Mechanical loading device for special-shaped main force-bearing component of large additive aircraft fuselage

Abstract

The invention discloses a mechanical loading device for a special-shaped main force-bearing component of a large additive aircraft fuselage. The mechanical loading device comprises an upper clamping and fixing frame, a lower clamping and fixing frame, a first force transfer mechanism, a second force transfer mechanism, a first push-pull force reversing mechanism and a second push-pull force reversing mechanism, the upper clamping and fixing frame is connected with an upper chuck of the uniaxial fatigue testing machine; the lower clamping fixing frame is connected with a lower chuck of the uniaxial fatigue testing machine; the first force transmission mechanism is arranged at one end of the upper clamping fixing frame, the second force transmission mechanism is arranged at the other end of the upper clamping fixing frame, and the first force transmission mechanism and the second force transmission mechanism are distributed in a left-right mirror symmetry mode relative to the lower chuck. The first push-pull force reversing mechanism is arranged on the first force transmission mechanism, the second push-pull force reversing mechanism is arranged on the second force transmission mechanism, and the first push-pull force reversing mechanism and the second push-pull force reversing mechanism are distributed in a left-right mirror symmetry mode relative to the lower chuck. The two ends of the test piece are connected with the first push-pull force reversing mechanism and the second push-pull force reversing mechanism respectively, and the middle of the test piece is connected with the lower clamping fixing frame.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical testing equipment, and in particular relates to a mechanical loading device for a special-shaped main load-bearing component of a large-scale additive aircraft fuselage. Background Art

[0002] Traditional uniaxial fatigue testing machines can only apply uniaxial loads to specimens during mechanical testing, so they are only capable of simple uniaxial loading tests. However, in fields such as aerospace, many components are subject to non-uniaxial loads. For example, the special-shaped primary load-bearing components of large additive aircraft fuselages experience more complex bending load conditions, and traditional uniaxial fatigue testing machines are currently unable to meet these loading requirements.

[0003] Therefore, at present, mechanical tests on specimens such as large additive aircraft fuselage special-shaped main load-bearing components can only be carried out through special-purpose bending fatigue loading testing machines. However, special-purpose bending fatigue loading testing machines are generally expensive and have complex structures, resulting in high costs for conducting bending fatigue loading tests on specimens such as large additive special-shaped main load-bearing components. Cost factors have also become a key constraint on the application and promotion of special-purpose bending fatigue loading testing machines. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a mechanical loading device for the special-shaped main load-bearing components of the fuselage of large additive aircraft, which can expand the uniaxial fatigue testing machine to the application scenario of bending fatigue loading of the special-shaped main load-bearing components of the fuselage of large additive aircraft. Compared with the existing special-purpose bending fatigue loading testing machine, the device has the characteristics of low price and simple structure, and can complete the bending fatigue loading test of specimens such as the special-shaped main load-bearing components of the fuselage of large additive aircraft at a relatively low cost, effectively extending the scope of application of the uniaxial fatigue testing machine, and can meet more complex load change conditions, so that the test data is closer to the actual usage conditions.

[0005] In order to achieve the above-mentioned objectives, the present invention adopts the following technical solutions: a mechanical loading device for a special-shaped main load-bearing component of a large additive aircraft fuselage, comprising an upper clamping and fixing frame, a lower clamping and fixing frame, a first force transmission mechanism, a second force transmission mechanism, a first push-pull force reversing mechanism and a second push-pull force reversing mechanism; the upper clamping and fixing frame is fixedly connected to the upper clamp of a uniaxial fatigue testing machine; the lower clamping and fixing frame is fixedly connected to the lower clamp of the uniaxial fatigue testing machine; the first force transmission mechanism is arranged at one end of the upper clamping and fixing frame, and the second force transmission mechanism is arranged at the other end of the upper clamping and fixing frame, and the first force transmission mechanism and the second force transmission mechanism are distributed in a left-right mirror-symmetric manner relative to the lower clamp; the first push-pull force reversing mechanism is arranged on the first force transmission mechanism, and the second push-pull force reversing mechanism is arranged on the second force transmission mechanism, and the first push-pull force reversing mechanism and the second push-pull force reversing mechanism are distributed in a left-right mirror-symmetric manner relative to the lower clamp; the two ends of the specimen are respectively connected to the first push-pull force reversing mechanism and the second push-pull force reversing mechanism, and the middle part of the specimen is connected to the lower clamping and fixing frame.

