Preformed hole type Z-pin implantation method with protection

Abstract

The invention discloses a prefabricated hole type Z-pin implanting method with protection, and belongs to the technical field of composite material Z-pins, and the method comprises the following steps: placing continuous Z-pins in an implanting head, penetrating through a roller group of the implanting head, a guide pipe and a hollow thin-wall steel needle, controlling the implanting head, enabling the hollow thin-wall steel needle to pierce a composite material structure, and rising, the continuous Z-pin discretization and the effective residence of the discrete Z-pin in the composite material structure are realized through the cooperation of the roller group and the auxiliary cutter, and Z-pin implantation is completed. According to the method, the Z-pin can be effectively protected in the implanting process, the implanting path of the Z-pin is guaranteed, discrete Z-pin with the specific length does not need to be prepared in advance, a foam prefabricated body does not need to be prepared, the application range of the Z-pin strengthening process is expanded, meanwhile, the implanting efficiency of the Z-pin is greatly improved, and practicability is good.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material Z-pins, and in particular relates to a method for implanting a protected prefabricated hole type Z-pin. Background Art

[0002] Laminated composite materials have poor interlayer performance and are prone to delamination damage, so researchers have developed a variety of interlayer strengthening methods. Z-pin strengthening has attracted widespread attention due to its low cost, easy operation, and significant toughening effect. At present, there are two main common Z-pin implantation processes, namely ultrasonic implantation and prefabricated hole implantation. The former uses a metal hammer head to vibrate at a certain frequency (20-30kHz) and amplitude (20-30μm), continuously hammering the rear end of the cut Z-pin, thereby "knocking" the Z-pin into the workpiece; the main principle of the latter is to use a solid steel needle to pierce a prefabricated hole at the target implantation position, and then insert the cut Z-pin into it.

[0003] However, the application of Z-pin reinforcement is currently limited to a small range of universities, laboratories and related research institutes, and has hardly been put into engineering applications. Fundamentally, the traditional Z-pin implantation process has three major bottleneck problems: 1) Since Z-pins are usually prepared using a pultrusion process and are not fully cured, their strength and bending stiffness are low. Therefore, during the use of the ultrasonic implantation process (especially for thick prepregs), it is easy for the Z-pin implantation position to deviate from the predetermined path and the front end to split. 2) The ultrasonic implantation process requires the use of a foam preform, and the preparation of the foam preform is often done manually. Since the Z-pin spacing is small (3 to 8 mm), the workload is huge when facing large-size workpieces; in addition, the foam preform is usually based on hard foam. When strengthening curved workpieces, the two are difficult to fit together, so the use scenarios are often limited to flat workpieces. 3) Similar to the ultrasonic implantation process, the prefabricated hole implantation process also requires the preparation of discrete Z-pins in advance. The entire process is equally labor-intensive without the assistance of automated equipment. In addition, the prefabricated hole will shrink to a certain extent after the steel needle is pulled out. Therefore, the diameter of the steel needle often needs to be 1.5 times or more of the diameter of the Z-pin to ensure that the Z-pin can be smoothly placed in the prefabricated hole, which will have a greater negative impact on the in-plane performance of the composite material.

[0004] After consulting a large amount of relevant technical information, it was found that the current domestic Z-pin implantation method cannot meet the actual engineering application needs. Therefore, if some innovations can be introduced on the basis of the existing Z-pin implantation method, so that Z-pin can meet the premise of efficient implantation of composite material structure and greatly improve the comprehensive performance of composite material structure, it will be of great significance for the large-scale application of composite materials in various fields. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a protected prefabricated hole Z-pin implantation method, which can solve the following technical problems: the problem that discrete Z-pins and foam preforms need to be prepared in advance before Z-pin implantation; the problem that the Z-pin is prone to deviate from the planned penetration path and split at the front end due to its own insufficient bending stiffness and strength during the implantation process; the problem that it is difficult to Z-pin strengthen the curved composite material structure; and the problem that it is difficult to achieve automated continuous Z-pin implantation.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a method for implanting a protected prefabricated hole Z-pin, comprising the following steps:

[0007] S1: Place the continuous Z-pin in the implant head, pass through the roller assembly, catheter and hollow thin-walled steel needle of the implant head, and make the front end of the continuous Z-pin flush with the front end of the hollow thin-walled steel needle;

[0008] S2: Control the implant head so that the hollow thin-walled steel needle of the implant head pierces the composite material structure and rises so that the front end of the hollow thin-walled steel needle retreats into the interior of the composite material structure. At the same time, control the roller assembly of the implant head to lock so that the continuous Z-pin and the hollow thin-walled steel needle remain relatively still.

