CN111521309B - Method and system for determining residual stress and residual elimination effect of material - Google Patents

Abstract

The invention provides a method and a system for determining residual stress and residual elimination effect of a material, wherein the method comprises the following steps: arranging a plurality of measured points on the surface of a measured component according to a preset interval; exciting ultrasonic waves in the circumferential direction of each measured point through an ultrasonic generator, and acquiring the distribution of the acoustic time difference of critical refraction longitudinal waves formed on the surface of the measured component in the circumferential direction of the measured point; and determining the main direction of the residual stress of the surface of the material according to the distribution of the sound time difference of each critical refraction longitudinal wave, and further determining the residual stress of the tested component. On the one hand, the material can not be damaged, the body of a tester can not be damaged, and on the other hand, the main direction of the residual stress of each tested point can be represented, so that the residual stress of the material can be more accurately measured compared with the current one-way residual stress of one or a few points, and the residual stress eliminating effect of the material can be accurately determined.

Description

Method and system for determining residual stress and residual effect of materials

technical field

The invention relates to the technical field of stress detection, and more particularly, to a method and system for determining residual stress and residual effect of materials.

Background technique

For materials widely used in engineering, the material components will be affected and influenced by various processes and other factors during the manufacturing process; when these factors disappear, if the above-mentioned effects and influences on the material components cannot be completely disappeared. , there are still some actions and influences remaining in the component, then this residual action and influence is called residual stress or residual stress. Excessive residual stress will lead to a serious decline in the local performance of the component, and for important load-bearing components, once it fails, it will cause major economic losses or accidents. At present, the residual stress is still measured in the same way as the principal stress of the material, such as using the drilled strain gage method or X-ray diffraction method. When testing the strain gage method, it is necessary to use an adhesive to stick the strain gage to the test. On the surface of the material, drilling small holes in the attachment of the strain gauge is a very inconvenient and destructive method. X-ray diffraction method is based on elasticity and lattice diffraction theory, which can measure stress more accurately, but X-ray radiation is harmful to the body, and the equipment is bulky, which is very inconvenient to measure. At present, for welded parts, vibration aging method or heat treatment is often used to eliminate residual stress. Due to the uncertainty of the concentration position of residual stress, the determination of the residual stress requires efficient large-area inspection of the tested part. The existing materials There are many limitations in the method of determining residual stress. Therefore, a new technique for determining residual stress of materials is urgently needed.

SUMMARY OF THE INVENTION

The present invention provides a method and system for determining residual stress and residual effect of materials, so as to provide at least a new and precise technical method for determining residual stress residual stress of materials. In the determination method and system provided by the present invention, a plurality of measured points are set on the surface of the measured component according to a preset interval; ultrasonic waves are excited in the circumferential direction of each measured point by an ultrasonic generator, and the ultrasonic waves formed on the surface of the measured component are obtained. The distribution of the acoustic time difference of the critical refracted longitudinal wave in the circumferential direction of the measured point; according to the distribution of the acoustic time difference of each critical refracted longitudinal wave, the main direction of the residual stress on the material surface is determined, and then the residual stress of the measured component is determined. On the one hand, it will not damage the material itself, nor will it cause harm to the body of the tester. On the other hand, because the main direction of residual stress of each measured point can be characterized, compared with the current single-point measurement method by measuring one or very few points. The directional residual stress can more accurately measure the residual stress of the material, and can accurately determine the residual stress elimination effect of the material.

In certain embodiments, a method for determining residual stress in a material, comprising:

Set multiple points to be measured on the surface of the component to be measured according to preset intervals;

The ultrasonic generator is used to excite ultrasonic waves in the circumferential direction of each measured point, and the distribution of the acoustic time difference of the critically refracted longitudinal wave formed on the surface of the measured component in the circumferential direction of the measured point is obtained;

The residual stress of the tested component is determined according to the distribution of the acoustic transit time of each critical refracted longitudinal wave.

In some embodiments, the ultrasonic generator is used to excite ultrasonic waves in the circumferential direction of each measured point to obtain the distribution of the acoustic time difference of the critically refracted longitudinal wave formed on the surface of the measured component in the circumferential direction of the measured point, including: :

The ultrasonic wave is excited in the circumferential direction of each measured point by the ultrasonic generator;

The ultrasonic generator is rotated around the measured point, and the formed critical refraction longitudinal wave is received by an ultrasonic receiver that is opposite to the ultrasonic generator and rotates synchronously with the ultrasonic generator;

According to the time length of the critical refracted longitudinal wave received at each angle of the circumference of the measured point, the distribution of the acoustic time difference of the critical refracted longitudinal wave corresponding to the measured point is determined.

In some embodiments, determining the residual stress of the component under test according to the distribution of each critical refracted longitudinal wave acoustic time difference includes:

According to the distribution of each critical refraction longitudinal wave acoustic time difference, determine the one-to-one corresponding critical refraction longitudinal wave acoustic time difference distribution curve for each measured point;

Determine the residual stress of the component under test according to each critical refracted longitudinal wave acoustic transit time distribution curve.

In some embodiments, the determining the residual stress of the component under test according to each critical refraction longitudinal wave acoustic transit time distribution curve includes:

According to the distribution curve of each critical refraction longitudinal wave acoustic time difference, the maximum value of the critical refraction longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value are obtained;

The residual stress of the measured component is determined according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value.

In some embodiments, determining the residual stress of the measured component according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value, including:

Determine the residual stress distribution of the measured component according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point;

Determine the variation trend of the residual stress direction of the tested component according to each angle corresponding to the maximum value;

The residual stress of the tested component is determined according to the residual stress distribution and the change trend of the residual stress direction.

In some embodiments, determining the residual stress distribution of the component under test according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point includes:

Based on the preset correspondence between the critical refraction longitudinal wave acoustic time difference and the gray value, determine the gray value corresponding to the maximum value of the critical refraction longitudinal wave acoustic time difference of each measured point;

According to each grayscale value, the residual stress distribution of the tested part displayed in grayscale is determined.

In some embodiments, determining the variation trend of the residual stress direction of the component under test according to each angle corresponding to the maximum value includes:

Based on the preset correspondence between the angle and the curvature, and according to the angle corresponding to the maximum value of each measured point, determine the direction curve corresponding to each measured point one-to-one;

Fit each direction curve to a network curve set, and determine the variation trend of the residual stress direction of the component under test according to the fitted network curve set.

