A method for ultrasonic stress detection of derrick steel structure

Abstract

The invention discloses an ultrasonic stress detection method for a derrick steel structure, which belongs to the field of safety detection of oil derricks. The device comprises a rotating platform, a center of gravity sensing mechanism, a first direction adjustment mechanism and a second direction adjustment mechanism which are connected in sequence from top to bottom along the height direction. The first direction adjustment mechanism comprises a first sliding groove and a first sliding block which can slide along the first sliding groove; the second direction adjustment mechanism comprises a second sliding groove and a second sliding block which can slide along the second sliding groove; the sliding direction of the first sliding groove is perpendicular to the sliding direction of the second sliding groove, and the first sliding block is fixedly connected to the second sliding groove; the second sliding block is connected to a detection component, and the stability and reliability of the detection are ensured by the cooperation of the center of gravity sensing mechanism and the direction adjustment mechanism. The built-in algorithm can accurately locate and mark the maximum stress area to achieve accurate stress elimination.

Description

Technical Field

[0001] The invention relates to the field of oil derrick safety detection, in particular to an ultrasonic stress detection method for a derrick steel structure. Background Art

[0002] As the core facility in the oil production process, the safety and stability of the oil derrick are directly related to the reliability of the entire oil production system and the life safety of the staff. The oil derrick steel structure will experience various complex external forces during the manufacturing, installation and use, such as welding, machining, gravity load, external impact, etc. These factors may cause residual stress inside the steel structure. Once the steel structure of the important parts of the derrick produces residual stress, it may cause adverse consequences such as reduced material strength, accelerated fatigue damage, structural stability and stiffness, and have a significant impact on the performance of the steel structure. In order to ensure the safe operation of the oil derrick, residual stress detection and evaluation must be carried out. It can significantly improve the safety and economy of oil production facilities and ensure the smooth progress of oil production.

[0003] The existing technology only conducts regular indiscriminate inspections on all derrick steel structures, and indiscriminately eliminates stress on steel structures with excessive residual stress. This process is time-consuming, labor-intensive, and costly, and lacks specificity. Summary of the invention

[0004] In view of the above problems, the present invention provides an ultrasonic stress detection device for a derrick steel structure, which can accurately locate the position of residual stress, improve the detection efficiency and maintenance efficiency, and ensure the safety and stability of the derrick.

[0005] The technical solution of the present invention is:

[0006] An ultrasonic stress detection device for a derrick steel structure comprises a rotating platform, a gravity center sensing mechanism, a first direction adjustment mechanism, and a second direction adjustment mechanism which are sequentially connected from top to bottom along a height direction, wherein the first direction adjustment mechanism and the second direction adjustment mechanism have the same structure;

[0007] The first direction adjustment mechanism comprises a first sliding groove and a first sliding block which can slide along the first sliding groove;

[0008] The second direction adjustment mechanism comprises a second sliding groove and a second sliding block which can slide along the second sliding groove;

[0009] The sliding direction of the first sliding groove is perpendicular to the sliding direction of the second sliding groove, and the first sliding block is fixedly connected to the second sliding groove;

[0010] The second sliding block is connected to a detection component.

[0011] The first sliding groove and the first sliding block form a screw-nut transmission pair, and the second sliding groove and the second sliding block form a screw-nut transmission pair.

[0012] A balancing weight is arranged at one end of the first sliding slot, and the balancing weight comprises a balancing weight plate and a balancing weight adjustment mechanism.

[0013] A drone connecting plate is arranged above the rotating platform.

[0014] The center of gravity sensing mechanism includes a positioning frame, a gravity ball arranged in the positioning frame, and a pressure sensor sleeved outside the positioning frame.

[0015] The detection assembly includes an ultrasonic probe, a coupling spray probe, a visual sensor and a marking pen.

[0016] The device also includes a processor and a wireless communication module. The processor is connected to the center of gravity sensing mechanism, the detection component, the wireless communication module, the first direction adjustment mechanism, the second direction adjustment mechanism, and the counterweight adjustment mechanism by signal.

