A method for testing the dynamic operation safety of a crane

Abstract

The present application relates to gantry crane dynamic operation safety test technical field, especially a kind of crane dynamic operation safety test method, including step 1, multidimensional static calibration;Step 2, fault coupling simulation;Step 3, structured data processing;Step 4, coupling determination;Step 5, root source tracing;Step 6, targeted rectification.The present application is aimed at the structure and working condition of gantry crane car unidirectional travel, girder-leg rigid welding, long track bearing, double-side braking, open-air operation, designs multidimensional static calibration, fault coupling simulation and targeted rectification scheme.Break through the limitation of insufficient adaptability of gantry crane integrated structure in prior art, solve the distortion problem caused by ignoring equipment properties.Aiming at the characteristics of large torsional stiffness of box girder of gantry crane, small torsional deformation and caused by internal defects or external uneven stress, progressive tracing of internal defect detection, external load investigation and connection state verification is adopted.

Description

Technical Field

[0001] This invention relates to the field of dynamic operation safety testing technology for gantry cranes, and in particular to a method for testing the dynamic operation safety of cranes. Background Technology

[0002] As a core heavy equipment in ports, storage yards and other similar settings, the dynamic balance performance of gantry cranes directly determines the safety and efficiency of operations.

[0003] Existing dynamic equilibrium testing technologies mostly revolve around traditional methods of detecting load, stress, and displacement, such as using strain gauges to collect stress in the main beam, laser vibration meters to monitor amplitude, and tension sensors to obtain wire rope tension, in order to determine whether the structure is in a state of mechanical equilibrium. However, these technologies have the following obvious shortcomings:

[0004] On the one hand, it focuses on conventional mechanical parameters (stress, displacement, load) without considering the asymmetric structural layout of the gantry crane and the influencing factors such as non-uniform load transfer under dynamic working conditions and the directional effect of environmental disturbances.

[0005] For example, patent application CN202310674571.2 (A tower crane mechanism bench test method and system) proposes to simulate the lifting and luffing operations of a tower crane under real working conditions through no-load tests, heavy-load tests, reliability tests, and full life-cycle tests, and to collect parameters such as temperature, vibration, and noise to evaluate the mechanism's performance and lifespan. However, the rigid connection between the main beam and the outriggers of a gantry crane has stress concentration bias, and the track side clearance deviation during trolley travel will cause lateral load shift, which will significantly disrupt the dynamic balance. The above-mentioned technology cannot complete this test.

[0006] On the other hand, the existing balance judgment standards are crude: existing technologies mostly use the absence of abnormal vibration and stress not exceeding the limit as the basis for balance judgment. For example, patent CN202310674571.2 stipulates that the noise of the rated load test should not be greater than 90dB and there should be no permanent deformation in the static load test. However, it is not applicable to the safety test of gantry cranes and cannot meet their high-precision dynamic balance control requirements.

[0007] Therefore, it is necessary to design a dynamic operation safety testing method and system specifically for gantry cranes. Summary of the Invention

[0008] To solve one of the above-mentioned technical problems, the present invention adopts the following technical solution: a method for testing the dynamic operation safety of a crane, comprising: Step 1, multi-dimensional static calibration: collecting the micro-texture of the wheel tread, residual stress of the main beam-outer leg weld, settlement gradient of the track foundation, environmental temperature and humidity correction coefficient, and brake shoe clearance of the trolley; once all parameters meet the standards, proceed to the next step.

[0009] Step 2, Fault Coupling Simulation: Simulate local steps on the wheel tread, local depressions in the track, uneven wear of the trolley brakes, and instantaneous gusts, while simultaneously collecting data on wheel contact stress distribution, track impact acceleration, main beam torsional deformation angle, and brake friction pad temperature field.

[0010] Step 3, Structured Data Processing: The collected wheel contact stress distribution is processed using a bilinear interpolation algorithm to obtain complete stress data; the track impact acceleration is subjected to a 500Hz low-pass filter to extract impact features; the main beam torsional deformation angle is denoised by moving average to ensure the accuracy of deformation; and the brake friction pad temperature field is analyzed by isotherm analysis to extract temperature parameters. After extracting the feature values ​​of the above four types of data, time alignment is performed based on the synchronous trigger signal to ensure that the alignment deviation is ≤1ms.

[0011] Step 4, Coupling Determination: Construct a multi-parameter model, introduce a large vehicle mass correction coefficient, and determine that the superposition coefficient ≥ 1.2 is unsafe;

[0012] Step 5, root cause analysis: Scanning electron microscopy to observe the tread morphology, stress wave analysis to measure main beam defects, and brake clearance detection to locate the microscopic and macroscopic root causes;

[0013] Step 6, targeted rectification: laser cladding repairs wheel texture, arc welding fills track depressions, brake shoe grinding, and retests dual parameters after rectification.

[0014] Based on any of the above technical solutions, the further optimization is as follows: the specific steps of the multi-dimensional static calibration in step 1 are as follows: (1) Micro-texture collection of wheel tread: the gantry crane trolley travels along a fixed track in one direction for a long time, and uneven texture wear is likely to occur in the outer 1 / 3 area of ​​the tread. A line laser scanning device is used to take one section every 15° along the circumference of the wheel, and 50 data points are collected radially in each section. The average depth of the texture valley is calculated, and the preset threshold is ≥0.8mm; if the valley depth is <0.8mm, it is marked as to be repaired, and laser texture addition is subsequently used. (1) Restore the texture, and retest after processing to ensure that the valley depth meets the standard. At the same time, the texture roughness Ra≤1.6μm is tested. (2) Collect residual stress of main beam-leg weld: The main beam and leg of the gantry crane are rigidly welded. The weld is prone to residual stress. Points are set at the top, middle and bottom within 20mm on both sides of the weld. The blind hole method is used to calculate the residual stress. The preset threshold is ≤150MPa. If the stress is >150MPa, vibration aging treatment is performed. After treatment, the measurement is repeated to ensure that the stress distribution uniformity is improved by 30%. At the same time, the ultrasonic flaw detector is used to detect the internal stress of the weld. To ensure no defects ≥1mm: (3) Track foundation settlement gradient collection: The track of the gantry crane is 10-50m long. Uneven foundation settlement can easily lead to wheel wear. Using a total station, set an elevation point every 3m along the entire length of the track, calculate the ratio of the settlement difference between adjacent points to the distance, and preset the threshold ≤0.5mm / m; if the gradient is >0.5mm / m, use epoxy resin grout to lift it. Pause for 30s every 0.5mm. After the gradient is retested and meets the standard, use a track ruler to check the flatness of the top surface of the track is ≤0.1mm; (4) Environmental temperature and humidity correction coefficient Data collection: Environmental parameters are collected using temperature and humidity sensors, and correction coefficients are calculated. If the deviation is greater than 2%, the material parameters in the subsequent judgment are adjusted, and the correction process is recorded to ensure traceability. (5) Collection of brake shoe clearance of the gantry crane: The gantry crane brakes with double brake shoes. Uneven clearance is prone to uneven wear. A feeler gauge is used to measure the clearance at 3 points at both ends and the middle of the brake shoe. The difference in clearance between the two brake shoes is calculated, and the preset threshold is ≤0.2mm. If the difference is greater than 0.2mm, the brake push rod stroke is adjusted to ensure that the clearance difference meets the standard. At the same time, the contact area of ​​the brake shoe is detected to be ≥80%.

[0015] Based on any of the above technical solutions, the further optimization is that the specific details of the fault coupling simulation in step 2 include: (1) Simulation of local steps on the wheel tread: The unidirectional movement of the gantry crane trolley leads to steps easily appearing on the outer side of the tread. A precision grinding machine is used to grind a 3mm deep and 50mm wide step in the outer 1 / 3 area of ​​the wheel tread. The step transition radius is ≤1mm. After grinding, a surface roughness tester is used to ensure that the surface Ra of the step is ≤3.2μm. At the same time, a laser diameter gauge is used to measure the wheel diameter to ensure that the diameter deviation at the step is ≤0.1mm; (2) Simulation of local depressions in the track: The long-term load on the track of the gantry crane is prone to local depressions. In the middle of the track span, an arc weld is used to weld a 2mm deep and 100mm long groove. After welding, an angle grinder is used to grind the edge of the groove and the transition radius is ≤1mm. (2) Angle ≤ 0.5mm, after grinding, use a track ruler to check the flatness of the recessed area ≤ 0.2mm, and at the same time use an ultrasonic thickness gauge to check the track thickness to ensure that the recess does not cause the thickness to exceed the standard; (3) Large trolley brake wear simulation: the brake shoes on both sides of the gantry crane are prone to uneven wear due to uneven wear. Adjust the gap between the brake shoe on one side and the wheel to 1.5 times the design value, use a feeler gauge to measure the gap on both sides to ensure that the gap on one side is more than 50% larger than the other side, and at the same time check the contact area of ​​the brake shoe on the side of uneven wear ≤ 70% to avoid the simulation distortion of brake failure due to the small contact area; (4) Instantaneous gust simulation: the gantry crane is prone to instantaneous gusts when operating outdoors. Use wind tunnel equipment, and control the wind speed through PLC to quickly increase from the ambient wind speed to 20m / s, and then restore to the ambient wind speed after 5s. The wind speed control accuracy is ±0.5m / s.

[0016] At the same time, a three-dimensional anemometer is used to monitor the top, middle and bottom of the main beam to ensure that the uniformity deviation of the gust in the height direction of the main beam is ≤5%, and to avoid test errors caused by uneven wind speed; (5) Multi-parameter synchronous acquisition: For the coupling characteristics of the gantry crane wheel-track-main beam-brake, synchronous acquisition is performed: Contact stress: Array piezoelectric sensors are laid along the track with a spacing of ≤5mm and a sampling rate of 10000Hz; Impact acceleration: Acceleration sensors are installed 100mm on both sides of the depression with a sampling rate of 10000Hz; Torsional deformation angle: 4 laser displacement sensors are installed at the mid-span section of the main beam with a sampling rate of 1000Hz; Braking temperature field: Infrared thermal imager is used to photograph the friction plate, 1 frame every 200ms; All parameters are aligned and the time deviation is ≤1ms.

[0017] Based on any of the above technical solutions, the further optimization is that the structured data processing in step 3 specifically includes: (1) Wheel contact stress interpolation processing: adapting to line contact characteristics, the gantry crane wheel and the track are in line contact, resulting in uneven contact stress distribution. A bilinear interpolation algorithm is adopted, and the discrete stress value based on the array sensor is processed by formula. ;in For orbital coordinates, All are bilinear interpolation fitting coefficients; calculate stress at any point, the interpolation range covers the contact width of 50mm, and the error is ≤5%; focus on extracting the maximum contact stress value of the stress concentration area at the wheel step, and calculate the ratio of the maximum contact stress to the material fatigue limit to provide a basis for subsequent judgment; (2) Track impact acceleration filtering: adapt to the impact transmission characteristics of the gantry crane, the gantry crane generates a high frequency impact of 200-500Hz when passing through the depression, and adopts a 500Hz Butterworth 10th order low-pass filter with attenuation ≥40dB / ten times the frequency; after filtering, calculate the impact peak and duration to ensure that the peak deviation is ≤3%; (3) Main beam torsional deformation angle smoothing: adapt to the small deformation characteristics of the box-type main beam, the gantry crane box-type main beam has a large torsional stiffness, resulting in small torsional deformation, and adopts a 5-point sliding average filter, the window size balances noise reduction and response speed, and eliminates instantaneous interference such as wind blowing; after processing, according to the formula Calculate the torsional deformation angle; where, For the diagonal displacement difference, L is the side length of the main beam section, and 3 decimal places are retained; (4) Analysis of the temperature field of the brake friction pad: To adapt to the characteristics of the large area friction pad, the large area of ​​the brake friction pad of the gantry crane leads to uneven temperature distribution. The infrared thermal imager software is used to draw isotherms and mark the area ratio of each temperature interval; when extracting the highest temperature, the high temperature point at the edge is excluded, and the highest value of the 70% area in the center is taken. At the same time, the temperature rise rate is calculated to provide a basis for the judgment of brake thermal decay; (5) Synchronous alignment of multiple data: To adapt to the coupling transmission requirements, the fault impact of the gantry crane is transmitted through multiple structures. Based on the synchronous trigger signal, the parameters are aligned according to the timestamp, and the deviation is ≤1ms; after alignment, the correlation is verified. If the deviation is >1ms, the data is collected again, and the original data and the processed data are stored at the same time to facilitate subsequent traceability.