In some embodiments, a plurality of measured points are set on the surface of the component to be measured according to preset intervals, including:

Divide the surface of the component under test into a grid array;

The center of each grid in the grid array is set to the measured point.

In certain embodiments, a method for determining the effect of eliminating residual stress in a material includes:

Use the method for determining residual stress as described above to determine the residual stress of the component under test after elimination;

The annihilation effect of the tested part is determined based on the residual stress of the tested part after annihilation.

In certain embodiments, a system for determining residual stress in a material includes:

The measured point setting module, which sets multiple measured points on the surface of the measured part according to the preset spacing;

The acquisition module excites ultrasonic waves in the circumferential direction of each measured point through the ultrasonic generator, and obtains the distribution of the acoustic time difference of the critical refracted longitudinal wave formed on the surface of the measured component in the circumferential direction of the measured point;

The determination module determines the residual stress of the tested component according to the distribution of the acoustic time difference of each critical refracted longitudinal wave.

In some embodiments, the obtaining module includes:

The ultrasonic excitation unit excites ultrasonic waves in the circumferential direction of each measured point through the ultrasonic generator;

Rotating the recording unit, the ultrasonic generator is rotated around the measured point, and the critical refracted longitudinal wave formed is received by an ultrasonic receiver that is opposite to the ultrasonic generator and rotates synchronously with the ultrasonic generator;

The critical refracted longitudinal wave acoustic time difference distribution determining unit determines the distribution of the critical refracted longitudinal wave acoustic time difference corresponding to the measured point according to the time duration of the critical refracted longitudinal wave received at each angle in the circumferential direction of the measured point.

In some embodiments, the determining module includes:

The acoustic time difference distribution curve determination unit determines the critical refraction longitudinal wave acoustic time difference distribution curve corresponding to each measured point according to the distribution of each critical refraction longitudinal wave acoustic time difference;

The acoustic transit time distribution curve is based on the unit, and the residual stress of the tested component is determined according to each critical refraction longitudinal wave acoustic transit time distribution curve.

In some embodiments, the acoustic time difference distribution curve according unit includes:

The maximum value search unit, according to the distribution curve of each critical refracted longitudinal wave acoustic time difference, to obtain the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value;

The maximum value is based on the unit, and the residual stress of the tested component is determined according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value.

In some embodiments, the maximum value basis unit includes:

The residual stress distribution determination unit determines the residual stress distribution of the measured component according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point;

The unit for determining the change trend of the residual stress direction, according to each angle corresponding to the maximum value, to determine the change trend of the residual stress direction of the tested component;

The residual stress determination unit determines the residual stress of the tested component according to the residual stress distribution and the change trend of the residual stress direction.

In some embodiments, the residual stress distribution determination unit includes:

The gray value corresponding unit determines the gray value corresponding to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point based on the preset corresponding relationship between the critical refracted longitudinal wave acoustic time difference and the gray value;

The distribution determining unit determines, according to each grayscale value, the residual stress distribution of the component under test displayed in grayscale.

In some embodiments, the residual stress direction change trend determination unit includes:

The curvature correspondence unit, based on the preset corresponding relationship between the angle and the curvature, determines the direction curve corresponding to each measured point one-to-one according to the angle corresponding to the maximum value of each measured point;

The direction change trend determination unit fits each direction curve into a network curve set, and determines the direction change trend of residual stress of the tested component according to the fitted network curve set.

In some embodiments, the measured point setting module includes:

The grid array setting unit divides the surface of the tested part to form a grid array;

The measured point setting unit, which sets the center of each grid in the grid array as the measured point.

In certain embodiments, a system for determining the effect of residual stress in a material, comprising:

The residual stress determination module after elimination is used to determine the residual stress of the tested component after elimination by using the residual stress determination method as described above;

The elimination effect determination module determines the elimination effect of the tested component based on the residual stress of the tested component after elimination.

In some embodiments, an electronic device includes a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the following steps when executing the program:

Determine the residual stress of the tested component according to the distribution of the acoustic time difference of each critical refracted longitudinal wave;

The annihilation effect of the tested part is determined based on the residual stress of the tested part after annihilation.

In some embodiments, a computer-readable storage medium having a computer program stored thereon, the computer program implements the following steps when executed by a processor:

Determine the residual stress of the tested component according to the distribution of the acoustic time difference of each critical refracted longitudinal wave;

The annihilation effect of the tested part is determined based on the residual stress of the tested part after annihilation.

The beneficial effects of the present invention

The method and system for determining the residual stress and the residual effect of the material provided by the present invention, by setting a plurality of measured points on the surface of the measured part, and exciting ultrasonic waves to each of the measured points one by one, and then obtain the formation of the measured parts on the surface of the measured part. The distribution of the acoustic time difference of the critical refracted longitudinal wave in the circumferential direction of the measured point determines the residual stress of the measured component. Compared with the current measurement of one or very few points, the residual stress of the measured point can be measured more accurately. The practice shows that the residual stress after elimination can also be accurately measured and characterized, and the effect is obvious. , and then can accurately determine the residual stress relief effect of the material.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

FIG. 1 shows one of the structural schematic diagrams of the residual stress measuring device suitable for realizing the embodiment of the present invention.

FIG. 2 shows the second structural schematic diagram of a residual stress measuring device suitable for realizing the embodiment of the present invention.

FIG. 3 shows a critical refraction longitudinal wave acoustic transit time-angle distribution curve in a stress-free state in an embodiment of the present invention.

FIG. 4 shows the acoustic transit time-angle distribution curve of critical refraction longitudinal waves with residual stress in an embodiment of the present invention.

FIG. 5 shows a schematic flowchart of a method for determining residual stress of a material in an embodiment of the present invention.

FIG. 6 shows a schematic diagram of a specific flow of step S1 in FIG. 5 in an embodiment of the present invention.

FIG. 7 shows a schematic diagram of a specific flow of step S2 in FIG. 5 in an embodiment of the present invention.

FIG. 8 shows a schematic flowchart of a specific flow of step S3 in FIG. 5 in an embodiment of the present invention.

FIG. 9 is a schematic diagram showing a specific flow of step S32 in FIG. 8 in an embodiment of the present invention.

