A test device and method for testing creep properties of rope and belt materials

Abstract

The invention discloses a test device for testing the creep performance of rope and belt materials, comprising a rope and belt material clamping and fixing device, a gauge reference row, a gauge reference row fixing fixture, a rope and belt deformation deriving device and a contact sensing test system. The material clamping and fixing device adopts a wavy clamping end with a certain curvature to clamp the two ends of the rope, and uses double-row screws and nuts to pressurize and fix. The gauge reference row and its fixing fixture are used to derive the creep amount of the rope with a fixed gauge length into the contact sensing test system through the deformation deriving device. The invention also discloses a test method for testing the creep performance of rope and belt materials, wherein the rope is kept under a specific tensile load and a specific temperature for a certain time, and a strain-time creep equation of the rope and belt material is established according to deformation measurement data, or a loading load-fracture failure time rope creep life prediction curve is established, thereby forming a creep performance test method for rope and belt materials of different sizes and specifications.

Description

Technical Field

[0001] The invention relates to a test device and a method for testing the creep performance of rope and belt materials, and belongs to the field of material performance measurement and aerospace material engineering application. Background Art

[0002] Flexible rope materials are mainly used in satellite antenna tension ropes, communication satellite antenna main networks, solar wing deployment mechanisms, and extraterrestrial landing parachutes. They play an important role in the structure and function of spacecraft and have broad application prospects in new satellite products. Rope materials are very prone to creep in high-temperature service conditions. After high and low temperature cycles in space, the creep of the material intensifies. The dimensional changes of rope materials under tensile load conditions are related to the technical accuracy and reliability of the product. However, since the creep mode of rope materials is different from that of traditional rigid materials, there is currently no accurate test method to evaluate the creep performance of flexible ropes under load conditions, resulting in a lack of test data and insufficient material performance analysis, which seriously affects the reliability evaluation of the product.

[0003] The standards used to test the creep performance of materials mainly include GB / T 2039-2012 "Metallic Materials Uniaxial Tensile Creep Test Method" and GB / 22077-2008 "Overhead Conductor Creep Test Method". The former is only applicable to the creep test of rigid materials, while the latter is not easy to control the straightness of flexible strip materials, and is not suitable for the fixation of braided rope materials. The GB / T 2039-2012 standard is relatively mature, but it is only applicable to metal materials and other rigid materials processed into smooth shoulder specimens or notched specimens. In GB / 22077-2008, the specimen ends are fixed with materials such as low melting point metals or epoxy resins to avoid wire slippage or interlayer movement during the test, but the straightness and coaxiality of the sample are not easy to maintain, and this method is not suitable for the test of high-temperature creep performance of flexible rope materials. Due to the difference between rope and belt materials and traditional rigid materials, the design idea of ​​rope clamping and fixing devices generally uses adhesives to fix rope materials on reinforcing sheets or wraps them around fixtures. These methods are prone to slippage, resulting in test failure, and are also prone to clamping damage to the rope. Therefore, the existing creep performance test method is not suitable for testing flexible rope materials. It is necessary to design a new test method to accurately test the creep deformation of the material to ensure the realization of the structural design and technical indicators of rope products. Summary of the invention

[0004] The purpose of the present invention is to overcome the above defects and provide a test device and method for the creep performance of rope-like materials, which adopts an optimized rope creep test clamping and fixing device, a gauge reference row, a gauge reference row fixing fixture, a rope deformation derivation test device, a contact sensor test system and a data acquisition system to achieve accurate testing of the creep performance of rope-like materials. Under specific test temperature conditions, a constant tensile stress is applied along the axial direction of the rope sample and maintained for a certain period of time to obtain the strain / creep deformation-time curve of the rope, or the loading load-fracture failure time test data, which is used to evaluate the creep performance of the material or predict the creep life of the rope under a fixed load, effectively making up for the shortcomings of the existing creep performance test methods.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A test device for testing the creep performance of rope and belt materials, comprising a material clamping and fixing device, a gauge reference row, a gauge reference row fixing fixture, a rope and belt deformation deriving device and a contact sensor test system;

[0007] The material clamping and fixing device comprises an upper end and a lower end with the same structure, and both the upper end and the lower end comprise a clamp and a clamp pressing plate. After the clamp and the clamp pressing plate in the upper end and the lower end are fixedly connected, the two ends of the rope are clamped and fixed respectively;

[0008] There are two pairs of gauge reference rows, the upper ends of which are fixedly connected to the two ends of the rope gauge section through two gauge reference row fixing fixtures, and the lower ends of which are connected to the rope deformation derivation device;

[0009] The gauge length reference row fixing fixture comprises a first fixing member and a second fixing member of the same structure, wherein the first fixing member or the second fixing member comprises a clamping claw and a pressure roller, wherein the clamping claw is T-shaped, the tail of the clamping claw is fixedly connected to the gauge length reference row, a groove is arranged in the middle of the clamping claw head, and the pressure roller is embedded in the groove; the clamping claw heads in the first fixing member and the second fixing member are opposite to each other, and after the first fixing member and the second fixing member are fixedly connected, the pressure rollers in the first fixing member and the second fixing member are used to press the rope belt tightly;

[0010] The external mechanical testing machine applies load to the rope through the material clamping and fixing device. The gauge reference row produces displacement changes as the rope elongates due to creep. The displacement change drives the deformation derivation device to generate displacement through the gauge reference row. The contact sensing test system detects the displacement and outputs it to the external data acquisition system.

