Residual stress composite detection device and method based on pulsed eddy current and nanoindentation

Abstract

The present invention discloses a residual stress composite detection device and method based on pulsed eddy current and nanoindentation, which relates to the field of nondestructive testing technology. A fixture module is installed in the middle of the upper end of a support module and is used to clamp the workpiece to be tested. A motion scanning module is installed at the upper end of the support module and its output end is connected to a nanoindentation loading and detection module. The motion scanning module can drive the nanoindentation loading and detection module to move in multiple directions. The output end of the nanoindentation loading and detection module is connected to a pulsed eddy current nondestructive testing module. The pulsed eddy current nondestructive testing module is located above the workpiece to detect the residual stress inside the workpiece to be tested. A parallel detection control module is used to control the pulsed eddy current nondestructive testing module to adjust the distance between the pulsed eddy current nondestructive testing module and the surface of the workpiece to be tested. The parallel detection control module is also used to control the movement of the motion scanning module. The present invention can realize synchronous and in-situ testing of residual stress of the machined surface and sub-surface metal materials of the workpiece to be tested.

Description

Technical Field

[0001] The present invention relates to the technical field of non-destructive testing, and in particular to a residual stress composite detection device and method based on pulsed eddy current and nanoindentation. Background Art

[0002] The residual stress distribution formed in metal materials during manufacturing processes such as machining, surface modification, and heat treatment will directly affect the reliability and durability of the materials and their products during service. Research on online detection technology for residual stress in metal materials during manufacturing has received great attention.

[0003] Compared to traditional destructive residual stress testing techniques such as the blind hole method and the peeling method, methods based on X-ray / neutron diffraction, eddy current / ultrasonic testing, and nanoindentation can perform micro-destructive / non-destructive testing on the material being tested without destroying the integrity of the structural component. However, traditional single-dimensional testing methods can usually only obtain the stress state of the surface / subsurface in a single dimension, making it difficult to evaluate the distribution of normal residual stress. They also place high demands on instrumentation and testing costs, making it difficult to achieve high-throughput online testing during the manufacturing process. Although ultrasonic testing can evaluate the residual stress within the material, its low spatial resolution cannot obtain high-precision test data. Indentation testing technology, with its advantages of high precision, rich test information, and surface micro-damage, has been widely used to determine mechanical parameters such as elastic modulus and hardness of materials. In recent years, methods for detecting residual stress based on nanoindentation have developed rapidly. Combining methods such as dimensional analysis, indentation energy method, and numerical simulation, the functional relationship between residual stress and indentation response parameters and material mechanical parameters has been established through inversion. However, the above residual stress expressions are usually based on the assumption of equiaxed surface residual stress and require a stress-free reference specimen as a benchmark, which is contrary to actual engineering needs. Therefore, the existing residual stress indentation detection technology is limited in practical engineering applications.

[0004] Pulsed eddy current nondestructive testing technology, because it can overcome the influence of the skin effect and contains rich spectral signals, can quantitatively measure the residual stress inside the material through the frequency domain differential signal amplitude / frequency and zero-crossing frequency. Based on this, the organic combination of pulsed eddy current testing and indentation testing technology is expected to achieve online detection of residual stress on the machined surface, making it possible to accurately measure the three-dimensional residual stress distribution of metal materials from the surface to the inside at high throughput and low cost. However, to date, there are few reports on the actual engineering application of instruments developed using this approach, and there are still theoretical and technical issues that need to be studied and resolved. Summary of the Invention

[0005] The purpose of the present invention is to provide a residual stress composite detection device and method based on pulsed eddy current and nanoindentation to solve the problems existing in the above-mentioned prior art and realize synchronous and in-situ testing of residual stress of the machined surface and sub-surface metal materials of the workpiece being tested.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a residual stress composite detection device based on pulsed eddy current and nanoindentation, comprising a pulsed eddy current nondestructive testing module, a nanoindentation loading and detection module, a motion scanning module, a fixture module, a support module and a parallel detection control module, wherein the fixture module is installed at the middle part of the upper end of the support module and is used to clamp a workpiece to be measured, the motion scanning module is installed at the upper end of the support module, and the output end of the motion scanning module is connected to the nanoindentation loading and detection module, the motion scanning module can drive the nanoindentation loading and detection module to move in multiple directions, the output end of the nanoindentation loading and detection module is connected to the pulsed eddy current nondestructive testing module, the pulsed eddy current nondestructive testing module is located above the workpiece to be measured and is used to detect the residual stress inside the workpiece to be measured, the parallel detection control module is electrically connected to the pulsed eddy current nondestructive testing module and is used to control the pulsed eddy current nondestructive testing module to adjust the distance between the pulsed eddy current nondestructive testing module and the surface of the workpiece to be measured, and the parallel detection control module is also electrically connected to the motion scanning module and is used to control the movement of the motion scanning module.

[0008] In one embodiment, the support module includes a base and a T-shaped stage, the base is I-shaped, and the two sides of the base are higher than the middle of the base, the T-shaped stage is provided with a plurality of T-shaped long grooves arranged in sequence, and the T-shaped long grooves are used to install the fixture module, the T-shaped stage is installed in the middle of the upper surface of the base, and the T-shaped stage is used to install the workpiece to be measured.

[0009] In one embodiment, the base is made of marble; the base includes a middle platform and two side platforms, the two side platforms are symmetrically connected to both sides of the middle platform, and a plurality of T-shaped long grooves are arranged in sequence on the middle platform, and the arrangement direction of the plurality of T-shaped long grooves is parallel to the line connecting the two side platforms, and the length direction of the T-shaped long grooves is perpendicular to the arrangement direction of the plurality of T-shaped long grooves.

[0010] In one embodiment, the fixture module includes a plurality of clamping units, and the plurality of clamping units are installed in the T-shaped long slot, and the plurality of clamping units are arranged around the periphery of the workpiece to be measured; the clamping unit includes a pressure plate, a wedge column, a return spring, a first bolt and a second bolt, the first end of the pressure plate is used to press the upper surface of the workpiece to be measured, a through hole is provided in the middle of the pressure plate, the lower end bolt head of the first bolt is slidably connected to the T-shaped long slot, the upper end of the first bolt passes through the through hole and is tightened by a nut, the return spring is sleeved on the outer periphery of the first bolt, and the A limiting ring is provided on the outer circumference of the first bolt corresponding to the positions of the two ends of the return spring. The lower limiting ring abuts the upper surface of the intermediate platform, and the upper limiting ring is slidably connected to the outer circumference of the first bolt and abuts the lower end surface of the pressure plate. The lower end bolt head of the second bolt is slidably connected to the T-shaped long groove, and the upper end of the second bolt is movably connected to the wedge column. The upper end of the wedge column is embedded in the groove at the lower end of the pressure plate, and the wedge column can slide along the outer circumference of the second bolt. The outer circumference of the second bolt is threaded with a nut, and the nut is used to abut the lower end of the wedge column.