[0018] Based on any of the above technical solutions, the further optimization is that the coupling determination in step 4 is as follows: (1) Parameter normalization processing: The mass of the gantry crane trolley of 50-500t has a significant impact on impact and braking. A trolley mass correction coefficient k is introduced. m Its calculation formula is (e.g., a 200t truck) Based on this coefficient, the eigenvalues ​​of each parameter are normalized: Normalized contact stress: Normalized peak impact: Normalized torsional deformation angle: Normalized temperature: (2) Coupled model construction: Using normalized parameters as input, a coupled decision model is constructed, and the safety factor is calculated. ;in: ; (3) Dynamic threshold setting: The threshold is dynamically adjusted according to the working conditions of the gantry crane: Full load condition: S>1.2 unsafe, 1.0≤S≤1.2 critical, S<1.0 safe; Half load condition: S>1.3 unsafe, 1.1≤S≤1.3 critical, S<1.1 safe; When the gust exceeds 20m / s: the threshold is lowered by 0.1; (4) Judgment execution: Judgment is based on the priority of structural safety > braking safety > contact safety: If If it is directly judged as unsafe; If deemed unsafe; The safety is determined by combining the S value; if all parameters meet the standard and S < the threshold, it is considered safe.

[0019] Based on any of the above technical solutions, the further optimization is that the root cause tracing in step 4 includes: (1) Tracing the excessive wheel contact stress: If the contact stress exceeds the standard, observe the micro-morphology of the wheel tread using a scanning electron microscope: If the texture valley depth is <0.8mm, it is determined that the insufficient texture leads to stress concentration; if there is metal peeling on the tread, it is determined to be contact fatigue; at the same time, use a laser diameter gauge to detect the roundness of the wheel, if the roundness is >0.1mm, it is determined to be out of roundness of the wheel; (2) Tracing the excessive main beam torsional deformation: If the torsional deformation exceeds the standard, use stress wave tomography to detect the inside of the main beam: If a defect ≥1mm is found, it is determined to be welding defect leading to insufficient stiffness; if there is no defect, detect the track settlement gradient, if it is >0.5mm / m, it is determined to be track unevenness leading to unilateral stress; at the same time, check the outrigger fastening bolts. (3) Braking temperature exceeds standard: If the braking temperature exceeds standard, disassemble the braking device for inspection: Use a feeler gauge to measure the brake shoe clearance. If the difference between the two sides is >0.2mm, it is determined that the uneven wear caused local overheating; Use a hardness tester to measure the hardness of the friction pad. If HRC <25, it is determined that the friction pad material is deteriorated; Check the brake cylinder oil pressure. If the oil pressure is insufficient, it is determined that the braking thrust is insufficient, resulting in sliding friction; (4) Impact acceleration exceeds standard: If the impact acceleration exceeds standard, check the track depression: Use a track ruler to measure the depression depth. If it is >2mm, it is determined that the depression is too deep; If the depression depth is normal, check the wheel tread step. If the step is >3mm, it is determined that the step caused the impact; At the same time, check the trolley suspension system. If the spring stiffness is insufficient, it is determined that the suspension failure amplified the impact.

[0020] Based on any of the above technical solutions, the further optimization is that the targeted rectification in step 6 includes: (1) Wheel tread texture repair: If the texture is insufficient, laser cladding technology is used, iron-based alloy powder is selected, the powder feeding amount is 10g / min, the protective gas is argon, the cladding layer thickness is 0.5-1mm, and the processed texture is net-like; after cladding, the texture is detected by line laser scanning to ensure that the valley depth meets the standard, and at the same time, the hardness of the cladding layer is measured by hardness tester to be HRC≥30 and the bonding strength ≥300MPa; (2) Track depression repair: If the track is depressed, arc welding is used to fill it, the welding current is 100-120A, the welding speed is 5mm / s, and after filling, the track top surface is ground with an angle grinder until the flatness is ≤0.1mm.

[0021] After grinding, use an ultrasonic thickness gauge to check the track thickness to ensure there is no false welding. At the same time, use a track ruler to check the height difference between the repair area and the surrounding track ≤0.05mm; (3) Repair of main beam weld defects: If the main beam has welding defects, use repair welding, open a V-shaped groove, weld current 120-150A, interpass temperature ≤250℃, and after repair welding, perform vibration aging to eliminate residual stress ≤150MPa; after aging, use an ultrasonic flaw detector to check to ensure the defects are eliminated, and at the same time measure the torsional deformation angle of the main beam to ensure ≤0.1° / m; (4) Repair of brake wear: If the brake wears unevenly, grind the brake shoes, adjust the difference between the two sides of the brake shoe gap ≤0.2mm, and after grinding, check the contact area of ​​the brake shoes ≥80%.

[0022] If the friction pads are not hard enough, replace them. After replacement, run them under no-load for 5 times and check that the braking temperature is ≤200℃ and the braking time is 0.5±0.05s.

[0023] Based on any of the above technical solutions, a further optimization is to add a wheel-track contact state calibration sub-step in the multi-dimensional static calibration of step 1. This step is located after the track settlement gradient measurement and specifically includes: using a 3D laser scanner to collect wheel contact patch images every 5m along the entire track when the trolley is unloaded; measuring the ratio of the contact patch area to the wheel tread width, requiring the ratio to be ≥0.65; measuring the lateral offset of the contact patch geometric center relative to the wheel centerline, requiring the offset to be ≤5mm; if the above two indicators do not meet the requirements, correction is made through the horizontal guide wheel adjustment device of the trolley traveling mechanism (adjustment accuracy ±0.1mm), and data is re-collected after each adjustment until both indicators meet the requirements.

[0024] Based on any of the above technical solutions, a further optimization is to add a multi-condition timing control sub-step in the fault coupling simulation of step 2, located after the fault parameter setting. Specifically, it includes: using a PLC timing controller to trigger the fault in the following order: starting the trolley to travel to the rated speed; triggering a local track depression after 2 seconds; synchronously triggering wheel tread step and instantaneous gust of wind at 3 seconds; triggering brake wear and performing emergency braking at 4 seconds; during the fault simulation process, applying a dynamic load to the mid-span of the main beam through the existing electro-hydraulic servo loading system, with the load waveform set according to the actual applicable working conditions; and controlling the 24 sensor data of the main beam, outriggers, and track to be synchronously fed back to the control center in real time.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. This invention addresses the structural and operational conditions of gantry cranes, including unidirectional trolley travel, rigid welding of main beam and outriggers, long track bearing, dual-side braking, and open-air operation. It designs a full-process solution encompassing multi-dimensional static calibration (including parameters such as wheel texture and weld stress), fault coupling simulation (including faults such as wheel steps and track indentations), and targeted rectification (including adaptation processes such as laser cladding repair of wheel texture).

[0027] It overcomes the limitations of existing general-purpose crane testing technologies in terms of their insufficient adaptability to the integrated structure of gantry cranes, and solves the problem of test distortion caused by neglecting equipment attributes in traditional methods.

[0028] 2. In the data acquisition and processing stage, parameters are collected synchronously using high-precision equipment such as arrayed piezoelectric sensors and laser displacement sensors. The data is then processed using adaptive algorithms such as bilinear interpolation and 10th-order low-pass filtering to ensure the accuracy of measurement and calculation of core parameters such as contact stress and torsional deformation angle. In the coupling judgment stage, a large vehicle mass correction coefficient and dynamic threshold are introduced to construct a multi-parameter coupling model. The model prioritizes structural safety > braking safety > contact safety. Compared with the traditional coarse judgment standard, the false judgment rate of unsafe conditions is reduced, and accurate identification of risks at all levels, from microscopic defects to macroscopic structures, is achieved.

[0029] 3. The root cause tracing process adopts a combination of microscopic morphology observation, macroscopic geometric detection, and system correlation verification. For parameters exceeding the standard such as contact stress and torsional deformation, it accurately locates the root causes such as insufficient texture, welding defects, and brake wear, and distinguishes between microscopic, macroscopic, and direct-indirect influencing factors. The targeted rectification process matches processes such as laser cladding and arc welding filling, which reduces maintenance costs compared to the traditional overall replacement solution.

[0030] At the same time, core parameters are retested after rectification to form a closed-loop management system, ensuring that risks are completely eliminated and significantly improving equipment maintenance efficiency and reliability.

[0031] 4. The fault coupling simulation stage realizes the reproduction of multiple fault couplings such as wheel steps, track indentation, brake wear and instantaneous gusts. The PLC timing control restores the real fault chain of start-up-obstacle-compound fault-emergency braking. The dynamic threshold setting is adjusted differently for different working conditions such as full load, half load and gusts. Under severe conditions such as extreme wind load, the threshold is lowered in advance to warn of risks.

[0032] Compared to traditional single-fault testing, it can capture hidden coupled risks (such as track indentation + main beam resonance caused by gusts of wind), shorten the safety verification cycle of the entire equipment life cycle, and provide strong support for operational safety under complex conditions such as outdoor heavy loads. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0034] In all the accompanying drawings, similar elements or parts are generally identified by similar reference numerals.

[0035] In the accompanying drawings, the components or parts are not necessarily drawn to actual scale.

[0036] Figure 1 This is a flowchart of the process of the present invention. Detailed Implementation

[0037] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0038] The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only examples, and should not be used to limit the scope of protection of the present invention. The specific process of the present invention is as follows: Figure 1 As shown in the image.

[0039] A method for testing the dynamic operation safety of a crane includes: Step 1, multi-dimensional static calibration: collecting micro-texture of wheel tread (valley depth ≥ 0.8 mm), residual stress of main beam-outer leg weld (≤ 150 MPa), track foundation settlement gradient (≤ 0.5 mm / m), environmental temperature and humidity correction coefficient (deviation ≤ 2%), and trolley brake shoe clearance (difference between the two sides ≤ 0.2 mm). If all parameters meet the standards, proceed to the next step.

[0040] This step involves systematically collecting and threshold-checking key structural parameters, connection status, basic conditions, and environmental influencing factors of the equipment to construct a reference coordinate system for dynamic testing.

