Connecting method for continuous fiber reinforced thermoplastic resin-based composite material and formed connector

Abstract

The present application relates to the technical field of composite material welding. Provided is a connecting method for a continuous fiber reinforced thermoplastic resin-based composite material. In the present application, a hollow circular tube of a continuous fiber reinforced thermoplastic resin-based composite material is used as a connector, which effectively reduces the weight of a formed connector, avoids the galvanic corrosion that is prone to occur between the composite material and conventional metal fasteners, and has good corrosion resistance and fatigue resistance; and the advantages of being rapid, efficient, easy to operate and having a simple process flow are provided, thus facilitating continuous production in a factory.

Description

A method for connecting continuous fiber reinforced thermoplastic resin-based composite materials and a molded connecting part

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on September 22, 2023, with application number CN202311229625.0 and invention name “A method for connecting continuous fiber reinforced thermoplastic resin-based composite materials”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of composite material welding, and in particular to a method for connecting continuous fiber reinforced thermoplastic resin-based composite materials. Background Art

[0003] Fiber-reinforced resin-based composites are used in aerospace, construction, automotive, and other fields due to their high specific strength, specific modulus, and good chemical stability. The production of large or complex structural parts often requires the assembly of homogeneous or heterogeneous materials through mechanical joining, adhesive bonding, or welding. Traditional metal fasteners such as bolts and rivets create heavy connections, are susceptible to galvanic corrosion, and are difficult to repair. Adhesive bonding requires surface treatment, which takes a long time, and the joint quality is easily affected by the environment.

[0004] Summary of the Invention

[0005] The purpose of this application is to provide a method for connecting continuous fiber reinforced thermoplastic resin-based composite materials. The molded connecting parts formed by the connection method provided by this application are lightweight and have good corrosion resistance and fatigue resistance; and have the advantages of being fast, efficient, easy to operate, and having a simple process flow, which is conducive to realizing continuous production in factories.

[0006] In order to achieve the above-mentioned invention objectives, this application provides the following technical solutions:

[0007] The present application provides a method for connecting continuous fiber reinforced thermoplastic resin-based composite materials, comprising the following steps:

[0008] providing a first through hole in the area to be welded of the first fiber reinforced thermoplastic resin-based composite material component;

[0009] providing a second through hole in the area to be welded of the second fiber-reinforced thermoplastic resin-based composite material component;

[0010] Overlapping the to-be-welded region of the first fiber-reinforced thermoplastic resin-based composite material component and the to-be-welded region of the second fiber-reinforced thermoplastic resin-based composite material component so that the first through hole and the second through hole are interconnected;

[0011] Passing a hollow circular tube of continuous fiber reinforced thermoplastic resin-based composite material through the first through hole and the second through hole, with both ends of the hollow circular tube of continuous fiber reinforced thermoplastic resin-based composite material extending out of the first fiber reinforced thermoplastic resin-based composite material component and the second fiber reinforced thermoplastic resin-based composite material component, respectively, to obtain a connection piece to be welded;

[0012] An ultrasonic welding head is used to crush the hollow circular tube of continuous fiber reinforced thermoplastic resin-based composite material extending outside the first fiber reinforced thermoplastic resin-based composite material component and the second fiber reinforced thermoplastic resin-based composite material component. Part of the resulting crushed material fills the hollow area of ​​the hollow circular tube, and the remaining resulting crushed material forms a fixed joint in the area to be welded of the first fiber reinforced thermoplastic resin-based composite material component and the area to be welded of the second fiber reinforced thermoplastic resin-based composite material component to obtain a molded connector.

[0013] Preferably, the first through hole and the second through hole have the same diameter.

[0014] Preferably, the outer diameter of the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube is smaller than or equal to the diameter of the first through hole and the second through hole.

[0015] Preferably, the ratio of the outer diameter to the wall thickness of the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material is between 4.0 and 10.0.

[0016] Preferably, the mass content of the fiber in the continuous fiber reinforced thermoplastic resin-based composite hollow tube is 35-70%.

[0017] Preferably, the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube is prepared by a single-layer prepreg winding method, and the 0-degree fibers are arranged along the length direction of the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube.

