Electric pole torsion resistance comprehensive test device and evaluation system and method

Abstract

The invention belongs to the field of electric pole detection, and particularly relates to an electric pole torsion resistance comprehensive test device and evaluation system and method.The system comprises a data collecting and processing unit and a comprehensive evaluation unit which are in communication connection with a measuring assembly of the test device and used for synchronously receiving and processing multi-source data from different sensors; the comprehensive evaluation unit is in communication connection with the data acquisition and processing unit, and a torsion resistance attenuation prediction model is arranged in the comprehensive evaluation unit; the torsion resistance attenuation prediction model is configured to calibrate model parameters based on individual feature data extracted in a current test, and calculate and output a torsion resistance attenuation quantitative prediction result of the electric pole.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electric pole detection, more specifically, relates to an electric pole torsional performance comprehensive test device and evaluation system and method. BACKGROUND

[0002] The electric pole is the core support structure of the power transmission line, and needs to bear various loads in actual operation, in which the torsional load is one of the key working conditions. For example, in the process of tightening the line during the stringing construction, the tension applied through the cross arm will generate a significant torque on the electric pole; in the severe weather such as typhoon and gale, the wind sway or different period ice shedding of the conductor will also exert an alternating or impact torque on the electric pole. When the torque exceeds the torsional bearing capacity of the electric pole itself, the electric pole will be cracked, damaged or even collapsed, which seriously threatens the safety of the power grid.

[0003] At present, the detection of the mechanical performance of the electric pole is mostly focused on the compression resistance, bending resistance and uplift resistance, and the systematic test means for the torsional performance is relatively scarce. The existing test devices have single functionality. Most of the devices can only perform simple static tensile and torsional strength tests, and the loading capacity and structural form are difficult to adapt to the full-size electric pole, and it is impossible to simulate the long-term dynamic load working conditions such as wind-induced vibration.

[0004] Secondly, the evaluation dimension is incomplete, and the traditional method can only obtain the terminal indicators such as the limit torque, and cannot reveal the key mechanical behavior information such as the distribution rule of the torsional deformation along the pole body, the crack initiation and propagation process, etc.

[0005] Therefore, in view of the above problems, the existing structure and defects are researched and improved, and an electric pole torsional performance comprehensive test device and evaluation system and method are provided, so as to achieve a more practical value purpose. SUMMARY

[0006] Based on the problems mentioned in the above background art, the present application provides an electric pole torsional performance comprehensive test device and evaluation system and method.

[0007] In one aspect, the technical scheme adopted by the present application is as follows: an electric pole torsional performance comprehensive test device, comprising a base, a test table is arranged on the base, a clamping and supporting assembly is installed on the test table, the clamping and supporting assembly is used for fixing and supporting the electric pole to be tested, and comprises at least two supporting clamps for supporting the pole body of the electric pole and a torsional clamp provided at the top end of the electric pole and having a torsional arm; the supporting clamp comprises a lifting hydraulic rolling support, the lifting hydraulic rolling support comprises a V-shaped groove, a hydraulic mechanism for driving the V-shaped groove to lift, and a supporting roller rotatably arranged in the V-shaped groove; a torque loading assembly is used for applying a torque to the electric pole through the torsional clamp; and a measuring assembly is used for collecting torque, displacement, angle of rotation and image data during the test.

[0008] Further, the torque loading assembly comprises a traction member connecting the ends of the torsion arms, an electric tension tool for applying tension to the traction member, and a fixing pile for fixing the electric tension tool.

[0009] Further, the measurement assembly comprises a load torque sensor connected in series in the force transmission path of the traction member for measuring the applied torque, displacement sensors at points A and B arranged at different heights on the pole body for measuring lateral displacement, an angular displacement sensor at point C arranged at the top end of the pole for measuring the torsion angle, and a deformation spectrum image acquisition device for non-contact acquisition of speckle image sequences on the surface of the pole.

[0010] Further, the system further comprises a processing assembly in communication connection with the load torque sensor, the displacement sensor, the angular displacement sensor, and the deformation spectrum image acquisition device, for synchronous reception and processing of multi-source test data.

[0011] In a second aspect, the technical solution adopted by the present application is as follows: a comprehensive test evaluation system for the torsional performance of a pole, comprising a data acquisition and processing unit in communication connection with a measurement assembly of a test device, for synchronous reception and processing of multi-source data from different sensors; a comprehensive evaluation unit in communication connection with the data acquisition and processing unit, with a built-in torsional performance decay prediction model; the torsional performance decay prediction model is configured to calibrate model parameters based on individual characteristic data extracted from the current test, and calculate and output a quantitative prediction result of the torsional performance decay of the pole.

