Methods, devices, and electronic equipment for detecting defects in the thrust chamber of rocket engines.

Abstract

This application relates to the field of welding technology, and in particular to a method, apparatus, and electronic equipment for detecting weld defects in rocket engine thrust chambers. The weld defect detection method includes: an analysis and screening step: using multiple guided wave modes obtained by excitation along different directions captured by the receiving module in a known component with weld defects, and calibrating the guided wave modes that can determine the location of the weld defects in the known component and meet the screening criteria as target guided wave modes; and a detection step: using the target guided wave mode to detect the component under test, so as to detect and determine the location of the defects in the component under test. The ultrasonic guided wave detection method used in this application for detecting weld detachment defects between the inner and outer walls of the combustion chamber milled groove along the end face has the advantages of high detection efficiency and low requirements for probe accessibility in the monitoring area and the flatness of the outer wall weld surface.

Description

Technical Field

[0001] This application relates to the field of welding technology, and in particular to a method, apparatus and electronic equipment for detecting defects in the weld seam of a rocket engine thrust chamber. Background Technology

[0002] Currently, with the continuous advancement of aerospace technology, spacecraft engine technology has developed rapidly. Liquid rocket engines are widely used in launch vehicles and spacecraft. Compared with solid rocket engines, liquid rocket engines have advantages such as longer operating time, higher specific impulse, easier thrust vector control, and re-startability. A liquid rocket engine mainly consists of a thrust chamber, propellant supply system, control system, and engine assembly components. The thrust chamber is the component that converts the chemical energy of the liquid propellant into jet kinetic energy and generates thrust. The engine thrust chamber structure mainly consists of the head, body (combustion chamber, nozzle), nozzle extension section, and assembly support. The thrust chamber body is an essential component of the engine thrust chamber; its structure is a Laval surface type, typically composed of a cylindrical section, a contraction section, and an expansion section. The combustion chamber in the thrust chamber body is mainly responsible for mixing and burning the fuel to generate high-temperature, high-pressure gas. The gas is accelerated and discharged through the contraction section to obtain retro-thrust.

[0003] To withstand the high temperatures of the combustion gases, combustion chambers typically employ regenerative cooling technology. This involves milling grooves on the outer surface of the inner wall to create cooling channels, then assembling the inner and outer walls together. Each reinforced area and the outer wall is then brazed to form welds, connecting the inner and outer walls. To isolate the cooling channels from each other, the milled inner and outer walls must have excellent mechanical bonding at the weld joints, forming hundreds of closed tubular channels. Because the coolant pressure flowing within the cooling channels is much higher than the combustion gas pressure inside the combustion chamber, weld detachment and crack initiation are prone to occur at the weld joints between the inner and outer walls. Both defects reduce the connection strength between the inner and outer walls, causing liquid cross-flow, leading to localized structural instability and tearing of the combustion chamber, and in severe cases, even engine cooling failure, nozzle burnout, and flight mission failure.

[0004] Currently, there are three common non-destructive testing (NDT) methods for detecting weld detachment defects on the inner and outer walls of milled grooves. The first NDT method uses ultrasonic testing to detect internal weld detachment defects. The principle of this method is that when ultrasound propagates within an object, the internal structure reflects, scatters, and refracts the incident sound waves. By extracting and analyzing the reflected and transmitted signals, the internal structure and defects of the object can be determined. In actual testing, this method typically involves placing an ultrasonic probe on the outer wall of the combustion chamber for point-by-point testing, generating and receiving ultrasonic signals in a self-generating and self-receiving manner. When weld detachment exists at the interface, the ultrasonic bulk wave passing through the detached area will generate reflected echo signals caused by the weld detachment defect, which are received by the ultrasonic probe, thus determining the location of the weld detachment defect. The second NDT method uses X-ray imaging to inspect the side walls of the thrust chamber. The principle of this method is that when X-rays are incident on the workpiece, if there are defects inside the workpiece, the difference in material density between the defects and the workpiece itself causes a change in the intensity of the transmitted rays. By recording the changes in the intensity of the transmitted rays using film or a detector, the internal defects of the workpiece can be detected. In actual testing, this method involves attaching a film to the outer wall of the combustion chamber and using an X-ray flaw detector to irradiate the center of the thrust chamber. The resulting washed film is then used to determine the welding condition of each interface. The third testing method is laser holographic detection. This method works by applying a load to an object, causing surface deformation. Areas with internal defects exhibit different surface deformations compared to surrounding areas. Using holographic interferometry, these different surface deformations are converted into interference fringes representing light intensity and recorded using a photosensitive medium. Defective areas will produce distorted interference fringes, allowing for the evaluation of the brazing condition within the product.