[0011] Furthermore, the mating surfaces of the chuck and the chuck pressing plate when fixedly connected are both wavy curved surfaces, and the shapes of the mating surfaces of the chuck and the chuck pressing plate are complementary; the curvature radius of the wavy curved surface is R=8-12mm;

[0012] The upper end head and the lower end head also include a double row of end head screws and nuts, which include a first row of end head screws and nuts and a second row of end head screws and nuts, which are respectively arranged on both sides of the upper end head and the lower end head, and each of the first row of end head screws and nuts and the second row of end head screws and nuts includes ≥2 groups of screws and nuts arranged parallel to the axial direction of the rope, and the fixed connection between the chuck and the chuck pressure plate is achieved by the double row of end head screws and nuts.

[0013] Furthermore, the gauge reference row fixing fixture also includes a double-row screw nut and a single-row screw nut. The double-row screw nut is designed on the head of the jaw for fixing and connecting the first fixing member and the second fixing member. The single-row screw nut is used to fix the tail of the jaw and the upper end of the gauge reference row.

[0014] The double-row screws and nuts of the clamping jaws include a first row of fixing screws and nuts and a second row of fixing screws and nuts, wherein the first row of fixing screws and nuts and the second row of fixing screws and nuts are respectively arranged on the head of the clamping jaws and located on both sides of the groove, and each of the first row of fixing screws and nuts and the second row of fixing screws and nuts includes ≥2 groups of screws and nuts arranged parallel to the axial direction of the rope;

[0015] The single-row screw and nut of the clamping claw includes ≥2 groups of screws and nuts which are arranged parallel to the axial direction of the rope.

[0016] Furthermore, the groove of the claw head passes through the centroid of the end surface of the claw head and the direction of the groove is perpendicular to the axial direction of the rope.

[0017] Furthermore, the rope deformation derivation device includes two derivation plates, a double-row connecting rod and a double-row spring; the two derivation plates are perpendicular to the rope axis and arranged along the rope axis, and the lower ends of the two pairs of gauge reference rows are respectively connected to the two derivation plates; the double-row connecting rod includes a first row of connecting rods and a second row of connecting rods respectively arranged on the two derivation plates, and the first row of connecting rods and the second row of connecting rods each include two connecting rods arranged perpendicular to the rope axis; the double-row spring includes a first row of springs and a second row of springs, the first row of springs is connected between the two connecting rods in the first row of connecting rods, and the second row of springs is connected between the two connecting rods in the second row of connecting rods, the extension and contraction direction of the double-row springs is parallel to the arrangement direction of the two connecting rods, and the double-row connecting rods and the double-row springs are used for connecting and fixing the gauge reference row and the deformation derivation device.

[0018] Furthermore, the contact sensing test system includes two contact sensing detectors disposed between two export plates, for detecting the displacement of the two export plates in the rope deformation export device.

[0019] Furthermore, it also includes a roller, and the lower end of the gauge reference row is displaced by sliding along a guide rail parallel to the axial direction of the rope through the roller.

[0020] A test method for testing the creep performance of rope and belt materials is implemented by using the above-mentioned test device for testing the creep performance of rope and belt materials, and comprises the following steps:

[0021] S1 connects the upper end and the lower end of the material clamping and fixing device to the mechanical testing machine respectively, and clamps and fixes the two ends of the rope respectively through the fixed connection of the clamp and the clamp pressure plate in the upper end and the lower end;

[0022] S2 raises the temperature of the heating box to the test temperature, and at the same time preloads the rope belt through the mechanical testing machine, and keeps the rope belt warm until the deformation of the rope belt material caused by thermal expansion is fully released;

[0023] S3: The upper ends of the two pairs of gauge length reference rows are fixedly connected to the two ends of the gauge length section of the rope through the gauge length reference row fixing fixtures, and the lower ends of the two pairs of gauge length reference rows are connected to the rope deformation deriving device; the rope deformation deriving device is connected to the contact sensor test system;

[0024] S4: Under the test temperature, the rope is gradually loaded to the test load by a mechanical testing machine, and the displacement of the deformation deriving device at different times is obtained by a contact sensor test system under the test load, so as to obtain the creep strain of the rope at different times;

[0025] S5 draws a creep strain-time curve of the rope belt according to the strain of the rope belt obtained in step S4;

[0026] The material clamping and fixing device, the gauge length reference row and the gauge length reference row fixing fixture are placed in the heating box, and the rope deformation amount deriving device and the contact sensing test system are placed outside the heating box.

[0027] Furthermore, in the above test method for testing the creep performance of rope and belt materials, the temperature change of the rope and belt gauge section during the test is less than ±2°C;

[0028] In the step S2, the rope is preloaded with an initial load not greater than 2% of the rated breaking force of the rope by a mechanical testing machine;

[0029] In step S4, during the gradual loading of the rope, each loading time is 5 min ± 10 s, each loading increment does not exceed 20% of the test load, and the test duration is not less than 1000 h;

[0030] In step S4, the displacement of the deformation deriving device at different times is obtained by the contact sensor test system, and the increment ΔL of the reference length of the rope is obtained according to the displacement. rt , the creep elongation (i.e. creep strain) of the rope at different time points is obtained according to the following formula:

[0031]

[0032] Where: L ro is the original reference length, ΔL rt is the increment of the original reference length, A f is the creep elongation at time t.