[0018] Preferably, the thermoplastic resin used in the first fiber-reinforced thermoplastic resin-based composite material component and the thermoplastic resin used in the second fiber-reinforced thermoplastic resin-based composite material component are the same.

[0019] Preferably, the thermoplastic resin used in the continuous fiber reinforced thermoplastic resin-based composite hollow tube is the same as the thermoplastic resin used in the first fiber reinforced thermoplastic resin-based composite component and the thermoplastic resin used in the second fiber reinforced thermoplastic resin-based composite component.

[0020] Preferably, the fixed joint is disc-shaped.

[0021] Preferably, the welding frequency of the ultrasonic welding head is 15-30 kHz, the amplitude is 20-40 μm, and the welding pressure is 100-1000N.

[0022] The present application provides a method for connecting continuous fiber reinforced thermoplastic resin-based composite materials. The present application uses hollow circular tubes of continuous fiber reinforced thermoplastic resin-based composite materials as connectors, which effectively reduces the weight of the molded connectors and avoids the galvanic corrosion that is prone to occur between the composite materials and conventional metal fasteners. At the same time, ultrasonic welding technology is used, which is simple and efficient, and the prepared molded connectors have excellent mechanical properties.

[0023] The molded connectors prepared in this application all use fiber-reinforced thermoplastic resin-based composite materials, which are lighter in weight, have good corrosion resistance and fatigue resistance, and improve the overall chemical stability of the molded connectors.

[0024] In addition, the fastener used in this application is a hollow circular tube. During welding with an ultrasonic welding head, under the action of heat and pressure transferred by the welding head, the hollow circular tube that is higher than the height of the component collapses uniformly and gradually from the top, and continuous fragments are formed along the middle of the wall thickness of the hollow circular tube, which expand toward the inside and outside of the hollow circular tube. The inward-bent fragments fill the hollow area of ​​the hollow circular tube, while the outward-bent part forms a joint close to a disc on the surface of the connected fiber-reinforced thermoplastic resin-based composite material component, ensuring the maximum contact area between the fastener (hollow circular tube) and the connected component, thereby improving the stability of the molded connector.

[0025] In the molded connector provided in the present application, the disc-shaped joint formed between the portion of the crushed hollow circular tube that expands toward the outside of the hollow circular tube and the connected fiber-reinforced thermoplastic resin-based composite material component contains continuous fibers, which plays the role of bearing the main load when the molded connector is subjected to tension or the like, thereby improving the shear strength of the circular tube itself and reducing the possibility of normal peeling of the connection structure.

[0026] In the molded connector provided in the present application, the part of the crushed hollow circular tube that is squeezed toward the inside of the circular tube gradually fills up the hollow portion of the hollow circular tube in the punched area, thereby enhancing the shear and bending resistance of the circular tube and further increasing the connection effect.

[0027] This application uses ultrasonic welding as the connection method. The applied ultrasonic vibration helps to promote the welding of the thermoplastic resin matrix between the hollow circular tube and the connected fiber-reinforced thermoplastic resin-based composite material component, thereby improving the overall strength of the molded connection. It has the advantages of being fast and efficient, easy to operate, and having a simple process flow, which is conducive to achieving continuous production in the factory. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic diagram of a method for connecting continuous fiber reinforced thermoplastic resin-based composite materials provided by the present application;

[0029] FIG2 is a cross-sectional view of a connector to be welded according to the present application;

[0030] FIG3 is a top view of the connector to be welded in the present application;

[0031] FIG4 is a cross-sectional view of the molded connector of the present application;

[0032] FIG5 is a top view of the molded connector of the present application;

[0033] FIG6 is a physical picture and a simulation picture of the molded connector of the present application;

[0034] In Figures 2 to 6, 1-first fiber-reinforced thermoplastic resin-based composite material component; 2-second fiber-reinforced thermoplastic resin-based composite material component; 3-continuous fiber-reinforced thermoplastic resin-based composite hollow tube; 11-first through hole; 21-second through hole. DETAILED DESCRIPTION

[0035] The present application provides a method for connecting continuous fiber reinforced thermoplastic resin-based composite materials, comprising the following steps:

