Method for measuring compression amount of honeycomb core before and after curing

Abstract

The invention relates to the technical field of interlayer composite material manufacturing, and particularly discloses a method for measuring the compression amount of a honeycomb core before and after curing, which comprises the following steps: selecting the type and thickness of the honeycomb core; an upper flexible metal sheet, an upper adhesive film, a honeycomb core, a lower adhesive film and a lower flexible metal sheet are sequentially laid on a flat plate tool to form an interlayer assembly, the thickness H1 of the interlayer assembly before curing is measured, then a protection assembly is arranged on the periphery of the interlayer assembly in a surrounding mode to form a to-be-cured workpiece, the to-be-cured workpiece is cured, and the to-be-cured workpiece is obtained. And then measuring the thickness H2 of the interlayer assembly after curing, and finally calculating the compression amount S of the interlayer assembly before and after curing, S = H1-H2. According to the method, the upper flexible metal thin plate and the lower flexible metal thin plate are used, the deformation generated by the cured honeycomb core can be effectively fit, the thickness of the upper flexible metal thin plate and the thickness of the lower flexible metal thin plate are not changed before and after curing, and the measurement accuracy is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sandwich composite material manufacturing, and particularly relates to a method for measuring compression amount of honeycomb core before and after curing. BACKGROUND

[0002] At present, sandwich composite materials are widely used in the field of aerospace due to their superior performance, wherein the sandwich composite material is usually composed of an upper panel, a honeycomb core, a film and a lower panel. In the process of aircraft design, due to the requirements of function, cost control and other needs, sandwich structure parts with different levels of honeycomb core splicing are needed, such as honeycomb and foam honeycomb core splicing, different density honeycomb splicing and the like. Due to the difference in mechanical properties of different types of honeycomb core, after the panel is laid and cured, the step difference will appear at the splicing position of the honeycomb core. The existing technology usually measures the step difference by laying the panel with multiple types of honeycomb core and curing, and measuring the thickness of the cured honeycomb core and panel to obtain the compression amount of the cured honeycomb core. However, the panel will shrink after curing, the surface will be uneven, and the thickness measurement will have a large error and a large data dispersion. SUMMARY

[0003] The present application aims to provide a method for measuring the compression amount of honeycomb core before and after curing, so as to solve the problem of inaccurate measurement of the compression amount of honeycomb core before and after curing in the prior art, and provide data support for the design and material selection of different core material splicing structures.

[0004] In order to solve the above problems, the present application provides a method for measuring the compression amount of honeycomb core before and after curing, which comprises:

[0005] S1: selecting the type and thickness of the honeycomb core;

[0006] S2: sequentially laying an upper flexible metal sheet, an upper film, the honeycomb core, a lower film and a lower flexible metal sheet to form a sandwich assembly, and measuring the thickness H1 of the sandwich assembly before curing;

[0007] S3: surrounding the sandwich assembly with a protection assembly to form a to-be-cured workpiece;

[0008] S4: curing the to-be-cured workpiece, and measuring the thickness H2 of the sandwich assembly after curing;

[0009] S5: calculating the compression amount S of the sandwich assembly before and after curing, S=H1-H2.

[0010] As an optional technical solution of the method for measuring the compression amount of honeycomb core before and after curing, the upper flexible metal sheet and the lower flexible metal sheet are both thin aluminum sheets or thin copper sheets.

[0011] As an optional technical solution of the method for measuring the compression amount of the honeycomb core before and after curing, the thickness of the upper flexible metal sheet and the lower flexible metal sheet is 1.5mm-2.5mm.

[0012] As an optional technical solution of the method for measuring the compression amount of the honeycomb core before and after curing, S2 further comprises:

[0013] According to the thickness of the upper adhesive film, it is selected whether to bond the upper side of the honeycomb core to the upper flexible metal sheet through the upper adhesive film or not; and / or,

[0014] According to the thickness of the lower adhesive film, it is selected whether to bond the lower side of the honeycomb core to the lower flexible metal sheet through the lower adhesive film or not.