[0005] However, the aforementioned non-destructive testing methods for weld detachment defects between inner and outer walls still have certain shortcomings. Specifically, traditional ultrasonic testing methods using the pulse-echo method typically place the ultrasonic probe on the side wall of the combustion chamber and use body waves to inspect the weld point by point. Due to the curvature of the outer wall of the combustion chamber, and the formation of localized protrusions caused by welding on the outer wall of the welding area, it is difficult to accurately position and orient the probe on the outer wall, making it difficult to determine weld quality using this method. Furthermore, this method requires point-by-point inspection on the outer wall, resulting in low efficiency. When using X-rays, the numerous milled grooves on the inner wall of the combustion chamber, coupled with the complex Laval surface structure (contracting then expanding along the axial direction), cause significant scattering of X-rays as they propagate through the structure. This makes it difficult to accurately image finer structures such as welds on film, hindering weld quality assessment. Moreover, this method is costly and inefficient. Laser holographic inspection requires a dedicated testing laboratory with vibration reduction and light shielding, placing high demands on the testing environment and loading methods, as the influencing factors are complex. Laser holographic inspection necessitates loading the structure, and the structural deformation caused by this load may not meet the required dimensional accuracy. Furthermore, residual stress may remain within the structure after inspection, reducing its mechanical properties such as stiffness and stability.

[0006] Therefore, there is an urgent need for a method, device, and electronic equipment for detecting defects in the weld seams of rocket engine thrust chambers, in order to solve the technical problems in the existing technology to a certain extent. Summary of the Invention

[0007] The purpose of this application is to provide a method, device, and electronic equipment for detecting defects in the weld seam of a rocket engine thrust chamber, so as to solve the technical problems existing in the prior art to a certain extent.

[0008] This application provides a method for detecting weld defects in a liquid rocket engine. The method is applicable to a weld defect detection device, which includes an excitation component. The excitation component includes a transmitting module and a receiving module connected in communication. The method includes: using the excitation component on a known component with weld defects; exciting an ultrasonic signal at the normal location of the weld on the known component via the transmitting module; and capturing multiple guided wave mode groups using the receiving module.

[0009] The method for detecting weld defects includes the following steps after the activation step:

[0010] Analysis and screening steps: The various guided wave modes captured by the receiving module and excited in different directions are used in a known part with weld defects. The guided wave modes that can determine the location of the weld defects in the known part and meet the screening criteria are identified as target guided wave modes.

[0011] Detection steps: Use the target guided wave mode to detect the test piece, so as to detect and determine the location of the defect in the test piece.

[0012] In the above technical solution, the excitation step further includes the following steps:

[0013] Steps for calculating the number of excitation components: Calculate the arc length of adjacent excitation components along the circumferential direction according to formula (1);

[0014]

[0015] Where l represents the arc length of adjacent excitation components along the circumferential direction; λ is the wavelength of the excitation ultrasonic signal; d represents the diameter of the combustion chamber; n is the number of structural units on the end face of the combustion chamber; and h is the wall thickness of the combustion chamber.

[0016] The number of excitation components is calculated according to formula (2):

[0017]

[0018] Wherein, N represents the number of the excitation components, and L is the perimeter of the known component along its axial cross section;

[0019] Excitation position arrangement steps: Arrange N excitation components at a spacing of l on the axial section of the known component;

[0020] Setting the excitation direction step: Excite ultrasonic signals along the circumferential, radial, and axial directions of the known component through N of the N excitation components, respectively;

[0021] Guided wave mode group acquisition steps: For guided waves propagating along the axial direction of the known component, the receiving module can capture the L(a,b) type longitudinal wave mode group generated by axial excitation, the T(c,d) type torsional wave mode group generated by circumferential excitation, and the F(e,f) type bending wave mode group generated by radial excitation, according to the particle vibration direction, where a, b, c, d, e, and f are all integers, a and c are both greater than or equal to 0, and b, d, f, and e are all greater than or equal to 1.

[0022] In the above technical solution, the analysis step further includes the following steps:

[0023] Based on the excitability criterion, guided waves of the T(0,1) mode generated by circumferential excitation, guided waves of the F(1,1) mode generated by radial excitation, and guided waves of the L(0,1) and F(1,1) modes generated by axial excitation are identified as excitable guided waves.

[0024] In the above technical solution, the analysis and screening step further includes the following steps:

[0025] The guided wave of the T(0,1) mode generated by circumferential excitation, the guided wave of the F(1,1) mode generated by radial excitation, and the guided wave of the L(0,1) and F(1,1) modes generated by axial excitation are subjected to mode screening.

[0026] The screening criteria specifically include the following steps:

[0027] The excitability criterion is adopted: excitability refers to whether an ultrasonic guided wave can be excited and generated and propagate stably in the structure.

[0028] The mode purity criterion is adopted: mode purity refers to the number of waveguide modes that can be excited simultaneously in the structure; the fewer the number of waveguide modes that can be excited simultaneously, the higher the mode purity.

[0029] The sensitivity criterion for solder detachment defects is adopted: the sensitivity to solder detachment defects is to determine whether the wave will interact with the solder detachment defect when it passes through the defect and cause a large amplitude reflected echo signal.

[0030] The energy flux density distribution criterion in the wave propagation direction is adopted: the energy flux density distribution in the wave propagation direction refers to the energy transferred per unit time through a unit area perpendicular to the wave propagation direction;

[0031] The above criteria can be used to identify the F(1,1)-like guided wave generated by radial excitation as the target guided wave mode.

