A maze-type interlocking intelligent structure based on 4D printing and its locking method

Abstract

The present invention discloses a labyrinth-type interlocking intelligent structure based on 4D printing and a locking method thereof. One end of the long non-executing segment of the interlocking intelligent structure is fixed on the connecting piece, and the locking actuator and the short non-executing segment are arranged alternately in sequence and connected end to end to form a locking segment, and the locking segment is connected to the other end of the long non-executing segment through the locking actuator at one end. The method comprises: placing two labyrinth-type interlocking intelligent structures between two parts to be connected in opposite directions according to the same chirality; bending and deforming the locking actuator to form a labyrinth-type interlocking state through external field stimulation; removing the external field stimulation, and the locking actuator recovering its strength, and finally locking the two parts to be connected. The labyrinth-type interlocking intelligent structure obtained by the present invention has the advantages of simple structure, self-drive, light weight, no pollution, reliable interlocking, etc., and responds instantly to thermal stimulation, and can achieve reliable locking of the parts to be connected without applying external force.

Description

Technical Field

[0001] The present invention relates to a maze-type interlocking intelligent structure and the field of additive manufacturing, and in particular to a maze-type interlocking intelligent structure based on 4D printing and a locking method thereof. Background Art

[0002] Locking connection devices are widely used in underwater docking, aerospace, automobile manufacturing, construction engineering and other fields. Reliable locking devices are a key part to ensure the stable operation of mechanical systems. The locking connection devices commonly used in traditional mechanical engineering usually require complex mechanical structure design, the combination and selection of multiple parts, and the mechanical participation of humans and machines, such as bolt and nut connection devices, welding devices, riveting devices, etc., which have poor environmental adaptability and cannot achieve intelligent and controllable locking of the mechanism. Therefore, there is a need for a programmable, controllable deformation, and reliable interlocking intelligent locking device. Summary of the Invention

[0003] To address the problems in the prior art, the present invention provides a 4D-printed labyrinth-like interlocking intelligent structure and its locking method. The product of the present invention responds instantly to external temperature stimuli and, without the need for external force, forms a labyrinth-like interlocking mechanism based on action execution priority, reliably locking the connected parts.

[0004] The technical solution adopted in the present invention is:

[0005] 1. A maze-like interlocking intelligent structure based on 4D printing:

[0006] The labyrinthine interlocking intelligent structure consists of a long non-actuating segment, several locking actuators, and several short non-actuating segments. One end of the long non-actuating segment is fixed to a connector. The locking actuators and short non-actuating segments are arranged alternately and connected end to end to form a locking segment. The locking segment is terminated by a locking actuator and a short non-actuating segment, respectively. The locking segment is connected to the other end of the long non-actuating segment via a locking actuator at one end. The locking actuator performs bending deformation, while the non-actuating segments connect the locking actuators, forming an undeformed intelligent structure.

[0007] The locking actuator includes an active layer and a passive layer arranged in a stacked manner, and the active layer of each locking actuator is located on the same side of the maze-type interlocking intelligent structure; the active layer is composed of a plurality of stacked printed layers, each of which includes a plurality of parallel printing paths and is parallel to the length direction of the locking section; the passive layer is composed of a plurality of stacked mesh printed layers, each of which includes a plurality of crossed printing paths and forms an angle of 45° and -45° with the length direction of the locking section.

[0008] The ratio k of the thickness of the passive layer and the active layer of each locking actuator is different; the side dimensions connecting the active layer and the passive layer of the locking actuator are the same, and the side dimensions connecting the locking actuator and the long non-executing section and the short non-executing section are the same.

[0009] The long non-executable section and the short non-executable section are both composed of a plurality of mesh-shaped printed layers stacked together, each mesh-shaped printed layer including a plurality of intersecting printing paths and forming angles of 45° and -45° with the length direction of the locking section.

[0010] The long non-executing section, the short non-executing section and each locking actuator are all made of shape memory polymer material.