[0011] In one embodiment, the motion scanning module includes a Y-axis motion component, a Z-axis motion component and two groups of X-axis motion components. The two groups of X-axis motion components are symmetrically arranged and respectively installed on both sides of the upper end surface of the support module. The two ends of the Y-axis motion component are respectively connected to the output ends of the two groups of X-axis motion components, the Z-axis motion component is connected to the output end of the Y-axis motion component, and the nanoindentation loading and detection module is connected to the output end of the Z-axis motion component.

[0012] In one embodiment, the X-axis motion assembly includes an X-axis AC servo motor, an X-axis gear rack element, an X-axis connecting plate, and two groups of X-axis guide rail slider elements. The two groups of X-axis guide rail slider elements are parallel to each other and are mounted on the upper end of the support module through an X-axis mounting base. The X-axis connecting plate is connected to the sliders in the two groups of X-axis guide rail slider elements. The X-axis gear rack element is mounted between the two groups of X-axis guide rail slider elements. The X-axis AC servo motor is mounted on the X-axis connecting plate, and the output shaft of the X-axis AC servo motor passes through the X-axis connecting plate and is coaxially connected to the gear in the X-axis gear rack element.

[0013] The Y-axis motion assembly includes a Y-axis AC servo motor, a Y-axis gear rack element, a Y-axis connecting plate, and two groups of Y-axis guide rail slider elements. The two groups of guide rail slider elements in the Y-axis motion assembly are parallel to each other and mounted on a Y-axis mounting base. The Y-axis connecting plate is connected to the sliders in the two groups of Y-axis guide rail slider elements. The Y-axis gear rack element is mounted between the two groups of Y-axis guide rail slider elements. The Y-axis AC servo motor is mounted on the Y-axis connecting plate, and the output shaft of the Y-axis AC servo motor passes through the Y-axis connecting plate and is coaxially connected to the gear in the Y-axis gear rack element. The two ends of the Y-axis mounting base are respectively mounted on the two X-axis connecting plates.

[0014] A grating ruler is installed on one side of the X-axis mounting base and one side of the Y-axis mounting base, and limit travel switches are installed on both ends of the X-axis mounting base and both ends of the Y-axis mounting base, and the Z-axis motion component is installed on the Y-axis connecting plate;

[0015] The Z-direction motion assembly includes a voice coil motor, a Z-direction connecting block and a Z-direction fixed plate. A Z-direction mounting plate is installed on one side of the Y-direction connecting plate. The Z-direction mounting plate is installed on the side away from the Y-direction connecting plate with two Z-direction guide rails arranged side by side and extending in the vertical direction. The two ends of the Z-direction connecting block are slidably connected to the two Z-direction guide rails. The lower end of the voice coil motor is connected to the nanoindentation loading and detection module through the Z-direction fixed plate and screws, and the nanoindentation loading and detection module is connected to the Z-direction connecting block. The voice coil motor can push the nanoindentation loading and detection module to move along the Z direction.

[0016] In one embodiment, the nanoindentation loading and detection module includes a nanoindentation unit and a detection unit, the nanoindentation unit includes a first flexible hinge, an indenter column and an indenter, the detection unit includes a force sensor, a capacitive displacement sensor unit and a displacement plate, a piezoelectric stack is installed in the groove of the first flexible hinge, and a pre-tightening screw is installed at the upper end of the first flexible hinge, and the pre-tightening force of the piezoelectric stack can be adjusted by tightening the pre-tightening screw, the upper end of the first flexible hinge is connected to the voice coil motor, the lower end of the first flexible hinge is installed with the force sensor, the lower end of the force sensor is connected to the upper end of the indenter column, and the force sensor is provided with an internal thread for matching with the external thread of the indenter column, the displacement plate is pressed between the force sensor and the indenter column, the lower end of the indenter column is connected to the indenter through a locating pin, the upper part of the capacitive displacement sensor unit is connected to one side of the Z-direction connecting block through a screw, and the lower end of the capacitive displacement sensor unit extends in a direction close to the displacement plate.

[0017] In one embodiment, the pulsed eddy current nondestructive testing module includes a protective sleeve, a wedge block, a second flexible hinge, an annular piezoelectric stack and a pulsed eddy current probe unit, the second flexible hinge is sleeved on the outer periphery of the upper part of the pressure head column, and the upper end of the second flexible hinge is located at the lower end face of the displacement plate, the second flexible hinge is connected to the force sensor, the upper end of the second flexible hinge is provided with an internal thread for cooperating with the external thread of the pressure head column to adjust the preload force of the annular piezoelectric stack, the annular piezoelectric stack is coaxially sleeved on the outer periphery of the second flexible hinge, the lower end of the second flexible hinge is threadedly connected to the upper end of the protective sleeve, the protective sleeve is sleeved on the outer periphery of the lower part of the pressure head column, the wedge block is sleeved on the outer periphery of the pressure head column and is located in the protective sleeve, the pulsed eddy current probe unit is installed on the wedge block and is located in the protective sleeve, and the pulsed eddy current probe unit is arranged around the outer periphery of the pressure head column.

[0018] In one embodiment, the pulse eddy current probe unit includes a receiving coil and multiple excitation coils, the receiving coil is sleeved on the outer periphery of the pressure head column, and the multiple excitation coils are evenly arranged around the outer periphery of the receiving coil, each of the excitation coils is provided with an iron core, and the upper end of each iron core is installed on the wedge block, and the outer periphery of the pressure head column is also sleeved with a pre-tightening compression spring, the upper end of the pre-tightening compression spring is connected to the lower end of the second flexible hinge, and the lower end of the pre-tightening compression spring is connected to the upper end of the wedge block.

