KR20100021174A - Light weight sandwich panels having foam core reinforced by truss type periodic cellular material and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A lightweight sandwich panel with a foam core reinforced by a periodic cellular material of a truss shape, and a manufacturing method thereof are provided to minimize flaws by arranging porous materials between an upper sheathing and a lower sheathing. CONSTITUTION: A lightweight sandwich panel with a foam core reinforced by a periodic cellular material of a truss shape comprises a three-dimensional truss shaped porous material, a foam core(400), an upper sheathing(100), and a lower sheathing(200). Multiple cells are formed inside of the three-dimensional truss shaped porous material. The foam core is filled with the cells. The upper sheathing and the lower sheathing are arranged in the top and bottom of the three-dimensional truss shaped porous material, and coupled with the foam core.

Description

LIGHT WEIGHT SANDWICH PANELS HAVING FOAM CORE REINFORCED BY TRUSS TYPE PERIODIC CELLULAR MATERIAL AND MANUFACTURING METHOD OF THE SAME}

The present invention relates to a light weight sandwich plate and a method of manufacturing the same, and more particularly, to a foam core material reinforced with a regular porous material in the form of a three-dimensional truss, thereby improving both the strength and thermal insulation performance, and the sound insulation and vibration absorption ability of the intermediate material. The present invention relates to a lightweight sandwich board having a foam core reinforced with a periodic porous material in the form of a truss to be improved, and a method of manufacturing the same.

As is well known, sandwich plate (plate structure) is composed of the upper and lower face sheet and the intermediate material (Core) disposed therebetween, the upper and lower face plate is composed of a high strength / density material, The intermediate material consists of low density porous material or lattice material such as styrofoam.

For example, FIG. 1 illustrates the shape of several sandwich plates with the lattice intermediate described above.

However, such a lattice-shaped intermediate material or a porous material has a disadvantage in that space utilization is difficult because the inside is composed of a plurality of blocked cells.

In this connection, a periodic porous material in the form of a truss has recently been introduced as a new intermediate material (H. N. G. Wadley, N. A. Fleck, A. G. Evans, 2003, Composite Science and Technology, Vol. 63, pp. 2331 ~ 2343).

Here, the periodic porous material in the form of truss refers to a material having a uniform size, shape, and arrangement of internal cells.

In particular, the truss structure designed for optimum strength through precise calculation has the advantage that space can be utilized because the interior is open while having mechanical properties comparable to Honeycomb lattice.

In addition, the most common type of truss is a pyramid truss, which is generally composed of four regular triangular lattice lines and a square lattice bottom (or top) plane to form a rectangular plate structure. It is advantageous.

In addition, another truss structure may include an octet truss (R. Buckminster Fuller, 1961, US Patent 2,986,241) in which a tetrahedron and an octahedron are combined, in which each element forms an equilateral triangle.

Another truss structure is Kagome truss (S. Hyun, AM Karlsson, S. Torquato, AG Evans, 2003, Int J. of Solids and structures, Vol. 40, pp.6989-6998). This was accomplished by modifying the octet truss in the 21st century.

2 (a), 2 (b) and 2 (c) illustrate the shape of a sandwich plate material having these pyramids, octets, and kagome truss structures as intermediate materials and having upper and lower face materials attached thereto.

Compared to the pyramid truss (a) and the octet truss (b), the kagome truss (c) illustrated in FIG. 2 has less stiffness change in structure along the direction, resistance to buckling, stability of deformation after buckling, and energy absorption. It is known that the ability is excellent.

On the other hand, the expanded metal mesh process is a very efficient method for processing a metal plate in the form of a wire mesh has been disclosed a method for producing a periodic porous material in the form of truss by bending the wire mesh produced through this.

For example, Korean Patent No. 0700211, No. 0589619, Patent Application No. 2007-0136648, Patent Application No. 2006-0016020, etc., all of them are methods for producing a periodic porous material applying the expanded metal mesh process 3 to 6 show the shape of the periodic porous material by these disclosed techniques.

On the other hand, the wire is easy to mass production, processing and high strength, and a good example is the piano wire, recently focusing on the characteristics of the wire to produce a truss-shaped periodic porous material made of wire material This has been disclosed.

For example, Korean Patent Nos. 0566729, 0633657, 0700212, 0767186, and the like, all of which relate to a method of manufacturing a periodic porous material using a wire material. The shape of the periodic porous material by the disclosed techniques is shown.