[0011] 2. A locking method for a maze-type interlocking intelligent structure:

[0012] The method comprises the following steps:

[0013] Step 1: Place two labyrinth-type interlocking intelligent structures between two oppositely spaced parts to be connected in opposite directions according to the same chirality. The fixed end of one end of each labyrinth-type interlocking intelligent structure is connected to one of its own parts to be connected, and the other end of each labyrinth-type interlocking intelligent structure is a free end and does not contact the other part to be connected; the opposite side of the locking actuator of the two labyrinth-type interlocking intelligent structures is the side where the active layer is located; in the initial state, the two labyrinth-type interlocking intelligent structures are in a straight line state and are arranged in parallel and spaced apart.

[0014] Step 2: Through external field stimulation, each locking actuator of each maze-like interlocking intelligent structure is bent and deformed toward the other maze-like interlocking intelligent structure at the same time, driving the two maze-like interlocking intelligent structures to deform from their respective free ends to the fixed ends with the same deformation scale, thereby forming a maze-like interlocking state.

[0015] Step 3: Remove the external field stimulation, and the strength of each locking actuator is restored to the strength of the initial state, so that the two parts to be connected are finally locked.

[0016] In the step 2, the external field stimulation is specifically temperature stimulation, and the temperature stimulation is specifically 80-90° C., which is 20-30° C. higher than the glass transition temperature of the shape memory polymer.

[0017] In the step 2, during the deformation process of the labyrinth interlocking intelligent structure, each locking actuator is bent and deformed according to its own preset action execution priority, and every two adjacent non-executing segments are perpendicular to each other in the labyrinth interlocking state.

[0018] The action execution priorities of the locking actuators from the free end to the fixed end of the maze-type interlocking intelligent structure are arranged in order from high to low. The higher the action execution priority, the smaller the thickness ratio k between the passive layer and the active layer of the locking actuator and the shorter the action execution completion time during bending. The number of action execution priorities is the same as the number of locking actuators in each maze-type interlocking intelligent structure.

[0019] The action execution priority is specifically divided into three or five priorities: the first priority G1, the second priority G2, the third priority G3, the fourth priority G4 and the fifth priority G5 correspond to the thickness ratio k of the passive layer and the active layer of the locking actuator of 3-4, 1.9-3, 1.3-1.9, 0.8-1.3 and 0.5-0.8 respectively.

[0020] The action execution priority is divided into three priorities: the first priority G1, the second priority G2 and the third priority G3. The maze-type interlocking state is a general locking state. The general locking means that the locking state is relatively stable and still allows slight looseness. At this time, the two maze-type interlocking intelligent structures constitute a double maze-type interlocking intelligent structure. Each maze-type interlocking intelligent structure is spirally bent into four sections, and the two maze-type interlocking intelligent structures are nested in each other.

[0021] The action execution priority is divided into five priorities: first priority G1, second priority G2, third priority G3, fourth priority G4 and fifth priority G5. When the maze-type interlocking state is a firmly locked state, firmly locked means that the locking state is very stable and no loosening is allowed. At this time, the two maze-type interlocking intelligent structures constitute a triple maze-type interlocking intelligent structure, each maze-type interlocking intelligent structure is spirally bent into six sections, and the two maze-type interlocking intelligent structures are nested in each other.

[0022] Double refers to two interlocking smart structures that form two interlocking circles when connected. Triple refers to two interlocking smart structures that form three interlocking circles when connected. Maze refers to a smart structure that resembles a maze when connected. The chirality of the smart structure is determined by the direction of the locking actuator. When the locking actuator is actuated in a clockwise direction, the chirality of the smart structure is also forward.

[0023] The present invention determines the maze type of the intelligent structure and the number of locking actuators to be prepared based on the locking requirements of the parts to be connected, and assigns the action execution priority of the locking actuators; selects shape memory polymer as the raw material, and adopts fused deposition 4D printing technology to prepare the intelligent structure; the intelligent structure prepared by 4D printing is arranged in an inverse and staggered manner with the parts to be connected, and under the synchronous stimulation of the external field, actions of different priorities are executed, ultimately forming a maze-like interlocking structure.

[0024] The beneficial effects of the present invention are:

[0025] 1. The present invention has the advantages of simple structure, self-drive, light weight, no pollution, reliable interlocking, etc., and has lower development cost than traditional locking connection devices.

[0026] 2. The present invention uses shape memory polymer as raw material, comprehensively considers the structural type of the intelligent structure, intelligent structure design parameters, 3D printing process parameters and the excitation temperature of temperature excitation, etc., to achieve rapid manufacturing of complex intelligent deformation structures, simplifying the design, manufacturing and assembly process of intelligent structure products.

