Inhaul cable stretching-bending combined loading experiment device capable of amplifying load under multi-boundary condition and using method thereof

Abstract

The invention discloses an inhaul cable stretching-bending combined loading experiment device capable of amplifying load under a multi-boundary condition and a using method thereof, and can be used in the field of inhaul cable tests. In actual engineering, the inhaul cable is usually subjected to axial tension and lateral constraint, is in a stretching-bending composite state and has a certain bending angle, and along with continuous increase of the engineering scale, the diameter of the inhaul cable and the tension borne by the inhaul cable are larger and larger. A full-size mechanical test is very difficult to carry out through a traditional horizontal inhaul cable tensile testing machine. A reaction wall, a reaction floor, a hydraulic actuator and a reaction buttress which are common in a structural laboratory are fully utilized, the inhaul cable stretching-bending composite loading device with multiple boundary conditions is designed, the bending angle can be adjusted, the output of the actuator can be amplified, stretching-bending composite loading of the inhaul cable can be achieved, the bending angle can be adjusted, and the application range of the inhaul cable stretching-bending composite loading device is widened. The load amplification factor is adjustable, the stress characteristics of the inhaul cable under the real service condition are represented, the force transmission path is clear, the reliability is high, and economy and practicability are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of cable testing, and in particular relates to a cable tension-bending composite loading experimental device capable of amplifying loads under multi-boundary conditions and a method for using the device. Background Art

[0002] In actual engineering, cables are often subjected to axial tension and lateral constraints, resulting in a combined tension-bending state with a certain bending angle. As the scale of projects continues to increase, the cable diameter and the tension it experiences also increase. Traditional horizontal cable tensile testing machines struggle to simulate the stress conditions of large cables with bending angles. Even if they can simulate the bending angle, eccentric loads can cause additional wear on the hydraulic cylinder.

[0003] The present invention makes full use of the reaction walls, reaction floors, hydraulic actuators and reaction piers commonly found in structural laboratories to design a cable tensioning-bending composite loading device with multiple boundary conditions, which can adjust the bending angle and amplify the actuator output. This device can realize tensioning-bending composite loading of large-tonnage cables, and has an adjustable bending angle and load amplification factor, reproducing the force characteristics of the cables under actual service conditions. It has a clear force transmission path, strong reliability, and is economical and practical. Summary of the Invention

[0004] The purpose of the present invention is to provide a cable tension-bending composite loading experimental device that can amplify the load under multiple boundary conditions and a method for using the same, in order to solve the technical problems of conventional loading devices at this stage, such as inconvenient loading, limited loading space, insufficient loading tonnage, inability to reproduce the actual boundary conditions of the cable, and easy wear of the loading equipment.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] According to the actual stress characteristics and boundary conditions of the cable, a pin shaft of appropriate diameter is selected, and then hydraulic actuators and reaction piers are arranged on the reaction wall and reaction floor according to the length and bending angle of the cable. The cable is installed, and the compound angle and size of the cable are adjusted after tightening, and then the test is started. A smaller tonnage hydraulic actuator can be used to effectively simulate the mechanical behavior characteristics of a large tonnage cable under real boundary conditions and bending angles.

[0007] The present invention proposes a cable tension-bending composite loading experimental device capable of amplifying loads under multi-boundary conditions, comprising a reaction wall (1), a reaction floor (2), a reaction pier (5), a reaction pier (9), a high-strength screw (10), a hydraulic actuator (3), a hydraulic actuator support and fixing device (11), a front ball joint (32), a rear ball joint (31), a load sensor (33), a saddle (6), a pin (61), a high-strength steel shaft (611), an anti-wear lining (612), a high-strength screw (51), a high-strength screw (91), a cable (4), an anchor head (41), an anchor head (42), a pin seat (7), a pin seat (8), a pin (81) and a pin (71).

[0008] The present invention can achieve large-tonnage loading of the cable with a smaller-tonnage actuator. The boundary conditions of the cable are more realistic, and the bending angle of the cable can be effectively simulated. It solves the technical problems of the current traditional loading devices, such as inconvenient loading, limited loading space, insufficient loading tonnage, inability to reproduce the real boundary conditions of the cable, and easy wear of the loading equipment. It is more economical and reasonable.