[0032] In the above technical solution, the detection step further includes the following steps:

[0033] Application steps: Apply the target waveguide mode of type F(1,1) to the device under test;

[0034] Determination steps: During guided wave propagation, when a reflected signal caused by a defect is detected, the distance between the defect location and the receiving module or the transmitting module can be determined according to formula (3):

[0035]

[0036] Wherein, Δt represents the time difference between the receiving module receiving the excitation signal and the receiving module receiving the reflected signal caused by the defect, and X represents the distance between the defect location and the receiving module or the transmitting module;

[0037] To quantitatively measure the signal arrival time, both the excitation signal and the received reflected signal caused by the defect are subjected to Hilbert transform to obtain the signal envelope, thereby determining the signal peak time.

[0038] This application also provides a detection device for weld defects in the thrust chamber of a rocket engine, which is applied to a weld defect detection method. The weld defect detection device includes a clamping assembly and an excitation assembly.

[0039] The clamping assembly has a clamping portion that can be sleeved on the test piece and a plurality of limiting portions that are spaced apart along the circumference of the test piece in the clamping portion; at least a portion of the excitation assembly is disposed in the limiting portion;

[0040] The diameter of the clamping part is adjustable so that the clamping part can be fitted onto the test piece of different diameters.

[0041] In the above technical solution, the excitation component further includes a radially polarized piezoelectric transducer;

[0042] The radially polarized piezoelectric transducer includes a transmitting module and a receiving module with communication connections.

[0043] In the above technical solution, the clamping assembly further includes a tracked clamp with an adjustable diameter.

[0044] This application also provides an electronic device, including: a processor and a memory;

[0045] The processor executes the steps of the above method by calling the program or instructions stored in the memory.

[0046] This application also provides a computer-readable storage medium that stores programs or instructions;

[0047] The program or instructions enable the computer to perform the steps of the above methods.

[0048] Compared with the prior art, the beneficial effects of this application are as follows:

[0049] This application provides a method for detecting weld defects in a liquid rocket engine. The method is applicable to a weld defect detection device, which includes an excitation component comprising a transmitting module and a receiving module connected in communication. The weld defect detection method includes: an excitation step: using the excitation component on a known component with weld defects, exciting an ultrasonic signal at the normal location of the weld on the known component via the transmitting module, and capturing multiple guided wave modes using the receiving module; the method further includes the following steps after the excitation step:

[0050] Analysis and screening steps: The various guided wave modes captured by the receiving module and excited in different directions are used in a known part with weld defects. The guided wave modes that can determine the location of the weld defects in the known part and meet the screening criteria are identified as target guided wave modes.

[0051] Detection steps: Use the target guided wave mode to detect the test piece, so as to detect and determine the location of the defect in the test piece.

[0052] Specifically, this application is applied to combustion chambers. The method used in this application to detect weld defects in the weld between the inner and outer walls of the combustion chamber milled groove using incident ultrasonic guided waves along the end face has advantages over the commonly used ultrasonic bulk wave detection method that places ultrasonic probes on the side walls. These advantages include higher detection efficiency, lower requirements for probe accessibility in the monitoring area, and lower requirements for the flatness of the outer wall weld surface. Furthermore, due to the curvature of the outer wall of the combustion chamber, and the formation of local protrusions caused by welding on the outer wall of the welded area, it is difficult to accurately position and orient the probe on the outer wall, making it difficult to judge weld quality using probes placed on the side walls. In addition, this detection method requires point-by-point detection along the outer wall, resulting in very low detection efficiency. Compared to the detection method proposed in this paper, traditional X-ray detection, due to its complex structure and strong scattered signal, is not conducive to imaging fine structures such as welds, thus making it difficult to judge weld quality. Furthermore, compared to laser holographic detection, the ultrasonic detection method proposed in this paper has lower detection cost, higher detection efficiency, does not cause structural deformation, and is simpler and more sensitive for time-domain signal detection at the combustion chamber end face.

[0053] This application also provides a device for detecting weld defects in the thrust chamber of a rocket engine. The device includes a clamping assembly and an excitation assembly. The clamping assembly has a clamping portion capable of being fitted onto the workpiece under test and a plurality of limiting portions spaced circumferentially along the workpiece under test in the clamping portion. At least a portion of the excitation assembly is disposed in the limiting portions. The diameter of the clamping portion is adjustable so that it can be fitted onto workpieces of different diameters. Therefore, it possesses all the beneficial effects of the method, which will not be elaborated upon here.

[0054] This application also provides an electronic device, including a processor and a memory; the processor executes the steps in the embodiments by calling a program or instructions stored in the memory. Therefore, it possesses all the beneficial effects of the method, which will not be elaborated upon here. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0056] Figure 1This is a structural schematic diagram of the combustion chamber (known component) provided in Embodiment 1 of this application;

[0057] Figure 2 for Figure 1 Enlarged view of point A;

[0058] Figure 3 This is a schematic diagram showing the positional arrangement of the ultrasonic signal excitation components in the combustion chamber (known component) provided in Embodiment 1 of this application;

[0059] Figure 4 for Figure 3 Enlarged view of point B;

[0060] Figure 5 A schematic diagram of the structure of a combustion chamber (known component) with a known defect location provided in Embodiment 1 of this application;

[0061] Figure 6 This is a displacement cloud diagram obtained by circumferential excitation of a combustion chamber (known component) as provided in Embodiment 1 of this application;

[0062] Figure 7 This is a diagram showing the circumferential excitation of a combustion chamber (known component) as provided in Embodiment 1 of this application.