[0027] 3. The present invention uses 4D printing technology to process smart materials. The prepared smart structure deforms under synchronous external field excitation, and finally forms a maze-like interlocking structure under a special spatial arrangement. It responds instantly to thermal excitation and can achieve reliable locking of the connected parts without applying external force. At the same time, the molding process is not limited by structural complexity. Compared with traditional manufacturing methods, it is easier to meet functional requirements.

[0028] 4. The structural type adopted by the present invention is a maze type. When multiple maze-like intelligent structures are interlocked with each other, they have a reliable locking connection effect, and the self-driving behavior of the intelligent structure can be controlled by changing the design parameters, making the interlocking process smooth and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the material arrangement of the active layer and passive layer of the locking actuator of the present invention;

[0030] Figure 2 Schematic diagram of the intelligent structure configuration and design parameters of the present invention;

[0031] Figure 3 This is a schematic diagram of the action execution process of a single intelligent structure of the present invention, wherein: Figure 3 (a) is a schematic diagram of the structure of the intelligent structure of the present invention before the action is performed; Figure 3 (b) is a schematic diagram of the structure of the intelligent structure during the execution of the action of the present invention; Figure 3 (c) is a schematic diagram of the structure of the intelligent structure of the present invention when the action is completed;

[0032] Figure 4 This is a schematic diagram of the intelligent structure prepared by the present invention achieving double maze-like interlocking and locking under temperature excitation and without external force application, wherein: Figure 4 (a) is a schematic diagram of the layout state of the intelligent structure of the present invention before the action is performed; Figure 4 (b) is a schematic diagram of the locking state after the intelligent structure action of the present invention is completed;

[0033] Figure 5This is a schematic diagram of the intelligent structure prepared by the present invention achieving triple maze-like interlocking and locking under temperature excitation and without external force application, wherein: Figure 5 (a) is a schematic diagram of the layout state of the intelligent structure of the present invention before the action is performed; Figure 5 (b) is a schematic diagram of the locking state after the intelligent structure action of the present invention is completed. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 2 As shown, the 4D-printed maze-like interlocking intelligent structure of the present invention includes a long non-executing segment, a plurality of locking actuators, and a plurality of short non-executing segments. One end of the long non-executing segment is fixed to a connector. Each locking actuator and short non-executing segment is staggered in sequence and connected end to end to form a locking segment. The two ends of the locking segment are respectively a locking actuator and a short non-executing segment. The locking segment is connected to the other end of the long non-executing segment through a locking actuator at one end. The locking actuator performs bending deformation, and the non-executing segment connects each locking actuator, and the end to end connection forms an undeformed intelligent structure. The long non-executing segment, the short non-executing segment, and each locking actuator are all made of shape memory polymer material.

[0036] like Figure 1 As shown, the locking actuator comprises a stacked active layer and a passive layer, with the active layer of each locking actuator located on the same side of the labyrinthine interlocking intelligent structure. The active layer is composed of a plurality of stacked printed layers, each of which includes several parallel print paths parallel to the length of the locking segment. The passive layer is composed of a plurality of stacked mesh printed layers, each of which includes several intersecting print paths and forms angles of 45° and -45° with the length of the locking segment. Both the long and short non-executing segments are composed of a plurality of stacked mesh printed layers, each of which includes several intersecting print paths and forms angles of 45° and -45° with the length of the locking segment.

[0037] The ratio k of the thickness of the passive layer to the active layer of each locking actuator is different; the side dimensions connecting the active layer and the passive layer of the locking actuator are the same, and the side dimensions connecting the locking actuator and the long non-executing section and the short non-executing section are the same.

[0038] The locking method of the labyrinth interlocking intelligent structure of the present invention comprises the following steps:

[0039] Step 1: Place two labyrinth-type interlocking intelligent structures between two oppositely spaced parts to be connected in opposite directions according to the same chirality. The fixed end of one end of each labyrinth-type interlocking intelligent structure is connected to one of its own parts to be connected, and the other end of each labyrinth-type interlocking intelligent structure is a free end and does not contact the other part to be connected; the opposite side of the locking actuator of the two labyrinth-type interlocking intelligent structures is the side where the active layer is located; in the initial state, the two labyrinth-type interlocking intelligent structures are in a straight line state and are arranged in parallel and spaced apart.