FIG. 10 shows a schematic flowchart of a specific flow of step S322 in FIG. 9 in an embodiment of the present invention.

FIG. 11 shows a schematic structural diagram of a residual stress distribution mapping model in an embodiment of the present invention.

FIG. 12 shows a schematic diagram of a specific flow of step S322a in FIG. 10 in an embodiment of the present invention.

FIG. 13 shows a schematic diagram of the corresponding model of the critical refraction longitudinal wave acoustic time difference and the gray value in the embodiment of the present invention.

FIG. 14 shows a schematic diagram of a specific flow of step S322b in FIG. 10 in an embodiment of the present invention.

FIG. 15 shows a schematic diagram of a network curve set representing the corresponding relationship between the angle corresponding to the maximum value and the curvature in an embodiment of the present invention.

FIG. 16 shows one of the schematic flowcharts of the method for determining the residual stress elimination effect of the material in the embodiment of the present invention.

FIG. 17 shows the second schematic flow chart of the method for determining the residual stress elimination effect of the material in the embodiment of the present invention.

FIG. 18 shows a schematic structural diagram of a system for determining residual stress in an embodiment of the present invention.

FIG. 19 shows a schematic diagram of a specific structure of the measured point setting module 100 in FIG. 18 in an embodiment of the present invention.

FIG. 20 shows a schematic diagram of a specific structure of the acquisition module 200 in FIG. 18 in an embodiment of the present invention.

FIG. 21 shows a schematic diagram of a specific structure of the determination module 300 in FIG. 18 in an embodiment of the present invention.

FIG. 22 shows a schematic diagram of a specific structure of the acoustic time difference distribution curve base unit 302 in FIG. 21 according to an embodiment of the present invention.

FIG. 23 shows a schematic diagram of a specific structure of the maximum value dependent unit 302b in FIG. 22 in an embodiment of the present invention.

FIG. 24 shows a schematic diagram of a specific structure of the residual stress distribution determination unit 302b-1 in FIG. 23 in an embodiment of the present invention.

FIG. 25 shows a schematic flowchart of a specific flow of the residual stress direction change trend determination unit 302b-2 in FIG. 23 in an embodiment of the present invention.

FIG. 26 shows a schematic structural diagram of a system for determining the effect of eliminating residual stress of materials in an embodiment of the present invention.

FIG. 27 shows a schematic structural diagram of an electronic device suitable for implementing the embodiments of the present application.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

At present, the measurement of residual stress mainly adopts the same method as the measurement of material principal stress, but the material principal stress is relatively large, and the change and distribution trend are more obvious. Therefore, the current method can accurately measure the material principal stress. However, the residual stress of the material is small, and the change and distribution trend are not obvious. Therefore, the current method of measuring principal stress cannot be fully applied to the measurement of residual stress, especially the residual stress after elimination.

For materials widely used in engineering, the stress on the material will cause the change of the ultrasonic sound speed, so the ultrasonic sound speed can be used to evaluate the material stress and residual stress. Considering the low accuracy of the residual stress of the material measured by the method of measuring the principal stress of the material, the limitations of the measurement method itself, and the inability to effectively measure the residual stress after elimination. The present application provides a method and system for determining residual stress of a material, a method and system for determining the residual stress relief effect of a material, an electronic device and a computer storage medium for implementing the determination method. First, set a plurality of points to be measured on the surface of the component to be measured at preset intervals; then use the ultrasonic generator to excite ultrasonic waves in the circumferential direction of each point to be measured, and obtain the acoustic time difference of the critical refracted longitudinal wave formed on the surface of the component to be measured. The distribution of the measured point in the circumferential direction; finally, the residual stress of the measured component is determined according to the distribution of the acoustic time difference of each critical refracted longitudinal wave. In addition, the method for determining the elimination effect of the material determines the elimination effect by comparing the isotropic or anisotropic residual stress after elimination and the residual stress in the initial environment of the material. On the one hand, it will not damage the material itself, nor will it cause harm to the body of the tester. On the other hand, it can not only accurately measure the residual stress of the material, but also accurately measure the residual stress after elimination, and then accurately determine the residual stress of the material. Removal effect.

In a specific residual stress measurement scenario, the present application uses a residual stress measurement device to implement the residual stress determination method of the present invention, see FIG. 1 and FIG. 2 , the device includes an ultrasonic generator 1, an ultrasonic receiver 2, an ultrasonic generator Both the device 1 and the ultrasonic receiver 2 include an ultrasonic transducer 3 and an acoustic wedge 4. The inclination angles of the two acoustic wedges are set symmetrically. θ, and then according to Snell's law, when the ultrasonic wave is excited in the ultrasonic transmitter 1, a critical refracted longitudinal wave will be generated on the near surface of the measured object, which will be received by the ultrasonic receiver 2, so that the ultrasonic generator 1 and the ultrasonic wave can be rotated synchronously. The receiver 2 further determines the distribution of the acoustic time difference of the critical refracted longitudinal wave corresponding to the measured point according to the duration of the critical refracted longitudinal wave received at each angle in the circumferential direction of the measured point. According to the distribution, the critical refraction longitudinal wave acoustic time difference-angle distribution curve is determined (Fig. 3-Fig. 4 are the critical refraction longitudinal wave acoustic time difference-angle distribution curves in two different states).

It can be understood that when the tested part is not industrially processed, a certain point on the tested surface is in a stress-free state, as shown in the critical refraction longitudinal wave acoustic transit time-angle distribution curve in the stress-free state in Fig. 3. When the ultrasonic wave is divided, the acoustic transit time distribution of the critical refracted longitudinal wave on the measured surface is uniform. When the material undergoes uneven and anisotropic deformation during welding, as shown in the example of the critical refraction longitudinal wave acoustic transit time-angle distribution curve with residual stress in Fig. 4, it will lead to Ultrasonic sound time difference is different.

It can be known that, through the above device, the distribution of the acoustic time difference of the critical refracted longitudinal wave of each measured point in the circumferential direction of the measured point can be measured. In the method for determining the residual stress of the material provided by the first aspect of the present invention, as shown in FIG. 5 , the method specifically includes:

S1: Set multiple points to be measured on the surface of the component to be measured according to preset intervals.

