Crankshaft surface magnetization field uniformity evaluation method for aviation nondestructive testing

Abstract

The invention discloses a crankshaft surface magnetization field uniformity evaluation method for aviation nondestructive testing, and relates to the technical field of nondestructive testing, and the method comprises the following steps: carrying out detection pretreatment on a to-be-tested crankshaft to obtain a tested crankshaft, applying a forward magnetic field to the crankshaft according to a magnetic powder detection method, carrying out magnetic field intensity acquisition on the applied magnetic field, and calculating the uniformity of the applied magnetic field; obtaining a first magnetic field intensity signal; acquiring three-dimensional attributes of the tested crankshaft, dividing the crankshaft according to the three-dimensional attributes to obtain areas with the same attributes, analyzing the first magnetic field intensity signals on the areas with the same attributes, and determining abnormal signals existing in the first magnetic field intensity signals; determining the position of the crack based on the abnormal information to obtain first position information; and performing magnetic field change judgment on the first magnetic field intensity signal based on the first position information, determining a crack form, obtaining real position information in combination with the first position information, and outputting the real position information. The method has the effect of improving the crankshaft defect judgment accuracy.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of nondestructive testing, in particular to a method for evaluating the uniformity of a surface magnetization field of a crankshaft in aviation nondestructive testing. BACKGROUND

[0002] As a core load-bearing component, the surface and near-surface defects (such as cracks and fatigue damage) of an aero-engine crankshaft directly threaten flight safety. Magnetic particle testing (MT) has become the mainstream technology for nondestructive testing of aviation crankshafts due to its high sensitivity and convenient operation. However, the detection reliability is highly dependent on the uniformity of the magnetization field: if the angle between the magnetic field direction and the main plane of the defect is less than 45° or the distribution is uneven, the leakage magnetic field strength is significantly weakened, leading to the risk of missed detection.

[0003] In the prior art, the detection of crankshaft defects is basically dependent on magnetic particle testing, which can only detect surface cracks and cannot detect internal conditions, leading to missed detection during defect inspection of the crankshaft. At the same time, since the crankshaft is not composed of a single material, the magnetic field generated during magnetic particle testing is different due to uneven material distribution, which easily leads to magnetic field overflow, thereby reducing the accuracy of defect judgment of the crankshaft based on the magnetic powder condition. SUMMARY

[0004] In order to improve the accuracy of the judgment of the crankshaft defects, the application provides a method for evaluating the uniformity of a surface magnetization field of a crankshaft in aviation nondestructive testing.

[0005] The application provides a method for evaluating the uniformity of a surface magnetization field of a crankshaft in aviation nondestructive testing, which adopts the following technical solution:

[0006] A method for evaluating the uniformity of a surface magnetization field of a crankshaft in aviation nondestructive testing, comprising:

[0007] Before detecting the crankshaft, a test crankshaft is obtained by pretreatment, and a forward magnetic field is applied to the crankshaft according to the magnetic particle testing method, and the magnetic field strength of the applied magnetic field is collected to obtain a first magnetic field strength signal;

[0008] The three-dimensional properties of the test crankshaft are obtained, and the crankshaft is divided according to the three-dimensional properties to obtain regions with the same properties, and the first magnetic field strength signal on the regions with the same properties is analyzed to determine the abnormal signals in the first magnetic field strength signal;

[0009] Based on the abnormal information, the theoretical magnetic field strength where the abnormal information is located is determined, and the theoretical magnetic field strength is compared with the first magnetic field strength signal to determine the magnetic field strength difference;

[0010] Based on the magnetic field characteristics of the conductor, the current difference value in the magnetic field strength difference state is determined, the current data in the magnetic powder detection method is combined with the current difference value to determine the shunt caused by the crack, and the shunt data is obtained;

[0011] Based on the shunt data and the three-dimensional attribute in the corresponding area, the position of the crack is determined, and the first position information is obtained;

[0012] Based on the first position information, the magnetic field change of the first magnetic field strength signal is judged, the magnetic field strength change relationship is determined, the crack morphology is determined according to the magnetic field strength change relationship, the real position information is obtained combined with the first position information, and the real position information is output.

[0013] Preferably, according to the application direction of the applied forward magnetic field, the magnetic field strength on the rest space of the crankshaft is collected by using the Hall sensor, the magnetic field data with directionality is obtained, and the magnetic field data with directionality is marked as the first magnetic field strength signal.

[0014] Preferably, the test crankshaft is divided based on the three-dimensional attribute of the test crankshaft, the same attribute area under the same three-dimensional attribute is obtained, the first magnetic field strength signal on the same attribute area is statistically analyzed, and the magnetic field fluctuation range of each same attribute area is obtained.

[0015] The first magnetic field strength signal is screened according to the magnetic field fluctuation range of the same attribute area, the first abnormal signal is determined, and the first crankshaft range corresponding to the first abnormal signal is determined according to the detection range of the Hall sensor corresponding to the first abnormal signal.

[0016] Preferably, the current data in the magnetic powder detection method is obtained, and the theoretical magnetic field strength of each same attribute area is simulated according to the current data, and the theoretical magnetic field strength on each same attribute area is obtained.

[0017] The theoretical magnetic field strength is coupled according to the positional relationship between each same attribute area, and the simulation magnetic field data is obtained.

[0018] The simulation magnetic field data and the actually detected first magnetic field strength signal are compared to determine the abnormal points of the first magnetic field strength signal compared with the simulation magnetic field data, and the second abnormal signal is obtained.

