A method for evaluating the service life of a crane wire rope
Patent Information
- Application Number
- CN202611073950.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-20
- Publication Date
- 2026-11-03
AI Technical Summary
Existing technologies treat wire rope strand signals and vibration interference as noise and filter them out, resulting in damage signal distortion, affecting the accuracy of assessment, and failing to make full use of the differences in signal spatial distribution patterns for accurate damage identification and assessment.
An even number of Hall effect sensors are arranged circumferentially along the wire rope to form a circumferential amplitude sequence. By extracting the axisymmetric attenuation component as the damage signal component, the spatial domain separation of the damage signal and the interference signal is achieved, and accurate damage characteristic parameters are obtained.
It achieves complete preservation of damage signals, avoids energy loss caused by filtering operations, and can accurately assess the current cumulative damage status and remaining life of the wire rope, providing safe and effective life prediction.
Smart Images
Figure CN123030943A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of wire rope life assessment, and in particular to a method for assessing the life of crane wire ropes. Background Technology
[0002] As the core flexible component of a crane's hoisting mechanism, the wire rope bears the heavy responsibility of directly lifting loads. Its service reliability is fundamental to the safe operation of the crane. During use, wire ropes are subjected to the coupled effects of multiple loads, including alternating tension, bending, wear, and corrosion, inevitably leading to progressive damage such as wire breakage, wear, and rust. If this damage accumulates beyond its limit and is not replaced in time, it can easily cause sudden breakage accidents, resulting in significant casualties and property damage. Therefore, conducting scientific and accurate life assessments of crane wire ropes is crucial for ensuring equipment operational safety, optimizing maintenance strategies, and reducing operating costs.
[0003] In the field of nondestructive testing of wire ropes, magnetic flux leakage testing is widely recognized as the most effective method for detecting wire rope damage due to its high sensitivity to defects in ferromagnetic materials and its engineering applicability. Its basic principle is to magnetize the wire rope. When defects such as broken wires or wear exist, the cross-sectional area of the magnetic circuit at the defect changes, causing magnetic lines of force to escape from the wire rope surface, forming a leakage magnetic field. By collecting the leakage magnetic field signal using magnetically sensitive elements such as Hall effect sensors, the presence and extent of damage can be inferred.
[0004] Extensive research has focused on improving detection accuracy and damage identification capabilities in magnetic flux leakage (MFL) detection technology. Regarding sensor placement, existing technologies employ Hall effect sensor arrays uniformly distributed around the circumference of the wire rope to capture three-dimensional radial MFL information on the rope surface. In signal processing, current technologies primarily face challenges from interference signals, including periodic strand wave signals generated by the inherent twisting structure of the wire rope, and interference signals generated during rope operation due to swaying and vibration. To eliminate strand wave signals, existing technologies have designed parameter-adaptive spatial notch filters, converting defect signals into grayscale images and then using two-dimensional image processing methods for feature extraction and damage identification. Other technologies employ multi-channel signal phase shifting to weaken the MFL detection signal. For vibration interference, existing technologies utilize filtering and noise reduction methods.
[0005] However, a deeper analysis of existing technical solutions reveals a long-overlooked systemic flaw in their fundamental signal processing logic. Existing technologies employ filtering or attenuation strategies when processing wire rope signals and vibration interference. Whether it's spatial notch filters, multi-channel signal phase shifting, or various filtering and noise reduction methods, they all essentially treat signals generated by the inherent structure of the wire rope or vibration signals generated during operation as noise and attempt to eliminate them.
[0006] However, the strand wave signal and the wire breakage damage signal of the wire rope overlap in both the time and frequency domains. While filtering methods weaken the strand wave signal, they also cause energy loss in the wire breakage signal, leading to a decrease in the accuracy of damage assessment. More importantly, the periodic signals generated by the wire rope's twisting structure contain spatial position information; the vibration signals during operation contain information about operational stability. Existing technologies, after filtering or weakening these signals, retain only a single dimension of information: the damage signal. This fails to fully utilize the differences in the spatial distribution patterns of different signals to achieve more accurate damage identification and assessment. Summary of the Invention
[0007] Therefore, the purpose of this application is to overcome the problem that the existing technology filters out both the inherent twisting signal and vibration signal of the wire rope as noise, which leads to the distortion of the damage signal. This application provides a method for assessing the life of crane wire ropes, which can separate and extract the damage signal and the interference signal in the spatial domain by using the component with axisymmetric decay in the circumferential amplitude sequence as the damage signal component, thereby avoiding the distortion of the damage signal and obtaining accurate damage characteristic parameters to assess the remaining life of the wire rope.