[0009] Since cables are usually not arranged in a straight line in actual engineering, there are usually lateral boundary constraints, which leads to a certain bending angle of the cables. As the strength and diameter of the cables increase, the load required for testing also increases. Conventional test equipment is difficult to meet the aforementioned test requirements.

[0010] According to the actual force characteristics, size and boundary conditions of the cable, a pin with a suitable diameter is selected. Then, according to the length and bending angle of the cable, the hydraulic actuator and reaction pier are arranged on the reaction wall and reaction floor. The cable is installed. After the cable is tightened, the angle and size are compounded and the test begins. The tension of the cable can be converted by the angle α, or the length L1 and L2. The tension of the cable is equal to the output of the hydraulic actuator divided by 2 times cosα, which is also equal to the output of the hydraulic actuator multiplied by 2 times the square root of L1 2 +L2 2 / L1, when the angle α is greater than 60° or L2 is greater than 1.732 times L1, the cable tension can be greater than the output of the hydraulic actuator, achieving load amplification and completing a large-tonnage cable tension test with a smaller-tonnage hydraulic actuator.

[0011] Compared with the existing devices, the present invention has the following characteristics and beneficial effects:

[0012] (1) The present invention has a simple structure, a concise processing technology, and each component is easy to obtain and assemble.

[0013] (2) Easy to install, economical and cost-effective.

[0014] (3) The force transmission path is clear, which facilitates force analysis.

[0015] (4) A larger cable tension can be achieved with a smaller force.

[0016] (5) It adopts electro-hydraulic servo control and has high loading accuracy.

[0017] (6) The real boundary conditions of the cable can be reproduced.

[0018] (7) The bending angle of the cable can be adjusted to reproduce the real situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic plan view of a cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to the present invention;

[0020] Figure 2 This is a side view of a cable tension-bending composite loading experimental device that can amplify loads under multiple boundary conditions;

[0021] Figure 3 It is a cross-sectional view of the pin 6 of the present invention.

[0022] Numbers in the figure: 1-reaction wall, 2-reaction floor, 5-reaction pier, 9-reaction pier, 10-high-strength screw, 3-hydraulic actuator, 11-hydraulic actuator support fixture, 32-front ball joint, 31-rear ball joint, 33-load sensor, 6-saddle, 61-pin, 611-high-strength steel shaft, 612-anti-wear lining, 51-high-strength screw, 91-high-strength screw, 4-cable, 41-anchor head, 42-anchor head, 7-pin seat, 8-pin seat, 81-pin and 71-pin. DETAILED DESCRIPTION

[0023] In order to make the technical means, innovative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below.

[0024] The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention. They are illustrative and exemplary and should not be construed as limiting the embodiments and scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the claims and the disclosure of the specification, including technical solutions that adopt any obvious substitutions and modifications to the embodiments described herein.

[0025] A cable tension-bending composite loading experimental device with amplified load under multiple boundary conditions, such as Figure 1 and 2As shown, it consists of the following components: 1-reaction wall, 2-reaction floor, 5-reaction pier, 9-reaction pier, 10-high-strength screw, 3-hydraulic actuator, 11-hydraulic actuator support fixture, 32-front ball joint, 31-rear ball joint, 33-load sensor, 6-saddle, 61-pin, 611-high-strength steel shaft, 612-anti-wear lining, 51-high-strength screw, 91-high-strength screw, 4-cable, 41-anchor head, 42-anchor head, 7-pin seat, 8-pin seat, 81-pin and 71-pin.

[0026] The reaction wall 1 is connected to the reaction floor 2 and is used to fix the hydraulic actuator 3; one end of the hydraulic actuator 3 is fixed to the reaction wall 1; the other end of the hydraulic actuator 3 pulls and connects the cable 4; the first reaction pier 5 and the second reaction pier 9 are fixed to the reaction floor 5 and are used to fix the two ends of the cable 4;

[0027] The tension of the cable 4 is adjusted by the output of the hydraulic actuator 3 to achieve load amplification.