[0019] The present invention also provides a residual stress composite detection method based on pulsed eddy current and nanoindentation, using a residual stress composite detection device based on pulsed eddy current and nanoindentation according to any one of the above technical solutions, comprising the following steps:

[0020] S1. Use the fixture module to accurately position and clamp the workpiece to the T-stage of the support module. The parallel detection control module's industrial computer sends motion signals to the motion controller, adjusts the motion scanning module, and moves the nanoindentation loading and testing module. The pulsed eddy current probe unit of the pulsed eddy current nondestructive testing module and the surface of the workpiece remain within the working range, and the indenter of the nanoindentation loading and testing module reaches the surface of the workpiece.

[0021] S2. Use the pulsed eddy current nondestructive testing module to detect residual stress within the workpiece. The piezoelectric amplifier of the parallel detection control module sends a control signal to the annular piezoelectric stack of the pulsed eddy current nondestructive testing module, causing the second flexible hinge of the pulsed eddy current nondestructive testing module to micro-move. This adjusts the distance between the pulsed eddy current probe unit and the surface of the workpiece, causing the pulsed eddy current probe unit to move in the Z direction relative to the indenter, stopping at the point where the maximum received signal is detected.

[0022] S3. Detection of residual stress within the workpiece: A signal generator sends an excitation signal to the excitation coil of the pulsed eddy current probe unit. A differential amplifier then amplifies the received signal from the receiving coil of the pulsed eddy current probe unit. A lock-in amplifier calculates the phase between the signal generator reference signal and the received signal, reads the signal into a data acquisition card, and feeds it back to the supporting analysis and processing software of the upper industrial computer for analysis and calculation.

[0023] S4. Perform pre-contact testing. First, adjust the capacitive displacement sensor unit of the nanoindentation loading and detection module to within the measuring range. Then, the voice coil motor of the motion scanning module drives the indenter toward the surface of the workpiece being tested until the load signal collected by the force sensor of the nanoindentation loading and detection module changes suddenly. After analysis, the industrial computer sends a motion command to the voice coil motor to stop it, records the indenter's Z-axis travel, and then raises the indenter.

[0024] S5. Use nanoindentation to detect residual stress on the surface of the workpiece. Fine-tune the indentation position by using the X-axis motion component and the Y-axis motion component of the motion scanning module. Send a motion command to the voice coil motor to make the indenter approach the surface of the workpiece. The host computer triggers the command and sends a voltage drive signal to the piezoelectric stack of the nanoindentation loading and detection module through the piezoelectric amplifier to control the continuous movement of the indenter. At the same time, the force sensor monitors the load change of the indenter in real time. The load feedback signal is amplified by the charge amplifier and read into the signal acquisition card, which is then transmitted to the industrial computer. The capacitive displacement sensor unit transmits the measured displacement signal to the industrial computer. The indentation load-displacement curve of the material is obtained through calculation and analysis by the industrial computer. The specific relationship between residual stress and indentation response parameters is established from this, thereby making qualitative and quantitative detection of residual stress. The indenter is then lifted.

[0025] S6. Based on the different surface geometric morphologies of the workpiece being measured, the industrial computer sends instructions to the piezoelectric amplifiers of the motion scanning module and the parallel detection control module to perform multiple detections at different positions on the workpiece with complex geometric features, thereby achieving synchronous and in-situ test characterization of the residual stress on the surface of the workpiece being measured and its internal structure.

[0026] Compared with the prior art, the present invention has achieved the following technical effects:

[0027] The present invention provides a residual stress composite detection device and method based on pulsed eddy current and nanoindentation, wherein the clamp module is installed in the middle of the upper end of the support module, and the clamp module is used to clamp the workpiece to be measured, the motion scanning module is installed at the upper end of the support module, and the output end of the motion scanning module is connected to the nanoindentation loading and detection module, the motion scanning module can drive the nanoindentation loading and detection module to move in multiple directions, the output end of the nanoindentation loading and detection module is connected to the pulsed eddy current non-destructive testing module, the pulsed eddy current non-destructive testing module is located above the workpiece to be measured, and is used to detect the residual stress inside the workpiece to be measured, by integrating the pulsed eddy current with the nanoindentation, and coaxially combining the pulsed eddy current and nanoindentation detection probes, the degree of integration is high, and the "indentation-eddy current-scanning- The "control-fusion" multi-factor coupling optimization design and integration, and the design of an innovative series flexible hinge structure enable the nanoindentation loading and detection module and the pulsed eddy current non-destructive testing module to move relatively independently and precisely, and to freely combine multiple detection modes, to achieve synchronous and co-located test characterization of the surface and internal residual stress of metal materials. The parallel detection control module is electrically connected to the pulsed eddy current non-destructive testing module and is used to control the pulsed eddy current non-destructive testing module to adjust the distance between it and the surface of the workpiece being tested. The parallel detection control module is also electrically connected to the motion scanning module and is used to control the movement of the motion scanning module. Through the above design, a new method of pulsed eddy current and nanoindentation composite detection is adopted, which can perform continuous residual stress detection from the surface to the inside and deep into the surface, and realize the three-dimensional residual stress reconstruction modeling of metal materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 Schematic diagram of the structure of the residual stress composite detection device based on pulsed eddy current and nanoindentation in Example 1;

[0030] Figure 2 for Figure 1 The main view;

[0031] Figure 3 for Figure 1 A top view of

[0032] Figure 4 This is a front view of the Z-axis motion assembly, pulsed eddy current nondestructive testing module, and nanoindentation loading and testing module in Example 1;

[0033] Figure 5 for Figure 4 Side view of;

[0034] Figure 6 2 is a cross-sectional view of the pulsed eddy current nondestructive testing module and the nanoindentation loading and testing module in Example 1;

[0035] Figure 7 This is a structural exploded diagram of the pulsed eddy current nondestructive testing module and the nanoindentation loading and testing module in Example 1;

[0036] Figure 8 Schematic diagram of the structure of the pulsed eddy current detection unit in Example 1;

[0037] Figure 9 This is a structural exploded view of the pulsed eddy current detection unit in Example 1;

[0038] Figure 10 This is a block diagram of the control system of the residual stress composite detection method based on pulsed eddy current and nanoindentation in Example 2;