[0041] It can be specifically adapted to structural characteristics: precisely targeting the structure of gantry cranes with unidirectional trolley travel, rigid welding, long track bearing, open-air operation, and dual-side braking, avoiding the limitations of general calibration methods. The calibration dimensions are highly matched with the risk points of the equipment structure. Quantitative thresholds ensure accuracy: each parameter has a clearly defined quantitative threshold (e.g., valley depth ≥ 0.8mm, residual stress ≤ 150MPa), and the thresholds are determined based on material performance tests (e.g., Q355B contact fatigue test), industry standards (e.g., GB / T3811-2008), and engineering experience, ensuring the verifiability and consistency of calibration results. Full parameter linkage verification: all parameters must meet the standards to proceed to the next step, avoiding the omission of risks from multiple parameters being superimposed even if a single parameter is qualified, forming a closed-loop benchmark control, laying the foundation for the accuracy of subsequent dynamic testing.

[0042] Step 2, Fault Coupling Simulation: Simulate local stepping on wheel tread (3mm deep), local depression in track (2mm deep), uneven wear of trolley brake (50% increase in clearance on one side), and instantaneous gust (20m / s for 5s). Simultaneously collect wheel contact stress distribution, track impact acceleration, main beam torsional deformation angle, and brake friction pad temperature field.

[0043] By combining physical simulation and environmental simulation, the scenario of multiple faults superimposed on the equipment under extreme operating conditions is reproduced.

[0044] Specifically, precision grinding machines are used to process wheel tread steps to simulate unidirectional walking wear, arc welding is used to create track indentations to simulate long-term load-bearing deformation, brake shoe clearance is adjusted to simulate bilateral braking wear, and wind tunnel equipment is used to simulate sudden gusts of wind in the open air. At the same time, for the force transmission path of wheel-track-main beam-brake, array sensors are deployed to synchronously collect four key physical quantities: contact stress distribution, impact acceleration, torsional deformation angle, and temperature field, to capture multi-dimensional response data after fault coupling.

[0045] Step 3, Structured Data Processing: The collected wheel contact stress distribution is processed using a bilinear interpolation algorithm to obtain complete stress data. The track impact acceleration is subjected to a 500Hz low-pass filter to extract impact features. The torsional deformation angle of the main beam is denoised by moving average to ensure the accuracy of deformation. The temperature field of the brake friction pad is analyzed by isotherm analysis to extract temperature parameters. After extracting the feature values ​​of the above four types of data, time alignment is performed based on the synchronous trigger signal to ensure that the alignment deviation is ≤1ms.

[0046] Based on the multi-source nature and noise characteristics of the collected data, this step designs differentiated processing algorithms for the essential characteristics of different physical quantities to achieve noise reduction, completion, and feature extraction of the original data.

[0047] Specifically, to address the discrete distribution characteristics of wheel contact stress, a bilinear interpolation algorithm is used to complete the stress at any point in the contact area, covering a 50mm contact width with a control error ≤5%; to address the 200-500Hz high-frequency noise of track impact acceleration, a 500Hz Butterworth 10th-order low-pass filter (attenuation ≥40dB / decimal) is used to extract the impact peak; to address the small-value characteristics of the main beam torsional deformation angle (<0.1°), a 5-point moving average filter is used to remove instantaneous interference, and the deformation is calculated using the arctangent formula; to address the uneven distribution of the braking temperature field, isotherm analysis is used to extract the highest temperature and heating rate in the central region; finally, the time alignment of the four types of data is completed based on the synchronous trigger signal to ensure the temporal correlation of the feature values.

[0048] Step 4, Coupling Determination: Construct a multi-parameter model, introduce a large vehicle mass correction coefficient, and determine that the superposition coefficient ≥ 1.2 is unsafe.

[0049] Multi-parameter quantification and fusion function: The four types of dispersed parameters, namely stress, acceleration, deformation and temperature, are integrated into a single safety factor S through the model, realizing the quantitative expression of multi-dimensional risks and facilitating intuitive assessment of the overall safety status of the equipment.

[0050] Operating condition adaptation judgment function: By dynamically adjusting the threshold, the safety status assessment of the same equipment under different loads and environments can be more accurate. For example, under gust conditions, the threshold can be lowered by 0.1 to provide early warning of safety risks caused by wind load superposition.

[0051] The graded risk management function divides the risk into three levels: unsafe (>1.2), critical (1.0-1.2), and safe (<1.0) based on the S value, and clarifies the priority judgment rules to provide targeted guidance for subsequent root cause tracing and rectification (such as directly identifying structural problems when torsional deformation exceeds the standard).

[0052] Step 5, root cause analysis: Scanning electron microscopy to observe the tread morphology, stress wave analysis to measure main beam defects, and brake gap detection to locate the microscopic and macroscopic root causes.

[0053] For the parameters exceeding the standard identified in the coupling judgment, targeted detection methods are used to locate the root causes of the fault at both the micro and macro levels.

[0054] Specifically, if the wheel contact stress exceeds the standard, the micro-morphology of the tread is observed using a scanning electron microscope (500x magnification) to identify insufficient texture (valley depth < 0.8mm) or metal spalling (contact fatigue), and the roundness is detected using a laser diameter gauge to identify wheel out-of-roundness; if the main beam torsional deformation exceeds the standard, internal defects ≥ 1mm are detected using stress wave tomography (frequency 2.5MHz) to identify welding problems, and uneven external stress is located by re-measuring the track settlement gradient and outrigger bolt torque; if the braking temperature exceeds the standard, the brake shoe clearance is measured using a feeler gauge, the friction plate hardness is measured using a hardness tester, and the cylinder oil pressure is measured using a pressure gauge to distinguish between uneven wear, material deterioration, or insufficient thrust; if the impact acceleration exceeds the standard, the indentation depth is measured using a track ruler, wheel step detection is performed, and the suspension system stiffness is checked to trace the excitation source.

[0055] Step 6, targeted rectification: laser cladding repairs wheel texture, arc welding fills track depressions, brake shoe grinding, and retests dual parameters after rectification.

[0056] This step, based on the results of root cause tracing, adopts appropriate repair processes for different fault types to achieve a closed-loop management of precise rectification and effect verification.

[0057] Specifically, if the root cause is insufficient wheel tread texture, laser cladding technology (500W fiber laser, iron-based alloy powder, powder feed rate 10g / min) is used to process a mesh texture, ensuring a valley depth of 0.8-1.0mm and a hardness of HRC≥30; if the root cause is track depression, arc welding is used to fill the depression (E5015 welding rod, current 100-120A) followed by grinding, ensuring flatness ≤0.1mm and height difference with the surrounding area ≤0.05mm; if the root cause is brake wear, a 120-grit abrasive wheel is used to grind the brake shoes and adjust the gap, ensuring a difference between the two sides ≤0.2mm and a contact area ≥80%. If the friction pad hardness is insufficient, replace it with a copper-based powder metallurgy friction pad. After rectification, the core parameters of the rectified parts (such as wheel valley depth, track flatness, and brake temperature) are retested to ensure compliance.

[0058] Based on any of the above technical solutions, the following optimization is made: (1) Micro-texture collection of wheel tread (adapted to unidirectional travel wear of gantry crane): The gantry crane travels unidirectionally along a fixed track for a long time. Uneven texture wear is likely to occur in the outer 1 / 3 area of ​​the tread. A line laser scanning device (accuracy ±0.01mm) is used to take one section every 15° along the circumference of the wheel. 50 data points (spacing ≤2mm) are collected radially (from wheel flange to center) of each section. The average depth of the texture valley (vertical distance from valley to peak) is calculated by software. The preset threshold is ≥0.8mm (based on the Q355B wheel contact fatigue test, if the texture is too shallow, the contact stress will exceed the fatigue limit of 350MPa).

[0059] If the valley depth is <0.8mm, it is marked as needing repair. The texture will be restored by laser texture processing (power 500W, scanning speed 100mm / s). After processing, the valley depth will be retested to ensure that it meets the standard. At the same time, the texture roughness Ra is tested to be ≤1.6μm (to avoid excessive roughness from aggravating track wear).

[0060] This step is based on the characteristic that the outer 1 / 3 area of ​​the tread is preferentially worn due to the unidirectional travel of the gantry crane trolley. High-precision line laser scanning is used to obtain micro-texture data of the tread surface, and the average valley depth is quantified by software analysis to evaluate the contact stress dispersion capability.

[0061] The depth of the texture valleys directly affects the wheel-rail contact area and stress distribution. Based on the Q355B wheel contact fatigue test data, a valley depth of ≥0.8mm is set as a safety threshold to avoid contact stress exceeding the 350MPa fatigue limit. For substandard textures, laser texture processing technology is used to regenerate a texture structure that meets the requirements by controlling the laser power and scanning speed, while controlling the roughness to balance wear resistance and track protection requirements.

[0062] (2) Collection of residual stress in the main beam-leg weld (for rigid welded structures): The main beam and the leg of the gantry crane are rigidly welded (unlike the hinged connection of the tower crane). The weld is prone to residual stress. Three points are arranged in the upper, middle and lower ranges within 20mm on both sides of the weld (covering the stress concentration area). The blind hole method (drilling diameter 1.5mm, depth 2mm) is used to calculate the residual stress. The preset threshold is ≤150MPa (Q355B yield limit 40%, with a safety margin reserved).

[0063] If the stress is >150MPa, vibration aging treatment should be performed (excitation frequency 20-50Hz, excitation force 5-10kN, lasting 20min). After treatment, the stress distribution uniformity should be improved by 30% (to avoid stress concentration during sudden stops of the trolley, which could lead to weld cracking). At the same time, use an ultrasonic flaw detector (frequency 2.5MHz) to inspect the inside of the weld to ensure that there are no defects ≥1mm.

[0064] This step targets the rigid welded structure of the main beam and legs of a gantry crane (as opposed to the hinged structure of a tower crane), focusing on the risk point of residual stress in the weld seam, and using the blind hole method for stress quantification detection.

[0065] The residual stress generated by thermal deformation and constraint release during welding is prone to superposition under dynamic loads such as sudden stops of large vehicles, leading to weld cracking. Based on the yield strength (375MPa) of Q355B, a threshold of ≤150MPa (40% of the yield strength) is set to reserve sufficient safety margin. Vibration aging treatment is adopted for excessive stress. Through vibration energy input with specific frequency and excitation force, stress redistribution is promoted. At the same time, ultrasonic testing is used to eliminate internal defects, realizing dual control of stress and defects.

[0066] (3) Track foundation settlement gradient acquisition (adapted to continuous track bearing): The track of the gantry crane is 10-50m long. Uneven foundation settlement can easily lead to wheel wear. A total station (accuracy ±2mm) is used to set an elevation point every 3m along the entire length of the track (including both ends, mid-span and frequently stopped positions of the gantry crane). The ratio of the settlement difference between adjacent points to the distance (settlement gradient) is calculated. The preset threshold is ≤0.5mm / m (compliant with GB / T3811-2008 track installation accuracy).

[0067] If the gradient is greater than 0.5 mm / m, use epoxy resin grout (compressive strength ≥ 60 MPa) to lift it. Pause for 30 seconds after every 0.5 mm lift (wait for the foundation to stabilize). After the gradient is retested and meets the standard, use a track ruler (accuracy ± 0.01 mm) to check that the flatness of the top surface of the track is ≤ 0.1 mm (to avoid local bulges that may cause impact).

[0068] This step addresses the continuous load-bearing characteristics of gantry crane tracks (10-50m), focusing on the risk of wheel wear caused by uneven foundation settlement. A quantitative assessment is achieved by measuring elevation points with a total station and calculating the settlement gradient.

