An ultrasonic detection system and method for residual stress of non-metallic materials

Abstract

The present invention provides an ultrasonic detection system and method for residual stress of non-metallic materials. The ultrasonic detection system includes an ultrasonic signal generator-receiver, an oscilloscope, an ultrasonic transmitting probe, and an ultrasonic receiving probe. The ultrasonic signal generator-receiver is connected to the ultrasonic transmitting probe through a first probe connection line, the input end is connected to the ultrasonic receiving probe through a second probe connection line, and the synchronization end is connected to the oscilloscope through a first signal line. It further includes a calibration component and a measurement component. The calibration component includes a left slide rail and a right slide rail, and two sets of calibration probe components are arranged between the left slide rail and the right slide rail. The measurement component includes a support arm and a main slide rail, and the support arm is connected to the main slide rail. Two sets of measurement probe components are arranged on the lower side of the main slide rail. The device of the present invention can realize the ultrasonic critically refracted longitudinal wave method for detecting the residual stress of non-metallic materials, can adapt to non-metallic parts to be measured with various residual stress distribution situations, and can meet the requirements of various detection area lengths.

Description

Technical Field

[0001] The present invention relates to the technical field of residual stress detection, and particularly to an ultrasonic detection system and method for residual stress of non-metallic materials. Background Art

[0002] Residual stress detection is divided into non-destructive measurement methods and destructive measurement methods. Among them, non-destructive measurement methods measure the changes of physical constants (such as lattice constants) inside materials in the stress field through physical optics and nuclear physics technologies, and indirectly calculate the residual stress values inside the object. It is mainly divided into neutron diffraction method, synchrotron radiation method, magnetic particle method, X-ray diffraction method, ultrasonic detection method, etc. The neutron diffraction method has a long measurement time, a weak neutron source intensity, high construction and operation costs of the neutron source, and cannot be measured in real time on-site, making it difficult to be applied to actual production detection; portable magnetic particle method for residual stress measurement is only applicable to small-area measurement, with very low efficiency and poor repeatability; X-ray diffraction method has weak penetration ability, can only non-destructively measure surface stress, and the measurement results are greatly affected by the surface state of the workpiece to be measured; ultrasonic detection method has relatively strong penetration ability for most media, and can reach several meters in some metal materials. In addition, ultrasonic detection instruments can be portable to the outdoor or on-site for use, have no radiation, are safe to operate, can measure stress, detect internal defects of specimens, and can also be used for high-precision thickness measurement, etc. Therefore, it is one of the most promising technologies in the development direction of non-destructive detection of residual stress.

[0003] Measuring residual stress by ultrasonic method is based on the linear relationship between ultrasonic wave velocity and material stress, and this relationship is the acoustoelastic effect manifested within the elastic limit of the material. Based on the acoustoelastic theory, study the relationship between the propagation velocity and direction of ultrasonic waves and stress, explore the sensitivity of different types of ultrasonic waves, and analyze the generation principle of the critically refracted longitudinal wave (L CR wave). When the L CR wave propagates along the surface layer of the specimen, it has high sensitivity to internal stress, fast propagation speed, small attenuation, and relatively simple signal analysis and positioning, and is very suitable for the detection of residual stress.

[0004] At present, certain research results have been achieved in detecting residual stress by ultrasonic method. Patent CN201610200729.2, based on the critically refracted longitudinal wave method, corrects the influence of the microstructure differences in the weld area, heat-affected area, and base metal area of the weldment to be measured on the ultrasonic residual stress test. However, due to the limitation of the low propagation velocity of ultrasonic waves in non-metallic materials, using this conventional structure of acoustic wedge block, the critically refracted longitudinal wave cannot be excited in non-metallic materials, so the ultrasonic critically refracted longitudinal wave method for detecting residual stress in non-metallic materials cannot be carried out.

[0005] How to enable the acoustic wedge block to excite the critically refracted longitudinal wave in non-metallic materials remains an urgent problem to be solved. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies of the prior art and provide an ultrasonic detection system and method for residual stress of non-metallic materials, so as to solve the problem that the critical refraction longitudinal wave cannot be excited in non-metallic materials by using a sound wedge block with a conventional structure, resulting in the inability to detect the residual stress of non-metallic materials by the ultrasonic critical refraction longitudinal wave method.

[0007] An ultrasonic detection system for residual stress of non-metallic materials provided by the present invention includes an ultrasonic signal generating and receiving instrument with a power amplification function, an oscilloscope, an ultrasonic transmitting probe and an ultrasonic receiving probe. The output end of the ultrasonic signal generating and receiving instrument is connected to the ultrasonic transmitting probe through a first probe connecting wire, the input end of the ultrasonic signal generating and receiving instrument is connected to the ultrasonic receiving probe through a second probe connecting wire, and the synchronization end of the ultrasonic signal generating and receiving instrument is connected to the input end of the oscilloscope through a first signal wire. The system also includes a calibration component and a measurement component;

[0008] The calibration component includes a left slide rail and a right slide rail placed in parallel, and two groups of calibration probe assemblies are arranged between the left slide rail and the right slide rail;

[0009] The calibration probe assembly includes a U-shaped block perpendicular to the left slide rail and the right slide rail, and both sides of the U-shaped block are slidably connected to the left slide rail and the right slide rail respectively;

[0010] A square box body parallel to the inner bottom surface of the U-shaped groove of the U-shaped block is arranged in the U-shaped groove of the U-shaped block. A convex cover body is integrally arranged at the upper end of the square box body, and a water film is arranged at the lower end. The inside of the convex cover body is hollow, and a containing cavity is formed between the convex cover body and the lower end of the square box body. The water film is located above the inner bottom surface of the U-shaped block, and the space between the water film and the inner bottom surface of the U-shaped block is used for the specimen block to pass through. The specimen block is a non-metallic material specimen to be tested with zero residual stress. A first fastening bolt is arranged through the U-shaped block along the central axis direction, and the first fastening bolt is threadedly connected to the U-shaped block for tightly fitting the upper surface of the specimen block with the water film;

[0011] On the first side of the convex cover of one of the calibration probe assemblies, a first through hole is provided; on the second side, an A water inlet is provided; on the third side, an A water outlet is provided. On the fourth side of the convex cover of the other calibration probe assembly, a second through hole is provided; on the second side, an A water inlet is provided; on the third side, an A water outlet is provided. The first side and the fourth side are two opposite and facing sides. The first through hole is used to install the ultrasonic transmitting probe, and the second through hole is used to install the ultrasonic receiving probe. And the complementary angles of the axes of the first through hole and the second through hole with the included angle of the square box body are both the first critical angle of the non-metallic material to be measured.

