A tensile-bending-torsional multi-axial fatigue load loading structure

Abstract

The application discloses a tensile-bending-torsional multi-axial fatigue load loading structure, which comprises an I-shaped connecting rod, recesses and through holes are arranged at both ends of the I-shaped connecting rod to allow installation of actuator connecting ears, the actuator connecting ears are fixed through connecting pins, a through hole is arranged in the middle of the I-shaped connecting rod, a positioning ear is arranged on one side of the I-shaped connecting rod to connect a tensile actuator, and a torsional ring limiting structure is arranged on the other side of the I-shaped connecting rod, the center of the torsional ring limiting structure is a connecting clamp, one end of the connecting clamp is connected with the I-shaped connecting rod, one end of the connecting clamp is connected with a test piece through a fixing groove and a fixing pin, a cylindrical shaft is arranged in the middle of the connecting clamp to allow installation of a bearing, the outer ring of the bearing is matched with the recess of a bearing base, the center of the bearing base is a through hole to allow the connecting clamp to pass through, and a bearing cover plate with a through hole is arranged to cover the ball bearing in the bearing base. The structural design of the application solves the motion interference problem of multi-axial loading, allows tensile-bending-torsional multi-axial fatigue load loading, and can meet different test requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of multi-axial structure fatigue test, and particularly relates to a tensile-bending-torsion multi-axial fatigue load loading structure. BACKGROUND

[0002] Multi-axial fatigue test refers to fatigue performance detection of materials, parts, engineering structures and the like under specified conditions. The most important difference between the multi-axial fatigue test and conventional fatigue is that the load condition of the structure is complex, and is often in the form of biaxial load such as biaxial tension, biaxial compression, “tensile-torsion” and the like, and triaxial load such as tensile-bending-torsion. For conventional multi-axial load test, the test can be performed on a standard multi-axial fatigue test machine. For more unconventional multi-axial fatigue test, a suitable fixture structure needs to be designed to transfer the load for fatigue test.

[0003] The existing multi-axial fatigue test is usually in the form of biaxial load, and is allowed to be performed on a “tensile-bending” or “tensile-torsion” test machine. For triaxial load in which tensile-bending-torsion load acts simultaneously, a suitable load transfer structure is designed to build a test platform for test. However, the following problems still exist.

[0004] 1) When bending and torsion load is generated by the action of double actuators, displacement in an undesired direction is generated, resulting in motion interference.

[0005] 2) The actuator cannot bear radial load. When multi-axial load acts, the elastic deformation of the fixture structure under the influence of the load causes the actuator to be deformed by radial force.

[0006] 3) The switching of tensile, bending and torsion load in three loading modes of single action, two-way combination and three-way simultaneous action is not smooth, and the operation is troublesome.

[0007] 4) Tensile, bending and torsion load easily affects the fixture structure. SUMMARY

[0008] In order to solve the problems of the prior art, the present application provides a tensile-bending-torsion multi-axial fatigue load loading structure, which solves the problem of motion interference in multi-axial loading by structural design, allows tensile-bending-torsion multi-axial fatigue load loading, and can meet different test requirements.

[0009] In order to achieve the above purpose, the present application provides the following scheme: a tensile-bending-torsion multi-axial fatigue load loading structure, comprising:

[0010] The connecting rod transmission structure can be connected with the torsion ring limiting structure and the actuator, providing a transmission path for the actuator load, allowing the loading of three kinds of loads of stretching, bending and torsion. The main configuration of the connecting rod transmission structure is an I-beam, both ends of which are provided with positioning holes for connecting pins, allowing the installation of connecting pins and actuator connecting ears, the tail of the actuator connecting ear is provided with a thread, which is matched with the threaded groove on the actuator; the middle of the I-beam is provided with four symmetrically arranged installation round holes, one side is provided with a positioning ear, the positioning ear is provided with a threaded hole, and a bolt is used for fixing, the installation ear is provided with a pin hole allowing the connection of the actuator, and the other side is provided with a connecting clamp, which is fixed by a bolt to connect the torsion ring limiting structure.