[0006] The upper clamping fixing frame includes an upper support plate, a support vertical plate, an upper clamping column pin and a reinforcing rib plate; the upper support plate is arranged horizontally; the upper clamping column pin is vertically fixed to the middle part of the upper surface of the upper support plate, and the upper clamping column pin is clamped and fixed with the upper clamping head of the uniaxial fatigue testing machine; the reinforcing rib plate is fixedly arranged on the upper surface of the upper support plate on both sides of the upper clamping column pin; the support vertical plate is arranged vertically, and the upper end of the support vertical plate is fixedly connected to the lower surface of the upper support plate. There are four support vertical plates, and the four support vertical plates are evenly distributed at the four corner points of the upper support plate.

[0007] A friction column is vertically arranged on the lower surface of the upper support plate, and the friction column is used to simulate the friction force generated by the test piece under actual working conditions.

[0008] The lower clamping fixing frame includes a lower support plate, an adapter seat, a lower clamping pin, an ear plate seat and an adapter hinge; the lower support plate is horizontally arranged; the adapter seat is vertically fixed to the middle of the lower surface of the lower support plate; the lower clamping pin is vertically fixed to the middle of the lower surface of the adapter seat, and the lower clamping pin is clamped and fixed with the lower clamp of the uniaxial fatigue testing machine; the ear plate seat is fixedly installed on the upper surface of the lower support plate, and there are four ear plate seats, and two ear plate seats are arranged side by side at both ends of the lower support plate; the adapter hinge is horizontally fixed in the four ear plate seats, and the adapter ear plate on the lower surface of the middle part of the specimen is hinged to the adapter hinge.

[0009] The first force transmission mechanism and the second force transmission mechanism have the same structure, and both include a force transmission rod, a crank wheel, a crank wheel axle, a bearing seat and an omnidirectional movable connection assembly; one end of the force transmission rod is plugged and positioned with the adapter seat through a U-shaped groove, and a rod seat fastening screw is fixedly installed between the force transmission rod and the adapter seat; the bearing seat is fixedly installed at the bottom of the supporting vertical plate; the crank wheel axle is fixedly installed at the rotation center of the crank wheel, and both ends of the crank wheel axle are rotatably connected to the bearing seat; the other end of the force transmission rod is connected to the front surface of the crank wheel through the omnidirectional movable connection assembly.

[0010] The omnidirectional movable connection assembly includes a first slide rail, a first slider, a second slide rail and a second slider; the first slide rail is fixedly installed on the force transmission rod, and the first slide rail is distributed parallel to the force transmission rod; the first slider is slidably connected to the first slide rail; the second slide rail is fixedly installed on the front surface of the crank wheel, and the second slide rail and the first slide rail are cross-distributed; the second slider is slidably connected to the second slide rail, and the center of the second slider is connected to the center of the first slide rail through the slider hinge shaft, and the slider hinge shaft is distributed parallel to the crank wheel shaft; the second slide rail and the rotation center of the crank wheel are eccentrically distributed.