[0040] Step 2: Through external field stimulation, each locking actuator of each labyrinth interlocking intelligent structure is simultaneously bent and deformed toward the other labyrinth interlocking intelligent structure, driving the two labyrinth interlocking intelligent structures to deform from their respective free ends to the fixed ends with the same deformation scale, thereby forming a labyrinth-like interlocking state, such as Figure 3 (a) Figure 3 (b) and Figure 3 As shown in (c).

[0041] In step 2, the external field stimulation is specifically temperature stimulation, and the temperature stimulation is specifically 80-90° C., which is 20-30° C. higher than the glass transition temperature of the shape memory polymer.

[0042] In step 2, during the deformation process of the labyrinth interlocking intelligent structure, each locking actuator bends and deforms according to its own preset action execution priority, and every two adjacent non-executing segments are perpendicular to each other in the labyrinth interlocking state.

[0043] The action execution priorities of the locking actuators from the free end to the fixed end of the maze-type interlocking intelligent structure are arranged in order from high to low. The higher the action execution priority, the smaller the thickness ratio k between the passive layer and the active layer of the locking actuator and the shorter the action execution completion time during bending. The number of action execution priorities is the same as the number of locking actuators in each maze-type interlocking intelligent structure.

[0044] The action execution priority is specifically divided into three or five priorities: the first priority G1, the second priority G2, the third priority G3, the fourth priority G4 and the fifth priority G5 correspond to the thickness ratio k of the passive layer and the active layer of the locking actuator being 3-4, 1.9-3, 1.3-1.9, 0.8-1.3 and 0.5-0.8 respectively.

[0045] The action execution priority is determined according to the action execution completion time: G1 represents 20s-25s; G2 represents 15s-20s; G3 represents 10s-15s; G4 represents 5s-10s; G5 represents 0s-5s.

[0046] The action execution priority is divided into three priorities: the first priority G1, the second priority G2 and the third priority G3. When the maze-type interlocking state is a general locking state, the general locking means that the locking state is relatively stable and slight looseness is still allowed. At this time, the two maze-type interlocking intelligent structures constitute a double maze-type interlocking intelligent structure. Each maze-type interlocking intelligent structure is spirally bent into four sections, and the two maze-type interlocking intelligent structures are nested in each other.

[0047] The action execution priority is divided into five priorities: first priority G1, second priority G2, third priority G3, fourth priority G4 and fifth priority G5. When the maze-type interlocking state is a firmly locked state, firmly locked means that the locking state is very stable and no loosening is allowed. At this time, the two maze-type interlocking intelligent structures constitute a triple maze-type interlocking intelligent structure. Each maze-type interlocking intelligent structure is spirally bent into six sections, and the two maze-type interlocking intelligent structures are nested in each other.

[0048] Double refers to two interlocking smart structures that form two interlocking circles when connected. Triple refers to two interlocking smart structures that form three interlocking circles when connected. Maze refers to a smart structure that resembles a maze when connected. The chirality of the smart structure is determined by the direction of the locking actuator. When the locking actuator is actuated in a clockwise direction, the chirality of the smart structure is also forward.

[0049] Step 3: Remove the external field stimulation, and the strength of each locking actuator is restored to the strength of the initial state, so that the two parts to be connected are finally locked.

[0050] When preparing a maze-like interlocking intelligent structure, the present invention determines the required maze type and number of locking actuators for the intelligent structure based on the locking requirements of the connected parts, and assigns the action execution priority of the locking actuators. Based on the design rules of the locking actuators, the intelligent structure design parameter values ​​that meet the action execution priority are determined. A shape memory polymer is selected as the raw material, and 3D printing process parameters are selected to prepare the undeformed intelligent structure using fused deposition modeling technology. The intelligent structure design parameter values ​​include the width b and thickness h of the intelligent structure, the thickness ratio k of the passive and active layers of the locking actuators, the length a1 of the locking actuators, and the length a2 of the non-executing segments. The 3D printing process parameters include: print line width wp, print layer height hp, print nozzle temperature tp, and print speed vp.