[0012] The actual measurement assembly includes a support arm and a main slide rail, and the support arm is connected to the main slide rail. Two groups of actual measurement probe assemblies are provided on the lower side of the main slide rail.

[0013] The actual measurement probe assembly includes a slider. The upper end of the slider is slidably connected to the main slide rail, and the lower end is provided with a nozzle and is rotatably connected to the first end of the nozzle. A strip-shaped through hole is provided on the main slide rail along the sliding direction of the slider, and an internal thread hole is provided at the upper end of the slider.

[0014] The first end of the nozzle is provided with a B water outlet, the second end is provided with a B water inlet and a notch facing the B water outlet. The notches in the two groups of actual measurement probe assemblies are respectively used to install the ultrasonic transmitting probe and the ultrasonic receiving probe. A second fastening bolt is penetrated through the strip-shaped through hole, and the second fastening bolt is matched and connected with the internal thread hole for fastening the slider on the main slide rail.

[0015] Preferably, a third group of the calibration probe assemblies is further provided between the left slide rail and the right slide rail. This third group of calibration probe assemblies is located between the two groups of calibration probe assemblies. On the fourth side of the convex cover of the third group of calibration probe assemblies, the second through hole is provided; on the second side, the A water inlet is provided; on the third side, the A water outlet is provided.

[0016] A third group of the actual measurement probe assemblies is further provided on the lower side of the main slide rail. This third group of actual measurement probe assemblies is located between the two groups of actual measurement probe assemblies. The ultrasonic receiving probe is installed in the notch of the third group of actual measurement probe assemblies.

[0017] Preferably, the convex cover is a hollow trapezoidal platform. The axis of the A water inlet is perpendicular to the second side, and the axis of the A water outlet is perpendicular to the third side. The axis of the first through hole is perpendicular to the first side, and the axis of the second through hole is perpendicular to the fourth side. And the acute included angles between the first side and the fourth side and the square box body are both the first critical angle of the non-metallic material to be measured.

[0018] Preferably, the nozzle is a Y-shaped nozzle. There are two B water inlets at the second end of the nozzle. The notch is centered between the two B water inlets. The two B water inlets are symmetrically located on both sides above the B water outlet at the first end of the nozzle.

[0019] Preferably, sliding shafts are arranged on both sides of the U-shaped block. Both the left slide rail and the right slide rail are rectangular strip plates provided with continuous inner through holes along the side length direction. One end of the sliding shaft is located in the continuous inner through hole, and its diameter matches that of the continuous inner through hole.

[0020] Preferably, both the ultrasonic transmitting probe and the ultrasonic receiving probe are multi-chip combined probes, and each chip corresponds to a different frequency.

[0021] Preferably, the ultrasonic detection system further includes a computer, and the computer is connected to the output end of the oscilloscope through a second signal line.

[0022] Another object of the present invention is to provide a method for ultrasonic detection of residual stress in non-metallic materials. Using the above ultrasonic detection system for residual stress in non-metallic materials, the steps are as follows:

[0023] S1. According to the determined detection area of the non-metallic part to be measured, determine the detection frequency f of the ultrasonic transmitting probe and the ultrasonic receiving probe i and detection parameters such as the spacing, the filtering bandwidth of the oscilloscope, and the ultrasonic excitation voltage of the ultrasonic signal generator-receiver. Set the ultrasonic signal generator-receiver and the oscilloscope according to each detection parameter, adjust the spacing of the calibration probe assembly and the spacing of the actual measurement probe assembly, and make the spacing of the calibration probe assembly and the spacing of the actual measurement probe assembly the same;

[0024] S2. Install the ultrasonic transmitting probe into the first through hole, and install the ultrasonic receiving probe into the second through hole; place the specimen block on the calibration probe assembly, rotate the first fastening bolt to fix the specimen block, inject a stable water flow into each A water inlet to fill the accommodation cavity with water, so that the ultrasonic transmitting probe and the ultrasonic receiving probe are stably coupled to the calibration area of the specimen block; fix both ends of the specimen block on the clamping device of the tensile machine;

[0025] Start the ultrasonic signal generator-receiver, and obtain the ultrasonic critically refracted longitudinal wave propagation time t0 of the specimen block according to the waveform information of the oscilloscope;

[0026] S3. Within the material elastic limit of the non-metallic part to be measured, conduct a tensile test on the specimen block. The tensile test includes at least ten increasing tensile stress values σ nObtain the ultrasonic critically refracted longitudinal wave propagation time \(t\) of each of the specimen blocks at each of the tensile stress values n ;

[0027] Calculate the acoustic time difference \(\Delta t\) of the ultrasonic critically refracted longitudinal wave of the specimen block at different tensile stress values and the change \(\Delta\sigma\) in the tensile stress output by the tensile machine, plot the coordinate graph of the tensile stress value and the acoustic time difference, perform linear fitting on the data, and obtain the reciprocal \(k\) of the slope of the straight line. \(k\) is the stress coefficient of the non-metallic material to be measured;

[0028] S4, respectively install the ultrasonic transmitting probe and the ultrasonic receiving probe into each notch, place the non-metallic part to be measured under the actual measurement assembly and make its detection area located between the ultrasonic transmitting probe and the ultrasonic receiving probe, rotate the second fastening bolt to fasten the slider on the main slide rail, and rotate each nozzle to adjust the incident angle of the ultrasonic transmitting probe and the ultrasonic receiving probe to the first critical angle of the non-metallic material to be measured; inject stable water flow into each of the B water inlets to fill the nozzles with water;

[0029] S5, according to the waveform information of the oscilloscope, obtain the ultrasonic critically refracted longitudinal wave propagation time \(t\) of the non-metallic part to be measured, and calculate the residual stress \(\sigma\) of the detection area of the non-metallic part to be measured according to the ultrasonic critically refracted longitudinal wave propagation time \(t_0\) of the specimen block and the stress coefficient \(k\) of the non-metallic material to be measured i 。

[0030] Preferably, it further includes the steps:

[0031] S6, change the frequencies of the ultrasonic transmitting probe and the ultrasonic receiving probe to \(f\) j , according to the waveform information of the oscilloscope, obtain the ultrasonic critically refracted longitudinal wave propagation time \(t\) of the non-metallic part to be measured j , and calculate the residual stress \(\sigma\) of the detection area of the non-metallic part to be measured according to the ultrasonic critically refracted longitudinal wave propagation time \(t_0\) of the specimen block and the stress coefficient \(k\) of the non-metallic material to be measured j ;

[0032] S7, according to the residual stresses \(\sigma\) i and \(\sigma\) j , calculate the residual stress depth gradient \(\sigma\) i-j of the non-metallic part to be measured

[0033] Preferably, the formula for calculating the residual stress \(\sigma\) i of the detection area of the non-metallic part to be measured is:

[0034] \(\sigma\) i -\(\sigma_0 = k(t - t_0)\);

[0035] In the formula, σ0 is the residual stress of the specimen block, with the unit of MPa; t0 is the propagation time of the ultrasonic critically refracted longitudinal wave of the specimen block, with the unit of ns; t is the propagation time of the ultrasonic critically refracted longitudinal wave of the non-metallic part to be measured, with the unit of ns; t - t0 = Δt, which is the change in propagation time (also called the time difference), with the unit of ns; k is the stress coefficient of the non-metallic material to be measured.