[0033] Furthermore, the above-mentioned test method for testing the creep performance of rope materials also includes using the measured values ​​within the creep temperature holding time as the creep data of the rope under the test temperature and test tensile load, establishing a long-term creep equation, obtaining the equation coefficients by linear regression and estimating the creep amount of the rope material with a calculation period of years; or obtaining the loading load and fracture failure time data, predicting the creep life of a given load through curve fitting, or calculating the load range that can be carried to achieve the required creep life.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) In a test device and method for testing creep properties of rope-like materials of the present invention, the interior of the rope-like material clamping and fixing device is designed to be a wavy structure, which can increase the contact length (area) between the rope and the clamp, so that under a fixed load condition, the load per unit length (area) of the clamping part is reduced, which is conducive to more evenly distributing the load and increasing the stability of clamping; compared with a flat clamp, the wavy clamp is subjected to the force components of the clamping end in the horizontal direction and the vertical direction at the same time, which is more conducive to the fixation of the end, and realizes the stable clamping of the rope material end;

[0036] (2) In the test device and method for testing the creep performance of rope materials of the present invention, the material clamping and fixing device adopts double-row screws and nuts for pressure fixing, which further increases the friction between the rope and the wavy clamp, and the pressing force can be adjusted according to the size of different ropes. By adjusting the tightening degree of the end screws and nuts, the rope materials of different thickness specifications can be clamped, so that the device has strong flexibility and can be extended to the testing of other flexible materials;

[0037] (3) The test device for testing the creep performance of rope-like materials of the present invention adopts a method of cooperating T-shaped claws, grooves and pressure rollers to clamp the two ends of the rope gauge section. The clamping is stable and will not damage the rope. At the same time, the straightness and coaxiality of the clamped sample are improved. As a key component of the test device, it realizes the accurate test of the creep deformation of flexible rope-like materials for the first time.

[0038] (4) The test device of the present invention has strong versatility. The deformation of the flexible rope material is derived by using the deformation deriving device and the gauge length reference row. The test device and method are not only applicable to room temperature but also can solve the problem of high temperature creep performance test. It can also be extended to the creep performance test of rope materials under high and low temperature change conditions, meeting the needs of spacecraft rope materials for space temperature environment adaptability assessment and verification;

[0039] (5) In a test method for testing the creep performance of rope materials of the present invention, the rope material is preloaded under creep temperature conditions before the test, so that the deformation of the rope material caused by thermal expansion is fully released, thereby reducing the measurement uncertainty caused by the elongation caused by the thermal expansion of the rope, thereby improving the accuracy of the rope creep performance test;

[0040] (6) The creep strain-time curve obtained by the creep performance test method of rope and belt materials of the present invention is closer to the actual deformation process of the material when loaded, and a loading load-fracture failure time rope creep life prediction curve is established, which effectively makes up for the shortcomings of the existing creep performance test method and realizes the evaluation of the service reliability of rope and belt materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the clamping method of the creep performance test device for rope and belt materials of the present invention;

[0042] Figure 2 It is a schematic diagram of the rope material clamping and fixing device, the gauge length reference row, the gauge length reference row fixing fixture and the connection method thereof of the present invention;

[0043] Figure 3 It is a schematic diagram of the gauge length reference row, deformation derivation device, contact sensor test system and their connection method of the present invention;

[0044] Figure 4 Schematic diagram of the structure of the clamping and fixing device for rope and belt materials of the present invention; wherein, Figure (a) is a schematic diagram of the clamping plate, Figure (b) is a schematic diagram of the clamp, and Figure (c) is a schematic diagram of the combination of the clamping plate and the clamp;

[0045] Figure 5 The figure is a schematic diagram of the composition structure of the gauge reference row fixing fixture of the present invention; wherein, figure (a) is a schematic diagram of the structure of the clamping claw and the pressure roller, and figure (b) is a schematic diagram of the installation position of the clamping claw and the pressure roller;

[0046] Figure 6 The creep strain-time curve is measured by the creep performance testing method of rope and belt materials in the present invention;

[0047] Figure 7 The present invention uses the creep performance testing method of rope and belt materials to obtain a loading load-fracture failure time life prediction curve. DETAILED DESCRIPTION

[0048] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0049] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0050] The present invention discloses a test device and method for the creep performance of rope-like materials, comprising a rope-like material clamping and fixing device 1, a gauge reference row 2, a gauge reference row fixing fixture 3, a rope deformation derivation test device 4 and a contact sensing test system 5. The rope-like material clamping and fixing device is used to clamp the two ends of the rope, and a double row of screws and nuts are used to pressurize and fix. The gauge reference row and its fixing fixture are used to derive the creep deformation of the rope with a fixed gauge length into the contact sensing test system through the deformation derivation device, and the rope is kept at a specific tensile load and a specific temperature for a certain period of time. According to the deformation measurement data, a strain-time creep equation of the rope material is established, or a loading load-fracture failure time rope creep life prediction curve is established, thereby forming a creep performance test method suitable for rope-like materials of different sizes and specifications.

