Method for residual stress elimination and detection based on laser ultrasound

Abstract

Embodiments of the present application provide a laser-ultrasonic residual stress relieving and detecting method, device, equipment and computer readable storage medium. The method comprises removing residual stress in a component by laser-ultrasonic method; detecting the residual stress in the component, and if the residual stress in the component exceeds a threshold value, removing the residual stress in the component again by laser-ultrasonic method until the residual stress in the component is less than or equal to the threshold value. In this way, effective and rapid elimination of the residual stress in the component and accurate detection of the residual stress in the component are achieved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of laser ultrasound, and in particular, to a method and device for residual stress elimination and detection based on laser ultrasound. BACKGROUND

[0002] After welding, casting, forging, machining and other processes, the internal crystal lattice of a metal component is deformed, which will inevitably cause residual stress, greatly reducing the ultimate strength and fatigue strength of the component, and even causing cracks and brittle fractures. In addition, due to the relaxation of residual stress during processing and use, the part will deform, greatly affecting the size, position accuracy and overall performance of the component.

[0003] Currently, the methods for reducing residual stress mainly include annealing, mechanical treatment, shot blasting, ultrasonic, explosion method, etc. Although the above methods can eliminate residual stress, there are still many defects. For example, shot blasting can only treat the surface residual stress, and the cost is high; ultrasonic is limited by energy density and can only be effective for some materials, and there is no corresponding residual stress detection method.

[0004] Therefore, how to effectively and quickly eliminate the residual stress inside the component and detect the residual stress of the component is a problem that needs to be solved at present. SUMMARY

[0005] According to embodiments of the present application, a residual stress elimination and detection scheme based on laser ultrasound is provided.

[0006] In a first aspect of the present application, a residual stress elimination and detection method based on laser ultrasound is provided. The method comprises:

[0007] eliminating residual stress inside a component by means of laser ultrasound;

[0008] detecting the residual stress inside the component, and if the residual stress inside the component exceeds a threshold value, eliminating the residual stress inside the component again by means of laser ultrasound until the residual stress inside the component is less than or equal to the threshold value.

[0009] Further, the eliminating residual stress inside the component by means of laser ultrasound comprises:

[0010] obtaining three-dimensional model data of the component;

[0011] generating a three-dimensional topographic model of the component based on the three-dimensional model data of the component;

[0012] determining a scanning path and a firing distance based on the three-dimensional topographic model of the component;

[0013] According to the scanning path and the excitation distance, the distance and the angle between the laser and the component are adjusted in real time, so that the laser reaches the excitation distance with the component surface, the laser power density of the laser is adjusted to emit laser to the component, and laser ultrasonic wave is excited on the component surface to remove residual stress in the component.

[0014] Further, the scanning path is determined based on the three-dimensional topographic model of the component, comprising:

[0015] Based on the three-dimensional topographic model of the component, the key points of the three-dimensional topography of the component are determined.

[0016] The scanning area is determined by the key points of the three-dimensional topography.

[0017] The scanning path is generated based on the scanning area.

[0018] Further, the key points of the three-dimensional topography of the component are determined based on the three-dimensional topographic model of the component, comprising:

[0019] According to the view angle of the three-dimensional topographic model, the key points of the three-dimensional topography of the component are determined.

[0020] Further, the scanning path is generated based on the scanning area, comprising:

[0021] If the scanning area is less than a threshold value, the scanning area is discretized into a scanning grid;

[0022] The scanning grid is discretized to obtain a series of scanning points.

[0023] The scanning path is generated based on the scanning points.

[0024] Further, the residual stress in the component is detected, comprising:

[0025] According to the scanning path and the excitation distance, the distance and the angle between the laser and the component are adjusted in real time, so that the laser reaches the excitation distance with the component surface, the laser is controlled to emit laser to the component, and multi-frequency narrow-band ultrasonic surface wave is generated on the component surface;

[0026] The surface wave depth and the surface wave velocity obtained by scanning the multi-frequency narrow-band ultrasonic surface wave along the scanning path are obtained.

[0027] The residual stress distribution in the component is calculated by the scanning path, the penetration depth of the multi-frequency narrow-band ultrasonic surface wave, the multi-frequency narrow-band ultrasonic surface wave velocity and the acoustic elastic principle, and it is determined whether the residual stress in the component is eliminated.