[0036] Further preferably, the residual stress depth gradient σ of the non-metallic part to be measured i-j is calculated by the formula:

[0037]

[0038] In the formula, σ i-j is the residual stress within the depth range D of the non-metallic part to be measured, with the unit of MPa; f i-j and f i are the detection frequencies of the ultrasonic transmitting probe and the ultrasonic receiving probe, with the unit of MHz, and the corresponding detected residual stresses of the non-metallic part to be measured are σ j and σ i and σ j .

[0039] It can be seen from the above technical solutions that the present invention has the following advantages:

[0040] An ultrasonic detection system for the residual stress of a non-metallic material provided by the present invention forms a receiving cavity for accommodating the water coupling agent by arranging the square box body and the convex cover body in the calibration assembly, and makes the incident angles of the ultrasonic transmitting probe and the ultrasonic receiving probe be the first critical angle of the non-metallic material to be measured through the settings of the first through hole and the second through hole; in the actual measurement assembly, by arranging the nozzle, the nozzle is rotatably connected to the slider, and the incident angles of the ultrasonic transmitting probe and the ultrasonic receiving probe installed on the nozzle can be adjusted to the first critical angle of the non-metallic material to be measured; thus, in the calibration assembly and the actual measurement assembly, stable water coupling between the ultrasonic transmitting probe and the ultrasonic receiving probe and the surface of the specimen block or the non-metallic part to be measured can be achieved, enabling the ultrasonic longitudinal wave to enter the specimen block or the non-metallic part to be measured after propagating in the water coupling agent, and increasing the wave speed of the ultrasonic longitudinal wave propagating in the specimen block or the non-metallic part to be measured. In this way, according to Snell's law, the ultrasonic longitudinal wave can propagate in the specimen block or the non-metallic part to be measured and can excite the critically refracted longitudinal wave (L CR wave), and then the stress coefficient k of the specimen block and the ultrasonic propagation time t0 corresponding to zero stress can be detected through the calibration assembly, and the ultrasonic propagation time t of the ultrasonic longitudinal wave in the non-metallic part to be measured can be detected through the actual measurement assembly. Finally, the residual stress value σ corresponding to the ultrasonic propagation time t can be calculated. i, the ultrasonic critically refracted longitudinal wave method for detecting residual stress in non-metallic materials is realized, solving the problem that the critically refracted longitudinal wave cannot be excited in non-metallic materials by using a sound wedge block with a conventional structure, resulting in the inability to detect the residual stress in non-metallic materials by the ultrasonic critically refracted longitudinal wave method.

[0041] The calibration probe assembly in the calibration component is slidably connected to the left slide rail and the right slide rail through the U-shaped block, and the measured probe assembly in the measurement component is slidably connected to the main slide rail through the slider, so that the distance between the ultrasonic transmitting probe and the ultrasonic receiving probe can be adjusted according to the residual stress distribution of the non-metallic part to be measured and the need for the length of the detection area. It can adapt to non-metallic parts with various residual stress distributions, meet the requirements of various detection area lengths, realize the ultrasonic critically refracted longitudinal wave method detection for different detection area lengths, and make the ultrasonic detection system provided by the present invention have better adaptability and practicability. Brief Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 Schematic diagram of an ultrasonic detection system for residual stress in non-metallic materials provided by Embodiment 1 of the present invention;

[0044] Figure 2 Schematic diagram of the calibration component of an ultrasonic detection system for residual stress in non-metallic materials provided by Embodiment 1 of the present invention;

[0045] Figure 3 For Figure 2 Schematic diagram of the measured probe assembly in

[0046] Figure 4 For Figure 3 Node diagram of the measured probe assembly in

[0047] Figure 5 For Figure 4 Cross-sectional view of the structure;

[0048] Figure 6 Schematic diagram of the measurement component of an ultrasonic detection system for residual stress in non-metallic materials provided by Embodiment 1 of the present invention Figure 1 ;

[0049] Figure 7 Schematic diagram of the measurement component of an ultrasonic detection system for residual stress in non-metallic materials provided by Embodiment 1 of the present inventionFigure 2 ;

[0050] Figure 8 For Figure 6 schematic diagram of the actual measurement probe assembly in

[0051] Figure 9 For Figure 8 longitudinal sectional view of the nozzle in

[0052] Figure 10 Flowchart of an ultrasonic detection method for residual stress of non-metallic materials provided in Embodiment II of the present invention;

[0053] Among them, the description of the reference numerals: ultrasonic signal generator and receiver 1, oscilloscope 2, power amplifier 3, preamplifier 4, ultrasonic transmitting probe 5, ultrasonic receiving probe 6, first connecting wire 7, first probe connecting wire 8, second connecting wire 9, second probe connecting wire 10, first signal wire 11, second signal wire 12, computer 13, left slide rail 14, right slide rail 15, specimen block 16, support arm 17, main slide rail 18, strip-shaped through hole 19, chute 20, non-metallic part to be measured 21, calibration probe assembly 100, U-shaped block 101, square box body 102, convex cover body 103, water film 104, first fastening bolt 105, first through hole 106, second through hole 107, A water inlet 108, A water outlet 109, first through hole 110, second through hole 111, third fastening bolt 112, sliding shaft 113, continuous inner through hole 114, actual measurement probe assembly 200, slider 201, internal thread hole 202, nozzle 203, B water outlet 204, B water inlet 205, notch 206, second fastening bolt 207, ear plate 208, rotating shaft 209. Detailed implementation manners

[0054] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0055] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "front", "rear", "upper", "lower", "inner", "outer" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0056] Unless otherwise clearly defined and limited, the terms "connected", "fixed", and "arranged" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be a connection inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0057] In addition, the terms "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of such features, unless otherwise specifically defined.