[0017] The detection method based on the ultrasonic stress detection device for derrick steel structure is as follows:

[0018] S1. Construct a three-dimensional finite element analysis model of the derrick according to the derrick structure size, component specifications, component materials, and rod connection form;

[0019] S2. Conduct reliability analysis on the derrick based on the finite element analysis model to determine the most important steel structure;

[0020] S3. Use an ultrasonic stress detection device to perform stress detection on various positions of steel parts of the derrick and collect detection data;

[0021] S4. Calculate the residual stress based on the collected test data and mark the maximum stress area;

[0022] S5. Evaluate the derrick steel structure according to the data obtained in step S4.

[0023] In step S2, the reliability analysis method is as follows:

[0024] The Monte Carlo method is used to generate N random samples, perform stress analysis, and judge and count the number of simulated failures N according to the derrick failure criteria. f , calculate the failure probability P f , using the formula The failure probability is obtained, and the scores of different probabilities are calculated by the formula Calculated, where n represents P f The number of

[0025] Maintenance cost (M f )pass Determine the score of the repair cost;

[0026] The importance index I of the equipment is calculated by the formula Calculated;

[0027] Where n represents P f 、M f , α, β, and γ represent the different weights of the importance factors. The weights can be obtained through expert experience or multi-attribute decision-making methods. f is the impact of the failure on the derrick function.

[0028] In step S4, the collected data is filtered to remove abnormal values ​​and interpolated, and a neural network is used to fit the curve to calculate the stress value. The stress calculation formula is as follows:

[0029]

[0030] Where T L Ts and Ts are the acoustic time of stress longitudinal wave and stress shear wave, respectively. L , ε S are the longitudinal wave acoustic elastic coefficient and the transverse wave acoustic elastic coefficient, T L0 , T s0 are the acoustic time of zero stress longitudinal wave and the acoustic time of zero stress shear wave respectively, σ is the stress in the propagation direction of longitudinal wave and shear wave, θ is the angle, and Ф is the height coefficient.

[0031] The beneficial effects of the present invention are:

[0032] The center of gravity sensing mechanism and the direction adjustment mechanism cooperate to ensure the stability and reliability of the detection. This cooperation improves the detection accuracy, reduces the interference of environmental factors on the detection results, and enhances the adaptability of the equipment in complex environments.

[0033] This technology can not only locate stress concentration areas, but also adjust the elimination plan according to the detection results, realize targeted stress elimination treatment, improve structural safety and service life, and the built-in algorithm can accurately locate and mark the maximum stress area to achieve accurate stress elimination. This precise positioning capability greatly improves the efficiency and effect of stress elimination, and can be applied to similar industries for stress detection, suitable for stress detection and elimination in a variety of complex environments, and can be expanded to more fields of application, with a wide range of applications.

[0034] Compared with traditional methods, the present invention only performs stress detection on important steel structures and performs stress elimination in areas exceeding the stress threshold. The energy consumption in the stress elimination process is lower, more environmentally friendly, and in line with the current development trend of energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the overall structure of an ultrasonic stress detection device for a derrick steel structure according to an embodiment of the present invention;

[0036] Figure 2 It is a structural schematic diagram of a gravity sensing mechanism of an ultrasonic stress detection device for a derrick steel structure according to an embodiment of the present invention;

[0037] Figure 3 It is a structural schematic diagram of an ultrasonic stress detection device for a derrick steel structure according to an embodiment of the present invention;

[0038] Figure 4 This is a control module connection diagram of a derrick steel structure ultrasonic stress detection device according to an embodiment of the present invention;

[0039] Figure 5 It is a flow chart of a detection method of an ultrasonic stress detection device for a derrick steel structure according to an embodiment of the present invention.

