Composite material structure

Abstract

The present application provides a kind of composite structure. The composite structure includes composite laminate structure and core material assembly;Two composite laminate structures are included in the composite laminate structure, and the core material assembly is located between the two composite laminate structures. The core material assembly includes a first core portion and a second core portion. The distance between the first core portion and the load is less than the distance between the second core portion and the load. The density of the first core portion is greater than the density of the second core portion, which can make the structure lightweight.

Description

Technical Field

[0001] This invention relates to composite material sandwich structures, and more particularly to a composite material structure. Background Technology

[0002] The nacelle system is a crucial component of civil aircraft engines, serving functions such as sound insulation, anti-icing, reducing aerodynamic noise, and providing thrust reverser. During engine operation, the nacelle must withstand aerodynamic loads, and significant loads are often transmitted at critical connection points, such as the main slide rail connection area. Weight is a key indicator of the economic efficiency of civil aircraft engines, necessitating a lightweight design for the nacelle.

[0003] In the thrust reverser, the movable outer casing and fixed structure are connected by six structural points: the main slide rail and the slide groove, the auxiliary slide rail and the slide groove, and the actuator cylinder joint and the outer wall of the culvert. Under most operating conditions, the main slide rail and the slide groove bear the function of transmitting loads, thus posing a significant challenge to the installation structure of the main slide rail.

[0004] However, taking the connection of the main slide rail to the outer wall of the culvert as an example, one existing technology is to install the main slide rail on a sandwich structure. Due to the thickness requirements of the core material, this structure requires a larger installation space, and a sandwich structure cannot be used when the space height is insufficient. Another existing technology is to install it on a composite laminate, but the increased thickness of the composite laminate leads to an increase in overall weight. Summary of the Invention

[0005] The purpose of this invention is to provide a composite material structure that can make the structure lightweight.

[0006] One aspect of the present invention provides a composite material structure, including a composite laminate structure and a core material assembly; there are two composite laminate structures, and the core material assembly is located between the two composite laminate structures; the core material assembly includes a first core portion and a second core portion; the distance between the first core portion and the composite material structure subjected to a load is less than the distance between the second core portion and the load, and the density of the first core portion is greater than the density of the second core portion.

[0007] In one embodiment, the first core portion is a first core material, and the second core portion includes a second core material and a third core material; the density of the second core material is less than the density of the first core material, and the density of the third core material is less than the density of the first core material.

[0008] In one embodiment, the core material parameters of the first core material, the second core material, and the third core material are determined according to the load on the composite material structure; wherein, the core material parameters include core material type, core material width, and direction of maximum shear force.

[0009] In one embodiment, the first core material is an acoustic honeycomb core, a non-acoustic honeycomb core, or foam; and / or the second core material is an acoustic honeycomb core, a non-acoustic honeycomb core, or foam; and / or the third core material is an acoustic honeycomb core, a non-acoustic honeycomb core, or foam.

[0010] In one embodiment, the first core material, the second core material, and the third core material are cured by adhesive bonding.

[0011] In one embodiment, the composite laminate structure includes a first composite laminate, a second composite laminate, a third composite laminate, and a fourth composite laminate; wherein the first composite laminate and the third composite laminate are connected and connected to the core material assembly; the second composite laminate and the fourth composite laminate are connected and connected to the core material assembly; the distance between the first composite laminate and the load on the composite material structure is less than the distance between the third composite laminate and the load, and the number of layers in the first composite laminate is greater than the number of layers in the third composite laminate; the distance between the second composite laminate and the load is less than the distance between the fourth composite laminate and the load, and the number of layers in the second composite laminate is greater than the number of layers in the fourth composite laminate.

[0012] In one embodiment, the third composite laminate is located upstream of the fourth composite laminate in the direction of noise propagation, and the third composite laminate is a perforated plate.

[0013] In one embodiment, the first composite laminate and the third composite laminate have a layer drop transition; and / or the second composite laminate and the fourth composite laminate have a layer drop transition.

