Oil and gas pipeline stress damage comprehensive judgment method based on magnetic memory method

Abstract

The invention belongs to the technical field of metal stress damage detection, and particularly relates to an oil and gas pipeline stress damage comprehensive judgment method based on a magnetic memory method. In order to solve the problem that the stress damage state of the pipeline is difficult to comprehensively detect, the invention provides the design of the comprehensive judgment method for the stress damage of the oil and gas pipeline based on the magnetic memory detection principle. Firstly, the magnetic memory detection method can detect the stress damage of the ferromagnetic material based on the natural magnetomechanical characteristics of the ferromagnetic material. Secondly, according to the system experiment research, when the ferromagnetic material is excited, the main stress magnetic memory signal value can be changed, but when the magnetic line direction of the excitation coil is perpendicular to the main stress magnetic memory signal direction, the main stress magnetic memory signal value is not changed, and the characteristic can be used for judging the main stress direction of the pipeline. Based on the magnetic memory detection principle, an intelligent control method for system units such as multiple groups of magnetic memory detection probes, excitation coils, filtering systems and the like and a digital program acquisition and analysis processing method for detection signals such as magnetic memory signal values, magnetic memory signal values in different excitation directions and the like are utilized; the invention designs an oil and gas pipeline stress damage comprehensive judgment method based on a magnetic memory method.

Description

Technical Field

[0001] The invention belongs to the technical field of metal stress damage detection, and in particular relates to a comprehensive determination method for stress damage of an oil and gas pipeline based on a magnetic memory method. Background Art

[0002] Pipeline transportation has many advantages, such as large transportation volume, no restrictions on the environment and other ground factors, low cost and continuous operation. It is a way of transporting oil and natural gas. However, due to the material problems of the oil and gas pipeline itself and the damage caused by construction, corrosion and external forces, the pipeline will produce stress concentration phenomenon, and then form stress damage, which will cause the pipeline condition to deteriorate continuously and pose a great potential danger. It may even cause deformation, cracks or even fracture of the pipeline, causing explosion and oil leakage. Therefore, the detection of oil and gas pipeline stress is crucial. However, due to the complexity of stress distribution and the limitations of detection technology, the degree of stress damage of oil and gas pipelines is difficult to judge. The degree of stress damage of oil and gas pipelines mainly depends on the size of stress concentration and the direction of principal stress, both of which are important bases for judging and evaluating the reliability and safety status of pipelines. However, detecting pipeline stress, especially the direction of principal stress, is a complex problem. The stress distribution of pipelines is very complex, including axial stress, circumferential stress and oblique stress. The interaction of these stresses makes it difficult to accurately determine the direction of principal stress. In summary, pipeline stress detection is crucial to ensure the safe operation of oil and gas pipelines. However, there is currently a lack of suitable methods to comprehensively evaluate the stress state of pipelines. Summary of the invention

[0003] In view of the above problems, the present invention designs a comprehensive determination method for stress damage of oil and gas pipelines based on the magnetic memory detection principle. First, the magnetic memory detection method itself can detect stress damage of ferromagnetic materials based on the natural magnetomechanical properties of ferromagnetic materials. Secondly, through our systematic experimental research, it is found that when the ferromagnetic material is excited, the value of the principal stress magnetic memory signal will change, but when the direction of the magnetic lines of force of the excitation coil is perpendicular to the direction of the principal stress magnetic memory signal, the value of the principal stress magnetic memory signal remains unchanged. This characteristic can be used to determine the direction of the principal stress of the pipeline. Based on the above magnetic memory detection principle, a comprehensive determination method for stress damage of oil and gas pipelines based on the magnetic memory method is designed by using an intelligent control method for multiple groups of magnetic memory detection probes, excitation coils, filtering systems and other system units, and a digital program for collecting and analyzing detection signals such as magnetic memory signal values ​​and magnetic memory signal values ​​of different excitation directions.

