High-cable-force cable fatigue test equipment with separated perpetual motion load and test method

Abstract

The invention discloses a high-cable-force cable fatigue test device with separated perpetual motion load and a test method. The test device comprises a main body supporting part, a load loading part, a power part and a control part, wherein the main body supporting part is fixedly arranged on the working ground; the load loading part is fixedly arranged in the main body supporting part; the power part is fixedly arranged on the working ground around the main body supporting part; the control part is in communication connection with the power part through a communication line; the control part is used for regulating and controlling the power output by the power part so as to control the load loading part to respectively apply perpetual motion load to the cable test piece, so that the fatigue loading test is carried out on the cable test piece; and the load level and the energy consumption of the test equipment are obviously reduced in the process of carrying out a cable fatigue performance loading test according to national and industrial standards.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable performance testing, and more specifically, relates to a large-cable-force cable fatigue testing device and a testing method with constant and dynamic load separation. Background Art

[0002] In long-span bridge projects, the cable system plays a vital role. It is not only responsible for transmitting loads, but also supports the structure of the entire bridge deck. This system includes the main cables and suspenders of suspension bridges, and the cable-stayed cables of cable-stayed bridges. In addition, cable car main cables are also cable-type components. The loads borne by cables during use are not constant, but are constantly changing. This change may be caused by various factors such as the deadweight of the bridge itself, wind loads, and traffic loads. In addition, metal fatigue occurs in cables under repeated or cyclic stress loads. After the damage accumulates, it may eventually lead to the fracture of the material. Therefore, metal fatigue has an impact on the long-term safety of cables that cannot be ignored. For cable components, metal fatigue is particularly prominent because they bear constantly changing loads for a long time. Once fatigue fracture occurs in the cable, it may cause serious damage to the bridge structure and even endanger the safety of life and property.

[0003] In order to ensure the reliability of cable products and the safety of cable components, fatigue loading tests are usually required on sampled products before the cable product process changes or before mass production begins. These tests follow certain national or industry standards to verify the performance of materials, the stability of the process, and the reliability of production. Through fatigue tests, the durability of cable components can be evaluated and potential defects can be discovered in a timely manner, thereby ensuring the safety of life and property in bridge projects. The Chinese patent with the document number CN203758844U discloses a cable-stayed bridge fatigue testing machine, which vertically installs the cable specimen between the rigid crossbeam and the transverse rigid support of the frame, and sets a through-type pressure sensor to measure the initial pre-tension of the cable specimen, applies vertical vibration (large vertical stress) to the cable specimen by a vibration motor, applies a slight vertical displacement adjustment to the cable specimen by a stress amplitude adjustment device, feeds back the stress change of the cable specimen by a strain gauge equipped on the cable specimen, and controls the stress amplitude applied by the stress amplitude adjustment device according to the numerical values ​​fed back by the through-type pressure sensor and the strain gauge by a regulating controller. The cable-stayed bridge cable fatigue testing machine described in the Chinese patent with the document number CN203758844U can select a reasonable stress amplitude and stress amplitude spectrum according to different stress environments to conduct fatigue tests on cable specimens.

[0004] According to relevant standards, the cable fatigue test requires that the cable be tensioned to a certain level of constant load before a certain dynamic load is applied. For large-sized, high-strength cables for bridges, the maximum load during loading may exceed 1,000 tons, and the standard loading cycle is 2 million times, which is a great challenge to the capacity of the loading equipment. The stress size provided by the Chinese patent with document number CN203758844U is limited by the equipment and cannot meet the fatigue test requirements of large cable forces. Secondly, the direct use of loading actuators above 1,000 tons not only has high equipment costs, but also extremely high energy consumption during the test. In addition, when a tensioning cable that is not less than the tested cable is used to apply a constant load to the test cable, and then a dynamic load is applied through an actuator, the stiffness of the tensioning cable is very large, and the cable force change cannot be ignored. In fact, it is impossible to apply a constant load ideally, and the efficiency of the dynamic load applied by the actuator on the test cable is less than 50%. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a large-cable force cable fatigue testing equipment and a testing method with constant dynamic load separation, wherein the power output by the power component is regulated by the control component to control the load loading component to apply a constant dynamic load to the cable specimen fixed between the main support component and the load loading component, thereby performing a fatigue loading test on the cable specimen; through the precise regulation of the control component, the stability and consistency of the power output are ensured, so that in the process of conducting cable fatigue performance loading tests in accordance with national and industry standards, the load level and energy consumption of the testing equipment are significantly reduced, the average working efficiency of the testing equipment is improved, and the initial investment cost and operating cost are reduced. In addition, the flexibility of the testing equipment allows the test to adapt to different types of cable materials and structures, as well as different testing requirements, further reducing the investment cost.

[0006] In order to achieve the above-mentioned object, the present invention provides a large cable force fatigue test equipment with constant dynamic load separation, comprising: a main support component, a load loading component, a power component and a control component; wherein:

[0007] The main support component is fixedly mounted on the working ground, and comprises: a shock absorber base fixedly mounted on the working ground, and a reaction force frame fixedly mounted at the middle of the upper end of the shock absorber base; the reaction force frame comprises a first cross beam, a first longitudinal beam, a second cross beam and a second longitudinal beam, which are respectively fixedly connected end to end at both ends in sequence;

[0008] The load-applying component is fixedly arranged inside the main support component, and comprises: a limit device respectively fixedly arranged at the middle of the first longitudinal beam and the second longitudinal beam at one end facing each other, a third crossbeam whose two ends are respectively fixedly connected to a plurality of the limit devices by connecting bolts, a constant load actuator and a dynamic load actuator; a plurality of the constant load actuators are fixedly arranged between the second crossbeam and the third crossbeam with a mirror image symmetry of the cable specimen; a plurality of the dynamic load actuators are fixedly arranged between the first crossbeam and the third crossbeam with a mirror image symmetry of the cable specimen;