[0008] To solve the above-mentioned technical problems, this application provides a method for assessing the life of a crane wire rope, wherein an even number of Hall sensor elements are arranged along the circumference of the wire rope, and the number is at least four. Each Hall sensor element is installed at an equal angle in the same detection section to collect the leakage magnetic field signal generated on the surface of the wire rope due to damage.
[0009] The lifespan assessment method includes:
[0010] A circumferential amplitude sequence is formed based on the multiple leakage magnetic signals distributed along the circumference of the wire rope.
[0011] The component in the circumferential amplitude sequence that exhibits axisymmetric attenuation is taken as the damage signal component of each channel, and the damage characteristic parameters are determined based on the damage signal component.
[0012] The current cumulative damage state of the wire rope is determined based on the damage characteristic parameters; the cumulative load spectrum is determined based on the tensile force signal borne by the wire rope; and the remaining load cycle number is determined based on the current cumulative damage state and the cumulative load spectrum.
[0013] The above-mentioned technical solution of this application has the following advantages over the prior art:
[0014] The crane wire rope life assessment method described in this application can separate and extract damage signals and interference signals in the spatial domain by using the axisymmetrically attenuating component in the circumferential amplitude sequence as the damage signal component, avoiding damage signal distortion, and obtaining accurate damage characteristic parameters to assess the remaining life of the wire rope. Specifically:
[0015] First, an even number of Hall effect sensors arranged at equal angles along the circumference of the wire rope are used to collect the leakage magnetic field signal generated on the surface of the wire rope due to damage. A circumferential amplitude sequence is formed based on the multiple leakage magnetic field signals distributed along the circumference of the wire rope. Then, the axisymmetrically attenuating component in the circumferential amplitude sequence is used as the damage signal component of each channel. It is evident that the damage signal component extraction process in this application does not lose energy due to filtering, and weak damage signals are completely preserved, avoiding the problem of missed detection caused by filtering. Furthermore, damage characteristic parameters are determined based on the damage signal components, resulting in pure and complete damage characteristic parameters. Finally, the current cumulative damage state of the wire rope is determined based on the damage characteristic parameters, the cumulative load spectrum is determined based on the tensile force signal borne by the wire rope, and the remaining load cycle number is determined based on the current cumulative damage state and the cumulative load spectrum. Therefore, this application, by combining the load history reflected by the tensile force signal borne by the wire rope, can accurately assess the current cumulative damage state of the wire rope and predict its remaining load cycle number.
[0016] Furthermore, to address the challenge of finding a strictly symmetrical axis due to the coexistence of multiple damages and the superposition of leakage magnetic fields leading to complex circumferential amplitude distributions in the later stages of wire rope service in practical engineering, this application, based on the physical understanding that the dominant damage contributes more to the total leakage magnetic field, selects the candidate symmetrical channel direction with the smallest sum of amplitude deviations as the final symmetrical channel direction. Although it cannot completely separate the secondary damage components, it can retain the main attenuation characteristics of the dominant damage. The life assessment results made based on the damage signal components extracted in this way are relatively safe and effective. Attached Figure Description
[0017] To make the content of this application easier to understand, the following detailed description is provided based on specific embodiments and accompanying drawings, wherein:
[0018] Figure 1 This is a flowchart illustrating a method for assessing the lifespan of crane wire ropes in an embodiment of this application.
[0019] Figure 2 This is a schematic diagram of one structure of the Hall sensor array in an embodiment of this application.
[0020] Figure 3 This is a schematic diagram of a circumferential amplitude sequence in an embodiment of this application.
[0021] Figure 4 This is a schematic diagram of the damage signal components in each channel direction in an embodiment of this application. Detailed Implementation
[0022] The present application will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present application, but the embodiments are not intended to limit the present application.
[0023] Example 1: This example introduces a method for assessing the lifespan of crane wire ropes.
[0024] In application, an even number of Hall effect sensors, with a minimum of four, are installed along the circumference of the wire rope. These sensors are mounted at equal angles within the same detection section to collect the leakage magnetic field signal generated on the wire rope surface due to damage. For details, refer to [reference needed]. Figure 2 A Hall sensor array is formed by setting N Hall sensor elements. The included angle between two adjacent Hall sensor elements is 360° / N, where N is an even number from 4 to 16. Preferably, N is 8. When N=8, the included angle between adjacent Hall sensor elements is 45°.