[0011] The torsion ring limiting structure is designed in the form of bearing force transmission, and a connecting clamp is arranged at the center. The connecting clamp is divided into three sections, i.e. a clamping section, a shaft section and a connecting section. The shaft section of the connecting clamp is cylindrical and can be matched with an outer ring bearing. The front side is a clamping section of the clamp, and the rear side is a connecting section of the clamp. The bearing is a ball bearing, and the front end is provided with a cover plate, and the rear end is provided with a bearing base for axial positioning of the bearing. The clamping section of the connecting clamp is provided in the form of double ear pieces, and the ear pieces are provided with round holes for fixing test pieces. The distance between the ear pieces is matched with the thickness of the test piece. The connecting section of the connecting clamp is a square column, and is connected with the connecting rod transmission structure. The side surface of the bearing base is provided with a threaded groove, allowing the installation of a universal ball joint.

[0012] The outer frame provides a placing seat for the torsion ring limiting structure and a vertical motion constraint frame. The placing seat is a square box type with open ends, which can support the torsion ring limiting structure at a certain height before the structure is built and the test starts. The motion constraint frame is placed on both sides of the torsion ring limiting structure, and is in the form of a straight triangular steel with a rib plate at the center. The vertical side is in close contact with the universal ball joint to form a point-surface contact, and the ground side is fixed to the ground by anchor bolts.

[0013] Preferably, the bending and torsional load of the structure is generated by two bending and torsional actuators, which are connected with the I-beam through actuator connecting ears and connecting pins. Through the characteristics of ear pin structure hinging, the rotation of the ear around the pin eliminates the radial force generated by the movement of the clamp structure caused by the loading of the bending and torsional actuator on the actuator. A gap is left between the connecting ear and the I-beam to eliminate the influence of the force generated by the tensile actuator on the bending and torsional actuator.

[0014] Preferably, the bearing cooperates with the shaft section of the connecting clamp, and the rotational torque of the inner ring of the bearing can be transmitted to the test piece through the clamp without generating torque on the bearing base, cover plate, outer frame and universal ball joint installed on the bearing. When subjected to a bending moment, the torsion ring limiting structure makes the test piece only bend in the vertical direction under the contact restriction of the universal ball joint and the outer frame.

[0015] Preferably, the bending-torsion actuator is loaded with the same load, the same direction, the same frequency, and the bending moment can be applied to the test piece through the connecting rod transmission structure, and the torsion moment can be applied by differential loading. The bending moment, the torsion moment and the tension can be smoothly transmitted to the test piece through the torsion ring limiting structure without damaging the clamp. Therefore, the switching of different loading modes can be realized, and the operation is simple.

[0016] The beneficial effects of the present application are as follows:

[0017] 1. The load transmission structure is simple and reasonable in design, convenient to operate, the structural design solves the motion interference problem of multi-axial loading, makes the test loading more smooth, and the load size control more accurate; the design of the torsion ring limiting structure allows independent and combined loading of the bending moment and the torsion load, and the switching of the loading mode is smooth, which can meet different test requirements.

[0018] 2. Different forms of multi-axial test pieces only need to design different connection clamps in the center of the torsion ring limiting structure according to the connection requirements of the test piece, that is, different clamping sections are designed and replaced, and the convenient application of the load transmission structure is realized.

[0019] 3. In order to realize the stable application of the bending moment and the torsion load, double actuators are used for control, and a connecting rod transmission structure based on an I-beam is designed to transmit the load. The connection of each part of the load transmission structure is simple and reliable, and the design of each part is convenient for installation and disassembly. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 A three-dimensional schematic diagram of the overall structure of a tensile-bending-torsional multi-axial fatigue load loading structure is provided for the present application.

[0022] Figure 2 A three-dimensional schematic diagram of the assembly relationship of each component of the connecting rod transmission structure of a tensile-bending-torsional multi-axial fatigue load loading structure is provided for the present application.

[0023] Figure 3 A three-dimensional schematic diagram of the assembly relationship of each component of the torsion ring limiting structure of a tensile-bending-torsional multi-axial fatigue load loading structure is provided for the present application.

[0024] Figure 4A schematic diagram of the connection relationship between the I-beam, connecting clamp and bearing of the tensile-bending-torsional multi-axial fatigue load loading structure proposed in the present application;

[0025] Figure 5 A schematic diagram of the structure of the connecting clamp of the tensile-bending-torsional multi-axial fatigue load loading structure proposed in the present application.