[0039] In the figure: 1- pulsed eddy current nondestructive testing module, 111- protective cover, 112- wedge block, 113- second flexible hinge, 114- annular piezoelectric stack, 115- pulsed eddy current probe unit, 1151- excitation coil, 1152- receiving coil, 1153- iron core, 116- preloaded compression spring, 2- nanoindentation loading and detection module, 211- indenter, 212- force sensor, 213- displacement plate, 214- first flexible hinge, 215- indenter column, 216- piezoelectric stack, 217- capacitive displacement sensor unit, 218- preloaded screw, 3- motion sweep Scanning module, 311-X-axis AC servo motor, 312-X-axis gear rack element, 313-X-axis guide rail slider element, 314-X-axis connecting plate, 315-grating scale, 316-X-axis mounting base, 317-voice coil motor, 318-Y-axis mounting base, 319-Y-axis guide rail slider element, 320-Y-axis connecting plate, 321-Z-axis connecting block, 322-Z-axis fixed plate, 323-limit travel switch, 4-measured workpiece, 5-fixture module, 51-clamping unit, 511-pressure plate, 512-wedge column, 513-reset spring, 6-T-type stage, 7-base. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] The purpose of the present invention is to provide a residual stress composite detection device and method based on pulsed eddy current and nanoindentation to solve the problems existing in the prior art and realize synchronous and in-situ testing of residual stress of the machined surface and sub-surface metal materials of the workpiece being tested.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] like Figures 1-9 As shown, this embodiment provides a residual stress composite detection device based on pulsed eddy current and nanoindentation, including a pulsed eddy current nondestructive testing module 1, a nanoindentation loading and detection module 2, a motion scanning module 3, a fixture module 5, a support module and a parallel detection control module. The fixture module 5 is installed in the middle of the upper end of the support module, and the fixture module 5 is used to clamp the workpiece 4 to be measured. The motion scanning module 3 is installed at the upper end of the support module, and the output end of the motion scanning module 3 is connected to the nanoindentation loading and detection module 2. The motion scanning module 3 can drive the nanoindentation loading and detection module 2 to move in multiple directions. The output end of the nanoindentation loading and detection module 2 is connected to the pulsed eddy current nondestructive testing module 1. The pulsed eddy current nondestructive testing module 1 is located above the workpiece 4 to be measured and is used to detect the residual stress inside the workpiece 4 to be measured. By integrating the pulsed eddy current with the nanoindentation, and combining the pulsed eddy current with the nanoindentation The nanoindentation detection probe is coaxially integrated with a high degree of integration, realizing the multi-factor coupling optimization design and integration of "indentation-eddy current-scanning-control-fusion", and designing an innovative series flexible hinge structure to enable the nanoindentation loading and detection module 2 and the pulsed eddy current non-destructive detection module 1 to move relatively independently and precisely, and to freely combine multiple detection modes, to achieve synchronous and co-located test characterization of the surface and internal residual stress of metal materials. The parallel detection control module is electrically connected to the pulsed eddy current non-destructive detection module 1, and is used to control the pulsed eddy current non-destructive detection module 1 to adjust the distance between it and the surface of the workpiece 4 to be measured. The parallel detection control module is also electrically connected to the motion scanning module 3, and is used to control the movement of the motion scanning module 3. Through the above design, a new method of pulsed eddy current and nanoindentation composite detection is adopted, which can perform continuous residual stress detection from the surface to the inside and deep into the surface, and realize three-dimensional residual stress reconstruction and modeling of metal materials.

[0045] Specifically, the support module includes a base 7 and a T-shaped stage 6. The base 7 is I-shaped, and the two sides of the base 7 are higher than the middle of the base 7. The T-shaped stage 6 is provided with a plurality of T-shaped long grooves arranged in sequence, and the T-shaped long grooves are used to install the fixture module 5, which is convenient for adjusting the position of the fixture module 5 and adapting to various fixture modules 5. The T-shaped stage 6 is installed in the middle of the upper surface of the base 7, and the T-shaped stage 6 is used to install the workpiece 4 to facilitate subsequent inspection of the workpiece 4.

[0046] The base 7 is made of marble; the base 7 includes a middle platform and two side platforms, the two side platforms are symmetrically connected to the two sides of the middle platform, and multiple T-shaped long grooves are arranged in sequence on the middle platform, and the arrangement direction of the multiple T-shaped long grooves is parallel to the connecting line between the two side platforms, and the length direction of the T-shaped long grooves is perpendicular to the arrangement direction of the multiple T-shaped long grooves.

[0047] The clamp module 5 includes multiple groups of clamping units 51, which are all installed in the T-shaped long slot, and the multiple groups of clamping units 51 are arranged around the outer periphery of the workpiece 4 to be measured, thereby improving the clamping stability of the workpiece 4 to be measured. The clamping units 51 are preferably four groups, thereby clamping each side of the workpiece 4 to be measured; the clamping unit 51 includes a pressure plate 511, a wedge column 512, a return spring 513, a first bolt and a second bolt. The first end of the pressure plate 511 is used to press on the upper surface of the workpiece 4 to be measured, and then the workpiece 4 to be measured is limited above the workpiece 4 to be measured by the pressure plate 511, and the workpiece 4 to be measured is pressed on the T-shaped stage 6 to avoid shaking of the workpiece 4 to be measured during the detection process, which affects the detection results. A through hole is provided in the middle of the pressure plate 511, and the lower end bolt head of the first bolt is slidably connected to the T-shaped long slot, and the upper end of the first bolt passes through the through hole and is fastened by a nut. The nut is used to abut the lower end of the wedge column 512, so that when the height of the pressure plate 511 is adjusted, the reset spring 513 can be compressed. At the same time, by tightening the nut on the second bolt and the nut on the first bolt, the workpiece 4 to be measured is fixed.

[0048] The motion scanning module 3 includes a Y-direction motion component, a Z-direction motion component and two groups of X-direction motion components. The two groups of X-direction motion components are symmetrically arranged and respectively installed on both sides of the upper end surface of the support module. The two ends of the Y-direction motion component are respectively connected to the output ends of the two groups of X-direction motion components, so that the X-direction motion component drives the Y-direction motion component to move in the X direction. The Z-direction motion component is connected to the output end of the Y-direction motion component, so that the Y-direction motion component drives the Z-direction motion component to move in the Y direction. The nanoindentation loading and detection module 2 is connected to the output end of the Z-direction motion component to realize the Z-direction movement of the nanoindentation loading and detection module 2.