[0051] The rope-like material clamping and fixing device 1 is composed of two symmetrical upper and lower ends, and the rope material samples are fixed at the two ends respectively; each end includes a pair of chucks 6 and a chuck pressure plate 7, and the inner side surfaces of the chucks 6 and the chuck pressure plate 7 (i.e., the mating surfaces when fixedly connected) are designed to be wavy surfaces with a certain curvature (R=8~12mm). The outer sides of the chucks 6 and the chuck pressure plate 7 use double-row screws and nuts 8 at the end to pressurize and fix the rope material clamped by the end as a whole. On the one hand, the clamping force on the rope sample can be adjusted, and on the other hand, the friction between the sample and the wavy chuck pressure plate can be increased. By adjusting the tightening degree of the double-row screws and nuts at the end, the rope materials of different thicknesses can be clamped, so that the rope will not slide at the end even under a large constant load. Figure 1 As shown, the length of the rope sample to be tested should be greater than 100d+2a, where d is the rope width and a is the distance between the end of the clamping and fixing device 1 and the near end of the gauge section L0.

[0052] The gauge reference row 2 is used to calibrate the deformation of the rope material sample. The gauge reference row 2 consists of two pairs. The two pairs of gauge reference rows are of left-right symmetrical structure. The upper ends are fixedly connected to the two ends of the rope gauge section L0 through two gauge reference row fixing fixtures 3. The gauge reference row fixing fixture 3 adopts a T-shaped clamping jaw 9 and a pressure roller 10 for crimping and fixing. Two pressure rollers 10 with a diameter of 3 mm are pressed on both sides of the rope. Among them, a double-row clamping jaw screw nut 11 is set at the head of the clamping jaw to pressurize and fix the pressure roller 10, and a single-row clamping jaw screw nut 12 is set at the tail to connect with the gauge reference row 2. Figure 5 shown.

[0053] Specifically, Figure 1 It is a schematic diagram of the clamping method of the creep performance test device for rope-like materials, showing the rope-like material clamping and fixing device 1, the gauge reference row 2, the gauge reference row fixing fixture 3 and the fixing position of the rope, the rope gauge section L0, the rope width d, and the distance a between the middle end of the clamping and fixing device and one end of the gauge section L0, wherein the length of the gauge section L0 is at least 100d.

[0054] Figure 2 It is a schematic diagram of a rope-like material clamping and fixing device 1, a gauge reference row 2, a gauge reference row fixing fixture 3 and their connection method. The gauge reference row 2 is used to calibrate the deformation of the rope material sample. The gauge reference row 2 is divided into two pairs, and the two pairs of gauge reference rows are respectively symmetrical structures. The upper ends of the two pairs of gauge reference rows are fixedly connected to the two ends of the rope gauge section L0 through two gauge reference row fixing fixtures 3, and the distance difference between the upper ends of the two pairs of gauge reference rows is the gauge section L0.

[0055] Figure 3 It is a schematic diagram of the gauge reference row 2, the deformation derivation device 4, the contact sensor test system 5 and their connection parts. The lower end of the gauge reference row 2 is connected to the deformation derivation device 4, and the lower ends of the two pairs of gauge reference rows are tightly connected to the two derivation plates 13 in the deformation derivation device 4 respectively. The precise positioning of the four positions is achieved by the double-row connecting rods 14 and the double-row springs 15. The gauge reference row 2 produces a displacement change with the creep elongation of the rope, and the deformation derivation device 4 is driven by the roller 17 to move along the axial direction of the rope, and the deformation derivation device 4 derives the displacement of the gauge reference row 2 to the outside of the heating box.

[0056] Figure 4 The figure is a schematic diagram of the composition structure of the rope-like material clamping and fixing device, where the material clamping and fixing device 1 consists of two symmetrical upper and lower ends, each of which consists of a clamp 6 and a clamp pressure plate 7, which respectively fix the two ends of the rope material sample; the interior of the clamp 6 and the clamp pressure plate 7 is designed to have a wavy curved surface structure with a certain curvature, and a double-row screw nut 8 is used on the outside to pressurize and fix the end as a whole.

[0057] Figure 5 The schematic diagram of the structure of the gauge reference row fixing fixture is shown in FIG. The gauge reference row fixing fixture 3 includes two fixing parts with the same structure, namely the first fixing part and the second fixing part. Each fixing part is mainly composed of a clamping claw 9 and a pressure roller 10. The clamping claw 9 is T-shaped. A pressure roller 10 with a diameter of 3 mm is fixed at the center of the head of the clamping claw 9. When the pressure is applied, the pressure roller 10 is embedded in the groove at the center of the head of the clamping claw 9.

[0058] The lower end of the gauge reference row 2 is tightly connected to the deformation derivation device 4 through a double row of connecting rods 14 and a double row of springs 15. Through the precise positioning of the four positions of the first row of connecting rods and the second row of connecting rods, the first row of springs and the second row of springs, the gauge reference row 2 is derived from the deformation derivation device 4 to the outside of the heating box as the creep displacement of the rope changes.

