UA72277C2 - Composite structural laminate plate construction and method of its manufacture - Google Patents

Abstract

A composite structural laminate plate construction comprises two outer metal layers, a form between them and an elastomer layer bonded to the outer metal layers and filling the space between them other than that occupied by the form. The form may be foam and may be in partial contact with the metal layers.

Description

The present invention relates to multi-layer sandwich plate structures of composite structural layer material, and in particular to such structures suitable for the construction of both marine and public structures or components in which the traditional method of construction uses high-strength steel or metal plates.

In applications such as ship hulls or bridge decks, the steel plates that make up these structures are generally stiffened to increase stiffness and strength to prevent local longitudinal buckling or local buckling of the plates. Stiffening elements can consist of plates, cold-rolled profiles and graded rolled profiles, which are orthogonally welded to the main bearing plate. As a rule, they are at the same distance and can be oriented in one or two directions, combined with the dimensions in the orthogonal projection of the main plate.

The number, size, location and type depend on the application and the forces that the structure must withstand.

The use of stiffeners requires welding, complicates the production process and adds weight.

Stiffeners, their connection to the base plate or intersection with other main elements of the load-bearing structure often become the source of problems related to material fatigue and corrosion. Complex and overloaded structures, which arise as a result of the connection of plates of increased rigidity, often cannot maintain and provide adequate protection against corrosion.

Spherical metal plastics with improved sound-insulating and heat-insulating properties are known, which are used for cladding or roofing of buildings (see, for example, O5 4698278). Such layer materials mainly use foams or fibrous materials and are not designed or capable of withstanding significant loads, i.e. loads that are significantly greater than their own weight and small loads from local wind and snow. Despite this, the use of a multilayer structure of a steel-polyurethane steel-plastic sandwich was studied for use in ship hulls. The conclusion was that this type of sandwich construction is not suitable because it does not have sufficient graft strength to provide the equivalent longitudinal stiffness that must withstand the loads applied to it.

Patent SV-A-2337022 describes the use of an intermediate layer, which consists of an elastomeric material located between the inner surfaces of the first and second metal layers and attached to them.

The present invention offers an element of structural layered material, which contains: a first metal layer, which has an inner surface and a first outer surface; a second metal layer having a second inner surface and a second outer surface, the second metal layer being spaced from said first metal layer; the profile located between the mentioned first and second inner surfaces; and an intermediate layer consisting of an elastomer located in the spaces between said first and second inner surfaces that are not occupied by said profile and bonded to said first and second inner surfaces.

The first and second metal layers can be considered the face plates of the structure. They also do not have to be parallel and can have varying spacing or shape to provide the required or best performance of the structure.

A layered structural material element according to the invention has a lower average density than prior art elements and is particularly suitable for use in ship hulls or bridge decks, or in other structures where weight is important and where welding between metal layers can be eliminated to reduce costs and solve the problems associated with joining dissimilar metals. In addition, due to the hollow profile, it is easy to ensure the internal distribution of electrical wiring that passes through layered materials or pipeline networks.

Compared to traditional high-strength steel plates, this form of construction provides longitudinal and transverse stiffness and strength, reduces material fatigue problems, significantly reduces stress concentration, improves thermal and acoustic insulation, and provides vibration damping. The layered material provides a structural system that acts as a crack-inhibiting layer that can join two dissimilar metals without welding or galvanic vapor formation.

It is believed that the profile is not load-bearing and simply provides volumes of precise shape, dimensions, which are located in a defined place, in which the core layer of elastomer is not required for the operation of the structure.

The space not occupied by the profile is filled with elastomeric material. The amount, shape and location of the elastomer between the metal layers depends on the specific application and purpose, so that, together with the metal face plates, they can withstand all the acting forces to which the plate from the composite structural layer-by-layer material is subjected. It is assumed that there is a sufficient adhesion surface between the elastomer and the metal plates to transfer the resulting shear forces. In some cases, the use of welding intermediate metal plates or sections can be eliminated. In addition, the interlayer must have the design and material characteristics (yield strength, modulus of elasticity, ductility, stiffness, elasticity, thermal and acoustic characteristics, damping characteristics and vibration characteristics) to provide the structural characteristics required for the application. For example, where the ability to withstand shock loads and absorb energy is important, the interlayer will be designed to help relieve the stress and stiff membrane effect in the metal faceplates, as well as increase the puncture strength.