[0036] providing a first through hole in the area to be welded of the first fiber reinforced thermoplastic resin-based composite material component;

[0037] providing a second through hole in the area to be welded of the second fiber-reinforced thermoplastic resin-based composite material component;

[0038] Overlapping the to-be-welded region of the first fiber-reinforced thermoplastic resin-based composite material component and the to-be-welded region of the second fiber-reinforced thermoplastic resin-based composite material component so that the first through hole and the second through hole are interconnected;

[0039] Passing a hollow circular tube of continuous fiber reinforced thermoplastic resin-based composite material through the first through hole and the second through hole, with both ends of the hollow circular tube of continuous fiber reinforced thermoplastic resin-based composite material extending out of the first fiber reinforced thermoplastic resin-based composite material component and the second fiber reinforced thermoplastic resin-based composite material component, respectively, to obtain a connection piece to be welded;

[0040] An ultrasonic welding head is used to crush the hollow circular tube of continuous fiber reinforced thermoplastic resin-based composite material extending outside the first fiber reinforced thermoplastic resin-based composite material component and the second fiber reinforced thermoplastic resin-based composite material component. Part of the resulting crushed material fills the hollow area of ​​the hollow circular tube, and the remaining resulting crushed material forms a fixed joint in the area to be welded of the first fiber reinforced thermoplastic resin-based composite material component and the area to be welded of the second fiber reinforced thermoplastic resin-based composite material component to obtain a molded connector.

[0041] In this application, a first through-hole is provided in the area to be welded of a first fiber-reinforced thermoplastic resin-based composite material component; and a second through-hole is provided in the area to be welded of a second fiber-reinforced thermoplastic resin-based composite material component. In this application, the thermoplastic resin used in the first fiber-reinforced thermoplastic resin-based composite material component and the thermoplastic resin used in the second fiber-reinforced thermoplastic resin-based composite material component are preferably the same. In this application, the first through-hole and the second through-hole preferably have the same diameter.

[0042] In the present application, the reinforcing fibers used in the first fiber-reinforced thermoplastic resin-based composite material component and the second fiber-reinforced thermoplastic resin-based composite material component independently preferably include one or more of carbon fiber, glass fiber, aramid fiber, PBO fiber, and basalt fiber. The present application does not particularly limit the fiber reinforcement method in the first fiber-reinforced thermoplastic resin-based composite material component and the second fiber-reinforced thermoplastic resin-based composite material component. Any fiber reinforcement method well known to those skilled in the art may be used, such as unidirectional / multidirectional plying, two-dimensional, or multi-dimensional forms.

[0043] In the present application, the reinforcing fibers used in the first fiber-reinforced thermoplastic resin-based composite material component and the second fiber-reinforced thermoplastic resin-based composite material component are preferably the same or different; the fiber reinforcement methods in the first fiber-reinforced thermoplastic resin-based composite material component and the second fiber-reinforced thermoplastic resin-based composite material component are preferably the same or different.

[0044] In the present application, the thermoplastic resins used in the first fiber-reinforced thermoplastic resin-based composite material component and the second fiber-reinforced thermoplastic resin-based composite material component independently preferably include one or more of PP, PC, ABS, PA, PPS, PEI, PEK, PEKK, PEEK, PEN, phthalein side-group-containing polyether ketone, phthalein side-group-containing polyether sulfone and polyaryl ether sulfone ketone containing naphthalene biphenyl structure.

[0045] After obtaining the first through hole and the second through hole, the present application overlaps the to-be-welded region of the first fiber-reinforced thermoplastic resin-based composite material component and the to-be-welded region of the second fiber-reinforced thermoplastic resin-based composite material component, so that the first through hole and the second through hole intersect. In the present application, the central axes of the first through hole and the second through hole preferably coincide.

[0046] In the present application, a hollow circular tube of a continuous fiber reinforced thermoplastic resin-based composite material is passed through the first through hole and the second through hole, and the two ends of the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material extend out of the outside of the first fiber reinforced thermoplastic resin-based composite material component and the second fiber reinforced thermoplastic resin-based composite material component, respectively, to obtain a connection part to be welded.