In addition, if a wire is made of a fiber reinforced plastic composite material and then used, a lighter truss-shaped periodic porous material may be realized. Also, the truss-shaped periodic porous material may be realized. Since the material is low in density and high in strength, it will be of high value as a core for sandwich boards.

However, such a porous material has a small cross section of the truss element constituting the porous material, so that the point of attachment to the upper and lower face members may be weak.

Particularly, in the case of a metal material, brazing or soldering is relatively easy by using a mixture of a filler metal and a flux in the form of a paste, and the bonding strength thereof is also high, but the fiber reinforced composite material (Fiber Reinforced) The periodic porous material made of composite material is difficult to bond with the upper and lower face materials except for the conventional resin bonding, and the strength of the resin bonding is also insufficient.

In addition, since soldering and brazing are all performed at a high temperature of a certain temperature or higher, there is a possibility that the strength of the metal material used, thermal deformation, or the like may be caused.

On the other hand, as a light weight sandwich plate widely used in the past, the upper and lower face material is attached to both sides of the foam core is most common, which is due to the low manufacturing cost and excellent thermal insulation performance.

However, such a lightweight sandwich board has a limitation that its use is very limited because it is not used for structural purposes but is used for simple partitions or temporary structures because of its low strength.

As another example, for example, WO95 / 03170 uses a foam core as a sandwich plate core material, and stitches the reinforced upper and lower sheets of reinforced sheets on the laminated upper and lower sheets to improve strength, and buckles them in the form of x-bands. It is disclosed that a lightweight sandwich structure in which the strength is improved by buckling is formed.

However, in this case, since the work process is complicated, and the laminated sheet must be a synthetic resin in order to buckle with the reinforcing fiber, the field of application is very narrow and extremely limited, which is far from the field of application of the present invention.

As another example, Japanese Patent Application Laid-Open No. Hei 6-129008 and US Patent Application 2001-0045077, but in the former case, the truss structure itself disposed between the upper and lower materials is not only two-dimensional but also through a bolt or welding method. Since it is a sandwich panel structure, most of the elements used as core materials are steel pipes or section steels, so it is difficult to reduce the weight. In the latter case, the truss structure itself is two-dimensional and is simply bonded using cementitious adhesive materials. Has a low disadvantage.

As another example, US Patent Application 2002-0170941 and US Patent Application 2006-0163319, which can be seen that the structure is a high-strength realization in that both form a three-dimensional dross structure.

However, in the case of the former, when the truss core is fixed to the upper and lower materials, an electrode is formed by weaving a wire composed of any one of Al, Cr, Cu, Fe, Mg, Ni, and Ti between the core and the upper and lower materials. Sandwich panel structure is fixed by welding by using multiple spot welding (Multiple Spot Welding) method, but the strength is improved, but the disadvantages in terms of light weight, the workability is very bad, the manufacturing cost increases sharply.

On the other hand, in the latter case, by applying heat or high loads with pins of a particular shape between the truss cores, local joints of the pins and the cores and the upper and lower ashes are made at the same time at multiple points. Although it can be lighter than the former in terms of quality, it is still disadvantageous in terms of light weight in that it adopts alloys (Alloys) mixed with Ti, Al, V, and Ni as fin materials.

The present invention has been made in view of the above-mentioned problems in view of the above-mentioned problems, and reinforces the foam core with a periodic porous material in the form of a truss, but does not join the end face of the small truss element with the upper / lower face member. By allowing the foam cores with much larger area to be bonded to the upper / lower face members, it is possible to improve the strength, insulation, sound insulation, and vibration absorption of the plate through the complementary interaction between the foam core and the truss-shaped periodic porous materials. There is a major problem to provide a lightweight sandwich plate having a foam core reinforced with a periodic porous material in the form of a truss and a method of manufacturing the same.

The present invention is a means for achieving the above object, a three-dimensional truss porous material formed with a plurality of cells therein; An expandable core filled in the cells; Lightweight sandwich plate having a foam core reinforced with a truss-shaped periodic porous material, characterized in that the upper and lower face material is disposed on the upper and lower sides of the porous material having the three-dimensional truss shape, and bonded to the foam core To provide.

At this time, the three-dimensional truss-like porous material is characterized in that any one selected from pyramid truss, octet truss, kagome truss, pseudo-octet truss woven from a continuous wire, pseudo-cargo truss.

In addition, the foam core material is a foamed resin such as foamed polyurethane, foamed polyethylene, foamed polystyrene; Foam metal; It is also characterized by any one selected from foamed inorganic materials.