[0014] In one embodiment, the first composite laminate is an anisotropic material composed of multiple layers of fabric or unidirectional tape; and / or the second composite laminate is an anisotropic material composed of multiple layers of fabric or unidirectional tape; and / or the third composite laminate is an anisotropic material composed of multiple layers of fabric or unidirectional tape; and / or the fourth composite laminate is an anisotropic material composed of multiple layers of fabric or unidirectional tape.

[0015] The composite material structure of this invention divides the core assembly into a first core portion and a second core portion according to the load location. A higher-density core material is used in areas with high load to improve structural strength; a lower-density core material is used in areas with low load to reduce weight. Using composite materials throughout, with different densities in different areas, ensures a low overall structural weight, meeting the requirements of lightweight yet high strength. Attached Figure Description

[0016] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0017] Figure 1 This is a schematic diagram of an embodiment of a composite material structure according to the present invention;

[0018] Figure 2 yes Figure 1 A schematic diagram showing the overlapping arrangement of the composite material laminates in the composite material structure;

[0019] Figure 3 yes Figure 1 A schematic diagram showing the number of layers at different locations in each composite laminate structure;

[0020] Figure 4 This is a flowchart illustrating the design method for composite material structures according to the present invention;

[0021] Figure 5 This is a schematic diagram of the composite material structure of the present invention applied to a thrust reverser device;

[0022] Figure 6 This is a schematic flowchart of the manufacturing method of the composite material structure of the present invention;

[0023] Figure 7 This is a schematic diagram of the experimental verification process for the composite material structure of the present invention;

[0024] Figure 8 This is a schematic diagram of the axial, bending, and shear test flow of the composite material structure of the present invention. Detailed Implementation

[0025] In the aviation field, weight is a crucial performance indicator. For civil aviation, weight directly impacts fuel consumption, affecting economic efficiency and making it a highly sensitive parameter. Therefore, with the development of aviation technology, the application of composite materials in aerospace structures is increasing. Composite materials possess characteristics such as anisotropy, high designability, and high specific strength. However, they also bring some challenges, such as demanding space requirements, complex manufacturing processes, and significant design difficulties. Designing a structural solution that is the lightest, strongest, and quietest within the smallest possible space and under the greatest load presents a significant challenge.

[0026] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the invention and not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the invention without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0027] As used herein, the terms “first,” “second,” “third,” and “fourth” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of the individual components.

[0028] The composite material structure of the present invention includes a composite laminate structure and a core material assembly. Two composite laminate structures are present, with the core material assembly located between the two composite laminate structures to form a sandwich structure. The core material assembly includes a first core portion and a second core portion. The distance between the first core portion and the composite material structure subjected to a load is less than the distance between the second core portion and the load; that is, the first core portion is closer to the load than the second core portion. The density of the first core portion is greater than the density of the second core portion.

[0029] The composite material structure of this invention divides the core assembly into a first core portion and a second core portion according to the load location. A higher-density core material is used in areas with high load to improve structural strength; a lower-density core material is used in areas with low load to reduce weight. Using composite materials throughout, with different densities in different areas, ensures a low overall structural weight, meeting the requirements of lightweight yet high strength.

[0030] Since aircraft structures have limited space and many large load areas, this invention is applied to ensure that large load areas meet strength design requirements within a limited structural space.

[0031] The composite material structure of the present invention is not limited to the moving structure of the nacelle thrust reverser, but can also be used in other structural areas with requirements such as lightweight, high strength, and low noise.

[0032] Figure 1An embodiment of the composite material structure of the present invention is shown. In one embodiment, the first core portion is a first core material 3, and the second core portion includes a second core material 6 and a third core material 7. The density of the second core material 6 is less than the density of the first core material 3, and the density of the third core material 7 is less than the density of the first core material 3. In the composite material structure of the present invention, the first core material 3 is defined as the position closest to the load, thus having the highest density and best mechanical properties to meet the strength design requirements.

