A quantitative evaluation method for the load-bearing of the inclined bonding connection of composite cabin sections

Abstract

The invention relates to a method for quantitatively evaluating the load-bearing of a composite material cabin section bevel bonding connection; the method comprises the following steps: preparing a composite material test piece and a metal test piece, bonding the composite material test piece and the metal test piece to obtain a component to be tested, obtaining the unit area load-bearing capacity of the bevel of the component to be tested, preparing an actual composite material cabin section and a metal connector, obtaining the actual unit area load-bearing capacity of the bonding surface of the composite material cabin section and the metal connector, performing ratio calculation to obtain a correction coefficient, obtaining the load-bearing capacity of the bonding surface of the composite material cabin section of the product according to the unit area load-bearing capacity of the bevel of the component to be tested and the correction coefficient, comparing the load-bearing capacity of the bonding surface of the composite material cabin section of the product with an index requirement, and completing the quantitative evaluation of the load-bearing of the bonding connection of the bevel of the composite material cabin section; through the above method design, the axial tensile load-bearing capacity of the product after bonding is effectively quantitatively evaluated, the obtained result is more accurate, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a method for quantitatively evaluating the load-bearing of an inclined bonding connection of a composite cabin section. Background Art

[0002] Metal materials are usually connected by welding or mechanical connection, while composite materials and metals are usually connected by bonding or mechanical connection. When composite materials and metals are mechanically connected, holes need to be punched in the composite parts, but punching can lead to local delamination and local stress concentration. Therefore, the most commonly used form is bonding. When evaluating the load-bearing capacity of bonding connections, there has always been a problem of difficulty in accurate quantification. Shear strength or peel strength is usually used to evaluate the performance of adhesives, but actual products are usually in the form of inclined bonding. The current calculation method is to project the inclined surface to the axial direction, and then multiply the axial projection area by the tensile shear strength to obtain the axial load bearing capacity data of the component. However, there are deviations in the above method, mainly because the inclined bonding surface has two failure modes, tensile shear and peeling, when bearing load, and the load cannot be simply obtained using the area projection method.

[0003] For composite cabin sections, the space available for bonding design at both ends is limited. Therefore, it is very important to design the bonding structure. The bonding result should meet the bonding strength and airtightness functions at the same time. The bonding surface angle, bonding surface area, etc. need to be quantitatively designed. A more intuitive and quantitatively evaluated bonding structure design method under axial tension conditions is required.

[0004] CN117030393A discloses a pressurized fixing tool and a sample bonding method, and the Chinese patent document CN 215510725 U discloses a high-temperature curing fixture for rapid batch production of single-lap bonding samples. The main purpose is to quickly and stably prepare tensile shear samples under the standard of GB / T 7142 adhesive tensile shear strength determination. However, this load application form perpendicular to the bonding surface cannot be applied to the bonding of composite material cabin sections and metal end frames.

[0005] Therefore, in view of the above problems, the present invention urgently needs to provide a method for quantitatively evaluating the load-bearing of the inclined bonding connection of a composite material cabin section. Summary of the invention

[0006] The purpose of the present invention is to provide a quantitative evaluation method for the load-bearing of the inclined bonding connection of a composite material cabin section. The quantitative evaluation method for the load-bearing of the inclined bonding connection of a composite material cabin section is proposed to solve the problem that the existing inclined bonding surface has two failure modes, namely, shearing and peeling, when bearing load. The current method for calculating the load-bearing capacity of the inclined surface is to project the inclined surface to the axial direction, and then multiply the axial projection area by the shear strength to obtain the axial load bearing capacity data of the component. However, there is a technical problem that this method deviates from the actual force.

[0007] The present invention provides a method for quantitatively evaluating the load-bearing of the inclined bonding connection of a composite material cabin section, which is characterized by comprising the following steps: S1) designing a bonding slope of a composite cabin section connected to a metal connector, obtaining parameters of the bonding slope of the composite cabin section, and preparing a composite test piece and a metal test piece according to the parameters of the bonding slope of the composite cabin section; S2) Apply glue on the bonding slope of the composite test piece to form a glue layer, bond the metal test piece and the composite test piece together to obtain the component to be tested. After the glue layer is cured, use a fixed tool to clamp and fix the component to be tested in the transverse and longitudinal directions, and load the component to be tested transversely. After the glue layer thickness meets the requirements, stop the transverse loading, and record the glue layer thickness and transverse axial tightening load of the component to be tested; S3) Perform tensile test on the component to be tested in accordance with the requirements of GB / T 7142 and record the tensile failure load of the component to be tested; S4) According to formula f 测 =T 测 / S 测 , obtain the unit area load capacity f of the inclined surface of the component to be tested 测 , where T 测 is the tensile failure load of the component to be tested, S 测 is the bonding slope area of ​​the composite cabin; S5) According to the bonding slope area parameter of the composite cabin section, prepare the actual composite cabin section and the metal connector, apply glue, fix the composite cabin section and the metal connector to obtain the product, and after the glue is cured, load the product according to the axial tightening load obtained in step S2, and after loading, measure the tensile failure load T of the product 产品 , according to formula f 产品 =T 产品 / S 产品 , obtain the unit area load capacity f of the product slope 产品 , f 测 With f 产品 Perform ratio operation to obtain the correction coefficient k; S6) According to formula T 产品 =kf 测 ×S 产品, obtain the bearing capacity T of the bonding surface of the composite cabin section of the product 产品 , S 产品 is the bonding slope parameter of the composite cabin; S7) If T 产品 <Indicator requirements, redesign the slope parameters of the composite cabin bonding slope, and repeat steps S1 to S6 until T 产品 Greater than the index requirement.