[0019] The second abnormal signal is tested for crankshaft position marking, and the second crankshaft range is obtained.

[0020] The second crankshaft range and the first crankshaft range corresponding to the first abnormal signal are compared, if the second crankshaft range and the first crankshaft range are the same, it is determined that the crankshaft range has defects;

[0021] If the second crankshaft range and the first crankshaft range are different, it is determined that the first crankshaft range and the second crankshaft range do not have defects.

[0022] Preferably, the first magnetic field intensity signal on the corresponding position information is read and compared based on the first position information, and the magnetic field intensity change on the first position information is determined;

[0023] If the magnetic field intensity change on the first position information is uniform, it is determined that the crack form inside the crankshaft is a uniform form;

[0024] If the magnetic field intensity change on the first position information has central symmetry, it is determined that the crack form inside the crankshaft is a symmetric form;

[0025] If the magnetic field intensity change on the first position information has no regularity, it is determined that the crack form inside the crankshaft is an irregular form;

[0026] When the crack form inside the crankshaft is a uniform form, the first position information is output as the position information of the crack;

[0027] When the crack form inside the crankshaft is a symmetric form, a magnetic field is applied to the undetected direction according to the symmetry, and the crack position of the crankshaft is judged according to the applied magnetic field to obtain second position information, and the real position information of the crack is obtained based on the first position information and the second position information and output;

[0028] When the crack form inside the crankshaft is an irregular form, a magnetic field is applied to the undetected direction according to the first forward magnetic field, and the crack position of the crankshaft is judged according to the applied magnetic field to obtain third position information under the corresponding magnetic field, and the third position information is integrated to obtain the real position information of the crack.

[0029] Preferably, an arbitrary position point is selected in the interval of the test crankshaft corresponding to the first position information, and the first magnetic field intensity signal is read according to the selected position point to obtain first magnetic field sub-data under the corresponding position;

[0030] The first magnetic field sub-data are matched with each other to determine whether there are two magnetic field sub-data with equal numerical values, and if it is determined that there are only two positions with the same magnetic field intensity, the magnetic field intensity on the same horizontal line is compared with the two positions as the starting point and the current direction as the direction to determine whether the magnetic field intensity on the same horizontal line is equal;

[0031] If it is determined that the magnetic field intensity on the same horizontal line is equal, it is determined that the magnetic field intensity change on the first position information is uniform;

[0032] If it is determined that the magnetic field strengths on the same horizontal line are not equal, it is determined that the magnetic field strength change on the first position information is not uniform, and the first magnetic field sub-data is subjected to magnetic field strength matching, the positions with equal magnetic field strengths are marked to obtain marked positions, and the marked positions are subjected to collinearity determination;

[0033] If it is determined that there are equal magnetic field strengths and the marked positions are collinear, it is determined that the magnetic field strength change on the first position information is centrally symmetric;

[0034] If it is determined that there are no equal magnetic field strengths or there are equal magnetic field strengths but the marked positions are not collinear, it is determined that the magnetic field change on the first position information is irregular.

[0035] Preferably, the detection range of the magnetic powder detection method is obtained, the detection range of the magnetic powder detection method is compared with the real position information determined, and it is determined whether the real position information is within the detection range of the magnetic powder detection method;

[0036] If it is determined that the real position information is within the detection range of the magnetic powder detection method, the magnetic powder detection result is obtained, and the magnetic powder detection result is compared with the real position information, if the magnetic powder detection method detects a crack at the corresponding position, the magnetic powder detection result is output as the final detection result;

[0037] If the magnetic powder detection method does not detect a crack at the corresponding position, it is determined that the magnetic field evaluation is wrong, and the evaluation is re-performed;

[0038] If it is determined that the real position information is not within the detection range of the magnetic powder detection method, the real position information is output as the final detection result.

[0039] Preferably, the third position information determined on the undetected orientation is obtained, and the third position information is integrated based on the three-dimensional properties of the test crankshaft to determine whether the third position information is for the same crack, and comprehensive position information is obtained;

[0040] If the third position information is at the same position of the test crankshaft, it is determined that the third position information corresponds to the same crack, and the comprehensive position information is output as the real position information of the crack;

[0041] If the third position information is not at the same position of the test crankshaft, it is determined that the detection is wrong, and the third position information is re-determined.

[0042] In summary, the present application has at least one of the following beneficial technical effects:

[0043] 1. By utilizing existing mature magnetic particle testing methods, the feasibility of the solution is ensured. By leveraging magnetic field characteristics, the crankshaft is divided according to its three-dimensional properties, and the first magnetic field strength signal is analyzed based on the division. This makes the identified abnormal signals more targeted, improves the quality of the data to be analyzed, and thus makes the crack identification results more accurate. By utilizing magnetic field characteristics, the changes in the first magnetic field strength signal at corresponding locations are judged to determine the manifestation of the crack in the crankshaft, making the crack identification results more accurate. This allows decision-makers to determine the application scope of the tested crankshaft based on the crack situation, ensuring the safety of aerospace crankshafts.

[0044] 2. By using the current data and three-dimensional properties of each region with the same attribute in the magnetic particle testing method, a magnetic field simulation is performed to obtain the theoretical magnetic field strength of each region with the same attribute. The theoretical magnetic field strengths of each region with the same attribute are then coupled to obtain the simulated magnetic field data of the entire test crankshaft. By comparing the simulated magnetic field data with the first magnetic field strength signal obtained from actual detection, abnormal points under the simulated magnetic field data are screened out. Furthermore, by comparing the abnormal points obtained in the two cases, the correctness of the location of the crankshaft defect is verified, thus improving the accuracy of crankshaft defect judgment.

