This application is the National Phase, under 35 U.S.C. ยง 371(c), of International Application No. PCT/EP2020/079786, filed Oct. 2, 2020, which claims priority from European Application No. EP 19205020.1, filed Oct. 24, 2019. The disclosures of all the referenced applications are incorporated herein by reference in their entirety.
Not Applicable.
Embodiments herein relate to composite sandwich components and methods of manufacturing such composite sandwich components.
The use of composite sandwich construction is widely used in order to achieve light, strong and stiff components and structures. Composite sandwich technology is used in many industry sectors such as renewable energy, marine, transport, aerospace, industry, building and many more fields of industry.
Typically, composite sandwich components are manufactured from a core structure that is provided with a top reinforcement layer and a bottom reinforcement layer. The components are arranged as a sandwich in a mould to ensure the geometry of the component, i.e. in order to enable the component to obtain an intended shape, whereupon liquid resin is provided to the arranged components, infusing the reinforcement layers. When the resin hardens, the top and bottom reinforcement layers harden and become firmly fixed to the core structure and a composite sandwich component has been created. The composite sandwich component is then removed from the mould and it is ready for further use in the various fields of technology as mentioned above.
When producing a composite sandwich component, for example with the so-called Resin Transfer Moulding (RTM) or Vacuum Assisted Resin Transfer Moulding (VARTM) or Vacuum Infusion Process (VIP) production process, the liquid and flowing resin has to reach and saturate the reinforcement layers on both the top and bottom sides of the core structure. The resin distribution over the surface areas is typically enabled by a resin transfer aid such as grooves in the core surface, a sacrificial flow mesh or an interlaminar flow media.
However, a problem associated with such processes is that, during infusion of most sandwich components, regardless of industry sector, the resin flow can't be directly fed to the mould side of the sandwich. Therefore a plurality of perforations of the core structure are needed to ensure resin flow from the top reinforcement layer, onto which the resin is provided, to the mould side reinforcement layer, i.e. the bottom reinforcement layer. Typically a number of 1200-2500 perforations per square meter is used in prior art production of composite components.
A drawback associated with the requirement for such perforations is that small diameter perforations are difficult to produce on thick core materials and the actual creation of such perforations has a non-negligible production cost. Furthermore, during the resin infusion process the perforations are filled with resin and hardened resin remain in the perforations for the lifetime of the final sandwich component. Such resin filled perforations, while being essential for the process of manufacturing prior art composite sandwich components, they have negligible contribution to the structural properties of the component and, consequently, the resin in the perforations can be seen as waste, with associated cost, as well as an added non-desirable weight of the component.
In view of the above, an object of the present disclosure is to overcome drawbacks related to prior art composite sandwich components and methods of manufacturing composite sandwich components.
Such an object is achieved in a first aspect by a method of manufacturing a composite sandwich component. The composite sandwich component comprises a first core structure, a second core structure, a third core structure, a top reinforcement layer and a bottom reinforcement layer. Each of the first, second and third core structures is made of polymer foam or wood, and each of the first, second and third core structures has a respective top surface, a bottom surface, a left edge surface and a right edge surface.
The method of the first aspect comprises the steps of configuring surfaces of the first, second and third core structures with grooves such that:
The method of the first aspect further comprises the steps:
The object of the present disclosure is achieved in a further aspect by a method of manufacturing a composite sandwich component, the composite sandwich component comprising a first core structure, a second core structure, a top reinforcement layer and a bottom reinforcement layer. Each of the first and second core structures is made of polymer foam or wood, and each of the first and the second core structures has a respective top surface, a bottom surface, a left edge surface and a right edge surface.
The method of this further aspect comprises the steps of configuring surfaces of the first and second core structures with grooves such that:
The object of the present disclosure is achieved in yet a further aspect by composite sandwich component comprising a first core structure, a second core structure, a third core structure, a top reinforcement layer and a bottom reinforcement layer. Each of the first, second and third core structures are made of polymer foam or wood, and each of the first, second and third core structures has a respective top surface, a bottom surface, a left edge surface and a right edge surface, wherein:
The object of the present disclosure is achieved in yet a further aspect by composite sandwich component comprising a first core structure, a second core structure, a top reinforcement layer and a bottom reinforcement layer. Each of the first and second core structures are made of polymer foam or wood, and each of the first and the second core structures has a respective top surface, a bottom surface, a left edge surface and a right edge surface, wherein:
With regard to the chamfers of the intersections of surfaces as summarized above, they may comprises any of:
That is, methods of manufacturing a composite sandwich components and composite sandwich components as summarized above overcome drawbacks in the prior art. For example, the large number of resin filled perforations that are unavoidable when manufacturing prior art composite sandwich components is avoided.