[0047] In the present application, the outer diameter of the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material is preferably less than or equal to the diameter of the first through hole and the second through hole; the difference between the diameter of the first through hole and the outer diameter of the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material is preferably within 1 mm; the difference between the diameter of the second through hole and the outer diameter of the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material is preferably within 1 mm.

[0048] In the present application, the ratio of the outer diameter to the wall thickness of the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube is preferably between 4.0 and 10.0. In the present application, the outer diameter of the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube is preferably between 4.0 and 16.0 mm; the wall thickness is preferably between 1.0 and 2.5 mm.

[0049] In the present application, the mass content of the fiber in the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material is preferably 35-70%, more preferably 55-65%. In the present application, the reinforcing fiber used in the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material preferably includes one or more of carbon fiber, glass fiber, aramid fiber, PBO fiber and basalt fiber; the thermoplastic resin used in the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material preferably includes one or more of PP, PC, ABS, PA, PPS, PEI, PEK, PEKK, PEEK, PEN, polyetherketone containing phthalide side groups, polyethersulfone containing phthalide side groups and polyarylethersulfoneketone containing naphthalene biphenyl structure.

[0050] In the present application, the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube is preferably prepared by a single-layer prepreg winding method, and the 0-degree fibers are arranged along the length direction of the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube.

[0051] In the present application, the thermoplastic resin used in the continuous fiber reinforced thermoplastic resin-based composite hollow tube is preferably the same as the thermoplastic resin used in the first fiber reinforced thermoplastic resin-based composite component and the thermoplastic resin used in the second fiber reinforced thermoplastic resin-based composite component. In a specific embodiment of the present application, the continuous fiber reinforced thermoplastic resin-based composite hollow tube and the first fiber reinforced thermoplastic resin-based composite component and the second fiber reinforced thermoplastic resin-based composite component are made of the same material.

[0052] The present application uses an ultrasonic welding head to crush the continuous fiber reinforced thermoplastic resin-based composite hollow tube extending out of the first fiber reinforced thermoplastic resin-based composite component and the second fiber reinforced thermoplastic resin-based composite component. Part of the resulting crushed material fills the hollow area of ​​the hollow tube, and the remaining resulting crushed material forms a fixed joint in the area to be welded of the first fiber reinforced thermoplastic resin-based composite component and the area to be welded of the second fiber reinforced thermoplastic resin-based composite component to obtain a molded connector.

[0053] In the present application, the welding frequency of the ultrasonic welding head is preferably 15-30 kHz, more preferably 20-25 kHz; the amplitude is preferably 20-40 μm, more preferably 30-40 μm; and the welding pressure is preferably 100-1000 N, more preferably 100-500 N.

[0054] In the present application, the fixing joint is preferably disc-shaped. In the present application, the fixing joint preferably comprises continuous fibers.

[0055] The present application adopts ultrasonic welding as the connection method. In the process of using the ultrasonic welding head to crush the continuous fiber reinforced thermoplastic resin-based composite hollow tube extending out of the first fiber reinforced thermoplastic resin-based composite component and the second fiber reinforced thermoplastic resin-based composite component, continuous pressure is applied to cause the continuous fiber reinforced thermoplastic resin-based composite hollow tube extending out of the first fiber reinforced thermoplastic resin-based composite component and the second fiber reinforced thermoplastic resin-based composite component to split and delaminate, and present a progressive collapse shape in both inward and outward directions until a disc-shaped fixed joint is formed with the first fiber reinforced thermoplastic resin-based composite component and the second fiber reinforced thermoplastic resin-based composite component.

[0056] In the present application, the portion of the resulting crushed material that fills the hollow region of the hollow tube refers to the portion of the crushed material that fills the hollow region of the hollow tube toward the interior of the hollow tube. In the present application, the crushed material toward the interior of the hollow tube is in the form of fragments (i.e., the fibers are broken, fractured, and shortened). In a specific embodiment of the present application, the crushed material toward the interior of the hollow tube is compacted within the interior of the hollow tube.