S2: Excite ultrasonic waves in the circumferential direction of each measured point through the ultrasonic generator, and obtain the distribution of the acoustic time difference of the critically refracted longitudinal wave formed on the surface of the measured component in the circumferential direction of the measured point;

S3: Determine the residual stress of the tested component according to the distribution of the acoustic time difference of each critical refracted longitudinal wave.

In order to ensure the uniform setting of the measured points, so as to avoid the problem of large errors caused by the unevenness of the measured points, the more the measured points, the smaller the error, but due to the limitation of the measuring device, the number of measured points is limited, and the measured points can be evenly arranged at this time.

In a specific embodiment, the acoustic time difference is measured by the following method:

If the ultrasonic propagation time t ₀ corresponding to the zero stress σ ₀ of the material is measured and the ultrasonic propagation time t corresponding to the measured stress σ, then σ-σ ₀ =L(tt ₀ ) or △σ=L△t;

Δt is the variation difference of ultrasonic propagation time (acoustic time difference), Δt=tt ₀ ;

△σ is the residual stress variation, △σ=σ-σ ₀ ;

L is a constant, calibrated according to the actual detection.

In a specific embodiment, as shown in FIG. 6 , step S1 specifically includes:

S11: Divide the surface of the component under test to form a grid array;

S12: Set the center of each grid in the grid array as the measured point.

In this embodiment, since the surface of the component under test forms a grid array, the center of each grid is the point to be measured, so that the distances between the points to be measured are the same, thereby achieving the purpose of average setting.

It can be known from the aforementioned measurement device that, as shown in FIG. 7 , step S2 specifically includes:

S21: Excite ultrasonic waves in the circumferential direction of each measured point through an ultrasonic generator.

S22: the ultrasonic generator is rotated with the measured point as the center, and the critical refraction longitudinal wave formed is received by the ultrasonic receiver set opposite to the ultrasonic generator and rotated synchronously with the ultrasonic generator;

S23: Determine the distribution of the acoustic time difference of the critical refracted longitudinal wave corresponding to the measured point according to the duration of the critical refracted longitudinal wave received at each angle in the circumferential direction of the measured point.

In this embodiment, the stress sensor is the aforementioned measuring device. For each measured point, the ultrasonic generator 1 and the ultrasonic receiver 2 can be rotated synchronously, and then according to the critical value received at each circumferential angle of the measured point The duration of the refracted longitudinal wave determines the distribution of the critical refracted longitudinal wave acoustic time difference corresponding to the measured point. Correspondingly, graphs similar to Figures 3-4 are obtained.

Referring to Figure 8, that is, S3 specifically includes:

S31: according to the distribution of each critical refraction longitudinal wave acoustic time difference, determine the critical refraction longitudinal wave acoustic time difference distribution curve corresponding to each measured point one-to-one;

S32: Determine the residual stress of the tested component according to each critical refraction longitudinal wave acoustic transit time distribution curve.

After obtaining the critical refraction longitudinal wave acoustic time difference distribution curve of each measured point, it is necessary to find the maximum value on the curve and the angle corresponding to the maximum value. The stronger the acoustic time difference, the greater the stress on the material. Then the maximum value corresponds to the maximum stress value of the point in the angle. Further, the residual stress of the entire tested component can be determined according to the maximum stress value and the corresponding angle.

Obviously, those skilled in the art understand that, as shown in Figure 9, step S32 includes:

S321: Obtain the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value according to the distribution curve of each critical refracted longitudinal wave acoustic time difference.

S322: Determine the residual stress of the measured component according to the maximum value of the critical refraction longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value.

Further, during specific implementation, referring to FIG. 10 , the steps of the above S322 specifically include:

S322a: Determine the residual stress distribution of the measured component according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point;

S322b: Determine the variation trend of the residual stress direction of the tested component according to each angle corresponding to the maximum value;

S322c: Determine the residual stress of the tested component according to the residual stress distribution and the change trend of the residual stress direction.

Two pieces of information can be obtained according to the maximum value and the corresponding angle. The maximum value can be used to determine the residual stress distribution of the component under test, which is equivalent to ignoring the residual stress in the remaining directions. The most significant stress of each measured point is taken as the "represent". Then, the residual stress distribution of the measured component is determined according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point. In addition, the change trend of the residual stress direction of the component under test can be determined according to the corresponding angle, so that the residual stress of the complete component under test can be determined by combining the two.

The following is a detailed description of how to obtain the residual stress distribution and the change trend of the residual stress direction.

In some alternative embodiments, the residual stress distribution may be mapped to a visible or identifiable image, a post-curve model, or the like. For example, referring to Fig. 11, it can be known that the residual stress distribution can be mapped into a three-dimensional model represented by a peak value through a certain mapping relationship. In the three-dimensional model, the height represents the magnitude of the residual stress, and the height of each measured point is different, and then The formation of "mountain peaks" of different heights.

As shown in Figure 11, the residual stress is measured in the area of 100mm×100mm, and it can be found that the residual stress in the central area is the largest.

Or, in order to show the residual stress distribution of the tested part more concretely and vividly, it can be mapped to a shape-independent variable, which can be directly reflected on the tested part, which is more vivid and clear. In this embodiment, as shown in FIG. 12 , step S322a specifically includes:

S322a-1: Based on the preset correspondence between the critical refraction longitudinal wave acoustic time difference and the gray value, determine the gray value corresponding to the maximum value of the critical refraction longitudinal wave acoustic time difference of each measured point.

S322a-2: Determine the residual stress distribution of the component under test displayed in grayscale according to each grayscale value.

It can be known from FIG. 13 that the preset corresponding relationship between the critical refraction longitudinal wave acoustic time difference and the gray value may be a gray value mapping of the color corresponding to the critical refraction longitudinal wave acoustic time difference. In one embodiment, the preset corresponding relationship between the critical refraction longitudinal wave acoustic time difference and the gray value is a gray scale model as shown in FIG. 13 . For the sake of clarity, the gray value in the figure is from black to hundred. The range is generally from 0 to 255, with 255 for white and 0 for black. The black corresponds to 200Mpa, and the white corresponds to 400Mpa, as shown in Figure 13.

It can be seen from Figure 13 that the intensity values A-B (linearly increasing), corresponding to black-to-white changes. In this way, through the grayscale correspondence, the grayscale value Ci corresponding to each intensity value can be obtained, so that the residual stress distribution can be determined by the grayscale change on the measured component.