[0059] The deformation derived from the gauge reference row 2 connected to the upper end of the rope gauge section L0 is transmitted to the upper end of the contact sensor detector 16 through the deformation deriving device 4, and the deformation derived from the gauge reference row 2 connected to the lower end of the rope sample gauge section L0 is transmitted to the lower end of the contact sensor detector 16 through the deformation deriving device 4. The contact sensor test system 5 is used in conjunction with the data acquisition system to realize the testing and acquisition of rope deformation.

[0060] In order to accurately derive the deformation of the rope material, the rope material is preloaded before the test and heated and kept warm for 10 minutes under creep temperature conditions to fully release the deformation of the rope material caused by thermal expansion. The creep deformation is then tested to reduce the interference factors caused by the thermal expansion of the rope during the test, thereby reducing the measurement uncertainty caused by the elongation caused by the thermal expansion of the rope.

[0061] Furthermore, the initial load before the test is allowed to reach 2% of the rated breaking force of the rope. The loading time during the test is 5min±10s, and the load is evenly applied to the test load without overloading.

[0062] Furthermore, loading should be performed in steps, with each increment not exceeding 20% ​​of the test load. When loading is performed in steps, it should be ensured that the area covered by the stress-time diagram of the loading curve is equal to the area covered by the straight line from the preload or zero load to the final test load.

[0063] Furthermore, when measuring the strain of the rope material at different times, the original reference length L ro and the reference length increment ΔL rt Carry out precise testing and calculate the creep elongation A at different time points (time t) f The method for determining is:

[0064]

[0065] Where: L ro is the original reference length, ΔL rt is the increment of the original reference length, A f is the creep elongation at time t.

[0066] The present invention provides a test device and method for testing creep performance of rope and belt materials, comprising the following steps:

[0067] Step 1: Connect the upper and lower ends of the material clamping and fixing device 1 in the test device for testing the creep performance of the rope to the mechanical testing machine through the upper and lower adapters respectively, pass the rope through the clamp 6 and the clamp pressure plate 7, connect the clamp 6 and the clamp pressure plate 7 with the double-row screw nut 8 at the end, and pressurize the end by tightening the nut until the rope is firmly fixed;

[0068] Step 2: Turn on the mechanical testing machine for preloading, and allow the initial load to reach 2% of the rated breaking force of the rope. Connect the upper end of the gauge reference row 2 to the rope material, and use the clamping claw 9 and the pressure roller 10 to crimp and fix. Align the first fixture in the gauge reference row fixing fixture with the head of the second fixture, and tighten the double-row screw nut 11 of the clamping claw at the head of the two fixtures to press the two rollers embedded in the groove on both sides of the rope. The tail of the clamping claw 9 is connected to the gauge reference row 2 through the clamping claw single-row screw nut 12;

[0069] Step 3: Connect the lower end of the gauge reference row 2 to the deformation derivation device 4 through the double-row connecting rod 14 and the double-row spring 15. The gauge reference row 2 produces displacement changes with the creep elongation of the rope belt, and the lower end of the gauge reference row 2 slides along the guide rail parallel to the rope belt axis through the roller 17 to move, driving the deformation derivation device 4 to derive the displacement of the gauge reference row 2 to the outside of the heating box;

[0070] Step 4: The two ends of the two export plates 13 in the rope deformation export device 4 are respectively in close contact with the two contact sensor detectors 16 perpendicular to the export plates in the contact sensor test system 5. The deformation derived from the gauge reference row 2 connected to the upper end of the rope gauge section L0 is transmitted to the upper end of the contact sensor detector 16 through the deformation export device 4, and the deformation derived from the gauge reference row 2 connected to the lower end of the rope sample gauge section L0 is transmitted to the lower end of the contact sensor detector 16 through the deformation export device 4. The contact sensor detector 16 detects the micro deformation of the rope and transmits the signal to the data acquisition system.

[0071] Step 5: In order to monitor and control the internal temperature of the furnace in real time, three thermocouples are pasted at both ends and in the middle of the gauge section. Two thermocouples are pasted on the two gauge reference row fixing fixtures 3 that clamp the rope, and one thermocouple is pasted on the gauge reference row 2. The temperature is controlled so that the temperature change of the rope during the creep test is less than ±2°C;

[0072] Step 6: Cover the heating box, set the temperature and gradually load the test load through the mechanical testing machine. Do not overload. The loading time should be 5min±10s. During the gradual loading, the increment each time should not exceed 20% of the test load. The test duration should not be less than 1000h to fully and accurately predict the long-term creep of the rope;

[0073] Step seven, measure the strain of the rope material at different times, calculate the creep strain elongation of the rope at different time points according to formula (1), and draw a creep strain-time curve.

[0074] The measured values ​​within the creep temperature holding time are used as the rope creep data under specific temperature and specific tensile load, and the creep equation is established. The equation coefficients are obtained by linear regression and the rope creep amount with year as the calculation period is estimated.

[0075] Furthermore, the test data of loading load and fracture failure time are used to perform curve fitting on the test data, and the creep life of the rope with a given load is extrapolated and predicted, or the load range that can be carried is calculated to achieve the required creep life.

[0076] Example 1

[0077] The following is a detailed description of the implementation method of the present invention by taking the creep performance test method of polyimide rope material as an example.