[0069] Differential settlement of the track foundation can cause linear or nonlinear deformation of the track, leading to poor contact between the wheels and the track, and unilateral stress causing rail wear. According to the GB / T3811-2008 track installation accuracy standard, a settlement gradient of ≤0.5mm / m is set as a safe threshold. For areas exceeding the standard, high-strength epoxy resin grouting material is used to lift the track. The foundation disturbance is avoided by lifting the track in small increments and pausing to stabilize it. After lifting, the flatness is controlled simultaneously to ensure that the track bearing surface meets the requirements of dynamic operation.

[0070] (4) Collection of environmental temperature and humidity correction coefficient (suitable for outdoor operation): Gantry cranes are mostly operated outdoors. Temperature and humidity affect the elastic modulus of steel. Environmental parameters are collected by temperature and humidity sensors (-10~40℃, 30%~80%RH). The correction table of GB / T19879-2005 is consulted to calculate the correction coefficient (e.g., 1.0 for 20℃ / 50%RH, 1.02 for -10℃). The preset deviation is ≤2% (to avoid strength calculation error).

[0071] If the deviation is greater than 2%, adjust the material parameters in the subsequent judgment (e.g., change the elastic modulus from 206 GPa to 208 GPa), and record the correction process to ensure traceability.

[0072] This step addresses the environmental characteristics of gantry cranes operating outdoors, focusing on the impact of temperature and humidity on the physical properties of steel (primarily the elastic modulus). By collecting environmental parameters through sensors and calculating correction coefficients, dynamic compensation of material parameters is achieved.

[0073] The elastic modulus of steel increases with decreasing temperature and fluctuates slightly with changes in humidity, directly affecting the accuracy of stress calculation. Based on the correction table in GB / T19879-2005 "Test Methods for Mechanical Properties of Steel", the real-time temperature and humidity parameters are converted into correction coefficients, and a correction deviation of ≤2% is set as the control threshold. For deviations exceeding the standard, the material parameters in the subsequent judgment are adjusted to ensure the accuracy of the mechanical calculation results.

[0074] (5) Collection of brake shoe clearance of gantry crane (adapted to double-sided braking structure): The gantry crane gantry is braked with double-sided brake shoes. Uneven clearance is prone to uneven wear. Use feeler gauge (accuracy ±0.01mm) to measure the clearance at 3 points at both ends and the middle of the brake shoe, calculate the difference in clearance between the two sides of the brake shoe, and preset the threshold ≤0.2mm (to avoid excessive braking load on one side).

[0075] If the difference is greater than 0.2mm, adjust the brake push rod stroke (retest once for every 0.1mm adjustment) to ensure that the clearance difference meets the standard, and at the same time check that the brake shoe contact area is ≥80% (to ensure braking efficiency).

[0076] This step addresses the structural characteristics of the double-sided brake shoes of the gantry crane, focusing on the risks of uneven wear and brake imbalance caused by uneven clearance. It achieves quantitative control by measuring the clearance at multiple points and calculating the difference between the two sides.

[0077] Uneven gap between the two brake shoes can lead to excessive force on one side during braking, causing uneven wear of the brake shoes, brake deviation, and even brake fade. Setting the gap difference between the two sides to ≤0.2mm as a safety threshold can ensure even distribution of braking load. The gap deviation can be corrected by adjusting the brake push rod stroke (small adjustments multiple times), while the brake shoe contact area is detected to ensure braking efficiency, forming a dual braking performance control of gap and contact area.

[0078] Based on any of the above technical solutions, the further optimization is that the specific fault coupling simulation in step 2 includes: (1) Local step simulation of wheel tread (adapted to unidirectional wear of the gantry crane): the unidirectional movement of the gantry crane tread causes steps to easily appear on the outer side of the tread. A precision grinding machine (accuracy ±0.01mm) is used to grind a 3mm deep and 50mm wide step in the outer 1 / 3 area (stress concentration area) of the wheel tread. The step transition radius is ≤1mm (simulating the smooth transition of actual wear). After grinding, a surface roughness meter (±0.01μm) is used to check to ensure that the surface Ra of the step is ≤3.2μm (close to the wear state on site).

[0079] At the same time, the diameter of the wheel is measured with a laser diameter gauge (±0.001mm) to ensure that the diameter deviation at the step is ≤0.1mm (to avoid distortion of the simulated fault).

[0080] This step is based on the actual working condition of a gantry crane's trolley traveling in one direction for a long time, which causes the outer 1 / 3 of the tread surface to wear out preferentially, forming a step. This typical fault is reproduced through precision machining.

[0081] Using a precision grinding machine with an accuracy of ±0.01mm, a 3mm deep and 50mm wide stepped structure was directionally machined in the outer 1 / 3 area where the wheel's stress is concentrated. By controlling the transition radius to ≤1mm, the natural smoothness of on-site wear was simulated. After grinding, the surface roughness (Ra≤3.2μm) and diameter deviation (≤0.1mm) were controlled by a surface roughness meter and a laser diameter gauge, respectively, to ensure that the simulated step closely resembled the real wear part in terms of shape, dimensional accuracy, and surface condition, thus providing a real fault excitation source for subsequent dynamic response testing.

[0082] (2) Simulation of local track depression (adapting to long track load deformation): Gantry crane tracks are prone to local depressions due to long-term load. At the mid-span of the track (where the trolley stops frequently), a 2mm deep and 100mm long groove is welded using arc welding (the depression depth is based on on-site data). After welding, the edge of the groove is ground with an angle grinder, and the transition radius is ≤0.5mm (to avoid impact caused by sharp edges). After grinding, the flatness of the depression area is checked with a track ruler (±0.01mm) and is ≤0.2mm. At the same time, the track thickness is checked with an ultrasonic thickness gauge (±0.01mm) to ensure that the depression does not cause the thickness to exceed the standard (to avoid simulating fault damage to the track).

[0083] This step addresses the practical characteristics of gantry cranes, specifically the tendency for localized dents to appear in areas with long-term load-bearing and frequent trolley stops along their 10-50m long tracks. It employs a welding-filling-grinding process to reproduce the fault.

[0084] A high-incidence depression location, the mid-span of the track where large vehicles frequently stop, was selected. A groove 2mm deep and 100mm long was formed by arc welding to simulate a depression. After welding, the edges were ground down to a transition radius of ≤0.5mm to avoid sharp edges causing unrealistic impacts. The flatness of the depression area was checked to ≤0.2mm using a track gauge to ensure that the depression shape closely resembled the deformation state on site. At the same time, an ultrasonic thickness gauge was used to verify the track thickness to avoid insufficient effective load-bearing thickness due to welding, thus ensuring the structural safety of the track itself during the test.

[0085] (3) Simulation of uneven wear of gantry crane brake (adapted to dual-side braking structure): The brake shoes of the gantry crane are prone to uneven wear due to uneven wear. Adjust the gap between the brake shoe on one side and the wheel to 1.5 times the design value (the design gap is 0.5-1mm, and the gap increases after simulating uneven wear). Use a feeler gauge to measure the gap on both sides to ensure that the gap on one side is more than 50% larger than the other side (e.g., 1.5mm on the left side and 1.0mm on the right side). At the same time, check that the contact area of ​​the brake shoe on the side with uneven wear is ≤70% (simulating the actual uneven wear state) to avoid the simulation distortion of brake failure due to the small contact area.

[0086] This step addresses the issue of uneven wear in the brake shoe braking structure of gantry cranes, which is prone to cause eccentric wear due to uneven wear. By adjusting the brake shoe clearance, this fault can be accurately simulated.

[0087] Based on the fault mechanism of increased clearance on one side due to uneven wear of brake shoes on both sides, the clearance between the brake shoe on one side and the wheel is adjusted to 1.5 times the design value (0.5-1mm). The clearance on one side is measured with a feeler gauge to ensure that it is more than 50% larger than the other side, thus reproducing the uneven clearance state. At the same time, the contact area of ​​the brake shoe on the unevenly worn side is checked to be ≤70%, simulating the characteristics of poor contact between the brake shoe and the wheel after actual uneven wear. This avoids complete brake failure due to insufficient contact area, ensuring that the simulated fault is both close to reality and can trigger an effective test response.

[0088] (4) Simulation of instantaneous gusts (adapted to sudden wind conditions in open-air operations): Gantry cranes are prone to instantaneous gusts in open-air operations. A wind tunnel device (maximum wind speed 30m / s) is used to control the wind speed to quickly increase from the ambient wind speed to 20m / s (common gust wind speed in ports) through PLC control. After 5 seconds, the wind speed returns to the ambient wind speed. The wind speed control accuracy is ±0.5m / s.

[0089] Simultaneously, a three-dimensional anemometer (±0.1m / s) is used to monitor the top, middle and bottom of the main beam to ensure that the uniformity deviation of gusts in the height direction of the main beam is ≤5% (the main beam of the gantry crane is tall, and uneven wind speed has a great impact), so as to avoid test errors caused by uneven wind speed.

[0090] This step addresses the environmental characteristics of gantry cranes operating outdoors, which are prone to sudden gusts of wind. It uses wind tunnel equipment and automated control technology to reproduce real gust conditions.

[0091] The wind tunnel equipment was deployed according to the GB / T36018-2018 standard to ensure that the air outlet was directly opposite the main beam and covered the entire windward surface. The wind speed was controlled in a closed loop by a variable frequency speed control system and a PLC. The gust parameters were set according to the JT / T604-2019 standard (rising to 20 m / s in 0.6-0.8 s and lasting for 5 s). The wind speed rise rate was controlled by a PID algorithm (P=2.5, I=0.8s, D=0.2s) to avoid overshoot. The wind speed in the upper direction of the main beam was monitored by a three-dimensional anemometer, and the guide grid was adjusted to ensure that the uniformity deviation was ≤5%. Finally, the sudden gust environment common in ports was reproduced, providing real excitation for testing the wind load response of the equipment.

[0092] It needs to be explained that the deployment specifications for wind tunnel equipment are as follows: According to Article 5.3 of GB / T36018-2018 "Wind Tunnel Test Method for Cranes", the wind tunnel outlet should be arranged at 0° directly opposite the main beam of the gantry crane, the center height of the outlet should be the same as the midpoint height of the main beam, and the horizontal distance should be 1.2-1.5 times the height of the main beam (e.g., if the main beam is 10m high, the distance should be 12-15m). The cross-sectional area of ​​the outlet should be ≥ 2 times the windward cross-sectional area of ​​the main beam (to ensure that the airflow completely covers the structure).

[0093] The wind tunnel fan adopts a variable frequency speed control system (speed range 0-50Hz) and communicates with the PLC via Modbus-RTU protocol to achieve closed-loop control of wind speed.

[0094] Method for adjusting wind speed uniformity: When the three-dimensional anemometer detects a uniformity deviation of >5%, it is corrected by adjusting the angle of the wind tunnel outlet guide grid (adjustment accuracy ±1°) - when the top wind speed is low, the top grid angle is increased, and when the bottom wind speed is low, the bottom grid angle is decreased. After each adjustment, wait for 3 seconds and then monitor again until the deviation meets the standard.

[0095] This adjustment method complies with the uniformity control requirements for environmental simulation in ISO 12100-2010 "Basic concepts and design principles for safety of machinery".

[0096] Control parameters for gust rise rate: The rise time from ambient wind speed to 20 m / s is set to 0.6-0.8 s (simulating the sudden change characteristics of natural gusts, referring to the gust parameters in Appendix C of JT / T604-2019 "Safety Regulations for Port Cranes"). The PLC controls the frequency change rate of the fan through a PID algorithm, with a proportional coefficient P=2.5, integral time I=0.8 s, and derivative time D=0.2 s, ensuring no overshoot during the wind speed rise process and that the deviation between the actual rate and the target rate is ≤10%.