In other words, as summarized in the various aspects, by configuring top, bottom and side surfaces with grooves and configuring intersections of top/bottom and side surfaces with a chamfer, the flow of resin from the resin feed area to the bottom surfaces is facilitated. Resin that is fed and permeates the top reinforcement layer gathers in the chamfer in the top surface intersection and is transported by a pressure gradient via the side surface grooves to the chamfer in the bottom surface intersection. Having gathered in the chamfers in the top and bottom surfaces intersection, the resin flows along the grooves in the top and bottom surfaces, the flow being driven by pressure gradients obtained by the evacuation of air from the enclosure in which the components are arranged. The resin flow driven by the pressure gradients is not only along the grooves in the top and bottom surfaces, but also in directions transverse to the grooves such that the top and bottom surfaces with reinforcement layers become completely saturated with resin and thereby, when the resin has hardened, merging the single materials into a composite sandwich component.
An advantage of such methods of manufacturing a composite sandwich components and composite sandwich components as summarized above is a significant reduction of waste resin, with associated reduced cost as well as a minimization of non-desirable weight of the component.
It is to be noted that the various components of the composite sandwich component 100 in
Each of the first, second and third core structures 101, 102, 103 is made of polymer foam or wood and each of the first, second and third core structures 101, 102, 103 has a respective top surface 1011, 1021, 1031, a bottom surface 1012, 1022, 1032, a left edge surface 1013, 1023, 1033 and a right edge surface 1014, 1024, 1034. Furthermore, the top surface 1011 of the first core structure 101 is configured with a plurality of grooves 115 extending from the right edge surface 1014, the bottom surface 1012 of the first core structure 101 is configured with a plurality of grooves 115 extending from the right edge surface 1014, the top surface 1021 of the second core structure 102 is configured with a plurality of grooves 115 extending from the left edge surface 1023, the bottom surface 1022 of the second core structure 102 is configured with a plurality of grooves 115 extending from the left edge surface 1023, the left edge surface 1033 of the third core structure 103 is configured with a plurality of grooves 116 extending from the top surface 1031 to the bottom surface 1013 of the third core structure 103, and the right edge surface 1034 of the third core structure 103 is configured with a plurality of grooves 116 extending from the top surface 1031 to the bottom surface 1013 of the third core structure 103.
Although the grooves 115 on the top surfaces 1011, 1021 and the corresponding grooves (not visible) on the bottom surfaces 1012, 1022 on the first and second core structures 101, 102 are illustrated as being parallel and continuing across the respective surface to respective edge surface 1013, 1024, other configurations of the grooves 115 are possible as will be exemplified below. Moreover, although
At least one intersection of a top surface 1011, 1021, 1031 and an edge surface 1014, 1023, 1033, 1034 and at least one intersection of a bottom surface 1012, 1022, 1032 and an edge surface 1014, 1023, 1033, 1034 are configured with a chamfer 123. The composite sandwich component 100 exemplified in
The first, second and third core structures 101, 102, 103 are arranged in relation to each other such that the left edge surface 1033 of the third core structure 103 abuts the right edge surface 1014 of the first core structure 101 and such that the right edge surface 1034 of the third core structure 103 abuts the left edge surface 1023 of the second core structure 102.
The first, second and third core structures 101, 102, 103 are arranged on the bottom reinforcement layer 112, and the top reinforcement layer 111 is arranged on the top surfaces of the first, second and third core structures 101, 102, 103.
Although not visible in
Each of the first and second core structures 201, 202 being made of polymer foam or wood, each of the first and the second core structures 201, 202 having a respective top surface 2011, 2021, a bottom surface 2012, 2022, a left edge surface 2013, 2023 and a right edge surface 2014, 2024. Furthermore, the top surface 2011 of the first core structure 201 is configured with a plurality of grooves 215 extending from the right edge surface 2014, the bottom surface 2012 of the first core structure 201 is configured with a plurality of grooves 215 extending from the right edge surface 2014, the top surface 2021 of the second core structure 202 is configured with a plurality of grooves 215 extending from the left edge surface 2023, and the bottom surface 2022 of the second core structure 202 is configured with a plurality of grooves 215 extending from the left edge surface 2023. In the specific example of
Although the grooves 215 on the top surfaces 2011, 2021 and the corresponding grooves (not visible) on the bottom surfaces 2012, 2022 on the first and second core structures 201, 202 are illustrated as being parallel and continuing across the respective surface to respective edge surface 2013, 2024, other configurations of the grooves 215 are possible as will be exemplified below. Moreover, although
At least one intersection of a top surface 2011, 2021 and an edge surface 2014, 2023 and at least one intersection of a bottom surface 2012, 2022 and an edge surface 2014, 2023 are configured with a chamfer 223. The composite sandwich component 200 exemplified in
The first and second core structures 201, 202 are arranged in relation to each other such that the right edge surface 2014 of the first core structure 201 abuts the left edge surface 2023 of the second core structure 202.