Further, in some embodiments, in order to better reflect the change trend of the residual stress direction, the trend may be expressed in the form of a network curve. Referring to FIG. 14 , step S322b specifically includes:

S322b-1: Based on the preset corresponding relationship between the angle and the curvature, and according to the angle corresponding to the maximum value of each measured point, determine a direction curve corresponding to each measured point one-to-one.

S322b-2: Fit each direction curve to a network curve set, and determine the variation trend of the residual stress direction of the component under test according to the fitted network curve set.

The network curve set is shown in Figure 15. In this figure, the angle corresponding to the maximum value of each measured point is converted into a curve with different curvatures according to the preset corresponding relationship between the angle and the curvature. Since the distribution of stress has a trend , the angle difference between the adjacent measured points and the maximum value is small. Therefore, each curve can be fitted and connected to form a network curve set, and the measured value can be determined according to the density and curvature distribution of the fitted network curve set. Variation trend of residual stress direction of components.

In some embodiments, the structure mapped to the gray value can be combined with the network curve set in a characterization model, so that the residual stress distribution expressed by the gray value and the trend expressed by the network curve set can be simultaneously integrated. Comprehensive situation of residual stress.

Of course, in other embodiments, the color value can be used instead of the above gray value, and the color value distribution can be obtained to express the residual stress distribution. The residual stress distribution expressed by the gray value is only expressed in grayscale, and the calculation is simple. The color value of the three primary colors The expression of residual stress distribution needs to be represented by three colors, which is more complex, but more comprehensive, and can be set in combination with specific actual conditions, and the present invention is not limited to this.

Obviously, it can be known from the detailed description of the above-mentioned embodiments of the method for determining residual stress of materials that the method for determining residual stress of materials of the present application is to set a plurality of measured points on the surface of the component to be measured, and excite each measured point one by one. Ultrasonic wave, and then obtain the distribution of the acoustic time difference of the critical refracted longitudinal wave formed on the surface of the tested component in the circumferential direction of the measured point to determine the residual stress of the measured component. On the other hand, because the residual stress of each measured point can be characterized, the residual stress of the material can be measured more accurately than the current measurement of one or very few points. Stress can also be accurately measured and characterized, with significant results.

Based on the above method for determining residual stress, the present application also provides a method for determining the effect of eliminating residual stress of isotropic materials. As shown in Figure 16, it specifically includes:

S41: use the residual stress determination method as above to determine the residual stress of the tested component after elimination;

S42: Determine the elimination effect of the tested component according to the residual stress of the tested component after elimination.

According to the characteristics of the aforementioned isotropic materials, it can be known that, in the case of no stress, the critical refraction longitudinal wave acoustic transit time-angle distribution curve of the tested component is shown in Figure 3. Since the external environment such as temperature and pressure makes the stress generated by the component under test too small compared with the stress generated by welding and other processes, it can be ignored. Therefore, it can be assumed that the critical refraction longitudinal wave acoustic transit time-angle distribution curve is shown in Fig. 3. In this way, by comparing the critical refraction longitudinal wave acoustic time difference-angle distribution curve of the measured component after elimination with the distribution curve in Fig. 3, we can know the residual stress of each measured point after elimination, and then know the entire measured point. The annihilation effect of the part.

Based on the same reason, the present application also provides a method for determining the residual stress elimination effect of anisotropic materials, which is the same as the above-mentioned method for determining residual stress in the present application, but the difference is that the anisotropic material does not When performing welding and other process operations, due to the effect of anisotropy, the stress generated by the influence of the same external environment is different. If it is ignored, the error will be large, so it needs to be compared and verified.

In this embodiment, a method for determining the effect of eliminating residual stress of anisotropic materials is provided. As shown in Figure 17, it specifically includes:

S51: Use the residual stress determination method as described above to determine the residual stress of the tested component before and after elimination.

S52: Determine the elimination effect of the tested component by comparing the residual stress of the tested component before and after elimination.

That is, in this embodiment, the above method needs to be used to determine the residual stress before and after elimination, and then the elimination effect is determined by comparing the residual stress of the tested component before and after elimination.

From the above examples of isotropic and anisotropic materials, it can be known that the present application can accurately detect the residual effect of isotropic and anisotropic components under test, which solves the current lack of detection of residual effect. technical issues and obstacles.

Further, based on the same technical concept as above, the present application also provides a residual stress determination system, as shown in FIG.

In a specific embodiment, the measured point setting module 100 is a device with a marking function such as a marker pen, which can mark and divide the measured component, thereby marking the measured point and grid array. The measured point setting module 100 sets a plurality of measured points on the surface of the measured component according to a preset interval.

Preferably, in order to ensure the uniform setting of the measured points, so as to avoid the problem of large errors caused by the unevenness of the measured points, the more the measured points, the smaller the error, but in view of the limitation of the measuring device, the measured The number of points is limited, and the measured points can be arranged evenly at this time. As shown in Figure 19, the measured point setting module 100 includes:

The grid array setting unit 101 divides the surface of the component under test to form a grid array;

The measured point setting unit 102 sets the center of each grid in the grid array as the measured point.

In this embodiment, since the surface of the component under test forms a grid array, the center of each grid is the point to be measured, so that the distances between the points to be measured are the same, thereby achieving the purpose of average setting.

In a specific embodiment, as shown in FIG. 20 , the acquisition module 200 includes an ultrasonic excitation unit 201 , a rotation recording unit 202 and a critical refraction longitudinal wave acoustic time difference distribution determining unit 203 . The ultrasonic excitation unit is the above-mentioned measuring device, and the rotation recording unit can be any recording device with a recording function, that is, the acquisition module 200 is the combination of the above-mentioned measuring device and the recording device, and the recording device can be an electronic device such as a computer, For example, when the above-mentioned measuring device rotates, the data is sent to the computer in real time through the wireless communication module, and the computer records and counts the received data correspondingly. Wherein, the wireless communication module may be a device with wireless communication functions, such as Bluetooth and a wireless network card. The critically refracted longitudinal wave acoustic time difference distribution determining unit 203 determines the distribution of the critically refracted longitudinal wave acoustic time difference corresponding to the measured point according to the time duration of the critically refracted longitudinal wave received at each circumferential angle of the measured point.