In addition, the present invention provides a means for achieving the above object, the step of manufacturing a porous material in the form of a three-dimensional truss formed with a plurality of cells therein; Disposing a thin upper face and a lower face on upper and lower sides of the porous material having a three-dimensional truss shape; Filling the foam core by injecting the foamed material into the cells and foaming the foamed material at the same time as the upper face and the lower face in contact with and fixed to the upper and lower surfaces of the porous material having a three-dimensional truss shape; ; Method for producing a lightweight sandwich plate having a foam core reinforced with a truss-shaped periodic porous material characterized in that the bonding step to maintain a certain time after the filling step so that the foamed core material is firmly bonded to the upper and lower face material. to provide.

Furthermore, the present invention provides a means for achieving the above object, the step of manufacturing a porous material in the form of a three-dimensional truss formed with a plurality of cells therein; Filling the foam core with the foam by injecting the foam material into the cells and foaming the foam material after the injection; After the filling step, the upper face and the lower face are placed in contact with the upper and lower surfaces of the porous material having a three-dimensional truss shape, and the reinforcement is performed by the periodic porous material of the truss shape, comprising a joining step of attaching the foamed core material to the adhesive. It is also possible to provide a method for producing a lightweight sandwich board having a foamed core material.

At this time, in the filling step of the manufacturing method of the light weight sandwich plate, a heating step of completely foaming the unfoamed foam material may be further performed by adding heat after the filling is completed.

The present invention has the following effects.

First, the strength of the joint is high and resistant to defects because the foam core, which has a much larger area, is joined to the upper / lower face material without joining the truss element end with a smaller cross-sectional area to the upper / lower face material.

Secondly, since the joint is wide, sufficient bonding strength can be maintained even with conventional bonding, so that soldering or brazing is not required. Even if this is performed, material weakening or thermal deformation does not occur, and manufacturing cost is low.

Third, sufficient bonding strength can be obtained between the face material and the core material, so that the fiber-reinforced composite material can be used as the basic material of the truss type periodic porous material or the upper / lower face material.

Fourth, if a truss-shaped periodic porous material is placed between the upper and lower face members and the foam material is injected or generated while the position is fixed, the foam material is compressed and hardened to the interface with the upper and lower face members by the foaming pressure. This eliminates the need for a separate joining process and minimizes defects.

Fifth, the strength of the intermediate material is improved through the complementary action of the foam filler and the periodic porous material in the form of truss.

Sixth, since the empty space of the truss-shaped periodic porous material is filled with the foamable filler, convection is suppressed, so that the thermal insulation performance is improved.

Seventh, since the empty space of the truss-shaped periodic porous material is filled with the foamable filler, vibration is suppressed, and the sound insulation and vibration absorption ability are excellent.

Eighth, production costs are reduced and mass production is facilitated by using simple and already established techniques, such as the production of truss-shaped periodic porous materials, filling of effervescent materials, and resin bonding.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment according to the present invention.

The present invention is to provide a lightweight sandwich plate having a high strength and a method of manufacturing the same, for this purpose apart from the structure that is simply attached to the upper / lower face plate on both sides of the foam core material, the foam core material inside the porous material having a three-dimensional truss form And the three-dimensional truss-shaped periodic porous material with the foam core so filled therebetween, wherein the joining with the upper / lower face material is such that the three-dimensional truss-shaped periodic porous material By making it with the foamed core material, it is configured to have a function of improving strength and suppressing buckling.

In this case, the expandable core material may be formed in the form of a foam material is injected at the same time as the foam material is injected into a plurality of cells, that is, the internal hollow space of the periodic porous material in the form of a three-dimensional truss, or after the foam material is injected It may be made in the form of foaming by the heat applied.

In addition, the foamed material constituting the foamed core is preferably a foamed polyurethane, but is not limited thereto, and all foamable materials such as foamed polyethylene, foamed polystyrene, foamed metal, and the like may be used.

All porous materials described below refer to “porous materials in the form of three-dimensional trusses”.

Such high-strength lightweight sandwich plate of the present invention can be manufactured in the form as shown in FIG.

That is, Figure 12 shows one preferred embodiment of the high-strength lightweight sandwich plate according to the present invention, in particular, the present invention is applied to a similar kagome truss structure woven from a continuous wire as disclosed in Patent No. 0708483. .

As shown in FIG. 12, the upper faceplate 100 and the lower faceplate 200 are disposed at a predetermined interval to form a lightweight sandwich plate.