Examples of implementation of the invention may include metal plates or sections inserted into the intermediate layer or bonded to the intermediate layer to increase stiffness against shear, bending and transverse stiffness and load distribution. The location, size and number are selected depending on the load and requirements placed on the structure. Plates or sections can have longitudinal or transverse directions, or both directions. Providing additional stiffness thus has the advantage that additional plates or sections do not need to be welded to the metal layers; displacement transfer between metal plates or sections and metal layers is provided by the adhesion between the elastomer (mainly) and the profile (additionally) and the metal plates or sections.

The present invention also offers a method of manufacturing an element from a structural layer-by-layer material, which includes the stages of: performing the first and second layers, located at a distance from each other and separated by a profile that is in partial contact with both metal layers located in a cavity that is formed between two plates, while the mentioned profile partially fills the mentioned cavity; pouring non-hardened elastomer into the mentioned cavity; and curing said elastomer in such a way as to ensure its adhesion to said metal layers. performing a profile in contact with metal layers allows easy assembly of layer-by-layer materials within the required dimensional accuracy.

Examples of implementation of the invention will be described below with reference to the corresponding drawings, in which:

Fig. 1 is a schematic side view in cross-section of a composite structural layered element according to the invention, showing several different profiles;

Fig. 2. depicts a longitudinal section of the same component structural layer-by-layer element according to the invention;

Fig. 3 shows a cross-sectional view of the second example of the implementation of the invention;

Fig. 4 shows a cross-sectional view of the third example of the implementation of the invention with a bent section;

Fig. 5 shows a cross-sectional view of the fourth example of the implementation of the invention.

In the drawings, the same parts are marked with the same numerical positions.

Fig. 1 is a cross-sectional view of a layered element according to the present invention.

The layered element contains the first outer layer 1, the profile 10, the intermediate layer 20 and the second outer layer 2.

The profile 10 can be in partial contact with the outer layers 1 and 2 in the areas marked by pos. 15. The intermediate layer 20 has a bond with each of the first and second outer layers 1 and 2 of sufficient strength to carry shear loads between the outer layers, thus forming a composite structural element capable of withstanding a load well in excess of its own weight.

The exact weight a component must support will depend on where it is used.

The ratio of the volume of the profile 10 to the volume of the intermediate layer 20 is selected in accordance with the required physical properties. Such physical properties may include strength, stiffness, or density.

The profile 10 contains several subsections 11, which are interconnected by elements 12 of interconnection. The sub-sections 11 are generally of the same shape and are uniformly spaced, as shown in Fig. 3 or 4 for flat or bent sections. The elements 12 are interconnected, in fact, parallel to the metal layers 1, 2 (although not necessarily). Elements 12 are interconnected, basically, have a smaller maximum cross-section than subsections 11. It is better when several subsections 11 and elements 12 of interconnection are performed at the same time. The profile 10 can be in contact with the first and second outer layers 1, 2 along the entire edge of the subsection 11 or in the mounting holes 13. In the latter case, a large surface area is provided for the adhesion of the intermediate layer 20 to the first and second layers.

Preferably, there are continuous paths that pass through from the first outer layer 1 to the second outer layer 2 and bypass profile 10. Even more preferably, there are straight paths that pass through from the first outer layer (face plate) 1 to the second outer layer (front plate) 2 and bypass the profile 10, which is optimally perpendicular to the first and second outer layers. The profile can be shaped to form an additional grip surface for the elastomer in the metal face plates.

For example, rows of ribs made of elastomer, which look like ionic columns (columns with a capital), will be visible on the cross-section of the structure.