[0051] like Figure 2As shown, the width b of the labyrinth-like interlocking intelligent structure is 5mm-10mm, the thickness h is 1mm, the length a1 of the locking actuator is 8mm-12mm, and the lengths a2 of the long and short non-actuating segments are 10mm-15mm. The 3D printing process parameters include: print line width wp, print layer height hp, print nozzle temperature tp, and print speed vp. In the specific implementation, the printing line width wp of the passive layer of the locking actuator is 0.4mm, the printing layer height hp is 0.1mm, the printing nozzle temperature tp is 190-210℃, and the printing speed vp is 50-60mm / s; the printing line width wp of the active layer of the locking actuator is 0.4mm, the printing layer height hp is 0.05mm, the printing nozzle temperature tp is 190-195℃, and the printing speed vp is 50-60mm / s; the printing line width wp of the non-executing segment of the locking actuator is 0.4mm, the printing layer height hp is 0.1mm, the printing nozzle temperature tp is 190-210℃, and the printing speed vp is 50-60mm / s.

[0052] Fused deposition modeling (FDM) prints the passive and active layers from the bottom up, with each layer within the passive and active layers printed repeatedly from the bottom up. Fused deposition modeling (FDM) prints the non-executing segments from the bottom up, with each layer within the non-executing segments printed repeatedly from the bottom up. The passive and active layers of the locking actuator, as well as each layer within the non-executing segments, are printed in a single pass with the nozzle at the same print height. The order in which each layer is printed is determined by the print sequence automatically generated by the 3D printing slicing software until all layers are printed.

[0053] Specific embodiments of the present invention are as follows:

[0054] Example 1:

[0055] 1) As the locking requirement of the connected parts is general locking, the intelligent structure type to be prepared is determined to be a double maze type, and the number of locking actuators is 3; the action execution priority of each locking actuator is assigned, from the fixed end to the free end, respectively G1, G3, and G5.

[0056] 2) Based on the design rules for the locking actuator, determine the design parameters of the smart structure that meet the action execution priority. The smart structure has a width of b = 8 mm and a thickness of h = 1 mm. The locking actuator has a length of a1 = 10 mm. The lengths of the three non-executing segments from the free end to the fixed end are a2 = 12 mm, 12 mm, and 13 mm, respectively. The thickness ratio k between the passive and active layers is: k = 3 for a locking actuator with priority G1, k = 1.5 for a locking actuator with priority G3, and k = 0.6 for a locking actuator with priority G5.

[0057] 3) Shape memory polymer was used as the raw material for the smart structure fabricated using fused deposition modeling (FDM) 3D printing, with printing performed in a repeated layer-by-layer fashion from bottom to top. The passive layer's material layout was at angles of 45° and -45° relative to the long sides of the smart structure, while the active layer's material layout was parallel to the long sides of the smart structure. The material layout of the non-actuating segment of the smart structure, perpendicular to the printing plane, was consistent with that of the passive layer. The passive layer of the locking actuator had a print line width of wp = 0.4 mm, a print layer height of hp = 0.1 mm, a print nozzle temperature of tp = 210°C, and a print speed of vp = 60 mm / s. The active layer had a print line width of wp = 0.4 mm, a print layer height of hp = 0.05 mm, a print nozzle temperature of tp = 195°C, and a print speed of vp = 50 mm / s. The non-actuating segment of the locking actuator had a print line width of wp = 0.4 mm, a print layer height of hp = 0.1 mm, a print nozzle temperature of tp = 210°C, and a print speed of vp = 60 mm / s.

[0058] 4) The intelligent structure prepared by 3D printing is then subjected to temperature excitation as the external field excitation. The excitation temperature is 85°C. Under the external field excitation, the locking actuators complete the bending action in descending order according to the priority, thereby obtaining a single maze-like intelligent structure, such as Figure 4 As shown in (b).

[0059] like Figure 4 (a) and Figure 4 (b) shows the schematic diagram of the intelligent structure before and after achieving double-maze interlocking under temperature excitation and without external force. After the free ends contact and interlocking, the bending action begins according to the locking actuator action execution priority sequence. Under synchronous external field excitation, the intelligent structure begins bending according to the locking actuator action execution priority sequence, and then interlocking is completed, achieving full interlocking and locking the connected parts.