[0045] 3. By comprehensively utilizing the first position information, the first magnetic field strength signal on the first position information is analyzed to determine the special characteristics of the crack in the current magnetic field. Different position judgment methods are adopted according to the special characteristics of the crack in the magnetic field, so that the final position of the crack is accurate and reliable, thereby improving the decision-maker's accuracy in the crankshaft and ensuring aviation safety. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating the steps of the crankshaft surface magnetization field uniformity evaluation method for aerospace nondestructive testing in this embodiment. Detailed Implementation

[0047] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0048] This application discloses a method for evaluating the uniformity of magnetization field on the surface of a crankshaft in aerospace nondestructive testing.

[0049] Example: Figure 1 As shown, the present invention provides a method for evaluating the uniformity of magnetization field on a crankshaft surface in aerospace nondestructive testing, comprising:

[0050] S1, before the detection of the test crankshaft, the crankshaft is pre-processed to obtain the test crankshaft, and a positive magnetic field is applied to the crankshaft according to the magnetic powder detection method, the magnetic field strength of the applied magnetic field is collected, and the first magnetic field strength signal is obtained; Specifically, according to the direction of the applied positive magnetic field, the magnetic field strength on the rest space of the crankshaft is collected by using the Hall sensor to obtain the directional magnetic field data, and the directional magnetic field data is marked as the first magnetic field strength signal. Wherein, the positive magnetic field refers to the magnetic field direction when the magnetic field is applied for the first time.

[0051] S2, obtain the three-dimensional attribute of the test crankshaft, and divide the crankshaft according to the three-dimensional attribute to obtain the same attribute area, and analyze the first magnetic field strength signal on the same attribute area to determine the abnormal signal existing in the first magnetic field strength signal; Wherein, the three-dimensional attribute refers to the length, width and height of the crankshaft.

[0052] S3, based on the abnormal information, the theoretical magnetic field strength where the corresponding abnormal information is located is determined, and the theoretical magnetic field strength is compared with the first magnetic field strength signal to determine the magnetic field strength difference; Because when there is a crack in the crankshaft, if the crankshaft is regarded as a solid cylinder, the crack will convert the originally solid cylinder into a hollow cylinder in part of the area, and due to the irregularity of the crack, the hollow cylinder can be regarded as two parallel resistors, and then combined with the direction of the current, according to the right-hand rule, it can be judged that the direction of the surrounding magnetic field formed by the two parallel resistors is consistent, so that the surrounding magnetic field located in the middle of the two resistors will be cancelled out, thereby weakening the overall magnetic field, so when the theoretical magnetic field simulation is carried out, the simulated magnetic field is greater than the first magnetic field strength signal actually collected, so when the difference value is calculated, the difference value is the result of the mutual cancellation of the surrounding magnetic field, and then the current distribution is determined according to the magnetic field strength difference.

[0053] S4, based on the magnetic field characteristics of the conductor, the current difference under the magnetic field strength difference state is determined, based on the current data in the magnetic powder detection method and combined with the current difference, the shunt caused by the crack is determined to obtain the shunt data; The calculation formula of the magnetic field strength B outside the cylinder is: , wherein B is the magnetic field strength, is the vacuum permeability (constant), I is the current, and r is the radius.

[0054] S5, based on the shunt data and the three-dimensional attribute of the corresponding area, the position of the crack is determined to obtain the first position information; The shunt rule of the parallel resistor is: , and the calculation formula of the resistor R is: , wherein is the resistivity (constant) of the material; L is the length of the wire; A is the cross-sectional area of the wire.

[0055] S6, judging the magnetic field change based on the first position information, determining the magnetic field strength change relationship, and determining the crack form according to the magnetic field strength change relationship, and obtaining the real position information combined with the first position information and outputting.

[0056] In the embodiment, the executability of the scheme is ensured by using the existing mature magnetic powder detection method, the crankshaft is divided according to the three-dimensional properties of the crankshaft by using the magnetic field characteristics, and the first magnetic field strength signal is analyzed according to the division, so that the abnormal signal obtained by the judgment is targeted, the data quality of the to-be-analyzed data is improved, so that the judgment result is more accurate when judging the crack, the change of the first magnetic field strength signal at the corresponding position is judged by using the magnetic field characteristics, so as to determine the form of the crack in the crankshaft, so that the judgment result of the crack is more accurate, and then the decision maker can determine the application range of the test crankshaft according to the crack condition, and the safety of the aviation crankshaft is ensured.

[0057] For example, during the magnetic powder detection of the crankshaft, the surface of the crankshaft is cleaned and rusted to reduce the influence, and current is applied to the two ends of the treated crankshaft to form a surrounding magnetic field. In the present application, the surrounding magnetic field on the surface of the crankshaft is collected by using a Hall sensor to obtain the magnetic field data in each direction.

[0058] Suppose the crankshaft is a cylinder, and because the cross-sectional area of the cylinder is different, the resistance of the corresponding cylinder is different, and then the divided current size is different, and the current size affects the size of the magnetic field (the larger the current, the larger the magnetic field strength). Therefore, by dividing the crankshaft according to its three-dimensional properties, the crankshaft is divided into multiple segments, and each segment is judged separately, so that the analysis result of the first magnetic field strength signal analysis is more accurate.