[0028] Further, the multi-frequency narrow-band ultrasonic surface wave is a dual-frequency narrow-band ultrasonic surface wave, which can be generated in the following way:

[0029] The laser is modulated by a double-period optical mask to form two kinds of periodical distribution gratings;

[0030] The width of the two kinds of periodical distribution gratings is adjusted to obtain high-low dual-frequency narrow-band ultrasonic surface waves.

[0031] In a second aspect of the present application, a laser ultrasonic-based residual stress elimination and detection device is provided. The device comprises:

[0032] an industrial computer, a mechanical arm, a laser, and a laser modulation module;

[0033] The industrial computer is configured to generate a three-dimensional topographic model of the component based on three-dimensional model data of the component.

[0034] Based on the three-dimensional topographic model of the component, a scanning path and an excitation distance are determined.

[0035] According to the scanning path and the excitation distance, the distance and angle between the laser and the component are adjusted in real time by the mechanical arm, so that the laser and the component surface reach the excitation distance, and the laser power density of the laser is adjusted.

[0036] The industrial computer further comprises a calculation module configured to calculate the residual stress distribution in the component by the scanning path, the penetration depth of the multi-frequency narrow-band ultrasonic surface wave, the speed of the multi-frequency narrow-band ultrasonic surface wave, and the acoustic-elastic principle, and determine whether the residual stress in the component is eliminated.

[0037] The laser is configured to emit laser to the component to excite laser ultrasonic waves on the surface of the component and eliminate the residual stress in the component.

[0038] The laser modulation module is configured to modulate the laser to generate narrow-band ultrasonic surface waves of multiple frequencies.

[0039] The mechanical arm is configured to adjust the distance and angle between the laser and the component in real time.

[0040] In a third aspect of the present application, an electronic device is provided. The electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to realize the method as described above.

[0041] In a fourth aspect of the present application, a computer readable storage medium is provided, which stores a computer program, and the program is executed by a processor to realize the method according to the first aspect of the present application.

[0042] The method for eliminating and detecting residual stress based on laser ultrasound provided by the embodiment of the application removes residual stress in a component by means of laser ultrasound; the residual stress in the component is detected, if the residual stress in the component exceeds a threshold value, the residual stress in the component is removed again by means of laser ultrasound until the residual stress in the component is less than or equal to the threshold value, thereby realizing effective and rapid elimination of residual stress in the component and accurate detection of residual stress in the component.

[0043] It should be understood that the content described in the summary section is not intended to limit the key or important features of the embodiments of the application, nor to limit the scope of the application. Other features of the application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0044] The above and other features, advantages and aspects of the embodiments of the application will become more apparent by describing in detail the following embodiments with reference to the attached drawings. In the drawings, the same or similar reference numerals refer to the same or similar elements, in which:

[0045] Figure 1 A flow chart of a method for eliminating residual stress based on laser ultrasound according to an embodiment of the application is shown;

[0046] Figure 2 A schematic diagram of a scanning path planning method according to an embodiment of the application is shown;

[0047] Figure 3 A schematic diagram of another scanning path planning method according to an embodiment of the application is shown;

[0048] Figure 4 A flow chart of detecting residual stress in a component according to an embodiment of the application is shown;

[0049] Figure 5 A structural schematic diagram of generating dual-frequency narrow-band ultrasonic surface waves according to an embodiment of the application is shown;

[0050] Figure 6 A block diagram of a device for eliminating and detecting residual stress based on laser ultrasound according to an embodiment of the application is shown;

[0051] Figure 7 A structural schematic diagram of a terminal device or server suitable for implementing the embodiments of the application is shown. DETAILED DESCRIPTION

[0052] In order to make the purposes, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present disclosure.

[0053] In addition, the term "and / or" in this document is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this document generally represents an "or" relationship between the front and rear associated objects.

[0054] Figure 1 A flowchart of a laser-ultrasound-based residual stress elimination and detection method according to an embodiment of the present disclosure is shown. The method comprises:

[0055] S110, removing residual stress in the component by means of laser ultrasound.