[0025] In practical applications, each Hall sensor element is a linear Hall element, with its sensitive surface facing the surface of the wire rope. That is, the sensitive direction of each Hall sensor element points radially towards the central axis of the wire rope at its location, used to collect the radial leakage magnetic field component emitted from the surface of the wire rope due to damage. Each Hall sensor element operates independently, outputting a voltage signal proportional to the magnetic induction intensity perpendicular to its sensitive surface. Furthermore, a magnetizing device is installed upstream of the Hall sensor elements along the wire rope's running direction to saturate the wire rope with magnetization; details will not be elaborated here.
[0026] In practice, vibration sensors, such as accelerometers, are installed at the bearing seats of the rotating parts around which the wire rope winds to collect vibration signals during the wire rope's operation. A load sensor is installed at the fixed end of the wire rope to collect real-time tension signals. The load sensor's range is greater than or equal to 1.5 times the crane's rated load.
[0027] In some embodiments, the life assessment method for crane wire ropes includes: steps SS1 to SS3, referring to... Figure 1 Furthermore, life assessment methods may also include: early warning procedures.
[0028] Step SS1: Based on the multi-channel leakage magnetic signals distributed along the circumference of the wire rope, form a circumferential amplitude sequence.
[0029] In application, during the operation of the wire rope, each Hall sensor continuously outputs a voltage signal corresponding to the leakage magnetic flux density in its circumferential direction. Since each Hall sensor operates independently, and each Hall sensor outputs an independent voltage signal, multiple voltage signals distributed along the circumference of the wire rope can be obtained simultaneously.
[0030] In practical applications, the method for forming the circumferential amplitude sequence includes: step SS11.
[0031] Step SS11: Collect the voltage signals independently output by each Hall sensor element at the same time, and arrange the amplitude of each voltage signal according to the arrangement order of each Hall sensor element in the circumferential direction of the wire rope to form a circumferential amplitude sequence along the circumference of the wire rope.
[0032] Step SS2: Take the component in the circumferential amplitude sequence that exhibits axisymmetric attenuation as the damage signal component of each channel, and determine the damage characteristic parameters based on the damage signal component.
[0033] In application, when a localized damage occurs in a wire rope, such as a broken wire, the cross-sectional area of the magnetic circuit at the damaged point decreases, and magnetic lines of force escape from the damaged area onto the wire rope surface, forming a leakage magnetic field. The distribution characteristics of the leakage magnetic field along the circumference of the wire rope are as follows: the magnetic induction intensity is greatest facing the damage direction, gradually attenuating towards both sides along the circumference, and the magnetic induction intensity is smallest facing away from the damage direction, exhibiting an axisymmetric distribution about the damage direction. In contrast, during wire rope operation, the overall displacement caused by swaying or vibration results in changes in the distance between each channel's Hall effect sensor element and the wire rope surface. The change in the leakage magnetic field signal of each channel varies with the cosine of the angle between the channel direction and the displacement direction, and its spatial distribution pattern differs from the axisymmetric attenuation characteristic of the damage leakage magnetic field. Based on this, this embodiment extracts the axisymmetrically attenuating component from the circumferential amplitude sequence as the damage signal component, thereby achieving spatial separation of the damage signal and interference signal.
[0034] In some embodiments, the method for determining the damage signal component includes steps SS21 to SS23.
[0035] Step SS21: In the circumferential amplitude sequence, select the channel direction with the largest voltage signal amplitude as the candidate symmetrical channel direction.
[0036] In application, if the voltage signal amplitude of multiple channel directions is at its maximum value at the same time, the channel direction with the smaller sequence number in the corresponding circumferential amplitude sequence is selected first as the candidate symmetrical channel direction; if the channel direction does not meet the symmetry condition of step SS22 below, the remaining channel directions with the same maximum amplitude are selected in ascending order of sequence number, and the verification of step SS22 is performed respectively to find the candidate symmetrical channel direction that meets the symmetry condition.
[0037] Step SS22: Using the candidate symmetrical channel direction as the axis of symmetry, compare the voltage signal amplitudes of each pair of symmetrical channels in the circumferential amplitude sequence one by one: if the amplitude deviation of each pair of symmetrical channels is less than or equal to a preset deviation threshold, then the candidate symmetrical channel direction is determined as the final symmetrical channel direction.