Profile 10 can be made of any light foam, for example, polyurethane foam (CT), which does not react with metal layers 1, 2 or elastomer. The preferred foam is polypropylene semi-rigid foam having a density greater than 20 kg/m3. It is better when the foam has sufficient rigidity so that the metal layers 1, 2 or the intermediate layer 20 do not compress it. The profile 10 can be formed specifically for this purpose or made in a universal way that provides the necessary thickness, which can be brought (by cutting) to the dimensions that are suitable for the profile 10. Between each of the outer layers, several profiles can be located, which are adjacent to each other . Second examples of implementation can replace profiles with other materials, such as wood or steel small-sized boxes obtained by cold stamping. These profiles will perform the same functions and will have the same characteristics as the described profiles 10. These profiles may also have increased shear stiffness and bending stiffness.

As can be seen from Fig. 3 or 4, the profile 10 may consist of a regular matrix of subsections connected to each other at defined intervals. Structural layer-by-layer material made in this way will have uniform properties throughout the element. Alternatively, as shown in Figure 1, the size, shape, and spacing of the subsections may vary. The elements 12 of the interconnection also do not necessarily have to be at the same distance from each other. Any of the shapes of subsection 11 can be selected, and even hollow shapes. These options are chosen according to the required physical properties of the element in a particular case. The provision of cavity elements 12 of the interconnection or cavity subsections 11 allows you to perform the internal distribution of electrical wiring or a network of pipelines.

The function of the profile 10 is not related to the load-bearing capacity, but is a convenient way of creating cavities in the intermediate layer 20 in areas where the overall load-bearing capacity of the elastomer 20 is not required in the space between the first inner surface 4 and the second inner surface 6. Thus, the density of this structural element can be significantly reduced. In addition, the arrangement of the cavities inside the structural layered element can be precisely adjusted, and the dimensional accuracy of the distance between the first inner surface 4 and the second inner surface 6 can be increased.

The first outer layer 1 includes the first outer surface C and the first inner surface 4. Similarly, the second outer layer 2 includes the second outer surface 5 and the second inner surface 6. The first inner surface 4 and the second inner surface b can be located at a distance from each other. one approximately from 20 to 250 mm. As a minimum, the first and second outer layers have a thickness of 2 mm and an intermediate layer of 20 mm. Preferably, the intermediate layer has a modulus of elasticity E of at least 250MPa, more preferably 275MPa, at the maximum anticipated ambient temperature in which the element is to be used. In shipbuilding, it can be 100"C. The elastomeric material should not be stiff enough, so E should be less than 5000MPa at the lowest temperatures, for example -40 or -457C in shipbuilding.

If additional shear stiffness or flexural stiffness is required for a particular application, metal plates or; Sections of graded rolled steel can be cast together or connected either to the profile or to the elastomer. Location, size, and quantity are selected based on load and design requirements. Plates or sections of graded rolled products can be located in the longitudinal direction, in the transverse direction, or in both directions.

The tensile, compressive, and tensile strengths and elongation of the elastomer must be maximized to allow the component layer material to absorb energy under extraordinary loads such as impact. In particular, the compressive and tensile strength of the elastomer should be at least 2, and preferably 20 MPa, and even better, 40 MPa. The compressive and tensile strength can, of course, significantly exceed these values.

Figure 5 shows a further example of the implementation of the present invention, in which plate keys 60 pass between the first and second outer layers 1 and 2. The plate keys 60 can be solid, or have punched holes 61, as shown in Figure 5, to allow passage to the injection molded interlayer 20, and after curing to increase the mechanical connection between the interlayer 20 and the plate keys 60. The punched plate keys provide stiffer elements that have less flexibility and weight. It is better when the plate keys 60 are located near the subsections 11, as shown in Fig.5. These sub-sections preferably extend substantially the entire length of the element so that the intermediate layer forms a plurality of spaced elongated ribs and the plate keys 60 are connected to one of these elongated ribs. The displacement is transmitted to the plate keys 60 through the connection (adhesive and mechanical coupling) to ensure the necessary bending stiffness.