[0059] Suppose the crankshaft is a cylinder, when there is a crack in the crankshaft, it can be considered that the crack converts the original solid cylinder into a hollow ring. Because the position of the crack is not necessarily concentric with the cylinder, the hollow ring can be regarded as two parallel wires. Therefore, when the entire crankshaft is evaluated by dividing it into multiple parts, the magnetic field of the same wire should be the same. When the magnetic field is different, it indicates that there is a different situation in the segment of the wire, which may be caused by the crack. Therefore, the situation is marked. The detection range of the Hall sensor is limited, so the different magnetic field regions can be further divided by using the Hall sensor, thereby further reducing the crankshaft region to be evaluated and the magnetic field data, simplifying the evaluation data amount, and improving the evaluation efficiency and evaluation accuracy.

[0060] When the abnormal point is determined by comparison, the Hall sensor can only determine the section of the crankshaft where the abnormal point is located, but cannot determine the specific depth of the abnormal point, so it is necessary to analyze the abnormal signal according to the three-dimensional attribute, first determine the possibility by using the abnormal signal, then judge the possibility by combining the three-dimensional attribute, so as to determine the position of the crack under the positive magnetic field. For example, the abnormal signal is A, and the possibility of reaching A under the current I is a, b, and c, and the three-dimensional attribute of the crankshaft can only satisfy a, so the position of the crack can be judged as a. For example, the cross-sectional area of the wire is M when there is no crack, and the magnetic field C will be generated under the cross-sectional area M and the current I. When there is a crack, the crack can divide the wire with cross-sectional area M into n groups, and only a group can reach the magnetic field A among the n groups, so the position of the crack is preliminarily judged.

[0061] However, since the crack is not necessarily parallel to the wire, it is necessary to determine whether the crack is parallel or symmetrical according to the current magnetic field strength, so as to further determine the performance of the crack in the crankshaft, and then output the performance of the crack in the crankshaft, so that the decision maker can evaluate the application range of the crankshaft, such as application in the field of aviation, automobile, machinery, etc.

[0062] Suppose that the cylinder has A and B ends, and the magnetic field formed by applying current from A to B is called positive magnetic field, and the magnetic field formed by applying current from B to A is called reverse magnetic field.

[0063] In step S2, the three-dimensional attribute of the test crankshaft is obtained, and the test crankshaft is divided according to the three-dimensional attribute to obtain the same attribute region, and the first magnetic field strength signal on the same attribute region is analyzed to determine the abnormal signal existing in the first magnetic field strength signal, including the following steps:

[0064] S21, based on the three-dimensional attribute of the test crankshaft, the test crankshaft is divided to obtain the same attribute region under the same three-dimensional attribute, and the first magnetic field strength signal on the same attribute region is statistically analyzed to obtain the magnetic field fluctuation range of each same attribute region;

[0065] S22, according to the magnetic field fluctuation range of the same attribute region, the first magnetic field strength signal is screened to determine the first abnormal signal, and according to the detection range of the Hall sensor corresponding to the first abnormal signal, the first crankshaft range corresponding to the first abnormal signal is determined.

[0066] In this embodiment, the crankshaft is divided by using the three-dimensional properties of the test crankshaft to ensure the uniformity of the generation object of the first magnetic field strength signal in the same property region, so that the data quality of the first magnetic field strength signal to be analyzed is improved to some extent. Then, the magnetic field fluctuation of the first magnetic field strength signal is judged to ensure the magnetic field fluctuation caused by the uneven material in the same property region, reduce the misjudgment, and make the abnormal signal obtained by analyzing the divided first magnetic field strength signal with the magnetic field fluctuation range as a reference more accurate, improve the accuracy of the crankshaft defect judgment, and according to the corresponding relationship between the first magnetic field strength signal and the Hall sensor and the corresponding relationship between the Hall sensor and the crankshaft, the position of the crankshaft defect is preliminarily judged to provide more accurate data to be judged for subsequent judgment and improve the accuracy of the judgment.

[0067] For example, due to the different cross sections of the crankshaft and the unevenness of the material, the magnetic field formed under the same current is different. Therefore, in order to ensure the quality of the data during analysis, the crankshaft is divided according to the three-dimensional properties of the crankshaft to ensure the same cross section, and then the magnetic field strength data of the same cross section is analyzed by mathematical statistics to determine the magnetic field fluctuation caused by the unevenness of the material of the crankshaft. Then, when the magnetic field strength data of the same cross section is screened according to the fluctuation, the result of the screening is more accurate. After the abnormal signal is screened out, the abnormal signal is read from the collection end to determine the position information of the Hall sensor and the crankshaft corresponding to the Hall sensor. The position of the defect in the crankshaft is preliminarily determined.

[0068] In step S2, the three-dimensional properties of the test crankshaft are obtained, and the crankshaft is divided according to the three-dimensional properties to obtain the same property region. The first magnetic field strength signal on the same property region is analyzed to determine the abnormal signal existing in the first magnetic field strength signal, including the following steps:

[0069] S23, obtaining the current data in the magnetic powder detection method, and simulating the theoretical magnetic field strength of each same property region according to the current data to obtain the theoretical magnetic field strength on each same property region;

[0070] S24, coupling the theoretical magnetic field strength according to the positional relationship between each same property region to obtain the simulated magnetic field data;

[0071] S25, comparing the simulated magnetic field data with the actually detected first magnetic field strength signal to determine the abnormal points existing in the first magnetic field strength signal compared with the simulated magnetic field data, and obtaining the second abnormal signal;

[0072] S26, marking the position of the test crankshaft on the second abnormal signal to obtain the second crankshaft range;

[0073] S27, compare the second crankshaft range with the first crankshaft range corresponding to the first abnormal signal, if the second crankshaft range is the same as the first crankshaft range, it is determined that the crankshaft range has defects;

[0074] S28, if the second crankshaft range is different from the first crankshaft range, it is determined that the first crankshaft range and the second crankshaft range do not have defects.