[0026] In the figure: 1, I-shaped connecting rod; 2, actuator connecting lug; 3, connecting pin; 4, positioning lug; 5, connecting clamp; 6, ball bearing; 7, bearing base; 8, bearing cover plate; 9, universal ball joint; 10, placement base; 11, constraint frame; A, connecting section; B, shaft section; C, clamping section. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0028] As Figures 1-5 , the present application designs a tensile-bending-torsional multi-axial fatigue load loading structure, which comprises an I-shaped connecting rod 1. The webs at both ends of the I-beam connecting rod 1 are cut off and provided with positioning through holes on the side surfaces, allowing the connecting pin 3 to pass through and install the actuator connecting lug 2, which is used to connect the bending-torsional actuator. The bottom of the positioning lug 4 is provided with a threaded hole, which is adapted to the through hole in the middle of the I-beam 1, allowing the positioning lug 4 to be fixed on one side of the I-beam 1 by a bolt passing through. The positioning lug 4 is provided with a pin hole, which is used to connect a tensile actuator. The connecting clamp 5 is located at the center of the torsion ring, one end of which is connected to the I-shaped connecting rod 1 through a bolt, and the other end is fixed to the test piece through the pin hole and the constraint groove. The inner diameter of the ball bearing 6 is adapted to the middle shaft section of the connecting clamp 5. The bearing base 7 is provided as a thick square plate, the center of which is provided with a through hole allowing the connecting clamp 5 to pass through, and is provided with a groove adapted to the outer ring of the ball bearing 6, allowing the ball bearing 6 to be placed in the bearing base 7. The bearing cover plate 8 is connected to the bearing base 7 through a bolt, covering the ball bearing 6. The placement base 10 is a box-shaped body, which is used to support the bearing base 7 and lift it to a certain height to facilitate the installation of the test structure. The universal ball joint 9 is fixed to the two side surfaces of the bearing base 7 through a bolt. The constraint frame 11 is provided as a triangular steel and placed with one side of the constraint frame 11 close to the vertex of the universal ball joint on the ground, and then locked to the ground through foundation bolts. After the load transmission structure is built, the placement base 10 is removed before the experiment starts to avoid the influence of the placement base 10 on the upward and downward bending movements.

[0029] Reference Figures 1-2, the two actuators are connected by the I-shaped connecting rod 1 to realize the first step of load transmission, the ear-pin cooperation is formed by the design of the actuator connecting ear 2 and the connecting pin 3, the ear can rotate around the pin, and the problems of unstable bending and torsional load caused by the movement of the I-shaped connecting rod 1 and the radial load of the actuator cylinder can be solved. In the direction of tension loading, in order to ensure the stability of the tension loading and eliminate the problem of radial force caused by the up-down bending of the structure on the tension actuator, the positioning ear 4 and the pin are used to connect the tension actuator. The gap between the actuator connecting ear 2 and the I-shaped connecting rod 3 can eliminate the influence of the deformation of the clamp structure caused by the tension direction.

[0030] Reference Figure 1 , 3 -5, the ball bearing 6 is arranged, the mixed motion of torsion and bending can be separated by the movement separation of the inner and outer rings of the bearing, and the horizontal movement offset is limited by the constraint frame 11, so that the motion interference problem is solved. The connecting clamp 5 located at the center position is designed to be divided into three sections, which are the connecting section A connected with the I-shaped beam connecting rod 1, the shaft section B matched with the ball bearing 6 and the clamping section C for clamping and fixing the test piece. The connecting section A can transmit the load of the connecting rod transmission structure to the torsional ring limiting structure, and then transmit the load to the test piece by the connecting clamp 5. The bearing base 7 and the bearing cover plate 8 are arranged to fix and limit the ball bearing 6 in the shaft section, and the point-surface contact between the universal ball 9 on the left and right sides of the bearing base 7 and the constraint frame 11 forms the movement track of the up-down bending of the load transmission structure.