[0015] As an optional technical solution of the method for measuring the compression amount of the honeycomb core before and after curing, the protection assembly comprises a protection baffle and a protection sheet, the protection baffle is arranged around the sandwich combination in the height direction of the sandwich combination, and the protection sheet is arranged on the upper end surface of the protection baffle and the upper flexible metal sheet.

[0016] After the protection baffle is arranged around the sandwich combination, a gap is reserved between the protection baffle and the honeycomb core.

[0017] As an optional technical solution of the method for measuring the compression amount of the honeycomb core before and after curing, the gap between the protection baffle and the honeycomb core is 1mm-2mm.

[0018] As an optional technical solution of the method for measuring the compression amount of the honeycomb core before and after curing, the material of the protection baffle is aluminum alloy or stainless steel, and the material of the protection sheet is glass fiber or carbon fiber.

[0019] As an optional technical solution of the method for measuring the compression amount of the honeycomb core before and after curing, S4 further comprises:

[0020] The to-be-cured workpiece is packaged;

[0021] The packaged to-be-cured workpiece is cured and formed according to the curing curve of the autoclave prepreg.

[0022] As an optional technical solution of the method for measuring the compression amount of the honeycomb core before and after curing, packaging the to-be-cured workpiece comprises:

[0023] The to-be-cured workpiece is packaged using a vacuum bag film, and the vacuum bag film is vacuumized.

[0024] As an optional technical solution of the method for measuring the compression amount of the honeycomb core before and after curing, S4 further comprises:

[0025] Dismantling the protective assembly of the to-be-solidified piece after curing, measuring the thickness H2 of the interlayer assembly after curing.

[0026] The present application has the following advantages:

[0027] The present application provides a method for measuring the compression amount of a honeycomb core before and after curing, which comprises the following steps: first, according to the type and thickness of the honeycomb core required by the experiment, then sequentially laying the flexible metal sheet, the upper adhesive film, the honeycomb core, the lower adhesive film and the lower flexible metal sheet on the flat plate tool to form an interlayer assembly, then measuring the thickness H1 of the interlayer assembly before curing, then surrounding the interlayer assembly with a protective assembly to form a to-be-solidified piece, then curing the to-be-solidified piece, then measuring the thickness H2 of the interlayer assembly after curing, and finally calculating the compression amount S of the interlayer assembly before and after curing, S=H1-H2. By using the above method, the upper flexible metal sheet and the lower flexible metal sheet are used, which can effectively fit the deformation amount of the cured honeycomb core, and the thickness of the upper flexible metal sheet and the lower flexible metal sheet does not change before and after curing, which effectively improves the accuracy of the measurement and effectively solves the problem of large measurement error caused by the uneven surface of the cured panel in the prior art. At the same time, the compression amount of the honeycomb core during the curing process can be simulated and calculated, the compression amount data obtained has small dispersion, and the problems of high cost and long cycle of the test of multiple honeycomb splicing combinations are avoided, so as to guide the design and material selection of different core material splicing structures. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The flow chart of the method for measuring the compression amount of a honeycomb core before and after curing in the embodiment of the present application;

[0029] Figure 2 The structure diagram of the interlayer assembly and the protective assembly after installation in the embodiment of the present application;

[0030] Figure 3 The cross-sectional view of the interlayer assembly and the protective assembly after installation in the embodiment of the present application;

[0031] Figure 4 The side view of the interlayer assembly in the embodiment of the present application.

[0032] In the drawings:

[0033] 1, honeycomb core;

[0034] 2, upper flexible metal sheet;

[0035] 3, upper adhesive film;

[0036] 4, lower adhesive film;

[0037] 5. Lower flexible metal sheet;

[0038] 6. Guard assembly; 61, guard bar; 62, guard flap;

[0039] 7. Sandwich assembly;

[0040] 8. Article to be cured. DETAILED DESCRIPTION

[0041] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0042] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and moreover, the "above", "over" and "on" of the first feature to the second feature include the first feature directly above and obliquely above the second feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The "below", "under" and "under" of the first feature to the second feature include the first feature directly below and obliquely below the second feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0043] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended only for explanation of the present application, and cannot be understood as limiting the present application.