Metal layers 1, 2 are preferably made of structural steel, although they can be made of aluminum, stainless steel or other structural alloys in special applications where lightness, corrosion resistance, inertness and . other special properties are essential. The metal should preferably have a minimum yield strength of 240 MPa and an elongation of at least 2095. In many applications, especially shipbuilding, it is important that the metal be weldable.

Metal layers 1, 2 can be made of any metals that provide any functions.

Examples are mild steel for low cost strength, stainless steel for strength and chemical resistance, and aluminum for light weight, good stiffness and strength.

The plasticity of the elastomer at the lowest operating temperatures must exceed the plasticity of the metal layers, which is approximately 2095. The best value for the plasticity of the elastomer at the lowest operating temperatures is 5095. The temperature coefficient of the elastomer must be close enough to the temperature coefficient of the steel so that temperature changes in the intended operating range and during welding do not create restrictions. The degree to which the temperature coefficients of the two materials can differ depends in part on the elasticity of the elastomer, but it is believed that the coefficient of thermal expansion of the elastomer can be about 10 times greater than the coefficient of thermal expansion of the metal layers. The coefficient of thermal expansion can be adjusted by adding fillers to the elastomer.

The bond strength between the elastomer and the metal layers should be at least 1 MPa, preferably 6 MPa over the entire operating temperature range. This is best achieved by the inherent adhesion of the elastomer to the steel, but additional bonding agents may be provided.

If the element is to be used in shipbuilding, additional requirements include that the tensile strength of the contact surfaces is sufficient to withstand the negative hydrostatic pressure and peeling forces from the steel joints. The profile and elastomer must be hydrolytically resistant to both sea and fresh water, and if the element is to be used in an oil tanker, it must be chemically resistant to oil.

Therefore, an elastomer essentially contains a polyol (ie, a complex polyester or a simple polyester) along with an isocyanate or diisocyanate, chain extenders, and fillers. Fillers are introduced as necessary to reduce the temperature coefficient of the intermediate layer, reduce its cost and regulate the physical properties of the elastomer by other means. Other additives, i.e. to control hydrophobic properties or tackiness, as well as flame inhibitors, may also be provided.

The profile 10 and the intermediate layer can be exposed (open) or hidden in the shell. When the profile 10 and the interlayer 20 are exposed, and when welding is minimal, if not absent, the interlayer material must provide the additional necessary shear strain between the plates and must be resistant to the environment (resistant to ultraviolet radiation, UV). Additional additives may be required for exposed materials to increase flame resistance.

The ratio of the total thickness of the outer layers to the thickness of the elastomer (T!-13)/1?7, as a rule, is in the range from 0.1 to 2.5. Elastomer is best when it is dense, that is, the air that gets into it is about less than 25 by volume of 905.

Coatings, which are applied for cosmetic reasons or for corrosion resistance, can be applied to the outer surfaces of the metal layers either before or after the production of the layer material (plastic).

Other coatings can also be created to protect the exposed elastomer.

The element according to the invention is essentially stronger and stiffer than an element of the same overall metal thickness that does not have an intermediate layer. This is because the element acts similarly to a box beam or I-beam, with the intermediate layer acting as the wall(s) of the beam. For such functioning, the intermediate layer itself and the connection with the outer walls must be strong enough to transfer the forces that arise when the element is used.

Another advantage of this invention, particularly in shipbuilding and bridge construction, is that the intermediate layer works to prevent the expansion of cracks between the inner and outer layers. The elasticity of the intermediate layer helps to prevent the expansion or growth of significant cracks. The component composite layer-by-layer material bends to a large radius at the support points or along the edges of the loads, dispersing the load during bending, reducing the corresponding stress concentrations and the possibility of the formation of fatigue cracks.

The best method of manufacturing a layer-by-layer element according to the invention consists in placing two metal layers 1,2 at a distance from each other, while between the two layers 1,2 in contact with the two layers 1,2 there is a profile 10. Thus, the distribution of the two layers is determined profile size 10.