[0063] Figure 8 This is a displacement contour plot obtained by radial excitation of a combustion chamber (a known component) as provided in Embodiment 1 of this application;

[0064] Figure 9 The diagram showing the radial excitation of the combustion chamber (a known component) provided in Embodiment 1 of this application;

[0065] Figure 10 This is a displacement contour map obtained by axial excitation of a combustion chamber (known component) as provided in Embodiment 1 of this application;

[0066] Figure 11 An axial excitation diagram of a combustion chamber (known component) provided for Embodiment 1 of this application;

[0067] Figure 12 The axial energy flux density map of the T(0,1) mode guided wave provided in Embodiment 1 of this application;

[0068] Figure 13 The axial energy flux density map of the F(1,1) mode guided wave provided in Embodiment 1 of this application;

[0069] Figure 14 The axial energy flux density map of the L(0,1) mode guided wave provided in Embodiment 1 of this application;

[0070] Figure 15This is a radial displacement component diagram of the time-domain wave signal of a monitoring point containing a desoldering defect in Embodiment 2 of this application;

[0071] Figure 16 This is a time-domain waveform diagram showing the axial displacement components of a monitoring point containing a weld breakage defect in Embodiment 2 of this application.

[0072] Figure 17 The image shows the circumferential time-domain waveform components of the T(0,1) mode guided wave obtained by circumferential excitation in Example 2.

[0073] Figure 18 This is a simplified structural diagram of the clamping assembly provided in Embodiment 2.

[0074] Figure label:

[0075] 1-Excitation component; 2-Desoldering area; 3-Combustion chamber; 4-Limiting part; 5-Clamping part; 6-Probe. Detailed Implementation

[0076] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0077] The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application.

[0078] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0079] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0080] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0081] Example 1

[0082] In this embodiment, combined with Figures 1-17 This application describes a method for detecting weld defects in the thrust chamber of a rocket engine. This method is applicable to a weld defect detection device, which includes an excitation component 1. The excitation component 1 includes a transmitting module and a receiving module connected in communication.

[0083] The weld defect detection method includes: excitation step 100: the excitation component 1 is used on a known part with weld desoldering defects, and an ultrasonic signal is excited to the normal position of the weld of the known part through the transmitting module, and multiple guided wave mode groups are captured by the receiving module.

[0084] Specifically, the combustion chamber 3 of a common liquid oxygen-kerosene engine uses a copper alloy as the inner wall and high-strength steel as the outer wall. In this embodiment, a detailed description of the method for detecting weld debonding defects is given using a copper alloy-high-strength steel combined combustion chamber 3 (this combustion chamber 3 is the aforementioned known component) as an example. The geometry of the combustion chamber 3 is as follows: Figure 1 and Figure 2 As shown in Table 1; the dimensions of combustion chamber 3 are shown in Table 1.

[0085] Table 1: Dimensions of Combustion Chamber 3;

[0086]

[0087] Because combustion chamber 3 has a large radius of curvature and thin sidewalls, it is not easy to observe the details of its end face from its actual shape. Therefore, a supplementary end face diagram is provided to facilitate observation of the geometric features of the end face of combustion chamber 3. The end face of combustion chamber 3 is shown below. Figure 3 As shown, the inner layer is a copper milled groove inner wall, and the outer layer is a steel outer wall. The two layers are welded together to form a weld. The material parameters of the two materials are shown in Table 2.

[0088] Table 2: Material parameters of combustion chamber 3;

[0089] Material Young's modulus (GPa) Poisson's ratio <![CDATA[Density (kg / m 3 )]]> copper 200 0.3 8960 steel 210 0.3 7932

[0090] Specifically, ultrasonic signals are sequentially excited along the axial, circumferential and radial directions on the end face of combustion chamber 3 via a transmitting module, and the axial, circumferential and radial ultrasonic signal components are received by a receiving module (the transmitting module and the receiving module belong to excitation component 1; in other words, excitation component 1 adopts a self-transmitting and self-receiving mode).

[0091] Specifically, a Toneburst detection signal with a frequency of 100kHz and a period of 5 is used. This type of signal is commonly used in ultrasonic nondestructive testing and can excite guided waves with fewer modes and lower orders in the structure. This avoids the situation where guided waves with multiple modes and orders overlap with the reflected echoes caused by desoldering defects, making it difficult to distinguish them.

[0092] Specifically, in combination Figure 4 and Figure 5 As shown, in order to generate a stable guided wave that fully covers the circumference, the following steps are involved in determining the number of end-face excitations:

[0093] Step 101 for calculating the number of excitation components 1: Calculate the arc length of adjacent excitation components 1 along the circumferential direction according to formula (1);

[0094]

[0095] Where l represents the arc length of adjacent excitation components along the circumferential direction; λ is the wavelength of the excitation ultrasonic signal; d represents the diameter of the combustion chamber; n is the number of structural units on the end face of the combustion chamber; and h is the wall thickness of the combustion chamber.