[0058] In view of the problems existing in the prior art, Embodiment 1 provides an ultrasonic detection system for residual stress of non-metallic materials, as Figures 1 - 9 shown, which includes: an ultrasonic signal generator-receiver 1, an oscilloscope 2, a power amplifier 3, a preamplifier 4, an ultrasonic transmitting probe 5, and an ultrasonic receiving probe 6. The output end of the ultrasonic signal generator-receiver 1 is connected to the input end of the power amplifier 3 through a first connecting wire 7. The output end of the power amplifier 3 is connected to the ultrasonic transmitting probe 5 through a first probe connecting wire 8. The input end of the ultrasonic signal generator-receiver 1 is connected to the output end of the preamplifier 4 through a second connecting wire 9. The input end of the preamplifier 4 is connected to the ultrasonic receiving probe 6 through a second probe connecting wire 10. The synchronization end of the ultrasonic signal generator-receiver 1 is connected to the input end of the oscilloscope 2 through a first signal wire 11. It also includes a calibration component and a measurement component;

[0059] The above-mentioned calibration component includes a left slide rail 14 and a right slide rail 15 placed in parallel, and two groups of calibration probe assemblies 100 are arranged between the left slide rail 14 and the right slide rail 15;

[0060] As Figures 3 - 5 shown, the calibration probe assembly 100 includes a U-shaped block 101. The U-shaped block 101 is perpendicular to the left slide rail 14 and the right slide rail 15. The two sides of the U-shaped block 101 are respectively slidably connected to the left slide rail 14 and the right slide rail 15. Specifically, sliding shafts 113 are arranged on the two sides of the U-shaped block 101. Both the left slide rail 14 and the right slide rail 15 are rectangular strips provided with continuous inner through holes 114 along the side length direction; one end of the sliding shaft 113 is located inside the continuous inner through hole 114, and its diameter matches that of the continuous inner through hole 114;

[0061] Inside the U-shaped groove of the U-shaped block 101, there is a square box body 102 parallel to its inner bottom surface. At the upper end of the square box body 102, there is a convex cover body 103 integrally provided, and at the lower end, there is a water film 104. The inside of the convex cover body 103 is hollow, and a receiving cavity is formed between the convex cover body 103 and the lower end of the square box body 102. The water film 104 is located above the inner bottom surface of the U-shaped block 101. The space between the water film 104 and the inner bottom surface of the U-shaped block 101 is used for the specimen block 16 to penetrate. The specimen block 16 is a non-metallic material specimen to be tested with zero residual stress; A first fastening bolt 105 is penetrated along the central axis direction at the bottom of the U-shaped block 101. The first fastening bolt 105 is threadedly connected to the U-shaped block 101 and is used to closely fit the upper surface of the specimen block 16 with the water film 104. To avoid causing external damage and internal stress to the specimen block 16, the material of the first fastening bolt 105 is preferably plastic;

[0062] On the first side of the convex cover body 103 of a calibration probe assembly 100, there is a first through hole 106, on the second side, there is an A water inlet 108, and on the third side, there is an A water outlet 109. On the fourth side of the convex cover body 103 of another calibration probe assembly 100, there is a second through hole 107, on the second side, there is an A water inlet 108, and on the third side, there is an A water outlet 109; The above-mentioned first side and the fourth side are two opposite faces facing each other. The first through hole 106 is used to install the ultrasonic transmitting probe 5, and the second through hole 107 is used to install the ultrasonic receiving probe 6. Moreover, the complementary angles of the axes of the first through hole 106 and the second through hole 107 with the included angle of the square box body 102 are both the first critical angles of the non-metallic material to be tested; It should be noted that the above-mentioned first side, second side, third side, and fourth side are different sides of the convex cover body 103;

[0063] The above-mentioned actual measurement assembly includes a support arm 17 and a main slide rail 18. The support arm 17 is connected to the main slide rail 18; On the lower side of the main slide rail 18, there are two groups of actual measurement probe assemblies 200;

[0064] As Figures 8 - 9As shown in the figure, the measured probe assembly 200 includes a slider 201. The upper end of the slider 201 is slidably connected to the main slide rail 18. The lower end is provided with a nozzle 203 and is rotatably connected to the first end of the nozzle 203. Specifically, the first end of the nozzle 203 is provided with an ear plate 208, and the ear plate 208 is rotatably connected to the lower end of the slider 201 through a rotating shaft 209, thereby realizing the rotational connection between the nozzle 203 and the slider 201. A strip-shaped through hole 19 is provided on the main slide rail 18 along the sliding direction of the slider 201, and an internal thread hole 202 is provided at the upper end of the slider 201. The first end of the nozzle 203 is provided with a B water outlet 204, the second end is provided with a B water inlet 205, and a notch 206 facing the B water outlet 204. The notches 206 in the two measured probe assemblies 200 are respectively used for installing the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6. A second fastening bolt 207 is penetrated through the strip-shaped through hole 19, and the second fastening bolt 207 is connected to the internal thread hole 202 in a matching manner, and is used to fasten the slider 201 on the main slide rail 18. In a specific embodiment, chutes 20 are provided on both sides of the lower side of the main slide rail 18, internal thread holes 202 are provided on both sides of the upper end of the slider 201, and each side of the upper end of the slider 201 is slidably connected to one of the chutes 20; there are two strip-shaped through holes 19 on the main slide rail 18, and the two strip-shaped through holes 19 are respectively located on both sides of the main slide rail 18 and are respectively directly above the same-side chute 20 and are parallel to the chute 20. A second fastening bolt 207 is penetrated through each strip-shaped through hole 19, and the second fastening bolt 207 is connected to the internal thread hole 202 on the same side in a matching manner. By providing two chutes 20, it can be ensured that when adjusting the probe spacing, the sliding is smoother. Through the cooperation of the two second fastening bolts 207 and the two internal thread holes 202, both the support point and the fixed point of the nozzle 203 on the main slide rail 18 become two, improving the stability of the nozzle 203, which is beneficial to improving the stability and accuracy of the detection data. By providing two chutes 20, the smoothness and smoothness of the nozzle 203 during sliding are improved.

[0065] It should be noted that the power amplifier 3 in this Embodiment 1 is used to amplify the power of the ultrasonic signal emitted by the ultrasonic signal generator-receiver 1 and provide sufficient high excitation energy for the ultrasonic transmitting probe 5. The preamplifier 4 is used to amplify the power of the ultrasonic signal received by the ultrasonic receiving probe 6 and transmit it to the ultrasonic signal generator-receiver 1 for reception. It is easy for those skilled in the art to think that an ultrasonic signal generator-receiver 1 provided with an integrated amplifier circuit can also be directly selected to realize the power amplification function, thereby replacing the configuration of the power amplifier 3 and the preamplifier 4. The non-metallic material to be measured is the same material as the material of the non-metallic part 21 to be measured.