[0097] (5) Multi-parameter synchronous acquisition (adapting to multi-structure coupling): For the coupling characteristics of gantry crane wheels-track-main beam-brake, synchronous acquisition is performed as follows: Contact stress: Array piezoelectric sensors (0-20MPa, 0.1%FS) are laid along the track with a spacing of ≤5mm and a sampling rate of 10000Hz (capturing instantaneous stress); Impact acceleration: Acceleration sensors (0-500m / s², ±0.5%FS) are installed 100mm on both sides of the depression with a sampling rate of 10000Hz; Torsional deformation angle: 4 laser displacement sensors (±0.01mm) are installed at the mid-span section of the main beam with a sampling rate of 1000Hz; Braking temperature field: Infrared thermal imager (640×512, -20~600℃) takes pictures of the friction pad, with 1 frame every 200ms. All parameters are aligned through a synchronous triggering device (±0.1ms), with a time deviation of ≤1ms (ensuring the accuracy of coupling analysis).

[0098] This step addresses the multi-structural coupling characteristics of gantry cranes, including wheels, rails, main beams, and brakes, by employing multiple types of high-precision sensors and synchronous triggering technology to achieve collaborative acquisition of key parameters across components.

[0099] Sensors are deployed around the force transmission path—an array of piezoelectric sensors is laid on the track to capture contact stress, accelerometers are installed on both sides of the depression to collect impact signals, laser displacement sensors are arranged at the mid-span of the main beam to measure torsional deformation, and infrared thermal imagers capture the temperature field of the brake friction pads; the sampling rate is matched according to the dynamic characteristics of the parameters; all parameters are aligned by a synchronous triggering device with an accuracy of ±0.1ms, and the time deviation is controlled to ≤1ms to ensure that the collected data are synchronized in the time dimension, providing a spatiotemporally consistent multi-source data foundation for subsequent coupled analysis.

[0100] Based on any of the above technical solutions, the further optimization is that the structured data processing in step 3 specifically includes: (1) Wheel contact stress interpolation processing: adapting to line contact characteristics, the gantry crane wheel and the track are in line contact, resulting in uneven contact stress distribution. A bilinear interpolation algorithm is adopted, and the discrete stress value based on the array sensor is processed by formula. ;in For orbital coordinates, All are bilinear interpolation fitting coefficients) to calculate the stress at any point, with the interpolation range covering a contact width of 50mm and an error ≤5% (calibrated with a standard pressure block); Based on common knowledge and industry standards in the field of the art, it is necessary to explain the following: Arrangement parameters of the sensor array: Array-type piezoelectric sensors (preferably model PX210, conforming to IEC61298-2 standard) are arranged one every 5mm along the length of the track and three columns along the width of the track (corresponding to the inner 1 / 3, middle, and outer 1 / 3 areas of the wheel tread, respectively). The flatness between the top surface of the sensor and the top surface of the track is ≤0.02mm (detected with a dial indicator), and they are fixed by epoxy resin bonding with a curing time ≥24 hours.

[0101] The arrangement density meets the sampling requirements for wheel-rail contact stress testing in JB / T10782-2007 "Crane Wheels" and can cover the entire contact area.

[0102] The process of solving for interpolation coefficients: The solution is obtained by fitting using the least squares method. The specific steps are as follows: ① Collect the discrete stress values ​​of the array sensor. and corresponding coordinates (i≥30, ensuring sufficient sample size); ②Establish the objective function ③ Use the lsqcurvefit function in MATLAB software to solve the problem. The goodness of fit R² should be ≥0.95 (meeting the requirements for fitting accuracy in GB / T27418-2017 "Evaluation and Expression of Measurement Uncertainty"); ④ Output coefficients And store it in the test system.

[0103] Standard pressure block calibration procedure: Use a third-class standard pressure block (accuracy ±0.1MPa, traceable to the national pressure standard), apply pressures of 5MPa, 10MPa, and 20MPa at five points (four corners and center) of the sensor array, respectively, and record the interpolated values ​​after holding each pressure level for 3 seconds.

[0104] Calculate relative error If the error at any measuring point E > 5%, the sensor spacing needs to be reduced to 3mm, the sensors rearranged, and the coefficients fitted until the error at all measuring points meets the standard.

[0105] The maximum contact stress value (easily exceeding 20MPa) of the stress concentration area at the wheel step is extracted. At the same time, the ratio of the maximum contact stress to the material fatigue limit (350MPa) is calculated to provide a basis for subsequent judgment. (2) Track impact acceleration filtering: Adapt to the impact transmission characteristics of the gantry crane. When the gantry crane passes through the depression, it generates a high frequency impact of 200-500Hz. A 500Hz Butterworth 10th order low-pass filter is used, with an attenuation of ≥40dB / tenth frequency (filtering out environmental noise).

[0106] After filtering, calculate the peak value (maximum value) and duration (from the start of the impact to the steady state), ensuring that the peak value deviation is ≤3% (compare before and after filtering).

[0107] This step is based on the transmission characteristics of the 200-500Hz high-frequency impact generated when the gantry crane trolley passes through the track depression. To purify the original impact acceleration signal, which is mixed with environmental noise (such as equipment operation vibration, electromagnetic interference, etc.), a 500Hz Butterworth 10th-order low-pass filter algorithm is used.

[0108] By utilizing the frequency selectivity of low-pass filtering, noise signals above 500Hz are attenuated (attenuation amplitude ≥40dB / decade), retaining effective impulse signals in the 200-500Hz range. After filtering, the impulse peak value (maximum signal value) and duration (time from the initial impulse signal jump to the recovery to steady state) are extracted. By comparing with the original signal before filtering, the peak deviation is controlled to ≤3%, ensuring that the effective impulse characteristics are not distorted due to filtering, and providing accurate impulse parameters for subsequent coupling determination.

[0109] (3) Smoothing of the torsional deformation angle of the main beam: To adapt to the small deformation characteristics of the box girder, the large torsional stiffness of the box girder of the gantry crane results in small torsional deformation (usually <0.1°). A 5-point moving average filter is adopted, and the window size is balanced with noise reduction and response speed to eliminate instantaneous interference such as wind. After processing, the angle is adjusted according to the formula. ;(in, Calculate the torsional deformation angle (L is the side length of the main beam section) for the difference in diagonal displacement, and retain 3 decimal places (to ensure accuracy).

[0110] This step takes into account the characteristics of the gantry crane's box-type main beam having high torsional stiffness and small torsional deformation (usually <0.1°), as well as the instantaneous interference such as wind blowing and vibration mixed in the original displacement signal, and adopts a 5-point moving average filter for signal smoothing.

[0111] By utilizing the time-domain averaging characteristics of moving average, the raw diagonal displacement data of the main beam collected by the laser displacement sensor is weighted and averaged using 5 consecutive sampling points as a window. While eliminating instantaneous interference, the noise reduction effect and signal response speed are balanced by optimizing the window size (5 points), avoiding excessive filtering that causes deformation signal lag. The deformation angle is calculated after filtering and three decimal places are retained to match the accuracy requirements of small deformations, providing accurate parameters for structural safety assessment.

[0112] (4) Temperature field analysis of brake friction pads: To adapt to the characteristics of large-area friction pads, the large area of ​​the brake friction pads of the gantry crane (>0.1㎡) leads to uneven temperature distribution. Infrared thermal imager software is used to obtain isotherms (interval of 10℃), and the area ratio of each temperature range is marked (e.g., area ratio of >200℃).

[0113] When extracting the highest temperature, exclude the high-temperature points at the edge (which dissipate heat quickly) and take the highest value of the central 70% area (which dissipates heat slowly and is most prone to thermal decay). At the same time, calculate the temperature rise rate (°C / s) to provide a basis for judging brake thermal decay (excessive temperature rise can easily lead to a decrease in the friction coefficient).

[0114] This step addresses the characteristics of gantry crane brake friction pads, which have a large area and uneven temperature distribution, by performing a refined analysis based on temperature field data collected by an infrared thermal imager.

[0115] The rate of temperature rise (the difference between the highest temperature and the initial temperature divided by the braking duration) is calculated to quantify the speed of temperature change and provide a multi-dimensional basis for assessing the risk of thermal fade in the braking system.

[0116] (5) Multi-data synchronization alignment: Adapt to the coupling transmission requirements, the impact of gantry crane failure is transmitted through multiple structures (time < 20ms). Based on the synchronous trigger signal, each parameter is aligned according to the timestamp, with a deviation ≤ 1ms.

[0117] After alignment, verify the correlation (e.g., the impact peak and deformation peak should appear simultaneously). If the deviation is >1ms, re-acquire the data (to avoid errors in coupling analysis). At the same time, store the original data and the processed data for subsequent traceability.

[0118] This step addresses the coupling characteristics of the rapid transmission (time < 20ms) of the impact of gantry crane faults among multiple structures such as wheels, rails, main beams, and brakes, and achieves time alignment of multi-source parameters based on synchronous triggering technology.

[0119] It needs to be explained that the quantitative rules for determining the S-value are as follows: Based on the risk assessment requirements of Article 6.3 of GB / T3811-2008 "Code for Design of Cranes", when... When this occurs, it needs to be judged from two dimensions: the extent of exceeding the standard and the S value. If the extent of exceeding the standard is ≤10% (i.e., ... If S < the corresponding operating condition threshold, it is judged as a critical state; if the exceedance is >10%, it is judged as unsafe regardless of whether the S value is lower than the threshold.

[0120] The extent of exceeding the standard can be assessed using the quantitative evaluation method of ISO 13849-1 "Safety-related components of mechanical safety control systems".

[0121] The actual weight of the trolley is obtained as follows: The actual weight is the sum of the trolley's curb weight and the current lifting load. The curb weight can be directly taken from the value marked on the equipment's nameplate (error ≤2%). The lifting load is collected in real time by the lifting capacity limiter (compliant with GB / T22427.1-2008 standard, accuracy ±1%). The two are then automatically added together and substituted into the final weight. The calculation formula requires no human intervention, ensuring the accuracy and reproducibility of the data acquisition.

[0122] Time window definition for eigenvalue extraction: contact stress The characteristic values ​​of impact acceleration a, torsional deformation angle θ, and temperature T are all extracted from the critical period of fault coupling simulation—from the triggering of track indentation (2 seconds) to the end of emergency braking (1 second steady state period after 4 seconds). This window covers the peak response stage of multiple fault superposition, which meets the time definition requirements for dynamic parameter acquisition in JB / T10559-2006 "Crane Test Specifications and Procedures", and can avoid judgment deviation caused by arbitrary window selection.

[0123] It should be noted that: a structured processing flow was designed to address the data characteristics of gantry cranes, including line contact, high-frequency impact, small deformation, large-area friction plates, and coupled transmission; bilinear interpolation was used to generate complete stress field data; 10th-order filtering was used to retain impact peak values; moving average was used to adapt to small deformations, addressing the issue of large boom vibrations; isotherms were used to mark temperature distribution; and high-precision alignment ensured coupled analysis; this approach can effectively handle small deformation, high frequency, and unevenly distributed data from gantry cranes, with improved processing accuracy compared to existing technologies.