[0028] Furthermore, the hydraulic actuator 3 has a front ball joint 32, a rear ball joint 31 and a load sensor 33. The presence of the front ball joint 32 and the rear ball joint 31 can ensure that the device is centered, release the end bending moment of the cable 4, and protect the piston and sealing components inside the hydraulic actuator.

[0029] Furthermore, the hydraulic actuator 3 is connected to the reaction wall 1 through the rear ball joint 31 and the high-strength screw 10, and a pre-tightening force is applied. The value of the pre-tightening force is greater than the load of the hydraulic actuator 3 itself displayed by the load sensor 33 on the hydraulic actuator 3 during the test, ensuring that the hydraulic actuator 3 is firmly installed and will not move.

[0030] Furthermore, a saddle 6 is installed on the front ball joint 31 of the hydraulic actuator 3, and a saddle pin 61 is provided on the saddle 6. By adjusting the diameter of the saddle pin 61, the contact arc surface of the cable 4 at the actual engineering saddle position can be simulated to ensure that the force boundary of the cable is real.

[0031] Furthermore, the first reaction pier 5 and the second reaction pier 9 are respectively connected to the reaction floor 2 through the first high-strength screw 51 and the second high-strength screw 91, and a pre-tightening force is applied. The friction force generated by the pre-tightening force is greater than the tension exerted on the cable 4, ensuring that the first reaction pier 5 and the second reaction pier 9 are firmly installed and will not move.

[0032] Furthermore, the ends of the cable 4 are both anchor head style, namely the first anchor head 41 and the second anchor head 42. The first anchor head 41 and the second anchor head 42 are connected to the first pin shaft seat 7 and the second pin shaft seat 8 through the first pin shaft 71 and the second pin shaft 81 respectively. The provision of the pin shaft can effectively release the lateral force and bending moment exerted on the cable 4, ensuring that the load is along the axial direction of the cable.

[0033] Furthermore, the tension of the cable 4 can be converted by the angle α, or the lengths L1 and L2, wherein the angle α is the angle formed by the length of the cable 4 between the saddle pin 61 and the first anchor head 41 and the vertical direction of the saddle pin 61. The first length L1 is the product of the length of the cable 4 between the saddle pin 61 and the first anchor head 41 and the cosine of the angle α; the second length L2 is the product of the length of the cable 4 between the saddle pin 61 and the first anchor head 41 and the sine of the angle α, and the length of the cable 4 between the saddle pin 61 and the first anchor head 41 is variable. The tension exerted on the cable 4 is equal to the reading of the load sensor 33 of the hydraulic actuator 3 when it is working divided by 2 times cosα, and is also equal to the output of the hydraulic actuator multiplied by 2 times the square root of L1 2 +L2 2 / L1; when the angle α is greater than 60° or L2 is greater than 1.732 times L1, the cable tension force can be greater than the output of the hydraulic actuator 3, thereby achieving load amplification and completing a large-tonnage cable tension test with a smaller-tonnage hydraulic actuator. Moreover, the hydraulic actuator acts strictly in an axial direction, and there is no lateral force, which will not cause additional wear on the device.

[0034] Furthermore, by adjusting the angle α, simulation of different bending angles of the cable can be achieved.

[0035] Furthermore, the positions of the first reaction pier 5, the second reaction pier 9, and the hydraulic actuator 3 can be modularly adjusted on the reaction wall 1 and the reaction floor 2 to meet the testing requirements of cables of any length and any bending angle.

[0036] Furthermore, if Figure 3 As shown, the interior of the saddle pin 61 is a high-strength steel shaft 611, and its surface is coated with an anti-wear lining 612 to prevent the cable from being damaged by friction during the stretching process.

[0037] Furthermore, the device further comprises a hydraulic actuator supporting and fixing device 11 , wherein the hydraulic actuator supporting and fixing device 11 is fixed on the reaction plate 2 and is used to fix the hydraulic actuator 3 .