[0056] In some embodiments, the three-dimensional model data of the component can be directly obtained by means of three-dimensional scanning, computer interface import, and / or contour parameter setting; or the two-dimensional image of the component can be obtained by means of a binocular camera or the like, and the two-dimensional image is converted into the three-dimensional model data of the component. That is, the component is photographed by means of a binocular camera to obtain a synchronous exposure image. The third-dimensional depth information of the image is determined by means of the two-dimensional image pixels of the image, and then the three-dimensional topography of the component is fused and spliced according to the image to generate the three-dimensional model data of the component.

[0057] The image acquisition by means of the binocular camera further reduces the hardware cost, and a common CMOS camera can be used, and it is applicable indoors and outdoors.

[0058] In some embodiments, the three-dimensional model data comprises the topography, position, size, bending, compression, shearing, tension, torsion, and / or composite stress of the component, and the like.

[0059] In some embodiments, the component is generally a variety of transparent solid materials such as steel, aluminum alloy, copper alloy, titanium alloy, and / or high-temperature alloy.

[0060] In some embodiments, the three-dimensional topography model of the component is generated by means of a three-dimensional modeling software based on the three-dimensional model data of the component.

[0061] S130, determining a scanning path and an excitation distance based on the three-dimensional topography model of the component.

[0062] In some embodiments, based on the three-dimensional topography of the component, key points of the three-dimensional topography are determined; the key points include edge points and / or geometric centers, etc.

[0063] Further, based on the key points of the three-dimensional topography, a scanning region is determined, if the scanning region is smaller than a preset range, a path of scanning can be planned in a manner of approaching from the middle to the edge as shown in FIG. 6, or a path of scanning can be planned in a manner of sequential scanning as shown in FIG. 7. Figure 2 Further, based on the key points of the three-dimensional topography, a scanning region is determined, if the scanning region is smaller than a preset range, a path of scanning can be planned in a manner of approaching from the middle to the edge as shown in FIG. 6, or a path of scanning can be planned in a manner of sequential scanning as shown in FIG. 7. Figure 3 Further, based on the key points of the three-dimensional topography, a scanning region is determined, if the scanning region is smaller than a preset range, a path of scanning can be planned in a manner of approaching from the middle to the edge as shown in FIG. 6, or a path of scanning can be planned in a manner of sequential scanning as shown in FIG. 7.

[0064] If the scanning region is larger than the preset range, the scanning region is first discretized into a plurality of small scanning grids, and then the small scanning grids are further discretized into a series of scanning points, and a path of scanning is planned through the scanning points.

[0065] The preset range can be set according to actual application scenarios.

[0066] In some embodiments, the discretized scanning grids can be automatically divided according to the size of the scanning region. If the scanning region is a rectangular region, it can be directly divided into square or rectangular regions; if the scanning region is a non-rectangular region, the central region can be divided into square or rectangular regions, and the edge region is generally divided into triangular regions, i.e., the edge region is completed by using triangular regions.

[0067] Optionally, the movement between the scanning grids can adopt a mechanical arm movement manner.

[0068] In some embodiments, when planning a path of a multi-faceted component, in order to improve the subsequent scanning efficiency, key points of the three-dimensional topography of the component can be determined according to a view angle of the three-dimensional topography model. That is, the path planning is respectively performed according to different view angles, and after the component scanning of the same view angle is completed, the component scanning of the next view is performed (after the scanning of one face is completed, the scanning of the next face is performed).

[0069] The view angle includes a front view, a rear view, a left view, a right view, a top view and / or a bottom view, etc., and reference is made to the patent appearance 6 views; the path planning of each face can refer to the path planning method described above, which will not be described herein.

[0070] In some embodiments, the three-dimensional point cloud in the scanning region is planarly fitted to determine the normal direction of the region, and according to the transformation relationship between the component and the three-dimensional space posture of the mechanical arm (the transformation relationship can be obtained through the space calibration of the mechanical arm), the mechanical arm is adjusted to be perpendicular to the local plane of the component scanning region, and the mechanical arm is connected with the laser, i.e., the laser is adjusted to be perpendicular to the local plane of the component scanning region.

