial rough-in form.

[0029] In some embodiments, after the initial rough-in, sections of the inner sheet 202 and the porous foam core 206 are optionally removed at an angle to define one or more sections 208 of the aluminum foam sandwich 200, each separated at a bend 210. Fig. For the sake of simplicity, a single section 208 is shown in Figure 2. The outer sheet 204 is not cut or otherwise removed. In other words, the outer sheet 204 remains as a single, continuous sheet, and the sections 208 thus form a single, continuous part. Sections of the inner sheet 202 and the porous foam core 206 can be removed, for example, by cutting, scraping, sanding, grinding, etc. In some embodiments, sections of the inner sheet 202 and the porous foam core 206 are cut at a 45-degree angle, although, depending on the desired configuration of the aluminum foam sandwich 200 after folding, other cutting techniques with any desired cutting angles (degrees of cut) also fall within the scope of this invention. In other words, the inner sheet 202 and the porous foam core 206 can be installed at any angle (e.g. 5 degrees, 20 degrees, 60 degrees, 80 degrees, etc.).) can be cut to allow any bending configuration that is limited only by the tooling limitations associated with the chosen cutting method.

[0030] In some embodiments, a section 212 of the outer sheet 204 is optionally exposed after sections of the inner sheet 202 and the porous foam core 206 have been removed to define the sections 208. According to the invention, one or more through-holes 214 are formed in the section 212 of the outer sheet 204. The through-holes 214 can be produced by any suitable method, such as cutting through the outer sheet 204. It should be noted that the through-holes 214 will be located in the bend 210 between two sections 208 of the aluminum foam sandwich 200.

[0031] Fig. Figure 3 shows a view of the aluminum foam sandwich 200 after bending the sections 208 according to one or more embodiments. In some embodiments, the sections 208 are optionally bent towards each other along each bend point 210. Fig. Figure 3 merely represents an exemplary configuration of the aluminum foam sandwich 200 after bending the sections 208. It is understood that the aluminum foam sandwich 200 can comprise more or fewer sections 208 with the same or different configurations (shapes) than those shown. By changing the number and shape of the sections 208 and the position of the bending points 210, the final, bent configuration of the aluminum foam sandwich 200 can be modified as required for a specific application.

[0032] According to the invention, one or more delamination inserts 302 are positioned between respective sections 208 of the aluminum foam sandwich 200. The delamination inserts 302 can be made of the same or a different material than the inner sheet 202 and the outer sheet 204. For example, the delamination inserts 302 can be made of aluminum, aluminum alloys, steel, steel alloys, non-metals, and combinations thereof. The delamination inserts 302 can be manufactured in any desired thickness. In some embodiments, the delamination inserts 302 have a thickness that is less than the width of the through-holes 214.

[0033] Each delamination insert 302 is positioned along a bending point 210 between the respective sections 208. According to the invention, a delamination insert 302 comprises one or more extension sections or tabs (see Fig. 5), each configured to extend through one of the through-holes 214. In other words, a delamination insert 302 can be positioned against the outer sheet 204 at a bend (i.e., at a bend point 210) such that one end of a tab protrudes through a corresponding through-hole 214. It has been shown that such positioning of one or more delamination inserts 302 within the aluminum foam sandwich 200 advantageously prevents the porous foam core 206 from separating from the inner sheet 202 and outer sheet 204. Furthermore, the tabs and through-holes 214 serve to connect the delamination insert 302 and the outer sheet 204. In some embodiments, the sections 208 are bent towards each other along each bend point 210 after the delamination insert 302 has been connected to the outer sheet 204.

[0034] Fig. Figure 4 is a cross-sectional view of a section of the aluminum foam sandwich 200 after insertion of the delamination insert 302 according to one or more embodiments. As shown in Fig. As shown in Figure 4, the porous foam core 206 can comprise a metal mesh 402 and a plurality of pores 404. In some embodiments, the metal mesh 402 of the porous foam core 206 is optionally attached to the inner sheet 202 and outer sheet 204. The metal mesh 402 can, for example, consist of a metal material (e.g., aluminum, aluminum alloy, etc.) which is welded and / or directly bonded to the material of the inner sheet 202 and outer sheet 204 under the influence of heat.

[0035] As in Fig. As further shown in Figure 4, in some embodiments, a section 406 of the delamination insert 302 optionally extends beyond the inner sheet 202. The length by which the section 406 extends beyond the inner sheet 202 is not to be specifically limited. The section 406 of the delamination insert 302 can serve as an anchor point for one or more welds (not shown separately) that are made between the delamination insert 302 and the inner sheet 202.

[0036] In some embodiments, the delamination insert 302 optionally comprises a leading edge 408 and a trailing edge 410. In some embodiments, the leading edge 408 is optionally in direct contact with the outer sheet 204. In some embodiments, the trailing edge 410 extends beyond the inner sheet 202 (as in Fig. 4 shown). In some embodiments, the trailing edge 410 is optionally flush with the inner sheet 202 (within manufacturing tolerances, not shown separately). In some embodiments, side walls 412 of the delamination insert 302 are optionally in direct contact with the porous foam core 206 and the inner sheet 202.

[0037] Fig. Figure 5 is a front face of the aluminum foam sandwich 200 after bonding the delamination insert 302 to the outer sheet 204 according to one or more embodiments. According to the invention, the delamination insert 302 comprises a tab 502. As already mentioned, the tab 502 is dimensioned to fit into a through-hole 214 (see Figure 5). Fig. 3) In some embodiments, the tab 502 optionally extends from the delamination insert 302 by a distance equal to or greater than the thickness of the outer sheet 204. In this way, the tab 502 can completely penetrate the through-hole 214.

