Uncalibrated stress measurement method and device based on ultrasonic longitudinal wave and incremental deformation mechanics

Abstract

The invention discloses an uncalibrated stress measurement method and device based on ultrasonic longitudinal wave and incremental deformation mechanics, and relates to the technical field of ultrasonic nondestructive testing, and the method comprises the steps: obtaining an ultrasonic longitudinal wave time domain signal at a detection point of a to-be-detected test piece and the thickness of the to-be-detected test piece; determining the propagation time of the longitudinal wave in the test piece to be detected based on the ultrasonic longitudinal wave time domain signal; based on the thickness of the to-be-detected test piece and the propagation time, determining the propagation speed of the ultrasonic longitudinal wave in the to-be-detected test piece; and determining a stress value at the detection point of the test piece to be detected according to the propagation velocity. According to the invention, the problem of measuring the high-order elastic constant of the material can be avoided, and the dependence of a stress measurement result on a calibration result is avoided.

Description

Technical Field

[0001] This application relates to the field of ultrasonic nondestructive testing technology, and in particular to a calibration-free stress measurement method and device based on ultrasonic longitudinal waves and incremental deformation mechanics. Background Technology

[0002] In modern industrial equipment, key components or structures face complex stress conditions such as pressure and load during manufacturing and use, making them highly susceptible to stress concentration. In particular, uniaxial stress often exists in shaft or rod parts such as bolts, affecting preload reliability, structural dimensional stability, and consequently, the mechanical properties and service life of the entire equipment and its functional components. Therefore, it is essential to detect and assess the level of uniaxial stress in workpieces. Stress measurement technology, as one of the core means of product quality control, safety assessment, and risk prevention, is of paramount importance.

[0003] Currently, there are various stress testing methods. Among them, ultrasonic testing methods have been widely used in the field of non-destructive stress state assessment due to their relatively simple equipment structure, fast testing speed, and non-destructive and non-radioactive characteristics. Existing ultrasonic stress measurement methods based on the acoustoelastic effect are usually based on constitutive relation models that include third-order elastic constants. Since the solution process of such models is highly dependent on higher-order elastic parameters, which are difficult to obtain through direct measurement, existing technologies generally require calibration to obtain the required parameters, thus affecting the applicability and scalability of stress testing methods.

[0004] In existing technologies, a bolt axial stress analysis model is obtained by using a standard bolt to send and receive signal waves, and the stress measurement results are calibrated to reduce measurement errors in the bolt stress monitoring process. However, this method still cannot avoid the dependence of bolt stress measurement results on calibration results.

[0005] In addition, the stress measurement methods provided in the existing technology still require calibration of bolts with the same material and heat treatment method as the bolts being measured to measure the double-wave stress coefficient in order to realize the measurement of bolt stress.

[0006] Therefore, how to circumvent the difficulty of determining the higher-order elastic constants of materials, while avoiding the dependence of stress measurement results on calibration results, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this application is to provide a calibration-free stress measurement method and device based on ultrasonic longitudinal waves and incremental deformation mechanics, which can avoid the difficulty of determining the higher-order elastic constants of materials, and at the same time avoid the dependence of stress measurement results on calibration results.

[0008] To achieve the above objectives, this application provides the following solution.

[0009] In a first aspect, this application provides a calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics, the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics includes the following steps.

[0010] The ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen at the test point are obtained.

[0011] Based on the ultrasonic longitudinal wave time-domain signal, the propagation time of the longitudinal wave in the test specimen is determined.

[0012] Based on the thickness of the test specimen and the propagation time, the propagation speed of the ultrasonic longitudinal wave in the test specimen is determined.

[0013] Based on the propagation speed, the stress value at the test point of the specimen to be tested is determined.

[0014] Optionally, the formula for calculating the propagation speed is as follows.

[0015] v p = d / t .

[0016] in, v p For the speed of transmission; d The thickness of the test specimen; t This refers to the propagation time of the ultrasonic longitudinal wave at the test point of the specimen to be tested.

[0017] Optionally, the stress value at the test point of the specimen to be tested is determined based on the propagation speed, specifically including the following steps.

[0018] Based on incremental deformation theory and combined with the propagation characteristics of longitudinal waves under stress, the governing equations of longitudinal waves under stress are determined.

[0019] Based on the longitudinal wave control equation under stress and the propagation velocity of the ultrasonic longitudinal wave in the test specimen, the stress calculation formula is determined.