[0009] The power component is fixedly arranged on the working ground around the main support component, and includes: a high-pressure gas cylinder accumulator group fixedly arranged on the working ground at the front and rear sides of the shock absorber base in the mirror image of the center of the shock absorber base, a hydraulic oil source, a first hydraulic oil pipeline and a second hydraulic oil pipeline fixedly arranged on the working ground on the left side of the shock absorber base; the two ends of a plurality of the first hydraulic oil pipelines are respectively fixedly connected to the hydraulic oil source and a plurality of the dynamic load actuators; the two ends of a plurality of the second hydraulic oil pipelines are respectively fixedly connected to the hydraulic oil source and a plurality of the constant load actuators and a plurality of the high-pressure gas cylinder accumulator groups;

[0010] The control component is communicatively connected with the power component via a communication line, and includes a first electrically controlled valve fixedly arranged on the first hydraulic oil pipeline, a second electrically controlled valve fixedly arranged on the second hydraulic oil pipeline, and a controller communicatively connected with the first electrically controlled valve, the second electrically controlled valve and the hydraulic oil source; the power output by the power component is regulated by the control component to control the load-applying component to apply a constant dynamic load to the cable specimen respectively, thereby significantly reducing the load level and energy consumption of the test equipment.

[0011] Furthermore, the limiting device includes a support seat, a guide rail and a sliding member; a plurality of the support seats are symmetrically fixed at the middle of the opposite ends of the first longitudinal beam and the second longitudinal beam; the guide rail is fixed between the two support seats, and a plurality of the guide rails are respectively away from the first longitudinal beam and the second longitudinal beam by a certain distance; the sliding member is adapted to the guide rail and is movably connected to the guide rail.

[0012] Furthermore, the first cross beam, the first longitudinal beam, the second cross beam, the second longitudinal beam and the third cross beam are mainly composed of steel with a grade not lower than Q345 and are coated with anti-corrosion paint.

[0013] Furthermore, a plurality of the high-pressure gas cylinder accumulator groups are connected in series with a plurality of the adjacent constant load actuators through a plurality of the second hydraulic oil pipelines.

[0014] Another aspect of the present invention provides a large cable fatigue test method with constant and dynamic load separation, which is implemented using the test equipment as described above and includes the following steps:

[0015] S1: Check the working status of the test equipment to ensure that it meets the fatigue test design requirements of the cable specimen to be tested;

[0016] S2: Open the first electrically controlled valve and the second electrically controlled valve, take the constant load actuator as the active one and the dynamic load actuator as the passive one, and use the displacement loading mode to push the third beam to a position suitable for installing the cable specimen;

[0017] S3: After the cable specimen is installed, a number of the constant load actuators are used as active and a number of the dynamic load actuators are used as passive, and the cable specimen is slightly tensioned using a displacement loading mode to eliminate the idle travel between the structures and mechanisms. At this time, the cable specimen is in a completely unloaded state;

[0018] S4: maintaining the states of the first electrically controlled valve and the second electrically controlled valve unchanged, taking a number of the constant load actuators as the active ones and a number of the dynamic load actuators as the slave ones, and moving the pistons of a number of the constant load actuators forward to push the third beam to tension the cable specimen to a balanced state. During the tensioning process, hydraulic oil enters into a number of high-pressure gas cylinder accumulator groups respectively, and the hydraulic pressure and the gas pressure are balanced with each other;

[0019] S5: After reaching a balanced state, the second electrically controlled valve is closed. At this time, the hydraulic oil in the second hydraulic oil pipeline flows in the pipeline between the plurality of constant load actuators and the plurality of high-pressure gas cylinder accumulator groups, and is not affected by the hydraulic oil source; the plurality of dynamic load actuators are active, the plurality of constant load actuators are driven, and the thrust of the plurality of constant load actuators is maintained by air springs through the plurality of high-pressure gas cylinder accumulator groups, so as to push the third crossbeam to reciprocate on both sides of the balanced position in step S4, and load fatigue load on the cable specimen;

[0020] S6: During the fatigue loading stage in step S5, the control component periodically opens the second electronically controlled valve to compensate the energy loss caused by internal friction of the constant load operating system mainly composed of a plurality of the constant load actuators and a plurality of the high-pressure gas cylinder accumulator groups through the hydraulic oil source;

[0021] S7: after the standard loading cycle is met, repeat step S2, remove the cable specimen, check that the test equipment is in normal condition, and then perform subsequent fatigue tests on the cable specimen.

[0022] Furthermore, in step S3, when the cable specimen is in a completely unloaded state, a pre-applied air pressure p=p0 is applied in some of the high-pressure gas cylinder accumulator groups, the internal high-pressure air volume change ΔV is 0, the load T of some of the constant load actuators is 0, the load t of some of the dynamic load actuators is 0, and the cable specimen length change ΔL is 0.

[0023] Furthermore, in step S4, when the cable specimen reaches a balanced state, the high-pressure air inside the high-pressure gas cylinder accumulator group is further compressed by the hydraulic oil, and there is a negative volume change ΔV=-ΔV0, and the air pressure has an increment p=p0+Δp; the load T=T0 of the constant load actuators, and the value of T0 is equal to the value of the balanced load; the load t of the dynamic load actuators is 0; the cable specimen is stretched and lengthened, and the length change ΔL=ΔL0, and the equilibrium relationship is established at this time:

[0024] kΔL0=T0=A(p0+Δp)

[0025] Wherein, k is the tensile stiffness of the cable specimen, and A is the total effective area of ​​the hydraulic oil in the constant load actuators.