[0057] In the present application, the remaining crushed material forms a fixed joint in the area to be welded of the first fiber-reinforced thermoplastic resin-based composite material component and the area to be welded of the second fiber-reinforced thermoplastic resin-based composite material component, which means that the crushed material toward the outside of the hollow circular tube forms a fixed joint in the area to be welded of the first fiber-reinforced thermoplastic resin-based composite material component and the area to be welded of the second fiber-reinforced thermoplastic resin-based composite material component. In the present application, the crushed material toward the outside of the hollow circular tube remains in the form of continuous fibers.

[0058] In the present application, after the hollow area of ​​the hollow tube is completely filled and the fixed joint is formed, ultrasonic welding is preferably used to apply pressure to the interior of the hollow tube and / or the fixed joint; the pressure is preferably 100 to 1000 N, more preferably 100 to 500 N. The above steps in the present application can compact the material crushed toward the interior of the hollow tube within the hollow tube, thereby improving the flatness of the fixed joint.

[0059] In a specific embodiment of the present application, as shown in FIG1 , the connecting piece to be welded is placed on a base, the bottom end of the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material is inserted into the interior of the base, the second fiber reinforced thermoplastic resin-based composite material component is laid flat on the surface of the base, the first fiber reinforced thermoplastic resin-based composite material component is overlapped on the second fiber reinforced thermoplastic resin-based composite material component, and an ultrasonic welding head is used to crush the top end of the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material (as shown in (1) of FIG1 ), so that the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material extending out of the first fiber reinforced thermoplastic resin-based composite material component itself is split and layered, and presents a progressive collapse shape in both inward and outward directions, the crushed material toward the inside of the hollow circular tube fills the hollow area of ​​the hollow circular tube, and the crushed material toward the outside of the hollow circular tube forms a first disc-shaped fixed connection in the area to be welded of the first fiber reinforced thermoplastic resin-based composite material component. Head (as shown in (2) of Figure 1); then the obtained connection structure is turned upside down so that the first fiber reinforced thermoplastic resin-based composite material component is at the bottom and the second fiber reinforced thermoplastic resin-based composite material component is at the top, and an ultrasonic welding head is used to crush the end to be welded of the continuous fiber reinforced thermoplastic resin-based composite hollow tube (as shown in (3) of Figure 1), so that the continuous fiber reinforced thermoplastic resin-based composite hollow tube extending out of the second fiber reinforced thermoplastic resin-based composite material component itself appears to be split and layered, and presents a progressive collapse shape in both inward and outward directions, the crushed material inside the hollow tube fills the hollow area of ​​the hollow tube, and the crushed material outside the hollow tube forms a second disc-shaped fixed joint in the area to be welded of the second fiber reinforced thermoplastic resin-based composite material component (as shown in (4) of Figure 1); then an ultrasonic welding head is used to continuously apply pressure to the first disc-shaped fixed joint and the second disc-shaped fixed joint, and a molded connector is obtained after cooling.

[0060] The following will be combined with the embodiments of this application to clearly and completely describe the technical solutions in this application. Obviously, the embodiments described are only some of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0061] Example 1

[0062] Raw materials: unidirectional continuous carbon fiber reinforced polycarbonate (CF / PC) prepreg, fiber mass fraction is 55%, prepreg thickness is 0.18mm, molding temperature is 230℃.

[0063] The fiber-reinforced thermoplastic resin matrix composites are joined using the process shown in Figure 1:

[0064] S1: Laying the unidirectional CF / PC prepreg according to [0 / +45 / 90 / -45 / 02]s to prepare a first CF / PC composite material component 1 and a second CF / PC composite material component 2, wherein the thickness of the first CF / PC composite material component 1 and the second CF / PC composite material component 2 are both 2.17 mm;

[0065] S2: Performing hole processing on the to-be-welded area of ​​the first CF / PC composite material component 1 and the to-be-welded area of ​​the second CF / PC composite material component 2, respectively, to obtain a first through hole 11 and a second through hole 21; the diameter of the first through hole 11 is 10.50 mm; the diameter of the second through hole 21 is 10.50 mm;

[0066] S3: Using a cylindrical mold, the unidirectional CF / PC prepreg is wound to prepare a CF / PC composite hollow circular tube 3. The prepared hollow circular tube 3 has an outer diameter of 10.13 mm, an inner diameter of 7.42 mm, and a wall thickness of 1.36 mm.