[0066] Compared with the prior art, an ultrasonic detection system for residual stress of non-metallic materials provided in the first embodiment forms a receiving cavity for water coupling agent by setting a square box body 102 and a convex cover body 103 in the calibration component, and makes the incident angles of the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 be the first critical angle of the non-metallic material to be measured through the settings of the first through hole 106 and the second through hole 107; in the above-mentioned actual measurement component, by setting a nozzle 203 which is rotatably connected to a slider 201, the incident angles of the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 installed on the nozzle 203 can be adjusted to be the first critical angle of the non-metallic material to be measured; thus, in the calibration component and the actual measurement component, stable water coupling between the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 and the surface of the specimen block 16 or the non-metallic part 21 to be measured can be achieved, enabling the ultrasonic longitudinal wave to enter the specimen block 16 or the non-metallic part 21 to be measured after propagating in the water coupling agent, and increasing the wave velocity of the ultrasonic longitudinal wave propagating in the specimen block 16 or the non-metallic part 21 to be measured. In this way, according to Snell's law, the ultrasonic longitudinal wave propagates in the specimen block 16 or the non-metallic part 21 to be measured and can excite a critically refracted longitudinal wave (L CR wave), and then the stress coefficient k of the specimen block 16 and the ultrasonic propagation time t0 corresponding to zero stress can be detected through the above-mentioned calibration component, and the ultrasonic propagation time t of the ultrasonic longitudinal wave in the non-metallic part 21 to be measured can be detected through the above-mentioned actual measurement component. Finally, the residual stress value σ corresponding to the ultrasonic propagation time t can be calculated i , realizing the ultrasonic critically refracted longitudinal wave method for detecting the residual stress of non-metallic materials, and solving the problem that the critically refracted longitudinal wave cannot be excited in non-metallic materials by using a conventional acoustic wedge block, resulting in the inability to perform the ultrasonic critically refracted longitudinal wave method for detecting the residual stress of non-metallic materials

[0067] The calibration probe assembly 100 in the calibration component is slidably connected to the left slide rail 14 and the right slide rail 15 through a U-shaped block 101, and the actual measurement probe assembly 200 in the actual measurement component is slidably connected to the main slide rail 18 through a slider 201. Thus, the distance between the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 can be adjusted according to the residual stress distribution of the non-metallic part 21 to be measured and the requirement of the detection area length, which can adapt to the non-metallic part 21 with various residual stress distributions, meet the requirements of various detection area lengths, and realize the ultrasonic critically refracted longitudinal wave method for different detection area lengths, making the ultrasonic detection system provided by the present invention have better adaptability and practicability

[0068] Since the ultrasonic propagation speed will change due to the interference of environmental factors such as temperature and humidity, for example, although patent CN201820053331.5 solves the problem that it is difficult to ensure the consistency of the coupling layer thickness between the organic glass wedge and the workpiece to be measured in the existing ultrasonic residual stress testing device, it uses a one-transmitter and one-receiver inclined incidence probe, and does not consider the influence of controlled variables, external air, temperature, humidity, etc. on the ultrasonic propagation speed, which will cause errors in the measurement data and make them inaccurate. Therefore, the detection results of most existing detection systems using a one-transmitter and one-receiver detection system usually need to be compensated by a temperature-sound speed curve.

[0069] Therefore, in a further embodiment, a third set of calibration probe assemblies 100 is also provided between the left slide rail 14 and the right slide rail 15. The third set of calibration probe assemblies 100 is located between the above two sets of calibration probe assemblies 100. A second through hole 107 is provided on the fourth side of the convex cover body 103 in the third set of calibration probe assemblies 100, an A water inlet 108 is provided on the second side, and an A water outlet 109 is provided on the third side.

[0070] A third set of actual measurement probe assemblies 200 is also provided on the lower side of the main slide rail 18. The third set of actual measurement probe assemblies 200 is located between the above two sets of actual measurement probe assemblies 200. An ultrasonic receiving probe 6 is installed in the notch 206 of the third set of actual measurement probe assemblies 200.

[0071] By providing the third set of calibration probe assemblies 100 and the third set of actual measurement probe assemblies 200, a one-transmitter and two-receiver ultrasonic detection system can be formed in the calibration assembly and the actual measurement assembly, that is, there is one ultrasonic transmitter probe 5 and two ultrasonic receiving probes 6 in the detection system. During detection, the two ultrasonic receiving probes 6 are placed at a certain distance apart. Then, the two ultrasonic receiving probes 6 will obtain two different ultrasonic propagation times. By calculating the time difference between the two ultrasonic propagation times, that is, the propagation time of the ultrasonic wave between the two ultrasonic receiving probes 6, the acoustic time difference is calculated using this time difference, and the residual stress of the non-metallic part 21 to be measured is calculated through this acoustic time difference. Since the two ultrasonic propagation times are affected by environmental factors such as temperature, the influence of environmental factors is offset by calculating the acoustic time difference using the time difference. Therefore, temperature compensation is no longer required, automatic compensation of environmental factors is achieved, interference from environmental factors such as external air, temperature, and humidity is removed, and the accuracy of the detection results is improved.

[0072] Since the first critical angles of different materials are different, during the ultrasonic detection of the residual stress of different non-metallic materials, the incident angles of the ultrasonic transmitter probe 5 and the ultrasonic receiving probe 6 will change with the type of material. To adapt to the detection of a variety of non-metallic materials and improve the applicability of the calibration assembly, in one embodiment, the U-shaped block 101 is detachably connected to the square box body 102. Specifically, such as Figure 3As shown, the U-shaped block 101 is provided with a first through hole 110, and the square box body 102 is provided with a second through hole 111. The first through hole 110 and the second through hole 111 are coaxial. A third fastening bolt 112 is arranged in the first through hole 110 and the second through hole 111. By means of the third fastening bolt 112, the calibration assembly can replace the square box body 102 according to the detection requirements of different materials, so as to ensure that the incident angles of the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 installed on the convex cover body 103 are always the first critical angle of the measured material.

[0073] Furthermore, the convex cover body 103 is a hollow trapezoidal platform. The axis of the A water inlet 108 is perpendicular to the second side surface, and the axis of the A water outlet 109 is perpendicular to the third side surface; the axis of the first through hole 106 is perpendicular to the first side surface, and the axis of the second through hole 107 is perpendicular to the fourth side surface, and the acute angles between the first side surface and the fourth side surface and the square box body 102 are both the first critical angle of the non-metallic material to be measured. Thus, by directly installing the ultrasonic transmitting probe 5 into the first through hole 106 and installing the ultrasonic receiving probe 6 into the second through hole 107, it can be ensured that the incident angles of the two probes are the first critical angle of the non-metallic material to be measured. The installation is convenient and the angle control is fast, and it also reduces the manufacturing difficulty of the convex cover body 103 caused by the need to ensure the angles between the axes of the first through hole 106 and the second through hole 107 and the square box body 102, which is beneficial to mass production.