[0038] For details, please refer to Figure 3 For eight Hall effect sensors, the symmetrical channels symmetrical about the first channel direction include: the second and eighth channel directions, the third and seventh channel directions, and the fourth and sixth channel directions. The amplitude deviation is calculated for each pair of symmetrical channels. ; ; .in, This represents the voltage signal amplitude in the second channel direction. This represents the voltage signal amplitude in the 8th channel direction. This represents the voltage signal amplitude in the third channel direction. This represents the voltage signal amplitude in the 7th channel direction. This represents the voltage signal amplitude in the fourth channel direction. This refers to the voltage signal amplitude in the sixth channel direction. In application, the preset deviation threshold can be determined based on the measurement noise level and detection accuracy requirements of the Hall sensor element. Furthermore, the preset deviation threshold is the product of the standard deviation of the background noise and the confidence coefficient. The confidence coefficient is between 3 and 5. For example, in this embodiment, the standard deviation of the background noise in each channel is approximately 5mV, and with a confidence coefficient of 3, the preset deviation threshold can be 15mV.
[0039] In actual operation, taking the candidate symmetrical channel direction as the axis of symmetry, when comparing the voltage signal amplitudes of each pair of axisymmetric channels in the circumferential amplitude sequence one by one: if the amplitude deviation of each pair of symmetrical channels is less than or equal to a preset deviation threshold, then the current damage is determined to be a single damage mode, and the candidate symmetrical channel direction is determined as the final symmetrical channel direction. If the amplitude deviation of any symmetrical channel is greater than the preset deviation threshold, it indicates that the current candidate symmetrical channel direction does not meet the axisymmetric condition. Then, the channel direction with the second largest voltage signal amplitude is selected as the new candidate symmetrical channel direction, and the amplitude comparison is repeated until the amplitude deviation of each symmetrical channel is less than or equal to the preset deviation threshold.
[0040] In practical applications, after traversing the channel direction of each voltage signal amplitude in the circumferential amplitude sequence as a candidate symmetrical direction, if no channel direction can satisfy that the amplitude deviation of all symmetrical channels is less than or equal to a preset deviation threshold, then the current damage is determined to be a multi-damage mode, and the candidate symmetrical channel direction with the smallest sum of amplitude deviations of each pair of symmetrical channel directions among all candidate symmetrical channel directions is selected as the final symmetrical channel direction.
[0041] Step SS23: Take the final symmetrical channel direction as the damaged channel direction, and take the voltage signal amplitude in the final symmetrical channel direction as the reference amplitude; take the angle between each channel and the final symmetrical channel direction as the variable, and determine the attenuation amplitude of each channel according to the attenuation law that the voltage signal amplitude decreases as the angle increases, and take the attenuation amplitude as the damaged signal component.
[0042] In application, the attenuation law is that the attenuation amplitude of the two channels in each pair of symmetrical channel directions is equal, and the attenuation amplitude of each channel decreases monotonically as the angle between the channel and the final symmetrical channel direction increases.
[0043] In practical applications, refer to Figure 4 For 8 Hall effect sensors, when the direction of the first channel is the final symmetrical channel direction, ; ; ; ; .in, This represents the voltage signal amplitude in the first channel direction. This represents the voltage signal amplitude in the second channel direction. This represents the voltage signal amplitude in the 8th channel direction. This represents the voltage signal amplitude in the third channel direction. This represents the voltage signal amplitude in the 7th channel direction. This represents the voltage signal amplitude in the fourth channel direction. This represents the voltage signal amplitude in the 6th channel direction. This refers to the voltage signal amplitude in the 5th channel direction; The amplitude of the damage signal component in the first channel direction; The amplitude of the damage signal component in the second channel direction; This represents the amplitude of the damage signal component in the 8th channel direction; This represents the amplitude of the damage signal component in the third channel direction; The amplitude of the damage signal component in the 7th channel direction; This represents the amplitude of the damage signal component in the fourth channel direction; This represents the amplitude of the damage signal component in the 6th channel direction; This represents the amplitude of the damage signal component in the 5th channel direction.
[0044] In some embodiments, the damage characteristic parameters include the number of broken wires and / or the wear cross-sectional area loss rate.
[0045] In some embodiments, the method for determining the number of broken wires includes step SS26.