[0008] Preferably, the thickness of the composite material test piece is determined according to the bonding surface parameters and the bonding surface angle, and the thickness of the composite material test piece is ≤5 mm.

[0009] Preferably, the fixing tool comprises a bottom plate, vertical plates are arranged on opposite sides of the bottom plate, each vertical plate is provided with a first screw hole, each first screw hole penetrates the corresponding vertical plate, each first screw hole is screwed with a first top screw, and also comprises positioning frames arranged at intervals along the length of the bottom plate, each positioning frame has three end faces provided with second screw holes penetrating the positioning frame, each second screw hole is screwed with a second top screw; It also includes a fixing frame located in each positioning frame, the lower end surface of the fixing frame is provided with a fixing cavity matching the size of the component to be tested, and each fixing frame is fixed to the bottom plate by a corresponding second top screw.

[0010] Preferably, when the thickness of the adhesive layer loaded on the component to be tested is less than 0.2 mm, the lateral loading is stopped.

[0011] Preferably, before bonding, the bonding surface of the composite material test piece is roughened and cleaned with an organic solvent; The bonding surface of the metal test piece was sandblasted with 320-mesh corundum.

[0012] Preferably, after the adhesive layer is cured, the component to be tested is polished.

[0013] Preferably, T 产品 >After meeting the index requirements, mass production will be carried out.

[0014] Preferably, the curing time of the glue layer is determined according to the type of glue.

[0015] Preferably, the composite material test piece is made of carbon fiber reinforced resin material.

[0016] Preferably, the material of the metal test piece is steel.

[0017] The method for quantitatively evaluating the load-bearing of the inclined bonding connection of a composite cabin section provided by the present invention has the following improvements compared with the prior art: 1. The present invention can more intuitively link the test components and product process parameters through the design of the load-bearing quantitative evaluation method for the inclined bonding connection of the composite material cabin section, and can optimize the bonding parameters in a targeted manner according to the parameters of the test piece and the test results, change the bonding area, and conduct an effective quantitative evaluation of the axial tensile bearing capacity of the product after bonding. The bonding surface of the composite material cabin section is quantitatively calculated, and the results obtained are more accurate, thereby reducing the manufacturing cost. At the same time, the axial loading used by the tooling for bonding the specimen can also be used as a reference for the bonding load parameters when the composite material cabin section product is bonded to the end frame.

[0018] 2. The present invention can fasten the component to be tested on the bottom plate through the design of the fixed tooling, limit the axial outward displacement of the component to be tested, and realize directional glue overflow, which is consistent with the glue overflow form during product bonding, thereby ensuring the accuracy of the test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a flowchart of the steps of the method for quantitatively evaluating the load-bearing of the composite material cabin section inclined surface bonding connection according to the present invention; Figure 2 It is a structural schematic diagram (stereoscopic diagram) of the fixing tool described in the present invention.