[0045] As shown in the drawings, the present embodiment provides a method for measuring the compression amount of honeycomb core before and after curing, which comprises: S1: selecting the type and thickness of the honeycomb core 1; S2: sequentially laying the upper flexible metal sheet 2, the adhesive film 3, the honeycomb core 1, the lower adhesive film 4 and the lower flexible metal sheet 5 to form a sandwich assembly 7, and measuring the thickness H1 of the sandwich assembly 7 before curing; S3: using the protective assembly 6 to surround the four sides of the sandwich assembly 7 to form a curing product 8; S4: curing the curing product 8, and measuring the thickness H2 of the sandwich assembly 7 after curing; S5: calculating the compression amount S of the sandwich assembly 7 before and after curing, S = H1-H2. Figures 1 to 4 Using the above method, the upper flexible metal sheet 2 and the lower flexible metal sheet 5 are used, which can effectively fit the deformation amount of the cured honeycomb core 1, and the thickness of the upper flexible metal sheet 2 and the lower flexible metal sheet 5 does not change before and after curing, effectively improving the accuracy of the measurement, effectively solving the problem of uneven surface of the cured panel in the prior art, resulting in large measurement error; At the same time, it can also simulate the curing state of the prepreg and calculate the compression amount of the honeycomb core 1 during the curing process, and the compression amount data obtained has small dispersion, avoiding the problems of high test cost and long cycle of multiple honeycomb splicing combinations, so as to guide the design and material selection of different core material splicing structures.

[0046] It should be noted that different types of honeycomb cores can be cured separately or together, which is determined according to the size of the protective assembly 6 and the honeycomb core 1.

[0047] In the present embodiment, the upper flexible metal sheet 2 and the lower flexible metal sheet 5 each include but are not limited to thin aluminum sheet or thin copper sheet. Among them, the thin aluminum sheet and the thin copper sheet each have a certain flexibility, which can fit the deformation amount of the cured honeycomb core 1, and at the same time the thickness of the thin aluminum sheet or the thin copper sheet does not change after curing, thereby effectively ensuring the accuracy of the measurement.

[0048]

[0049] ​Further, the thickness of the upper flexible metal sheet 2 and the lower flexible metal sheet 5 is set to 1.5mm-2.5mm. By setting the thickness of the upper flexible metal sheet 2 and the lower flexible metal sheet 5 within the above range, the upper flexible metal sheet 2 and the lower flexible metal sheet 5 have certain flexibility and rigidity. The thickness of the upper flexible metal sheet 2 and the lower flexible metal sheet 5 can be 1.5mm, 2mm or 2.5mm according to actual needs. In this embodiment, the thickness of the upper flexible metal sheet 2 and the lower flexible metal sheet 5 is preferably 2mm.

[0050] Specifically, S2 further comprises: the thickness of the upper adhesive film 3 can be selected according to actual needs, and then the upper side of the honeycomb core 1 can be glued to the upper flexible metal sheet 2 through the upper adhesive film 3 or not glued according to the thickness of the upper adhesive film 3.

[0051] Similarly, the thickness of the lower adhesive film 4 can be selected according to actual needs, and then the lower side of the honeycomb core 1 can be glued to the lower flexible metal sheet 5 through the lower adhesive film 4 or not glued according to the thickness of the lower adhesive film 4.

[0052] In some embodiments, Figure 2 and Figure 3 As shown in the figure, the protection assembly 6 comprises a protection baffle 61 and a protection baffle 62. The protection baffle 61 is arranged around the sandwich assembly 7 along the height direction of the sandwich assembly 7, and the protection baffle 62 is arranged on the upper end surface of the upper flexible metal sheet 2. By arranging in this way, the collapse of the honeycomb core 1 can be prevented.