[0124] Based on any of the above technical solutions, the further optimization is that the coupling determination in step 4 is as follows: (1) Parameter normalization processing: The mass of the gantry crane trolley of 50-500t has a significant impact on impact and braking, so a trolley mass correction coefficient is introduced. Its calculation formula is (e.g., a 200t truck) Based on this coefficient, the eigenvalues ​​of each parameter are normalized: Normalized contact stress: (Higher mass leads to increased contact stress); Normalized peak impact value: (Large mass, large impact inertia); Normalized torsional deformation angle: (Large mass leads to large main beam deformation); Normalized temperature: (Large mass results in heavy braking load and high temperature).

[0125] This step addresses the characteristics of gantry cranes, such as a large range of trolley mass (50-500t) and the significant impact of mass on response to impact and braking, by introducing a mass correction coefficient to achieve normalization calibration of multiple parameters.

[0126] Using 100t as a benchmark, the actual mass of the vehicle is converted into a dimensionless coefficient (actual mass / 100t). Based on the physical law that the greater the mass, the more significant the impact on the response parameters, linear amplification correction is applied to the contact stress, impact peak, and torsional deformation angle, while nonlinear amplification correction is applied to the braking temperature (adapting to the nonlinear relationship between braking load and temperature). Finally, the parameter characteristic values ​​of equipment with different masses are unified to the same benchmark, eliminating the interference of mass differences on subsequent coupling judgment.

[0127] (2) Coupled Model Construction: Using normalized parameters as input, a coupled decision model is constructed, and the safety factor is calculated. ;in: (Q355B contact fatigue limit); (GB / T3811-2008 Permissible Impact Values); (Allowable torsion angle of box girder); (Heat resistance limit of friction plate).

[0128] This step is based on the coupled characteristics of multiple parameters affecting equipment safety, and uses normalized parameters as input to construct a weighted summation safety factor calculation model.

[0129] The normalized contact stress, peak impact, torsional deformation angle, and temperature are compared with their respective limit values ​​to obtain the relative risk coefficients (dimensionless) of each parameter. The comprehensive safety factor S is obtained by weighted summation based on the influence weight of each parameter on safety, which quantitatively reflects the overall safety status of the equipment under the coupling effect of multiple parameters.

[0130] All limit values ​​are derived from existing material performance tests or industry standards (such as GB / T3811-2008) to ensure the reliability of model input.

[0131] (3) Dynamic threshold setting: The threshold is dynamically adjusted according to the working conditions of the gantry crane: Full load condition (100% rated load): S>1.2 is unsafe, 1.0≤S≤1.2 is critical, S<1.0 is safe; Half load condition (50% rated load): S>1.3 is unsafe, 1.1≤S≤1.3 is critical, S<1.1 is safe; When the gust exceeds 20m / s: the threshold is lowered by 0.1 (e.g., full load S≥1.1 is unsafe).

[0132] This step establishes a dynamic threshold adjustment mechanism based on the differences in the impact of gantry crane operating conditions (load status, environmental wind conditions) on safety risks.

[0133] The greater the load, the higher the load on the equipment structure and braking system, and the smaller the safety redundancy. Therefore, the threshold for full-load condition (100% rated load) is set lower than that for half-load condition (50% rated load) (e.g., the unsafe threshold for full load is 1.2 vs. 1.3 for half load). When the gust exceeds 20 m / s, the wind load will increase the additional stress on the structure and the difficulty of braking, further compressing the safety redundancy. Therefore, the threshold is lowered by 0.1 based on the original condition threshold (e.g., the full load threshold is reduced from 1.2 to 1.1). By dividing the three-level range of safe, critical and unsafe, accurate risk classification under different conditions can be achieved.

[0134] (4) Judgment Execution: Judgment is based on priority: structural safety > braking safety > contact safety. If... (If the torsional deformation of the main beam exceeds the standard, it is directly judged as unsafe (to avoid damage to the main beam); if (Brake temperature exceeds the limit), deemed unsafe (avoid heat fade); if The safety is determined by combining the S value; if all parameters meet the standard and S < the threshold, it is considered safe.

[0135] This step establishes a priority-based judgment and execution logic based on the principle of different safety risk consequences.

[0136] Prioritize safety according to the severity of the consequences: Structural safety (torsional deformation of the main beam) is related to the overall stability of the equipment. Failure can lead to fatal accidents such as main beam fracture, so it has the highest priority. Braking safety (brake temperature) is related to brake reliability. Failure can lead to runaway and collision, so it has the second highest priority. Contact safety (contact stress and impact acceleration) is related to the lifespan of components. Failure can lead to localized damage, so it has the lowest priority.

[0137] During execution, high-priority parameters are checked first: if the structure or braking fails, it is directly judged as unsafe; only when the high-priority parameters meet the standards are the contact safety parameters combined with the safety factor S value judged; finally, all parameters must meet the standards and S < the threshold before it can be judged as safe.

[0138] Based on any of the above technical solutions, the further optimization is that the root cause tracing in step 4 includes: (1) Tracing the excessive wheel contact stress (adapting to line contact characteristics): If the contact stress exceeds the standard, observe the micro-morphology of the wheel tread using a scanning electron microscope (magnification of 500 times): If the texture valley depth is <0.8mm, it is determined that the insufficient texture leads to stress concentration (for gantry cranes traveling in one direction); if there is metal peeling on the tread, it is determined to be contact fatigue (it is necessary to check whether the weld stress affects the wheel positioning); at the same time, use a laser diameter gauge to check the roundness of the wheel. If the roundness is >0.1mm, it is determined that the wheel is out of round (caused by long-term braking of the trolley).

[0139] This step addresses the issue of excessive line contact characteristics and contact stress between the wheels and rails of gantry cranes by employing a combination of microscopic morphological observation and macroscopic geometric testing to trace the root cause.

[0140] By using a laser diameter gauge to detect the macroscopic roundness (>0.1mm), the reduced contact area and increased stress caused by wheel out-of-roundness can be identified; at the same time, weld stress detection is used to investigate the indirect effects of wheel positioning deviation.

[0141] (2) Tracing the source of excessive torsional deformation of the main beam (for box-type main beams): If the torsional deformation exceeds the standard, stress wave tomography (frequency 2.5MHz, probe diameter 20mm) is used to detect the inside of the main beam: If a defect of ≥1mm is found, it is determined that the welding defect leads to insufficient stiffness (risk of rigid connection of gantry crane); if there is no defect, the track settlement gradient is detected. If it is >0.5mm / m, it is determined that the track is uneven and causes unilateral stress; at the same time, the torque of the support bolts is checked (M30 bolt ≥400N・m). If the torque is insufficient, it is determined that the support is loose.

[0142] This step addresses the characteristics of gantry crane box-type main beams, which have high torsional stiffness, small torsional deformation, and are mostly caused by internal defects or uneven external stress. It adopts a progressive tracing approach, including internal defect detection, external load investigation, and connection status verification.

[0143] (3) Tracing the source of excessive braking temperature (adapted to dual-side braking): If the braking temperature exceeds the standard, disassemble the braking device for inspection: use a feeler gauge to measure the brake shoe clearance. If the difference between the two sides is >0.2mm, it is determined that uneven wear leads to local overheating (gantry crane dual-side braking problem); use a hardness tester (HRC accuracy ±1) to measure the hardness of the friction pad. If HRC <25, it is determined that the friction pad material is deteriorated; check the brake cylinder oil pressure (31.5MPa). If the oil pressure is insufficient, it is determined that the braking thrust is insufficient, leading to sliding friction.

[0144] This step addresses the issue of excessive temperature in the double-sided brake shoe braking structure of gantry cranes by employing a disassembly-based tracing approach, involving structural gap detection, material performance verification, and power source investigation.

[0145] Excessive temperature on both sides of the brakes is mainly caused by uneven friction, decreased friction coefficient, or low braking efficiency. After disassembly, the difference in clearance between the two sides of the brake shoes is measured with a feeler gauge (>0.2mm) to identify local overheating caused by uneven wear, which is the most common cause of dual-side braking. The hardness of the friction pads is measured with a hardness tester (HRC<25) to identify the decrease in friction coefficient and increased sliding friction caused by material deterioration. The brake cylinder oil pressure is checked (below 31.5MPa) to identify incomplete braking and sliding friction caused by insufficient thrust, thus forming a complete traceability chain from structure to materials to power.

[0146] (4) Tracing the source of excessive impact acceleration (suitable for long tracks): If the impact acceleration exceeds the standard, check the depression in the track: use a track ruler to measure the depth of the depression. If it is >2mm, it is determined that the depression is too deep (which is common in long tracks of gantry cranes); if the depth of the depression is normal, check the wheel tread step. If the step is >3mm, it is determined that the step caused the impact; at the same time, check the trolley suspension system. If the spring stiffness is insufficient, it is determined that the suspension failure amplified the impact.

[0147] Impact acceleration is determined by both external excitation and internal buffer. Long tracks (10-50m) are prone to dents. The primary excitation source is identified by measuring the dent depth (>2mm) using a track gauge. If the excitation source is normal, the secondary excitation source is identified by measuring the wheel tread step (>3mm). At the same time, the spring stiffness of the suspension system is checked to identify the impact amplification caused by buffer failure, thus forming a traceability process for external excitation and internal buffer.

[0148] Based on any of the above technical solutions, the further optimization is that the targeted rectification in step 6 includes: (1) Wheel tread texture repair (adapted to unidirectional wear): If the texture is insufficient, laser cladding technology (fiber laser 500W) is used, iron-based alloy powder (particle size 50-150μm) is selected, powder feeding amount is 10g / min, protective gas argon (flow rate 15L / min), cladding layer thickness is 0.5-1mm, and the processed texture is net-like (valley depth 0.8-1.0mm); after cladding, the texture is detected by line laser scanning to ensure that the valley depth meets the standard, and at the same time, the hardness of the cladding layer is measured by hardness tester to be HRC≥30 (to ensure wear resistance), and the bonding strength is ≥300MPa (to avoid falling off); (2) Track depression repair (adapted to long track): if the track is depressed, arc welding is used to fill it (welding rod E5015, diameter 3.2mm), welding current 100-120A, welding speed 5mm / s, and after filling, the track top surface is ground with an angle grinder until the flatness is ≤0.1mm.

[0149] After grinding, use an ultrasonic thickness gauge to check the track thickness to ensure there is no false welding. At the same time, use a track ruler to check the height difference between the repair area and the surrounding track ≤0.05mm (to avoid impact caused by steps); (3) Repair of main beam weld defects (adapt to rigid connection): If the main beam has welding defects, use welding repair (welding rod E5015), open a V-shaped groove (angle 60°), welding current 120-150A, interpass temperature ≤250℃, and after welding repair, perform vibration aging (excitation frequency 20-50Hz, 20min) to eliminate residual stress ≤150MPa.

[0150] After aging, use an ultrasonic flaw detector to ensure that the defects are eliminated. At the same time, measure the torsional deformation angle of the main beam to ensure that it is ≤0.1° / m. According to common knowledge and industry standards in the field of art, it is necessary to explain the following: Beveling and cleaning requirements: According to GB / T985.1-2008 "Recommended beveling for gas welding, shielded metal arc welding, gas shielded welding and high energy beam welding", when the defect depth is ≤3mm, a single V-shaped beveling is opened, and when the depth is >3mm, a double V-shaped beveling is opened. The thickness of the blunt edge at the root of the beveling is 1-2mm and the gap is 2-3mm.

[0151] After processing, the bevel surface is ground with an angle grinder to a roughness Ra≤25μm, and then wiped with acetone to remove oil and oxide scale to ensure welding quality.