[0009] S3: Control the implant head so that the hollow thin-walled steel needle of the implant head is withdrawn from the interior of the composite material structure, and at the same time, control the roller group of the implant head to rotate so that the continuous Z-pin and the composite material structure remain relatively still;

[0010] S4: Using an auxiliary tool to cut the continuous Z-pin between the front end of the hollow thin-walled steel needle and the surface of the composite structure, a discrete Z-pin residing in the composite structure is obtained;

[0011] S5: controlling the roller assembly of the implant head to rotate, retracting the continuous Z-pin exposed at the front end of the hollow thin-walled steel needle, and controlling the implant head to push the discrete Z-pin exposed on the surface of the composite material structure into the composite material structure;

[0012] S6: Replace the implant head to penetrate the spatial position of the composite structure, and repeat S2 to S5 to perform continuous Z-pin implantation on the composite structure.

[0013] The beneficial effects of the present invention are as follows: the present invention places a continuous Z-pin inside a hollow thin-walled steel needle, and inserts the two together into a composite material structure, and realizes the discretization of the continuous Z-pin and the effective retention of the discrete Z-pin in the composite material structure through the cooperation of a roller group and an auxiliary tool; the overall strength and bending stiffness of the Z-pin-containing implant are improved through the hollow thin-walled steel needle, so that the Z-pin is well protected during the entire implantation process, avoiding the front end splitting of the Z-pin, and effectively ensuring the implantation path of the Z-pin. At the same time, the present invention uses an auxiliary tool to cut the Z-pin after implanting a continuous Z-pin of a suitable length, without the need to prepare discrete Z-pins of a specific length in advance, and even more without the need to prepare a foam preform; by adjusting the angle of the implant head, the present invention can smoothly realize the Z-pin implantation of a curved workpiece. This new prefabricated hole Z-pin implantation process not only retains the advantages of the traditional prefabricated hole Z-pin implantation process, such as large Z-pin implantation thickness and little impact on Z-pin integrity, but also greatly expands the application scope of the Z-pin strengthening process, while greatly improving the Z-pin implantation efficiency and having good practicality.

[0014] Furthermore: the roller group is used to control the movement of the continuous Z-pin in the catheter and the hollow thin-walled steel needle by rotation, the inner diameter of the catheter is larger than the diameter of the continuous Z-pin; the inner diameter of the hollow thin-walled steel needle is equal to the diameter of the continuous Z-pin.

[0015] The beneficial effect of the above further scheme is that the continuous Z-pin in the implant head can be controlled by the roller group, the catheter and the hollow thin-walled steel needle to ensure that the continuous Z-pin can smoothly enter the interior of the composite material structure.

[0016] Further: the specific steps of S2 are as follows:

[0017] S201: Control the spatial orientation of the implant head so that the implant head reaches a specified position and posture;

[0018] S202: Control the implant head to descend so that the hollow thin-walled steel needle of the implant head and the continuous Z-pin pierce the composite material structure together;

[0019] S203: When S202 is being performed, the roller assembly of the implant head locks the continuous Z-pin, so that the relative position of the continuous Z-pin and the hollow thin-walled steel needle remains unchanged;

[0020] S204: Control the implant head to rise, so that the front end of the hollow thin-walled steel needle of the implant head and the continuous Z-pin are withdrawn into the composite material structure together;

[0021] S205: When S204 is being performed, the roller assembly of the implant head locks the continuous Z-pin so that the relative position of the continuous Z-pin and the hollow thin-walled steel needle remains unchanged.

[0022] The beneficial effect of the above further scheme is that through the hollow thin-walled steel needle and the roller group, the continuous Z-pin can be implanted into the composite material structure completely without bending, thereby improving the quality of the implanted Z-pin.

[0023] Further: the specific steps of S5 are as follows:

[0024] S501: Control the roller assembly of the implant head to rotate, retract the continuous Z-pin that exposes the front end of the hollow thin-walled steel needle, and make the front end of the continuous Z-pin flush with the front end of the hollow thin-walled steel needle;

[0025] S502: Controlling the roller assembly of the implant head to lock tightly, so that the relative positions of the continuous Z-pin and the hollow thin-walled steel needle remain unchanged;

[0026] S503: Control the implant head to descend, and use the continuous Z-pin and the hollow thin-walled steel needle to push the discrete Z-pin exposed on the surface of the composite material structure into the composite material structure.