[0046] Step SS26: Perform peak detection on the damage signal components. If the amplitude of the damage signal component in any channel is greater than the amplitude of the damage signal components in the two adjacent channels on both sides of the channel, and the amplitude of the damage signal component in the channel is greater than 3 times the average amplitude of the damage signal components in the two adjacent channels on both sides of the channel, increment the number of broken wires by one.
[0047] In application, among the adjacent channels on both sides, the first channel and the Nth channel are adjacent in the circumferential direction.
[0048] In practical applications, the initial value of the number of broken wires is 0. The number of channels that meet the conditions in step SS26 is counted. Each time a channel is detected, the number of broken wires is incremented by 1. The final statistical value is the number of broken wires.
[0049] In actual implementation, if , ,and Then judge The local peaks are anomalies caused by damage, rather than by signal noise or small fluctuations, so add 1 to the number of broken wires.
[0050] In some embodiments, the method for extracting the wear cross-sectional area loss rate includes steps SS271 to SS274.
[0051] Step SS271: Obtain the reference envelope area of a standard wire rope of the same specifications as the wire rope to be tested.
[0052] In application, the reference envelope area is the envelope area of the damage signal component of a standard steel wire rope of the same specification as the steel wire rope under test without damage. It can be calculated according to the method of calculating the first envelope area in this application, which will not be elaborated here.
[0053] Step SS272: Take the amplitude of the damage signal component of each channel of the wire rope under test as the polar radius and the circumferential angle of each channel as the polar angle to form a sequence of amplitude points in polar coordinates.
[0054] When applied, the circumferential angle includes: In the formula, For the channel number, ; For the first The circumferential angle of each channel.
[0055] Step SS273: Connect adjacent amplitude points in order of increasing circumferential angle, connect the last amplitude point with the first amplitude point to form a closed envelope curve, and take the area of the polygon enclosed by the closed envelope curve as the first envelope area.
[0056] In application, the first amplitude point is connected to the second amplitude point, the second amplitude point is connected to the third amplitude point, the third amplitude point is connected to the fourth amplitude point, and so on, with the last amplitude point connected to the first amplitude point.
[0057] In practical applications, In the formula, The area of the first envelope; For the first The amplitude of the damage signal components in each channel direction; For the first The amplitude of the damage signal components in each channel direction, ; For the first The first channel and the first The angle between the channels.
[0058] Step SS274: The reduction ratio of the first envelope area relative to the reference envelope area is taken as the wear cross-sectional area loss rate.
[0059] In application, the wear cross-sectional area loss rate = (reference envelope area - first envelope area) / reference envelope area × 100%.
[0060] Step SS3: Determine the current cumulative damage state of the wire rope based on the damage characteristic parameters; determine the cumulative load spectrum based on the tensile force signal borne by the wire rope; and determine the remaining load cycle number based on the current cumulative damage state and the cumulative load spectrum.
[0061] In some embodiments, the method for determining the current cumulative damage state includes steps SS31 to SS32.
[0062] Step SS31: When the damage characteristic parameter includes the number of broken wires, a first cumulative damage degree is obtained using the number of broken wires based on the first correspondence between the number of broken wires and the cumulative damage degree; when the damage characteristic parameter includes the wear cross-sectional area loss rate, a second cumulative damage degree is obtained using the wear cross-sectional area loss rate based on the second correspondence between the wear cross-sectional area loss rate and the cumulative damage degree.
[0063] When applied, the cumulative damage value ranges from 0 to 1. When the cumulative damage value is 0, it means that the wire rope is in an undamaged state; when the cumulative damage value is 1, it means that the wire rope has reached the failure threshold and should be scrapped and replaced immediately; when the cumulative damage value is greater than 0 and less than 1, it means that the wire rope is in a partially damaged state, and the larger the cumulative damage value, the more serious the damage.
[0064] In practical applications, the method for constructing the first correspondence includes: setting the cumulative damage degree corresponding to the number of broken wires to 0 when the number of broken wires is 0; setting the cumulative damage degree corresponding to the number of broken wires greater than or equal to 10% of the total number of wires to 1; and determining the cumulative damage degree corresponding to each number of broken wires in the middle by linear interpolation.
[0065] Furthermore, the total number of filaments = number of strands × number of filaments / strand. When the number of broken filaments is greater than 0 and less than 10% of the total number of filaments, the first cumulative damage level = number of broken filaments / (10% × total number of filaments).