[0078] (1) Connect the upper and lower ends of the material clamping and fixing device 1 in the test device for creep performance of the test rope to the mechanical testing machine through the upper and lower adapters respectively, pass the rope through the clamp 6 and the clamp pressure plate 7, connect the clamp 6 and the clamp pressure plate 7 with the double-row end screw nut 8, pressurize the end by tightening the nut until the rope is firmly fixed, and fix the upper and lower ends of the rope sample in the same way;

[0079] (2) Turn on the mechanical testing machine and preload the rope, allowing the initial load to reach 2% of the rated breaking force of the rope. Connect the upper end of the gauge reference row 2 to the rope through the gauge reference row fixing fixture 3. The gauge reference row fixing fixture 3 adopts the method of crimping and fixing the clamping claw 9 and the pressure roller 10. The first fixing member in the gauge reference row fixing fixture is opposite to the clamping claw head in the second fixing member. By tightening the clamping claw double-row screw nut 11, the two pressure rollers embedded in the groove are pressed on both sides of the rope respectively. The tail of the clamping claw 9 is connected to the gauge reference row 2 through the clamping claw single-row screw nut 12;

[0080] (3) The lower end of the gauge reference row 2 is connected to the deformation derivation device 4 through a double row of connecting rods 14 and double row of springs 15, and the stability is increased through precise positioning of four positions. The gauge reference row 2 produces displacement changes with the creep elongation of the rope, and the roller 17 slides along the guide rail parallel to the rope axis to drive the deformation derivation device 4 to move, and the displacement of the gauge reference row 2 is derived to the outside of the heating box by the deformation derivation device 4;

[0081] (4) The two ends of the two export plates 13 in the deformation export device 4 are respectively supported by two contact sensor detectors 16 in the contact sensor test system 5 which are perpendicular to the export plates, wherein the deformation derived from the gauge reference row 2 connected to the upper end of the rope gauge section L0 is transmitted to the upper ejector pin of the contact sensor detector 16 through the deformation export device 4, and the deformation derived from the gauge reference row 2 connected to the lower end of the rope sample gauge section L0 is transmitted to the lower end of the contact sensor detector 16 through the deformation export device 4. The contact sensor detector 16 detects the micro deformation of the rope and transmits the signal to the data acquisition system;

[0082] (5) Paste the thermocouples at both ends and in the middle of the gauge section. Two thermocouples are pasted on the two gauge reference row fixing fixtures 3 that clamp the rope, and one thermocouple is pasted on the gauge reference row 2. Control the temperature so that the rope temperature change is less than ±2°C during the creep test;

[0083] (6) Cover the heating box, set the temperature and then gradually load the rope using a mechanical testing machine. The loading time should be 5 min ± 10 s. Each increment should not exceed 20% of the test load, and the test load should not exceed 60% of the rope breaking load. The test duration should not be less than 1000 h to fully and accurately predict the long-term creep of the rope.

[0084] (7) The strain of the rope material is measured at different times, and the creep strain elongation of the rope at different times is calculated according to the method of formula (1). The measured value within the creep temperature holding time is used as the creep data of the rope under a specific temperature and a specific tensile load, and a creep strain-time curve is drawn;

[0085] (8) The creep amount of the rope under long-term service life can be realized by processing the 1000h creep test data. The creep equation is derived by using the linear regression line from the measured values ​​of 1h to 1000h, and the equation coefficients are obtained to calculate the creep amount of the rope in 5 to 10 years. The creep test of the polyimide rope was carried out at a constant temperature of 100℃ and a constant load of 5kN, and the result was Figure 6 The creep strain-time curve is shown in Figure 2. Using the above 100℃, 5kN load rope creep data, the creep equation is established:

[0086] ε=A×lgt, (2)

[0087] Where: ε is the creep strain of the rope after a certain period of time, A is the linear regression coefficient of the equation, and t is the total creep time.

[0088] The linear regression coefficient A=0.0558299, calculated based on 5 years and 43800 hours, the total creep strain of the rope is 0.26%.

[0089] Example 2

[0090] The following is a detailed description of the implementation method of the present invention by taking the high temperature creep life test and prediction method of Vectran rope (56×4tex) material at 125°C as an example.

[0091] (1) Connect the upper and lower ends of the material clamping and fixing device 3 in the test device for creep performance of the test rope to the mechanical testing machine through the upper and lower adapters respectively, pass the rope through the chuck 6 and the chuck pressure plate 7, connect the chuck and the chuck pressure plate with double-row end screw nuts 8, pressurize the ends by tightening the nuts until the rope is firmly fixed, and fix the upper and lower ends of the rope sample in the same way;

[0092] (2) Turn on the mechanical testing machine and perform the ultimate tensile test on each axis of the rope for no less than 5 times to obtain the average breaking force (breaking strength). The load of the Vectran rope creep test is set based on the average breaking force, expressed as a percentage of the breaking force.