[0004] The main program of the detection system first defines the parameters of the magnetic memory signal storage area, defines the two-dimensional array Dectiondate as the magnetic memory signal detection data storage area of ​​different excitation directions; the one-dimensional array Standard is used as the magnetic memory signal value storage area; the one-dimensional array Direction is the direction detection data storage area; the main program of the detection system divides and numbers a plurality of detection probes and motors by defining the array, and then calls the magnetic memory signal acquisition subroutine, obtains the magnetic memory signals of the stepper motors at different acquisition monitoring points when they are not rotating as the magnetic memory signal values ​​and puts them into the magnetic memory signal value storage unit Standard, which is used as the basis data for determining the degree of stress damage and as the intermediate parameter for determining the direction of the main stress and waits for calling, and then opens the magnetic memory detection probes and stepper motors corresponding to the different acquisition monitoring points in the loop, and starts the magnetic memory signal acquisition subroutines of different excitation directions, and calls the acquisition stress damage comprehensive analysis and judgment subroutine after completing data acquisition in all detection areas, and outputs and displays the stored data in the magnetic memory signal value storage unit Standard and the direction detection data storage unit Direction as the stress value and the main stress direction respectively after processing.

[0005] The hardware system controlled by the system program includes: a system external structure, a detection system control unit, and a stepper motor excitation unit, wherein the system external structure includes an adjustment device, an external protection frame, a detection ring, and a connecting rod, wherein the external protection frame is composed of a plurality of arc-shaped components distributed in a circular array, constituting the external frame of the stress detection system and providing external protection for the system; the detection ring is installed on the outside of the oil and gas pipeline and is used to place a plurality of groups of magnetic memory detection probes and stepper motors and other equipment; the adjustment device and the connecting rod are arranged on the detection ring and are used to adjust the distance between the detection ring and the pipeline body and the external protection frame, and to fix the detection ring at a specified position; the detection system control unit includes an excitation coil, a magnetic memory detection probe, a stepper motor, a motor drive, a conversion controller, a filtering system, an A / D converter, an STM single-chip microcomputer, an external memory, an infrared transmission system, and a PC. The magnetic memory detection probe is used to obtain the magnetic memory signal of the acquisition monitoring point under different excitation directions and transmit the acquired magnetic signal to the STM single chip microcomputer through the filtering system and the A / D converter for data processing. The system drives the stepper motor to rotate through the STM single chip microcomputer control conversion controller. The stepper motor excitation unit includes an excitation coil, a stepper motor, and a motor drive. The motor drive controls the stepper motor to rotate synchronously to drive the excitation coil, which is used to provide the acquisition monitoring point with an external magnetic field with different excitation directions. Under the control of the main program of the detection system, the STM single chip microcomputer can use the magnetic memory signal acquisition subroutine and the magnetic memory signal acquisition subroutine with different excitation directions to collect digital magnetic memory signals without excitation (magnetic memory signal value) and under different excitation directions for each acquisition monitoring point, and the acquired signal is analyzed by digital calculation of the stress damage comprehensive analysis and judgment subroutine to determine the stress damage state of the acquisition monitoring point.

[0006] The magnetic memory signal acquisition subroutine first defines the variable R0 and uses it as a pointer to the magnetic memory signal value storage unit Standard corresponding to the current detection probe, defines the maximum number of cycles for acquisition, defines R2 and R3 as cycle counting units, with an initial value of 0, turns on the conversion switch, and accumulates the magnetic memory signal values ​​collected in the cycle to R0. After reaching the maximum number of cycles, the average value of R0 is calculated, and the average value is stored in the standard value storage area Standard[N] ​​as the standard value of the magnetic memory signal in the area. At the same time, N++ is used to collect the magnetic memory signal of the next detection area. After multiple cycles, the magnetic memory detection probe, the filtering system, and the A / D converter are turned on respectively to detect the magnetic memory signal, and the magnetic memory signal is stored in the magnetic memory signal value storage unit Standard after system analysis and processing, thereby completing the magnetic memory signal acquisition of each acquisition monitoring point.