[0053] The protection baffle 61 is arranged around the sandwich assembly 7, and a gap is reserved between the protection baffle 61 and the honeycomb core 1. By arranging in this way, the protection baffle 61 will not affect the honeycomb core 1 and thus affect the measurement accuracy of the compression amount of the sandwich assembly 7 after the sandwich assembly 7 is cured, on the premise that the collapse of the honeycomb core 1 is prevented.

[0054] Optionally, the protection baffle 61 is 4, and adjacent two protection baffles 61 are connected through a mortise and tenon structure.

[0055] Optionally, the protection baffle 62 is 4, and the four protection baffles 62 abut each other in sequence. Half of the protection baffle 62 is arranged on the excess area of the honeycomb core 1, and the other half is arranged on the protection baffle 61.

[0056] Further, the gap between the protective baffle 61 and the honeycomb core 1 is 1mm-2mm. By setting the gap between the protective baffle 61 and the honeycomb core 1 in the above range, it can be ensured that the protective baffle 61 will not affect the cured honeycomb core 1, thereby affecting the measurement accuracy of the compression amount of the sandwich assembly 7. The gap between the protective baffle 61 and the honeycomb core 1 can be 1mm, 1.5mm or 2mm, etc. according to actual needs.

[0057] In this embodiment, in order to ensure the structural strength of the protective baffle 61, the material of the protective baffle 61 is set to be aluminum alloy or stainless steel, which has the advantages of good structural strength and corrosion resistance; at the same time, the material of the protective baffle 62 is set to be glass fiber or carbon fiber, which has the advantages of strong heat resistance and good structural strength.

[0058] Specifically, S4 further comprises: first, packaging the to-be-cured part 8; then, curing and forming the packaged to-be-cured part 8 according to the curing curve of the autoclave prepreg. Wherein, the to-be-cured part 8 is packaged according to the typical packaging method of the autoclave curing prepreg.

[0059] Further, the packaging of the to-be-cured part 8 comprises: packaging the to-be-cured part 8 using a vacuum bag film, and vacuumizing the vacuum bag film.

[0060] It should be noted that the vacuum bag process is a molding process in which the product is sealed between the mold and the vacuum bag, and the product is pressurized by vacuumizing to make the product more compact and have better mechanical properties. The specific steps include: 1, mold preparation, apply release agent; 2, product lamination (hand lay-up, spraying, prepreg); 3, lay release cloth; 4, lay isolation film or hole isolation film (can not be laid); 5, lay air felt; 6, paste sealing rubber strip (can be in advance); 7, seal vacuum bag film; 8, install vacuum valve, quick connector and vacuum pipe; 9, connect air source, check vacuum degree; 10, vacuumize, product curing; 11, product demolding.

[0061] In this embodiment, S4 further comprises: after the to-be-cured part 8 is cured, the protective assembly 6 of the cured to-be-cured part 8 is removed, and then the thickness H2 of the cured sandwich assembly 7 is measured, thereby ensuring the accuracy of the measurement.

[0062] The method for measuring the compression amount of the honeycomb core before and after curing of the present application is implemented as follows: 4-grade aramid paper honeycomb core material (nominal thickness of 48kg / m 3For example, the two kinds of honeycomb core raw materials are roughly processed, and the processing size can be determined according to actual conditions, for example, 200mmx100mmx50mm (wherein 50mm is the thickness direction of the honeycomb core); the upper flexible metal sheet 2 and the lower flexible metal sheet 5 are selected as thin aluminum plates with a thickness of 2mm; the upper flexible metal sheet 2, the adhesive film 3, the honeycomb core 1, the lower adhesive film 4 and the lower flexible metal sheet 5 are sequentially laid on a flat tooling; the protection assembly 6 is installed, wherein the gap between the protection baffle 61 and the honeycomb core 1 is 1mm-2mm, and the width of the protection baffle 62 is at least 40mm, half of which is overlapped on the honeycomb core excess area and half of which is overlapped on the protection baffle 61; the to-be-solidified workpiece 8 is packaged according to the vacuum bag process, and then is cured and formed according to the curing curve corresponding to the hot press tank prepreg; finally, the thickness of the cured sandwich assembly 7 is measured, and the thickness difference (i.e. the compression amount) of the sandwich assembly 7 before and after curing is in the range of 0.2mm-0.3mm.