[0040] Description of reference numerals:

[0041] 1 is a rotating platform, 2 is a center of gravity sensing mechanism, 3 is a first direction adjustment mechanism, 4 is a second direction adjustment mechanism, 5 is a detection component, 6 is a balancing weight, 7 is a UAV connecting plate, 21 is a positioning frame, 22 is a gravity ball, 23 is a pressure sensor, 31 is a first sliding groove, 32 is a first sliding block, 41 is a second sliding groove, 42 is a second sliding block, 51 is an ultrasonic probe, 52 is a coupling spray probe, 53 is a visual sensor, and 54 is a marking pen. DETAILED DESCRIPTION

[0042] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0043] Example:

[0044] like Figure 1-Figure 3 As shown, an ultrasonic stress detection device for a derrick steel structure comprises a rotating platform 1, a center of gravity sensing mechanism 2, a first direction adjustment mechanism 3, and a second direction adjustment mechanism 4, which are sequentially connected from top to bottom along the height direction. The first direction adjustment mechanism 3 and the second direction adjustment mechanism 4 have the same structure;

[0045] The first direction adjustment mechanism 3 includes a first sliding groove 31 and a first sliding block 32 that can slide along the first sliding groove 31;

[0046] The second direction adjustment mechanism 4 includes a second sliding groove 41 and a second sliding block 42 that can slide along the second sliding groove 41;

[0047] The sliding direction of the first sliding groove 31 is perpendicular to the sliding direction of the second sliding groove 41, and the first sliding block 32 is fixedly connected to the second sliding groove 41;

[0048] The second sliding block 42 is connected to the detection component 5 .

[0049] The working principle of the above technical solution is as follows:

[0050] The rotating platform 1 drives the gravity sensing mechanism 2, the first direction adjustment mechanism 3, and the second direction adjustment mechanism 4 at the bottom to rotate, thereby driving the detection component 5 to rotate. The device is placed on the steel structure to be detected by rotating the entire structure. The sliding groove and the sliding block of the first direction adjustment mechanism 3 and the second direction adjustment mechanism 4 are moved to realize the front and back, left and right movement of the detection component. The center of gravity of the device is adjusted by the gravity sensing mechanism 2 to ensure the reliability and stability of the detection.

[0051] The first sliding groove 31 and the first sliding block 32 form a screw-nut transmission pair, the second sliding groove 41 and the second sliding block 42 form a screw-nut transmission pair, and a balancing weight 6 is arranged at one end of the first sliding groove 31. The balancing weight 6 includes a counterweight plate and a counterweight adjustment mechanism. Through the screw-nut transmission mechanism, the reliability, safety and stability of the direction adjustment can be ensured, thereby ensuring the detection quality.

[0052] A drone connection plate 7 is arranged above the rotating platform 1. By connecting a drone through the drone connection plate 7, the inspection of steel structures at higher positions of the high derrick can be realized, and the drone can also be replaced with other power equipment.

[0053] The center of gravity sensing mechanism 2 includes a positioning frame 21, a gravity ball 22 arranged in the positioning frame 21, and a pressure sensor 23 mounted on the outside of the positioning frame 21. The gravity ball 22 in the positioning frame 21 hits the positioning frame 21, thereby driving the positioning frame 21 to collide with the pressure sensor 23. The center of gravity position of the entire device is determined based on the information fed back by the pressure sensor 23, and then the center of gravity of the entire device is adjusted to ensure that the entire device is in a relatively stable state and the reliability of the detection is ensured.

[0054] The detection component 5 includes an ultrasonic probe 51, a coupling spray probe 52, a visual sensor 53 and a marking pen 54. The coupling spray probe 52 is arranged in front of the ultrasonic probe 51, and the coupling agent can be sprayed in advance to improve the accuracy of ultrasonic probe detection. The visual sensor 53 is installed behind the ultrasonic probe 51 to observe the entire steel structure. The marking pen 54 is used to mark discrete points. The discrete point data can be collected through the visual sensor 53, which is convenient for forming a continuous curve after curve fitting of the discrete points of stress values.

[0055] like Figure 4As shown, the device also includes a processor and a wireless communication module. The processor is connected to the center of gravity sensing mechanism 2, the detection component 5, the wireless communication module, the first direction adjustment mechanism 3, the second direction adjustment mechanism 4, and the counterweight adjustment mechanism by signal, so as to realize the automatic operation of the detection.