[0007] The subroutine for collecting magnetic memory signals of different excitation directions first puts the first address of the forward table of the stepper motor into the data pointer DPTR, defines the loop count R1, and sets the maximum value to 20. It is assumed that the content pointed to by the pointer DPTR is put into TURN as the output value of the motor. The motor driver motorPutput outputs the value of TURN, and the stepper motor rotates one step, that is, it rotates a certain angle. That is, by controlling the rotation of the stepper motor to drive the change of the excitation field, different excitation directions are provided for the magnetic memory signal of the monitoring point, and the pointer offset DPTR is updated to point to the next unit of the forward table. The pointer R0 is defined and points to the corresponding detection The magnetic memory signal detection area storage area of ​​the area starts the digital-to-analog conversion channel and stores the converted value in the R0 pointing area, that is, the magnetic memory signal value of the pipeline surface under different excitation directions is collected through the magnetic memory detection probe, and the value of J is automatically increased in the loop to adjust the storage area of ​​the detection data. After multiple cycles, the stepper motor rotates a certain angle, and the sensor also collects multiple data and puts them into the data acquisition storage area. After the cycle ends, the magnetic memory signals of 360 degrees in different excitation directions are stored in the detection data storage unit Detection of different excitation directions, completing the excitation and signal acquisition of different directions of the corresponding acquisition monitoring point.

[0008] The stress damage comprehensive analysis and judgment subroutine first sets the value of the first bit N of the acquisition data storage two-dimensional array to be 1, that is, processing starts from the data storage area corresponding to the first sensor, and then uses a for loop to circulate and screen the data storage area of ​​the corresponding sensor, so that the value of the second bit J of the acquisition data storage two-dimensional array is 1, and after completing one cycle, the value of J is incremented, and the data pointer P2 points to the current data storage area to be processed Detection[N][J], and determines whether the value of the current P2 pointing area is the same as the value of the corresponding unit of the initial value storage area. If the value of the current P2 pointing area is different from the value of the corresponding unit of the initial value storage area, J is incremented to continue the comparison. If they are the same, the current J value is stored as the data position record value in the data position storage unit Direction[N], and the value of N is incremented to compare the data in the storage area corresponding to the next detection probe, and the value of A is incremented to make P2 point to the next unit of the initial value storage area, and then continue the above cycle, and then compare and analyze the data in the different excitation direction detection data storage unit Detection and the magnetic memory signal value storage unit Standard[A], find out the same data in the two groups of storage units, and store them in the direction detection data storage unit Direction as the main stress direction determination data.

[0009] The invention has beneficial effects.

[0010] 1. The present invention uses an intelligent program to control multiple groups of external magnetic memory detection probes to realize magnetic memory signal detection at different collection and monitoring points of the pipeline. And the digital analysis program is written using the magnetic memory stress detection characteristics to process the collected magnetic memory signals and realize the analysis and processing of the stress damage degree of the collection and monitoring points.

[0011] 2. The present invention provides a method for intelligently controlling the excitation unit of a stepper motor, thereby providing excitation magnetic fields in different directions to each acquisition monitoring point, and utilizing the coupling characteristics of the direction of the magnetic lines of force of the excitation coil and the direction of the principal stress magnetic memory signal to form a digital analysis program, thereby realizing the analysis and processing of the principal stress direction of the acquisition monitoring point.

[0012] 3. The present invention provides a method for comprehensively calculating and analyzing stress damage degree data and principal stress direction detection data to achieve dual judgment on stress damage degree and direction, thereby ensuring accurate real-time warning and safe operation of oil and gas pipelines.

[0013] 4. The present invention can more accurately and timely discover the stress damage caused by the pipeline through the cyclic monitoring and real-time early warning of the pipeline stress and main stress direction of the system, reduce operating risks and safety hazards, and provide an important basis for the maintenance and repair of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. The protection scope of the present invention is not limited to the following description.

[0015] Figure 1 : Diagram of comprehensive stress damage detection system.

[0016] Figure 2 : Flow chart of the main program of the detection system.

[0017] Figure 3 : Magnetic memory signal acquisition subroutine flow chart.

[0018] Figure 4 : Flowchart of the subroutine for collecting magnetic memory signals in different excitation directions.

[0019] Figure 5 : Flowchart of the stress damage comprehensive analysis and judgment subroutine.

[0020] Figure 6 :Connection diagram of microcontroller controlled stepper motor.

[0021] Figure 7 : Connection diagram between conversion controller and motor drive part.

[0022] Figure 8(a): AMR magnetoresistive sensor structure diagram.

[0023] Figure 8(b): AMR magnetoresistive sensor circuit diagram.

[0024] Fig. 9 : Filtering system.

[0025] Fig.10 :Data acquisition system.