[0096] The number of excitation components 1 is calculated according to formula (2):

[0097]

[0098] Where N represents the number of excitation components 1, and L is the perimeter of the known component along its axial cross section; [] indicates the number of excitation components 1. Round up;

[0099] Excitation position arrangement step 102: Arrange N excitation components 1 at a spacing of l on the axial section of the known component;

[0100] Step 103 for setting the excitation direction: Excite ultrasonic signals along the circumferential, radial, and axial directions of the known component through the N transmitting modules in the N excitation components 1 respectively; specifically, to excite a T(0,1) mode guided wave, select an ultrasonic signal to excite along the circumferential direction; to excite an F(1,1) mode guided wave, select an ultrasonic signal to excite along the radial direction; to excite an L(0,1) mode guided wave, select an ultrasonic signal to excite along the axial direction.

[0101] Guided wave mode group acquisition step 104: For the guided wave propagating along the axial direction of the combustion chamber 3 (known component), the receiving module can capture the L(a,b) type longitudinal wave mode group generated by axial excitation, the T(c,d) type torsional wave mode group generated by circumferential excitation, and the F(e,f) type bending wave mode group generated by radial excitation, according to the direction of particle vibration. Here, a, b, c, d, e, and f are all integers, a and c are both greater than or equal to 0, and b, d, f, and e are all greater than or equal to 1.

[0102] Specifically, excitation is added to the combustion chamber 3 (a known component) along the circumferential, radial, and axial directions according to step 101 of calculating the number of excitation components and step 102 of arranging the excitation positions. For guided waves propagating along the axial direction of the quasi-circular tube structure (here, the quasi-circular tube structure refers to the combustion chamber 3), they are divided into L(a,b) longitudinal wave mode group, T(c,d) torsional wave mode group, and F(e,f) bending wave mode group according to the direction of particle vibration.

[0103] Analysis and screening step 200: The guided wave of the T(0,1) mode generated by circumferential excitation, the guided wave of the F(1,1) mode generated by radial excitation, and the guided wave of the L(0,1) and F(1,1) modes generated by axial excitation are identified as excitable guided wave modes.

[0104] Specifically, taking the T(c,d) type torsional wave mode group as an example for analysis, c represents the circumferential order of the mode, and d represents the order of a certain mode group (c and d are both integers; c≥0, d≥1). For any structure, the higher-order modes in the T(0,d) mode group with d>1 have a cutoff frequency. When the excitation frequency is higher than the cutoff frequency of the higher-order mode, the higher-order modes will be generated sequentially. Therefore, this application selects low-frequency ultrasonic signals to avoid the occurrence of higher-order mode guided waves and prevent interference from detection; thus, it is finally determined that the F(1,1) type mode, L(0,1) type mode, and T(0,1) type mode can excite guided wave modes.

[0105] The above three excitable guided wave modes are applied to a known component with weld defects. The excitable guided wave mode that can determine the location of the weld defect in the known component and meets the screening criteria is calibrated as the target guided wave mode. Specifically, this application takes a combustion chamber 3 with a rectangular weld desoldering defect (this combustion chamber 3 with a rectangular weld desoldering defect can be understood as a known component with weld defects) as an example for illustration.

[0106] Specifically, the number of structural units with weld defects between the inner and outer walls is 5 (these 5 structural units refer to 5 cooling channels), corresponding to a circumferential arc length of 25mm. The axial weld debonding length of the 5 structural units is 25mm, and the weld debonding area 2 is as follows. Figure 6As shown. The size of the detached area 2 is very small relative to the structure of the combustion chamber 3, and it falls within the range of detached sizes that may occur in actual operating conditions.

[0107] Specifically, in combination Figures 7-11 As shown, the combustion chamber 3 structure of this application can excite guided waves of various modes, which need to be screened to determine the guided wave modes that can be used for weld debonding defect detection. The selection criteria for guided wave modes in this application are fourfold: excitability, mode purity, sensitivity to weld debonding defects, and energy flux density distribution along the wave propagation direction.

[0108] Excitability refers to the ability of guided wave modes within the structure to be excited and propagate stably. In this combustion chamber 3 structure, under the excitation of a low-frequency signal, guided waves of F-like (1,1), L-like (0,1), and T-like (0,1) modes are generated. The subsequent selection of guided wave modes will be based on these three modes.

[0109] Mode purity can be measured by the number of waveguide modes simultaneously excited in the structure. From Figure 9 It can be clearly observed that axial excitation can simultaneously generate F(1,1)-like and L(0,1)-like guided waves with low purity. The propagation of these two types of guided waves in the structure is relatively complex, and they may overlap with reflected echo signals caused by weld defects, making them difficult to observe. In contrast, radial excitation can produce F(1,1)-like guided waves with higher purity, making it easier to observe and analyze the ultrasonic signals in the structure.

[0110] Sensitivity to solder detachment defects refers to whether a guided wave, when passing through a solder detachment defect, will exhibit significant interaction with the defect and generate a large-amplitude reflected echo signal. From... Figures 7-9 In the comparative analysis, we can find that both the F(1,1) and T(0,1) mode waveguides are quite sensitive to desoldering defects. However, the circumferentially excited waveguide has a more scattered wave behind the T(0,1) mode waveguide, which makes it difficult to observe the reflected echo signal caused by desoldering defects.