[0049] The X-axis motion assembly includes an X-axis AC servo motor 311, an X-axis rack and pinion element 312, an X-axis connecting plate 314, and two sets of X-axis guide rail slider elements 313. The two sets of X-axis guide rail slider elements 313 are parallel to each other and are installed on the upper end of the support module through an X-axis mounting base 316. The X-axis connecting plate 314 is connected to the sliders in the two sets of X-axis guide rail slider elements 313, and the X-axis connecting plate 314 is supported and guided by the two sets of X-axis guide rail slider elements 313. Combined with the grating ruler 315, large-stroke closed-loop precision motion control can be achieved; the X-axis rack and pinion element 312 is installed between the two sets of X-axis guide rail slider elements 313, the X-axis AC servo motor 311 is installed on the X-axis connecting plate 314, and the output shaft of the X-axis AC servo motor 311 passes through the X-axis connecting plate 314 and is coaxially connected to the gear in the X-axis rack and pinion element 312;

[0050] The Y-axis motion assembly includes a Y-axis AC servo motor, a Y-axis rack and pinion element, a Y-axis connecting plate 320 and two groups of Y-axis guide rail slider elements 319. The two groups of guide rail slider elements in the Y-axis motion assembly are parallel to each other and mounted on the Y-axis mounting base 318. The Y-axis connecting plate 320 is connected to the sliders in the two groups of Y-axis guide rail slider elements 319, and the Y-axis connecting plate 320 is supported and guided by the two groups of Y-axis guide rail slider elements 319. Combined with the grating ruler 315, large-stroke closed-loop precision motion control can be achieved; the Y-axis rack and pinion element is installed between the two groups of Y-axis guide rail slider elements 319, the Y-axis AC servo motor is installed on the Y-axis connecting plate 320, and the output shaft of the Y-axis AC servo motor passes through the Y-axis connecting plate 320 and is coaxially connected to the gear in the Y-axis rack and pinion element. The two ends of the Y-axis mounting base 318 are respectively mounted on the two X-axis connecting plates 314 to achieve large-stroke scanning motion in the XY two-dimensional plane;

[0051] Among them, the X-guide rail slider element 313 and the Y-guide rail slider element 319 have the same structure, and both include guide rails and sliders. The sliders are slidably connected to the guide rails, and the X-direction connecting plate 314 or the Y-direction connecting plate 320 are connected to the sliders; the X-direction gear rack element 312 and the Y-direction gear rack element have the same structure, and both include racks and gears. The gears are connected to the output shafts of the X-direction AC servo motor 311 or the Y-direction AC servo motor, and the gears are meshed with the racks. Then, the gears are driven to rotate by the X-direction AC servo motor 311 or the Y-direction AC servo motor, and the gears move along the racks, thereby driving the X-direction AC servo motor 311 or the Y-direction AC servo motor to move, thereby realizing the movement of the corresponding connecting plates.

[0052] A grating ruler 315 is mounted on one side of the X-axis mounting base 316 and one side of the Y-axis mounting base 318. Limit switches 323 are mounted on both ends of the X-axis mounting base 316 and both ends of the Y-axis mounting base 318 to limit the movement of the X-axis connecting plate 314 and the Y-axis connecting plate 320, preventing them from exceeding the limit and causing connection failure, which would affect work efficiency and service life. The Z-axis motion component is mounted on the Y-axis connecting plate 320.

[0053] The Z-direction motion component includes a voice coil motor 317, a Z-direction connecting block 321 and a Z-direction fixed plate 322. A Z-direction mounting plate is installed on one side of the Y-direction connecting plate 320. The Z-direction mounting plate is installed on the side away from the Y-direction connecting plate 320. Two Z-direction guide rails are arranged side by side and extend in the vertical direction. The two ends of the Z-direction connecting block 321 are slidably connected to the two Z-direction guide rails. The lower end of the voice coil motor 317 is connected to the nanoindentation loading and detection module 2 through the Z-direction fixed plate 322 and screws, and the nanoindentation loading and detection module 2 is connected to the Z-direction connecting block 321 to realize macro-adjustment of the Z-direction spacing between the working end of the nanoindentation loading and detection module 2 and the surface of the workpiece 4 to be measured. The voice coil motor 317 can push the nanoindentation loading and detection module 2 to move along the Z direction.

[0054] The nanoindentation loading and detection module 2 includes a nanoindentation unit and a detection unit. The nanoindentation unit includes a first flexible hinge 214, an indenter column 215 and an indenter 211. The detection unit includes a force sensor 212, a capacitive displacement sensor unit 217 and a displacement measuring plate 213. A piezoelectric stack 216 is installed in the groove of the first flexible hinge 214, and a pre-tightening screw 218 is installed on the upper end of the first flexible hinge 214. The pre-tightening force of the piezoelectric stack 216 can be adjusted by tightening the pre-tightening screw 218 and pressing the piezoelectric stack 216 with the pre-tightening screw 218. The upper end of the first flexible hinge 214 is connected to a voice coil motor 317, which can drive the piezoelectric stack 216 to extend through the voice coil motor 317, thereby causing the piezoelectric stack 216 to drive the first The flexible hinge 214 deforms to drive the pressure head 211 to move toward the direction close to the workpiece surface. A force sensor 212 is installed at the lower end of the first flexible hinge 214. The lower end of the force sensor 212 is connected to the upper end of the pressure head column 215, and the force sensor 212 is provided with an internal thread for cooperating with the external thread of the pressure head column 215. The force sensor 212 is used to collect the load signal of the pressure head 211 in real time. The displacement measuring plate 213 is pressed between the force sensor 212 and the pressure head column 215. The lower end of the pressure head column 215 is connected to the pressure head 211 through a positioning pin. The upper part of the capacitive displacement sensor unit 217 is connected to one side of a Z-direction connecting block 321 through a screw, and the lower end of the capacitive displacement sensor unit 217 extends toward the direction close to the displacement measuring plate 213.