[0071] Meanwhile, according to the above transformation relationship, the mechanical arm posture is adjusted, in the case of satisfying the perpendicularity between the laser and the component surface, the pre-set excitation distance is reached, and the laser power reaches the stable purpose with each switching of the scanning position.

[0072] It should be noted that the most ideal state is when the laser is perpendicular to the component surface, and the stress inside the component can be eliminated in the shortest time. However, in actual application, for components such as the interior of a reciprocating engine, which are not easy to perform vertical scanning, the angle of the laser irradiation to the component can also be adjusted according to the actual application scene, so that the laser spot formed by the laser can irradiate the component surface. Although the efficiency will decrease to a certain extent, stress elimination can still be performed.

[0073] Further, the laser power density, laser energy and / or pulse frequency and other parameters of the laser are adjusted to form laser ultrasound, so as to avoid the formation of shock waves, causing sample impact damage or causing plastic deformation. The laser emits laser light to the component on the scanning path, and excites laser ultrasound on the component surface. The ultrasound propagates inside the component, and through repeated loading and reflection, acts on the lattice dislocation, so that the distorted lattice returns to the equilibrium state, so as to achieve the purpose of removing the residual stress in the component. That is, the pulsed laser is focused on the component surface to generate laser ultrasound, and the laser ultrasound is reflected multiple times inside the material, repeatedly loaded and unloaded, and plastic deformation is generated, so that the residual stress is released.

[0074] Due to the characteristics of laser ultrasound, such as high time resolution and spatial resolution, rich waveforms, wide-band ultrasound, etc., the stress inside the actual workpiece can be non-contact, remote control and non-destructive stress detection and stress control in the stress concentration area. The detection and control method is suitable for removing the residual stress on the surface, inside and back of various sound-transparent solid materials such as steel, aluminum alloy, copper alloy, titanium alloy and high-temperature alloy.

[0075] S120, detecting the residual stress in the component, and if the residual stress in the component exceeds the threshold value, removing the residual stress in the component again by means of laser ultrasound until the residual stress in the component is less than or equal to the threshold value.

[0076] In some embodiments, in order to ensure that the stress inside the component reaches the pre-set standard (threshold value), the residual stress inside the component needs to be detected; the pre-set standard can be set according to the material quality of the component and / or the application environment.

[0077] In some embodiments, the residual stress of the component can be detected by a traditional ultrasonic surface wave method.

[0078] In some embodiments, in the application scenarios of component surface roughness, plating, coating, etc., the measurement of residual stress position of parts is prone to error by traditional ultrasonic surface wave method. Therefore, in the above scenarios, the measurement of residual stress inside the component can be performed in the following manner, for reference Figure 4 :

[0079] S410, according to the scanning path and the excitation distance, adjusting the distance and angle between the laser and the component in real time, so that the laser and the component surface reach the excitation distance, controlling the laser to emit laser to the component, and generating multi-frequency narrow-band ultrasonic surface waves on the component surface.

[0080] In some embodiments, the step of adjusting the distance and angle between the laser and the component can refer to the corresponding step in step S110, which will not be described here.

[0081] In some embodiments, the laser is adjusted to simultaneously generate ultrasonic surface waves of different depths on the component surface, for reference Figure 5 , wherein λ0 is a high-frequency narrow-band laser ultrasonic surface wave, and λ1 is a low-frequency narrow-band laser ultrasonic surface wave.

[0082] S420, obtaining the multi-frequency narrow-band ultrasonic surface waves, and the surface wave depth and surface wave speed obtained by scanning along the scanning path.

[0083] In some embodiments, the ultrasonic surface waves λ0 and λ1 of the moving direction of the laser on the scanning path are obtained, that is, the surface wave depth and surface wave speed are obtained.

[0084] S430, calculating the residual stress distribution inside the component by the scanning path, the penetration depth of the multi-frequency narrow-band ultrasonic surface waves, the multi-frequency narrow-band ultrasonic surface wave speed, and the acoustic-elastic principle, and determining whether the residual stress inside the component is eliminated.

[0085] In the present disclosure, the relationship between the wave speed, wavelength and frequency of the surface wave is defined by the following formula:

[0086] c = λf

[0087] Wherein, c is the ultrasonic surface wave speed (m / s);

[0088] λ is the ultrasonic surface wave wavelength (nm);

[0089] f is the ultrasonic surface wave frequency (MHz).