[0093] (3) Preload the Vectran rope, and allow the initial load to reach 2% of the rated breaking force of the rope. Connect the upper end of the gauge reference row 2 to the rope through the gauge reference row fixing fixture 3. The gauge reference row fixing fixture 3 uses a clamping claw 9 and a pressure roller 10 to fix the first fixture in the gauge reference row fixing fixture and the clamping claw head in the second fixture opposite to each other. Tighten the double-row screw nut 11 of the clamping claw to press the two pressure rollers embedded in the groove on both sides of the rope. The tail of the clamping claw 9 is connected to the gauge reference row 2 through the single-row screw nut 12 of the clamping claw;

[0094] (4) The lower end of the gauge reference row 2 is connected to the deformation derivation device 4 through a double row of connecting rods 14 and double row of springs 15, and the stability is increased through precise positioning of four positions. The lower end of the gauge reference row 2 is displaced by sliding along a guide rail parallel to the axial direction of the rope through a roller 17, and the displacement of the gauge reference row 2 is derived to the outside of the heating box by the deformation derivation device 4;

[0095] (5) The two ends of the two export plates 13 in the deformation export device 4 are respectively in close contact with two contact sensor detectors 16 in the contact sensor test system 5 which are perpendicular to the export plates 13, wherein the deformation derived from the gauge reference row 2 connected to the upper end of the rope gauge section L0 is transmitted to the upper end of the contact sensor detector 16 through the deformation export device 4, and the deformation derived from the gauge reference row 2 connected to the lower end of the rope sample gauge section L0 is transmitted to the lower end of the contact sensor detector 16 through the deformation export device 4, and the contact sensor detector 16 detects the micro deformation of the rope and transmits the signal to the data acquisition system;

[0096] (6) Paste the thermocouples at both ends and in the middle of the gauge section. Two thermocouples are pasted on the two gauge reference row fixing fixtures 3 that clamp the rope, and one thermocouple is pasted on the gauge reference row 2. Control the temperature so that the rope temperature change during the creep test is less than ±2°C;

[0097] (7) Cover the heating box, set the temperature, and then use a mechanical testing machine to load different percentages of average breaking force (55% to 95% breaking force), and record the breaking failure time (test duration) at different loads;

[0098] (8) Curve fitting is performed on each set of data, and the curve is extrapolated to predict the creep life of a given load or to calculate the load range that can be carried to achieve the required creep life. The fitted rope life curve is as follows: Figure 7 shown.

[0099] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0100] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A test device for testing the creep performance of rope and belt materials, characterized in that: It comprises a material clamping and fixing device (1), a gauge length reference row (2), a gauge length reference row fixing fixture (3), a rope deformation amount derivation device (4) and a contact sensing test system (5); The material clamping and fixing device (1) comprises an upper end and a lower end with the same structure, and the upper end and the lower end both comprise a clamp (6) and a clamp pressure plate (7). After the clamp (6) and the clamp pressure plate (7) in the upper end and the lower end are fixedly connected, the two ends of the rope are clamped and fixed respectively. There are two pairs of gauge reference rows (2), the upper ends of the two pairs of gauge reference rows are fixedly connected to the two ends of the rope gauge section through two gauge reference row fixing clamps (3), and the lower ends of the two pairs of gauge reference rows are connected to the rope deformation derivation device (4); The gauge length reference row fixing fixture (3) comprises a first fixing member and a second fixing member of the same structure, wherein the first fixing member or the second fixing member comprises a clamping claw (9) and a pressure roller (10), wherein the clamping claw (9) is T-shaped, the tail of the clamping claw (9) is fixedly connected to the gauge length reference row (2), a groove is provided in the middle of the head of the clamping claw (9), and the pressure roller (10) is embedded in the groove; the heads of the clamping claws (9) in the first fixing member and the second fixing member are opposite to each other, and after the first fixing member and the second fixing member are fixedly connected, the pressure rollers (10) in the first fixing member and the second fixing member are used to press the rope belt; The external mechanical testing machine applies a load to the rope belt through the material clamping and fixing device (1), and the gauge length reference row (2) produces a displacement change as the rope belt creeps and elongates. The displacement change drives the deformation amount deriving device (4) to generate displacement through the gauge length reference row (2), and the contact sensor test system (5) detects the displacement and outputs it to the external data acquisition system; The rope deformation derivation device (4) comprises two derivation plates (13), a double row of connecting rods (14) and a double row of springs (15); The two export plates (13) are perpendicular to the axial direction of the rope and arranged along the axial direction of the rope, and the lower ends of the two pairs of gauge length reference rows are respectively connected to the two export plates (13); The double-row connecting rod (14) comprises a first row of connecting rods and a second row of connecting rods respectively arranged on two export plates (13), and each of the first row of connecting rods and the second row of connecting rods comprises two connecting rods arranged axially with vertical ropes; the double-row springs (15) comprise a first row of springs and a second row of springs, and the first row of springs is connected between two connecting rods in the first row of connecting rods, and the second row of springs is connected between two connecting rods in the second row of connecting rods. The telescopic direction of the double-row springs (15) is parallel to the arrangement direction of the two connecting rods. The double-row connecting rods (14) and the double-row springs (15) are used for connecting and fixing the gauge length reference row (2) and the deformation amount export device (4).

