Customized design optimal miter angle method for composite material miter joint

Abstract

The invention relates to a method for customizing and designing an optimal miter angle of a composite miter joint. The method comprises the following steps: acquiring the tensile strength of an adherend and the shear strength and tensile strength of an adhesive; determining a first target parameter according to the tensile strength of the adherend and the shear strength of the adhesive, and determining a second target parameter according to the tensile strength of the adherend and the tensile strength of the adhesive; and based on the first target parameter and the second target parameter, obtaining a miter joint angle of a miter joint. According to the method, the miter angle of the miter joint can be optimized, so that the mechanical properties of an adhered object and an adhesive are exerted to the maximum extent, and the strength of the miter joint is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material connection, in particular to a method for customizing and designing optimal oblique joint angle of composite material oblique joint. BACKGROUND

[0002] Composite material is a new material composed of two or more different components, which has excellent mechanical properties and corrosion resistance. However, the joint problem of composite material has been an important challenge in manufacturing and application. Adhesive joint is a joint way of connecting two or more materials together by adhesive. In the field of composite materials, adhesive joint is widely concerned because it can maintain the overall performance of composite materials, reduce weight and improve durability. With the development of composite material technology, adhesive joint is also constantly improving. In recent years, with the development of 3D printing technology, the manufacturing process of adhesive joint is also constantly improving. 3D printing technology makes it possible to introduce complex geometric structures in composite material joints, thereby improving the mechanical properties and durability of the joints.

[0003] Lap joint is a common connection way of adhesive joint, which overlaps a part of two components and bonds them together using adhesive. There are many lap joint ways, such as single lap joint, double lap joint, oblique lap joint, stepped lap joint, etc. The improvement of lap joint is to continuously improve the strength of the joint. Among them, oblique joint is concerned for its excellent strength. However, the problem of oblique joint is that when the adherend or adhesive does not reach the theoretical strength at the same time, the oblique joint will be damaged prematurely. This is because the oblique joint angle is an empirical value, and the optimal oblique joint angle is not used in engineering.

[0004] Therefore, it is necessary to design a method for customizing and designing optimal oblique joint angle of composite material oblique joint, so that the oblique joint angle of the oblique joint reaches the optimal value, thereby maximizing the mechanical properties of the adherend and the adhesive, and greatly improving the strength of the oblique joint. SUMMARY

[0005] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a method for customizing and designing optimal oblique joint angle of composite material oblique joint, which greatly improves the strength of the oblique joint.

[0006] To achieve the above purpose, the present application provides the following scheme:

[0007] A method for customizing and designing optimal oblique joint angle of composite material oblique joint, comprising:

[0008] obtaining the tensile strength of the adherend and the shear strength and tensile strength of the adhesive;

[0009] The first target parameter is determined according to the tensile strength of the adherend and the shear strength of the adhesive, and the second target parameter is determined according to the tensile strength of the adherend and the tensile strength of the adhesive;

[0010] The miter angle of the miter joint is obtained based on the first target parameter and the second target parameter.

[0011] Optionally, the adherends on the same side of the adherend are homogeneous materials.

[0012] Optionally, determining the first target parameter comprises:

[0013]

[0014] wherein λ1 is the first target parameter, is the tensile strength of the adherend, is the shear strength of the adhesive.

[0015] Optionally, determining the second target parameter comprises:

[0016]

[0017] wherein λ2 is the second target parameter, is the tensile strength of the adhesive.

[0018] Optionally, if the material properties of the adherends on two sides are different, the obtained tensile strength of the adherend refers to the tensile strength of the side with lower tensile strength; if the material properties of the adherends on two sides are the same, the obtained tensile strength of the adherend refers to the tensile strength of one side of the adherend.

[0019] Optionally, obtaining the miter angle of the miter joint comprises:

[0020]

[0021] wherein k' is the ratio of the tensile strength and the shear strength of the adhesive, θ1 and θ2 are the two calculated miter angles, θ is the optimal miter angle of the miter joint, since θ1 and θ2 cannot simultaneously satisfy the respective value ranges, θ takes the only one that satisfies the condition, and when θ1 = θ2 = arctank', it is considered that the two coincide.

[0022] Optionally, obtaining the ratio of the tensile strength and the shear strength of the adhesive comprises:

[0023]

[0024] wherein, is the tensile strength of the adhesive, is the shear strength of the adhesive.

[0025] Optionally, the miter joints corresponding to the miter angle include: single miter joints, double miter joints, and multiple miter joints.

[0026] Optionally, the adhesive interface in the miter joint angle is an inclined plane.