[0026] Further, in step S5, when the cable specimen is further loaded and stretched in a relative equilibrium state, the pistons of some of the dynamic load actuators retreat, and the load is a tensile force t=δt; the cable specimen is stretched and elongated compared to the equilibrium state, and the length change ΔL=ΔL0+δL; the pistons of some of the constant load actuators passively advance, and the negative pressure sucks the hydraulic oil out of some of the high-pressure gas cylinder accumulator groups respectively, and the hydraulic oil extrusion of the high-pressure air inside is reduced, and there is a relatively positive volume change, ΔV=-(ΔV0-δV), and the air pressure has a negative increment, p=p0+Δp-δp; the load T of some of the constant load actuators has a negative increment due to the change of the air pressure of some of the high-pressure gas cylinder accumulator groups, T=T0-δT, and the equilibrium relationship established at this time is:

[0027] k(ΔL0+δL)=T0-δT+δt=A(p0+Δp-δp)+δt

[0028] Wherein, k is the tensile stiffness of the cable specimen, and A is the total effective area of ​​the hydraulic oil in the constant load actuators.

[0029] Further, in step S5, when the cable specimen is further loaded and shortened in the relative equilibrium state, the pistons of several dynamic load actuators advance, and the load is a tensile force t=-δt; the cable specimen is shortened compared to the equilibrium state, and the length change ΔL=ΔL0-δL; the pistons of several constant load actuators passively retreat, and the hydraulic oil is pressed from several second hydraulic oil pipelines into several high-pressure gas cylinder accumulator groups respectively, and the hydraulic oil extrusion of the high-pressure air inside increases, and there is a relatively negative volume change, ΔV=-(ΔV0+δV), and the air pressure has a positive increment, p=p0+Δp+δp; the load T of several constant load actuators has a positive increment due to the change of the air pressure of several first accumulator groups, T=T0+δT, and the equilibrium relationship established at this time is:

[0030] k(ΔL0-δL)=T0+δT-δt=A(p0+Δp+δp)-δt

[0031] Wherein, k is the tensile stiffness of the cable specimen, and A is the total effective area of ​​the hydraulic oil in the constant load actuators.

[0032] Furthermore, in step S6, the load of the dynamic load actuators in a single fatigue loading cycle is obtained as 2δt from the balance relationship between the loading stretch and the loading shortening, and:

[0033] 2δt=2kδL+2Aδp

[0034] Among them, k is the tensile stiffness of the cable specimen, A is the total effective area of ​​the hydraulic oil in the constant load actuators, 2kδL is the fatigue load amplitude required by the test scheme within a single fatigue loading cycle, and 2Aδp is the compensation for the fluctuation of the constant load operating system within a single fatigue loading cycle.

[0035] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0036] 1. The test equipment of the present invention adjusts the power output by the power component through the control component, so as to control the load-applying component to apply a constant dynamic load to the cable specimen fixed between the main support component and the load-applying component, thereby performing a fatigue loading test on the cable specimen; through the precise regulation of the control component, the stability and consistency of the power output are ensured, so that in the process of carrying out the cable fatigue performance loading test in accordance with national and industry standards, the load level and energy consumption of the test equipment are significantly reduced, the average working efficiency of the test equipment is improved, and the initial investment cost and operating cost are reduced. In addition, the flexibility of the test equipment allows the test to adapt to different types of cable materials and structures, as well as different testing requirements, further reducing the investment cost.

[0037] 2. The test equipment of the present invention regulates the first electrically controlled valve, the second electrically controlled valve and the hydraulic oil source through the controller, and at the same time, separates the constant load actuator and the dynamic load actuator through the third crossbeam, the first hydraulic oil pipeline and the second hydraulic oil pipeline, so that a plurality of the constant load actuators and a plurality of the dynamic load actuators respectively apply loads to the cable specimen using a force loading mode or a displacement loading mode, and a smaller dynamic load portion is borne by a plurality of the dynamic load actuators, and a larger constant load portion is borne by a low-energy actuation system composed of a plurality of the constant load actuators and the first accumulator group and the second accumulator group, thereby improving the working efficiency of the entire test equipment, significantly reducing the load level and energy consumption of the fatigue loading equipment, and reducing the initial investment cost and operating cost.

[0038] 3. The test equipment of the present invention improves the wear resistance of the contact surface, increases the service life of the limit device, and ensures the safety of the test by processing the contact surface between the guide rail and the sliding part through heat treatment, surface hardening or coating treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of a test device according to an embodiment of the present invention;

[0040] Figure 2 This is a structural schematic diagram of the hydraulic oil circuit connection of an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of the steps of the test method of an embodiment of the present invention;

[0042] Figure 4 It is a schematic diagram of force analysis of a cable specimen and a test device when the cable specimen is in a completely unloaded state according to an embodiment of the present invention;

[0043] Figure 5 It is a schematic diagram of force analysis of a cable specimen and a test device when the cable specimen is in a balanced state according to an embodiment of the present invention;

[0044] Figure 6 It is a schematic diagram of force analysis of a cable specimen and a test device when the cable specimen is loaded and stretched according to an embodiment of the present invention;

[0045] Figure 7 It is a schematic diagram of force analysis of a cable specimen and a test device when the cable specimen is loaded and shortened according to an embodiment of the present invention.