[0055] The pulsed eddy current nondestructive testing module 1 includes a protective sleeve 111, a wedge block 112, a second flexible hinge 113, an annular piezoelectric stack 114 and a pulsed eddy current probe unit 115. The second flexible hinge 113 is sleeved on the outer periphery of the upper part of the pressure head column 215, and the upper end of the second flexible hinge 113 is located at the lower end surface of the displacement measuring plate 213. The second flexible hinge 113 is connected to the force sensor 212. The upper end of the second flexible hinge 113 is provided with an internal thread for cooperating with the external thread of the pressure head column 215 to adjust the pre-tightening force of the annular piezoelectric stack 114. At the same time, the internal thread of the pressure head column 215 is fixed with the external thread of the force sensor 212 to realize macro / micro hybrid drive. The annular piezoelectric stack 114 is coaxially sleeved on the outer periphery of the second flexible hinge 113. The second flexible hinge 113 is connected to the force sensor 212. 3 is threadedly connected to the upper end of the protective sleeve 111, and when a control signal is sent to the annular piezoelectric stack 114, the annular piezoelectric stack 114 can stretch and drive the second flexible hinge 113 to move slightly, and the second flexible hinge 113 drives the pulsed eddy current probe unit 115 to move in the Z direction relative to the pressure head 211 to reach the maximum receiving signal. The protective sleeve 111 is sleeved on the outer periphery of the lower part of the pressure head column 215, and the wedge block 112 is sleeved on the outer periphery of the pressure head column 215 and is located in the protective sleeve 111, and the wedge block 112 is used to achieve stable installation of the pulsed eddy current probe unit 115, the pulsed eddy current probe unit 115 is installed on the wedge block 112 and is located in the protective sleeve 111, and the pulsed eddy current probe unit 115 is arranged around the outer periphery of the pressure head column 215.

[0056] The pulsed eddy current probe unit 115 and the nanoindentation unit are coaxially arranged, and the distance between the pulsed eddy current probe unit 115 and the surface of the workpiece 4 to be measured is measured through the real-time voltage-distance relationship of the annular piezoelectric stack 114. The position of the pulsed eddy current probe unit 115 is closed-loop controlled to suppress the lift-off effect and realize residual stress detection on the processing surface / interior.

[0057] The pulse eddy current probe unit 115 includes a receiving coil 1152 and multiple excitation coils 1151. The receiving coil 1152 is sleeved on the outer periphery of the pressure head column 215. The multiple excitation coils 1151 are evenly arranged around the outer periphery of the receiving coil 1152 and are coaxially positioned and assembled with the pressure head 211. Each excitation coil 1151 is provided with an iron core 1153. The upper end of each iron core 1153 is installed on the wedge block 112. The outer periphery of the pressure head column 215 is also sleeved with a pre-tightening compression spring 116. The upper end of the pre-tightening compression spring 116 is connected to the lower end of the second flexible hinge 113, and the lower end of the pre-tightening compression spring 116 is connected to the upper end of the wedge block 112. Through the above design, the pulse eddy current probe unit 115 adopts a non-contact pulse eddy current detection mode, which can realize the evaluation of internal residual stress of the material.

[0058] Example 2

[0059] like Figure 10As shown, this embodiment provides a residual stress composite detection method based on pulsed eddy current and nanoindentation, using the residual stress composite detection device based on pulsed eddy current and nanoindentation in Example 1, including the following steps:

[0060] S1. Use the fixture module 5 to accurately position and clamp the workpiece 4 to the T-stage 6 of the support module. The industrial computer of the parallel detection control module sends a motion signal to the motion controller, adjusts the motion scanning module 3, and moves the nanoindentation loading and detection module 2 over a large range. The pulsed eddy current probe unit 115 of the pulsed eddy current nondestructive testing module 1 and the surface of the workpiece 4 remain within the working range, and the indenter 211 of the nanoindentation loading and detection module 2 reaches the surface of the workpiece 4.

[0061] S2. The pulsed eddy current nondestructive testing module 1 is used to detect the residual stress inside the workpiece 4. The piezoelectric amplifier of the parallel detection control module sends a control signal to the annular piezoelectric stack 114 of the pulsed eddy current nondestructive testing module 1, causing the second flexible hinge 113 of the pulsed eddy current nondestructive testing module 1 to produce a micro-motion. The distance between the pulsed eddy current probe unit 115 and the surface of the workpiece 4 is adjusted, and the pulsed eddy current probe unit 115 moves in the Z direction relative to the indenter 211. The movement stops when the maximum received signal is reached.

[0062] S3. Detection of residual stress within the workpiece 4: A signal generator with controllable frequency and phase sequence sends an excitation signal to the excitation coil 1151 of the pulsed eddy current probe unit 115. A differential amplifier is then used to amplify the received signal from the receiving coil 1152 of the pulsed eddy current probe unit 115. The phases of the signal generator reference signal and the received signal are calculated using a lock-in amplifier, read into a data acquisition card, and fed back to the supporting analysis and processing software of the upper industrial computer for analysis and calculation.

[0063] S4. Perform pre-contact testing. First, adjust the capacitive displacement sensor unit 217 of the nanoindentation loading and detection module 2 to within the measuring range. Then, the voice coil motor 317 of the motion scanning module 3 drives the indenter 211 toward the surface of the workpiece 4 to be measured until the load signal collected by the force sensor 212 of the nanoindentation loading and detection module 2 changes suddenly. After analysis, the industrial computer sends a motion command to the voice coil motor 317 to stop it, records the Z-axis travel of the indenter 211, and then lifts the indenter 211.

[0064] S5. The residual stress on the surface of the workpiece 4 is detected by the nanoindentation method. The X-axis motion component and the Y-axis motion component of the motion scanning module 3 are used to fine-tune the indentation position, and a motion instruction is sent to the voice coil motor 317 to make the indenter 211 approach the surface of the workpiece 4. The host computer triggers the instruction to send a voltage drive signal to the piezoelectric stack 216 of the nanoindentation loading and detection module 2 through the piezoelectric amplifier to control the continuous movement of the indenter 211. At the same time, the force sensor 212 monitors the load change of the indenter 211 in real time. The load feedback signal is amplified by the charge amplifier and read into the signal acquisition card, and then transmitted to the industrial computer. The capacitive displacement sensor unit 217 transmits the measured displacement signal to the industrial computer. The indentation load-displacement curve of the material is obtained through calculation and analysis by the industrial computer, and the specific relationship between the residual stress and the indentation response parameter is established, thereby making qualitative and quantitative detection of the residual stress, and then the indenter 211 is lifted;

[0065] S6. According to the different surface geometric morphologies of the workpiece 4 to be measured, the industrial computer sends instructions to the piezoelectric amplifier of the motion scanning module 3 and the parallel detection control module to carry out multiple detections at different positions on the workpiece 4 to be measured with complex geometric features, thereby realizing synchronous and in-situ test characterization of the residual stress on the surface of the workpiece 4 to be measured and its internal structure.