[0027] The beneficial effects of this invention are as follows:

[0028] (1) Compared with conventional single lap joints, the present invention is designed as a mitered joint, which can greatly improve the joint strength.

[0029] (2) When a conventional miter joint fails, at least one of the adhered material and the adhesive fails to reach its maximum strength. This invention can customize the optimal miter angle according to the mechanical parameters of the material, so that the adhered material and the adhesive can exert their full mechanical properties even when they fail.

[0030] (3) The present invention can greatly improve the strength of the miter joint compared with the conventional design, and has engineering application value. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart illustrating a customized design method for optimizing the miter joint angle of a composite material miter joint according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of a miter joint according to an embodiment of the present invention;

[0034] Figure 3 This is a front view of the miter joint according to an embodiment of the present invention;

[0035] Figure 4 Other forms of miter joints according to embodiments of the present invention; (a) is a double miter joint, (b) is a double-tooth miter joint, and (c) is a multi-tooth miter joint;

[0036] Figure 5 This is a supplementary schematic diagram for the present invention;

[0037] Wherein, 1-the horizontal segment of the first object to be adhered to; 2-the tapered segment of the first object to be adhered to; 3-the adhesive; 4-the tapered segment of the second object to be adhered to; 5-the horizontal segment of the second object to be adhered to; 6-the miter angle. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1 As shown in the figure, this embodiment discloses a customized design method for the optimal miter angle of a composite material miter joint, including: obtaining the tensile strength of the adherend and the shear strength and tensile strength of the adhesive; determining a first target parameter based on the tensile strength of the adherend and the shear strength of the adhesive; determining a second target parameter based on the tensile strength of the adherend and the tensile strength of the adhesive; and obtaining the miter angle of the miter joint based on the first target parameter and the second target parameter.

[0041] Specifically, this embodiment discloses a customized design method for the optimal miter angle of composite material miter joints, which includes three important design steps:

[0042] (a) Based on the tensile strength of the adherend with lower tensile strength and the shear strength of adhesives The parameter λ1 is determined as follows:

[0043]

[0044] (b) Based on the tensile strength of the adherend with lower tensile strength Tensile strength of adhesives The parameter λ2 is determined as follows:

[0045]

[0046] (c) To customize the design of the miter joint angle, for a miter joint made of a given material, its optimal miter angle θ can be determined:

[0047]

[0048] Where k′ is the ratio of the tensile strength to the shear strength of the adhesive. θ1 and θ2 are the two calculated miter angles, and θ is the optimal miter angle for the joint. Since θ1 and θ2 cannot simultaneously satisfy their respective ranges, θ is chosen as the only one that satisfies the condition. When θ1=θ2=arctank′, they are considered to coincide.

[0049] The strength of the miter joint reaches its maximum when the miter angle is θ.

[0050] Furthermore, the adherends on the same side are homogeneous and of the same material.

[0051] Specifically, the adhered materials on both sides can be the same or different materials. Adhesive materials on the same side must be homogeneous and of the same material. The adhesive must also be homogeneous. The adhered materials on both sides should be conical within the bonding area to ensure a mitered joint with the adhesive, with a straight interface. Ideally, the adhesive interface should be perpendicular to the sloping surface of the conical adhered material, or it can be at a certain angle. The adhesive strength to the joint should be high to prevent the adhesive from detaching entirely from the joint. The external load on the adhered materials must be a uniform horizontal tensile load on both sides.

[0052] like Figure 3 As shown, the miter angle refers to the angle between the beveled surface of the adhesive and the horizontal direction of the adherend. The miter angle must be an acute angle; it cannot be a 0-degree horizontal overlap or a 90-degree left-right butt joint.

[0053] This embodiment discloses a customized design method for optimizing the miter angle of composite material miter joints, including:

[0054] like Figure 2 As shown, the composite material miter joint includes miter-joints placed vertically on top of each other, and an adhesive between the joints; more specifically, it includes: a horizontal segment 1 of the first joint, a tapered segment 2 of the first joint, an adhesive 3, a tapered segment 4 of the second joint, a horizontal segment 5 of the second joint, and a miter angle 6.

[0055] The adhered materials and adhesive together form a miter joint. The adhesive bonding area includes the tapered section of the adhered materials and the adhesive; the horizontal section of the adhered materials is not within the bonding area. The bonding interface must be a beveled surface; the interface must be inclined and flat.

[0056] Furthermore, both ends of this miter joint can withstand uniform tensile loads.

[0057] This method for designing miter joints includes, but is not limited to, the following: Figure 2 The single-miter joint type also includes Figure 4 (a) shows the double miter joint. Figure 4 (b) shows a double-toothed miter joint and other miter joints. Figure 4 (c) The design of the mitered joint angle of the multi-tooth mitered joint and other mitered joints shown can be implemented in accordance with the present invention.