2. A test device for testing creep properties of rope and belt materials according to claim 1, characterized in that: The mating surfaces of the chuck (6) and the chuck pressure plate (7) when they are fixedly connected are both wavy curved surfaces, and the shapes of the mating surface of the chuck (6) and the mating surface of the chuck pressure plate (7) are complementary; the curvature radius R of the wavy curved surface is 8 to 12 mm; The upper end head and the lower end head also include a double row of end head screw nuts (8), the double row of end head screw nuts (8) include a first row of end head screw nuts and a second row of end head screw nuts, the first row of end head screw nuts and the second row of end head screw nuts are respectively arranged on both sides of the upper end head and the lower end head, the first row of end head screw nuts and the second row of end head screw nuts each include ≥2 groups of screw nuts that are arranged parallel to the axial direction of the rope belt, and the double row of end head screw nuts (8) are used to achieve fixed connection between the chuck (6) and the chuck pressure plate (7).

3. A test device for testing creep properties of rope and belt materials according to claim 1, characterized in that: The gauge length reference row fixing fixture (3) further comprises a double-row screw nut (11) of a clamping jaw and a single-row screw nut (12), wherein the double-row screw nut (11) of the clamping jaw head is used for fixing and connecting the first fixing member and the second fixing member, and the single-row screw nut (12) of the clamping jaw is used for fixing and connecting the tail of the clamping jaw (9) and the upper end of the gauge length reference row (2); The double-row screw nuts (11) of the clamping jaws include a first row of screw nuts for fixing parts and a second row of screw nuts for fixing parts. The first row of screw nuts for fixing parts and the second row of screw nuts for fixing parts are respectively arranged on the head of the clamping jaws (9) and located on both sides of the groove. The first row of screw nuts for fixing parts and the second row of screw nuts for fixing parts each include ≥2 groups of screw nuts arranged parallel to the axial direction of the rope. The clamping claw single-row screw and nut (12) comprises ≥2 groups of screws and nuts which are arranged parallel to the axial direction of the rope.

4. A test device for testing creep properties of rope and belt materials according to claim 1 or 3, characterized in that: The groove on the head of the claw (9) passes through the centroid of the end surface of the head of the claw (9), and the direction of the groove is perpendicular to the axial direction of the rope.

5. A test device for testing creep properties of rope and belt materials according to claim 1, characterized in that: The contact sensing test system (5) comprises two contact sensing detectors (16) arranged between two export plates (13) and used for detecting the displacement of the two export plates (13) in the rope deformation export device (4).

6. A test device for testing creep properties of rope and belt materials according to claim 1, characterized in that: It also includes a roller (17), through which the lower end of the gauge length reference row (2) slides along a guide rail parallel to the axial direction of the rope belt to move.

7. A test method for testing the creep performance of rope and belt materials, characterized in that: The test device for testing the creep performance of rope and belt materials according to any one of claims 1 to 6 is used to implement the test, comprising the following steps: S1 connects the upper end and the lower end of the material clamping and fixing device (1) to the mechanical testing machine respectively, and clamps and fixes the two ends of the rope respectively through the fixed connection of the clamp (6) and the clamp pressure plate (7) in the upper end and the lower end; S2 raises the temperature of the heating box to the test temperature, and at the same time preloads the rope belt through the mechanical testing machine, and keeps the rope belt warm until the deformation of the rope belt material caused by thermal expansion is fully released; S3: The upper ends of the two pairs of gauge length reference rows are fixedly connected to the two ends of the gauge length section of the rope belt through the gauge length reference row fixing fixtures (3), and the lower ends of the two pairs of gauge length reference rows are connected to the rope belt deformation derivation device (4); the rope belt deformation derivation device (4) is connected to the contact sensor test system (5); S4, at the test temperature, the rope belt is gradually loaded to the test load by a mechanical testing machine, and the displacement of the deformation deriving device (4) at different times is obtained by a contact sensor test system (5) under the test load, thereby obtaining the creep strain of the rope belt at different times; S5 draws a creep strain-time curve of the rope belt according to the strain of the rope belt obtained in step S4; The material clamping and fixing device (1), the gauge length reference row (2) and the gauge length reference row fixing fixture (3) are placed in a heating box, and the rope deformation amount derivation device (4) and the contact sensor test system (5) are placed outside the heating box.

8. A test method for testing creep properties of rope and belt materials according to claim 7, characterized in that: During the test, the temperature change of the rope gauge section is less than ±2℃; In the step S2, the rope is preloaded with an initial load not greater than 2% of the rated breaking force of the rope by a mechanical testing machine; In step S4, during the gradual loading of the rope, each loading time is 5 min ± 10 s, each loading increment does not exceed 20% of the test load, and the test duration is not less than 1000 h; In the step S4, the displacement of the deformation deriving device (4) at different times is obtained by the contact sensing test system (5), and the increment ΔL of the reference length of the rope is obtained according to the displacement. rt , the creep elongation of the rope at different time points is obtained according to the following formula: Where: L ro is the original reference length, ΔL rt is the increment of the original reference length, A f is the creep elongation at time t.

9. A test method for testing creep properties of rope and belt materials according to claim 7, characterized in that: It also includes using the measured values ​​within the creep temperature holding time as the creep data of the rope under the test temperature and test tensile load, establishing a long-term creep equation, obtaining the equation coefficients by linear regression and estimating the creep amount of the rope material with a calculation period of years; or obtaining the loading load and fracture failure time data, predicting the creep life of a given load through curve fitting, or calculating the load range that can be carried in order to achieve the required creep life.

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