[0066] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A residual stress composite detection device based on pulsed eddy current and nanoindentation, characterized by: It includes a pulsed eddy current nondestructive testing module, a nanoindentation loading and detection module, a motion scanning module, a fixture module, a support module and a parallel detection control module. The fixture module is installed in the middle of the upper end of the support module, and the fixture module is used to clamp the workpiece to be measured. The motion scanning module is installed at the upper end of the support module, and the output end of the motion scanning module is connected to the nanoindentation loading and detection module. The motion scanning module can drive the nanoindentation loading and detection module to move in multiple directions. The output end of the nanoindentation loading and detection module is connected to the pulsed eddy current nondestructive testing module. The pulsed eddy current nondestructive testing module is located above the workpiece to be measured and is used to detect the residual stress inside the workpiece to be measured. The parallel detection control module is electrically connected to the pulsed eddy current nondestructive testing module and is used to control the pulsed eddy current nondestructive testing module to adjust the distance between it and the surface of the workpiece to be measured. The parallel detection control module is also electrically connected to the motion scanning module and is used to control the movement of the motion scanning module. The nanoindentation loading and detection module includes a nanoindentation unit and a detection unit. The nanoindentation unit includes a first flexible hinge, an indenter column and an indenter. The detection unit includes a force sensor, a capacitive displacement sensor unit and a displacement plate. A piezoelectric stack is installed in the groove of the first flexible hinge. The force sensor is installed at the lower end of the first flexible hinge. The lower end of the force sensor is connected to the upper end of the indenter column, and the displacement plate is pressed between the force sensor and the indenter column. The lower end of the indenter column is connected to the indenter via a positioning pin. The pulsed eddy current nondestructive testing module includes a protective sleeve, a wedge block, a second flexible hinge, an annular piezoelectric stack and a pulsed eddy current probe unit. The second flexible hinge is sleeved on the outer periphery of the upper part of the pressure head column, and the upper end of the second flexible hinge is located at the lower end face of the displacement plate. The second flexible hinge is connected to the force sensor. The annular piezoelectric stack is coaxially sleeved on the outer periphery of the second flexible hinge. The lower end of the second flexible hinge is threadedly connected to the upper end of the protective sleeve. The protective sleeve is sleeved on the outer periphery of the lower part of the pressure head column. The wedge block is sleeved on the outer periphery of the pressure head column and is located in the protective sleeve. The pulsed eddy current probe unit is installed on the wedge block and is located in the protective sleeve, and the pulsed eddy current probe unit is arranged around the outer periphery of the pressure head column.

2. The residual stress composite detection device based on pulsed eddy current and nanoindentation according to claim 1 is characterized in that: The support module includes a base and a T-shaped stage. The base is I-shaped, and the two sides of the base are higher than the middle of the base. The T-shaped stage is provided with a plurality of T-shaped long grooves arranged in sequence, and the T-shaped long grooves are used to install the fixture module. The T-shaped stage is installed in the middle of the upper surface of the base, and the T-shaped stage is used to install the workpiece to be measured.

3. The residual stress composite detection device based on pulsed eddy current and nanoindentation according to claim 2 is characterized in that: The base is made of marble; the base includes a middle platform and two side platforms, the two side platforms are symmetrically connected to the two sides of the middle platform, and multiple T-shaped long grooves are arranged in sequence on the middle platform, and the arrangement direction of the multiple T-shaped long grooves is parallel to the connecting line between the two side platforms, and the length direction of the T-shaped long grooves is perpendicular to the arrangement direction of the multiple T-shaped long grooves.

4. The residual stress composite detection device based on pulsed eddy current and nanoindentation according to claim 3 is characterized in that: The clamp module includes multiple groups of clamping units, multiple groups of the clamping units are installed in the T-shaped long slot, and multiple groups of the clamping units are arranged around the periphery of the workpiece to be measured; the clamping unit includes a pressure plate, a wedge column, a return spring, a first bolt and a second bolt, the first end of the pressure plate is used to press the upper surface of the workpiece to be measured, the middle part of the pressure plate is provided with a through hole, the lower end bolt head of the first bolt is slidably connected to the T-shaped long slot, the upper end of the first bolt passes through the through hole and is tightened by a nut, the return spring is sleeved on the outer periphery of the first bolt, and the first bolt A limiting ring is provided at each position corresponding to the two ends of the return spring on the outer periphery. The lower limiting ring abuts the upper surface of the intermediate platform, and the upper limiting ring is slidably connected to the outer periphery of the first bolt and abuts the lower end surface of the pressure plate. The lower end bolt head of the second bolt is slidably connected to the T-shaped long groove, and the upper end of the second bolt is movably connected to the wedge column. The upper end of the wedge column is embedded in the groove at the lower end of the pressure plate, and the wedge column can slide along the outer periphery of the second bolt. The outer periphery of the second bolt is threaded with a nut, and the nut is used to abut the lower end of the wedge column.

5. The residual stress composite detection device based on pulsed eddy current and nanoindentation according to claim 1 is characterized in that: The motion scanning module includes a Y-axis motion component, a Z-axis motion component and two groups of X-axis motion components. The two groups of X-axis motion components are symmetrically arranged and respectively installed on both sides of the upper end surface of the support module. The two ends of the Y-axis motion component are respectively connected to the output ends of the two groups of X-axis motion components, the Z-axis motion component is connected to the output end of the Y-axis motion component, and the nanoindentation loading and detection module is connected to the output end of the Z-axis motion component.