[0058] This invention, through mechanical analysis, identifies two failure modes of miter joints: failure of the adhered material and failure of the adhesive. Based on the strengths of the adhered material and the adhesive, the miter angle of the joint can be customized to cause simultaneous failure of both the adhered material and the adhesive, resulting in simultaneous bulk and interfacial damage. This fully utilizes the material's strength, maximizing the overall strength of the miter joint.

[0059] The specific technical solution of this invention is as follows:

[0060] Step 1: Based on the tensile strength of the adhesive and shear strength The ratio determines the parameter k', specifically:

[0061]

[0062] Step 2: Based on the tensile strength of the adherend with lower tensile strength... and the shear strength of adhesives The parameter λ1 is determined as follows:

[0063]

[0064] Step 3: Based on the tensile strength of the adherend with lower tensile strength... Tensile strength of adhesives The parameter λ1 is determined as follows:

[0065]

[0066] Step 4: Determine the angle of the miter joint.

[0067] To customize the design of the miter joint angle, for a miter joint made of a given material, the miter angle θ can be determined based on the two values ​​λ1 and λ2 obtained in step four:

[0068]

[0069] Where k′ is the ratio of the tensile strength to the shear strength of the adhesive. θ1 and θ2 are the two calculated miter angles, and θ is the optimal miter angle for the joint. Since θ1 and θ2 cannot simultaneously satisfy their respective ranges, θ is chosen as the only one that satisfies the condition. When θ1=θ2=arctank′, they are considered to coincide.

[0070] The following example illustrates this: If the adherend is a relatively hard resin material RGD8530 with a tensile strength of 17.3 MPa, and the adhesive is a relatively soft resin material FLX9895 with a tensile strength of 12.7 MPa and a shear strength of 7.7 MPa, then according to mechanical analysis, the following can be obtained: Figure 5The diagrams showing the strength of the miter joint under different miter angles reveal that a miter joint with an angle of 58.96°, designed according to this invention, achieves the maximum strength. Under other miter joint angle designs, the joint strength is lower than that of the method described in this invention.

[0071] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A customized design method for optimizing the miter joint angle of composite material miter joints, characterized in that, include: To obtain the tensile strength of the bonded material and the shear strength and tensile strength of the adhesive; A first target parameter is determined based on the tensile strength of the adherend and the shear strength of the adhesive; a second target parameter is determined based on the tensile strength of the adherend and the tensile strength of the adhesive. Based on the first target parameter and the second target parameter, the miter angle of the miter joint is obtained.

2. The customized design method for the optimal miter angle of composite material miter joints according to claim 1, characterized in that, The adherends on the same side are homogeneous and of the same material.

3. The customized design method for the optimal miter angle of composite material miter joints according to claim 1, characterized in that, Determining the first target parameter includes: Where λ1 is the first objective parameter, The tensile strength of the adherend. This represents the shear strength of the adhesive.

4. The customized design method for the optimal miter angle of composite material miter joints according to claim 1, characterized in that, Determining the second target parameter includes: Where λ2 is the second objective parameter, This represents the tensile strength of the adhesive.

5. The method for customized design of optimal miter joint angle for composite material miter joints according to claim 3, characterized in that, If the materials of the two adherends are different, the tensile strength of the adherends obtained refers to the side with the lower tensile strength; if the materials of the two adherends are the same, the tensile strength of the adherends obtained refers to the tensile strength of one of the adherends.

6. The method for customized design of optimal miter joint angle for composite material miter joints according to claim 1, characterized in that, Obtaining the miter angle of the miter joint includes: Where k′ is the ratio of the tensile strength to the shear strength of the adhesive, θ1 and θ2 are the two calculated miter angles, and θ is the optimal miter angle of the miter joint. Since θ1 and θ2 cannot simultaneously satisfy their respective value ranges, θ is taken as the only one that satisfies the condition. When θ1=θ2=arctank′, it is considered that the two coincide.

7. The method for customized design of optimal miter joint angle for composite material miter joints according to claim 5, characterized in that, Obtaining the ratio of the tensile strength to the shear strength of the adhesive includes: in, The tensile strength of the adhesive. This represents the shear strength of the adhesive.

8. The method for customized design of optimal miter joint angle for composite material miter joints according to claim 1, characterized in that, The miter joints corresponding to the miter angles include: single miter joints, double miter joints, and multiple miter joints.

9. The method for customized design of optimal miter joint angle for composite material miter joints according to claim 1, characterized in that, The adhesive interface in the miter joint angle is an inclined plane.

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