[0066] In practical applications, the method for constructing the second correspondence includes: setting the cumulative damage degree corresponding to a wear cross-sectional area loss rate of 0 as 0; setting the cumulative damage degree corresponding to a wear cross-sectional area loss rate greater than or equal to 10% as 1; and determining the cumulative damage degree corresponding to each intermediate wear cross-sectional area loss rate by linear interpolation.
[0067] Furthermore, when the wear cross-sectional area loss rate is greater than 0 and less than 10%, the second cumulative damage degree = wear cross-sectional area loss rate / 10%.
[0068] Step SS32: If only the first cumulative damage value is obtained, then the first cumulative damage value is used as the current cumulative damage state; if only the second cumulative damage value is obtained, then the second cumulative damage value is used as the current cumulative damage state; if both the first and second cumulative damage values are obtained, then the larger of the first and second cumulative damage values is used as the current cumulative damage state.
[0069] In some embodiments, the cumulative load spectrum determination method includes steps SS33 to SS35.
[0070] Step SS33: Starting from the time the wire rope is put into use, continuously collect the tension signal borne by the wire rope, and record the amplitude of the tension signal at each moment in chronological order to form a tension signal sequence.
[0071] Step SS34: Analyze the tensile signal amplitude of the tensile signal sequence to identify each load cycle and record the maximum tensile signal amplitude corresponding to the load cycle.
[0072] In application, one complete load cycle corresponds to one complete lifting operation of the crane. It is the complete process of the wire rope going from being unloaded and bearing a load to being unloaded and returning to an unloaded state. The maximum tensile force signal amplitude of each load cycle reflects the magnitude of the load lifted during that cycle.
[0073] In practical applications, peak and valley value detection is performed on the tensile signal sequence. A three-point comparison method is used to extract all peak and valley values: For the i-th data point in the tensile signal sequence, if the amplitude of the i-th data point is simultaneously greater than the amplitudes of the (i-1)-th and (i+1)-th data points, then the amplitude of the i-th data point is determined to be a peak value. For the i-th data point in the tensile signal sequence, if the amplitude of the i-th data point is simultaneously less than the amplitudes of the (i-1)-th and (i+1)-th data points, then the amplitude of the i-th data point is determined to be a valley value.
[0074] After extracting all peak and valley values, adjacent peak and valley values are paired according to the pattern of their alternating appearance in time sequence to identify each complete load cycle. For each identified load cycle, the amplitude of the peak value in the load cycle is recorded as the maximum tensile signal amplitude of the load cycle.
[0075] Step SS35: Divide each load cycle into the corresponding load level interval according to the magnitude of the maximum tensile force signal, and count the number of load cycles in each load level interval to form a cumulative load spectrum.
[0076] In application, based on the crane's rated load, the range of the tension signal amplitude is divided into K equally spaced load level intervals. Specifically, the tension signal amplitude is divided into K levels from 0 to the rated load, and the preferred value of K is 10.
[0077] In practical applications, the number of load cycles for each load level range within each unit time period is counted to form the cumulative load spectrum from when the wire rope was put into use to the current moment.
[0078] In some embodiments, the method for determining the number of remaining load cycles includes steps SS36 to SS38.
[0079] Step SS36: If the current cumulative damage status is equal to 0, then the number of cycles of the wire rope rated load is used as the number of cycles of the remaining load.
[0080] In application, the rated load cycle number is the fatigue life of the wire rope of the specified specification under rated load, which can be obtained by consulting the product technical manual.
[0081] Step SS37: If the current cumulative damage state is equal to 1, then the remaining load cycle count is 0. Step SS38: If the current cumulative damage state is greater than 0 and less than 1, then the cumulative cycle count for each load level interval in the cumulative load spectrum is counted, and based on the cumulative cycle count and the current cumulative damage state, the remaining load cycle count required to reach the failure threshold is determined.
[0082] When applied, reaching the failure threshold means reaching a state where the current cumulative damage equals 1.
[0083] In practical applications, the number of remaining load cycles includes the following formula:
[0084] ;
[0085] In the formula, The remaining load cycle count; This represents the current cumulative damage status. This represents the cumulative number of loops.
[0086] In some embodiments, the life assessment method further includes an early warning step.