[0011] The first push-pull force reversing mechanism and the second push-pull force reversing mechanism have the same structure, both including a first force rod, a first adapter angle bracket, a first locking positioning block, a first locking positioning pin, a second force rod, a second adapter angle bracket, a second locking positioning block, a second locking positioning pin, a force reversing adjustment block, a force reversing guide plate, an extension support bracket, a specimen connection angle bracket and a follow-up connection assembly; the first force rod and the second force rod are vertically distributed side by side, and the second force rod is located between the lower clamp of the uniaxial fatigue testing machine and the first force rod; the bottom ends of the first force rod and the second force rod are connected to the rear surface of the crank wheel through the follow-up connection assembly; the first adapter angle bracket is fixedly installed on the top end of the first force rod, the first locking positioning block is fixedly installed on the top of the first adapter angle bracket, the first locking positioning pin is horizontally installed on the first locking positioning block, and a first return spring is provided between the first locking positioning pin and the first locking positioning block; the second adapter angle bracket is fixedly installed on the top end of the second force rod, and the second locking positioning block is fixedly installed The second locking positioning pin is installed horizontally on the top of the second transfer angle bracket, and a second return spring is provided between the second locking positioning pin and the second locking positioning block; the combination of the first force applying rod, the first transfer angle bracket, the first locking positioning block, and the first locking positioning pin and the combination of the second force applying rod, the second transfer angle bracket, the second locking positioning block, and the second locking positioning pin are mirror-symmetrically distributed relative to the rotation center of the crank wheel; the force reversing adjustment block and the first locking positioning pin are mirror-symmetrically distributed. The pin or the second locking positioning pin is fixedly connected and matched, and a force reversing guide slide pin is fixedly installed on the force reversing adjustment block; the specimen connection angle bracket is fixedly connected and matched with the specimen, and the top of the extension support bracket is fixedly connected to the specimen connection angle bracket, and the force reversing guide plate is horizontally fixed on the bottom end of the extension support bracket, and a force reversing guide slot is provided on the force reversing guide plate, and the force reversing guide slide pin is located in the force reversing guide slot; the force reversing adjustment block has sliding freedom relative to the force reversing guide plate.

[0012] The follower connecting assembly includes a third slide rail and a third slider; the third slide rail is fixedly mounted on the rear surface of the crank wheel, and the third slide rail and the second slide rail are cross-distributed; the third slider is slidably connected to the third slide rail, and the third slide rail and the rotation center of the crank wheel are eccentrically distributed, and the third slide rail is located above the crank wheel axle; the bottom end of the first force rod or the second force rod is connected to the center of the third slider through the force rod hinge shaft, and the force rod hinge shaft is distributed parallel to the crank wheel axle.

[0013] Beneficial effects of the present invention:

[0014] The mechanical loading device for the special-shaped main load-bearing components of the large-scale additive aircraft fuselage of the present invention can expand the uniaxial fatigue testing machine to the application scenario of bending fatigue loading of the special-shaped main load-bearing components of the large-scale additive aircraft fuselage. Compared with the existing special-purpose bending fatigue loading testing machine, it has the characteristics of low price and simple structure. It can complete the bending fatigue loading test of specimens such as the special-shaped main load-bearing components of the large-scale additive aircraft fuselage at a relatively low cost, effectively extending the scope of application of the uniaxial fatigue testing machine, and can meet more complex load change conditions, so that the test data is closer to the actual usage conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of a mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component (when used in conjunction with a uniaxial fatigue testing machine) according to the present invention;

[0016] Figure 2 This is a schematic structural diagram of a mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component according to the present invention;

[0017] Figure 3 It is a structural schematic diagram of the upper clamping and fixing frame of the present invention;

[0018] Figure 4 It is a structural schematic diagram of the lower clamping fixing frame of the present invention;

[0019] Figure 5 Schematic diagram of the structure of the first / second force transmission mechanism of the present invention;

[0020] Figure 6 for Figure 5 Enlarged view of middle part I;

[0021] Figure 7 Schematic diagram of the structure of the first / second push-pull force reversing mechanism of the present invention;

[0022] Figure 8 for Figure 2 Enlarged view of middle part II;