[0033] The core material parameters of the first core material 3, the second core material 6, and the third core material 7 are determined based on the loads applied to the composite material structure. These core material parameters include the core material type, core material width, and the direction of the maximum shear force. The location and magnitude of the load both influence the selection of the core material parameters for each core material.

[0034] For example, such as Figure 1 As shown, the load on the composite material structure is located at Figure 1 On the left side, closer to the first core portion, the density of the first core material 3 is greater than that of the second core material 6 and the third core material 7. Since the second core material 6 and the third core material 7 are farther from the load, they experience less load or impact, and therefore their width can be smaller than that of the first core material 3. The direction of the maximum shear force of the second core material 6 and the third core material 7 can be determined according to actual conditions to improve the mechanical properties of the core material assembly.

[0035] The first core material 3, the second core material 6, and the third core material 7 are all anisotropic materials with mechanical properties such as resistance to compression, tension, and shear, and the direction of their maximum shear strength is consistent with the direction of the maximum shear force.

[0036] The nacelle is a key component for engine noise reduction; therefore, its design must consider low noise requirements. Thus, under noise-considered operating conditions, the first core material 3 and / or the second core material 6 and / or the third core material 7 are used as noise-reducing materials. The noise-reducing material can be an acoustic honeycomb. Therefore, the materials for the first core material 3, the second core material 6, and the third core material 7 include, but are not limited to, acoustic honeycomb cores, foam, and non-acoustic honeycomb cores.

[0037] In such Figure 1 In the illustrated embodiment, from left to right, the components are a first core material 3, a second core material 6, and a third core material 7. The first core material 3, the second core material 6, and the third core material 7 are cured by adhesive bonding. Figure 1 Taking the structure shown as an example, the first core material 3 and the second core material 6 are cured by adhesive bonding, and the second core material 6 and the third core material 7 are cured by adhesive bonding to obtain a core material assembly.

[0038] like Figure 1As shown, in one embodiment, the composite laminate structure includes a first composite laminate 1, a second composite laminate 2, a third composite laminate 4, and a fourth composite laminate 5. The first composite laminate 1 and the third composite laminate 4 are connected and connected to the core material assembly. The second composite laminate 2 and the fourth composite laminate 5 are connected and connected to the core material assembly. The third composite laminate 4 and the fourth composite laminate 5 are composite laminates connected to the core material assembly.

[0039] The distance between the first composite laminate 1 and the load on the composite material structure is less than the distance between the third composite laminate 4 and the load, and the number of layers in the first composite laminate 1 is greater than the number of layers in the third composite laminate 4. The distance between the second composite laminate 2 and the load is less than the distance between the fourth composite laminate 5 and the load, and the number of layers in the second composite laminate 2 is greater than the number of layers in the fourth composite laminate 5. That is to say, in the composite material structure of the present invention, the first composite laminate 1 and the second composite laminate 2 are positioned closer to the load composite laminate than the second composite laminate 2 and the fourth composite laminate 5.

[0040] This invention employs various types of composite laminates, using thicker laminates in areas with high loads to improve structural strength, and thinner laminates in areas with low loads to reduce weight.

[0041] In one embodiment, considering noise conditions, the third composite laminate 4 is located upstream of the fourth composite laminate 5 in the noise propagation direction, and the third composite laminate 4 is a perforated plate. That is, in the composite material structure of the present invention, the third composite laminate 4 is defined as a composite laminate upstream of the fourth composite laminate 5 in the noise propagation direction. In this case, the third composite laminate 4 is a perforated plate.

[0042] like Figure 1 In the embodiment shown, the noise propagation direction is from top to bottom.

[0043] It is important to note that only one of the third composite laminate 4 and the fourth composite laminate 5 is a perforated board. If both are perforated boards, sound will directly penetrate the composite material structure, thus failing to achieve the purpose of noise reduction.

[0044] Since the first composite laminate 1 and the second composite laminate 2 are close to the load, using perforated plates would reduce the load-bearing capacity. Therefore, the first composite laminate 1 and the second composite laminate 2 need to be non-perforated plates.