[0026] Fig.11 : Infrared signal transmission system. DETAILED DESCRIPTION

[0027] like Figure 1 As shown, the system of the present invention includes: a detection system control unit 1, a stepper motor excitation unit 2, wherein the external structure of the system includes an adjustment device 3, an external protection frame 4, a detection ring 5, and a connecting rod 6, wherein the external protection frame 4 is composed of a plurality of arc-shaped components distributed in a circular array, constituting the external frame of the stress detection system and providing external protection for the system; the detection ring 5 is installed on the outside of the oil and gas pipeline, and is used to place multiple groups of magnetic memory detection probes 10 and stepper motors 7 and other equipment; the adjustment device 3 and the connecting rod 6 are arranged on the detection ring 5, and are used to adjust the distance between the detection ring 5 and the pipeline body and the external protection frame 4, and fix the detection ring 5 at a specified position; the detection system control unit 1 includes an excitation coil 15, a magnetic memory detection probe 10, a stepper motor 7, a motor drive 8, a conversion controller 9, a filtering system 11, an A / D converter 12, an STM single-chip computer 17, an external memory 13, an infrared transmission system 14, and a PC 16. The magnetic memory detection probe 10 is used to obtain the magnetic memory signal of the acquisition monitoring point under different excitation directions and transmit the acquired magnetic signal to the STM single chip computer 17 through the filtering system 11 and the A / D converter 12 and perform data processing. The system controls the conversion controller 9 through the STM single chip computer 17 to drive the stepper motor 7 to rotate. The stepper motor excitation unit 2 includes a magnetic coil 4, a stepper motor 7, and a motor drive 8. The motor drive 8 controls the stepper motor 7 to rotate synchronously and drives the excitation coil 5 to provide an external magnetic field with different excitation directions for the acquisition monitoring point; the STM single chip computer 17 can be controlled by the main program of the detection system, using the magnetic memory signal acquisition subroutine and the magnetic memory signal acquisition subroutine with different excitation directions to collect digital magnetic memory signals without excitation (magnetic memory signal value) and under different excitation directions for each acquisition monitoring point, and the collected signal is analyzed by digital calculation of the stress damage comprehensive analysis and judgment subroutine to determine the stress damage state of the acquisition monitoring point.

[0028] like Figure 2As shown, the main program of the detection system first defines the parameters of the magnetic memory signal storage area, defines the two-dimensional array Dection date as the magnetic memory signal detection data storage area of ​​different excitation directions; the one-dimensional array Standard is used as the magnetic memory signal value storage area; the one-dimensional array Direction is the direction detection data storage area; the main program of the detection system divides and numbers the multiple magnetic memory detection probes 10 and the stepper motor 7 by defining the array, and then calls the magnetic memory signal acquisition subroutine, obtains the magnetic memory signal of the stepper motor 7 at different acquisition monitoring points when it is not rotating as the magnetic memory signal value and puts it into the magnetic memory signal value storage unit Standard, which is used as the basis data for determining the degree of stress damage and as the intermediate parameter for determining the main stress direction to be called, and then opens the magnetic memory detection probes 10 and the stepper motor 7 corresponding to different acquisition monitoring points in the loop, and starts the magnetic memory signal acquisition subroutine for different excitation directions, and calls the acquisition stress damage comprehensive analysis and judgment subroutine after completing data acquisition in all detection areas, and outputs and displays the storage data in the magnetic memory signal value storage unit Standard and the direction detection data storage unit Direction as the stress value and the main stress direction respectively after processing.

[0029] like Figure 3 As shown, the magnetic memory signal acquisition subroutine first defines the variable R0 and uses it as a pointer to the magnetic memory signal value storage unit Standard corresponding to the current detection probe, defines the maximum number of cycles for acquisition, defines R2 and R3 as cycle counting units, with an initial value of 0, turns on the conversion switch, and accumulates the magnetic memory signal values ​​collected in the cycle to R0. After reaching the maximum number of cycles, the average value of R0 is calculated, and the average value is stored in the standard value storage area Standard[N] ​​as the standard value of the magnetic memory signal in the area. At the same time, N++ is used to collect the magnetic memory signal of the next detection area. After multiple cycles, the magnetic memory detection probe, the filtering system, and the A / D converter are turned on to detect the magnetic memory signal, and the magnetic memory signal is stored in the magnetic memory signal value storage unit Standard after system analysis and processing, completing the magnetic memory signal acquisition of each acquisition monitoring point.