[0012] In a third aspect, the technical solution adopted by the present application is as follows: a comprehensive test method for the torsional performance of a pole, comprising the following steps: S1: installing and centering a pole to be tested on a test device; S2: performing a comprehensive test and synchronously collecting multi-source test data by the data acquisition and processing unit; S3: extracting individual characteristic data for model calibration from the test data, including current effective torsional stiffness, fatigue performance parameters, and strain concentration coefficients; S4: inputting the individual characteristic data into the torsional performance decay prediction model to complete individual calibration of model parameters.

[0013] Further, in step S2, the comprehensive test comprises: S2a, a slow torque test, each level of torque is maintained until the deformation is stable, and the torque and the top end torsion angle are recorded synchronously, for extracting the current effective torsional stiffness and the maximum torsion angle under the safe load; S2b, a dynamic fatigue test, cyclic loading is performed at a set torque amplitude, and periodic pauses are made to measure the transient torsional stiffness.

[0014] Further, in step S3, the fatigue performance parameters are obtained from the dynamic fatigue test S2b, including the S-N curve parameters m and C fitted by destructive fatigue test, and the stiffness degradation rate η obtained by monitoring and fitting through non-destructive cyclic test.

[0015] Further, in step S4, the anti-torsion performance degradation prediction model predicts the anti-torsion bearing capacity value M u (t) is expressed as: .

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

[0017] The present application realizes the full-process, multi-dimensional quantitative characterization of the anti-torsion performance of a full-size pole under a near-real working condition through the test device and test method; by synchronously collecting torque, rotation angle, displacement, and full-field optical strain data, the system can automatically extract individual characteristic parameters such as the current effective anti-torsion stiffness, S-N curve parameters, stiffness degradation rate, and strain concentration coefficient, and based on this, a calibratable anti-torsion performance degradation prediction model is constructed, so as to not only accurately evaluate the current bearing capacity of the pole, but also quantitatively predict the anti-torsion performance degradation trend of the pole in the future service state, significantly improving the scientificity, comprehensiveness, and engineering practicability of the pole mechanical performance detection, and providing strong technical support for the safe operation and structure optimization of the power transmission line. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application can be further illustrated by the non-limiting embodiments shown in the accompanying drawings;

[0019] Figure 1 The present application is a schematic diagram of a test device;

[0020] Figure 2 The present application is a schematic diagram of a support clamp;

[0021] The accompanying drawings are as follows:

[0022] Base 1, test bench 2, pole 3, support clamp 4, skid 5, load torque sensor 6, deformation spectrum image acquisition device 7, torsion clamp 8, A point displacement sensor 9, B point displacement sensor 10, C point angular displacement sensor 11, processing assembly 12, electric tension tool 13, fixed pile 14. DETAILED DESCRIPTION

[0023] As shown in Figures 1-2 The test device mainly includes a base, which is built of reinforced concrete and has a steel structure test bench installed thereon, and a clamping support assembly installed on the test bench, which is used to fix and support the pole to be tested, and includes at least two support clamps for supporting the pole body and a torsion clamp arranged at the top end of the pole.

[0024] The electric pole to be measured is horizontally placed on two supporting clamps, each of which comprises a V-shaped supporting groove, a supporting roller is arranged in the supporting groove, the supporting roller is used for supporting the electric pole, a hydraulic lifting mechanism is arranged at the bottom of the supporting groove, and the electric pole can be lifted and lowered in the vertical direction and the height can be automatically adjusted.

[0025] A torsion clamp with a torsion arm is arranged at the top end of the electric pole to be measured, a traction member is connected to the end of the torsion arm, the end of the torsion arm is connected to a load torsion sensor through a traction steel cable, and an electric tension tool for applying tension to the traction member and a fixing pile for fixing the electric tension tool are further included.

[0026] The measurement assembly comprises a linear displacement sensor for monitoring lateral deflection of the pole body as shown in Figure 1 A C-point angular displacement sensor for measuring a torsion angle, and a deformation spectrum image acquisition device for observing a pole observation area, cooperating with surface speckle spraying to realize full-field strain field reconstruction.