[0111] The energy flux density distribution along the wave propagation direction refers to the energy transferred per unit time through a unit area perpendicular to the wave vector; it is the product of the wave's energy density and its propagation speed. Energy flux density simultaneously reflects both energy level and flow rate. Different waveguide modes exhibit differences in energy flux density along their wave propagation direction. Waveguide modes with higher energy flux density and concentrated distribution near the connection surface can be selected based on energy transfer characteristics. Here, a two-dimensional structural element of combustion chamber 3 is selected, and the energy flux density along the wave propagation direction for three modes can be obtained using the semi-analytical finite element method (SAFE) with 100kHz ultrasonic signal excitation, as shown below. Figures 12-14As shown, it can be observed that the F(1,1) mode guided wave exhibits a more concentrated energy flux density in the inner and outer wall connection area compared to the L(0,1) and T(0,1) modes, indicating that energy is relatively concentrated at the interface during ultrasonic wave propagation. When the structure is well-welded, the energy flux density at this connection surface is higher; when the structure is detached, the energy flux density at this connection surface is lower. Based on this energy flux density criterion in the propagation direction, it can be determined that the F(1,1) mode guided wave is more effective at detecting detachment defects compared to the other two modes.

[0112] Based on the above four screening criteria, the F(1,1)-like mode in the excitable waveguide mode can be identified as an excitable waveguide mode;

[0113] Inspection step 400: The test piece is inspected using a target guided wave mode to detect and determine the location of defects. Inspection step 400 also includes the following steps:

[0114] Application step 401: Apply the target guided wave pattern of type F(1,1) to the device under test;

[0115] Step 402: During the guided wave propagation process, when a reflected signal caused by a defect is detected, the distance between the defect location and the receiving module or transmitting module can be determined according to formula (3):

[0116]

[0117] Where v represents the propagation speed of the guided wave mode of the F(1,1) target (note that the meaning of v here is the same as the meaning of v in formula (1), but different definitions are used because the objects applied are different), Δt represents the time difference between the receiving module receiving the excitation signal and receiving the reflected signal caused by the defect, and X represents the distance between the defect location and the receiving module or the transmitting module.

[0118] To quantitatively measure the signal arrival time, both the excitation signal and the received reflected signal caused by the defect are subjected to Hilbert transform to obtain the signal envelope, thereby determining the signal peak time. In summary, this application proposes a method for detecting weld debonding defects in the weld between the inner and outer walls of the combustion chamber 3 using ultrasonic guided waves. Ultrasonic guided waves have advantages such as long propagation distance, accessibility of the probe 6 in the monitoring area, low requirements for the flatness of the outer wall weld surface, high detection efficiency, and low detection cost. In this application, ultrasonic signals are excited in each reinforced area of ​​the inner wall on the end face of the combustion chamber 3, forming a guided wave that completely covers the circumference and propagates stably along the axial direction within the combustion chamber 3 structure. When the guided wave propagates to the weld debonding area 2, the guided wave sensitive to the weld debonding defect interacts with the defect, causing partial reflection of the ultrasonic signal. Four guided wave mode screening criteria are used to determine the suitable guided wave mode for detecting weld debonding defects. Based on this, a piezoelectric transducer clamped in a variable cross-section clamping assembly is used to excite and receive ultrasonic signals using the pulse-echo method. By analyzing the composition of the ultrasonic signal, the welding condition of the inner and outer walls of the milled groove is determined and the location of the weld debonding defect is identified.

[0119] Example 2

[0120] In this embodiment, combined with Figure 18 As shown, a weld defect detection device for a liquid rocket engine is provided. The weld defect detection device includes a clamping assembly and an excitation assembly 1. The clamping assembly has a clamping part that can be fitted onto the workpiece under test and a plurality of limiting parts 4 arranged circumferentially on the clamping part. At least a portion of the excitation assembly 1 is disposed on the limiting parts 4. The diameter of the clamping part 5 is adjustable so that the clamping part 5 can be fitted onto workpieces under test with different diameters.

[0121] Specifically, the excitation component 1 includes a radially polarized piezoelectric transducer; the radially polarized piezoelectric transducer includes a transmitting module and a receiving module connected in communication.

[0122] Specifically, the clamping assembly includes a tracked clamp with an adjustable diameter.

[0123] More specifically, based on Embodiment 1, this application extracts the time-domain waveform components for radial excitation. Radial polarized piezoelectric transducers or electromagnetic ultrasonic transducers can be used for excitation and reception of radial ultrasonic signals.

[0124] Furthermore, if an electromagnetic ultrasonic transducer is used to excite and receive radial ultrasonic signals, a coil is wound in the side wall region near the end face, and magnets are uniformly arranged circumferentially above the coil. A variable current is passed through the coil to excite a radially excited ultrasonic signal that propagates axially.

[0125] Furthermore, if radially polarized piezoelectric transducers are used to generate radial vibrations, arranging radially polarized piezoelectric transducers at multiple points on the end face of combustion chamber 3 can excite guided waves of the F(1,1) mode that completely cover the circumference. As described in Embodiment 1, one excitation signal needs to be added for every two structural units, requiring at least 150 radially polarized piezoelectric transducers evenly distributed circumferentially to excite guided waves that completely cover the circumference. Here, one excitation signal is added to each structural unit.