[0074] In a more specific embodiment, the support arm 17 is a robotic arm. Through the robotic arm, the angle adjustment and large-range movement of the main slide rail 18 can be realized. Furthermore, the large-range movement of the actual measurement probe assembly 200 and the wider and more flexible angle adjustment of the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 can be realized, enabling the detection of non-metallic parts with a large area range and complex curved surfaces. For example, the detection of aviation transparent parts. Aviation transparent parts are an important part of an aircraft. Their main function is to form a sealed cockpit with the fuselage cockpit section, protecting the pilot from the impact of oncoming high-speed airflow and external environmental threats, providing a comfortable, airtight, spacious, bright activity space and survival environment for the pilot under flight conditions, a clear, wide and distortion-free field of vision, and matching with the head-up display to complete takeoff, landing, combat and transportation tasks. The strength and service life of aviation transparent parts determine the quality and service time of the aircraft. If their residual stress is too large, it will be difficult for them to withstand high altitude and high pressure and crack, resulting in disasters. The measurement of the residual stress of aviation transparent parts has extremely important guiding significance for improving their strength and predicting their service life in production.

[0075] In a specific embodiment, the nozzle 203 is a Y-shaped nozzle. There are two B water inlets 205 at the second end of the nozzle 203. The notch 206 is centered between the two B water inlets 205. The two B water inlets 205 are symmetrically located on both sides above the B water outlet 204 at the first end of the nozzle 203. For the nozzle 203 with such a symmetric structure, through the two symmetrically arranged B water inlets 205, it can ensure that the nozzle 203 is filled with water coupling agent. It not only has the advantages of convenient and fast use, large detection range, and avoiding long-term immersion of workpieces, but also can improve the jet stability of the coupling water column, thereby improving the stability of ultrasonic coupling.

[0076] Patent CN201810954496.4 solves the problems of the change in acoustoelastic constant caused by different thermal effects in the measurement area and the error introduced by the existence of the zero-stress propagation time. However, the area division method using an infrared thermal imager in it can only detect the stress magnitude of a single device or a single depth. When the L CR When the L wave propagates in a component with a finite thickness, its penetration depth is a function of its frequency. Experimental studies have shown that the relationship between the depth and the frequency satisfies the following empirical formula:

[0077] D = Vxf -0.96

[0078] In the formula, D is the penetration depth, in mm; f is the transceiver frequency of the ultrasonic probe, in MHz; V is the sound velocity in the component, in km / s.

[0079] On the basis of realizing the ultrasonic critical refraction longitudinal wave method for detecting the residual stress of non-metallic materials in this embodiment, more specifically, both the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 are multi-chip combined probes, and each chip corresponds to a different frequency. Thus, the residual stress of different depth regions of the non-metallic part 21 to be measured can be detected by using different probe frequencies.

[0080] The ultrasonic detection system in this embodiment further includes a computer 13. The computer 13 is connected to the output end of the oscilloscope 2 through a second signal line 12. The oscilloscope 2 converts the graphic signal into a digital signal and transmits it to the computer 13 for data analysis and residual stress calculation. The computer 13 is built-in with a signal analysis module. The signal analysis module stores various parameters including the acoustoelastic coefficient and zero-stress acoustic time of typical non-metallic materials, the propagation time of the critical refraction longitudinal wave in the zero-stress samples of various types of non-metallic materials, the variation law of the critical refraction longitudinal wave with different frequencies under stress, etc. It can set the propagation direction, sound velocity, penetration depth, etc. of the critical refraction longitudinal wave. Thus, the residual stress of the non-metallic part 21 to be measured can be directly calculated through the computer 13, improving the detection efficiency and automation degree.

[0081] To better illustrate the usage method and detection steps of an ultrasonic detection system for residual stress of non-metallic materials provided in the first embodiment, based on the ultrasonic detection system of the first embodiment, the present invention also provides a second embodiment, an ultrasonic detection method for residual stress of non-metallic materials, as follows Figure 10 shown, including the following steps:

[0082] S1. According to the determined detection area of the non-metallic part 21 to be measured, determine the detection frequency f of the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 i and detection parameters such as the spacing, the filtering bandwidth of the oscilloscope 2, and the ultrasonic excitation voltage of the ultrasonic signal generator-receiver 1. Set the ultrasonic signal generator-receiver 1 and the oscilloscope 2 according to each detection parameter, adjust the spacing of the calibration probe assembly 100 and the spacing of the actual measurement probe assembly 200, and make the spacing of the calibration probe assembly 100 and the spacing of the actual measurement probe assembly 200 the same;

[0083] S2. Install the ultrasonic transmitting probe 5 into the first through hole 106, and install the ultrasonic receiving probe 6 into the second through hole 107; place the specimen block 16 on the calibration probe assembly 100, rotate the first fastening bolt 105 to fix the specimen block 16, inject a stable water flow into each A water inlet 108 to fill each accommodation cavity with water, so that the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 are stably coupled to the calibration area of the specimen block 16; fix both ends of the specimen block 16 on the clamping device of the tensile machine;

[0084] Start the ultrasonic signal generator-receiver 1. According to the waveform information of the oscilloscope 2, obtain the time moment of the longitudinal wave peak value emitted by the ultrasonic signal generator-receiver 1 and the time moment of receiving the longitudinal wave peak value, and calculate the time difference between the time moment of emitting the longitudinal wave peak value and the time moment of receiving the longitudinal wave peak value, which is the ultrasonic critically refracted longitudinal wave propagation time t0 of the specimen block 16;

[0085] S3. Within the elastic limit range of the material of the non-metallic part 21 to be measured, that is, the tensile stress values are all less than the elastic limit of the non-metallic part 21 to be measured, conduct a tensile test on the specimen block 16. The tensile test includes at least ten increasing tensile stress values σ n , and obtain the corresponding ultrasonic critically refracted longitudinal wave propagation time t of the specimen block 16 under each tensile stress value n ; it should be noted that according to the provisions of the national standard GB / T32073-2015, each tensile stress value needs to be stretched no less than 5 times, and the corresponding ultrasonic critically refracted longitudinal wave propagation time t of the specimen block 16 under this tensile stress value is obtained by taking the average value n .