[0030] like Figure 4As shown, the magnetic memory signal acquisition subroutine of different excitation directions first puts the first address of the stepper motor forward table into the data pointer DPTR, defines the loop count R1, and the maximum value is 20. It is assumed that the content pointed to by the pointer DPTR is put into TURN as the output value of the motor. The motor driver motorPutput outputs the value of TURN, and the stepper motor 7 rotates one step, that is, it rotates a certain angle. That is, by controlling the rotation of the stepper motor to drive the excitation field to change, 3 different excitation directions are provided for the magnetic memory signal of the monitoring point, and the pointer offset DPTR is updated to point to the next unit of the forward table. The pointer R0 is defined and points to the corresponding detection The magnetic memory signal detection area storage area of ​​the measuring area is started, the digital-to-analog conversion channel is started, and the converted value is stored in the R0 pointing area, that is, the magnetic memory signal value of the pipeline surface under different excitation directions is collected by the magnetic memory detection probe, and the value of J is automatically increased in the loop to adjust the storage area of ​​the detection data. This cycle is repeated many times, and the stepper motor rotates a certain angle. The sensor also collects multiple data and puts them into the data acquisition storage area. After the cycle is completed, the magnetic memory signals of 360 degrees in different excitation directions are stored in the Detection data storage unit of different excitation directions, completing the excitation and detection signal collection of different directions of the corresponding acquisition monitoring point.

[0031] like Figure 5 As shown, the stress damage comprehensive analysis and judgment subroutine first sets the value of the first bit N of the two-dimensional array of data acquisition and storage to 1, that is, processing starts from the data storage area corresponding to the first sensor, and then uses a for loop to cyclically screen the data storage area of ​​the corresponding sensor, so that the value of the second bit J of the two-dimensional array of data acquisition and storage is 1, and after completing one cycle, the value of J is incremented, and the data pointer P2 points to the current data storage area to be processed Detection[N][J], and determines whether the value of the current P2 pointing area is the same as the value of the corresponding unit of the initial value storage area. If the value of the current P2 pointing area is different from the value of the corresponding unit of the initial value storage area, J is incremented to continue the comparison. If they are the same, the current J value is stored as the data position record value in the data position storage unit Direction[N], and the value of N is incremented to compare the data in the storage area corresponding to the next detection probe, and the value of A is incremented to make P2 point to the next unit of the initial value storage area, and then continue the above cycle, and then compare and analyze the data in the different excitation direction detection data storage unit Detection and the magnetic memory signal value storage unit Standard[A], find out the same data in the two groups of storage units, and store them in the direction detection data storage unit Direction as the main stress direction determination data.

[0032] like Figure 6As shown, the STM single-chip microcomputer 17 controls the rotation of the stepper motor 7 by utilizing the conversion controller 9 and the motor driver 8, and drives the excitation coil 15 to rotate to obtain the external excitation magnetic field in different directions, and the specific connection mode is as follows: the STM32G407RC single-chip microcomputer 17 is connected to the UIM2051 conversion controller 9 through the RS232-TTL conversion interface, and the signal input port of the conversion controller 9 is connected to the signal output port of the single-chip microcomputer 17, and the high and low bit lines of the UIM2501 conversion controller 9 are respectively connected to the CH and CL interfaces of the UIM242 motor driver 8 through twisted pairs, and the A, B, C, and D interfaces of the UIM242 motor driver 8 are respectively connected to the interface of the stepper motor 7. To realize the control of the stepper motor 7 by the single-chip microcomputer 17.

[0033] like Figure 7 As shown, the conversion controller 9 realizes the control of multiple stepper motor drivers 8 through the CAN bus structure, so that a UIM2501 conversion controller can control several stepper motors 6 in the CAN bus structure to realize the simultaneous detection of multiple points to be detected in the pipeline to be detected. The specific connection method is: the CH and CL interfaces of the UIM2501 conversion controller 9 are respectively connected to the high-order line CANH and the low-order line CANL, and are respectively connected to the stepper motor 7, and its twisted pair uses its 120 ohm impedance twisted pair, and the UIM242 motor drivers 8 are connected in parallel to each other to realize the control of several stepper motors 7 by the single-chip microcomputer 17.