[0046] In all the drawings, the same figure marks represent the same technical features, specifically: 1-cable specimen, 2-shock absorber base, 31-first crossbeam, 32-first longitudinal beam, 33-second crossbeam, 34-second longitudinal beam, 4-limiting device, 41-support seat, 42-guide rail, 43-sliding member, 5-third crossbeam, 6-constant load actuator, 7-dynamic load actuator, 8-high-pressure gas cylinder accumulator group, 9-hydraulic oil source, 10-first hydraulic oil pipeline, 11-second hydraulic oil pipeline. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] Example 1

[0049] like Figure 1 and Figure 2 As shown, Example 1 of the present application provides a large cable fatigue test equipment with constant dynamic load separation, including: a main body support component, a load loading component, a power component and a control component; wherein the main body support component is fixed on the working ground; the load loading component is fixed inside the main body support component; the power component is fixed on the working ground around the main body support component; the control component is communicatively connected with the power component through a communication line; in the actual test process, the power output of the power component is regulated by the control component to control the load loading component to apply a constant dynamic load to the cable specimen 1 fixed between the main body support component and the load loading component, thereby performing a fatigue loading test on the cable specimen 1; through the precise regulation of the control component, the stability and consistency of the power output are ensured, so that in the process of carrying out cable fatigue performance loading tests in accordance with national and industry standards, the load level and energy consumption of the test equipment are significantly reduced, the average working efficiency of the test equipment is improved, and the initial investment cost and operating cost are reduced. In addition, the flexibility of the test equipment allows the test to adapt to different types of cable materials and structures, as well as different testing requirements, further reducing the investment cost.

[0050] Specifically, Figure 1 and Figure 2 As shown, the main support component is fixed on the working ground to support other components, which includes: a shock absorbing base 2 and a reaction force frame;

[0051] The shock absorbing base 2 is fixed on the working ground to stably support other components and ensure the stability of the entire test equipment during the test;

[0052] Preferably, the shock absorbing base 2 is stably and fixedly connected to the working ground through a force transmission embedded part;

[0053] In an optional embodiment, the upper surface of the shock absorber base 2 is fixedly provided with a plurality of evenly parallel grooves for stably fixing the reaction frame;

[0054] The reaction frame is fixedly arranged at the middle of the upper end of the shock absorber base 2, and is used to stably support other components, and includes: a first cross beam 31, a first longitudinal beam 32, a second cross beam 33 and a second longitudinal beam 34;

[0055] The first cross beam 31 is fixedly arranged on the left side of the middle part of the upper end of the shock absorber base 2;

[0056] The first longitudinal beam 32 is fixedly arranged at the rear side of the middle part of the upper end of the shock absorber base 2;

[0057] The second cross beam 33 is fixedly arranged on the right side of the middle part of the upper end of the shock absorber base 2, and a through hole adapted to the cable specimen 1 is fixedly arranged in the middle part thereof;

[0058] The second longitudinal beam 34 is fixedly arranged at the front side of the middle part of the upper end of the shock absorber base 2;

[0059] Preferably, the first cross beam 31, the first longitudinal beam 32, the second cross beam 33 and the second longitudinal beam 34 are respectively fixedly connected end to end in sequence;

[0060] Preferably, the first cross beam 31, the first longitudinal beam 32, the second cross beam 33 and the second longitudinal beam 34 are mainly composed of steel with a grade not lower than Q345, and are coated with anti-corrosion paint. The color of the anti-corrosion paint can be customized according to user requirements.

[0061] Specifically, Figure 1 and Figure 2 As shown, the load loading component is fixedly arranged inside the main support component, and is used to load the cable specimen 1 with a constant dynamic load, and includes a limit device 4, a third crossbeam 5, a constant load actuator 6 and a dynamic load actuator 7;

[0062] The plurality of limit devices 4 are respectively fixedly arranged at the middle of the first longitudinal beam 32 and the second longitudinal beam 34 facing each other, and include a support seat 41, a guide rail 42 and a sliding member 43;

[0063] A plurality of the support seats 41 are symmetrically fixedly disposed at the middle portions of the first longitudinal beam 32 and the second longitudinal beam 34 at the opposite ends thereof;

[0064] Preferably, the support seat 41 includes a support seat such as a triangular support seat or a circular support seat;

[0065] The guide rail 42 is fixedly disposed between the two support seats 41;

[0066] Preferably, the plurality of guide rails 42 are respectively separated from the first longitudinal beam 32 and the second longitudinal beam 34 by a distance;

[0067] The sliding member 43 is adapted to the guide rail 42 and is movably connected to the guide rail 42;

[0068] Preferably, the contact surface between the guide rail 42 and the sliding member 43 is processed by a processing method including heat treatment, surface hardening or coating treatment, so as to improve the wear resistance of the contact surface, increase the service life of the limit device 4, and ensure the safety of the test;

[0069] Both ends of the third cross beam 5 are fixedly connected to the plurality of sliding members 43 in the plurality of limit devices 4 by connecting bolts respectively;

[0070] Preferably, the third cross beam 5 is mainly composed of steel with a grade not lower than Q345 and is coated with anti-corrosion paint;

[0071] Preferably, a through hole adapted to the cable specimen 1 is fixedly provided in the middle of the third cross beam 5;

[0072] Preferably, the two ends of the cable specimen 1 pass through the middle through holes of the second cross beam 33 and the third cross beam 5 respectively, and are stably fixed inside the test equipment by anchor heads and reinforcing washers fixedly sleeved on the outer sides of the two ends of the cable specimen 1;

[0073] Preferably, the cable specimen 1 comprises parallel steel wire cables or steel strand cables such as main cable strands of a suspension bridge, sling cables of a suspension bridge, stay cables of a cable-stayed bridge, suspenders of a cable-arch bridge, and cable car cables;