[0086] Calculate the time difference Δt of the ultrasonic critically refracted longitudinal wave corresponding to the specimen block 16 under different tensile stress values, record the change in tensile stress Δσ output by the above tensile machine, plot the coordinate graph of the tensile stress value and the time difference, perform linear fitting on the data, and obtain the reciprocal k of the straight line slope. k is the stress coefficient of the non-metallic material to be measured;

[0087] S4. Install the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 into the respective notches 206, place the non-metallic part 21 to be measured below the above-mentioned actual measurement assembly and make its detection area located between the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6. Rotate the second fastening bolt 207 to fasten the slider 201 on the main slide rail 18, and rotate each nozzle 203 to adjust the incident angle of the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 to the first critical angle of the non-metallic material to be measured; Inject a stable water flow into each B water inlet 205 to fill the nozzle 203 with water;

[0088] S5. According to the waveform information of the oscilloscope 2, obtain the propagation time t of the ultrasonic critically refracted longitudinal wave of the non-metallic part 21 to be measured. According to the propagation time t0 of the ultrasonic critically refracted longitudinal wave of the specimen block 16 and the stress coefficient k of the non-metallic material to be measured, calculate the residual stress σ of the detection area of the non-metallic part 21 to be measured i :

[0089] σ i - σ0 = k(t - t0);

[0090] In the formula, σ0 is the residual stress of the specimen block 16, with the unit of MPa; t0 is the propagation time of the ultrasonic critically refracted longitudinal wave of the specimen block 16, with the unit of ns; t is the propagation time of the ultrasonic critically refracted longitudinal wave of the non-metallic part 21 to be measured, with the unit of ns; t - t0 = Δt, which is the change in propagation time (also called the time difference), with the unit of ns; k is the stress coefficient of the non-metallic material to be measured.

[0091] Furthermore, it also includes the steps:

[0092] S6. Change the frequencies of the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6 to f j , According to the waveform information of the oscilloscope 2, obtain the propagation time t of the ultrasonic critically refracted longitudinal wave of the non-metallic part 21 to be measured j , According to the propagation time t0 of the ultrasonic critically refracted longitudinal wave of the specimen block 16 and the stress coefficient k of the non-metallic material to be measured, calculate the residual stress σ of the detection area of the non-metallic part 21 to be measured j :

[0093] σ j - σ0 = k(t j - t0);

[0094] In the formula, σ0 is the residual stress of the specimen block 16, with the unit of MPa; t0 is the propagation time of the ultrasonic critically refracted longitudinal wave of the specimen block 16, with the unit of ns; t j is the propagation time of the ultrasonic critically refracted longitudinal wave of the non-metallic part 21 to be measured, with the unit of ns; t j - t0 = Δt, which is the change in propagation time (also called the time difference), with the unit of ns; k is the stress coefficient of the non-metallic material to be measured.

[0095] S7. According to the residual stress σ i and σ j , calculate the residual stress depth gradient σ i-j of the non-metallic part 21 to be measured. The specific calculation formula is:

[0096]

[0097] In the formula, σ i-j is the residual stress within the depth range of the non-metallic part D i-j to be measured, with the unit of MPa; f i and f j are the detection frequencies of the ultrasonic transmitting probe 5 and the ultrasonic receiving probe 6, with the unit of MHz. The residual stresses of the non-metallic part 21 detected correspondingly are σ i and σ j .

[0098] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultrasonic detection system for residual stress of non-metallic materials, characterized in that: It includes an ultrasonic signal generator / receiver with power amplification function, an oscilloscope, an ultrasonic transmitting probe and an ultrasonic receiving probe. The output end of the ultrasonic signal generator / receiver is connected to the ultrasonic transmitting probe through a first probe connecting wire, the input end of the ultrasonic signal generator / receiver is connected to the ultrasonic receiving probe through a second probe connecting wire, the synchronization end of the ultrasonic signal generator / receiver is connected to the input end of the oscilloscope through a first signal wire, and it also includes a calibration component and a measurement component; The calibration component includes a left slide rail and a right slide rail placed in parallel, and two groups of calibration probe components are arranged between the left slide rail and the right slide rail; The calibration probe component includes a U-shaped block, the U-shaped block is perpendicular to the left slide rail and the right slide rail, and both sides of the U-shaped block are slidably connected to the left slide rail and the right slide rail respectively; A square box body parallel to its inner bottom surface is arranged in the U-shaped groove of the U-shaped block. A convex cover body is integrally arranged at the upper end of the square box body, and a water film is arranged at the lower end. The inside of the convex cover body is hollow, and a containing cavity is formed between the convex cover body and the lower end of the square box body. The water film is located above the inner bottom surface of the U-shaped block, and the space between the water film and the inner bottom surface of the U-shaped block is for the specimen block to penetrate through. The specimen block is a non-metallic material specimen to be tested with zero residual stress; A first fastening bolt is arranged through the bottom of the U-shaped block along the central axis direction, and the first fastening bolt is threadedly connected to the U-shaped block for tightly fitting the upper surface of the specimen block with the water film; A first through hole is arranged on the first side surface of the convex cover body of one calibration probe component, an A water inlet is arranged on the second side surface, and an A water outlet is arranged on the third side surface. A second through hole is arranged on the fourth side surface of the convex cover body of the other calibration probe component, an A water inlet is arranged on the second side surface, and an A water outlet is arranged on the third side surface; The first side surface and the fourth side surface are two opposite and facing surfaces. The first through hole is used to install the ultrasonic transmitting probe, the second through hole is used to install the ultrasonic receiving probe, and the complementary angles of the axes of the first through hole and the second through hole with the square box body are both the first critical angle of the non-metallic material to be tested; The measurement component includes a support arm and a main slide rail, and the support arm is connected to the main slide rail; Two groups of measurement probe components are arranged on the lower side of the main slide rail; The measurement probe component includes a slider, the upper end of the slider is slidably connected to the main slide rail, and the lower end is provided with a nozzle and is rotatably connected to the first end of the nozzle; A strip-shaped through hole is arranged on the main slide rail along the sliding direction of the slider, and an internal thread hole is arranged at the upper end of the slider; The first end of the nozzle is provided with a B water outlet, the second end is provided with a B water inlet and a notch facing the B water outlet. The notches in the two groups of measurement probe components are respectively used to install the ultrasonic transmitting probe and the ultrasonic receiving probe; A second fastening bolt is arranged through the strip-shaped through hole, and the second fastening bolt is in matching connection with the internal thread hole for fastening the slider on the main slide rail.