[0075] In this embodiment, the current data of the magnetic powder detection method and the three-dimensional attributes of each attribute region are used for magnetic field simulation, so that the theoretical magnetic field strength of each attribute region is simulated, and the theoretical magnetic field strength of each attribute region is coupled to obtain the simulation magnetic field data of the whole test crankshaft. By comparing the simulation magnetic field data obtained by simulation with the first magnetic field strength signal actually detected, the abnormal points under the simulation magnetic field data are screened out, and then the abnormal points obtained under the two conditions are compared to prove the correctness of the position of the crankshaft defect, thereby improving the accuracy of the crankshaft defect judgment.

[0076] For example, assuming that the test crankshaft is regarded as a cylinder, although the cross-sectional area of the test crankshaft in different regions is different, resulting in different resistances, the test crankshaft can be regarded as the mutual series connection between resistors with different resistances. The series connection of resistors does not have a shunt phenomenon, so the current in the magnetic powder testing method is the current value of the whole test crankshaft.

[0077] In the case where the current value and the distance (three-dimensional attribute, for example, the distance is the radius of the cylinder when the two ends of the cylinder are electrified.) are known, the magnetic field generated when the same current is applied to each region can be simulated and calculated. Since the different regions on the test crankshaft are adjacent, the calculated magnetic field strength needs to be coupled to determine the simulation magnetic field strength of the whole test crankshaft under the mutual superposition of the magnetic field. By comparing the simulation value with the actual value, the abnormal points under the simulation value are determined, and then the first abnormal signal under the clustering analysis is compared with the second abnormal signal under the simulation analysis, so as to prove the defect judgment result of the crankshaft, thereby further improving the accuracy of the crankshaft defect judgment.

[0078] In step S6, the first magnetic field strength signal is judged based on the first position information, the magnetic field strength change relationship is determined, the crack morphology is determined according to the magnetic field strength change relationship, and the real position information is obtained and output in combination with the first position information, including the following steps:

[0079] S61, based on the first position information, the first magnetic field strength signal on the corresponding position information is read and compared to determine the magnetic field strength change on the first position information;

[0080] S62, if the change in magnetic field strength in the first position information is uniform, then the crack morphology inside the crankshaft is determined to be uniform. Here, uniform morphology means that the cross-sectional areas at both ends of the two conductors divided by the crack are the same. For example, the cross-section of the original crankshaft is 3A. The cross-sectional situation of the crack division may be that the cross-sectional area of ​​conductor 1 at end a is 2A and the cross-sectional area at end b is A, and the cross-sectional area of ​​conductor 2 at end a is A and the cross-sectional area at end b is 2A. It may also be that the cross-sectional areas of conductor 1 at both ends a and b are 2A, and the cross-sectional areas of conductor 2 at both ends a and b are A. The case where the cross-sectional areas at both ends are equal (both ends a and b are 2A) is a uniform morphology.

[0081] S63, if the change in magnetic field strength in the first position information has central symmetry, then the crack morphology inside the crankshaft is determined to be symmetrical; where symmetrical morphology refers to the case where end a of wire 1 is the same as end b of wire 2, and end b of wire 1 is the same as end a of wire 2.

[0082] S64, if the change in magnetic field strength in the first position information is not regular, then the crack morphology inside the crankshaft is determined to be irregular; where irregular morphology refers to other morphologies under non-uniform and symmetrical morphologies.

[0083] S65, when the crack morphology inside the crankshaft is uniform, the first position information is output as the crack position information;

[0084] S66, when the crack morphology inside the crankshaft is symmetrical, a magnetic field is applied to the undetected orientation according to the symmetry, and the crack position of the crankshaft is determined according to the applied magnetic field to obtain the second position information. Based on the first position information and the second position information, the true position information of the crack is obtained and output.

[0085] S67, when the crack morphology inside the crankshaft is irregular, a magnetic field is applied to the undetected location based on the first positive magnetic field, and the crack location on the crankshaft is determined according to the applied magnetic field to obtain the third position information under the corresponding magnetic field. The third position information is then integrated to obtain the true location information of the crack. Specifically: the third position information obtained from the undetected location is acquired, and the third position information is integrated based on the three-dimensional properties of the test crankshaft to determine whether the third position information is the same crack, thus obtaining comprehensive position information; if the third position information is at the same position on the test crankshaft, it is determined that the third position information corresponds to the same crack, and the comprehensive position information is used as the true location information of the crack and output; if the third position information is not at the same position on the test crankshaft, it is determined that the detection is incorrect, and the third position information is re-evaluated.

[0086] In the embodiment, the variation trend of the magnetic field intensity at the first position is determined by comparing the first magnetic field intensity signals at the first position information, and then the existence of the crack in the crankshaft is determined according to the variation trend of the magnetic field intensity and the magnetic field intensity variation corresponding to different crack conditions, and the position of the crack in the crankshaft is re-determined according to different crack conditions. When the crack morphology is uniform, it indicates that the distance of the crack to the surface of the surrounding crankshaft is the same, so the corresponding real position information can be directly obtained according to the first position information. When the crack morphology is symmetrical, it indicates that the crack has symmetry on the magnetic field reaching symmetry, so the position information in a certain direction on the corresponding magnetic field is determined, and the position information that has not been obtained is re-determined, so that the final condition of the crack is clear. Similarly, when the crack morphology is irregular, it indicates that the crack morphology and the current magnetic field do not have regularity, so the position information of the crack under the current magnetic field can only be determined, and the position information does not have stereoscopic nature, so other directions of the magnetic field need to be applied to the crankshaft, and the position information is re-determined, so that the real position information of the final crack is determined, and the accuracy of the judgment result is improved.