[0021] Description of reference numerals: 1. Bottom plate; 2. Vertical plate; 3. First top screw; 4. Positioning frame; 5. Second top screw; 6. Fixed frame. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, the present invention provides a method for quantitatively evaluating the load-bearing of the inclined bonding connection of a composite material cabin section, comprising the following steps: S1) designing a bonding slope of a composite cabin section connected to a metal connector, obtaining parameters of the bonding slope of the composite cabin section, and preparing a composite test piece and a metal test piece according to the parameters of the bonding slope of the composite cabin section; S2) Apply glue on the bonding slope of the composite test piece to form a glue layer, bond the metal test piece and the composite test piece together to obtain the component to be tested. After the glue layer is cured, use a fixed tool to clamp and fix the component to be tested in the transverse and longitudinal directions, and load the component to be tested transversely. After the glue layer thickness meets the requirements, stop the transverse loading, and record the glue layer thickness and transverse axial tightening load of the component to be tested; S3) Perform tensile test on the component to be tested in accordance with the requirements of GB / T 7142 and record the tensile failure load of the component to be tested; S4) According to formula f 测 =T 测 / S 测 , obtain the unit area load capacity f of the inclined surface of the component to be tested 测 , where T 测 is the tensile failure load of the component to be tested, S 测 is the bonding slope area of ​​the composite cabin; S5) According to the bonding slope area parameter of the composite cabin section, prepare the actual composite cabin section and the metal connector, apply glue, fix the composite cabin section and the metal connector to obtain the product, and after the glue is cured, load the product according to the axial tightening load obtained in step S2, and after loading, measure the tensile failure load T of the product 产品 , according to formula f 产品 =T 产品 / S 产品 , obtain the unit area load capacity f of the product slope 产品 , f 测 With f 产品 Perform ratio operation to obtain the correction coefficient k; S6) According to formula T 产品 =kf 测 ×S 产品 , obtain the bearing capacity T of the bonding surface of the composite cabin section of the product 产品 , S 产品 is the bonding slope parameter of the composite cabin; S7) If T 产品 <Indicator requirements, redesign the slope parameters of the composite cabin bonding slope, and repeat steps S1 to S6 until T 产品 Greater than the index requirement.

[0024] The present invention can more intuitively link the test components and product process parameters through the design of the composite cabin inclined surface bonding connection load quantitative evaluation method, and can optimize the bonding parameters in a targeted manner according to the test piece parameters and test results, change the bonding area, and effectively quantitatively evaluate the axial tensile bearing capacity of the product after bonding, quantitatively calculate the bonding surface of the composite cabin, and obtain more accurate results, thereby reducing manufacturing costs. At the same time, the axial loading used by the tooling for bonding the sample can also be used as a reference for bonding load parameters when the composite cabin product is bonded to the end frame.

[0025] The present invention uses a method for quantitatively evaluating the load-bearing of composite cabin section inclined surface bonding connections, which can be used for promotion and application in composite cabin sections with tensile load requirements, and has high application value and promotion significance.

[0026] Specifically, the thickness of the composite material test piece is determined according to the bonding surface parameters and the bonding surface angle, and the thickness of the composite material test piece is ≤5 mm.

[0027] Specifically, Figure 2 As shown, the fixing tool includes a base plate 1, and vertical plates 2 are provided on opposite sides of the base plate 1, each vertical plate 2 is provided with a first screw hole, each first screw hole penetrates the corresponding vertical plate 2, and each first screw hole is screwed with a first top screw 3, and also includes positioning frames 4 arranged at intervals along the length of the base plate 1, and three end faces of each positioning frame 4 are provided with second screw holes penetrating the positioning frame 4, and each second screw hole is screwed with a second top screw 5; it also includes a fixing frame 6 located in each positioning frame 4, and the lower end face of the fixing frame 6 is provided with a fixing cavity matching the size of the component to be tested, and each fixing frame 6 is fixed to the base plate 1 by the corresponding second top screw 5, and the fixing frame 6 is replaced according to the test component, and the fixing frame 6 is movably connected to the base plate 1.

[0028] In this embodiment, the longitudinal height of the inner top surface of the positioning frame 4 is greater than the longitudinal height of the top surface of the vertical board 2, and the difference between the longitudinal height of the inner top surface of the positioning frame 4 and the top surface of the vertical board 2 is greater than the thickness of the composite material test piece and the metal test piece.

[0029] The present invention can fasten the component to be tested on the bottom plate through the design of the fixed tooling, limit the non-axial outward displacement of the component to be tested, achieve directional glue overflow, keep consistent with the glue overflow form when the product is bonded, and ensure the accuracy of the test data.

[0030] The length of the fixing frame 6 of this embodiment should not be greater than the length of the axial projection of the bonding surface, so as to ensure that the bonding seam of the component to be tested is exposed, without affecting the glue overflow at the bonding seam, and at the same time limit the glue overflow at other positions.

[0031] Specifically, when the thickness of the adhesive layer loaded on the component to be tested is less than 0.2 mm, the lateral loading is stopped.

[0032] Specifically, before bonding, the bonding surface of the composite material test piece was roughened and cleaned with an organic solvent; The bonding surface of the metal test piece was sandblasted with 320-mesh corundum.

[0033] Specifically, after the adhesive layer is cured, the component to be tested is polished.

[0034] Specifically, T 产品 >After meeting the index requirements, mass production will be carried out.

[0035] Specifically, the curing time of the glue layer is determined according to the type of glue.