The elastomer of the intermediate layer 20 is poured or injected (usually under pressure) directly into the last part of the cavity formed by the two metal layers 1 and 2, which is not occupied by the profile 10. The profile can be bonded to the steel plates by means of binders that have connections compatible with elastomeric materials, with the bond having sufficient strength to hold the plates in place during the injection process, until the elastomer has reached a sufficient degree of hardening.

When pouring, the plates 1, 2 can be held in an inclined position to facilitate the flow of the elastomer, or even vertically, although the hydrostatic pressure of the elastomer during pouring should not be strong, and the jet of displaced air should be optimized. The plates can also be fixed in place in the structure and filled with elastomer in place (on the construction site).

To allow the member to be welded to other members or to an existing structure, sufficient weld allowance must be left around the edges so that the elastomer and its bond to the steel plate are not damaged by the welding temperature. The width of the welding tolerance will depend on the heat resistance of the elastomer and the welding technology used, but it can be approximately 75 mm. If the elastomer is poured between the plates, the welding tolerance should be formed by elongated removable or cast-together spacers.

The number of channels required for injection and ventilation channels depends on the equipment for injecting elastomer components, which is available, to ensure minimal spattering (ideally - no spattering), as well as on the volume, direction and shape of the filling, the optimal number of removal points air (guarantee of the absence of air bubbles) and the time of elastomer thickening. Injection channels and ventilation channels should be located in the right places, depending on the purpose for which the element is intended. If the element is intended for use as a hot-rolled steel plate in a double-hull vessel, the injection channels are likely to face the inter-hull space rather than the sea or cargo space. The injection channels are easily disconnected, possibly with the help of one-way valves, which can be ground after filling. Channels for injection and ventilation can be simple holes drilled in metal face plates. In addition, they can be hermetically closed with metal caps made flush with the metal face plate. Plugs that are inserted into the injection and ventilation holes must be made of a material that has galvanic properties compatible with the metal layers.

The injection process must be promptly controlled to ensure uniform filling of the cavity without the effect of back pressure, which can lead to swelling and uneven thickness of the slab. Injection can also be performed using tubes that are removed as the cavity fills.

After manufacture and during the service life of the layer material, it may be necessary to ensure that the elastomer has the necessary adhesion to the metal layers. This can be done using ultrasound or gamma ray technology.

In order to repair damaged elements, or in the event that the elastomer does not have the required adhesion, the damaged area of the metal plate is cut out with a cold or fire sharp, and the elastomer is subjected to surface cutting, for example, with a milling hand machine, or hydraulic cleaning (water under pressure) , until a good quality elastomer is obtained and a weld tolerance is formed. The exposed surface of the last elastomer must be clean enough to bond with the new elastomer that is cast in place.

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Claims (34)