[0067] S4: Overlapping the area to be welded of the first CF / PC composite material component 1 and the area to be welded of the second CF / PC composite material component 2, so that the first through hole 11 and the second through hole 21 are intersected, and the central axes of the first through hole 11 and the second through hole 21 coincide with each other;

[0068] The CF / PC composite hollow circular tube 3 is passed through the first through hole 11 and the second through hole 21 and connected to the first CF / PC composite component 1 and the second CF / PC composite component 2 to obtain a welded connection as shown in Figures 2 and 3; the length of the CF / PC composite hollow circular tube 3 extending from the first CF / PC composite component 1 is 6.58 mm; the length of the CF / PC composite hollow circular tube 3 extending from the second CF / PC composite component 2 is 8.00 mm;

[0069] The connecting piece to be welded is placed on the base, the bottom end of the CF / PC composite hollow circular tube 3 is deeply inserted into the base, and the second CF / PC composite material component 2 is laid flat on the surface of the base. The top end of the CF / PC composite hollow circular tube 3 is crushed by an ultrasonic welding head (as shown in (1) of Figure 1), so that the CF / PC composite hollow circular tube extending outside the first CF / PC composite material component 1 itself is split and layered, and presents a progressive collapse shape in both inward and outward directions. The crushed material inside the hollow circular tube fills the hollow area of ​​the hollow circular tube, and the crushed material outside the hollow circular tube forms a disc-shaped fixed joint in the area to be welded of the first CF / PC composite material component 1 (as shown in (2) of Figure 1). The welding frequency of the ultrasonic welding head is 20kHz, the amplitude is 40μm, the welding time is 2s, and the pressure is 100N.

[0070] The obtained connection structure is then turned upside down so that the first CF / PC composite material component 1 is at the bottom and the second CF / PC composite material component 2 is at the top. The ultrasonic welding head is used to crush the end of the CF / PC composite hollow circular tube 3 to be welded (as shown in (3) of Figure 1), so that the CF / PC composite hollow circular tube extending outside the second CF / PC composite material component 2 itself is split and layered, and presents a progressive collapse shape in both inward and outward directions. The crushed material inside the hollow circular tube fills the hollow area of ​​the hollow circular tube, and the crushed material outside the hollow circular tube forms a disc-shaped fixed joint in the area to be welded of the second CF / PC composite material component 2 (as shown in (4) of Figure 1). The welding frequency of the ultrasonic welding head is 20kHz, the amplitude is 40μm, the welding time is 2.5s, and the pressure is 100N.

[0071] Then, the ultrasonic welding head was vibrated on both sides of the hollow circular tube for 1.5 seconds at a pressure of 500N, and a molded connecting part was obtained after cooling.

[0072] The extrusion load of the molded connector prepared in this embodiment is 6293.45N.

[0073] Example 2

[0074] Raw materials: unidirectional continuous carbon fiber reinforced polycarbonate (CF / PC) prepreg, fiber mass fraction is 55%, prepreg thickness is 0.18mm, molding temperature is 230℃.

[0075] The fiber-reinforced thermoplastic resin matrix composites are joined using the process shown in Figure 1:

[0076] S1: Laying the unidirectional CF / PC prepreg according to [0 / +45 / 90 / -45 / 02]s to prepare a first CF / PC composite material component 1 and a second CF / PC composite material component 2, wherein the thickness of the first CF / PC composite material component 1 and the second CF / PC composite material component 2 are both 2.20 mm;

[0077] S2: Performing hole processing on the to-be-welded area of ​​the first CF / PC composite material component 1 and the to-be-welded area of ​​the second CF / PC composite material component 2, respectively, to obtain a first through hole 11 and a second through hole 21; the diameter of the first through hole 11 is 10.50 mm; the diameter of the second through hole 21 is 10.50 mm;

[0078] S3: Using a cylindrical mold, the unidirectional CF / PC prepreg is wound to prepare a CF / PC composite hollow circular tube 3. The prepared hollow circular tube 3 has an outer diameter of 10.15 mm, an inner diameter of 7.46 mm, and a wall thickness of 1.35 mm.