[0074] A plurality of the constant load actuators 6 are fixedly disposed between the second cross beam 33 and the third cross beam 5 in a mirror-symmetrical manner with the cable specimen 1, and are fixedly connected to the second cross beam 33 and the third cross beam 5 respectively by connecting bolts;

[0075] A plurality of the dynamic load actuators 7 are fixedly disposed between the first cross beam 31 and the third cross beam 5 in a mirror-symmetrical manner with the cable specimen 1, and are fixedly connected to the first cross beam 31 and the third cross beam 5 respectively by connecting bolts;

[0076] Specifically, Figure 1 and Figure 2 As shown, the power component is fixedly arranged on the working ground around the main support component, and is used to provide the power for the load-applying component to apply the load to the cable specimen 1, and includes: a high-pressure gas cylinder accumulator group 8, a hydraulic oil source 9, a first hydraulic oil pipeline 10 and a second hydraulic oil pipeline 11;

[0077] The plurality of high-pressure gas cylinder accumulator groups 8 are respectively fixed on the front and rear working surfaces of the shock absorber base 2 with the center mirror image of the shock absorber base 2, and are mainly composed of a plurality of high-pressure gas cylinder accumulators connected in parallel;

[0078] The hydraulic oil source 9 is fixedly arranged on the working ground on the left side of the shock absorber base 2, and a plurality of hydraulic oil pumps and hydraulic oil tanks are fixedly arranged inside the hydraulic oil source 9, which are used to provide the load-applying component with power to apply the load to the cable specimen 1;

[0079] Two ends of the plurality of first hydraulic oil pipelines 10 are respectively fixedly connected to the hydraulic oil source 9 and the plurality of dynamic load actuators 7;

[0080] Both ends of the plurality of second hydraulic oil pipelines 11 are respectively fixedly connected to the hydraulic oil source 9 and the plurality of constant load actuators 6 and the plurality of high-pressure gas cylinder accumulator groups 8;

[0081] Preferably, the plurality of high-pressure gas cylinder accumulator groups 8 are respectively connected in series with the plurality of adjacent constant load actuators 6 through the plurality of the second hydraulic oil pipelines 11, and form a constant load operation system;

[0082] Preferably, the middle section of the second hydraulic oil pipeline 11 is fixed to the working ground in front of the shock absorber base 2 through a bracket;

[0083] Specifically, Figure 1 and Figure 2 As shown, the control component is fixedly arranged on one side of the main support component and is connected to the power component through a communication line for regulating the test process, and includes: a first electric control valve, a second electric control valve and a controller;

[0084] The first electrically controlled valve is fixedly mounted on the first hydraulic oil pipeline 10 and is located on the left side of the shock absorber base 2, and can open or cut off the oil supply pipelines to the plurality of dynamic load actuators 7 according to different working conditions;

[0085] The second electrically controlled valve is fixedly mounted on the second hydraulic oil pipeline 11 and is located on the left side of the shock absorber base 2, and can open or cut off the oil supply pipelines to the plurality of constant load actuators 6 and the plurality of high-pressure gas cylinder accumulator groups 8 according to different working conditions;

[0086] The controller is in communication with the first electrically controlled valve, the second electrically controlled valve and the hydraulic oil source 9, and is used to control the test process;

[0087] During the fatigue test, the first electrically controlled valve, the second electrically controlled valve and the hydraulic oil source 9 are regulated by the controller. Meanwhile, the constant load actuator 6 and the dynamic load actuator 7 are separated by the third crossbeam 5, the first hydraulic oil pipeline 10 and the second hydraulic oil pipeline 11, so that a plurality of the constant load actuators 6 and a plurality of the dynamic load actuators 7 respectively apply loads to the cable specimen 1 in a force loading mode or a displacement loading mode, and a smaller dynamic load portion is borne by a plurality of the dynamic load actuators 7, and a larger constant load portion is borne by a constant load actuation system composed of a plurality of the constant load actuators 6 and a plurality of the high-pressure gas cylinder accumulator groups 8, thereby improving the working efficiency of the entire test equipment, significantly reducing the load level and energy consumption of the fatigue loading equipment, and reducing the initial investment cost and operating cost;

[0088] Preferably, the main energy consumption of the constant load operation system composed of the plurality of constant load actuators 6 and the high-pressure gas cylinder accumulator group 8 is to compensate for the energy consumption generated by friction in the system;

[0089] Example 2

[0090] like Figures 1 to 7As shown, based on the above-mentioned embodiment 1, embodiment 2 of the present application provides a large cable fatigue test method with constant dynamic load separation, including the following steps:

[0091] S1: Check the working status of the test equipment to ensure that it meets the fatigue test design requirements of the cable specimen 1 to be tested;

[0092] S2: Open the first electrically controlled valve and the second electrically controlled valve, use a plurality of constant load actuators 6 as active actuators and a plurality of dynamic load actuators 7 as passive actuators, and use a displacement loading mode to push the third beam 5 to a position suitable for installing the cable test piece 1;

[0093] S3: After the cable specimen 1 is installed, the cable specimen 1 is slightly tensioned in a displacement loading mode with a plurality of the constant load actuators 6 as active and a plurality of the dynamic load actuators 7 as passive, to eliminate the idle travel between the structures and mechanisms. At this time, the cable specimen 1 is in a completely unloaded state;