And, between the upper face member 100 and the lower face member 200, if described with reference to the embodiment of the truss-shaped periodic porous material, that is, the embodiment illustrated in FIG. Cargo truss structure 300 is disposed.

At this time, a plurality of cells (C), which is an internal empty space of the similar Kagome truss structure 300 woven with a continuous wire is filled with a foam core 400, for example, foamed polyurethane.

Here, the upper face material 100 and the lower face material 200 is bonded while being in contact with the foamed core material 400, which is a liquid resin in the foaming process is well adhered to the face materials without applying a separate adhesive This is because there is a characteristic.

Thus, the foam core 400, i.e., the foam filler itself, has a very low strength but is filled inside the cell C of the pseudo-cargo truss structure 300 woven from a continuous wire, which is a periodic porous material in the form of a truss. The buckling of the truss elements and local indentation of the upper and lower faceplates 100 and 200 are suppressed, thereby increasing the overall strength of the sandwich plate.

In addition, since the foamed core 400 is hardened while being pressed onto the interface with the upper / lower face members 100 and 200 by the foaming pressure, a separate bonding process for improving the bonding strength is not required, and the bonding defect is also minimized.

In addition, the truss-shaped periodic porous material also includes pseudo-octet truss structures woven from a continuous wire.

This high strength lightweight sandwich board is preferably produced as follows.

13 is an exemplary view showing an example of a method for manufacturing a lightweight sandwich plate according to the present invention.

As shown in FIG. 13, a plurality of roller tables 500 are provided for producing a high strength lightweight sandwich sheet according to the present invention, and the roller tables 500 are continuous wires, which are periodic porous materials in the form of trusses. The pseudo-cargo truss structure 300, which is woven into, is movably disposed in a seated state.

In addition, upper and lower face plates 100 and 200 wound in a roll form are provided on the upper and lower sides of the pseudo-cargo truss structure 300 woven with the continuous wire, and the pseudo-cargo truss structure woven with the continuous wire ( Both sides of the 300 is provided with a foam container 600 for storing the foam material, the foam container 600 is connected to the foam pipe 610, the foam pipe 610 is woven with the continuous wire It is disposed on both sides of the pseudo-kagome truss structure 300.

In addition, a heating means 700 such as a heater may be further provided at the rear side of the foam pipe 610 in the direction in which the high-strength lightweight sandwich plate according to the present invention proceeds, that is, the point past the foam pipe 610. It is to ensure that the foamed material is foamed sufficiently and completely.

At this time, the similar kagome truss structure 300 woven from the continuous wire is in a pre-fabricated state, and this is just an example, it is possible to use all of the generally known periodic three-dimensional truss-shaped porous material of course to be.

In the manufacturing method, first to move the pseudo-cargo truss structure 300 woven with a continuous wire in a state seated on the roller table (500).

In addition, the continuous upper and lower roll 100 and lower face member 200 provided in the upper and lower portions in the middle of conveying the similar kagome truss structure 300 woven with the continuous wire is unfolded and unfolded at the same time The upper and lower ends of the pseudo-kagome truss structure 300 is woven with a wire to be contacted.

At this time, although not shown, it is preferable that a tension roll is installed to support and press the upper face member 100 and the lower face member 200 with a predetermined tension.

In this state, the foamed material stored in the foam container 600, such as polyurethane, is discharged through the foam pipe 610 and each cell of the similar Kagome truss structure 300 woven with the continuous wire (FIG. 12). 'C').

In this case, the foaming pressure and the temperature control may be injected to the foam (C) at the same time as the foaming material, and as shown in the foam, or as shown in the first injection and then later heating means 700 to operate the entire assembly It is also possible to foam the already injected foam material by heating.

In addition, even when the foaming material is injected and foamed at the same time, it is more preferable to completely foam even a small amount or even foamed material by applying heat once again through the heating means 700.

Through this process, the foamed material is completely filled in the entire cell C of the similar Kagome truss structure 300 woven with the continuous wire while foaming, and at the same time between the upper face 100 and the lower face 200 The upper face 100 and the lower face 200 are bonded to the foamed core and the entire surface of the assembly in fact so as to be completely attached to the interface.

On the other hand, although not shown, in another category of the present invention, each cell C of the pseudo-cargo truss structure 300 woven with the continuous wire is first injected with foam material, foamed, and then filled with the upper face material. It may be manufactured in the form of bonding the 100 and the lower face member 200 with an adhesive.

Thus, the assembly, i.e., the lightweight sandwich plate, has sufficient rigidity, the resistance against buckling is also significantly increased, and above all, the lightweight material can be maintained because of the use of the foamed material.