1. A plate made of structural layer-by-layer material, which contains: a first metal layer having a first inner surface and a first outer surface; a second metal layer having a second inner surface and a second outer surface, the second metal layer being spaced from said first metal layer; an intermediate layer consisting of an elastomer and bonded to said first and second inner surfaces, characterized in that a profile is located between said first and second inner surfaces, and said intermediate layer is located in a space between said first and second inner surfaces not occupied by it profile 2. A plate made of structural layer-by-layer material according to claim 1, which is characterized by the fact that the first and second metal layers are connected together by an intermediate layer of elastomer without welding the intermediate metal plates. 3. A plate made of structural layer material according to claims 1 or 2, which is characterized by the fact that the mentioned profile is made of multiple subsections. 4. A plate made of structural layer material according to claim 3, which is characterized by the fact that the mentioned subsections have an elongated shape. 5. A plate made of structural layered material according to paragraphs With or 4, which differs in that the mentioned set of subsections are interconnected by elements of interconnection. 6. A structural laminate board according to any one of claims 3, 4 or 5, wherein said sub-sections have mounting wells extending from surfaces of the sub-sections for contact with said first and second inner surfaces. 7. A plate made of structural layered material according to any of claims 3-6, which is characterized by the fact that said subsections are hollow. 8. A plate made of structural layered material according to any of claims 3-7, characterized in that not all sub-sections of the profile have the same shape. 9. A plate made of structural layered material according to any of claims 3-8, which is characterized by the fact that not all sub-sections of the profile are located at the same distance. 10. A plate made of structural layered material according to any of claims 4-9, which is characterized by the fact that the cross-sectional area of the mentioned subsections exceeds the cross-sectional area of the mentioned interconnection elements. 11. A plate of structural layered material according to any of the previous items, characterized in that a plurality of profiles runs substantially along the entire length of said element such that said intermediate layer forms a plurality of elongated ribs spaced from each other . 12. A plate of structural layered material according to any of the preceding items, characterized in that it further comprises at least one plate key, substantially perpendicular to and located between said first and second layers, and connected to said intermediate layer . 13. A plate of structural layered material according to claim 12, characterized in that said at least one plate key has a through hole. 14. A plate made of structural layered material according to any of the previous items, which differs in that said profile is made of foam, preferably polyurethane foam (PU). 15. A plate made of structural layered material according to any of claims 1-14, which is characterized by the fact that said profile is made of polypropylene. 16. A plate of structural layered material according to any of the previous items, characterized in that said profile is located in partial contact with at least one of said first and second metal layers. 17. A slab of structural layered material according to any of the preceding claims, characterized in that it has continuous paths extending from the first inner layer to the second inner layer and bypassing said profile. 18. A slab of structural layer-by-layer material according to any of the preceding items, characterized in that it has straight paths that pass from the first inner layer to the second inner layer and bypass said profile, and said straight paths are substantially perpendicular to said profile first and second metal layers. 19. A plate of structural layered material according to any of the previous items, characterized in that additional metal elements are located between said first and second surfaces, which bear the load, but are not welded to them. 20. A plate of structural layered material according to claim 19, characterized in that said elastomer is bonded to said additional elements. 21. A plate of structural layered material according to any of the preceding items, characterized in that said elastomer has a modulus of elasticity E greater than or equal to approximately 250 MPa, and plasticity exceeding that of metal layers. 22. A plate of structural layered material according to claim 21, characterized in that said elastomer has a modulus of elasticity greater than or equal to about 275 MPa. 23. A plate of structural layered material according to any of the previous items, characterized in that said elastomer has a tensile and compressive strength of at least 2 MPa. 24. A plate of structural layered material according to any of the previous items, characterized in that said elastomer has an adhesion strength to said metal layers of at least 1 MPa. 25. A plate of structural layered material according to any of the previous items, characterized in that said elastomer is dense. 26. A plate of structural layered material according to any of the previous items, characterized in that said first and second metal layers are spaced from each other by about 20 to 250 mm. 27. A plate of structural layered material according to any of the preceding claims, characterized in that each of said first and second metal layers has a thickness in the range of about 2.0 to 25 mm. 28. A plate made of structural layered material according to any of the previous items, which is characterized in that the ratio of the total thickness of the first and second metal layers to the thickness of the intermediate layer is in the range from 0.1 to 2.5. 29. A method of manufacturing a plate from structural layered material, which includes: placing the first and second layers at a distance from each other to form a cavity; pouring an uncured elastomer into said cavity and curing said elastomer in such a way as to ensure its adhesion to said metal layers, characterized in that before the stage of pouring the profile is placed in the cavity in partial contact with both metal layers so that it partially fills said cavity. 30. The method according to claim 29, which is characterized by the fact that between the mentioned first and second internal surfaces, but not in contact with them, additional metal elements are placed that carry the load. 31. The method according to claims 29 or 30, which differs in that the mentioned profile is made of foam, preferably polyurethane foam (PU). 32. The method according to claims 29, 30 or 31, which is characterized in that the additional mechanical elements that carry the load are cast integrally with said profile. 33. The method according to claims 29, 30, 31 or 32, which is characterized in that the additional mechanical elements that carry the load are cast integrally with said elastomer. 34. The method according to any one of claims 29 - 33, which is characterized in that the elastomer after curing has a modulus of elasticity E greater than or equal to approximately 250 MPa, and a plasticity that exceeds the plasticity of the metal layers.