[0126] Furthermore, since different liquid rocket engine combustion chambers 3 have different end face diameters, to improve the adaptability of radially polarized piezoelectric transducers to combustion chambers 3 of different sizes, the radially polarized piezoelectric transducers are specifically arranged in a variable-size clamping assembly. When it is necessary to detect weld debonding defects for combustion chambers 3 of different sizes, the number of radially polarized piezoelectric transducers can be determined according to the calculation formula for determining the number of excitations. A tracked clamp with a variable circumferential length is used to clamp the radially polarized piezoelectric transducers, which are then arranged on the end face of the combustion chamber 3, and a coupling agent is applied to the contact surface for rapid detection of weld debonding defects. If radially polarized piezoelectric transducers are used for ultrasonic signal excitation and reception, radial displacement signal excitation is also required in each inner wall stiffened area. Based on this, the received time-domain wave signal is analyzed for signal components, such as... Figure 15 and Figure 16 Analysis reveals that the waveform signal at t=0 is an incident wave signal with 5 periods, and the waveform signal at t=0.46ms is the reflected signal obtained after the incident wave is reflected by the bottom surface. A more obvious waveform signal can be observed around t=0.23ms, which is the reflected echo signal caused by the guided wave passing through the weld debonding defect. Furthermore, this weld debonding defect is located in the middle of the combustion chamber's 3-axis direction, and its propagation time is consistent with the basic understanding that the arrival time of the reflected echo caused by the weld debonding defect is half the arrival time of the bottom surface reflected echo. A smaller amplitude wave signal exists in the latter part of the reflected echo caused by the weld debonding defect, because the reflected echo caused by the weld debonding defect propagates back in the opposite direction after reaching the signal excitation end face. From, as... Figure 15 and Figure 16 The reflected echo caused by the desoldering defect can be clearly observed. The specific location of the desoldering defect can be easily determined by the propagation time and the speed of ultrasonic wave propagation in combustion chamber 3. During guided wave propagation, let the propagation speed of the F(1,1) mode guided wave be v, the time difference between the receiving unit receiving the excitation signal and the reflected signal caused by the defect be Δt, and the distance between the excitation module and the receiving module be x0. When using a self-excitation and self-receiving method, x0 = 0. If the reflected signal caused by the defect is detected, the distance between the defect location and the excitation / receiving location is...

[0127] Furthermore, the distance between the simulated desoldering defect and the excitation / receiving position is 0.25m. The specific implementation process for locating the defect is as follows:

[0128] The peak arrival time of the radial displacement component excitation signal is 0.0261 ms, the peak arrival time of the defect reflection signal is 0.26424 ms, Δt = 0.23816 ms, the corresponding distance vΔt = 0.24670 m, the error is 0.0033 m, and the relative error is 1.3%.

[0129] The peak arrival time of the axial displacement component excitation signal is 0.02658 ms, the peak arrival time of the defect reflection signal is 0.26322 ms, Δt = 0.23664 ms, the corresponding distance vΔt = 0.24512 m, the error is 0.0049 m, and the relative error is 2.0%.

[0130] After multiple experiments, the detection accuracy of this application can reach the weld detachment area 2 with a weld seam and a detachment length of 25mm. This detachment size is very small relative to the size of the combustion chamber 3, and it is very sensitive to detachment defects, showing the advantage of this detection method compared with other non-destructive testing methods.

[0131] It is worth noting that the above method uses an F(1,1)-like pattern to detect weld failure defects between the inner and outer walls of the combustion chamber's 3 milled groove; combined with Figure 18 Furthermore, this application can also use a T(0,1)-like mode to detect weld debonding defects. The circumferential excitation method also shows relatively clear ultrasonic echo signals caused by weld debonding defects.

[0132] In summary, the ultrasonic guided wave detection method for detecting weld debonding defects between the inner and outer walls of the milled groove in the combustion chamber 3, which uses incident light along the end face, has advantages over the commonly used ultrasonic bulk wave detection method that uses an ultrasonic probe 6 arranged on the side wall. It offers higher detection efficiency and eliminates the need to consider the accessibility of the probe 6 and the flatness of the outer wall surface. Compared to the detection method proposed in this paper, traditional X-ray detection, due to its complex structure and strong scattered signal, is not conducive to imaging fine structures such as welds, making it difficult to judge welding quality. Furthermore, compared to laser holographic detection, the ultrasonic detection method proposed in this paper has lower detection cost, higher detection efficiency, and is simpler and more sensitive for time-domain signal detection at the end face of the combustion chamber 3.

[0133] Example 3

[0134] This embodiment provides an electronic device, including a processor and a memory; the processor executes the steps in the embodiment by calling programs or instructions stored in the memory. Therefore, it possesses all the beneficial effects of Embodiment 1, which will not be elaborated upon further here.