[0090] The incident depth formula of the surface wave is:

[0091] h = 2aλ

[0092] Wherein, h is the incident depth of the ultrasonic surface wave (mm);

[0093] α is a correction factor.

[0094] Further, combined with the acoustic elasticity principle, the calculation formula of the residual stress is:

[0095] σ-σ0=K(t-t0) or Δσ=KΔt

[0096] wherein Δσ is the change amount of the residual stress (stress difference), σ=σ-σ0;

[0097] Δt is the change amount of the propagation time (acoustic time difference), t=t-to;

[0098] K is a stress coefficient, which is related to the material of the workpiece to be detected and the probe distance, and can be obtained by tensile test calibration.

[0099] In some embodiments, for example, laser ultrasonic surface waves with wavelengths λ0 and λ1 are excited on the surface of the workpiece to be detected at the same time, and h1 and h2 are the incident depths of the laser ultrasonic surface waves, respectively. According to the acoustic elasticity theory, the residual stresses σ1 and σ2 at depths h1 and h2 in the workpiece to be detected can be obtained, respectively. The residual stresses of the laser ultrasonic surface waves with two frequencies h1 and h2 are processed by difference, and the residual stresses at depths h1 and h2-h1 can be obtained, respectively, which are σ1 and σ2-σ1, respectively. Similarly, the residual stress distribution at different penetration depths of other dual-frequency narrow-band ultrasonic surface waves can be obtained.

[0100] Further, when the residual stress in the component is detected to exceed a threshold value, step 110 is repeated until the residual stress in the component is less than or equal to the threshold value.

[0101] According to the embodiments of the present disclosure, the following technical effects are achieved:

[0102] The blank of residual stress processing of stress concentration positions in local positions of complex structures is filled, and the present application is suitable for scientific research and various engineering application occasions. The effective and rapid elimination of the residual stress in the component and the accurate detection of the residual stress in the component are achieved.

[0103] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the action order described, because according to the present application, certain steps can be performed in other order or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to optional embodiments, and the actions and modules involved are not necessarily required by the present application.

[0104] The above is the introduction of the method embodiment, and the scheme described in the present application will be further described through the device embodiment below.

[0105] Figure 6 A block diagram of a laser-ultrasound-based residual stress elimination and detection device 600 according to an embodiment of the present application is shown as follows Figure 6 As shown, the device 600 includes an industrial computer, a mechanical arm, a laser, and a laser modulation module:

[0106] The industrial computer 610 is configured to generate a three-dimensional topography model of the component based on three-dimensional model data of the component.

[0107] Based on the three-dimensional topography model of the component, a scanning path and an excitation distance are determined.

[0108] According to the scanning path and the excitation distance, the distance and the angle between the laser and the component are adjusted in real time by the mechanical arm, so that the laser and the component surface reach the excitation distance, and the laser power density of the laser is adjusted.

[0109] The industrial computer further includes a calculation module configured to calculate the residual stress distribution in the component by the scanning path, the penetration depth of the multi-frequency narrowband ultrasonic surface wave, the speed of the multi-frequency narrowband ultrasonic surface wave, and the acoustic-elastic principle, and determine whether the residual stress in the component is eliminated.

[0110] The laser 620 is configured to emit laser to the component to excite laser ultrasound on the component surface and remove the residual stress in the component.

[0111] The laser modulation module 630 is configured to modulate the laser to generate narrowband ultrasonic surface waves of multiple frequencies.

[0112] The mechanical arm 640 is configured to adjust the distance and the angle between the laser and the component in real time.

[0113] Further, in actual applications, in order to achieve better stress elimination effect, the laser-ultrasound-based residual stress elimination device 600 further includes a water generator and a galvanometer:

[0114] The water generator is configured to spray water to the component surface to form a water film (water constraint layer) on the component surface to improve the intensity and duration of the laser ultrasound.

[0115] The galvanometer is configured to realize small-area rapid scanning of the component by controlling the deflection angle of the laser beam.

[0116] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the described modules can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0117] Figure 7A structure diagram of a terminal device or a server suitable for implementing the embodiments of the present application is shown.