[0023] In the figure, A—upper clamping fixed frame, B—lower clamping fixed frame, C—first force transmission mechanism, D—second force transmission mechanism, E—first push-pull force reversing mechanism, F—second push-pull force reversing mechanism, G—uniaxial fatigue testing machine, 1—upper chuck, 2—lower chuck, 3—test piece, 4—upper support plate, 5—support vertical plate, 6—upper clamping column pin, 7—reinforcement rib plate, 8—friction column, 9—lower support plate, 10—adapter seat, 11—lower clamping column pin, 12—ear plate seat, 13—adapter hinge shaft, 14—adapter ear plate, 15—force transmission rod, 16—crank wheel, 17—crank wheel shaft, 18—bearing seat, 19—rod seat fastening Screw, 20—first slide rail, 21—first slider, 22—second slide rail, 23—second slider, 24—first force rod, 25—first adapter angle bracket, 26—first locking positioning block, 27—first locking positioning pin, 28—second force rod, 29—second adapter angle bracket, 30—second locking positioning block, 31—second locking positioning pin, 32—force reversing adjustment block, 33—force reversing guide plate, 34—extension support frame, 35—test piece connection angle bracket, 36—force reversing guide slide pin, 37—force reversing guide slide groove, 38—third slide rail, 39—third slider, 40—force rod hinge shaft. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figures 1 to 8 As shown, a mechanical loading device for a special-shaped main load-bearing component of a large-scale additive aircraft fuselage comprises an upper clamping fixing frame A, a lower clamping fixing frame B, a first force transmission mechanism C, a second force transmission mechanism D, a first push-pull force reversing mechanism E, and a second push-pull force reversing mechanism F; the upper clamping fixing frame A is fixedly connected to the upper clamping head 1 of the uniaxial fatigue testing machine G; the lower clamping fixing frame B is fixedly connected to the lower clamping head 2 of the uniaxial fatigue testing machine G; the first force transmission mechanism C is arranged at one end of the upper clamping fixing frame A, and the second force transmission mechanism D is arranged at the upper clamping fixing frame At the other end of the clamping fixed frame A, the first force transmission mechanism C and the second force transmission mechanism D are distributed in a left-right mirror symmetry relative to the lower clamping head 2; the first push-pull force reversing mechanism E is arranged on the first force transmission mechanism C, and the second push-pull force reversing mechanism F is arranged on the second force transmission mechanism D, and the first push-pull force reversing mechanism E and the second push-pull force reversing mechanism F are distributed in a left-right mirror symmetry relative to the lower clamping head 2; the two ends of the specimen 3 are respectively connected to the first push-pull force reversing mechanism E and the second push-pull force reversing mechanism F, and the middle part of the specimen 3 is connected to the lower clamping fixed frame B.

[0026] The upper clamping fixing frame A includes an upper support plate 4, a support vertical plate 5, an upper clamping column pin 6 and a reinforcing rib plate 7; the upper support plate 4 is arranged horizontally; the upper clamping column pin 6 is vertically fixed in the middle of the upper surface of the upper support plate 4, and the upper clamping column pin 6 is clamped and fixed with the upper clamping head 1 of the uniaxial fatigue testing machine G; the reinforcing rib plate 7 is fixedly arranged on the upper surface of the upper support plate 4 on both sides of the upper clamping column pin 6; the support vertical plate 5 is arranged vertically, and the upper end of the support vertical plate 5 is fixedly connected to the lower surface of the upper support plate 4. There are four support vertical plates 5, and the four support vertical plates 5 are evenly distributed at the four corner points of the upper support plate 4.

[0027] A friction column 8 is vertically provided on the lower surface of the upper support plate 4 , and the friction column 8 is used to simulate the friction force generated by the test piece 3 under actual working conditions.

[0028] The lower clamping fixing frame B includes a lower support plate 9, an adapter seat 10, a lower clamping pin 11, an ear plate seat 12 and a transfer hinge 13; the lower support plate 9 is horizontally arranged; the transfer seat 10 is vertically fixed in the middle of the lower surface of the lower support plate 9; the lower clamping pin 11 is vertically fixed in the middle of the lower surface of the adapter seat 10, and the lower clamping pin 11 is clamped and fixed with the lower clamping head 2 of the uniaxial fatigue testing machine G; the ear plate seat 12 is fixedly installed on the upper surface of the lower support plate 9, and there are four ear plate seats 12, and two ear plate seats 12 are arranged side by side at both ends of the lower support plate 9; the transfer hinge 13 is horizontally fixed and passed through the four ear plate seats 12, and the transfer ear plate 14 on the lower surface of the middle part of the specimen 3 is hinged to the transfer hinge 13.