[0038] In the device of the present invention, the reaction wall 1 is connected to the reaction floor 2 and is used to fix the hydraulic actuator 3; one end of the hydraulic actuator 3 is fixed on the reaction wall 1; the other end of the hydraulic actuator 3 pulls and connects the cable 4; the first reaction pier 5 and the second reaction pier 9 are fixed on the reaction floor 2 and are spaced at a certain distance, which can be adjusted according to actual experimental conditions, and are used to fix the two ends of the cable 4; the tension of the cable 4 is adjusted by the output of the hydraulic actuator 3 to achieve load amplification. The device of the present invention can achieve large-tonnage loading of the cable 4 with a smaller-tonnage hydraulic actuator 3. The boundary conditions of the cable 4 are more realistic, and the bending angle of the cable can be effectively simulated, solving the technical problems of inconvenient loading, limited loading space, insufficient loading tonnage, inability to reproduce the real boundary conditions of the cable, and easy wear of the loading equipment of the current traditional loading device, and is more economical and reasonable.

[0039] The present invention makes full use of reaction walls, reaction floors, hydraulic actuators and reaction piers to design a cable stretching-bending composite loading device with multiple boundary conditions, which can adjust the bending angle and amplify the actuator output. It can realize the stretching-bending composite loading of large-tonnage cables, and the bending angle and load amplification factor are adjustable, reproducing the force characteristics of the cables under actual service conditions, with a clear force transmission path, strong reliability, and economical and practical application.

[0040] The present invention also provides a method for using a cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions, comprising the following steps:

[0041] Step 1: According to the cable length, specifications, tonnage, bending angle and boundary conditions, combined with laboratory conditions, reasonably determine the installation position of each component.

[0042] Step 2: Fix the hydraulic actuator 3 to the reaction wall 1 through the high-strength screw 10, and complete the installation of the hydraulic actuator support and fixing device 11 at the bottom of the hydraulic actuator 3 so that the actuator is stably fixed on the reaction wall 1 and the reaction floor 2. The pre-tightening force of the high-strength screw 10 should be greater than the output of the actuator to ensure that the actuator is firmly installed.

[0043] Step 3: Install the saddle 6 on the front ball joint 32 of the hydraulic actuator 3, but do not insert the pin.

[0044] Step 4: The hydraulic actuator 3 is extended to its longest position.

[0045] Step 5: Fix the reaction pier 5 and the reaction pier 9 to the reaction floor 2 through high-strength screws 51 and high-strength screws 91 respectively, and apply pre-tightening force. The friction force generated by the pre-tightening force should be greater than the tension of the cable to ensure that the reaction pier 5 and the reaction pier 9 will not move.

[0046] Step 6: Install the pin seat 7 and the pin seat 8 on the reaction pier 5 and the reaction pier 9 respectively.

[0047] Step 7: Install the anchor head 41 of the cable 4 on the pin shaft seat 7 through the pin shaft 71.

[0048] Step 8: Install the anchor head 42 of the cable 4 on the pin shaft seat 8 through the pin shaft 81.

[0049] Step 9: Pass the cable 4 through the pin 61 and install it on the saddle 6.

[0050] Step 10: The hydraulic actuator 3 gradually tensions the cable 4 to a specified load.

[0051] Step 11. Measure the lengths L1 and L2, measure the angle α, check the installation dimensions, determine the test load and the output of the hydraulic actuator 3. The tension of the cable is equal to the output of the hydraulic actuator divided by 2 times cosα, which is also equal to the output of the hydraulic actuator multiplied by 2 times the square root of L1. 2 +L2 2 / L1.

[0052] Step 12: Start the experiment.

[0053] Step 13: After the test is completed, the hydraulic actuator 3 is extended to the longest position, and then the pins 61, 71 and 81 are pulled out, and the entire test piece is removed to complete the test piece removal.

[0054] Step 14: Carry out the test of the next specimen and repeat steps 1 to 13.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A cable tension-bending composite loading experimental device capable of amplifying loads under multi-boundary conditions, comprising a reaction wall (1), a reaction floor (2), a reaction pier (5), a reaction pier (9), a hydraulic actuator (3) and a hydraulic actuator support fixture (11), forming an internal force self-balancing system.

2. The cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to claim 1, characterized in that: The hydraulic actuator (3) has a front ball joint (32), a rear ball joint (31) and a load sensor (33). The presence of the front ball joint (32) and the rear ball joint (31) can ensure that the equipment is aligned, release the end bending moment, and protect the piston and sealing components inside the hydraulic actuator.