[0118] As shown in Figure 7 the terminal device or the server includes a central processing unit (CPU) 701 which can perform various appropriate actions and processes in accordance with a program stored in a read only memory (ROM) 702 or a program loaded from a storage section 708 into a random access memory (RAM) 703. In the RAM 703, various programs and data required for the operation of the terminal device or the server are also stored. The CPU 701, the ROM 702, and the RAM 703 are connected to each other through a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0119] The following components are connected to the I / O interface 705: an input section 706 including a keyboard, a mouse, etc.; an output section 707 including a display such as a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 708 including a hard disk, etc.; and a communication section 709 including a network interface card such as a LAN card, a modem, etc. The communication section 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as necessary. A removable recording medium 711 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is attached to the drive 710 as necessary, so that a computer program read therefrom is installed into the storage section 708 as necessary.

[0120] In particular, according to the embodiments of the present application, the above method flow steps can be implemented as a computer software program. For example, the embodiments of the present application include a computer program product comprising a computer program carried on a machine-readable medium, the computer program containing program code for executing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network by the communication section 709, and / or installed from the removable recording medium 711. When the computer program is executed by the central processing unit (CPU) 701, the above-described functions defined in the system of the present application are performed.

[0121] It should be noted that the computer-readable medium shown in this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0122] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0123] The units or modules described in the embodiments of the present application can be implemented in the form of software or in the form of hardware. The units or modules described can also be arranged in a processor. In some cases, the names of the units or modules do not constitute a limitation on the units or modules themselves.

[0124] As another aspect, the present application also provides a computer readable storage medium, which can be included in the electronic device described in the above embodiments, or can exist separately without being assembled into the electronic device. The computer readable storage medium stores one or more programs, and the programs are used by one or more processors to execute the methods described in the present application.

[0125] The above description is merely preferred embodiments of the present application and a description of the principles of the technology used. Those skilled in the art should understand that the scope of the application described in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by the combinations of the above technical features or their equivalent features without departing from the above application concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features applied in the present application (but not limited to) having similar functions.

Claims

1. A method of laser-ultrasound based residual stress relief and detection, characterized in that, The method comprises the following steps: removing residual stress in the component by means of laser ultrasound; detecting the residual stress in the component, and removing the residual stress in the component by means of laser ultrasound again until the residual stress in the component is less than or equal to a threshold value if the residual stress in the component exceeds the threshold value; the step of removing the residual stress in the component by means of laser ultrasound comprises the following steps: obtaining three-dimensional model data of the component; generating a three-dimensional topographic model of the component based on the three-dimensional model data of the component; the three-dimensional model data comprises stress data of the component; the stress data comprises compression, shear, tension, torsion or combined stress; determining a scanning path and an excitation distance based on the three-dimensional topographic model of the component; adjusting the distance and angle between the laser and the component in real time according to the scanning path and the excitation distance, so that the laser and the surface of the component reach the excitation distance, adjusting the laser power density of the laser to emit laser to the component, exciting laser ultrasound on the surface of the component, and removing the residual stress in the component by the multiple loading and reflection of the laser ultrasound in the process of propagation in the component acting on the lattice dislocation; the step of determining the scanning path based on the three-dimensional topographic model of the component comprises the following steps: determining key points of the three-dimensional topography of the component based on the three-dimensional topographic model of the component; the key points comprise edge points and / or geometric centers; determining a scanning area through the key points of the three-dimensional topography; generating a scanning path based on the scanning area; the step of detecting the residual stress in the component comprises the following steps: adjusting the distance and angle between the laser and the component in real time according to the scanning path and the excitation distance, so that the laser and the surface of the component reach the excitation distance, controlling the laser to emit laser to the component to generate multi-frequency narrow-band ultrasonic surface waves on the surface of the component; the multi-frequency narrow-band ultrasonic surface waves comprise high-frequency narrow-band laser ultrasonic surface waves and low-frequency narrow-band laser ultrasonic surface waves; obtaining the surface wave depth and surface wave velocity obtained by scanning the multi-frequency narrow-band ultrasonic surface waves along the scanning path; processing the residual stress of the laser ultrasonic surface waves of the two frequencies by difference through the scanning path, the penetration depth of the multi-frequency narrow-band ultrasonic surface waves, the velocity of the multi-frequency narrow-band ultrasonic surface waves and the acoustic elastic principle, to obtain the residual stress distribution of the dual-frequency narrow-band ultrasonic surface waves at different penetration depths; calculating the residual stress distribution in the component to determine whether the residual stress in the component is eliminated.