[0027] The system of the application automatically extracts individual characteristic parameters for model calibration in the test, including:

[0028] The current effective torsional stiffness K test and the maximum torsional deformation angle θ test under the safety load extracted from the slow torque test, the S-N curve stress-life curve parameters and the stiffness degradation rate fitted from the dynamic fatigue test, and the strain concentration coefficient ξ identified from the DIC full-field deformation data.

[0029] Wherein K test and the safety load torsion angle θ test are extracted as follows: the electric tension tool is controlled by the system to apply a stepped torque T i (i=1, 2,..., n) to the electric pole, each load is maintained until the deformation is stable; the torque T i and the corresponding top end torsion angle θ i of the electric pole at each stable time are recorded synchronously by the torque sensor and the C-point angular displacement sensor, forming n data pairs (T i , θ i ).

[0030] The calculation formula is as follows:

[0031] The maximum torsion angle θ test: Set a safety load T safe , usually the design torque or the historical maximum service torque. In the test data, find the maximum torque value T i and its corresponding angle θ safe of T max,safe ≤T max,safe , that is, θ max,safe as θ test .

[0032] Second, the dynamic fatigue test is fitted to quantify the performance attenuation of the electric pole under the cyclic torque. According to the different purposes of the test, the system extracts two types of key data, namely the S-N curve parameters and the stiffness degradation rate. Among them, the S-N curve parameters are obtained by destructive fatigue test, and the stiffness degradation rate is obtained by non-destructive cyclic test.

[0033] When the intrinsic fatigue resistance of the electric pole material or configuration needs to be obtained, the S-N curve parameters are obtained, which is suitable for new product research and development, type test and other scenarios that allow destructive test. At this time, the system controls the electric tension tool, and under a plurality of different torque amplitude levels S j , respectively, carries out fatigue test until the test piece is destroyed or cracks appear, and records the failure cycle number N f j corresponding to each stress level.

[0034] A set of data pairs (S j , N f j ) are obtained. The system uses a general fatigue life model for fitting:

[0035]

[0036] Among them, the slope-related parameter m and the intercept-related parameter C obtained by linear regression fitting logS - logN f data are the S-N curve parameters representing the fatigue resistance of the electric pole.

[0037] When the cumulative damage state of the in-service electric pole needs to be evaluated or the durability monitoring is carried out, the stiffness degradation rate is obtained, and the test is usually carried out under a non-destructive torque amplitude.

[0038] The system carries out long-time test under the set constant or variable amplitude cyclic torque S a . During the test, the system periodically pauses the dynamic loading, and applies a slow torque from small to large every N k times of cycle, and synchronously measures the torque and angle relationship.

[0039] Through the measurement of torque and angle relationship each time, an instantaneous torsional stiffness K k, K k The calculation method is the same as K test , and the sequence of stiffness changes with the number of cycles K k (N k ) is obtained. The attenuation curve is fitted with a function:

[0040] The attenuation index η obtained by fitting is defined as the stiffness degradation rate of the pole under a certain load, which directly quantifies the speed of damage accumulation.

[0041] Finally, regarding the strain concentration coefficient ξ, its purpose is to quantify the local weakness or initial damage state of the pole caused by material, process or historical service, and the safety load T safe During the holding stage, the DIC optical measurement system is started to continuously collect speckle images of the observation area surface of the pole, and the ε vm (x,y) is calculated and derived by comparing images.

[0042] On the strain cloud map, the system automatically finds the local area with a significantly higher average strain level than other areas, extracts its maximum strain value ε max ; At the same time, representative points are selected in the uniform deformation section of the pole body, and the average nominal strain value ε nominal is calculated. The strain concentration coefficient ξ is defined as the ratio of the two:

[0043] The coefficient ξ≥1, the larger the value, the more significant the local weakness effect, which will be correspondingly reduced in the torsional performance attenuation prediction model.

[0044] In summary, the system will predict the torsional carrying capacity of the pole at time t Mu(t), which is expressed as the torsional performance attenuation prediction model:

[0045]

[0046] Where: M u0 is the initial ultimate torque;

[0047] , t is the service life, T is the design reference period, λ and α are degradation coefficients. The ratio of the current stiffness K test measured in this test to the design initial stiffness K0 is used to inversely calibrate the actual λ value of the pole, ;

[0048] The damage caused by n i times of torque amplitude S i is defined as d i =n i / N i , where N iThe failure cycle number at S i i under the S-N curve determined according to the dynamic fatigue test this time. The total damage D = ∑d fatigue . Then the fatigue reduction function can be expressed as: f (D) = 1 - β D where β is the damage sensitivity coefficient, which can be calibrated by the relationship between the stiffness drop and the cycle number in this fatigue test;

[0049] f damage (ξ) is a correction term based on the DIC detection results this time. If DIC analysis does not find obvious damage concentration, then ξ = 1, f damage (1) = 1. If the local strain concentration coefficient is identified as ξ (> 1), it can be mapped as a bearing capacity reduction coefficient: f damage (ξ) = ξ - γ, where γ is a material constant.