[0087] By using the first position information, the first magnetic field intensity signals at the first position information are analyzed, so that the particularity of the crack in the current magnetic field is determined, and different position determination methods are adopted according to the particularity of the crack in the magnetic field, so that the final position of the crack determined has real reliability, and the decision-making accuracy of the decision-maker on the crankshaft is improved, and the aviation safety is ensured.

[0088] For example, after determining the location of the crack according to the positive magnetic field, the existence form of the crack is determined by the opposite negative magnetic field. Assuming that the crack exists in parallel with the current direction, the cross-sectional area of the two divided parallel resistors is equal, and the current flowing through the two divided parallel resistors does not change due to the different current directions. Therefore, the magnetic field generated has no change in size except the change in direction. Then, by comparing the sizes of the magnetic fields generated in the two directions, it is quickly determined whether the form of the crack is uniform. Similarly, when the crack is a straight line at an angle with the current direction, the size of the magnetic field is only related to the current and the distance. In the case where the distance and the current size are the same, the magnetic field strength should be the same. However, due to the different cross-sectional areas of the two divided parallel resistors, the overall distribution of the magnetic field on the two parallel resistors is not uniform, and is related to the form of the two divided parallel resistors. Therefore, when the crack is centrally symmetric with the axis of the crankshaft, the corresponding magnetic field is also centrally symmetric, that is, one side of the magnetic field at one end is high, and the other side is low. The other side of the magnetic field at the other end is low, and the other side is high. For example, the cylinder is marked as a, b two ends, and upper and lower sides. If the magnetic field strength at the upper side of the a end is 10, the magnetic field strength at the lower side of the a end is 5, and the magnetic field strength at the upper side of the b end is 5, and the magnetic field strength at the lower side of the b end is 10, it is determined that the magnetic field strength change has central symmetry in this case. Conversely, when neither of the above two special cases is met, it is determined that there is no regularity.

[0089] When it is determined that the crack form inside the crankshaft is uniform, the crack position corresponding to the first position information is the real position information of the crack.

[0090] When it is determined that the crack form inside the crankshaft is symmetric, the position information in the direction with symmetry can be determined according to the symmetry. However, the position information in the direction without symmetry needs to change the direction of the applied magnetic field and re-determine the applied magnetic field, so as to comprehensively obtain the real position information of the corresponding crack. For example, the cylinder has a, b two ends and upper, lower, front and rear four sides. When the magnetic field is applied at the ab end, the result is that the upper and lower sides are symmetric, and the front and rear sides are not symmetric. Therefore, the position relationship of the front and rear sides can be determined by applying the magnetic field on the upper and lower sides, so as to ensure that the crack inside the crankshaft can be determined.

[0091] Similarly, when the crack form inside the crankshaft has no regularity, the position information of the crack corresponding to the magnetic field is obtained by applying the magnetic field in multiple directions on the test crankshaft. The final real position information of the crack is obtained by integrating the position information of the crack. That is, when determining the spatial position information, the three-dimensional coordinates of the crack need to be determined to determine the real position information.

[0092] In step S61, based on the first position information, the first magnetic field intensity signal on the corresponding position information is read and compared to determine the magnetic field intensity change on the first position information, including the following steps:

[0093] S61a, an arbitrary position point is selected on the interval of the test crankshaft corresponding to the first position information, and the first magnetic field intensity signal is read according to the selected position point to obtain the first magnetic field sub-data under the corresponding position;

[0094] S61b, the first magnetic field sub-data is matched with each other to determine whether there are two magnetic field sub-data with equal numerical values in the first magnetic field sub-data, if it is determined that there are only two positions with the same magnetic field intensity, then the two positions are taken as the starting point, and the magnetic field intensity on the same horizontal line is compared in the direction of the current direction to determine whether the magnetic field intensity on the same horizontal line is equal;

[0095] S61c, if it is determined that the magnetic field intensity on the same horizontal line is equal, it is determined that the magnetic field intensity change on the first position information is uniform;

[0096] S61d, if it is determined that the magnetic field intensity on the same horizontal line is not equal, it is determined that the magnetic field intensity change on the first position information is not uniform, and the magnetic field intensity matching of the first magnetic field sub-data is performed, the positions with equal magnetic field intensity are marked to obtain the marked positions, and the collinear judgment of the marked positions is performed;

[0097] S61e, if it is determined that there are equal magnetic field intensities and the marked positions are collinear, it is determined that the magnetic field intensity change on the first position information is center-symmetric;

[0098] S61f, if it is determined that there are no equal magnetic field intensities or there are equal magnetic field intensities but the marked positions are not collinear, it is determined that the magnetic field change on the first position information is irregular.

[0099] For example, the test crankshaft is regarded as a cylinder, and it is assumed that the crack divides the solid cylinder into a hollow annulus. If the hollow annulus and the solid cylinder have the same center, the surface magnetic field intensity of the test crankshaft is equal, and the magnetic field intensity around the corresponding position of the annulus is equal when an arbitrary position is selected. If the hollow annulus and the solid cylinder do not have the same center, but the extension direction is horizontal (i.e., the solid cylinder is horizontally extended, and the hollow part of the hollow annulus is also horizontally extended), there are at least two positions on the hollow annulus with equal magnetic field intensity, and since the extension direction is horizontal, the magnetic field intensity on the remaining positions in the corresponding direction should also be equal.