[0029] The first force transmission mechanism C and the second force transmission mechanism D have the same structure, both including a force transmission rod 15, a crank wheel 16, a crank wheel axle 17, a bearing seat 18 and an omnidirectional movable connection assembly; one end of the force transmission rod 15 is plugged and positioned with the adapter seat 10 through a U-shaped groove, and a rod seat fastening screw 19 is fixedly installed between the force transmission rod 15 and the adapter seat 10; the bearing seat 18 is fixedly installed at the bottom of the supporting vertical plate 5; the crank wheel axle 17 is fixedly installed at the rotation center of the crank wheel 16, and both ends of the crank wheel axle 17 are rotatably connected to the bearing seat 18; the other end of the force transmission rod 15 is connected to the front surface of the crank wheel 16 through an omnidirectional movable connection assembly.

[0030] The omnidirectional movable connection assembly includes a first slide rail 20, a first slider 21, a second slide rail 22 and a second slider 23; the first slide rail 20 is fixedly installed on the force transmission rod 15, and the first slide rail 20 is distributed parallel to the force transmission rod 15; the first slider 21 is slidably connected to the first slide rail 20; the second slide rail 22 is fixedly installed on the front surface of the crank wheel 16, and the second slide rail 22 and the first slide rail 20 are cross-distributed; the second slider 23 is slidably connected to the second slide rail 22, and the center of the second slider 23 is connected to the center of the first slide rail 20 through a slider hinge shaft, and the slider hinge shaft is distributed parallel to the crank wheel shaft 17; the second slide rail 22 is eccentrically distributed with the rotation center of the crank wheel 16.

[0031] The first push-pull force reversing mechanism E and the second push-pull force reversing mechanism F have the same structure, both including a first force rod 24, a first adapter angle bracket 25, a first locking positioning block 26, a first locking positioning pin 27, a second force rod 28, a second adapter angle bracket 29, a second locking positioning block 30, a second locking positioning pin 31, a force reversing adjustment block 32, a force reversing guide plate 33, an extension support frame 34, a specimen connection angle bracket 35 and a follower connection assembly; the first force rod 24 and the second force rod 28 are vertically distributed side by side, and the second force rod 28 is located between the lower chuck 2 of the uniaxial fatigue testing machine G and the first force rod. The first force rod 24 is connected to the second force rod 28; the bottom ends of the first force rod 24 and the second force rod 28 are connected to the rear surface of the crank wheel 16 through a follower connection assembly; the first adapter angle bracket 25 is fixedly mounted on the top of the first force rod 24, the first locking positioning block 26 is fixedly mounted on the top of the first adapter angle bracket 25, the first locking positioning pin 27 is horizontally mounted on the first locking positioning block 26, and a first return spring is provided between the first locking positioning pin 27 and the first locking positioning block 26; the second adapter angle bracket 29 is fixedly mounted on the top of the second force rod 28, and the second locking positioning block 30 is fixedly mounted At the top of the second adapter angle bracket 29, the second locking positioning pin 31 is horizontally installed on the second locking positioning block 30, and a second return spring is provided between the second locking positioning pin 31 and the second locking positioning block 30; the combination of the first force rod 24, the first adapter angle bracket 25, the first locking positioning block 26, and the first locking positioning pin 27 and the combination of the second force rod 28, the second adapter angle bracket 29, the second locking positioning block 30, and the second locking positioning pin 31 are mirror-symmetrically distributed relative to the rotation center of the crank wheel 16; the force reversing adjustment block 32 and the first locking positioning The pin 27 or the second locking positioning pin 31 is fixedly connected and matched, and a force reversing guide slide pin 36 is fixedly installed on the force reversing adjustment block 32; the specimen connection angle bracket 35 is fixedly connected and matched with the specimen 3, and the top of the extension support bracket 34 is fixedly connected to the specimen connection angle bracket 35, and the force reversing guide plate 33 is horizontally fixed on the bottom end of the extension support bracket 34, and a force reversing guide slot 37 is provided on the force reversing guide plate 33, and the force reversing guide slide pin 36 is located in the force reversing guide slot 37; the force reversing adjustment block 32 has sliding freedom relative to the force reversing guide plate 33.