[0079] S4: Overlapping the area to be welded of the first CF / PC composite material component 1 and the area to be welded of the second CF / PC composite material component 2, so that the first through hole 11 and the second through hole 21 are intersected, and the central axes of the first through hole 11 and the second through hole 21 coincide with each other;

[0080] The CF / PC composite hollow circular tube 3 is passed through the first through hole 11 and the second through hole 21 and connected to the first CF / PC composite component 1 and the second CF / PC composite component 2 to obtain a welded connection as shown in Figures 2 and 3; the length of the CF / PC composite hollow circular tube 3 extending from the first CF / PC composite component 1 is 8.48 mm; the length of the CF / PC composite hollow circular tube 3 extending from the second CF / PC composite component 2 is 8.00 mm;

[0081] The connecting piece to be welded is placed on the base, the bottom end of the CF / PC composite hollow circular tube 3 is deeply inserted into the base, and the second CF / PC composite component 2 is laid flat on the surface of the base. The top end of the CF / PC composite hollow circular tube 3 is crushed by an ultrasonic welding head (as shown in (1) of FIG. 1 ), so that the CF / PC composite hollow circular tube extending outside the first CF / PC composite component 1 itself is split and layered, and presents a progressive collapse shape in both inward and outward directions. The crushed material inside the hollow circular tube fills the hollow area of ​​the hollow circular tube, and the crushed material outside the hollow circular tube forms a disc-shaped fixed joint in the area to be welded of the first CF / PC composite component 1 (as shown in (2) of FIG. 1 ). The welding frequency of the ultrasonic welding head is 20 kHz, the amplitude is 40 μm, the welding time is 2 s, and the pressure is 100 N.

[0082] Then, the obtained connection structure is turned upside down so that the first CF / PC composite material component 1 is at the bottom and the second CF / PC composite material component 2 is at the top. The ultrasonic welding head is used to crush the end of the CF / PC composite hollow circular tube 3 to be welded (as shown in (3) of Figure 1), so that the CF / PC composite hollow circular tube extending outside the second CF / PC composite material component 2 itself is split and layered, and presents a progressive collapse shape in both inward and outward directions. The crushed material inside the hollow circular tube fills the hollow area of ​​the hollow circular tube, and the crushed material outside the hollow circular tube forms a disc-shaped fixed joint in the area to be welded of the second CF / PC composite material component 2 (as shown in (4) of Figure 1). The welding frequency of the ultrasonic welding head is 20 kHz, the amplitude is 40 μm, the welding time is 2.75 s, and the pressure is 100 N.

[0083] Then, the ultrasonic welding head was vibrated on both sides of the hollow circular tube for 1.5 seconds at a pressure of 700N, and a molded connecting part was obtained after cooling.

[0084] The molded connector prepared in this embodiment did not fail under a pull-pull cyclic load with a maximum load of 1800 N, a stress ratio R=0.1, and a cycle number of 1 million times.

[0085] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for connecting continuous fiber reinforced thermoplastic resin-based composite materials, characterized in that: The following steps are involved: Arranging a first through hole in the to-be-welded region of the first fiber-reinforced thermoplastic resin-based composite material component; providing a second through hole in the to-be-welded region of the second fiber-reinforced thermoplastic resin-based composite material component; Overlapping the to-be-welded region of the first fiber-reinforced thermoplastic resin-based composite material component and the to-be-welded region of the second fiber-reinforced thermoplastic resin-based composite material component, so that the first through hole and the second through hole are interconnected; Passing a continuous fiber reinforced thermoplastic resin-based composite hollow circular tube through the first through hole and the second through hole, with both ends of the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube extending out of the first fiber reinforced thermoplastic resin-based composite component and the second fiber reinforced thermoplastic resin-based composite component, respectively, to obtain a connection piece to be welded; An ultrasonic welding head is used to crush the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material extending out of the first fiber reinforced thermoplastic resin-based composite material component and the second fiber reinforced thermoplastic resin-based composite material component, and part of the crushed material obtained fills the hollow area of ​​the hollow circular tube, and the remaining crushed material forms a fixed joint in the area to be welded of the first fiber reinforced thermoplastic resin-based composite material component and the area to be welded of the second fiber reinforced thermoplastic resin-based composite material component to obtain a molded connector.