[0056] like Figure 5 As shown, the detection method is as follows:

[0057] S1. Construct a three-dimensional finite element analysis model of the derrick according to the derrick structure size, component specifications, component materials, and rod connection form;

[0058] S2. Conduct reliability analysis on the derrick based on the finite element analysis model to determine the most important steel structure;

[0059] Determine the reliability index and the impact of failure on the derrick function (F f ), failure frequency (P f )、Maintenance costs(M f ) The three factors are determined as importance indicators, and the weights of the three factors are determined through experience or multi-attribute decision-making methods to determine the steel structure with the greatest importance;

[0060] The impact of failure on the derrick function (F f ) is obtained through finite element model analysis, and the failure frequency (P f ) is obtained through historical or Monte Carlo simulation.

[0061] Determine the impact level and classify it according to the following table:

[0062] Impact illustrate Points No impact Does not affect the use of the derrick 1 Less impact Degradation of derrick 2 Significant impact The derrick structure is unstable 3 Serious impact The derrick is unusable 4

[0063] If there is sufficient historical failure data, the failure frequency can be calculated using the historical data as the failure probability of the steel parts. Otherwise, a three-dimensional finite element model of the derrick is constructed, and N random samples are generated using the Monte Carlo method under different load conditions such as wind load and earthquake load. Stress analysis is performed and the number of simulated failures N is judged and counted according to the derrick failure criteria. f , calculate the failure probability P f , using the formula Finally, the failure probability is obtained, and the scores of different probabilities are calculated by the formula Calculated, where n represents P f The number of .

[0064] Maintenance cost (M f )pass Calculate the repair cost in points.

[0065] The importance index I of the equipment is calculated by the formula Calculated;

[0066] Where n represents P f 、M f , α, β, and γ represent the different weights of the importance factors, and the weights can be obtained through expert experience or multi-attribute decision-making methods.

[0067] S3. Use an ultrasonic stress detection device to perform stress detection on various positions of steel parts of the derrick and collect detection data;

[0068] First, the steel structure is divided into areas, and the signal values ​​of the divided areas are collected. The data obtained by the ultrasonic and visual sensors are stored and transmitted through the wireless communication module.

[0069] S4. Calculate the residual stress based on the collected test data and mark the maximum stress area;

[0070] The collected data is filtered to remove abnormal values ​​and interpolated, and then the curve is fitted using a neural network, and finally the stress value is calculated through a related algorithm;

[0071] The region is divided, (x, y, z) is the value of the location region point, and the stress coordinate matrix is ​​established. (x, y) is the position coordinate of a point, and z is the stress signal value of the point.

[0072] The filter removes outliers and uses median filtering to remove outliers. Set the window m×n to get Z[i,j]=median({x i+m ,y j+n ]}), and then pass the filtered data through the known four points (x1, y1, z 11 )、(x1,y2,z 12 )、(x2,y1,z 21 )、(x2,y2,z 22 ) performs interpolation calculation;

[0073]

[0074] The neural network fitting curve, for the forward propagation calculation, its weighted input and formula are as follows: The activation function is expressed as For back propagation, the loss function expression is: Its gradient calculation The update expressions of its weights and biases are: and

[0075] Where Z is the stress signal value, xy is the coordinate position, N is the number of samples, η is the learning rate, represents the weighted input sum of the jth neuron in the lth layer; represents the weight from the i-th neuron in the l-1th layer to the j-th neuron in the / th layer; The output value of the i-th neuron in the / -1 layer; represents the bias of the i-th neuron in the / th layer; f represents the activation function; represents the output value of the jth neuron in the lth layer after being processed by the activation function f; L represents the loss function; N represents the number of samples; y n Represents the true value of the nth sample; Represents the predicted value of the nth sample; represents the weighted input sum of the jth neuron in the Lth layer (output layer); Represents the loss function L with respect to the weighted input and jth neuron in the output layer The partial derivative of ; η represents the learning rate; Represents the loss function L with respect to weight The partial derivative of Denotes the loss function L with respect to the bias The partial derivative of .

[0076] Finally, the maximum value of the residual stress value σ is set by a predetermined algorithm or procedure. max Converted to stress signal value Z max .