[0094] S4: Maintaining the states of the first electrically controlled valve and the second electrically controlled valve unchanged, with the plurality of constant load actuators 6 as the active ones and the plurality of dynamic load actuators 7 as the passive ones, the pistons of the plurality of constant load actuators 6 move forward to push the third crossbeam 5 to tension the cable specimen 1 to a balanced state. During the tensioning process, the hydraulic oil respectively enters the plurality of high-pressure gas cylinder accumulator groups 8, and the hydraulic pressure and the gas pressure are balanced with each other;

[0095] S5: After reaching the equilibrium state, the second electrically controlled valve is closed. At this time, the hydraulic oil in the second hydraulic oil pipeline 11 flows in the pipeline between the plurality of constant load actuators 6 and the plurality of high-pressure gas cylinder accumulator groups 8, and is not affected by the hydraulic oil source 9; the plurality of dynamic load actuators 7 are active, the plurality of constant load actuators 6 are driven, and the thrust of the plurality of constant load actuators 6 is maintained by the air springs of the plurality of high-pressure gas cylinder accumulator groups 8, so as to push the third crossbeam 5 to reciprocate on both sides of the equilibrium position in step S4, and load the fatigue load on the cable specimen 1;

[0096] S6: During the fatigue loading stage in step S5, the control component periodically opens the second electrically controlled valve to compensate the energy loss caused by internal friction of the constant load operating system mainly composed of the plurality of constant load actuators 6 and the plurality of high-pressure gas cylinder accumulator groups 8 through the hydraulic oil source 9;

[0097] S7: after the standard loading cycle is met, step S2 is repeated, the cable specimen 1 is removed, and after checking that the test equipment is in normal condition, subsequent fatigue tests of the cable specimen 1 are performed.

[0098] Preferably, in step S3, when the cable specimen 1 is in a completely unloaded state, the force analysis of the cable specimen 1 and the test equipment is as follows: Figure 4 As shown, some of the high-pressure gas cylinder accumulator groups 8 have a pre-applied gas pressure p=p0, the internal high-pressure air volume change ΔV is 0, the load T of some of the constant load actuators 6 is 0, the load t of some of the dynamic load actuators 7 is 0, and the length change ΔL of the cable specimen 1 is 0;

[0099] Preferably, the balance load is calculated according to the upper and lower limits of fatigue load determined by relevant national standards, industry standards or negotiation, and the value of the balance load is (upper limit of load + lower limit of load) / 2;

[0100] Preferably, in step S4, when the cable specimen 1 reaches a balanced state, the force analysis of the cable specimen 1 and the test equipment is as follows: Figure 5 As shown, the high-pressure air inside the high-pressure gas cylinder accumulator group 8 is further compressed by the hydraulic oil, and there is a negative volume change ΔV=-ΔV0, and the air pressure has an increment p=p0+Δp; the load T of the constant load actuator 6 is T=T0, and the value of T0 is equal to the value of the balanced load; the load t of the dynamic load actuator 7 is 0; the cable specimen 1 is stretched and lengthened, and the length change ΔL=ΔL0, and the equilibrium relationship is established at this time:

[0101] kΔL0=T0=A(p0+Δp)

[0102] Wherein, k is the tensile stiffness of the cable specimen 1, and A is the total action area of ​​the hydraulic oil in the constant load actuators 6;

[0103] Preferably, in step S5, when the cable specimen 1 is further loaded and stretched in a relatively balanced state, the force analysis of the cable specimen 1 and the test equipment is as follows: Figure 6 As shown; the pistons of some of the dynamic load actuators 7 retreat, and the load is a tensile force t=δt; the cable specimen 1 is stretched and elongated compared to the equilibrium state, and the length change ΔL=ΔL0+δL; the pistons of some of the constant load actuators 6 passively advance, and the negative pressure sucks the hydraulic oil out of some of the high-pressure gas cylinder accumulator groups 8, and the hydraulic oil extrusion of the high-pressure air inside is reduced, and there is a relatively positive volume change, ΔV=-(ΔV0-δV), and the air pressure has a negative increment, p=p0+Δp-δp; the load T of some of the constant load actuators 6 has a negative increment due to the change of the air pressure of some of the high-pressure gas cylinder accumulator groups 8, T=T0-δT, and the equilibrium relationship is established at this time:

[0104] k(ΔL0+δL)=T0-δT+δt=A(p0+Δp-δp)+δt

[0105] Wherein, k is the tensile stiffness of the cable specimen 1, and A is the total action area of ​​the hydraulic oil in the constant load actuators 6;

[0106] Preferably, in step S5, when the cable specimen 1 is further loaded and shortened in a relatively balanced state, the force analysis of the cable specimen 1 and the test equipment is as follows: Figure 7 As shown; the pistons of some of the dynamic load actuators 7 move forward, and the load is a tensile force t=-δt; the cable specimen 1 is shortened compared to the equilibrium state, and the length change ΔL=ΔL0-δL; the pistons of some of the constant load actuators 6 passively retreat, and the hydraulic oil is pressed from some of the second hydraulic oil pipelines 11 into some of the high-pressure gas cylinder accumulator groups 8, and the hydraulic oil extrusion of the high-pressure air inside increases, and there is a relatively negative volume change, ΔV=-(ΔV0+δV), and the air pressure has a positive increment, p=p0+Δp+δp; the load T of some of the constant load actuators 6 has a positive increment due to the change of the air pressure of some of the high-pressure gas cylinder accumulator groups 8, T=T0+δT, and the equilibrium relationship is established at this time:

[0107] k(ΔL0-δL)=T0+δT-δt=A(p0+Δp+δp)-δt

[0108] Wherein, k is the tensile stiffness of the cable specimen 1, and A is the total action area of ​​the hydraulic oil in the constant load actuators 6;

[0109] Preferably, in step S6, the load of the dynamic load actuators 7 in a single fatigue loading cycle is obtained as 2δt from the balance relationship between the loading stretch and the loading shortening, and:

[0110] 2δt=2kδL+2Aδp

[0111] Preferably, during the fatigue loading process of the cable specimen 1, the total load 2δt borne by the plurality of dynamic load actuators 7 is equal to the fatigue load amplitude 2kδL required by the test plan plus the compensation 2Aδp for the fluctuation of the constant load operating system mainly composed of the plurality of constant load actuators 6 and the plurality of high-pressure gas cylinder accumulator groups 8, and since the air compression modulus is extremely small, it can be considered that the constant load fluctuation 2Aδp≈0 caused by the volume change of high-pressure air, thereby improving the average working efficiency of the test equipment, reducing energy consumption, and reducing test costs.