[0060] Example 2:

[0061] 1) Based on the locking requirement of the connected parts for firm locking, the intelligent structure type to be prepared is determined to be a triple maze type, and the number of locking actuators is 5; the action execution priority of each locking actuator is assigned, from the fixed end to the free end, respectively G1, G2, G3, G4, and G5.

[0062] 2) Based on the design rules for the locking actuator, determine the design parameters of the smart structure that meet the action execution priority. The smart structure has a width of b = 8 mm and a thickness of h = 1 mm. The locking actuator has a length of a1 = 10 mm. The lengths of the three non-executing segments from the free end to the fixed end are a2 = 12 mm, 12 mm, 13 mm, 14 mm, and 15 mm, respectively. The thickness ratio k of the passive layer to the active layer is: k = 3 for a locking actuator with priority G1, k = 2 for a locking actuator with priority G2, k = 1.5 for a locking actuator with priority G3, k = 1 for a locking actuator with priority G4, and k = 0.6 for a locking actuator with priority G5.

[0063] 3) Shape memory polymer was used as the raw material, and the smart structure was fabricated using fused deposition modeling (3D printing), with printing performed in a bottom-up, repeated layer-by-layer manner. The passive layer's material layout was perpendicular to the long side of the smart structure, while the active layer's material layout was parallel to the long side of the smart structure. The non-actuating segment of the smart structure, perpendicular to the printing plane, was also arranged perpendicular to the long side of the smart structure. The passive layer of the locking actuator had a print line width of wp = 0.4 mm, a print layer height of hp = 0.1 mm, a print nozzle temperature of tp = 210°C, and a print speed of vp = 60 mm / s. The active layer of the locking actuator had a print line width of wp = 0.4 mm, a print layer height of hp = 0.05 mm, a print nozzle temperature of tp = 195°C, and a print speed of vp = 50 mm / s. The non-actuating segment of the locking actuator had a print line width of wp = 0.4 mm, a print layer height of hp = 0.1 mm, a print nozzle temperature of tp = 210°C, and a print speed of vp = 60 mm / s.

[0064] 4) The intelligent structure prepared by 3D printing uses temperature excitation as the external field excitation, and the excitation temperature is 85°C. Under the external field excitation, the locking actuators complete the bending action in sequence from high to low priority, thereby obtaining a single maze-like intelligent structure.

[0065] like Figure 5 (a) and Figure 5 (b) shows the schematic diagram of the intelligent structure before and after achieving triple maze-like interlocking under temperature excitation and without external force. After the free ends contact and interlocking, the bending action begins according to the locking actuator action priority sequence. Under synchronous external field excitation, the intelligent structure begins bending according to the locking actuator action priority sequence, and then interlocking is completed, achieving complete interlocking and securely locking the connected parts.

[0066] 4D printing combines traditional 3D printing technology and materials science, enabling printed objects to autonomously deform with changing environmental conditions. This invention applies 3D printing technology to intelligent locking devices. By varying design parameters, different response rates can be achieved in response to external stimuli. This allows the intelligent locking device to achieve orderly, controlled deformation during the locking process, free from external forces. By leveraging the programmability of 3D printing technology and the shape memory properties of shape memory materials, the device achieves controlled, autonomous deformation and locking functions, bringing more efficient and intelligent locking solutions to various fields.

Claims

1. A maze-like interlocking intelligent structure based on 4D printing, characterized by: It includes a long non-executing segment, several locking actuators and several short non-executing segments. One end of the long non-executing segment is fixed on the connecting piece. The locking actuators and short non-executing segments are arranged alternately in sequence and connected end to end to form a locking segment. The two ends of the locking segment are the locking actuator and the short non-executing segment respectively. The locking segment is connected to the other end of the long non-executing segment through the locking actuator at one end.

2. The 4D printing-based maze-like interlocking intelligent structure according to claim 1, characterized in that: The locking actuator includes an active layer and a passive layer arranged in a stacked manner, and the active layer of each locking actuator is located on the same side of the maze-type interlocking intelligent structure; the active layer is composed of a plurality of stacked printed layers, each of which includes a plurality of parallel printing paths and is parallel to the length direction of the locking section; the passive layer is composed of a plurality of stacked mesh printed layers, each of which includes a plurality of crossed printing paths and forms an angle of 45° and -45° with the length direction of the locking section.