[0032] The follower connecting assembly includes a third slide rail 38 and a third slider 39; the third slide rail 38 is fixedly mounted on the rear surface of the crank wheel 16, and the third slide rail 38 and the second slide rail 22 are cross-distributed; the third slider 39 is slidably connected to the third slide rail 38, and the third slide rail 38 is eccentrically distributed with respect to the rotation center of the crank wheel 16, and the third slide rail 38 is located above the crank wheel axle 17; the bottom end of the first force rod 24 or the second force rod 28 is connected to the center of the third slider 39 through the force rod hinge shaft 40, and the force rod hinge shaft 40 is distributed parallel to the crank wheel axle 17.

[0033] The following describes a one-time use process of the present invention in conjunction with the accompanying drawings:

[0034] After the specimen 3 is assembled with the uniaxial fatigue testing machine G through the mechanical loading device of the present invention, the force reversing adjustment blocks 32 in the first push-pull force reversing mechanism E and the second push-pull force reversing mechanism F are fixedly connected to the top of the first force rod 24, and the second force rod 28 is in an unused state.

[0035] During the loading test, the lower chuck 2 of the uniaxial fatigue testing machine G outputs a uniaxial load, which will act on the middle of the specimen 3 in sequence through the lower clamping pin 11, the adapter seat 10, the lower support plate 9, the ear plate seat 12 and the adapter hinge shaft 13. At the same time, the uniaxial load will also act on the two crank wheels 16 in sequence through the lower clamping pin 11, the adapter seat 10, the force transmission rod 15 and the omnidirectional movable connection assembly, thereby driving the crank wheel 16 to swing around its rotation center. At this time, the swinging action of the crank wheel 16 will be converted into a thrust load of the first force rod 24 through the follow-up connection assembly. The thrust load will act on the two ends of the specimen 3 in sequence through the force reversing adjustment block 32, the force reversing guide plate 33, the extended support frame 34 and the specimen connection angle frame 35, and finally the uniaxial load output by the lower chuck 2 will be converted into a thrust load at both ends of the specimen 3, thereby realizing a bending fatigue loading test with thrust at both ends.

[0036] Similarly, when the force reversing adjustment blocks 32 in the first push-pull force reversing mechanism E and the second push-pull force reversing mechanism F are fixedly connected to the top end of the second force rod 28, the first force rod 24 is in an unused state, and the swinging action of the crank wheel 16 will be converted into a tensile load of the second force rod 28 through the follow-up connection assembly. The tensile load is also applied to the two ends of the specimen 3 in turn through the force reversing adjustment block 32, the force reversing guide plate 33, the extended support frame 34 and the specimen connection angle frame 35, and finally the uniaxial load output by the lower chuck 2 is converted into a tensile load at both ends of the specimen 3, thereby realizing a bending fatigue loading test of tension at both ends.