[0087] Specifically, the early warning steps include: issuing a wire rope replacement early warning signal when the estimated number of days of use corresponding to the remaining load cycles is less than the replacement cycle days of the wire rope. Further, the ratio of the remaining load cycles to the historical average daily load cycles is used as the estimated number of days of use. The replacement cycle days are preset by the wire rope user according to safety regulations.
[0088] Furthermore, the warning steps may also include: issuing a wire rope replacement warning signal when the number of broken wires is greater than or equal to 5% of the total number of wires.
[0089] Furthermore, the early warning step may also include: issuing a wire rope replacement warning signal when the wear cross-sectional area loss rate is greater than or equal to 5%. Obviously, the above embodiments are merely examples for clear illustration and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.
Claims
1. A method for assessing the lifespan of crane wire ropes, characterized in that, An even number of Hall effect sensors are provided along the circumference of the wire rope, with a minimum of four. Each Hall effect sensor is installed at an equal angle within the same detection section to collect the leakage magnetic field signal generated on the surface of the wire rope due to damage. The lifespan assessment method includes: A circumferential amplitude sequence is formed based on the multiple leakage magnetic signals distributed along the circumference of the wire rope. The component in the circumferential amplitude sequence that exhibits axisymmetric attenuation is taken as the damage signal component of each channel, and the damage characteristic parameters are determined based on the damage signal component. The current cumulative damage state of the wire rope is determined based on the damage characteristic parameters; the cumulative load spectrum is determined based on the tensile force signal borne by the wire rope; and the remaining load cycle number is determined based on the current cumulative damage state and the cumulative load spectrum.
2. The method for assessing the lifespan of crane wire ropes according to claim 1, characterized in that, The method for forming the circumferential amplitude sequence includes: At the same time, the voltage signals independently output by each Hall sensor element are collected, and the amplitude of each voltage signal is arranged according to the arrangement order of each Hall sensor element in the circumference of the wire rope to form a circumferential amplitude sequence along the circumference of the wire rope.
3. The method for assessing the lifespan of crane wire ropes according to claim 1, characterized in that, The method for determining the damage signal components includes: In the circumferential amplitude sequence, the channel direction with the largest voltage signal amplitude is selected as the candidate symmetrical channel direction; Using the candidate symmetrical channel direction as the axis of symmetry, the voltage signal amplitudes of each pair of symmetrical channels in the circumferential amplitude sequence are compared one by one: if the amplitude deviation of each pair of symmetrical channels is less than or equal to a preset deviation threshold, then the candidate symmetrical channel direction is determined as the final symmetrical channel direction. The direction of the final symmetrical channel is taken as the direction of the damaged channel, and the voltage signal amplitude in the direction of the final symmetrical channel is taken as the reference amplitude. The angle between each channel and the direction of the final symmetrical channel is taken as the variable. According to the attenuation law that the voltage signal amplitude decreases as the angle increases, the attenuation amplitude of each channel is determined, and the attenuation amplitude is taken as the damaged signal component. The attenuation law states that the attenuation amplitudes of the two channels in each pair of symmetrical channel directions are equal, and the attenuation amplitude of each channel decreases monotonically as the angle between the channel and the final symmetrical channel direction increases.
4. The method for assessing the lifespan of crane wire ropes according to claim 3, characterized in that, When comparing the voltage signal amplitudes of each pair of axisymmetric channels in the circumferential amplitude sequence, with the candidate symmetrical channel direction as the axis of symmetry, the following steps are performed: If the amplitude deviation of any symmetrical channel is greater than the preset deviation threshold, the channel direction with the second largest voltage signal amplitude is selected as the new candidate symmetrical channel direction, and the amplitude comparison is performed again until the amplitude deviation of each symmetrical channel is less than or equal to the preset deviation threshold. After traversing the channel direction of each voltage signal amplitude in the circumferential amplitude sequence as a candidate symmetrical direction, if no channel direction can satisfy that the amplitude deviation of all symmetrical channels is less than or equal to a preset deviation threshold, then the candidate symmetrical channel direction with the smallest sum of amplitude deviations of all pairs of symmetrical channel directions among all candidate symmetrical channel directions is selected as the final symmetrical channel direction.