[0077] Usually the formula Calculate the stress magnitude, where T L and T S It is related to the length of the steel structure being tested. However, during the testing process, the ultrasonic probe cannot be completely close to or parallel to the testing surface of the steel structure. Usually, there is a certain angle θ, which is related to the relative position of the center of gravity of the drone. The center of gravity of the drone can be obtained through the center of gravity sensing mechanism. Therefore, the stress formula is

[0078] Where T L Ts and Ts are the acoustic time of stress longitudinal wave and stress shear wave, respectively. L , ε S are the longitudinal wave acoustic elastic coefficient and the transverse wave acoustic elastic coefficient, T L0 , T s0 are the acoustic time of zero stress longitudinal wave and zero stress shear wave, σ is the stress in the propagation direction of longitudinal wave and shear wave, θ is the angle. Since the altitude of the drone is not exactly the same during flight, it can be represented by (x, y, h), where (x, y) is the position coordinate of a point and h is the flight altitude of the point. but

[0079] S5. Evaluate the derrick steel structure according to the data obtained in step S4.

[0080] First, use a brush to mark discrete points at the (x, y) point. After all points are calibrated, all discrete points are used through the visual system to draw closed stress areas according to the stress distribution characteristics. The closed stress area has been drawn during the calibration of the maximum stress area. Stress elimination technology or process can be used to reduce the residual stress in specific areas.

[0081] The above-mentioned embodiments only express the specific implementation of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for ultrasonic stress detection of a derrick steel structure, wherein the ultrasonic stress detection device used comprises a rotating platform, a center of gravity sensing mechanism, a first direction adjustment mechanism, and a second direction adjustment mechanism connected in sequence from top to bottom along the height direction, wherein the first direction adjustment mechanism has the same structure as the second direction adjustment mechanism; the first direction adjustment mechanism comprises a first sliding groove and a first sliding block that can slide along the first sliding groove; the second direction adjustment mechanism comprises a second sliding groove and a second sliding block that can slide along the second sliding groove; the sliding direction of the first sliding groove is perpendicular to the sliding direction of the second sliding groove, and the first sliding block is fixedly connected to the second sliding groove; the second sliding block is connected to a detection assembly, characterized in that The steps include: S1. Construct a three-dimensional finite element analysis model of the derrick according to the derrick structure size, component specifications, component materials, and rod connection form; S2. Conduct reliability analysis on the derrick based on the finite element analysis model to determine the most important steel structure; S3. Use an ultrasonic stress detection device to perform stress detection on various positions of steel parts of the derrick and collect detection data; S4. Calculate the residual stress based on the collected test data and mark the maximum stress area; S5, evaluating the derrick steel structure according to the data obtained in step S4; In step S4, the collected data is filtered to remove abnormal values ​​and interpolated, and a neural network is used to fit the curve to calculate the stress value. The stress calculation formula is as follows: Where T L Ts and Ts are the acoustic time of stress longitudinal wave and stress shear wave, respectively. L , ε S are the longitudinal wave acoustic elastic coefficient and the transverse wave acoustic elastic coefficient, T L0 、T s0 are the acoustic time of zero stress longitudinal wave and the acoustic time of zero stress shear wave, σ is the stress in the propagation direction of longitudinal wave and shear wave, θ is the angle, and Ф is the height coefficient.

2. The ultrasonic stress detection method for a derrick steel structure according to claim 1 is characterized in that: In step S2, the reliability analysis method is as follows: The Monte Carlo method is used to generate N random samples, perform stress analysis, and judge and count the number of simulated failures N according to the derrick failure criteria. f , calculate the failure probability P f , using the formula The failure probability is obtained, and the scores of different probabilities are calculated by the formula Calculated, where n represents P f The number of Maintenance costM f pass Determine the score of the repair cost; The importance index I of the equipment is calculated by the formula Calculated; Where n represents P f 、M f , α, β, and γ represent the different weights of the importance factors, and the weights are calculated through expert experience or multi-attribute decision-making methods. f is the impact of the failure on the derrick function.

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