The first and second core structures 201, 202 are arranged on the bottom reinforcement layer 212, and the top reinforcement layer 211 is arranged on the top surfaces of the first and second core structures 201, 202.
Although not visible in
With regard to which material or materials the core structures 101, 102, 103, 201, 202 are made of, any of the first core structure 101, 201, the second core structure 102, 202 and the third core structure 103 may be made of any polymeric foam material or wood based material such as any of the materials Polyvinyl chloride (PVC), Polyethylene terephthalate (PET), Polyethersulfone (PES), Polymethacrylimide (PMI), Styrene acrylonitrile (SAN), Polyurethane, Balsa wood and Plywood.
With regard to which material or materials the reinforcement layers 111, 112, 211, 212 are made of, any of the top reinforcement layer 111, 211 and the bottom reinforcement layer 112, 212 is made of any reinforcement material such as any of the materials glass fibre material, carbon fibre material, natural fibre material, thermoplastic fibre material, aramid fibre material and ceramic material.
As exemplified in
Moreover, although not illustrated, grooves 115, 116, 215, 216 may be less straight than illustrated in the figures herein. For example, examples of core structures include those having more or less curved or meandering grooves, which may be useful in cases where the structures have more complex geometry than those structures exemplified herein.
Furthermore, with regard to the grooves 115, 116, 215, 216, reference is made to
Any of the grooves 115, 116, 215, 216 may be configured with a depth 1151, 1161 that is in the interval 1.0 to 2.5 mm, preferably in the interval 1.3 to 2.0 mm, and a width 1152, 1162 that is in the interval 1.0 to 2.5 mm, preferably in the interval 1.3 to 2.0 mm.
Moreover, at least two grooves among the grooves 115, 116, 215, 216 may be configured essentially in parallel with each other and have an average distance from each other that is in the interval 15 to 35 mm, preferably in the interval 20 to 25 mm. However, as pointed out above, core structures may be configured with curved or meandering grooves. The average distances exemplified above are applicable also for such curved or meandering grooves.
Groove dimensions and spacing between grooves can be adjusted to suit production with specific resins and fibre reinforcements as well as sandwich component size and geometry.
As indicated above in connection with the description of
With reference to
Any of the chamfers 123, 223 at any intersection of surfaces may be configured with a depth 1231, 2231 that is in the interval 1.5 to 3.0 mm, preferably in the interval 1.7 to 2.5 mm, and a width 1232, 2232 that is in the interval 1.0 to 2.5 mm, preferably in the interval 1.3 to 2.0 mm.
Turning now to
The method comprises a plurality of steps as follows:
Step 501
A surface configuration step that comprises configuring surfaces of the first, second and third core structures 101, 102, 103 with grooves 115, 116 such that:
Step 503
A chamfering step that comprises chamfering at least one intersection of a top surface 1011, 1021, 1031 and an edge surface 1014, 1023, 1033, 1034 and at least one intersection of a bottom surface 1012, 1022, 1032 and an edge surface 1014, 1023, 1033, 1034.
For example, the chamfering step 503 may comprises chamfering any of:
Step 505
An arrangement step comprising arranging the first, second and third core structures 101, 102, 103 in relation to each other such that the left edge surface 1033 of the third core structure 103 abuts the right edge surface 1014 of the first core structure 101 and such that the right edge surface 1034 of the third core structure 103 abuts the left edge surface 1023 of the second core structure 102.
Step 507
An arrangement step comprising arranging the first, second and third core structures 101, 102, 103 on the bottom reinforcement layer 112.
Step 509
An arrangement step comprising arranging the top reinforcement layer 111 on the top surfaces of the first, second and third core structures 101, 102, 103.
The arrangement steps 505, 507 and 509 may involve the use of kitted (i.e. pre cut) components to increase efficiency.
Step 511
An enclosing step comprising enclosing the arranged 505, 507, 509 first, second, third core structures 101, 102, 103 and top and bottom reinforcement layers 111, 112 in an enclosure 160.
The enclosure 160 is air-tight and it is configured such that it will withstand the evacuation of air without being damaged.
Step 513
A feeding step comprising feeding liquid resin onto the top reinforcement layer 111 in a resin feed area 170 above which the left edge surface 1033 of the third core structure 103 abuts the right edge surface 1014 of the first core structure 101 and the right edge surface 1034 of the third core structure 103 abuts the left edge surface 1023 of the second core structure 102.