5. The method for assessing the lifespan of crane wire ropes according to claim 3, characterized in that, The damage characteristic parameters include the number of broken wires and / or the wear cross-sectional area loss rate; The method for determining the number of broken wires includes: Peak detection is performed on the damage signal components. In response to the fact that the amplitude of the damage signal component of any channel is greater than the amplitude of the damage signal components of the two adjacent channels on both sides of the channel, and the amplitude of the damage signal component of the channel is greater than 3 times the average amplitude of the damage signal components of the two adjacent channels on both sides of the channel, the number of broken wires is incremented by one; wherein, the initial value of the number of broken wires is 0. The method for extracting the wear cross-sectional area loss rate includes: Obtain the reference envelope area of a standard steel wire rope of the same specifications as the steel wire rope to be tested; The amplitude of the damage signal component of each channel of the wire rope under test is used as the polar radius, and the circumferential angle of each channel is used as the polar angle to form a sequence of amplitude points in polar coordinates. Connect adjacent amplitude points in order of increasing circumferential angle, connect the last amplitude point to the first amplitude point to form a closed envelope curve, and take the area of the polygon enclosed by the closed envelope curve as the first envelope area. The reduction ratio of the first envelope area relative to the reference envelope area is taken as the wear cross-sectional area loss rate.
6. The method for assessing the lifespan of crane wire ropes according to claim 1, characterized in that, The method for determining the current cumulative damage state includes: When the damage characteristic parameter includes the number of broken wires, a first cumulative damage degree is obtained using the number of broken wires based on a first correspondence between the number of broken wires and the cumulative damage degree; when the damage characteristic parameter includes the wear cross-sectional area loss rate, a second cumulative damage degree is obtained using the wear cross-sectional area loss rate based on a second correspondence between the wear cross-sectional area loss rate and the cumulative damage degree. If only the first cumulative damage value is obtained, then the first cumulative damage value is used as the current cumulative damage state; if only the second cumulative damage value is obtained, then the second cumulative damage value is used as the current cumulative damage state; if both the first and second cumulative damage values are obtained, then the larger of the first and second cumulative damage values is used as the current cumulative damage state.
7. The method for assessing the lifespan of crane wire ropes according to claim 6, characterized in that, The method for constructing the first correspondence includes: setting the cumulative damage degree corresponding to the number of broken wires to 0 when the number of broken wires is 0; setting the cumulative damage degree corresponding to the number of broken wires greater than or equal to 10% of the total number of wires to 1; and determining the cumulative damage degree corresponding to each number of broken wires in the middle by linear interpolation. The method for constructing the second correspondence includes: setting the cumulative damage degree corresponding to the wear cross-sectional area loss rate of 0 as 0; setting the cumulative damage degree corresponding to the wear cross-sectional area loss rate of 10% or more as 1; and determining the cumulative damage degree corresponding to each intermediate wear cross-sectional area loss rate by linear interpolation.
8. The method for assessing the lifespan of crane wire ropes according to claim 7, characterized in that, The method for determining the cumulative load spectrum includes: From the moment the wire rope is put into use, the tensile force signal borne by the wire rope is continuously collected, and the amplitude of the tensile force signal at each moment is recorded in chronological order to form a tensile force signal sequence. Analyze the tensile signal amplitude of the tensile signal sequence to identify each load cycle, and record the maximum tensile signal amplitude corresponding to the load cycle; Each load cycle is divided into the corresponding load level interval according to the magnitude of the maximum tensile force signal, and the number of load cycles in each load level interval is counted to form a cumulative load spectrum.
9. The method for assessing the lifespan of crane wire ropes according to claim 8, characterized in that, The method for determining the number of remaining load cycles includes: If the current cumulative damage status is equal to 0, then the number of cycles of the wire rope under rated load is taken as the number of cycles of the remaining load. If the current cumulative damage state is equal to 1, then the remaining load cycle count is 0; If the current cumulative damage state is greater than 0 and less than 1, then the cumulative number of cycles for each load level interval in the cumulative load spectrum is counted, and based on the cumulative number of cycles and the current cumulative damage state, the remaining number of load cycles required to reach the failure threshold is determined: ； In the formula, The remaining load cycle count; This represents the current cumulative damage status. This represents the cumulative number of loops.
10. The method for assessing the lifespan of crane wire ropes according to claim 9, characterized in that, The life assessment method also includes: When the estimated number of days of use corresponding to the remaining load cycle number is less than the replacement cycle number of the wire rope, a wire rope replacement warning signal is issued. Alternatively, when the number of broken wires is greater than or equal to 5% of the total number of wires, a wire rope replacement warning signal is issued; Alternatively, when the wear cross-sectional area loss rate is greater than or equal to 5%, a wire rope replacement warning signal will be issued.