2. The ultrasonic detection system for residual stress of a non-metallic material according to claim 1, characterized in that: A third set of the calibration probe assemblies is further disposed between the left slide rail and the right slide rail. The third set of calibration probe assemblies is located between the two sets of calibration probe assemblies. A second through hole is disposed on a fourth side surface of the convex cover body in the third set of calibration probe assemblies, an A water inlet is disposed on a second side surface, and an A water outlet is disposed on a third side surface. A third set of the measured probe assemblies is further disposed below the main slide rail. The third set of measured probe assemblies is located between the two sets of measured probe assemblies. An ultrasonic receiving probe is installed in the notch in the third set of measured probe assemblies.

3. The ultrasonic detection system for residual stress of a non-metallic material according to claim 1, wherein: The convex cover body is a hollow trapezoidal platform. The axis of the A water inlet is perpendicular to the second side surface, and the axis of the A water outlet is perpendicular to the third side surface. The axis of the first through hole is perpendicular to the first side surface, and the axis of the second through hole is perpendicular to the fourth side surface. The acute angles between the first side surface and the fourth side surface and the square box body are both the first critical angles of the non-metallic material to be measured.

4. The ultrasonic detection system for residual stress of a non-metallic material according to claim 1, characterized in that: The nozzle is a Y-shaped nozzle. There are two B water inlets at the second end of the nozzle. The notch is centered between the two B water inlets. The two B water inlets are symmetrically located on both sides above the B water outlet at the first end of the nozzle.

5. An ultrasonic detection system for residual stress of a non-metallic material according to claim 1, characterized in that: Sliding shafts are disposed on both sides of the U-shaped block. The left slide rail and the right slide rail are both rectangular strips provided with continuous inner through holes along the side length direction. One end of the sliding shaft is located in the continuous inner through hole, and its diameter matches the continuous inner through hole.

6. The ultrasonic detection system for residual stress of a non-metallic material according to claim 1, characterized in that: Both the ultrasonic transmitting probe and the ultrasonic receiving probe are multi-chip combined probes, and each chip corresponds to a different frequency.

7. An ultrasonic detection system for residual stress of a non-metallic material according to claim 1, characterized in that: The ultrasonic detection system further includes a computer, and the computer is connected to the output end of the oscilloscope through a second signal line.

8. An ultrasonic detection method for residual stress of non-metallic materials, characterized in that, Using the ultrasonic detection system for residual stress of non-metallic materials according to any one of claims 1 to 7, the steps are as follows: S1. Determine the detection frequencies of the ultrasonic emission probe and the ultrasonic reception probe, according to the determined detection area of the non-metallic part to be measured. And the spacing, the filtering bandwidth of the oscilloscope, and the ultrasonic excitation voltage detection parameter of the ultrasonic signal generator and receiver. Set the ultrasonic signal generator and receiver according to each detection parameter, adjust the spacing of the calibration probe assembly and the spacing of the actual measurement probe assembly, and make the spacing of the calibration probe assembly the same as that of the actual measurement probe assembly. S2, install the ultrasonic transmitting probe into the first through hole, and install the ultrasonic receiving probe into the second through hole; place the specimen block on the calibration probe assembly, rotate the first fastening bolt to fix the specimen block, inject stable water flow into each A water inlet to fill the accommodation cavity with water, and stably couple the ultrasonic transmitting probe and the ultrasonic receiving probe to the calibration area of the specimen block; fix both ends of the specimen block on the clamping device of the tensile machine. Start the ultrasonic signal generating and receiving instrument, and obtain the ultrasonic critically refracted longitudinal wave propagation time t0 of the specimen block according to the waveform information of the oscilloscope. S3. Within the elastic limit of the material of the non-metal part to be measured, perform a tensile test on the specimen block, and the tensile test includes at least ten increasing tensile stress values σ n , and obtain the propagation time t of the ultrasonic critically refracted longitudinal wave of the specimen block under each tensile stress value n ; Calculate the acoustic time difference Δt of the critically refracted longitudinal wave of the specimen block under different tensile stress values and the change Δσ of the tensile stress output by the tensile machine, plot the coordinate graph of the tensile stress value and the acoustic time difference, perform linear fitting on the data, and obtain the reciprocal of the slope of the straight line , which is the stress coefficient of the non-metallic material to be measured; S4, install the ultrasonic transmitting probe and the ultrasonic receiving probe into each notch respectively, place the non-metallic part to be measured below the measured assembly and make its detection area located between the ultrasonic transmitting probe and the ultrasonic receiving probe, rotate the second fastening bolt to fasten the slider on the main slide rail, and rotate each nozzle to adjust the incident angles of the ultrasonic transmitting probe and the ultrasonic receiving probe to the first critical angle of the non-metallic material to be measured; inject stable water flow into each B water inlet to fill the nozzle with water. S5. Obtain the ultrasonic critically refracted longitudinal wave propagation time t of the non-metallic part to be measured according to the waveform information of the oscilloscope, and calculate the residual stress σ of the detection area of the non-metallic part to be measured according to the ultrasonic critically refracted longitudinal wave propagation time t0 of the specimen block and the stress coefficient of the non-metallic material to be measured . i .

9. The ultrasonic detection method for residual stress of a non-metallic material according to claim 8, characterized in that, It also includes the steps: S6. Change the frequencies of the ultrasonic transmitting probe and the ultrasonic receiving probe to . According to the waveform information of the oscilloscope, obtain the ultrasonic critically refracted longitudinal wave propagation time t of the non-metallic part to be measured j . According to the ultrasonic critically refracted longitudinal wave propagation time t0 of the specimen block and the stress coefficient of the non-metallic material to be measured . Calculate the residual stress σ of the detection area of the non-metallic part to be measured j ; S7. Calculate the residual stress depth gradient σ i and σ j of the non-metallic part to be measured according to the residual stresses σ i-j .

10. The ultrasonic detection method for residual stress of a non-metallic material according to claim 8, wherein The residual stress σ of the non-metallic part detection area to be measured i The calculation formula is as follows: ； Wherein, σ0 is the residual stress of the sample block, with the unit of MPa; t0 is the propagation time of the ultrasonic critically refracted longitudinal wave of the sample block, with the unit of ns; t is the propagation time of the ultrasonic critically refracted longitudinal wave of the non-metallic part to be measured, with the unit of ns; t - t0 = ∆t, which is the change in the propagation time, with the unit of ns; is the stress coefficient of the non-metallic material to be measured.

11. The ultrasonic detection method for residual stress of a non-metallic material according to claim 9, characterized in that, The residual stress depth gradient σ of the non-metallic part to be measured i-j has the following calculation formula: ; Where, σ i-j is the residual stress within the depth range of the non-metallic part D to be measured, with the unit of MPa; i-j and are the detection frequencies of the ultrasonic emission probe and the ultrasonic reception probe, with the unit of MHz, and the residual stresses of the non-metallic part D to be measured detected correspondingly are σ i and σ j respectively. .

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