3. The cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to claim 1, characterized in that: The hydraulic actuator (3) is connected to the reaction wall (1) through the rear ball joint (31) and the high-strength screw (10), and a pre-tightening force is applied. The value of the pre-tightening force should be greater than the load displayed by the load sensor (33) on the hydraulic actuator (3) during the test to ensure that the hydraulic actuator (3) is firmly installed and will not move.

4. The cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to claim 1, characterized in that: A saddle (6) is mounted on the front ball joint (31) of the hydraulic actuator (3), and a pin (61) is mounted on the saddle (6). By adjusting the diameter of the pin (61), the contact arc surface of the cable (4) at the actual engineering saddle position can be simulated to ensure that the force boundary of the cable is real.

5. The cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to claim 1, characterized in that: The reaction pier (5) and the reaction pier (9) are connected to the reaction floor through high-strength screws (51) and high-strength screws (91) respectively, and a pre-tightening force is applied. The friction force generated by the pre-tightening force should be greater than the tension exerted on the cable (4), ensuring that the reaction pier (5) and the reaction pier (9) are firmly installed and will not move.

6. The cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to claim 5, characterized in that: The ends of the cable (4) are both anchor head style, namely anchor head (41) and anchor head (42). The anchor head (41) and anchor head (42) are connected to the pin shaft seat (8) and pin shaft seat (7) respectively through the pin shaft (81) and the pin shaft (71). The existence of the pin shaft can effectively release the lateral force and bending moment of the cable (4) and ensure that the load is along the axial direction of the cable.

7. The cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to claim 5, characterized in that: The tension of the cable (4) can be converted by the angle α, or the lengths L1 and L2. The tension of the cable is equal to the reading of the load sensor (33) of the hydraulic actuator (3) divided by 2 times cosα. When the angle α is greater than 60°, the tension of the cable can be greater than the output of the hydraulic actuator (3), thereby achieving load amplification. A large-tonnage cable tension test can be completed with a smaller-tonnage hydraulic actuator. Moreover, the hydraulic actuator strictly acts in an axial direction, and there is no lateral force, which will not cause additional wear of the equipment.

8. The cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to claim 1, characterized in that: The positions of the reaction pier (5), the reaction pier (9), and the hydraulic actuator (3) can be adjusted modularly on the reaction wall (1) and the reaction floor (2), and can adapt to the testing requirements of cables of any length and any bending angle.

9. The cable tension-bending composite loading experimental device capable of amplifying loads under multiple boundary conditions according to claim 4, characterized in that: The interior of the pin shaft (61) is a high-strength steel shaft (611), and the surface is provided with an anti-wear lining layer (612), which can prevent the cable from being damaged by friction during the stretching process.

10. A cable tension-bending composite loading test method capable of amplifying loads under multiple boundary conditions, characterized in that: The method is implemented by the device according to any one of claims 1 to 9, and the method comprises the following steps: S1. Determine the installation locations of each component based on the cable's length, specifications, tonnage, bending angle, and boundary conditions, combined with laboratory conditions. S2. Secure the hydraulic actuator to the reaction wall using high-strength screws. Install the support and fixing module below the hydraulic actuator. The preload force of the high-strength screws should be greater than the output force of the hydraulic actuator. S3. Install the saddle on the front ball joint of the hydraulic actuator. Extend the hydraulic actuator to its longest position. S4. The first reaction pier and the second reaction pier are fixed to the reaction floor by the first high-strength screw and the second high-strength screw, and a preload is applied. The friction force generated by the preload is greater than the tension of the cable; S5. The first anchor head of the cable is mounted on the first pin seat of the first reaction pier through the first pin, and the second anchor head of the cable is mounted on the second pin seat of the second reaction pier through the second pin; the hydraulic actuator gradually tightens the cable to the specified load; S6. Measure the first length of the cable between the saddle pin and the first anchor head, the second length between the saddle pin and the second anchor head, and the angle between the first length and the vertical direction of the saddle pin to determine the test load and the output of the hydraulic actuator; S7. Start the test; S8. After the test is completed, extend the hydraulic actuator to its longest position, then pull out the saddle pin, the first pin, and the second pin, and dismantle the entire device.

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