[0034] As shown in FIG8 , the magnetic memory detection probe 10 uses an AMR magnetoresistive sensor, which is composed of a wire, an insulating substrate, a Permalloy, a pin, etc., and a shielding and protective shell. The AMR magnetoresistive sensor realizes magnetic memory signal detection based on the magnetoresistive effect. When encountering an external magnetic field, the resistance value will change with the size of the external magnetic field. As shown in FIG8 (b), the internal circuit of the magnetic memory detection probe 10 includes a Wheatstone bridge composed of four magnetoresistances, in which the power supply is Vb, and the current flows through the magnetoresistance. When a bias magnetic field H is applied to the bridge, the magnetization direction of the two oppositely placed resistors will rotate in the direction of the current, and the resistance of the two resistors will increase; while the magnetization direction of the other two oppositely placed resistors will rotate in the opposite direction of the current, and the resistance of the two resistors will decrease. By testing the output difference voltage signal at the two output ends of the bridge, the external magnetic field value can be obtained. Then, after the amplification circuit and signal filtering, the result is output to the filtering system through Vout.

[0035] like Fig. 9As shown, the filtering system 11 includes a multi-stage LM324 signal amplifier and an RC buffer circuit. The detection signal is transmitted to the input port of the A / D converter after multi-stage filtering. The specific connection method is: the signal input port of the filtering system 11 is connected to the signal output port of the magnetic memory detection probe 10, and the output port of the filtering system 11 is connected to the input port of the data acquisition module. The magnetic memory signal is sent to the input port of the data acquisition module after the interference signal is removed by the filtering circuit.

[0036] like Fig.10 As shown, the data acquisition system includes an analog-to-digital converter ADS1232 and is connected to multiple magnetic memory detection probes 10 through an analog switch MAX4620. The analog switch MAX4620 controls the opening of the magnetic memory detection probes at the corresponding points and transmits the signals to the ADS1232 to realize signal detection of multiple detection points. The STM32G407RC microcontroller 17 forms a memory expansion part through 628128 chips and 74LS373 latch chips to increase the storage capacity of the detection data. The microcontroller 17 is connected to multiple external excitation coils through SM245TS. The specific connection method is as follows: the signal input port of the analog switch is connected to the signal output port of the filter system, the P2.0, P2.1, and P2.2 interfaces of the STM32G407RC microcontroller 14 are respectively connected to the LBEN, HBEN, and CE of the ADS1232, the signal output port of the MAX4620 is connected to the IN port of the AD1232, and the A0-A7 ports of the storage expansion part 628128 are respectively connected to the P0.0-P0.7 of the microcontroller through the latch 74LS373. The P1.4, P1.3, and P1.2 interfaces of the microcontroller are respectively connected to the B0, B1, and B2 interfaces of the SM245TS, and the A0-A5 interfaces of the SM245TS are respectively connected to multiple excitation coils.

[0037] like Fig.11 As shown, the infrared transmission system 14 includes two parts, a transmitting part and a receiving part, which are respectively connected to the STM32G407RC single-chip microcomputer 17 and the PC 16 to realize signal transmission. The transmitting part is composed of an IR333C transmitting tube driven by an amplifier circuit, and the receiving part is composed of a TSOP4838 receiving tube and an LM386 comparator. The specific connection method is: the infrared transmitting part is connected to the signal output port of the single-chip microcomputer 17, the infrared receiving part is connected to the PC 16, the input port Vin of the infrared transmitting part is connected to the signal output port of the single-chip microcomputer 17, after receiving the signal of the single-chip microcomputer 17, the IR333C is driven to transmit the infrared signal after being amplified by a diode, and the signal of the infrared receiving part is amplified by LM393DT and then input into the PC 16, so as to realize the signal transmission between the STM32G407RC single-chip microcomputer 17 and the PC 16.

[0038] The method can be divided into a magnetic memory signal acquisition part and a magnetic memory signal processing part.