3. The 4D printing-based maze-like interlocking intelligent structure according to claim 2, characterized in that: The ratio k of the thickness of the passive layer and the active layer of each locking actuator is different; the side dimensions connecting the active layer and the passive layer of the locking actuator are the same, and the side dimensions connecting the locking actuator and the long non-executing section and the short non-executing section are the same.

4. The 4D printing-based maze-like interlocking intelligent structure according to claim 1, characterized in that: The long non-executable section and the short non-executable section are both composed of a plurality of mesh-shaped printed layers stacked together, each mesh-shaped printed layer including a plurality of intersecting printing paths and forming angles of 45° and -45° with the length direction of the locking section.

5. The 4D printing-based maze-like interlocking intelligent structure according to claim 1, characterized in that: The long non-executing section, the short non-executing section and each locking actuator are all made of shape memory polymer material.

6. A locking method for a 4D-printed maze-type interlocking intelligent structure according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: Step 1: Place two labyrinthine interlocking smart structures in opposite directions according to the same chirality between two spaced-apart parts to be connected. The fixed end of each labyrinthine interlocking smart structure is connected to one of the parts to be connected, and the other end of each labyrinthine interlocking smart structure is a free end that does not contact the other part to be connected. The opposite side of the locking actuators of the two labyrinthine interlocking smart structures is the side where the active layer is located. In the initial state, the two labyrinthine interlocking smart structures are in a straight line and arranged in parallel with each other. Step 2: Through external field stimulation, each locking actuator of each labyrinth-like interlocking intelligent structure is simultaneously bent and deformed toward the other labyrinth-like interlocking intelligent structure, driving the two labyrinth-like interlocking intelligent structures to deform in the same scale from their respective free ends to their fixed ends, thereby forming a labyrinth-like interlocking state; Step 3: Remove the external field stimulation, and the strength of each locking actuator is restored to the strength of the initial state, so that the two parts to be connected are finally locked.

7. The locking method of a 4D printing-based labyrinth interlocking intelligent structure according to claim 6, characterized in that: In the step 2, the external field stimulation is specifically temperature stimulation, and the temperature stimulation is specifically 80-90°C.

8. The locking method of a 4D printing-based labyrinth interlocking intelligent structure according to claim 6, characterized in that: In the second step, during the deformation process of the labyrinth interlocking intelligent structure, each locking actuator is bent and deformed according to its own preset action execution priority, and every two adjacent non-executing segments are perpendicular to each other in the labyrinth interlocking state; The action execution priorities of the locking actuators from the free end to the fixed end of the maze-type interlocking intelligent structure are arranged in order from high to low. The higher the action execution priority, the smaller the thickness ratio k between the passive layer and the active layer of the locking actuator and the shorter the action execution completion time during bending. The number of action execution priorities is the same as the number of locking actuators in each maze-type interlocking intelligent structure.

9. The locking method of a 4D printing-based labyrinth interlocking intelligent structure according to claim 8, characterized in that: The action execution priority is specifically divided into three or five priorities: the first priority G1, the second priority G2, the third priority G3, the fourth priority G4 and the fifth priority G5 correspond to the thickness ratio k of the passive layer and the active layer of the locking actuator of 3-4, 1.9-3, 1.3-1.9, 0.8-1.3 and 0.5-0.8 respectively.

10. The locking method of a 4D printing-based labyrinth interlocking intelligent structure according to claim 9, characterized in that: The action execution priority is divided into three priorities: first priority G1, second priority G2 and third priority G3. When the labyrinth interlocking state is a general locking state, the two labyrinth interlocking intelligent structures constitute a double labyrinth interlocking intelligent structure. Each labyrinth interlocking intelligent structure is spirally bent into four sections, and the two labyrinth interlocking intelligent structures are nested in each other. The action execution priority is divided into five priorities: first priority G1, second priority G2, third priority G3, fourth priority G4 and fifth priority G5. The maze-type interlocking state is a firmly locked state. At this time, the two maze-type interlocking intelligent structures constitute a triple maze-type interlocking intelligent structure. Each maze-type interlocking intelligent structure is spirally bent into six sections, and the two maze-type interlocking intelligent structures are nested in each other.

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