[0036] Specifically, the composite material test piece is prepared by using carbon fiber reinforced resin material.

[0037] Specifically, the material of the metal test piece is steel.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for quantitatively evaluating the load-bearing of composite material cabin section inclined bonding connection, characterized in that: The steps include: S1) designing a bonding slope of a composite cabin section connected to a metal connector, obtaining parameters of the bonding slope of the composite cabin section, and preparing a composite test piece and a metal test piece according to the parameters of the bonding slope of the composite cabin section; S2) Apply glue on the bonding slope of the composite test piece to form a glue layer, bond the metal test piece and the composite test piece together to obtain the component to be tested. After the glue layer is cured, use a fixed tool to clamp and fix the component to be tested in the transverse and longitudinal directions, and load the component to be tested transversely. After the glue layer thickness meets the requirements, stop the transverse loading, and record the glue layer thickness and transverse axial tightening load of the component to be tested; S3) Perform tensile test on the component to be tested in accordance with the requirements of GB / T 7142 and record the tensile failure load of the component to be tested; S4) According to formula f 测 =T 测 / S 测 , obtain the unit area load capacity f of the inclined surface of the component to be tested 测 , where T 测 is the tensile failure load of the component to be tested, S 测 is the bonding slope area of ​​the composite cabin; S5) According to the bonding slope area parameter of the composite cabin section, prepare the actual composite cabin section and the metal connector, apply glue, fix the composite cabin section and the metal connector to obtain the product, and after the glue is cured, load the product according to the axial tightening load obtained in step S2, and after loading, measure the tensile failure load T of the product 产品 , according to formula f 产品 =T 产品 / S 产品 , obtain the unit area load capacity f of the product slope 产品 , f 测 With f 产品 Perform ratio operation to obtain the correction coefficient k; S6) According to formula T 产品 =kf 测 ×S 产品 , obtain the bearing capacity T of the bonding surface of the composite cabin section of the product 产品 , S 产品 is the bonding slope parameter of the composite cabin; S7) If T 产品 <Indicator requirements, redesign the slope parameters of the composite cabin bonding slope, and repeat steps S1 to S6 until T 产品 Greater than the index requirement.

2. The method for quantitatively evaluating the load-bearing of composite material cabin section inclined surface bonding connection according to claim 1 is characterized in that: The thickness of the composite material test piece is determined according to the bonding surface parameters and the bonding surface angle. The thickness of the composite material test piece is ≤5mm.

3. The method for quantitatively evaluating the load-bearing of composite material cabin section inclined bonding connection according to claim 1 is characterized in that: The fixing tool comprises a bottom plate (1), vertical plates (2) are arranged on opposite sides of the bottom plate (1), each vertical plate (2) is provided with a first screw hole, each first screw hole passes through the corresponding vertical plate (2), each first screw hole is screwed with a first top screw (3), and also comprises positioning frames (4) arranged at intervals along the length of the bottom plate (1), three end faces of each positioning frame (4) are provided with second screw holes passing through the positioning frame (4), and each second screw hole is screwed with a second top screw (5); It also includes a fixing frame (6) located in each positioning frame (4), the lower end surface of the fixing frame (6) is provided with a fixing cavity matching the size of the component to be tested, and each fixing frame (6) is fixed to the bottom plate (1) via a corresponding second top screw (5).

4. The method for quantitatively evaluating the load-bearing of composite material cabin section inclined bonding connection according to claim 1 is characterized in that: When the thickness of the adhesive layer loaded on the component to be tested is less than 0.2 mm, stop lateral loading.

5. The method for quantitatively evaluating the load-bearing of composite material cabin section inclined surface bonding connection according to claim 1 is characterized in that: Before bonding, the bonding surface of the composite test piece was roughened and cleaned with an organic solvent; The bonding surface of the metal test piece was sandblasted with 320-mesh corundum.

6. The method for quantitatively evaluating the load-bearing of composite material cabin section inclined surface bonding connection according to claim 1 is characterized in that: After the glue layer is cured, the components to be tested are polished.

7. The method for quantitatively evaluating the load-bearing of composite material cabin section inclined bonding connection according to claim 1, characterized in that: T 产品 >After meeting the index requirements, mass production will be carried out.

8. The method for quantitatively evaluating the load-bearing of composite cabin section inclined bonding connection according to claim 1 is characterized in that: Determine the curing time of the glue layer according to the type of glue.

9. The method for quantitatively evaluating the load-bearing of composite material cabin section inclined bonding connection according to claim 1, characterized in that: The composite test piece is made of carbon fiber reinforced resin material.

10. The method for quantitatively evaluating the load-bearing of composite material cabin section inclined bonding connection according to claim 1, characterized in that: The material of the metal test piece is steel.

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