[0031] In the present application, reference Figures 1-2 , the structures of the test platform are installed in the above order during use, the connecting bolt position is screwed, and the placing base 10 is removed in time during formal test. The tension actuator is coaxial with the test piece and adopts the ear connection form, which will not affect the bending and torsional load. When the bending and torsional actuator loading is in the form of torque, the connecting clamp 5 takes the axis as the center to drive the test piece to twist, and the load transmission of torque is completed; when the bending and torsional actuator loading is in the form of bending moment, the torsional limiting structure moves up and down in the constraint frame 11 to drive the bending of the test piece, and the load transmission of bending moment is completed; when the bending and torsional actuator loading is in the form of bending moment and torque multi-axis loading, the inner ring of the ball bearing 6 cooperates with the connecting clamp to form torsional loading and deformation, and the outer ring drives the bearing base 7 to form bending loading and deformation in the constraint frame 11, so that the convenient switching of different loading modes is realized and the motion interference problem between different loads is solved.

[0032] Reference Figures 3-5 When different test pieces are tested, the clamping section C of the connecting clamp 5 needs to be designed according to the requirements of the test piece, and other structures do not need to be changed. Therefore, the load transmission structure is designed reasonably, and the replacement operation is convenient.

[0033] It should be noted that, referenceFigure 1 The standard parts used in the present application can be purchased from the market, including the universal ball joint 9 and the matched ball bearing 6, and the specific size and size of other special-shaped parts need to be designed according to the requirements of the test load and the test piece.

[0034] The various embodiments in the specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments. In particular, for the device embodiments, the above description is only the preferred embodiment of the present application, and since it is basically similar to the method embodiments, it is described more simply, and the relevant parts can be referred to the part of the method embodiments. The above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, and the changes or replacements within the technical range disclosed by the present application without departing from the principle of the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A stretch-bend-twist multiaxial fatigue load application structure, characterized by: The connecting rod transmission structure, the torsion ring limiting structure and the outer frame are included. The connecting rod transmission structure includes an I-shaped connecting rod (1), an actuator connecting lug (2), a connecting pin (3) and a positioning lug (4), the I-shaped connecting rod (1) is provided with a slot at both ends, the actuator connecting lug (2) is inserted into the slot, and the actuator connecting lug (2) is connected with a bending and torsion actuator; the I-shaped connecting rod (1) is provided with a through hole at both sides of the middle position, one side is provided with the positioning lug (4) connected with a tension actuator, and the other side is connected with the torsion ring limiting structure. The torsion ring limiting structure includes a connecting clamp (5), a ball bearing (6), a bearing base (7), a bearing cover plate (8) and a universal ball joint (9); the connecting clamp (5) includes a clamping section, a connecting section and a shaft section, the clamping section is connected with a test piece, the connecting section is connected with the I-shaped connecting rod (1), and the shaft section is matched with the ball bearing (6); the bearing base (7) is abutted on the outer frame through the universal ball joint (9) at both sides, the outer frame limits the torsion ring limiting structure to only bend up and down in the vertical plane, the bearing base (7) is provided with a groove matched with the outer ring of the ball bearing (6) in the inside, the ball bearing (6) is embedded in the groove, and the bearing cover plate (8) covers the ball bearing (6) in the bearing base (7); the bearing base (7) and the bearing cover plate (8) are provided with through holes in the centers, and the shaft section of the connecting clamp (5) passes through the through holes.

2. The stretch-bend-twist multiaxial fatigue load application structure according to claim 1, characterized in that: The outer frame includes a placing base (10) and a constraint frame (11), the placing base (10) is located directly below the torsion ring limiting structure, provides support for the torsion ring limiting structure, and is removed during the test; the constraint frame (11) is located on both sides of the bearing base (7) and is fixed to the ground through anchor bolts, the inner side of the constraint frame forms a point-face contact with the universal ball joint (9) on the bearing base (7), and the constraint frame limits the torsion ring limiting structure to bend up and down in the vertical plane and provides a track for the movement.

3. The multi-axial fatigue load application structure according to claim 2, characterized by: The actuator connecting lug (2) rotates around the connecting pin (3) as the center, the positioning lug (4) is connected with the tension actuator through the pin, the ball bearing (6) realizes the movement separation of bending and torsion, and the constraint frame (11) ensures that the bending direction is only in the vertical plane, so that the tension-bending moment-torsion three kinds of loads are jointly loaded and switched.

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