[0027] The beneficial effect of the above further scheme is that by locking the continuous Z-pins through the roller group, the Z-pins that extend beyond the surface of the composite material structure can be pressed into the composite material structure, and the length of the Z-pins residing in the composite material structure can be accurately controlled.

[0028] Furthermore: the discrete Z-pin residing in the composite material structure has a length that is a set threshold value of the thickness of the composite material structure at the implantation position.

[0029] The beneficial effects of the above further solution are: ensuring the implantation thickness of the Z-pin in the composite material structure and ensuring that the Z-pin does not protrude after the composite material is cured. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A method for implanting a protected prefabricated hole Z-pin according to the present invention;

[0031] Figure 2 is a schematic diagram of a hollow thin-walled steel needle in the present invention;

[0032] Figure 3 It is a cross-sectional schematic diagram of the entire implant head without continuous Z-pin in the present invention;

[0033] Figure 4 It is a cross-sectional schematic diagram of the implant head integrally piercing the composite material structure in the case of continuous Z-pin in the present invention;

[0034] Figure 5 It is a cross-sectional schematic diagram of the present invention in which the implant head is completely withdrawn from the composite material structure under the condition of containing the continuous Z-pin, and the continuous Z-pin is retained in the composite material structure;

[0035] Figure 6 is a cross-sectional schematic diagram of a discrete Z-pin residing in a composite material structure in the present invention;

[0036] Among them, 1. continuous Z-pin, 2. roller set, 3. catheter, 4. hollow thin-walled steel needle, 5. composite material structure, 6. thick connecting rod, 7. auxiliary tool, 8. discrete Z-pin. DETAILED DESCRIPTION

[0037] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0038] Z-pin strengthening is a technology used to enhance the interlaminar performance of composite materials. It mainly inserts small metal or non-metallic rods (called Z-pins) into uncured composite materials to improve their interlaminar fracture toughness and shear strength. The material of Z-pin can be metal (such as stainless steel, aluminum alloy, titanium alloy, etc.) or non-metal (such as carbon fiber, glass fiber, Kevlar, etc.), and its diameter is usually between 0.2mm and 1.0mm, and the most commonly used diameters are 0.3mm and 0.5mm.

[0039] like Figure 2 As shown, it is a schematic diagram of the hollow thin-walled steel needle of the present invention; Figure 3 As shown in FIG. 1 , it is a cross-sectional schematic diagram of the entire implant head without continuous Z-pin in the present invention; Figure 4 As shown in FIG. 1 , it is a cross-sectional schematic diagram of the implant head integrally piercing the composite material structure under the condition of continuous Z-pin in the present invention; Figure 5 As shown in FIG. 1 , it is a cross-sectional schematic diagram of the present invention in which the implant head is completely withdrawn from the composite material structure under the condition of containing continuous Z-pins, and the continuous Z-pins are retained in the composite material structure; Figure 6 FIG. 1 is a cross-sectional view of a discrete Z-pin residing in a composite material structure in the present invention; Figures 2 to 6, a protected prefabricated hole Z-pin implantation method of the present invention is described.

[0040] like Figure 1 As shown, a method for implanting a protected prefabricated hole Z-pin according to the present invention comprises the following steps:

[0041] S1: Place the continuous Z-pin 1 in the implant head, pass through the roller set 2, catheter 3 and hollow thin-walled steel needle 4 of the implant head, and make the front end of the continuous Z-pin 1 flush with the front end of the hollow thin-walled steel needle 4;

[0042] In one embodiment of the present invention, the roller group 2 can control the movement of the Z-pin 1 in the catheter 3 and the hollow thin-walled steel needle 4 by rotating and locking; the inner diameter of the catheter 3 is larger than the diameter of the continuous Z-pin 1; the inner diameter of the hollow thin-walled steel needle 4 is the same as the diameter of the continuous Z-pin 1, the hollow thin-walled steel needle 4 is removable and replaceable, and the wall thickness of the hollow thin-walled steel needle 4 is ≤0.15mm.