6. The residual stress composite detection device based on pulsed eddy current and nanoindentation according to claim 5 is characterized in that: The X-direction motion assembly includes an X-direction AC servo motor, an X-direction gear rack element, an X-direction connecting plate, and two groups of X-direction guide rail slider elements. The two groups of X-direction guide rail slider elements are parallel to each other and are mounted on the upper end of the support module through an X-direction mounting base. The X-direction connecting plate is connected to the sliders in the two groups of X-direction guide rail slider elements. The X-direction gear rack element is mounted between the two groups of X-direction guide rail slider elements. The X-direction AC servo motor is mounted on the X-direction connecting plate, and the output shaft of the X-direction AC servo motor passes through the X-direction connecting plate and is coaxially connected to the gear in the X-direction gear rack element. The Y-axis motion assembly includes a Y-axis AC servo motor, a Y-axis gear rack element, a Y-axis connecting plate, and two groups of Y-axis guide rail slider elements. The two groups of guide rail slider elements in the Y-axis motion assembly are parallel to each other and mounted on a Y-axis mounting base. The Y-axis connecting plate is connected to the sliders in the two groups of Y-axis guide rail slider elements. The Y-axis gear rack element is mounted between the two groups of Y-axis guide rail slider elements. The Y-axis AC servo motor is mounted on the Y-axis connecting plate, and the output shaft of the Y-axis AC servo motor passes through the Y-axis connecting plate and is coaxially connected to the gear in the Y-axis gear rack element. The two ends of the Y-axis mounting base are respectively mounted on the two X-axis connecting plates. A grating ruler is installed on one side of the X-axis mounting base and one side of the Y-axis mounting base, and limit travel switches are installed on both ends of the X-axis mounting base and both ends of the Y-axis mounting base, and the Z-axis motion component is installed on the Y-axis connecting plate; The Z-direction motion assembly includes a voice coil motor, a Z-direction connecting block and a Z-direction fixed plate. A Z-direction mounting plate is installed on one side of the Y-direction connecting plate. The Z-direction mounting plate is installed on the side away from the Y-direction connecting plate with two Z-direction guide rails arranged side by side and extending in the vertical direction. The two ends of the Z-direction connecting block are slidably connected to the two Z-direction guide rails. The lower end of the voice coil motor is connected to the nanoindentation loading and detection module through the Z-direction fixed plate and screws, and the nanoindentation loading and detection module is connected to the Z-direction connecting block. The voice coil motor can push the nanoindentation loading and detection module to move along the Z direction.

7. The residual stress composite detection device based on pulsed eddy current and nanoindentation according to claim 6 is characterized in that: A pre-tightening screw is installed at the upper end of the first flexible hinge, and the pre-tightening force of the piezoelectric stack can be adjusted by tightening the pre-tightening screw. The upper end of the first flexible hinge is connected to the voice coil motor. The force sensor is provided with an internal thread for cooperating with the external thread of the pressure head column. The upper part of the capacitive displacement sensor unit is connected to one side of the Z-direction connecting block by a screw, and the lower end of the capacitive displacement sensor unit extends in a direction close to the displacement measuring plate.

8. The residual stress composite detection device based on pulsed eddy current and nanoindentation according to claim 7 is characterized in that: The upper end of the second flexible hinge is provided with an internal thread for cooperating with the external thread of the pressure head column to adjust the pre-tightening force of the annular piezoelectric stack.

9. The residual stress composite detection device based on pulsed eddy current and nanoindentation according to claim 8, characterized in that: The pulse eddy current probe unit includes a receiving coil and multiple excitation coils. The receiving coil is sleeved on the outer circumference of the pressure head column. The multiple excitation coils are evenly arranged around the outer circumference of the receiving coil. Each excitation coil is provided with an iron core. The upper end of each iron core is installed on the wedge block. The outer circumference of the pressure head column is also sleeved with a pre-tightening compression spring. The upper end of the pre-tightening compression spring is connected to the lower end of the second flexible hinge, and the lower end of the pre-tightening compression spring is connected to the upper end of the wedge block.

10. A residual stress composite detection method based on pulsed eddy current and nanoindentation, characterized by: The residual stress composite detection device based on pulsed eddy current and nanoindentation according to any one of claims 1 to 9 comprises the following steps: S1. Use the fixture module to accurately position and clamp the workpiece to the T-stage of the support module. The parallel detection control module's industrial computer sends motion signals to the motion controller, adjusts the motion scanning module, and moves the nanoindentation loading and testing module. The pulsed eddy current probe unit of the pulsed eddy current nondestructive testing module and the surface of the workpiece remain within the working range, and the indenter of the nanoindentation loading and testing module reaches the surface of the workpiece. S2. Use the pulsed eddy current nondestructive testing module to detect residual stress within the workpiece. The piezoelectric amplifier of the parallel detection control module sends a control signal to the annular piezoelectric stack of the pulsed eddy current nondestructive testing module, causing the second flexible hinge of the pulsed eddy current nondestructive testing module to micro-move. This adjusts the distance between the pulsed eddy current probe unit and the surface of the workpiece, causing the pulsed eddy current probe unit to move in the Z direction relative to the indenter, stopping at the point where the maximum received signal is detected. S3. Detection of residual stress within the workpiece: A signal generator sends an excitation signal to the excitation coil of the pulsed eddy current probe unit. A differential amplifier then amplifies the received signal from the receiving coil of the pulsed eddy current probe unit. A lock-in amplifier calculates the phase between the signal generator reference signal and the received signal, reads the signal into a data acquisition card, and feeds it back to the supporting analysis and processing software of the upper industrial computer for analysis and calculation. S4. Perform pre-contact testing. First, adjust the capacitive displacement sensor unit of the nanoindentation loading and detection module to within the measuring range. Then, the voice coil motor of the motion scanning module drives the indenter toward the surface of the workpiece being tested until the load signal collected by the force sensor of the nanoindentation loading and detection module changes suddenly. After analysis, the industrial computer sends a motion command to the voice coil motor to stop it, records the indenter's Z-axis travel, and then raises the indenter. S5. Use nanoindentation to detect residual stress on the surface of the workpiece. Fine-tune the indentation position by using the X-axis motion component and the Y-axis motion component of the motion scanning module. Send a motion command to the voice coil motor to make the indenter approach the surface of the workpiece. The host computer triggers the command and sends a voltage drive signal to the piezoelectric stack of the nanoindentation loading and detection module through the piezoelectric amplifier to control the continuous movement of the indenter. At the same time, the force sensor monitors the load change of the indenter in real time. The load feedback signal is amplified by the charge amplifier and read into the signal acquisition card, which is then transmitted to the industrial computer. The capacitive displacement sensor unit transmits the measured displacement signal to the industrial computer. The indentation load-displacement curve of the material is obtained through calculation and analysis by the industrial computer. The specific relationship between residual stress and indentation response parameters is established from this, thereby making qualitative and quantitative detection of residual stress. The indenter is then lifted. S6. Based on the different surface geometric morphologies of the workpiece being measured, the industrial computer sends instructions to the piezoelectric amplifiers of the motion scanning module and the parallel detection control module to perform multiple detections at different positions on the workpiece with complex geometric features, thereby achieving synchronous and in-situ test characterization of the residual stress on the surface of the workpiece being measured and its internal structure.

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