[0100] If the extension direction of the hollow ring has a certain angle with the horizontal line, and the hollow part is assumed to form a central symmetry with the shaft center point, the corresponding magnetic field also presents central symmetry, that is, the positions with equal magnetic field intensity also present central symmetry on the test crankshaft, for example, the magnetic field intensity is 10, 9, 8, 7, 6, 5, 6, 7, 8, 9, 10, and the positions also present symmetry.

[0101] Therefore, the special magnetic field change presented according to the above special situation is used to judge the shape and position of the crack, thereby helping the decision maker to make a decision.

[0102] In step S6, the magnetic field change of the first magnetic field intensity signal is judged based on the first position information, the magnetic field intensity change relationship is determined, the crack shape is determined according to the magnetic field intensity change relationship, the real position information is obtained in combination with the first position information, and the real position information is outputted, and the following steps are further included:

[0103] S68a, the detection range of the magnetic powder detection method is obtained, the detection range of the magnetic powder detection method is compared with the real position information obtained by the judgment, and it is determined whether the real position information is in the detection range of the magnetic powder detection method;

[0104] S68b, if it is determined that the real position information is in the detection range of the magnetic powder detection method, the magnetic powder detection result is obtained, the magnetic powder detection result is compared with the real position information, if the magnetic powder detection method detects a crack at the corresponding position, the magnetic powder detection result is outputted as the final detection result;

[0105] S68c, if the magnetic powder detection method does not detect a crack at the corresponding position, it is determined that the magnetic field evaluation is wrong, and the evaluation is re-performed;

[0106] S68d, if it is determined that the real position information is not in the detection range of the magnetic powder detection method, the real position information is outputted as the final detection result.

[0107] In the embodiment, after the real position of the crack is determined, since the scheme is based on the magnetic powder detection method, the real position of the crack can be compared with the detection range of the magnetic powder detection method, so as to determine whether the magnetic powder detection method can accurately detect the position of the crack, thereby re-verifying the detected crack and ensuring the accuracy of the final judgment result. When it is determined that the magnetic powder detection method can detect the crack, the condition of the crack detected by the magnetic powder detection method is outputted, so as to ensure that the decision maker can make a correct decision. Similarly, when the magnetic powder detection method cannot detect the corresponding crack, the real position of the crack obtained by the magnetic field change judgment is outputted, thereby improving the decision accuracy.

[0108] For example, if the magnetic powder detection result is a surface crack with a depth less than 3 mm, and the actual judgment result is also a crack with a depth less than 3 mm, it indicates that the magnetic powder detection method can correctly detect the crack, thereby achieving the purpose of verifying the position information of the actual crack obtained by judgment, and improving the accuracy of judgment. If the actual judgment result is a crack with a depth less than 3 mm, the magnetic powder detection method cannot correctly detect the crack, so it cannot verify the position information, and the position information of the actual crack obtained by judgment is directly output.

[0109] Compared with the existing aviation nondestructive testing method for evaluating the uniformity of the surface magnetization field of the crankshaft, the application improves the accuracy of the crankshaft defect judgment.

[0110] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, therefore: any equivalent changes made on the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A method for evaluating the uniformity of the surface magnetization field of a crankshaft for aviation non-destructive testing, characterized by, The method comprises the following steps: Step S1, before detecting the crankshaft to be tested, pre-treatment is performed on the crankshaft to be tested to obtain a test crankshaft, a positive magnetic field is applied to the crankshaft according to a magnetic powder detection method, the magnetic field strength of the applied magnetic field is collected, and a first magnetic field strength signal is obtained; Step S2, the three-dimensional properties of the test crankshaft are obtained, the crankshaft is divided according to the three-dimensional properties, the same attribute region is obtained, and the first magnetic field strength signal on the same attribute region is analyzed to determine the abnormal signal existing in the first magnetic field strength signal; Step S3, based on the abnormal information, the theoretical magnetic field strength where the abnormal information is located is determined, and the theoretical magnetic field strength is compared with the first magnetic field strength signal to determine the magnetic field strength difference value; Step S4, based on the magnetic field characteristics of the conductor, the current difference value in the magnetic field strength difference state is determined, the current data in the magnetic powder detection method is combined with the current difference value to determine the shunt condition caused by the crack, and shunt data is obtained; Step S5, based on the shunt data and the three-dimensional properties of the corresponding region, the position of the crack is determined, and first position information is obtained; Step S6, based on the first position information, the magnetic field change of the first magnetic field strength signal is judged, the magnetic field strength change relationship is determined, the crack morphology is determined according to the magnetic field strength change relationship, the real position information is obtained by combining the first position information, and the real position information is output.

2. The method for evaluating the uniformity of the surface magnetizing field of a crankshaft for aviation non-destructive testing according to claim 1, characterized in that: Step S1, comprising: according to the application direction of the applied positive magnetic field, the magnetic field strength of the remaining space of the crankshaft is collected by using a Hall sensor to obtain magnetic field data with direction, and the magnetic field data with direction is marked as the first magnetic field strength signal.