The acquisition module 200 excites ultrasonic waves in the circumferential direction of each measured point through the ultrasonic generator, and acquires the distribution of the acoustic time difference of the critically refracted longitudinal wave formed on the surface of the measured component in the circumferential direction of the measured point.

In another specific embodiment, the recording device may be a conventional digital recording device, such as a digital recorder, etc. The present invention does not limit whether it is a computer to implement the above-mentioned recording function.

The determination module 300 may be an electronic device such as a computer, which has a certain calculation or processing capability, and can further determine the residual stress of the measured component according to the distribution of the acoustic transit time of each critical refracted longitudinal wave.

In a specific embodiment, the acoustic time difference is measured by the following method:

If the ultrasonic propagation time t ₀ corresponding to the zero stress σ ₀ of the material is measured and the ultrasonic propagation time t corresponding to the measured stress σ, then σ-σ ₀ =L(tt ₀ ) or △σ=L△t;

Δt is the variation difference of ultrasonic propagation time (acoustic time difference), Δt=tt ₀ ;

△σ is the residual stress variation, △σ=σ-σ ₀ ;

L is a constant, calibrated according to the actual detection.

As shown in FIG. 21 , in this embodiment, the determining module 300 includes an acoustic time difference distribution curve determining unit 301 and an acoustic time difference distribution curve determining unit 302 . Wherein, the acoustic time difference distribution curve determination unit 301 determines the critical refraction longitudinal wave acoustic time difference distribution curve corresponding to each measured point according to the distribution of each critical refracted longitudinal wave acoustic time difference; The time difference distribution curve determines the residual stress of the part under test.

After obtaining the critical refraction longitudinal wave acoustic time difference distribution curve of each measured point, it is necessary to find the maximum value on the curve and the angle corresponding to the maximum value. The stronger the acoustic time difference, the greater the stress on the material. Then the maximum value corresponds to the maximum stress value of the point in the angle. Further, the residual stress of the entire tested component can be determined according to the maximum stress value and the corresponding angle. Therefore, as shown in FIG. 22 , the acoustic time difference distribution curve conforming unit 302 includes:

The maximum value searching unit 302a obtains the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value according to the distribution curve of each critical refracted longitudinal wave acoustic time difference.

The maximum value based unit 302b determines the residual stress of the component under test according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value.

Further, during specific implementation, as shown in FIG. 23 , the maximum value basis unit 302b includes:

The residual stress distribution determining unit 302b-1 determines the residual stress distribution of the measured component according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point;

The residual stress direction change trend determination unit 302b-2 determines the residual stress direction change trend of the measured component according to each angle corresponding to the maximum value;

The residual stress determination unit 302b-3 determines the residual stress of the tested component according to the residual stress distribution and the change trend of the residual stress direction.

Two pieces of information can be obtained according to the maximum value and the corresponding angle. The maximum value can be used to determine the residual stress distribution of the component under test, which is equivalent to ignoring the residual stress in the remaining directions. The most significant stress of each measured point is taken as the "represent". Then, the residual stress distribution of the measured component is determined according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point. In addition, the change trend of the residual stress direction of the component under test can be determined according to the corresponding angle, so that the residual stress of the complete component under test can be determined by combining the two.

Based on the above embodiments of the residual stress determination method, in some optional embodiments, the residual stress distribution can be mapped to a visible or identifiable image, a post-curve model, or the like. For example, referring to Fig. 11, it can be known that the residual stress distribution can be mapped into a three-dimensional model represented by a peak value through a certain mapping relationship. In the three-dimensional model, the height represents the magnitude of the residual stress, and the height of each measured point is different, and then The formation of "mountain peaks" of different heights.

Or, in order to show the residual stress distribution of the tested part more concretely and vividly, it can be mapped to a shape-independent variable, which can be directly reflected on the tested part, which is more vivid and clear. In this embodiment, as shown in FIG. 24 , that is, the residual stress distribution determining unit 302b-1 includes:

The gray value corresponding unit 302b-1-a determines the gray value corresponding to the maximum value of the critical refraction longitudinal wave acoustic time difference of each measured point based on the preset correspondence between the critical refraction longitudinal wave acoustic time difference and the gray value;

The distribution determining unit 302b-1-b determines, according to each grayscale value, the residual stress distribution of the component under test displayed in grayscale.

It can be known from FIG. 13 that the preset corresponding relationship between the critical refraction longitudinal wave acoustic time difference and the gray value may be a gray value mapping of the color corresponding to the critical refraction longitudinal wave acoustic time difference. In one embodiment, the preset corresponding relationship between the critical refraction longitudinal wave acoustic time difference and the gray value is a gray scale model as shown in FIG. 13 . For the sake of clarity, the gray value in the figure is from black to hundred. The range is generally from 0 to 255, with 255 for white and 0 for black. The black corresponds to 200Mpa, and the white corresponds to 400Mpa, as shown in Figure 13.

It can be seen from Figure 13 that the intensity values A-B (linearly increasing), corresponding to black-to-white changes. In this way, through the grayscale correspondence, the grayscale value Ci corresponding to each intensity value can be obtained, so that the residual stress distribution can be determined by the grayscale change on the measured component.

Further, in some embodiments, in order to better reflect the change trend of the residual stress direction, the trend may be expressed in the form of a network curve, as shown in FIG. 25 , the residual stress direction change trend determination unit 302b-2 include:

The curvature correspondence unit 302b-2-a determines a direction curve corresponding to each measured point one-to-one according to the angle corresponding to the maximum value of each measured point based on the preset corresponding relationship between the angle and the curvature;

The direction change trend determination unit 302b-2-b fits each direction curve into a network curve set, and determines the direction change trend of residual stress of the component under test according to the fitted network curve set.

The network curve set is shown in Figure 15. In this figure, the angle corresponding to the maximum value of each measured point is converted into a curve with different curvatures according to the preset corresponding relationship between the angle and the curvature. Since the distribution of stress has a trend , the angle difference between the adjacent measured points and the maximum value is small. Therefore, each curve can be fitted and connected to form a network curve set, and the measured value can be determined according to the density and curvature distribution of the fitted network curve set. Variation trend of residual stress direction of components.