[0152] Interlayer temperature control measures: A type K thermocouple (accuracy ±2℃) is attached to the edge of the bevel 20mm to monitor the temperature in real time. When the temperature is >250℃, compressed air is used for forced cooling (wind speed ≤3m / s to avoid overcooling and cracking). The next layer of welding is carried out after the temperature drops to the range of 150-200℃.

[0153] The thickness of each weld layer is controlled at 3-4mm. After welding, the weld slag is cleaned with a wire brush, which meets the interlayer control requirements of JB / T4709-2000 "Welding Procedure Qualification of Steel Pressure Vessels".

[0154] Parameter matching and verification of vibration aging: The excitation point is selected at the connection between the support leg and the main beam on the same side of the defect repair area (the position with greater stiffness), and the support points are set at both ends of the main beam (1m away from the end plate, with rubber buffer pads).

[0155] The excitation force is adjusted according to the mass of the main beam: 5kN for ≤100t, 8kN for 100-200t, and 10kN for >200t; the resonance frequency is monitored by a vibration sensor (frequency response 0-100Hz) to ensure that the excitation frequency falls within ±2Hz of the resonance peak.

[0156] After aging, the residual stress is tested using the blind hole method (compliant with GB / T32705-2016 "Determination of Residual Stress of Metallic Materials by Blind Hole Method"). The test points cover the weld repair area and the surrounding 50mm range to ensure that the stress at all test points is ≤150MPa.

[0157] (4) Brake wear repair (suitable for dual-side brakes): If the brake wear is uneven, grind the brake shoes (grind wheel 120 mesh), adjust the difference in brake shoe clearance between the two sides to ≤0.2mm, and after grinding, check that the contact area of ​​the brake shoes is ≥80%.

[0158] If the friction pads are not hard enough, replace them (material: copper-based powder metallurgy, HRC25-30). After replacement, run them under no-load for 5 times and check that the braking temperature is ≤200℃ and the braking time is 0.5±0.05s (to ensure braking efficiency).

[0159] Based on any of the above technical solutions, a further optimization is to add a wheel-track contact state calibration sub-step in the multi-dimensional static calibration of step 1. This step is located after the track settlement gradient measurement and specifically includes: using a three-dimensional laser scanner (accuracy ±0.005mm) to collect wheel contact patch images every 5m along the entire track under the unloaded state of the trolley; measuring the ratio of the contact patch area to the wheel tread width, requiring the ratio to be ≥0.65; measuring the lateral offset of the contact patch geometric center relative to the wheel centerline, requiring the offset to be ≤5mm; if the above two indicators do not meet the requirements, correction is made through the horizontal guide wheel adjustment device of the trolley traveling mechanism (adjustment accuracy ±0.1mm), and data is re-collected after each adjustment until both indicators meet the requirements.

[0160] It should be noted that the actual contact area characteristics between the wheel and the track are obtained by three-dimensional laser scanning. The contact patch area ratio reflects the uniformity of the wheel load distribution (a low ratio indicates poor contact), and the lateral offset reflects the deviation of the trolley's travel trajectory (excessive offset can easily lead to rail wear).

[0161] The horizontal guide wheel adjustment device optimizes the contact state by making slight adjustments to the lateral position of the wheel, ensuring that the load is evenly transmitted to the track when the trolley is running.

[0162] Breaking away from the limitations of traditional methods that only measure single parameters such as wheel diameter and track spacing, this method directly obtains the actual contact state between the wheel and the track, covering two key characteristics: load distribution uniformity and track alignment.

[0163] In response to the characteristics of gantry cranes, such as large span, long stroke, and double-sided tracks, multiple sampling points are taken along the entire length of the track (1 measuring point every 5m) to avoid the randomness of single-point measurement and to better reflect the actual working conditions of the gantry crane's entire stroke.

[0164] Early warning of track wear risk: By continuously monitoring the offset of contact spots, potential wear trends can be detected before visible wear appears on the track (traditional methods require wear of more than 0.5mm to identify this), thus extending the service life of the track.

[0165] Reduce trolley operating energy consumption: After the contact patch area ratio meets the standard, the friction coefficient between the wheel and the rail is reduced, which reduces the trolley operating energy consumption and solves the problem of abnormally increased running resistance caused by poor contact in gantry cranes.

[0166] After optimizing the contact state, the uniformity of the braking force distribution between the wheels and the track is improved during emergency braking, and the amount of braking deviation can be effectively reduced, significantly reducing the risk of large vehicles overturning due to braking imbalance.

[0167] In addition, the uniform distribution of contact spots reduces the additional torque borne by the main beam, and the fatigue life of the main beam is expected to be extended, solving the problem that traditional calibration methods cannot alleviate structural fatigue.

[0168] Based on any of the above technical solutions, a further optimization is to add a multi-condition timing control sub-step in the fault coupling simulation of step 2, located after the fault parameter setting. Specifically, it includes: using a PLC timing controller to trigger the fault in the following order: start the trolley to travel to the rated speed (30m / min); trigger a local track indentation (depth 2mm) after 2 seconds; trigger a wheel tread step (height 3mm) and a momentary gust of wind (wind speed 20m / s) simultaneously after 3 seconds; trigger brake wear (50% increase in clearance on one side) and execute emergency braking after 4 seconds; during the fault simulation, apply a dynamic load to the mid-span of the main beam through the existing electro-hydraulic servo loading system, and set the load waveform according to the actual applicable working conditions (e.g., actual port operation frequency); control the 24 sensor data of the main beam (8 measuring points), outriggers (4 measuring points), and track (12 measuring points) to be synchronously fed back to the control center in real time.

[0169] It should be noted that during operation, the PLC timing controller presets fault triggering logic and activates various fault simulations sequentially according to the time sequence (0-4 seconds) of startup, obstacle triggering, compound fault, and emergency braking. This reproduces the continuous fault chain that the gantry crane may encounter in actual operation, ensuring that the time sequence of fault occurrence is consistent with the actual working conditions. Then, using the existing electro-hydraulic servo loading system, dynamic loads are applied to the mid-span of the main beam according to the actual frequency waveform of port operations (such as periodic load superimposed with random impact) during the fault simulation process, simulating the real stress state during container hoisting, making the fault coupling environment closer to the actual working scenario. Finally, the control system performs real-time calibration on 24 sensors distributed on the main beam (8), outriggers (4), and tracks (12), ensuring that the stress, deformation, vibration, and other data of each measuring point are collected synchronously in the time dimension and fed back to the control center, avoiding coupling analysis errors caused by data time difference.

[0170] The dynamic load waveform is set according to the actual port operation frequency to avoid the deviation between the general load model and the actual stress state, making the fault coupling effect more valuable for reference.

[0171] The system collects data simultaneously from 24 sensors, covering key structures such as the main beam, outriggers, and tracks. This provides a more comprehensive view than local sampling and can capture the force chain transmission patterns between components.

[0172] It can capture track indentations and main beam resonance caused by instantaneous gusts that cannot be identified by single fault testing, solving the problem of insufficient evaluation of complex fault response in traditional testing. It can then discover the hidden risks of multi-fault coupling. Through timing control, it can compress extreme fault combinations that may only occur in natural environments over several months into simulation within 4 seconds, significantly shortening the safety verification cycle of the entire equipment life cycle.

[0173] In addition, there is no need to interrupt operations at the actual port for fault testing. Extreme operating condition data can be obtained through laboratory time-series simulations before delivery, which greatly reduces the cost of a single test and avoids the safety risks of on-site testing.

[0174] In step 4, a hierarchical safety assessment sub-step is added to the coupling judgment, located after the multi-parameter coupling calculation. Specifically, it includes: establishing a three-level assessment index system: Level 1 index: structural safety (weight 0.4), braking safety (weight 0.3), and operational stability (weight 0.3); Level 2 index: structural safety includes contact stress ratio, torsional deformation angle, and weld stress; braking safety includes temperature rise rate and braking distance deviation; operational stability includes impact acceleration and amplitude; introducing a dynamic weight adjustment mechanism: when the wind speed is >15m / s, the braking safety weight is increased by 0.1; when the equipment has been in service for more than 10 years, the structural safety weight is increased by 0.1; outputting the three-level judgment results of safety / critical / unsafe, and marking the key influencing factors.

[0175] The specific adjustment method of the dynamic weight adjustment mechanism is as follows: When the wind speed is >15m / s: Braking safety weight: increased by 0.1 to 0.4 from the basic weight of 0.3; Operational stability weight: decreased by 0.1 to 0.2 from the basic weight of 0.3; Structural safety weight: kept unchanged at the basic weight of 0.4.

[0176] When equipment has been in service for more than 10 years: Structural safety weight: increased by 0.1 to 0.5 from the basic weight of 0.4; Operational stability weight: decreased by 0.1 to 0.2 from the basic weight of 0.3; Braking safety weight: kept unchanged at the basic weight of 0.3.

[0177] When the wind speed is greater than 15 m / s and the equipment has been in service for more than 10 years (overlapping conditions): Structural safety weight: increased by 0.1 to 0.5; Braking safety weight: increased by 0.1 to 0.4; Operational stability weight: decreased by 0.2 to 0.1.

[0178] Explanation of the weighting method for primary indicators: Among them, structural safety (weight 0.4): According to Chapter 4 of GB / T3811-2008 "Code for Design of Cranes", structural failure belongs to the highest level of risk, which may lead to equipment damage and personal injury, and should be given the highest priority in safety assessment.

[0179] In addition, based on industry accident statistics, structural fracture accidents account for 42% of all accidents involving gantry cranes, with an average direct economic loss of 2.3 million yuan per accident, and the severity of the risk consequences is higher than that of other systems.

[0180] Gantry cranes have structural characteristics of large span (20-50m) and high self-weight (thousands of tons). According to ISO12480-1 "Safety of cranes - Part 1: General", structural load-bearing capacity should be the primary evaluation indicator.

[0181] Among them, braking safety (weight 0.3): According to Article 6.2 of JT / T604-2019 "Safety Regulations for Port Cranes", braking system failure is a high-risk level, which may lead to accidents such as trolley slippage and cargo falling.

[0182] In addition, industry data shows that brake-related accidents account for 31% of all accidents involving gantry cranes, and when the wind speed exceeds 15 m / s, derailment accidents caused by brake failure account for 58%.

[0183] According to GB51249-2017 "Load Code for Port Engineering", the braking system must have a safety factor of more than 1.5 times to cope with extreme weather, and its reliability directly affects the safety of operation.

[0184] Among them, operational stability (weight 0.3): According to the ISO2631-1 standard "Evaluation of human body vibration exposure", the operational stability index is directly related to the fatigue life of equipment. Long-term excessive vibration will lead to structural fatigue damage, which accounts for 27% of aging failures.

[0185] Actual test data show that when the vibration acceleration exceeds 0.5g, the bolt loosening rate increases by 2.1 times, the brake pad wear rate increases by 40%, and there is an indirect impact on other safety systems.

[0186] It meets the requirements of GB / T24811-2019 "Limiting and Protective Devices for Cranes" and together with structural safety and braking safety, it constitutes a complete safety assessment system.

[0187] The aforementioned weighting percentages were selected in accordance with conventional choices in the field and common knowledge known to those skilled in the art, and have clear implementation basis and reproducibility.

[0188] It needs to be explained that the quantification and normalization methods for secondary indicators are as follows: ; (Initial temperature is the temperature of the friction pads before braking; braking time is the duration of emergency braking); (Standard braking distance is calculated according to the formula in GB / T3811-2008). (Permissible amplitude reference ISO2631-1 "Evaluation of human body vibration exposure"); all indicators are normalized to the range of [0,2], and those exceeding 2 are counted as 2, which complies with the quantitative evaluation principle of GB / T19001-2016 "Quality Management System Requirements".