[0063] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. All the embodiments are not required to be enumerated. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method for measuring the compression of a honeycomb core before and after curing, characterized in that: include: S1: Select the type and thickness of the honeycomb core (1); S2: Laying the upper flexible metal sheet (2), the upper adhesive film (3), the honeycomb core (1), the lower adhesive film (4) and the lower flexible metal sheet (5) in sequence to form a sandwich assembly (7), and measuring the thickness H1 of the sandwich assembly (7) before curing; S3: using a protective component (6) to surround the sandwich assembly (7) to form a part to be cured (8); S4: curing the to-be-cured component (8) and measuring the thickness H2 of the sandwich assembly (7) after curing; S5: Calculate the compression S of the sandwich assembly (7) before and after curing, S = H1-H2.

2. The method for measuring the compression of a honeycomb core before and after curing according to claim 1, characterized in that: The upper flexible metal sheet (2) and the lower flexible metal sheet (5) are both thin aluminum sheets or thin copper sheets.

3. The method for measuring the compression of a honeycomb core before and after curing according to claim 2, characterized in that: The thickness of the upper flexible metal sheet (2) and the lower flexible metal sheet (5) are both 1.5 mm to 2.5 mm.

4. The method for measuring the compression of a honeycomb core before and after curing according to claim 1, characterized in that: S2 also includes: According to the thickness of the upper glue film (3), the upper side of the honeycomb core (1) is glued to the upper flexible metal sheet (2) through the upper glue film (3) or not; and / or, Depending on the thickness of the lower glue film (4), the lower side of the honeycomb core (1) is glued to the lower flexible metal sheet (5) through the lower glue film (4) or not.

5. The method for measuring the compression of a honeycomb core before and after curing according to claim 1, characterized in that: The protective assembly (6) comprises a protective baffle (61) and a protective baffle (62), wherein the protective baffle (61) is arranged around the sandwich assembly (7) along the height direction of the sandwich assembly (7), and the protective baffle (62) is arranged on the upper end surface of the protective baffle (61) and the upper flexible metal sheet (2); After the protective strips (61) are arranged around the four sides of the sandwich assembly (7), a gap is reserved between the protective strips (61) and the honeycomb core (1).

6. The method for measuring the compression of a honeycomb core before and after curing according to claim 5, characterized in that: The gap between the protective barrier strip (61) and the honeycomb core (1) is 1 mm to 2 mm.

7. The method for measuring the compression of a honeycomb core before and after curing according to claim 5, characterized in that: The material of the protective baffle (61) is aluminum alloy or stainless steel, and the material of the protective baffle (62) is glass fiber or carbon fiber.

8. The method for measuring the compression of a honeycomb core before and after curing according to claim 1, characterized in that: The S4 also includes: Encapsulating the to-be-cured component (8); The encapsulated part to be cured (8) is cured and formed according to the curing curve of the autoclave prepreg.

9. The method for measuring the compression of a honeycomb core before and after curing according to claim 1, characterized in that: Packaging the to-be-cured component (8) comprises: The to-be-cured article (8) is packaged using a vacuum bag film, and the vacuum bag film is evacuated.

10. The method for measuring the compression of a honeycomb core before and after curing according to claim 1, characterized in that: The S4 also includes: The protective component (6) of the cured workpiece (8) is removed, and the thickness H2 of the cured sandwich assembly (7) is measured.

Images