In some embodiments, the structure mapped to the gray value can be combined with the network curve set in a characterization model, so that the residual stress distribution expressed by the gray value and the trend expressed by the network curve set can be simultaneously integrated. Comprehensive situation of residual stress.

Of course, in other embodiments, the color value can be used instead of the above gray value, and the color value distribution can be obtained to express the residual stress distribution. The residual stress distribution expressed by the gray value is only expressed in grayscale, and the calculation is simple. The color value of the three primary colors The expression of residual stress distribution needs to be represented by three colors, which is more complex, but more comprehensive, and can be set in combination with specific actual conditions, and the present invention is not limited to this.

Based on the description of the above method, it can be known that the residual stress determination system provided by the present application can obtain the information on the surface of the measured component by setting multiple measured points on the surface of the component to be measured, and excites ultrasonic waves to each measured point one by one. The distribution of the acoustic time difference of the formed critical refracted longitudinal wave in the circumferential direction of the measured point determines the residual stress of the measured component. Compared with the current measurement of one or very few points, the residual stress of a measured point can be measured more accurately. The practice shows that the residual stress after elimination can also be accurately measured and characterized. Obviously, the residual stress relief effect of the material can be accurately determined.

Further, similar to the method for determining the residual stress elimination effect of the isotropic material, the present invention further provides a system 400 for determining the residual stress elimination effect of the isotropic material, as shown in FIG. 26 , comprising: :

The residual stress determination module 401 after elimination is used to determine the residual stress after elimination of the component under test by using the residual stress determination method as described above;

The elimination effect determination module 402 determines the elimination effect of the tested component according to the residual stress of the tested component after elimination.

According to the characteristics of the aforementioned isotropic materials, it can be known that, in the case of no stress, the critical refraction longitudinal wave acoustic transit time-angle distribution curve of the tested component is shown in Figure 3. Since the external environment such as temperature and pressure makes the stress generated by the component under test too small compared with the stress generated by welding and other processes, it can be ignored. Therefore, it can be assumed that the critical refraction longitudinal wave acoustic transit time-angle distribution curve is shown in Fig. 3. In this way, by comparing the critical refraction longitudinal wave acoustic time difference-angle distribution curve of the measured component after elimination with the distribution curve in Fig. 3, we can know the residual stress of each measured point after elimination, and then know the entire measured point. The annihilation effect of the part.

Based on the same reason, the present invention further provides a system for determining the residual stress elimination effect of anisotropic materials, which is the same as the above-mentioned method for determining residual stress of the present application, but the difference is that the anisotropic materials do not When performing welding and other process operations, due to the effect of anisotropy, the stress generated by the influence of the same external environment is different. If it is ignored, the error will be large, so it needs to be compared and verified. 26, the system 400 includes:

The residual stress determination module 401 after elimination is used to determine the residual stress of the tested component before and after elimination by using the method for determining residual stress as described above;

The elimination effect determination module 402 determines the elimination effect of the tested component by comparing the residual stress of the tested component before and after elimination.

That is, in this embodiment, the above method needs to be used to determine the residual stress before and after elimination, and then the elimination effect is determined by comparing the residual stress of the tested component before and after elimination.

From the above examples of isotropic and anisotropic materials, it can be known that the present application can accurately detect the residual effect of isotropic and anisotropic components under test, which solves the current lack of detection of residual effect. technical issues and obstacles.

The embodiment of the present application also provides a specific implementation manner of an electronic device, referring to FIG. 27 , the electronic device specifically includes the following contents:

a processor (processor) 601, a memory (memory) 602, a communication interface (CommunicationsInterface) 603 and a bus 604;

Wherein, the processor 601, the memory 602, and the communication interface 603 complete the mutual communication through the bus 604; the communication interface 603 is used for the information transmission of the above-mentioned measuring device, recording device, determination module, etc.;

The processor 601 is configured to call a computer program in the memory 602, and the processor implements at least one of the following steps when executing the computer program:

Determine the residual stress of the tested component according to the distribution of the acoustic time difference of each critical refracted longitudinal wave;

The annihilation effect of the tested part is determined based on the residual stress of the tested part after annihilation.

The embodiments of the present application further provide a computer-readable storage medium capable of realizing at least part of the steps in the residual stress determination method and the elimination effect determination method in the foregoing embodiments, where a computer program is stored on the computer-readable storage medium, The computer program, when executed by the processor, implements at least one of the following steps:

Determine the residual stress of the tested component according to the distribution of the acoustic time difference of each critical refracted longitudinal wave;

The annihilation effect of the tested part is determined based on the residual stress of the tested part after annihilation.

Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the hardware+program embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for related parts, please refer to the partial description of the method embodiment. Although the embodiments of the present specification provide method operation steps as described in the embodiments or flow charts, more or less operation steps may be included based on conventional or non-creative means. The sequence of steps enumerated in the embodiments is only one of the execution sequences of many steps, and does not represent the only execution sequence. When an actual device or terminal product is executed, it can be executed sequentially or in parallel according to the methods shown in the embodiments or the drawings (eg, a parallel processor or multi-threaded processing environment, or even a distributed data processing environment). The terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, product or device comprising a list of elements includes not only those elements, but also others not expressly listed elements, or also include elements inherent to such a process, method, product or device. Without further limitation, it does not preclude the presence of additional identical or equivalent elements in a process, method, product or apparatus comprising the stated elements. For the convenience of description, when describing the above device, the functions are divided into various modules and described respectively. Of course, when implementing the embodiments of this specification, the functions of each module may be implemented in the same one or more software and/or hardware, and the modules implementing the same function may be implemented by a combination of multiple sub-modules or sub-units. The apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated. to another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms. The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block in the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce Means for implementing the functions specified in a flow or flow of a flowchart and/or a block or blocks of a block diagram. As will be appreciated by one skilled in the art, the embodiments of the present specification may be provided as a method, a system or a computer program product. Accordingly, embodiments of this specification may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present specification may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein. Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and for related parts, please refer to the partial descriptions of the method embodiments. In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structures, materials, or features are included in at least one example or example of embodiments of this specification. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other. The above descriptions are merely examples of the embodiments of the present specification, and are not intended to limit the embodiments of the present specification. For those skilled in the art, various modifications and variations can be made to the embodiments of the present specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present specification shall be included within the scope of the claims of the embodiments of the present specification.