[0037] In addition, when the force reversing adjustment block 32 in the first push-pull force reversing mechanism E is fixedly connected to the top of the first force rod 24, and the force reversing adjustment block 32 in the second push-pull force reversing mechanism F is fixedly connected to the top of the second force rod 28, or when the force reversing adjustment block 32 in the first push-pull force reversing mechanism E is fixedly connected to the top of the second force rod 28, and the force reversing adjustment block 32 in the second push-pull force reversing mechanism F is fixedly connected to the first force rod 24, the swing rotation of the crank wheel 16 on one side The action of the lower chuck 2 will be converted into a thrust load of the first force rod 24 through the follow-up connection assembly, and the thrust load will act on one end of the specimen 3; at the same time, the swinging action of the crank wheel 16 on the other side will be converted into a tensile load of the second force rod 28 through the follow-up connection assembly, and the tensile load will act on the other end of the specimen 3, and finally the uniaxial load output by the lower chuck 2 will be converted to the two ends of the specimen 3, and a complex stress state with a thrust load at one end and a tensile load at the other end will be formed, thereby realizing a bending fatigue loading test with a complex stress state.

[0038] The solutions in the embodiments are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications that do not depart from the scope of protection of the present invention are included in the scope of protection of the present invention.

Claims

1. A mechanical loading device for special-shaped main load-bearing components of a large additive aircraft fuselage, characterized by: It includes an upper clamping and fixing frame, a lower clamping and fixing frame, a first force transmission mechanism, a second force transmission mechanism, a first push-pull force reversing mechanism and a second push-pull force reversing mechanism; the upper clamping and fixing frame is fixedly connected to the upper clamping head of the uniaxial fatigue testing machine; the lower clamping and fixing frame is fixedly connected to the lower clamping head of the uniaxial fatigue testing machine; the first force transmission mechanism is arranged at one end of the upper clamping and fixing frame, and the second force transmission mechanism is arranged at the other end of the upper clamping and fixing frame, and the first force transmission mechanism and the second force transmission mechanism are mirror-symmetrically distributed relative to the lower clamp; the first push-pull force reversing mechanism is arranged on the first force transmission mechanism, and the second push-pull force reversing mechanism is mirror-symmetrically distributed relative to the lower clamp; the two ends of the specimen are respectively connected to the first push-pull force reversing mechanism and the second push-pull force reversing mechanism, and the middle part of the specimen is connected to the lower clamping and fixing frame.

2. The mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component according to claim 1, characterized in that: The upper clamping fixing frame includes an upper support plate, a support vertical plate, an upper clamping column pin and a reinforcing rib plate; the upper support plate is arranged horizontally; the upper clamping column pin is vertically fixed to the middle part of the upper surface of the upper support plate, and the upper clamping column pin is clamped and fixed with the upper clamping head of the uniaxial fatigue testing machine; the reinforcing rib plate is fixedly arranged on the upper surface of the upper support plate on both sides of the upper clamping column pin; the support vertical plate is arranged vertically, and the upper end of the support vertical plate is fixedly connected to the lower surface of the upper support plate. There are four support vertical plates, and the four support vertical plates are evenly distributed at the four corner points of the upper support plate.

3. The mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component according to claim 2, characterized in that: A friction column is vertically arranged on the lower surface of the upper support plate, and the friction column is used to simulate the friction force generated by the test piece under actual working conditions.

4. The mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component according to claim 2, characterized in that: The lower clamping fixing frame includes a lower support plate, an adapter seat, a lower clamping pin, an ear plate seat and an adapter hinge; the lower support plate is horizontally arranged; the adapter seat is vertically fixed to the middle of the lower surface of the lower support plate; the lower clamping pin is vertically fixed to the middle of the lower surface of the adapter seat, and the lower clamping pin is clamped and fixed with the lower clamp of the uniaxial fatigue testing machine; the ear plate seat is fixedly installed on the upper surface of the lower support plate, and there are four ear plate seats, and two ear plate seats are arranged side by side at both ends of the lower support plate; the adapter hinge is horizontally fixed in the four ear plate seats, and the adapter ear plate on the lower surface of the middle part of the specimen is hinged to the adapter hinge.