[0039] In the main program of the detection system of the magnetic memory signal acquisition part, the relevant detection data storage area is first defined, and the stepper motor and detection probe of the corresponding detection area are divided to realize separate control. The magnetic memory signal acquisition subroutine is run to collect magnetic memory signals without external excitation. The magnetic memory signals of multiple detection areas are collected separately through the loop program. The magnetic memory signal acquisition program repeatedly collects the magnetic memory signals on the pipeline surface in the maximum number of cycles, stores them in the corresponding storage area through the pointer, and finally puts the collected average into the magnetic memory signal value storage area. The magnetic memory signal acquisition subroutine of different excitation directions puts the motor forward table address into the motor output through the data pointer, and updates the offset and performs data acquisition in the loop to realize the acquisition of magnetic memory signals under different excitation angles.

[0040] The signal processing program uses the pointer to read the detection data of the corresponding tangential and normal data storage areas, and judges in the loop whether the pointer pointing value is the same as the magnetic memory signal value during data acquisition. If they are the same, the current cycle number is stored in the data position storage unit as the direction judgment address. If they are different, the pointer is updated to continue data screening, that is, through the stress damage comprehensive analysis and judgment subroutine, the magnetic memory signal under different excitation directions and the Standard storage unit data are digitally calculated and analyzed, and the principal stress direction judgment data is extracted and stored in the data position storage unit Direction unit waiting for call. Based on the detection characteristics of the pipeline surface magnetic memory signal under different excitation directions, the judgment data of the stress value and principal stress direction in the Standard and Direction storage units are used respectively to realize the dual judgment of the pipeline and the stress value and principal stress direction.

[0041] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the protection scope of the present invention.

Claims

1. A method for comprehensively determining stress damage of oil and gas pipelines based on a magnetic memory method. The main program of the detection system of the present invention first defines the parameters of a magnetic memory signal storage area, defines a two-dimensional array Dection date as a magnetic memory signal detection data storage area of ​​different excitation directions; a one-dimensional array Standard as a magnetic memory signal value storage area; and a one-dimensional array Direction as a direction detection data storage area. The main program of the detection system divides and numbers a plurality of detection probes and motors by defining arrays, and then calls a magnetic memory signal acquisition subroutine to obtain magnetic memory signals of stepper motors at different acquisition monitoring points when they are not rotating and put them into a magnetic memory signal value storage unit Standard as magnetic memory signal values, which are used as basis data for determining the degree of stress damage and as intermediate parameters for determining the direction of the principal stress to be called. Then, the magnetic memory detection probes and stepper motors corresponding to different acquisition monitoring points are opened in a loop, and magnetic memory signal acquisition subroutines of different excitation directions are started. After data acquisition is completed in all detection areas, the acquisition stress damage comprehensive analysis and judgment subroutine is called. After processing, the stored data in the magnetic memory signal value storage unit Standard and the direction detection data storage unit Direction are output and displayed as stress value magnitude and principal stress direction respectively. The hardware system controlled by the system program includes: The system external structure, the detection system control unit, and the stepper motor excitation unit, wherein the system external structure includes an adjustment device, an external protection frame, a detection ring, and a connecting rod, wherein the external protection frame is composed of a plurality of arc-shaped components distributed in a circular array, constituting the external frame of the stress detection system and providing external protection for the system; the detection ring is installed on the outside of the oil and gas pipeline, and is used to place a plurality of sets of magnetic memory detection probes and stepper motors and other equipment; the adjustment device and the connecting rod are arranged on the detection ring, and are used to adjust the distance between the detection ring and the pipeline body and the external protection frame, and to fix the detection ring at a specified position; the detection system control unit includes an excitation coil, a magnetic memory detection probe, a stepper motor, a motor drive, a conversion controller, a filtering system, an A / D converter, an STM single-chip microcomputer, an external storage device, an infrared transmission system, and a PC; the magnetic memory detection probe is used to obtain acquisition monitoring The system collects magnetic memory signals of points under different excitation directions and transmits the collected magnetic signals to the STM single-chip computer through the filtering system and the A / D converter for data processing. The system drives the stepper motor to rotate through the STM single-chip computer control conversion controller. The stepper motor excitation unit includes a magnetic coil, a stepper motor, and a motor drive. The stepper motor is controlled by the motor drive to rotate and synchronously drive the excitation coil to provide an external magnetic field with different excitation directions for the collection monitoring point. Under the control of the main program of the detection system, the STM single-chip computer can use the magnetic memory signal collection subroutine and the magnetic memory signal collection subroutine with different excitation directions to collect digital magnetic memory signals without excitation (magnetic memory signal value) and under different excitation directions for each collection monitoring point, and the collected signals are analyzed by digital calculation of the stress damage comprehensive analysis and judgment subroutine to determine the stress damage state of the collection monitoring point.