[0045] By combining the above embodiments of various core materials, and by using core materials with various mechanical properties, and using higher density core materials and thicker non-perforated plates in areas with high loads, while using acoustic honeycomb materials as core materials and perforated plates in other areas, the composite material structure has a noise reduction function.

[0046] The area where perforated panels can be laid (the third composite laminate 4 and the fourth composite laminate 5) can be larger, ensuring better noise reduction performance.

[0047] The first composite laminate 1, the second composite laminate 2, the third composite laminate 4, and the fourth composite laminate 5 can be selected as anisotropic materials composed of multiple layers of fabric or unidirectional tape. The number of layers and the angles of the four can be selected according to the actual situation.

[0048] For example, such as Figure 2 As shown, the composite laminates in this invention are formed by overlapping fabrics or unidirectional tapes (simplified as lay-ups) with anisotropic mechanical properties at a certain angle. Figure 2 The composite laminate shown has a total of 4 layers.

[0049] like Figure 3 As shown, laminates can use different amounts of fabric or unidirectional tape in different locations. In the schematic diagram, the left side (thin area) has 4 layers, and the right side (thick area) has 7 layers of fabric or unidirectional tape. The thickness variation area is called the delamination zone, with a delamination transition between the left and right sides.

[0050] Combination Figure 1 and Figure 3 The first composite laminate 1 and the third composite laminate 4 undergo a layer-drop transition. The second composite laminate 2 and the fourth composite laminate 5 also undergo a layer-drop transition. Layer-drop transitions are a connection method that gradually reduces the number of layers when the number of layers in the two composite laminates is inconsistent. This can improve the overall structural integrity and reliability, and alleviate stress concentration.

[0051] like Figure 1 As shown, the first core material 3 has a sloped closed edge, which facilitates the transition between the first composite laminate 1 and the third composite laminate 4, as well as between the second composite laminate 2 and the fourth composite laminate 5. The angle of the closed edge of the first core material 3 should be as small as possible to improve the bonding degree of each composite laminate, reduce manufacturing difficulty, and prevent structural cracking.

[0052] In conjunction with the above embodiments, Figure 4 The design method of the composite material structure of the present invention is illustrated. The non-core region is... Figure 1 The sandwich area contains areas without core material, while the core area contains core material (i.e., the first core material 3, the second core material 6, and the third core material 7). The noise reduction element is either the third composite laminate 4 or the fourth composite laminate 5. The "design requirements" in the "Does it meet the design requirements?" step refer to strength design requirements, which can be determined through simulation analysis. If the design requirements are not met, the design must be re-executed to determine the actual number of layers and obtain the stress-strain level of the structure. If the design requirements are met, verification can be achieved through testing.

[0053] like Figure 4 As shown, the width of the sandwich area and the non-sandwich area can be determined according to the location and magnitude of the load. The location of the noise reduction element can be determined according to the direction of noise propagation. The number of layers in each composite laminate can be determined according to the magnitude of the load, and the layup angle can be determined according to the load material laying standard. The core material parameters of each core material can be determined according to the location of the load (load transfer sequence) and the magnitude of the load.

[0054] The composite material structure of the present invention can be designed to achieve different configurations of honeycomb sandwich structures by adjusting the number of layers, layup direction, and honeycomb material properties of the composite laminate for different usage environments.

[0055] For example, such as Figure 5 The structure shown includes a fan shroud 102 and an air intake duct 101. The fan shroud 102 has an arc-shaped structure. The composite material structure of this invention can be applied to applications such as... Figure 5 The fan cover 102 shown, as well as other shapes and... Figure 5 The fan cover 102 shown has a similar arc-shaped structure.

[0056] refer to Figure 5 Area A and Area C are composed of a first composite laminate 1 and a second composite laminate 2, while Area B is composed of a first core material 3, a third composite laminate 4, a fourth composite laminate 5, a second core material 6, and a third core material 7.