[0135] Example 4

[0136] This embodiment provides a computer-readable storage medium storing a program or instructions that cause a computer to perform the steps in Embodiment 1. Therefore, it possesses all the beneficial effects of Embodiment 1, which will not be elaborated upon further here.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for detecting weld defects in the thrust chamber of a rocket engine, the method being applicable to a weld defect detection device, the device comprising an excitation assembly, the excitation assembly comprising a transmitting module and a receiving module connected in communication; the method comprising: Excitation steps: The excitation component is used on a known part with weld defects, and an ultrasonic signal is excited at the normal position of the weld of the known part through the transmitting module. Multiple guided wave mode groups are captured by the receiving module. The excitation step is characterized by comprising the following steps: Steps for calculating the number of excitation components: Calculate the arc length of adjacent excitation components along the circumferential direction according to formula (1); （1） in, This represents the arc length of adjacent excitation components along the circumferential direction; The wavelength for exciting the ultrasonic signal; Indicates the diameter of the combustion chamber; This refers to the number of structural units on the end face of the combustion chamber. For the thickness of the combustion chamber wall; The number of excitation components is calculated according to formula (2): （2） in, Indicates the number of the excitation components. Let be the perimeter of the known component along its axial cross section; Excitation position arrangement steps: The excitation components are as follows The spacing is arranged on the axial section of the known component; Steps to set the incentive direction: via In the aforementioned excitation components Each of the aforementioned transmitting modules excites ultrasonic signals along the circumferential, radial, and axial directions of the known component, respectively; Guided wave mode group acquisition step: For a guided wave propagating along the axis of the known component, the receiving module can capture the L(a,b) type longitudinal wave mode group generated by axial excitation, the T(c,d) type torsional wave mode group generated by circumferential excitation, and the F(e,f) type bending wave mode group generated by radial excitation, according to the particle vibration direction, where a, b, c, d, e, and f are all integers, a and c are both greater than or equal to 0, and b, d, f, and e are all greater than or equal to 1; The method for detecting weld defects includes the following steps after the activation step: Analysis and screening steps: Multiple guided wave modes captured by the receiving module and excited along different directions are used in a known component with weld defects. The guided wave modes that can determine the location of the weld defects in the known component and meet the screening criteria are designated as target guided wave modes. The screening criteria in this step specifically include the following steps: The excitability criterion is adopted: excitability refers to whether an ultrasonic guided wave can be excited and stably propagated in the known component; The mode purity criterion is adopted: mode purity refers to the number of guided wave modes that can be simultaneously excited in the known components; the fewer the number of guided wave modes that can be simultaneously excited, the higher the mode purity. The sensitivity criterion for solder detachment defects is adopted: the sensitivity to solder detachment defects is to determine whether the wave will interact with the solder detachment defect when it passes through the defect and cause a large amplitude reflected echo signal. The energy flux density distribution criterion in the wave propagation direction is adopted: the energy flux density distribution in the wave propagation direction refers to the energy transferred per unit time through a unit area perpendicular to the wave propagation direction; The above criteria can be used to identify the F(1,1)-like guided wave generated by radial excitation as the target guided wave mode. Detection steps: Use the target guided wave mode to detect the test piece, so as to detect and determine the location of the defect in the test piece.

2. The method for detecting defects in the thrust chamber weld of a rocket engine according to claim 1, characterized in that, The analysis and screening steps include the following steps: The guided waves of the T(0,1) mode generated by circumferential excitation, the F(1,1) mode generated by radial excitation, and the L(0,1) and F(1,1) modes generated by axial excitation are subjected to mode screening. The screening criteria include the following steps: Based on the excitability criterion, guided waves of the T(0,1) mode generated by circumferential excitation, guided waves of the F(1,1) mode generated by radial excitation, and guided waves of the L(0,1) and F(1,1) modes generated by axial excitation are identified as excitable guided waves.

3. The method for detecting defects in the weld seam of a rocket engine thrust chamber according to claim 1, characterized in that, The detection steps include the following steps: Application steps: Apply the target waveguide mode of type F(1,1) to the device under test; Determination steps: During the guided wave propagation process, when a reflected signal caused by a defect is detected, the distance between the defect location and the receiving module or the transmitting module can be determined according to formula (3): （3） in, This represents the time difference between when the receiving module receives the excitation signal and when it receives the reflected signal caused by the defect. This indicates the distance between the defect location and the receiving module or the transmitting module.

4. A device for detecting weld defects in the thrust chamber of a rocket engine, applied to the weld defect detection method described in claim 1 or 3, characterized in that, The weld defect detection device includes a clamping assembly and an excitation assembly; The clamping assembly has a clamping portion that can be sleeved on the test piece and a plurality of limiting portions that are spaced apart along the circumference of the test piece in the clamping portion; at least a portion of the excitation assembly is disposed in the limiting portion; The diameter of the clamping part is adjustable so that the clamping part can be fitted onto the test piece of different diameters.

5. The detection device for weld defects in the thrust chamber of a rocket engine according to claim 4, characterized in that, The excitation assembly includes a radially polarized piezoelectric transducer; The radially polarized piezoelectric transducer includes a transmitting module and a receiving module with communication connections.

6. The detection device for weld defects in the thrust chamber of a rocket engine according to claim 5, characterized in that, The clamping assembly includes a tracked clamp with an adjustable diameter.

7. An electronic device, characterized in that, include: Processor and memory; The processor executes the steps of the method as described in any one of claims 1 to 3 by invoking programs or instructions stored in the memory.

Images