The feeding of resin may advantageously take place from a resin reservoir 161 via a resin feed line 172, e.g. a spiral hose or profile as is known in the art, and although not illustrated in
Step 515
An evacuation step comprising, while the feeding in step 513 of liquid resin continues, evacuating the enclosure 170 of air, whereby the liquid resin is transported horizontally along the grooves 115 in the top surfaces 1011, 1021 of the first and second core structures 101, 102, respectively, and whereby the liquid resin is transported vertically along the grooves 116 in the left and right edge surfaces 1033, 1034 of the third core structure 103 and horizontally along the grooves 115 in the bottom surfaces 1012, 1022 of the first and second core structures 101, 102.
The evacuation of air from the air-tight enclosure 160 may be realized by means of an evacuation pump 162 connected to the enclosure 160 at points on the enclosure 160 distributed in such a manner that a level of vacuum is obtained.
As illustrated schematically in
Turning now to
The method comprises a plurality of steps as follows:
Step 601
A surface configuration step that comprises configuring surfaces of the first and second core structures 201, 202 with grooves 215, 216 such that:
Step 603
A chamfering step that comprises chamfering at least one intersection of a top surface 2011, 2021 and an edge surface 2014, 2023 and at least one intersection of a bottom surface 2012, 2022 and an edge surface 2014, 2023.
For example, the chamfering step 603 may comprises chamfering any of:
Step 605
An arrangement step comprising arranging the first and second core structures 201, 202 in relation to each other such that the right edge surface 2014 of the first core structure 201 abuts the left edge surface 2023 of the second core structure 202.
Step 607
An arrangement step comprising arranging the first and second core structures 201, 202 on the bottom reinforcement layer 212.
Step 609
An arrangement step comprising arranging the top reinforcement layer 211 on the top surfaces of the first and second core structures 201, 202.
Similar to the examples described above, the arrangement steps 605, 607 and 609 may involve the use of kitted (i.e. pre cut) components to increase efficiency.
Step 611
An enclosing step comprising enclosing the arranged 605, 607, 609 first and second core structures 201, 202 and top and bottom reinforcement layers 211, 212 in an enclosure 160.
The enclosure 160 is air-tight and it is configured such that it will withstand the evacuation of air without being damaged.
Step 613
A feeding step comprising feeding liquid resin onto the top reinforcement layer 211 in a resin feed area 170 above which the right edge surface 2014 of the first core structure 201 abuts the left edge surface 2023 of the second core structure 202.
The feeding of resin may advantageously take place from a resin reservoir 161 via a resin feed line 172, e.g. a spiral hose or profile as is known in the art, and although not illustrated in
Step 615
An evacuation step comprising, while the feeding in step 613 of liquid resin continues, evacuating the enclosure 160 of air, whereby the liquid resin is transported horizontally along the grooves 215 in the top surfaces 2011, 2021 of the first and second core structures 201, 202, respectively, and whereby the liquid resin is transported vertically along the grooves 216 in the right and left edge surfaces 2014, 2023 of the first and second core structures 201, 201, respectively, and horizontally along the grooves 115 in the bottom surfaces 2012, 2022 of the first and second core structures 201, 202, respectively.
As illustrated schematically in
Finally, in order to illustrate the advantage of weight reduction obtained by the methods of manufacturing and the composite sandwich components of the present disclosure, reference is made to table 1. Table 1 illustrates results from theoretical calculations of comparisons of resin uptake at different thicknesses of composite sandwich components according to the present disclosure with a typical prior art component. Resin uptake is a value that represents the resin captured in surfaces with cell structure and cavities from grooves and perforations.
Specifically, the composite sandwich components according to the present disclosure that are used in the calculations are foam cores with density of 60 kg/m3 having a surface absorption of 500 g/m2, a chamfer profile of 2 mm width by 2 mm depth, a groove profile of 2 mm width by 2 mm depth and a 20 mm groove spacing.
The comparison prior art components are similar foam cores with density of 60 kg/m3 having a groove profile of 2 mm width by 2 mm depth, a 20 mm groove spacing and perforations having a 2 mm diameter arranged in a cross pattern with a 20 mm by 20 mm distance.
Table 1 shows the results in terms of calculated weights (kg/m2) of composite sandwich components manufactured as described herein and calculated weights (kg/m2) of typical prior art composite sandwich components of different thicknesses (mm). The weight differences (kg/m2) at the bottom of the table illustrate that a significant weight saving is obtained when manufacturing composite sandwich components as described herein.
Number | Date | Country | Kind |
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19205020 | Oct 2019 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/079786 | 10/22/2020 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2021/078877 | 4/29/2021 | WO | A |
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Entry |
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International Search Report on corresponding PCT application (PCT/EP2020/079786) from International Searching Authority (EPO) dated Jan. 14, 2021. |
Written Opinion on corresponding PCT application (PCT/EP2020/079786) from International Searching Authority (EPO) dated Jan. 14, 2021. |
Number | Date | Country | |
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20220388270 A1 | Dec 2022 | US |