[0057] Areas A and C are connected to other structures, and loads are transferred through these connections. The widths of areas A and C are determined by the dimensions of the relevant connecting structures. Based on structural design considerations, the thicknesses (i.e., the number of layers) of the first composite laminate 1, second composite laminate 2, third composite laminate 4, and fourth composite laminate 5, as well as the densities, heights, and widths of the first core material 3, second core material 6, and third core material 7, are designed. Finite element analysis is performed to obtain the mechanical strength margins of each component. If the margin is less than 0, the number of layers needs to be increased; if the margin is greater than 0, the number of layers can be reduced or a lower-density core material can be used to achieve weight reduction.

[0058] If noise reduction is needed, holes can be drilled in area B on the composite laminate facing the sound source. The perforated laminate is also called a perforated board, and a honeycomb with noise reduction function, also known as a sound-lined honeycomb, can be used to achieve the purpose of noise reduction.

[0059] according to Figure 1 The illustrated embodiments, such as Figure 6 As shown, the following is a method for manufacturing the composite material structure of the present invention:

[0060] First, the first core material 3 and the second core material 6 are cured by adhesive bonding, and the second core material 6 and the third core material 7 are cured by adhesive bonding to obtain a core material assembly.

[0061] The core material assembly and the second and fourth composite laminates 5 are prepared by adhesive bonding to obtain a sandwich structure semi-finished product.

[0062] Finally, the sandwich structure semi-finished product is bonded and cured with the first composite laminate 1 and the third composite laminate 4 to obtain the finished sandwich structure.

[0063] The composite material structure of the present invention can be manufactured by using a variety of core materials and a variety of laminate bonding and curing methods.

[0064] Composite material structures that meet design requirements can have their strength verified through testing. Tests include axial tension / compression tests, in-plane shear tests, upper / lower bending tests, and axial + bending + shear tests.

[0065] The composite material structure test specimens were obtained by processing the above design and manufacturing methods, and impact damage was introduced for experimental verification.

[0066] like Figure 7 As shown, the axial tensile / compression test procedure is as follows:

[0067] 1) The test specimen is subjected to axial tension, and the load is gradually increased to the limit load, and then unloaded;

[0068] 2) Axially compress the test specimen, gradually increasing the load to the limit load, and then unload it;

[0069] 3) Perform a C-scan on the test specimen to check for damage. If damage is found, the test fails and the test specimen needs to be redesigned. If there is no damage, proceed to the next step.

[0070] 4) The test specimen is subjected to axial tension, and the load is gradually increased to the ultimate load, and then unloaded;

[0071] 5) Axially compress the test specimen, gradually increasing the load to the ultimate load, and then unload it;

[0072] 6) Perform a C-scan on the test specimen to check for damage. If damage is found, the test fails and the test specimen needs to be redesigned.

[0073] like Figure 7 As shown, the in-plane shear test process is as follows:

[0074] 1) Perform an in-plane shear test on the test specimen, gradually increasing the load to the limit load, and then unloading;

[0075] 2) Perform a C-scan on the test specimen to check for damage. If damage is found, the test fails and the test specimen needs to be redesigned. If not, proceed to the next step.

[0076] 3) Perform an in-plane shear test on the test specimen, gradually increasing the load to the ultimate load, and then unloading;

[0077] 4) Perform a C-scan on the test specimen to check for damage. If damage is found, the test fails and the test specimen needs to be redesigned.

[0078] like Figure 7 As shown, the upper / lower bending test process is as follows:

[0079] 1) Perform an upward bending test on the test specimen, gradually increasing the load to the limit load, and then unloading;

[0080] 2) Perform a downward bending test on the test specimen, gradually increasing the load to the limit load, and then unloading;

[0081] 3) Perform a C-scan on the test specimen to check for damage. If damage is found, the test fails and the test specimen needs to be redesigned. If there is no damage, proceed to the next step.