Claims (8)

1. A method for determining residual stress in a material, comprising:

arranging a plurality of measured points on the surface of a measured component according to a preset interval;

exciting ultrasonic waves in the circumferential direction of each measured point through an ultrasonic generator, and acquiring the distribution of the acoustic time difference of critical refraction longitudinal waves formed on the surface of the measured component in the circumferential direction of the measured point;

determining the residual stress of the tested component according to the distribution of the sound time difference of each critical refraction longitudinal wave;

the method for acquiring the distribution of the acoustic time difference of the critical refraction longitudinal wave formed on the surface of the measured component in the circumferential direction of the measured point by exciting the ultrasonic wave in the circumferential direction of each measured point by the ultrasonic generator comprises the following steps:

exciting ultrasonic waves in the circumferential direction of each measured point by an ultrasonic generator;

rotating the ultrasonic generator by taking a measured point as a center, and receiving formed critical refraction longitudinal waves through an ultrasonic receiver which is arranged opposite to the ultrasonic generator and rotates synchronously with the ultrasonic generator;

determining the distribution of the sound time difference of the critical refracted longitudinal waves corresponding to the measured point according to the time length of the critical refracted longitudinal waves received at each angle in the circumferential direction of the measured point;

determining the residual stress of the tested component according to the distribution of the sound time difference of each critical refraction longitudinal wave, wherein the method comprises the following steps:

determining critical refraction longitudinal wave sound time difference distribution curves corresponding to the measured points one by one according to the distribution of the critical refraction longitudinal wave sound time differences;

obtaining the maximum value of the critical refraction longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value according to each critical refraction longitudinal wave acoustic time difference distribution curve;

determining the residual stress distribution of the tested component according to the maximum value of the critical refraction longitudinal wave acoustic time difference of each tested point;

determining the direction change trend of the residual stress of the tested part according to each angle corresponding to the maximum value;

and determining the residual stress of the tested part according to the residual stress distribution and the residual stress direction change trend.

2. The determination method according to claim 1, wherein determining the residual stress distribution of the measured component according to the maximum value of the critical refracted longitudinal wave acoustic time difference of each measured point comprises:

determining a gray value corresponding to the maximum value of the critical refraction longitudinal wave sound time difference of each measured point based on the corresponding relation between the preset critical refraction longitudinal wave sound time difference and the gray value;

and determining the residual stress distribution of the tested part displayed in gray scale according to each gray scale value.

3. The method for determining according to claim 1, wherein determining the direction change trend of the residual stress of the measured component according to each angle corresponding to the maximum value comprises:

determining a direction curve corresponding to each measured point one by one according to the angle of each measured point corresponding to the maximum value based on the corresponding relation between the preset angle and the curvature;

and fitting each direction curve into a network curve set, and determining the direction change trend of the residual stress of the tested part according to the fitted network curve set.

4. The determination method according to claim 1, wherein the arranging of the plurality of measured points on the surface of the measured component at the predetermined intervals comprises:

dividing the surface of a tested part to form a grid array;

and setting the center of each grid in the grid array as the measured point.

5. A system for determining residual stress in a material, comprising:

the device comprises a measured point setting module, a data acquisition module and a data processing module, wherein a plurality of measured points are arranged on the surface of a measured component according to a preset interval;

the acquisition module is used for exciting ultrasonic waves in the circumferential direction of each measured point through the ultrasonic generator and acquiring the distribution of the acoustic time difference of the critical refraction longitudinal waves formed on the surface of the measured component in the circumferential direction of the measured point;

the determining module is used for determining the residual stress of the tested component according to the distribution of the sound time difference of each critical refraction longitudinal wave;

wherein the acquisition module comprises:

the ultrasonic excitation unit excites ultrasonic waves in the circumferential direction of each measured point through the ultrasonic generator;

the rotation recording unit rotates the ultrasonic generator by taking a measured point as a center, and receives formed critical refraction longitudinal waves through an ultrasonic receiver which is arranged opposite to the ultrasonic generator and rotates synchronously with the ultrasonic generator;

the critical refraction longitudinal wave sound time difference distribution determining unit is used for determining the distribution of the critical refraction longitudinal wave sound time difference corresponding to the measured point according to the time length of the critical refraction longitudinal wave received at each angle in the circumferential direction of the measured point;

the determining module comprises:

the acoustic time difference distribution curve determining unit is used for determining critical refraction longitudinal wave acoustic time difference distribution curves corresponding to the measured points one by one according to the distribution of the critical refraction longitudinal wave acoustic time differences;

the maximum value searching unit is used for obtaining the maximum value of the critical refraction longitudinal wave acoustic time difference of each measured point and the angle corresponding to the maximum value according to each critical refraction longitudinal wave acoustic time difference distribution curve;

the residual stress distribution determining unit is used for determining the residual stress distribution of the tested part according to the maximum value of the critical refraction longitudinal wave acoustic time difference of each tested point;

the residual stress direction change trend determining unit is used for determining the residual stress direction change trend of the tested part according to each angle corresponding to the maximum value;

and the residual stress determining unit is used for determining the residual stress of the tested part according to the residual stress distribution and the residual stress direction change trend.

6. The determination system according to claim 5, wherein the residual stress distribution determination unit includes:

the gray value corresponding unit is used for determining a gray value corresponding to the maximum value of the critical refraction longitudinal wave sound time difference of each measured point based on the preset corresponding relation between the critical refraction longitudinal wave sound time difference and the gray value;

and the distribution determining unit is used for determining the residual stress distribution of the tested part displayed in gray scale according to each gray scale value.

7. The determination system according to claim 5, wherein the residual stress direction change tendency determination unit includes:

the curvature corresponding unit is used for determining a direction curve corresponding to each measured point one by one according to the angle of each measured point corresponding to the maximum value based on the corresponding relation between the preset angle and the curvature;

and the direction change trend determining unit is used for fitting each direction curve into a network curve set and determining the direction change trend of the residual stress of the tested part according to the fitted network curve set.

8. The determination system according to claim 5, wherein the measured point setting module includes:

the grid array setting unit divides the surface of the tested part into grid arrays;

and the measured point setting unit is used for setting the center of each grid in the grid array as the measured point.

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