[0038] In some embodiments, the delamination insert 302 can optionally be further attached to the outer sheet 204 of the aluminum foam sandwich 200 by bonding the delamination insert 302 to the outer sheet 204. In some embodiments, one or more welds 504 are optionally made across the through-hole 214, the tab 502 of the delamination insert 302, and the outer sheet 204. In some embodiments, one or more welds 504 are optionally made on the outer sheet 204 across all exposed tabs 502.

[0039] Fig. Figure 6 is a rear view of the aluminum foam sandwich 200 after bonding the delamination insert 302 to the inner sheet 202. The delamination insert 302 can be attached to the inner sheet 202 in a similar manner to how it was previously described with regard to the outer sheet 204 (see Figure 6). Fig. 5) For example, in some embodiments, the delamination insert 302 can optionally be further attached to the inner sheet 202 of the aluminium foam sandwich 200 by forming one or more welds 504 between and / or over the section 406 of the delamination insert 302 and the inner sheet 202 (see Fig. 6).

[0040] With reference to Fig. Figure 7 is a flowchart 700 for the provision of a curved aluminum foam sandwich with a delamination insert according to one embodiment. The flowchart 700 is presented with reference to Fig. 1 to 6 described and may contain further details, in Fig. 7 steps not shown. Fig. Although the 7 blocks shown are presented in a specific order, they can be rearranged, subdivided and / or combined.

[0041] In block 702, an inner sheet is formed. In block 704, an outer sheet is formed. In some embodiments, one or more through-holes are formed in the outer sheet. In block 706, a core is formed between the inner and outer sheets. In some embodiments, the core comprises a porous foam core, the inner sheet comprises aluminum, and the outer sheet comprises aluminum. In some embodiments, the method includes receiving a prefabricated, flat aluminum foam sandwich comprising the formed inner sheet, outer sheet, and core.

[0042] In some embodiments, a flat aluminum foam sandwich is cut and / or otherwise processed to obtain an initial, flat partition. In some embodiments, the cutting / forming process (also referred to as "rough-in") includes texturing both sheets and the core. After the initial rough-in, the inner sheet is further cut, for example, at a 45-degree miter, and sections of the foam core are removed (scraped, cut, sanded, ground, etc.) so that the flat aluminum foam sandwich can be folded. The result is a curved aluminum foam sandwich. The outer sheet of the aluminum foam sandwich is not cut in this process. In other words, the outer sheet, and consequently the curved aluminum foam sandwich itself, remains a single, continuous piece (although the outer sheet is formed by the initial rough-in).

[0043] In block 708, a delamination insert is positioned at a bend between the inner and outer sheets, such that the side walls of the delamination insert are in direct contact with sections of the core and the inner sheet. In some embodiments, the delamination insert includes a tab positioned to extend through the through-hole.

[0044] The procedure may further include the application of a weld seam over the through hole and in direct contact with the tab of the delamination insert.

[0045] In some embodiments, a leading edge of the delamination insert is in direct contact with a surface of the outer sheet. In some embodiments, a trailing edge, opposite the leading edge of the delamination insert, extends beyond a surface of the inner sheet.

[0046] In some embodiments, sections of the inner sheet and sections of the porous foam core are removed to expose the surface of the outer sheet. In some embodiments, the sections of the inner sheet and the sections of the porous foam core are removed at an angle of 45 degrees to the surface of the outer sheet.

Claims

[1] Curved aluminium foam sandwich (200), comprising: an inner sheet (202); an outer sheet (204) with a through hole (214); a core (206) between the inner sheet (202) and the outer sheet (204); and a delamination insert (302) at a bending point (210) between the inner sheet (202) and the outer sheet (204), such that side walls of the delamination insert (302) are in direct contact with the core (206) and the inner sheet (202), wherein the delamination insert (302) comprises a tab (502) which is positioned to extend through the through hole (214). [2] Curved aluminum foam sandwich (200) according to claim 1, wherein the core (206) comprises a porous foam core (206), the inner sheet (202) comprises aluminum and the outer sheet (204) comprises aluminum. [3] Curved aluminium foam sandwich (200) according to claim 1, further comprising a weld seam (504) over the through hole (214) which is in direct contact with the tab (502) of the delamination insert (302). [4] Curved aluminium foam sandwich (200) according to claim 1, wherein a front edge (408) of the delamination insert (302) is in direct contact with a surface of the outer sheet (204). [5] Curved aluminium foam sandwich (200) according to claim 4, wherein sections of the inner sheet (202) and sections of the core (206) are removed to expose the surface of the outer sheet (204). [6] Curved aluminium foam sandwich (200) according to claim 5, wherein the sections of the inner sheet (202) and the sections of the core (206) are removed at an angle of 45 degrees to the surface of the outer sheet (204). [7] Curved aluminium foam sandwich (200) according to claim 4, wherein a trailing edge (410) opposite the front edge (408) of the delamination insert (302) extends beyond a surface of the inner sheet (202). [8] Vehicle (100), comprising: a component (108) comprising a curved aluminium foam sandwich (200), wherein the curved aluminium foam sandwich (200) comprises the following: an inner sheet (202); an outer sheet (204) with a through hole (214); a core (206) between the inner sheet (202) and the outer sheet (204); and a delamination insert (302) at a bending point (210) between the inner sheet (202) and the outer sheet (204), such that side walls of the delamination insert (302) are in direct contact with the core (206) and the inner sheet (202), wherein the delamination insert (302) comprises a tab (502) which is positioned to extend through the through hole (214). [9] Vehicle (100) according to claim 8, wherein the core (206) comprises a porous foam core (206), the inner sheet (202) comprises aluminium and the outer sheet (204) comprises aluminium. [10] Vehicle (100) according to claim 8, further comprising a weld (504) over the through hole (214) which is in direct contact with the tab (502) of the delamination insert (302).

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