[0050] The above has carried out the detailed introduction to the present application. The description of the specific embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.​

Claims

1. A comprehensive test device for the torsional resistance of a pole, characterized by: The utility model relates to a test device for testing the torsional performance of electric poles, comprising a base, provided with a test bench, on which a clamping support assembly is installed for fixing and supporting the electric pole to be tested, comprising at least two support clamps for supporting the pole body and a torsional clamp with a torsional arm provided at the top end of the electric pole; the support clamp comprises a lifting hydraulic rolling support, which comprises a V-shaped bracket, a hydraulic mechanism for lifting the V-shaped bracket, and a supporting roller rotatably arranged in the V-shaped bracket; a torque loading assembly for applying torque to the electric pole through the torsional clamp; a measurement assembly for collecting torque, displacement, angle and image data during the test.

2. The pole torsional performance comprehensive test device according to claim 1, characterized in that: the torque loading assembly comprises a traction member connected to the end of the torsional arm, an electric tension tool for applying tension to the traction member, and a fixing pile for fixing the electric tension tool.

3. The device according to claim 2, characterized in that: the measurement assembly comprises a load torque sensor connected in the force transmission path of the traction member for measuring the applied torque; A point and B point displacement sensors arranged at different heights of the pole body for measuring lateral displacement; a C point angle displacement sensor arranged at the top end of the electric pole for measuring the torsional angle; a deformation spectrum image acquisition device for non-contact acquisition of speckle image sequences on the surface of the electric pole.

4. The pole torsional performance comprehensive test device according to claim 3, characterized in that: It also comprises a processing assembly in communication with the load torque sensor, the displacement sensor, the angle displacement sensor and the deformation spectrum image acquisition device for synchronous reception and processing of multi-source test data.

5. A system for evaluating the torsional performance of an electric pole, characterized by: The utility model relates to a test device for testing the torsional performance of electric poles, comprising a data acquisition and processing unit in communication with the measurement assembly of the test device for synchronous reception and processing of multi-source data from different sensors; a comprehensive evaluation unit in communication with the data acquisition and processing unit, which is provided with a torsional performance decay prediction model; the torsional performance decay prediction model is configured to calibrate the model parameters based on the individual characteristic data extracted from the current test, and calculate and output the torsional performance decay quantitative prediction result of the electric pole.

6. A method for comprehensive testing of the torsional resistance of an electric pole, characterized in that: The utility model relates to a test device for testing the torsional performance of electric poles, comprising S1: installing and centering the electric pole to be tested on the test device; S2: performing comprehensive test and synchronously collecting multi-source test data by the data acquisition and processing unit; S3: extracting individual characteristic data for model calibration from the test data, including current effective torsional stiffness, fatigue performance parameters and strain concentration coefficient; S4: inputting the individual characteristic data into the torsional performance decay prediction model to complete the individual calibration of the model parameters.

7. The method according to claim 6, characterized in that: In step S2, the comprehensive test comprises S2a, slow torque test, each level of torque is maintained until the deformation is stable, and the torque and top end torsional angle are recorded synchronously, which are used to extract the current effective torsional stiffness and the maximum torsional angle under the safe load; S2b, dynamic fatigue test, cyclic loading is carried out under the set torque amplitude, and periodic pause is carried out to measure the transient torsional stiffness. 8.The comprehensive test device and evaluation system and method for the torsional performance of a pole according to claim 7, characterized in that: In step S3, the fatigue performance parameters are obtained from the dynamic fatigue test S2b, including the S-N curve parameters m and C fitted by destructive fatigue test, and the stiffness degradation rate η obtained by monitoring and fitting through non-destructive cyclic test.

9. A method of testing a power pole for torsional force, the method comprising: applying a torsional force to the power pole; and measuring a deflection of the power pole. In step S4, the anti-torsion performance degradation prediction model predicts the anti-torsion carrying capacity value M of the electric pole at time t u (t) is expressed as: 。

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