[0043] S2: Control the implant head so that the hollow thin-walled steel needle 4 of the implant head pierces the composite material structure 5 and rises so that the front end of the hollow thin-walled steel needle 4 retreats into the interior of the composite material structure 5. At the same time, control the roller group 2 of the implant head to lock so that the continuous Z-pin 1 and the hollow thin-walled steel needle 4 remain relatively still;

[0044] In one embodiment of the present invention, the implant head is mounted on a mechanical arm, and the spatial orientation of the implant head is adjusted by controlling the movement of the mechanical arm;

[0045] The specific steps of S2 are as follows:

[0046] S201: Control the spatial orientation of the implant head so that the implant head reaches a specified position and posture;

[0047] S202: Control the implant head to descend, so that the hollow thin-walled steel needle 4 of the implant head and the continuous Z-pin 1 pierce the composite material structure 5 together;

[0048] S203: When S202 is performed, the roller assembly 2 of the implant head locks the continuous Z-pin 1, so that the relative position of the continuous Z-pin 1 and the hollow thin-walled steel needle 4 remains unchanged;

[0049] S204: Control the implant head to rise, so that the front end of the hollow thin-walled steel needle 4 of the implant head and the continuous Z-pin 1 are withdrawn into the composite material structure 5 together;

[0050] S205: When S204 is being performed, the roller assembly 2 of the implant head locks the continuous Z-pin 1, so that the relative position of the continuous Z-pin 1 and the hollow thin-walled steel needle 4 remains unchanged.

[0051] S3: Control the implant head to make the hollow thin-walled steel needle 4 of the implant head withdraw from the interior of the composite material structure 5, and at the same time, control the roller group 2 of the implant head to rotate so that the continuous Z-pin 1 and the composite material structure 5 remain relatively still;

[0052] S4: using the auxiliary tool 7 to cut the continuous Z-pin 1 between the front end of the hollow thin-walled steel needle 4 and the surface of the composite material structure 5 to obtain a discrete Z-pin 8 residing in the composite material structure 5;

[0053] In one embodiment of the present invention, the length of the discrete Z-pin 8 finally residing in the composite material structure is a set threshold value of the thickness of the composite material structure 5 at the implantation position, which can be set to 90% to 95%.

[0054] S5: Control the roller group 2 of the implant head to rotate, retract the continuous Z-pin 1 exposed at the front end of the hollow thin-walled steel needle 4, and control the implant head to push the discrete Z-pin 8 exposed on the surface of the composite material structure 5 into the composite material structure 5, so as to complete the Z-pin implantation at the current puncture position of the composite material structure;

[0055] The specific steps of S5 are as follows:

[0056] S501: Control the roller group 2 of the implant head to rotate, retract the continuous Z-pin 1 that exposes the front end of the hollow thin-walled steel needle 4, and make the front end of the continuous Z-pin 1 flush with the front end of the hollow thin-walled steel needle 4;

[0057] S502: Controlling the roller assembly 2 of the implant head to be locked, so that the relative positions of the continuous Z-pin 1 and the hollow thin-walled steel needle 4 remain unchanged;

[0058] S503: Control the implantation head to descend, and use the continuous Z-pin 1 and the hollow thin-walled steel needle 4 to push the discrete Z-pin 8 exposed on the surface of the composite material structure 5 into the composite material structure 5, so as to complete the Z-pin implantation at the current puncture position of the composite material structure.

[0059] S6: Replace the implant head to penetrate the spatial position of the composite material structure 5, and repeat S2 to S5 to perform continuous Z-pin implantation on the composite material structure 5.

[0060] The beneficial effects of the present invention are as follows: the present invention places a continuous Z-pin inside a hollow thin-walled steel needle, and inserts the two together into a composite material structure, and realizes the discretization of the continuous Z-pin and the effective retention of the discrete Z-pin in the composite material structure through the cooperation of a roller group and an auxiliary tool; through the hollow thin-walled steel needle, the overall strength and bending stiffness of the Z-pin-containing implant are improved, so that the Z-pin is well protected during the entire implantation process, and the front end of the Z-pin is avoided from splitting, while the implantation path of the Z-pin is effectively guaranteed. At the same time, the present invention uses an auxiliary tool to cut the Z-pin after implanting a continuous Z-pin of a suitable length, without the need to prepare a discrete Z-pin of a specific length in advance, and even more without the need to prepare a foam preform; by adjusting the angle of the implant head, the present invention can smoothly realize the Z-pin implantation of a curved workpiece. This new prefabricated hole implantation process not only retains the advantages of large implantation thickness and small impact on the in-plane performance of the composite material structure in the traditional prefabricated hole implantation process, but also greatly expands the application scope of the Z-pin strengthening process, while greatly improving the implantation efficiency of the Z-pin, and has good practicality.