[0189] The weights of the secondary indicators are determined by the Analytic Hierarchy Process (AHP): under structural safety, the contact stress ratio (0.4), torsional deformation angle (0.4), and weld stress (0.2); under braking safety, the temperature rise rate (0.6) and braking distance deviation (0.4); and under operational stability, the impact acceleration (0.5) and amplitude (0.5).

[0190] After consistency testing, the CR values ​​were all <0.1, which meets the requirements of mathematical rigor and is in line with the industry's consensus on prioritizing structural safety and focusing on braking performance.

[0191] The calculation logic of the overall score: .

[0192] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. For those skilled in the art, any alternative improvements or transformations made to the implementation of the present invention fall within the protection scope of the present invention.

[0193] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A method for testing the dynamic operational safety of a crane, characterized in that, include: Step 1, Multi-dimensional Static Calibration: Collect micro-texture of wheel tread, residual stress of main beam-outer leg weld, track foundation settlement gradient, environmental temperature and humidity correction coefficient, and trolley brake shoe clearance. Once all parameters meet the standards, proceed to the next step. Step 2, Fault Coupling Simulation: Simulate local steps on the wheel tread, local depressions in the track, uneven wear of the trolley brakes, and instantaneous gusts, while simultaneously collecting data on wheel contact stress distribution, track impact acceleration, main beam torsional deformation angle, and brake friction pad temperature field. Step 3, Structured Data Processing: The collected wheel contact stress distribution is processed using a bilinear interpolation algorithm to obtain complete stress data; the track impact acceleration is subjected to a 500Hz low-pass filter to extract impact features; the main beam torsional deformation angle is denoised by moving average to ensure the accuracy of deformation; and the brake friction pad temperature field is analyzed by isotherm analysis to extract temperature parameters. After extracting the feature values ​​of the above four types of data, time alignment is performed based on the synchronous trigger signal to ensure that the alignment deviation is ≤1ms. Step 4, Coupling Determination: Construct a multi-parameter model, introduce a large vehicle mass correction coefficient, and determine that the superposition coefficient ≥ 1.2 is unsafe; Step 5, root cause analysis: Scanning electron microscopy to observe the tread morphology, stress wave analysis to measure main beam defects, and brake clearance detection to locate the microscopic and macroscopic root causes; Step 6, targeted rectification: laser cladding repairs wheel texture, arc welding fills track depressions, brake shoe grinding, and retests dual parameters after rectification.

2. The method for testing the dynamic operation safety of a crane according to claim 1, characterized in that, The multi-dimensional static calibration mentioned in step 1 includes: Wheel texture acquisition: Line laser is used to take cross sections every 15° and 50 points are taken radially to calculate the valley depth. If the standard is not met, laser repair is performed. The valley depth is re-measured and Ra≤1.6μm, where Ra is the roughness. Weld stress acquisition: The stress is measured by the three-point blind hole method on the weld side. If the stress exceeds the standard, vibration aging is performed, and no defects ≥1mm are detected simultaneously. Track settlement data acquisition: The total station is used to calculate the gradient at points every 3m. If the gradient exceeds the standard, grouting is performed to raise the track. After re-measurement, the flatness is measured with a track gauge and is ≤0.1mm. Temperature and humidity correction: The sensor data parameters are used to calculate the coefficient. If the deviation is >2%, the material parameters are adjusted and recorded. Brake clearance acquisition: Use a feeler gauge to measure the clearance at 3 points on the brake shoe and calculate the difference between the two sides. If the difference exceeds the standard, adjust the push rod to ensure that the difference meets the standard and the contact area is ≥80%.

3. The method for testing the dynamic operation safety of a crane according to claim 2, characterized in that, The fault coupling simulation described in step 2 includes: Wheel step simulation: The grinding machine drills a 3mm deep and 50mm wide step in the outer 1 / 3 area of ​​the tread. The measured Ra is ≤3.2μm and the diameter deviation is ≤0.1mm. Track concavity simulation: Weld a 2mm deep and 100mm long groove at the mid-span, grind the edge radius to ≤0.5mm, measure the flatness to ≤0.2mm and the thickness to be within the standard; Brake wear simulation: Adjust the brake shoe clearance on one side to 1.5 times the design value, ensuring that one side is more than 50% larger than the other side, and the contact area is ≤70%; Gust simulation: The wind speed in the wind tunnel was increased to 20m / s via PLC control, and the vertical uniformity deviation of the main beam was monitored to be ≤5%; Parameter acquisition: stress is collected by track piezoelectric sensors; impact is collected by accelerometers on the concave side; torsion is collected by laser sensors on the main beam; and temperature field is captured by infrared thermal imagers. Parameter alignment deviation ≤ 1ms.

4. The method for testing the dynamic operation safety of a crane according to claim 3, characterized in that, The structured data processing described in step 3 specifically includes: (1) Wheel contact stress interpolation processing: Adapt to the uneven contact stress characteristics of wheel and rail lines, calculate the stress at any point based on the discrete values ​​of array sensors using bilinear interpolation algorithm, covering a 50mm contact width with an error ≤5%; extract the maximum contact stress at the wheel step and calculate its ratio to the material fatigue limit for subsequent judgment. (2) Track impact acceleration filtering: To adapt to the 200-500Hz high-frequency impact generated by the large vehicle passing over the indentation, a 500Hz Butterworth 10th order low-pass filter is used. After filtering, the peak value and duration of the impact are calculated to ensure that the peak value deviation is ≤3%; (3) Smoothing of the torsional deformation angle of the main beam: The torsional deformation angle is calculated by using a 5-point moving average filter to remove instantaneous interference; (4) Analysis of the temperature field of brake friction pads: Calculate the heating rate to determine brake thermal fade; (5) Multi-data synchronization alignment: Based on the synchronization trigger signal, align each parameter according to the timestamp, verify the correlation, resample if the deviation exceeds 1ms, and store the original and processed data for traceability.

5. The method for testing the dynamic operation safety of a crane according to claim 4, characterized in that, The coupling determination described in step 4 is as follows: (1) Parameter normalization: The mass of the gantry crane trolley (50-500t) has a significant impact on impact and braking. A correction coefficient k for the trolley mass is introduced. m Its calculation formula is Based on this coefficient, the eigenvalues ​​of each parameter are normalized: Normalized contact stress: Normalized peak impact: Normalized torsional deformation angle: Normalized temperature: ; (2) Coupled Model Construction: Using normalized parameters as input, a coupled decision model is constructed, and the safety factor is calculated. ;in: ; ; (3) Dynamic threshold setting: The threshold is dynamically adjusted according to the working conditions of the gantry crane: Full load condition: S>1.2 unsafe, 1.0≤S≤1.2 critical, S<1.0 safe; Half load condition: S>1.3 unsafe, 1.1≤S≤1.3 critical, S<1.1 safe; When the gust exceeds 20m / s: the threshold is lowered by 0.1; (4) Judgment Execution: Judgment is based on priority: structural safety > braking safety > contact safety. If... If it is directly judged as unsafe; If deemed unsafe; The S-value is used for judgment; if all parameters meet the standard and S < the threshold, it is considered safe. in, Let α be the contact stress, α be the impact acceleration, θ be the torsional deformation angle, and T be the temperature. For allowable impact value, For the heat resistance limit of friction plates, To allow for the use of twist angles.

6. The method for testing the dynamic operation safety of a crane according to claim 5, characterized in that, The root cause tracing mentioned in step 4 includes: (1) Tracing the source of excessive wheel contact stress: Scanning electron microscope to observe the tread surface, if the texture valley depth is <0.8mm, it is judged as insufficient texture, and if there is metal peeling, it is judged as contact fatigue; laser diameter gauge to check roundness, >0.1mm is judged as wheel out of roundness; (2) Tracing the source of excessive torsional deformation of the main beam: Stress wave tomography scan the main beam. If there is a defect ≥1mm, it is judged as a welding defect; if there is no defect, the track settlement gradient is measured. If it is >0.5mm / m, it is judged as track unevenness; at the same time, the torque of the outrigger bolts is checked. If it is insufficient, it is judged as loose outrigger. (3) Tracing the source of excessive braking temperature: Disassemble the braking device, measure the difference between the two sides of the brake shoe with a feeler gauge > 0.2 mm to determine uneven wear; measure the friction plate with a hardness tester HRC < 25 to determine material deterioration; check the hydraulic cylinder for insufficient oil pressure to determine insufficient thrust; (4) Tracing the source of excessive impact acceleration: If the depth of the dent measured by the track ruler is >2mm, it is considered too deep; if it is normal, check the wheel step >3mm to determine if the step caused it; at the same time, check the stiffness of the suspension spring of the large vehicle, if it is insufficient, it is considered suspension failure.

7. The method for testing the dynamic operation safety of a crane according to claim 6, characterized in that, The targeted rectification mentioned in step 6 includes: (1) Wheel tread texture repair: If the texture is insufficient, laser cladding is used; after cladding, the valley depth is measured by laser scanning and meets the standard, the hardness tester shows HRC≥30, and the bonding strength is≥300MPa; (2) Track dent repair: fill with arc welding, grind until flatness ≤0.1mm; ultrasonic thickness measurement to ensure no false welding, track ruler measurement of the height difference between the repair area and the surrounding area ≤0.05mm; (3) Repair of defects in main beam welds: repair welding, followed by vibration aging to relieve stress ≤150MPa; ultrasonic testing to ensure the elimination of defects, and measuring torsional deformation angle ≤0.1° / m; (4) Repairing brake wear: Grind the brake shoes, adjust the clearance difference between the two sides to ≤0.2mm, and measure the contact area to ≥80%; replace the friction pad if the hardness is insufficient, and run it under no-load for 5 times to ensure that the brake temperature is ≤200℃ and the time is 0.5±0.05s.

8. The method for testing the dynamic operation safety of a crane according to claim 7, characterized in that, A wheel-track contact state calibration sub-step is added to the multi-dimensional static calibration in step 1. This step is located after the track settlement gradient measurement and specifically includes: A 3D laser scanner is used to collect wheel contact patch images every 5m along the entire track when the trolley is unloaded. The ratio of the contact patch area to the wheel tread width is measured, and the ratio is required to be ≥0.

65. The lateral offset of the geometric center of the contact patch relative to the wheel centerline is measured, and the offset is required to be ≤5mm. If the above two indicators do not meet the requirements, they are corrected by adjusting the horizontal guide wheel of the trolley traveling mechanism. Data is re-collected after each adjustment until both indicators meet the requirements.

9. A method for testing the dynamic operation safety of a crane according to claim 8, characterized in that: In step 2, a multi-condition timing control sub-step is added to the fault coupling simulation. This sub-step is located after the fault parameter setting and specifically includes: The PLC timing controller triggers the fault in the following sequence: the trolley is started and travels to the rated speed; after 2 seconds, a local track indentation is triggered; after 3 seconds, a wheel tread step and a momentary gust of wind are triggered simultaneously; after 4 seconds, brake wear is triggered and emergency braking is executed; during the fault simulation, a dynamic load is applied to the mid-span of the main beam through the existing electro-hydraulic servo loading system, and the load waveform is set according to the actual applicable working conditions; the data from 24 sensors controlling the main beam, outriggers, and track are synchronously fed back to the control center in real time.

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