2. The connection method according to claim 1, characterized in that: The first through hole and the second through hole have the same diameter.

3. The connection method according to claim 1 or 2, characterized in that: The central axes of the first through hole and the second through hole coincide with each other.

4. The connection method according to claim 1, characterized in that: The ratio of the outer diameter to the wall thickness of the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube is between 4.0 and 10.

0.

5. The connection method according to claim 1, characterized in that: The mass content of the fibers in the continuous fiber reinforced thermoplastic resin-based composite hollow tube is 35-70%.

6. The connection method according to claim 1 or 5, characterized in that: The fibers used in the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube include one or more of carbon fiber, glass fiber, aramid fiber, PBO fiber and basalt fiber.

7. The connection method according to claim 1 or 5, characterized in that: The thermoplastic resin used in the hollow circular tube of the continuous fiber reinforced thermoplastic resin-based composite material includes one or more of PP, PC, ABS, PA, PPS, PEI, PEK, PEKK, PEEK, PEN, polyether ketone containing phthalide side groups, polyether sulfone containing phthalide side groups and polyarylethersulfoneketone containing phthalide structure.

8. The connection method according to claim 1, characterized in that: The continuous fiber reinforced thermoplastic resin-based composite hollow circular tube is prepared by a single-layer prepreg winding method, and the 0-degree fibers are arranged along the length direction of the continuous fiber reinforced thermoplastic resin-based composite hollow circular tube.

9. The connection method according to claim 1, characterized in that: The thermoplastic resin used in the first fiber-reinforced thermoplastic resin-based composite material component and the thermoplastic resin used in the second fiber-reinforced thermoplastic resin-based composite material component are the same.

10. The connection method according to claim 1 or 9, characterized in that: The thermoplastic resins used in the first fiber-reinforced thermoplastic resin-based composite material component and the second fiber-reinforced thermoplastic resin-based composite material component independently include one or more of PP, PC, ABS, PA, PPS, PEI, PEK, PEKK, PEEK, PEN, phthalide-containing polyether ketone, phthalide-containing polyether sulfone and polyarylethersulfoneketone containing a naphthalenyl structure.

11. The connection method according to claim 1 or 9, characterized in that: The reinforcing fibers used in the first fiber-reinforced thermoplastic resin-based composite material component and the second fiber-reinforced thermoplastic resin-based composite material component independently include one or more of carbon fiber, glass fiber, aramid fiber, PBO fiber and basalt fiber.

12. The connection method according to claim 1 or 9, characterized in that: The thermoplastic resin used in the continuous fiber reinforced thermoplastic resin-based composite hollow tube is the same as the thermoplastic resin used in the first fiber reinforced thermoplastic resin-based composite component and the thermoplastic resin used in the second fiber reinforced thermoplastic resin-based composite component.

13. The connection method according to claim 1, characterized in that: The fixed joint is disc-shaped.

14. The connection method according to claim 1 or 13, characterized in that: The fixed joint comprises continuous fibers.

15. The connection method according to claim 1, characterized in that: The welding frequency of the ultrasonic welding head is 15-30kHz, the amplitude is 20-40μm, and the welding pressure is 100-1000N.

16. A molded connection part obtained by the connection method according to any one of claims 1 to 15, comprising a first fiber-reinforced thermoplastic resin-based composite material component and a second fiber-reinforced thermoplastic resin-based composite material component overlapped; The to-be-welded region of the first fiber-reinforced thermoplastic resin-based composite material component is provided with a first through hole; The area to be welded of the second fiber-reinforced thermoplastic resin-based composite material component is provided with a second through hole; The first through hole and the second through hole are interconnected; A continuous fiber reinforced thermoplastic resin-based composite hollow tube is passed through the first through hole and the second through hole; the interior of the continuous fiber reinforced thermoplastic resin-based composite hollow tube is filled with crushed material in the form of fragments; The outer ends of the first through hole and the second through hole are covered with a fixing joint; the material of the fixing joint is a continuous fiber reinforced thermoplastic resin-based composite material.

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