5. The mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component according to claim 4, characterized in that: The first force transmission mechanism and the second force transmission mechanism have the same structure, and both include a force transmission rod, a crank wheel, a crank wheel axle, a bearing seat and an omnidirectional movable connection assembly; one end of the force transmission rod is plugged and positioned with the adapter seat through a U-shaped groove, and a rod seat fastening screw is fixedly installed between the force transmission rod and the adapter seat; the bearing seat is fixedly installed at the bottom of the supporting vertical plate; the crank wheel axle is fixedly installed at the rotation center of the crank wheel, and both ends of the crank wheel axle are rotatably connected to the bearing seat; the other end of the force transmission rod is connected to the front surface of the crank wheel through the omnidirectional movable connection assembly.

6. The mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component according to claim 5, characterized in that: The omnidirectional movable connection assembly includes a first slide rail, a first slider, a second slide rail and a second slider; the first slide rail is fixedly installed on the force transmission rod, and the first slide rail is distributed parallel to the force transmission rod; the first slider is slidably connected to the first slide rail; the second slide rail is fixedly installed on the front surface of the crank wheel, and the second slide rail and the first slide rail are cross-distributed; the second slider is slidably connected to the second slide rail, and the center of the second slider is connected to the center of the first slide rail through the slider hinge shaft, and the slider hinge shaft is distributed parallel to the crank wheel shaft; the second slide rail and the rotation center of the crank wheel are eccentrically distributed.

7. The mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component according to claim 5, characterized in that: The first push-pull force reversing mechanism and the second push-pull force reversing mechanism have the same structure, both including a first force rod, a first adapter angle bracket, a first locking positioning block, a first locking positioning pin, a second force rod, a second adapter angle bracket, a second locking positioning block, a second locking positioning pin, a force reversing adjustment block, a force reversing guide plate, an extension support bracket, a specimen connection angle bracket and a follow-up connection assembly; the first force rod and the second force rod are vertically distributed side by side, and the second force rod is located between the lower clamp of the uniaxial fatigue testing machine and the first force rod; the bottom ends of the first force rod and the second force rod are connected to the rear surface of the crank wheel through the follow-up connection assembly; the first adapter angle bracket is fixedly installed on the top end of the first force rod, the first locking positioning block is fixedly installed on the top of the first adapter angle bracket, the first locking positioning pin is horizontally installed on the first locking positioning block, and a first return spring is provided between the first locking positioning pin and the first locking positioning block; the second adapter angle bracket is fixedly installed on the top end of the second force rod, and the second locking positioning block is fixedly installed The second locking positioning pin is installed horizontally on the top of the second transfer angle bracket, and a second return spring is provided between the second locking positioning pin and the second locking positioning block; the combination of the first force applying rod, the first transfer angle bracket, the first locking positioning block, and the first locking positioning pin and the combination of the second force applying rod, the second transfer angle bracket, the second locking positioning block, and the second locking positioning pin are mirror-symmetrically distributed relative to the rotation center of the crank wheel; the force reversing adjustment block and the first locking positioning pin are mirror-symmetrically distributed. The pin or the second locking positioning pin is fixedly connected and matched, and a force reversing guide slide pin is fixedly installed on the force reversing adjustment block; the specimen connection angle bracket is fixedly connected and matched with the specimen, and the top of the extension support bracket is fixedly connected to the specimen connection angle bracket, and the force reversing guide plate is horizontally fixed on the bottom end of the extension support bracket, and a force reversing guide slot is provided on the force reversing guide plate, and the force reversing guide slide pin is located in the force reversing guide slot; the force reversing adjustment block has sliding freedom relative to the force reversing guide plate.

8. The mechanical loading device for a large-scale additive aircraft fuselage special-shaped main load-bearing component according to claim 7, characterized in that: The follower connecting assembly includes a third slide rail and a third slider; the third slide rail is fixedly mounted on the rear surface of the crank wheel, and the third slide rail and the second slide rail are cross-distributed; the third slider is slidably connected to the third slide rail, and the third slide rail and the rotation center of the crank wheel are eccentrically distributed, and the third slide rail is located above the crank wheel axle; the bottom end of the first force rod or the second force rod is connected to the center of the third slider through the force rod hinge shaft, and the force rod hinge shaft is distributed parallel to the crank wheel axle.

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