[0082] 4) Perform an upward bending test on the test specimen, gradually increasing the load to the ultimate load, and then unloading;

[0083] 5) Perform a downward bending test on the test specimen, gradually increasing the load to the ultimate load, and then unloading;

[0084] 6) Perform a C-scan on the test specimen to check for damage. If damage is found, the test fails and the test specimen needs to be redesigned.

[0085] like Figure 8 As shown, the procedure for the axial + bending + shear test is similar to the three tests mentioned above. The actual load on the designed component is generally a coupling of axial load, bending load, and shear load. After obtaining the actual load, it is applied to the test piece to assess whether the test piece can meet the strength design requirements under the actual load.

[0086] If the test specimens are not damaged in the above test items, then the test specimens meet the strength test requirements, that is, the composite material structure under these parameter conditions meets the strength design requirements.

[0087] The strength performance of the designed composite material structure is verified by the above-mentioned practical test methods to ensure that the structure meets the strength design requirements.

[0088] The composite material structure of this invention reduces structural mass while maintaining structural strength by using different core materials and laminates of different thicknesses in different regions. Simultaneously, through structural design, more loads are borne by smaller areas, increasing the area of ​​the perforated plate and achieving noise reduction, thus meeting the requirements of lightweight, high-strength, and low-noise composite material structures.

[0089] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A composite material structure, characterized in that, Including composite laminate structures and core material assemblies; The composite laminate structure consists of two parts, and the core material assembly is located between the two composite laminate structures. The core material assembly includes a first core portion and a second core portion; The distance between the load on the first core portion and the composite material structure is less than the distance between the second core portion and the load, and the density of the first core portion is greater than the density of the second core portion.

2. The composite material structure as described in claim 1, characterized in that, The first core portion is a first core material, and the second core portion includes a second core material and a third core material; The density of the second core material is less than the density of the first core material, and the density of the third core material is less than the density of the first core material.

3. The composite material structure as described in claim 2, characterized in that, The core material parameters of the first core material, the second core material, and the third core material are determined based on the loads applied to the composite material structure; wherein, The core material parameters include core material type, core material width, and direction of maximum shear force.

4. The composite material structure as described in claim 3, characterized in that, The first core material is an acoustic honeycomb core, a non-acoustic honeycomb core, or foam; and / or The second core material is an acoustic honeycomb core, a non-acoustic honeycomb core, or foam; and / or The third core material is an acoustic honeycomb core, a non-acoustic honeycomb core, or foam.

5. The composite material structure according to any one of claims 1 to 4, characterized in that, The first core material, the second core material, and the third core material are cured by adhesive bonding.

6. The composite material structure according to any one of claims 1 to 4, characterized in that, The composite laminate structure includes a first composite laminate, a second composite laminate, a third composite laminate, and a fourth composite laminate; wherein... The first composite laminate and the third composite laminate are connected, and are also connected to the core material assembly; The second composite laminate and the fourth composite laminate are connected, and are also connected to the core material assembly; The distance between the load on the first composite laminate and the composite material structure is less than the distance between the load on the third composite laminate, and the number of layers in the first composite laminate is greater than the number of layers in the third composite laminate. The distance between the second composite laminate and the load is less than the distance between the fourth composite laminate and the load, and the number of layers in the second composite laminate is greater than the number of layers in the fourth composite laminate.

7. The composite material structure as described in claim 6, characterized in that, The third composite laminate is located upstream of the fourth composite laminate in the direction of noise propagation, and the third composite laminate is a perforated board.

8. The composite material structure as described in claim 6, characterized in that, The first composite laminate and the third composite laminate have a delamination transition; and / or The second composite laminate and the fourth composite laminate have a layer transition.

9. The composite material structure as described in claim 6, characterized in that, The first composite laminate is an anisotropic material composed of multiple layers of fabric or unidirectional tape; and / or The second composite laminate is an anisotropic material composed of multiple layers of fabric or unidirectional tape; and / or The third composite laminate is an anisotropic material composed of multiple layers of fabric or unidirectional tape; and / or The fourth composite laminate is an anisotropic material composed of multiple layers of fabric or unidirectional tape.

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