Claims

1. A method for implanting a protected prefabricated hole Z-pin, characterized in that: The following steps are involved: S1: Place the continuous Z-pin (1) in the implant head, pass it through the roller assembly (2), catheter (3) and hollow thin-walled steel needle (4) of the implant head, and make the front end of the continuous Z-pin (1) flush with the front end of the hollow thin-walled steel needle (4); S2: Control the implant head so that the hollow thin-walled steel needle (4) of the implant head pierces the composite material structure (5) and rises so that the front end of the hollow thin-walled steel needle (4) retreats into the interior of the composite material structure (5). At the same time, control the roller assembly (2) of the implant head to lock tightly so that the continuous Z-pin (1) and the hollow thin-walled steel needle (4) remain relatively still; S3: Controlling the implant head so that the hollow thin-walled steel needle (4) of the implant head is withdrawn from the interior of the composite material structure (5), and at the same time, controlling the roller group (2) of the implant head to rotate so that the continuous Z-pin (1) and the composite material structure (5) remain relatively still; S4: using an auxiliary tool (7) to cut the continuous Z-pin (1) between the front end of the hollow thin-walled steel needle (4) and the surface of the composite material structure (5) to obtain a discrete Z-pin (8) residing in the composite material structure (5); S5: Controlling the roller assembly (2) of the implant head to rotate, retracting the continuous Z-pin (1) exposed at the front end of the hollow thin-walled steel needle (4), and controlling the implant head to push the discrete Z-pin (8) exposed at the surface of the composite material structure (5) into the composite material structure (5); S6: Replace the implant head to penetrate the spatial position of the composite material structure (5), and repeat S2 to S5 to perform continuous Z-pin implantation on the composite material structure (5).

2. The method for implanting a protected prefabricated Z-pin according to claim 1, characterized in that: The roller assembly (2) is used to control the movement of the continuous Z-pin (1) in the catheter (3) and the hollow thin-walled steel needle (4) by rotation, wherein the inner diameter of the catheter (3) is larger than the diameter of the continuous Z-pin (1); and the inner diameter of the hollow thin-walled steel needle (4) is equal to the diameter of the continuous Z-pin (1).

3. The method for implanting a protected prefabricated Z-pin according to claim 1, characterized in that: The specific steps of S2 are as follows: S201: Control the spatial orientation of the implant head so that the implant head reaches a specified position and posture; S202: Control the implant head to descend, so that the hollow thin-walled steel needle (4) of the implant head and the continuous Z-pin (1) pierce the composite material structure (5) together; S203: When S202 is being performed, the roller assembly (2) of the implant head locks the continuous Z-pin (1) so that the relative position of the continuous Z-pin (1) and the hollow thin-walled steel needle (4) remains unchanged; S204: Control the implant head to rise, so that the front end of the hollow thin-walled steel needle (4) of the implant head and the continuous Z-pin (1) are retracted into the composite material structure (5); S205: When S204 is being performed, the roller assembly (2) of the implant head locks the continuous Z-pin (1) so that the relative position of the continuous Z-pin (1) and the hollow thin-walled steel needle (4) remains unchanged.

4. The method for implanting a protected prefabricated Z-pin according to claim 1, characterized in that: The specific steps of S5 are as follows: S501: Controlling the roller assembly (2) of the implant head to rotate, retracting the continuous Z-pin (1) that is exposed from the front end of the hollow thin-walled steel needle (4), so that the front end of the continuous Z-pin (1) is flush with the front end of the hollow thin-walled steel needle (4); S502: Controlling the roller assembly (2) of the implant head to lock tightly, so that the relative positions of the continuous Z-pin (1) and the hollow thin-walled steel needle (4) remain unchanged; S503: Control the implant head to descend, and use the continuous Z-pin (1) and the hollow thin-walled steel needle (4) to push the discrete Z-pin (8) exposed on the surface of the composite material structure (5) into the composite material structure (5).

5. The method for implanting a protected prefabricated Z-pin according to claim 1, characterized in that: The discrete Z-pins (8) residing in the composite material structure have a length equal to a set threshold value of the thickness of the composite material structure (5) at the implantation position.

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