3. The method of claim 2, wherein the method further comprises: determining the magnetic field uniformity of the surface magnetization of the crankshaft. Step S2, comprising: Based on the three-dimensional properties of the test crankshaft, the test crankshaft is divided to obtain the same attribute region under the same three-dimensional properties, the first magnetic field strength signal on the same attribute region is statistically analyzed to obtain the magnetic field fluctuation range of each same attribute region; According to the magnetic field fluctuation range of the same attribute region, the first abnormal signal is determined by screening the first magnetic field strength signal, and the first abnormal signal corresponding to the detection range of the Hall sensor is determined.

4. The method of claim 3, wherein the method further comprises: Step S2, further comprising: Obtain the current data in the magnetic powder detection method, and simulate the theoretical magnetic field strength of each same attribute region according to the current data to obtain the theoretical magnetic field strength on each same attribute region; According to the positional relationship between each same attribute region, the theoretical magnetic field strength is coupled to obtain simulation magnetic field data; The simulation magnetic field data is compared with the actually detected first magnetic field strength signal to determine the abnormal points existing in the first magnetic field strength signal compared with the simulation magnetic field data, and the second abnormal signal is obtained; The second abnormal signal is marked with the position of the test crankshaft to obtain a second crankshaft range; The second crankshaft range is compared with the first crankshaft range corresponding to the first abnormal signal, if the second crankshaft range is the same as the first crankshaft range, it is determined that the crankshaft range has defects; If the second crankshaft range is different from the first crankshaft range, it is determined that the first crankshaft range and the second crankshaft range do not have defects.

5. The method of evaluating the uniformity of the surface magnetization field of a crankshaft for aviation non-destructive testing according to claim 1, characterized in that: Step S6, comprising: Step S61, reading and comparing the first magnetic field intensity signal on the corresponding position information based on the first position information to determine the magnetic field intensity change on the first position information; Step S62, if the magnetic field intensity change on the first position information is uniform, it is determined that the crack pattern inside the crankshaft is uniform; Step S63, if the magnetic field intensity change on the first position information has central symmetry, it is determined that the crack pattern inside the crankshaft is symmetric; Step S64, if the magnetic field intensity change on the first position information has no regularity, it is determined that the crack pattern inside the crankshaft is irregular; Step S65, when the crack pattern inside the crankshaft is uniform, the first position information is output as the position information of the crack; Step S66, when the crack pattern inside the crankshaft is symmetric, a magnetic field is applied to the undetected direction according to the symmetry, and the crack position of the crankshaft is judged according to the applied magnetic field to obtain second position information, and the real position information of the crack is obtained based on the first position information and the second position information and output; Step S67, when the crack pattern inside the crankshaft is irregular, a magnetic field is applied to the undetected direction according to the first forward magnetic field, and the crack position of the crankshaft is judged according to the applied magnetic field to obtain third position information under the corresponding magnetic field, and the third position information is integrated to obtain the real position information of the crack.

6. The method for evaluating the uniformity of the surface magnetizing field of a crankshaft for aviation non-destructive testing according to claim 5, characterized in that: Step S61 includes: Selecting an arbitrary position point on the interval of the test crankshaft corresponding to the first position information, and reading the first magnetic field intensity signal according to the selected position point to obtain first magnetic field sub-data under the corresponding position; Match the first magnetic field sub-data with each other to determine whether there are two magnetic field sub-data with equal numerical values, if it is determined that there are only two positions with the same magnetic field intensity, then take the two positions as the starting point, take the current direction as the direction, compare the magnetic field intensity on the same horizontal line to determine whether the magnetic field intensity on the same horizontal line is equal; If it is determined that the magnetic field intensity on the same horizontal line is equal, it is determined that the magnetic field intensity change on the first position information is uniform; If it is determined that the magnetic field intensity on the same horizontal line is not equal, it is determined that the magnetic field intensity change on the first position information is not uniform, and the magnetic field intensity of the first magnetic field sub-data is matched, the positions with equal magnetic field intensity are marked to obtain marked positions, and the collinear judgment of the marked positions is performed; If it is determined that there are equal magnetic field intensities and the marked positions are collinear, it is determined that the magnetic field intensity change on the first position information is central symmetric; If it is determined that there is no equal magnetic field intensity or there is equal magnetic field intensity but the marked positions are not collinear, it is determined that the magnetic field change on the first position information is irregular.

7. The method of claim 5, wherein the method further comprises: determining the magnetic field uniformity of the surface magnetization of the crankshaft. Step S6 further includes: Obtain the detection range of the magnetic powder detection method, compare the detection range of the magnetic powder detection method with the real position information obtained by judgment to determine whether the real position information is within the detection range of the magnetic powder detection method; If it is determined that the test range of the magnetic particle detection method is reached, the magnetic particle detection result is obtained and compared with the true position information. If the magnetic particle detection method detects a crack at the corresponding position, the magnetic particle detection result is output as the final detection result. If the magnetic particle detection method does not detect a crack at the corresponding position, it is determined that the magnetic field evaluation is wrong, and the evaluation is re-performed. If it is determined that the test range of the magnetic particle detection method is not reached, the true position information is output as the final detection result.

8. The method of claim 6, wherein the method further comprises: determining the magnetic field uniformity of the surface magnetization of the crankshaft. Step S67 comprises: The third position information determined at the undetected orientation is obtained, and the third position information is integrated based on the three-dimensional attribute of the test crankshaft to determine whether the third position information is the same crack, and comprehensive position information is obtained. If the third position information is at the same position of the test crankshaft, it is determined that the third position information corresponds to the same crack, and the comprehensive position information is output as the true position information of the crack. If the third position information is not at the same position of the test crankshaft, it is determined that the detection is wrong, and the third position information is re-determined.

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