2. The method of claim 1, wherein, the step of determining the key points of the three-dimensional topography of the component based on the three-dimensional topographic model of the component comprises the following steps: determining the key points of the three-dimensional topography of the component according to the view angle of the three-dimensional topographic model.

3. The method of claim 2, wherein, the step of generating a scanning path based on the scanning area comprises the following steps: if the scanning area is less than a threshold value, discretizing the scanning area into a scanning grid; discretizing the scanning grid to obtain a series of scanning points; generating a scanning path based on the scanning points.

4. The method of claim 1, wherein, the multi-frequency narrow-band ultrasonic surface waves are dual-frequency narrow-band ultrasonic surface waves, which can be generated by the following method: The laser is modulated by a double-period optical mask to form two periodic distribution gratings; The width of the two periodic distribution gratings is adjusted to obtain high-low dual-frequency narrow-band ultrasonic surface waves.

5. A laser-ultrasound based residual stress relieving and detecting apparatus, characterized by, The system comprises an industrial computer, a mechanical arm, a laser, and a laser modulation module. The industrial computer is configured to generate a three-dimensional topography model of the component based on three-dimensional model data of the component. The three-dimensional topography model of the component is used to determine a scanning path and an excitation distance. The distance and angle between the laser and the component are adjusted in real time by the mechanical arm according to the scanning path and the excitation distance, so that the laser and the component surface reach the excitation distance, and the laser power density of the laser is adjusted. The industrial computer further comprises a calculation module configured to calculate the residual stress distribution in the component by the scanning path, the penetration depth of the multi-frequency narrow-band ultrasonic surface wave, the multi-frequency narrow-band ultrasonic surface wave speed, and the acoustic elastodynamics principle, and determine whether the residual stress in the component is eliminated, so as to detect the residual stress in the component. The laser is configured to emit laser to the component to excite laser ultrasonic waves on the component surface, and the laser ultrasonic waves act on the lattice dislocation through multiple loading and reflection during the propagation in the component, so as to remove the residual stress in the component. The laser modulation module is configured to modulate the laser to generate narrow-band ultrasonic surface waves of multiple frequencies. The mechanical arm is configured to adjust the distance and angle between the laser and the component in real time. The three-dimensional topography model of the component is used to determine a scanning path, which comprises: The three-dimensional topography model of the component is used to determine key points of the three-dimensional topography of the component, wherein the key points include edge points and / or geometric centers. The key points of the three-dimensional topography are used to determine a scanning area. The scanning area is used to generate a scanning path. Detecting the residual stress in the component comprises: The distance and angle between the laser and the component are adjusted in real time according to the scanning path and the excitation distance, so that the laser and the component surface reach the excitation distance, the laser is controlled to emit laser to the component, and multi-frequency narrow-band ultrasonic surface waves are generated on the component surface; the multi-frequency narrow-band ultrasonic surface waves include high-frequency narrow-band laser ultrasonic surface waves and low-frequency narrow-band laser ultrasonic surface waves. The multi-frequency narrow-band ultrasonic surface waves are obtained, and the surface wave depth and the surface wave speed obtained by scanning along the scanning path are obtained. The residual stress of the two-frequency laser ultrasonic surface waves is processed by difference based on the scanning path, the penetration depth of the multi-frequency narrow-band ultrasonic surface wave, the multi-frequency narrow-band ultrasonic surface wave speed, and the acoustic elastodynamics principle, so as to obtain the residual stress distribution of the dual-frequency narrow-band ultrasonic surface wave at different penetration depths. The residual stress distribution in the component is calculated to determine whether the residual stress in the component is eliminated. 6.An electronic device comprising a memory and a processor, the memory having stored thereon a computer program, characterized in that, The processor executes the computer program to implement the method of any one of claims 1-4.

7. A computer-readable storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement the method of any one of claims 1-4.

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