[0112] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0113] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0114] In this patent, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, the elements defined by the sentence "includes..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Those skilled in the art will readily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A large cable fatigue test equipment with constant and dynamic load separation, characterized in that: include: Main support components, load loading components, power components and control components; among which: The main body support component is fixedly mounted on the working ground, and comprises: a shock absorber base (2) fixedly mounted on the working ground, and a reaction force frame fixedly mounted on the middle part of the upper end of the shock absorber base (2); the reaction force frame comprises a first cross beam (31), a first longitudinal beam (32), a second cross beam (33), and a second longitudinal beam (34) which are respectively fixedly connected end to end in sequence at both ends; The load-applying component is fixedly arranged inside the main support component, and comprises: a limiting device (4) fixedly arranged at the middle of the first longitudinal beam (32) and the second longitudinal beam (34) at the opposite ends, a third crossbeam (5) whose two ends are fixedly connected to a plurality of the limiting devices (4) by connecting bolts, a constant load actuator (6) and a dynamic load actuator (7); a plurality of the constant load actuators (6) are fixedly arranged between the second crossbeam (33) and the third crossbeam (5) in a mirror-symmetrical manner with the cable specimen (1); a plurality of the dynamic load actuators (7) are fixedly arranged between the first crossbeam (31) and the third crossbeam (5) in a mirror-symmetrical manner with the cable specimen (1); The power component is fixedly arranged on the working ground around the main support component, and comprises: a high-pressure gas cylinder accumulator group (8) fixedly arranged on the working ground at the front and rear sides of the shock absorber base (2) in the mirror image of the center of the shock absorber base (2), a hydraulic oil source (9) fixedly arranged on the working ground on the left side of the shock absorber base (2), a first hydraulic oil pipeline (10) and a second hydraulic oil pipeline (11); the two ends of a plurality of the first hydraulic oil pipelines (10) are respectively fixedly connected to the hydraulic oil source (9) and the plurality of the dynamic load actuators (7); the two ends of a plurality of the second hydraulic oil pipelines (11) are respectively fixedly connected to the hydraulic oil source (9) and the plurality of the constant load actuators (6) and the plurality of the high-pressure gas cylinder accumulator groups (8); The control component is connected to the power component for communication via a communication line, and includes a first electrically controlled valve fixedly arranged on the first hydraulic oil pipeline (10), a second electrically controlled valve fixedly arranged on the second hydraulic oil pipeline (11), and a controller connected to the first electrically controlled valve, the second electrically controlled valve and the hydraulic oil source (9); the power output by the power component is regulated by the control component to control the load-applying component to apply a constant dynamic load to the cable specimen (1), thereby significantly reducing the load level and energy consumption of the test equipment.

2. The test device according to claim 1, characterized in that The limiting device (4) comprises a support seat (41), a guide rail (42) and a sliding member (43); a plurality of the support seats (41) are symmetrically fixed at the middle of the first longitudinal beam (32) and the second longitudinal beam (34) at the opposite ends; the guide rail (42) is fixed between the two support seats (41), and a plurality of the guide rails (42) are respectively separated from the first longitudinal beam (32) and the second longitudinal beam (34) by a certain distance; the sliding member (43) is adapted to the guide rail (42) and is movably connected to the guide rail (42).

3. The test device according to claim 1, characterized in that: The first cross beam (31), the first longitudinal beam (32), the second cross beam (33), the second longitudinal beam (34) and the third cross beam (5) are mainly composed of steel with a grade not lower than Q345 and are coated with anti-corrosion paint.

4. The test device according to any one of claims 1 to 3, characterized in that The plurality of high-pressure gas cylinder accumulator groups (8) are respectively connected in series with the plurality of adjacent constant load actuators (6) via the plurality of the second hydraulic oil pipelines (11).