2. According to claim 1, a comprehensive determination method for stress damage of oil and gas pipelines based on magnetic memory method is characterized in that The magnetic memory signal acquisition subroutine of the present invention first defines a variable R0 and uses it as a pointer to point to the magnetic memory signal value storage unit Standard corresponding to the current detection probe, defines the maximum number of cycles for acquisition, defines R2 and R3 as cycle counting units, with an initial value of 0, turns on the conversion switch, and accumulates the magnetic memory signal values ​​collected in the cycle to R0. After reaching the maximum number of cycles, the average value of R0 is calculated, and the average value is stored in the standard value storage area Standard[N] ​​as the standard value of the magnetic memory signal in the area. At the same time, N++ is used to collect the magnetic memory signal of the next detection area. Thus, after multiple cycles of processing, the magnetic memory detection probe, the filtering system, and the A / D converter are turned on respectively to detect the magnetic memory signal, and the magnetic memory signal is stored in the magnetic memory signal value storage unit Standard after system analysis and processing, thereby completing the magnetic memory signal acquisition of each acquisition monitoring point.

3. According to claim 1, a comprehensive determination method for stress damage of oil and gas pipelines based on magnetic memory method is characterized in that As described above, the magnetic memory signal acquisition subroutine of different excitation directions of the present invention first puts the first address of the stepper motor forward table into the data pointer DPTR, defines the cycle count R1, and the maximum value is 20. It is assumed that the content pointed to by the pointer DPTR is put into TURN as the output value of the motor, and the motor driver program motorPutput outputs the value of TURN, then the stepper motor rotates one step, that is, it rotates a certain angle, that is, by controlling the rotation of the stepper motor to drive the excitation field to change, provide different excitation directions for the magnetic memory signal of the monitoring point, update the pointer offset DPTR to point to the next unit of the forward table, define the pointer R0 and point to the corresponding The magnetic memory signal detection area storage area of ​​the detection area starts the digital-to-analog conversion channel and stores the converted value in the R0 pointing area, that is, the magnetic memory detection probe is used to collect the magnetic memory signal value of the pipeline surface under different excitation directions. The value of J is automatically increased in the loop to adjust the storage area of ​​the detection data. This cycle is repeated many times, and the stepper motor rotates a certain angle. The sensor also collects multiple data and puts them into the data acquisition storage area. After the cycle ends, the magnetic memory signals of 360 degrees in different excitation directions are stored in the detection data storage unit Detection of different excitation directions, completing the excitation and signal acquisition in different directions of the corresponding acquisition monitoring point.

4. According to claim 1, a comprehensive determination method for stress damage of oil and gas pipelines based on magnetic memory method is characterized in that As described above, the stress damage comprehensive analysis and judgment subroutine of the present invention first sets the value of the first bit N of the two-dimensional array of data acquisition and storage to 1, that is, processing starts from the data storage area corresponding to the first sensor, and then the data storage area of ​​the corresponding sensor is cyclically screened through a for loop, so that the value of the second bit J of the two-dimensional array of data acquisition and storage is set to 1, and after completing one loop, the value of J is incremented, and the data pointer P2 points to the current data storage area to be processed Detection[N][J], and it is judged whether the value of the current P2 pointing area is the same as the value of the corresponding unit of the initial value storage area. If the value of the current P2 pointing area is not the same as the value of the corresponding unit of the initial value storage area, J is incremented to continue the comparison. If they are the same, the current J value is stored as the data position record value in the data position storage unit Direction[N], and the value of N is incremented to compare the data in the storage area corresponding to the next detection probe, and the value of A is incremented to make P2 point to the next unit of the initial value storage area, and then continue the above loop, and then compare and analyze the data in the different excitation direction detection data storage unit Detection and the magnetic memory signal value storage unit Standard[A], find out the same data in the two groups of storage units, and store them in the direction detection data storage unit Direction as the main stress direction determination data.

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