Thereby, the high strength lightweight sandwich board material which this invention aims at can be completed.

1 is a perspective view of a conventional sandwich plate having a lattice-shaped intermediate member,

Figure 2 (a), (b), (c) is a perspective view of a conventional sandwich plate material having a pyramid, an octet and a kagome truss structure as an intermediate material and a face plate attached to the upper and lower, respectively,

3 is a perspective view of a periodic porous material in the form of a similar kagome truss fabricated by applying the expanded metal mesh process disclosed in Patent No. 0700211;

4 is a perspective view of a conventional sandwich plate having an intermediate material of a periodic porous material in the form of a pyramid truss manufactured by applying the expanded metal mesh process disclosed in Patent No. 0589619;

FIG. 5 is a perspective view showing a periodic porous material in the form of a pseudo-cargo truss fabricated through the expanded metal mesh bending process disclosed in Patent Application No. 2007-0136648;

6 is a perspective view showing a periodic porous material in the form of a similar octet truss fabricated using the expanded metal mesh process disclosed in Patent Application No. 2006-0016020;

7 is a perspective view showing a periodic porous material in the form of a multi-layered pseudo-octet truss made of a wire disclosed in Korean Patent No. 0566729,

8 is a perspective view showing a periodic porous material in the form of a one-layer pseudo octet truss made of a wire disclosed in Korean Patent No. 0633657;

9 is a perspective view of a sandwich plate having an intermediate material of a truss-shaped periodic porous material of a one-layer structure made of a wire formed in the form of a coil spring disclosed in Korean Patent No. 0700212;

10 is a perspective view showing a periodic porous material in the form of a similar kagome truss having a multilayer structure made of a wire disclosed in Korean Patent No. 0708483,

11 is a perspective view of a truss-shaped periodic porous material made of a wire disclosed in Korean Patent No. 0767186 disposed on a lower face member;

12 is a perspective view of a high-strength lightweight sandwich plate according to a preferred embodiment of the present invention,

Figure 13 is an exemplary view showing a manufacturing process of high-strength lightweight sandwich plate according to the present invention.

♧ description of the symbols for the main parts of the drawing ♧

100 .... top faceplate 200 .... bottom faceplate

400 .... foamable heart 500 ...... roller table

600 .... foam container 610 ...... foam tube

700 .... heating means

Claims (6)

A three-dimensional truss porous material having a plurality of cells formed therein; An expandable core filled in the cells; Lightweight sandwich plate having a foam core reinforced with a truss-shaped periodic porous material, characterized in that the upper and lower face material is disposed on the upper and lower sides of the porous material having the three-dimensional truss shape, and bonded to the foam core . The method according to claim 1; The porous material having the three-dimensional truss shape is a truss-shaped periodic porous material, characterized in that any one selected from pyramid truss, octet truss, kagome truss, pseudo-octet truss woven from a continuous wire, pseudo-cargo truss Lightweight sandwich plate with foam core reinforced with wood. The method according to claim 1; The foam core material is a lightweight sandwich plate having a foam core material reinforced with a truss-shaped periodic porous material, characterized in that any one selected from foam resin, foam metal, foam inorganic material. Manufacturing a porous material in the form of a three-dimensional truss having a plurality of cells formed therein; Disposing a thin upper face and a lower face on upper and lower sides of the porous material having a three-dimensional truss shape; Filling the foam core by injecting the foamed material into the cells and foaming the foamed material at the same time as the upper face and the lower face in contact with and fixed to the upper and lower surfaces of the porous material; Method of manufacturing a light weight sandwich plate having a foam core reinforced with a truss-shaped periodic porous material characterized in that it is configured to maintain a predetermined time after the filling step so that the foamed core is firmly bonded to the upper face and the lower face. Manufacturing a porous material in the form of a three-dimensional truss having a plurality of cells formed therein; Filling the foam core with the foam by injecting the foam material into the cells and foaming the foam material after the injection; After the filling step, the upper face and the lower face are placed in contact with the upper and lower surfaces of the porous material having a three-dimensional truss shape, and the reinforcement is performed by the periodic porous material of the truss shape, comprising a joining step of attaching the foamed core material to the adhesive. Method for producing a lightweight sandwich board having a foamed core material. The method according to claim 4 or 5; In the filling step, a heating step of completely foaming the unfoamed foam material by further applying heat after the filling is completed, manufacturing a lightweight sandwich plate having a foam core reinforced with a truss-shaped periodic porous material Way.

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