5. A large cable fatigue test method with constant and dynamic load separation, implemented by using the test equipment as described in any one of claims 1 to 4, characterized in that: The steps include: S1: Check the working status of the test equipment to ensure that it meets the fatigue test design requirements of the cable specimen to be tested (1); S2: Open the first electrically controlled valve and the second electrically controlled valve, with the constant load actuator (6) as the active actuator and the dynamic load actuator (7) as the passive actuator, and use the displacement loading mode to push the third beam (5) to a position suitable for installing the cable test piece (1); S3: After the cable specimen (1) is installed, a plurality of the constant load actuators (6) are used as active actuators, and a plurality of the dynamic load actuators (7) are used as passive actuators, and the cable specimen (1) is slightly tensioned using a displacement loading mode to eliminate idle travel between various structures and mechanisms. At this time, the cable specimen (1) is in a completely unloaded state; S4: The states of the first electrically controlled valve and the second electrically controlled valve are maintained unchanged, with a plurality of the constant load actuators (6) being active and a plurality of the dynamic load actuators (7) being passive, and the pistons of the plurality of the constant load actuators (6) moving forward to push the third crossbeam (5) to tension the cable specimen (1) to a balanced state. During the tensioning process, hydraulic oil respectively enters into a plurality of high-pressure gas cylinder accumulator groups (8), and the hydraulic pressure and the gas pressure are balanced with each other; S5: After reaching a balanced state, the second electrically controlled valve is closed, and at this time, the hydraulic oil in the second hydraulic oil pipeline (11) flows in the pipeline between the plurality of constant load actuators (6) and the plurality of high-pressure gas cylinder accumulator groups (8), and is not affected by the hydraulic oil source (9); the plurality of dynamic load actuators (7) are active, the plurality of constant load actuators (6) are driven, and the thrust of the plurality of constant load actuators (6) is maintained by air springs through the plurality of high-pressure gas cylinder accumulator groups (8), so as to push the third crossbeam (5) to reciprocate on both sides of the balanced position in step S4, and load fatigue load on the cable specimen (1); S6: In the loading fatigue stage in step S5, the control component periodically opens the second electrically controlled valve to compensate the energy loss caused by internal friction of the constant load operating system mainly composed of the plurality of constant load actuators (6) and the plurality of high-pressure gas cylinder accumulator groups (8) through the hydraulic oil source (9); S7: After the standard loading cycle is met, step S2 is repeated, the cable specimen (1) is removed, and after checking that the test equipment is in normal condition, a subsequent fatigue test of the cable specimen (1) is performed.

6. The test method according to claim 5, characterized in that In step S3, when the cable specimen (1) is in a completely unloaded state, a pre-applied air pressure p=p0 is present in a number of the high-pressure gas cylinder accumulator groups (8), the internal high-pressure air volume change ΔV is 0, the load T of a number of the constant load actuators (6) is 0, the load t of a number of the dynamic load actuators (7) is 0, and the length change ΔL of the cable specimen (1) is 0.

7. The test method according to claim 5, characterized in that: In step S4, when the cable specimen (1) reaches a balanced state, the high-pressure air inside the plurality of high-pressure gas cylinder accumulator groups (8) is further compressed by the hydraulic oil, and there is a negative volume change ΔV=-ΔV0, and the air pressure has an increment p=p0+Δp; the load T of the plurality of constant load actuators (6) is T=T0, and the value of T0 is equal to the value of the balanced load; the load t of the plurality of dynamic load actuators (7) is 0; the cable specimen (1) is stretched and lengthened, and the length change ΔL=ΔL0, and at this time, the equilibrium relationship is established: kΔL0=T0=A(p0+Δp) Wherein, k is the tensile stiffness of the cable specimen (1), and A is the total effective area of ​​the hydraulic oil in the plurality of constant load actuators (6).

8. The test method according to claim 5, characterized in that: In step S5, when the cable specimen (1) is further loaded and stretched in a relative equilibrium state, the pistons of the dynamic load actuators (7) retreat, and the load is a tensile force t=δt; the cable specimen (1) is stretched and lengthened compared to the equilibrium state, and the length change ΔL=ΔL0+δL; the pistons of the constant load actuators (6) passively advance, and the negative pressure sucks the hydraulic oil out of the high-pressure gas cylinder accumulator groups (8) respectively, and the hydraulic oil compression of the high-pressure air inside is reduced, and there is a relatively positive volume change, ΔV=-(ΔV0-δV), and the air pressure has a negative increment, p=p0+Δp-δp; the load T of the constant load actuators (6) has a negative increment due to the change in the air pressure of the high-pressure gas cylinder accumulator groups (8), T=T0-δT, and the equilibrium relationship is established at this time: k(ΔL0+δL)=T0-δT+δt=A(p0+Δp-δp)+δt Wherein, k is the tensile stiffness of the cable specimen (1), and A is the total effective area of ​​the hydraulic oil in the plurality of constant load actuators (6).

9. The test method according to claim 8, characterized in that In step S5, when the cable specimen (1) is further loaded and shortened in the relative equilibrium state, the pistons of the dynamic load actuators (7) advance, and the load is a tensile force t=-δt; the cable specimen (1) is shortened compared to the equilibrium state, and the length change ΔL=ΔL0-δL; the pistons of the constant load actuators (6) passively retreat, and the hydraulic oil is pressed from the second hydraulic oil pipelines (11) into the high-pressure gas cylinder accumulator groups (8), and the hydraulic oil squeezed by the high-pressure air inside increases, and there is a relatively negative volume change, ΔV=-(ΔV0+δV), and the air pressure has a positive increment, p=p0+Δp+δp; the load T of the constant load actuators (6) has a positive increment due to the change in the air pressure of the first accumulator groups (8), T=T0+δT, and the equilibrium relationship is established at this time: k(ΔL0-δL)=T0+δT-δt=A(p0+Δp+δp)-δt Wherein, k is the tensile stiffness of the cable specimen (1), and A is the total effective area of ​​the hydraulic oil in the plurality of constant load actuators (6).

10. The test method according to claim 9, characterized in that: In the step S6, the load of the dynamic load actuators (7) in a single fatigue loading cycle is obtained as 2δt based on the balance relationship between the loading stretch and the loading shortening, and: 2δt=2kδL+2Aδp Wherein, k is the tensile stiffness of the cable specimen (1), A is the total effective area of ​​the hydraulic oil in the plurality of constant load actuators (6), 2kδL is the fatigue load amplitude required by the test scheme within a single fatigue loading cycle, and 2Aδp is the compensation for the fluctuation of the constant load operating system within a single fatigue loading cycle.

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