[0020] Based on the stress calculation formula, the stress value at the test point of the specimen to be tested is determined.

[0021] Optionally, the expression for the longitudinal wave control equation under stress is shown below.

[0022] .

[0023] in, S zz This is stress data; λ This is the first Lamé coefficient, which is related to the material's resistance to volumetric deformation. μ The second Lamé coefficient, also known as the shear modulus, is used to measure a material's ability to resist shear deformation. ρ The density of the material; u z This represents the component of the plane wave displacement along the z-axis. t The propagation time of the ultrasonic longitudinal wave at the test point of the specimen under test; x z To find the direction of the derivative, that is, the rate of change of the field quantity along the corresponding coordinate direction.

[0024] Optionally, the stress calculation formula is as follows.

[0025] .

[0026] in, S zz This is stress data; λ This is the first Lamé coefficient, which is related to the material's resistance to volumetric deformation. μ The second Lamé coefficient, also known as the shear modulus, is used to measure a material's ability to resist shear deformation. ρ The density of the material; v p For the speed of transmission.

[0027] Secondly, this application provides a calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics. The calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics is used to implement the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics as described in any one of the first aspects. The calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics includes: a longitudinal wave excitation sensor, a longitudinal wave receiving sensor, and a processing unit.

[0028] The longitudinal wave excitation sensor is used to emit ultrasonic longitudinal waves as excitation signals at the detection point of the test specimen under applied stress.

[0029] The longitudinal wave receiving sensor is used to acquire the ultrasonic longitudinal wave time-domain signal at the test point of the specimen under test.

[0030] The processing unit is used to determine the propagation time of the longitudinal wave in the test specimen based on the ultrasonic longitudinal wave time-domain signal; to determine the propagation speed of the ultrasonic longitudinal wave in the test specimen based on the thickness of the test specimen and the propagation time of the longitudinal wave in the test specimen; and to determine the stress value at the test point of the test specimen based on the propagation speed of the ultrasonic longitudinal wave in the test specimen.

[0031] Thirdly, this application provides a calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics. The calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics is used to implement the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics as described in any of the first aspects. The calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics includes the following modules.

[0032] The data acquisition module is used to acquire the ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen at the test point.

[0033] The propagation time determination module is used to determine the propagation time of the longitudinal wave in the test specimen based on the ultrasonic longitudinal wave time domain signal.

[0034] The propagation speed determination module is used to determine the propagation speed of the ultrasonic longitudinal wave in the test specimen based on the thickness of the test specimen and the propagation time.

[0035] The stress value determination module is used to determine the stress value at the test point of the specimen under test based on the propagation speed.

[0036] Fourthly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics as described in the first aspect.

[0037] Fifthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics as described in the first aspect.

[0038] In a sixth aspect, this application provides a computer program product, including a computer program that, when executed by a processor, implements the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics as described in the first aspect.

[0039] Based on the specific embodiments provided in this application, the following technical effects are disclosed.

[0040] This application provides a calibration-free stress measurement method and apparatus based on ultrasonic longitudinal waves and incremental deformation mechanics. The method includes: acquiring the time-domain signal of the ultrasonic longitudinal wave at a test point and the thickness of the test specimen; providing core raw data support for subsequent stress measurement and ensuring a reliable data source for the measurement process. Based on the ultrasonic longitudinal wave time-domain signal, the propagation time of the longitudinal wave in the test specimen is determined; key parameters of longitudinal wave propagation are accurately extracted, and interference information in the time-domain signal is eliminated, providing an accurate basis for subsequent propagation velocity calculation. Based on the thickness of the test specimen and the propagation time, the propagation velocity of the ultrasonic longitudinal wave in the test specimen is determined; through reasonable calculation of basic parameters, a correlation between thickness, propagation time, and propagation velocity is established, achieving accurate derivation of the propagation velocity and building a crucial bridge between raw data and stress values. Based on the propagation velocity, the stress value at the test point of the test specimen is determined; relying on the mechanical correlation between the ultrasonic longitudinal wave propagation velocity and stress, quantitative characterization of the stress at the test point is achieved, realizing the core objective of accurate stress measurement. This application, through step-by-step connection and derivation, uses ultrasonic longitudinal wave signals and specimen thickness as a basis to sequentially obtain propagation time and propagation speed and finally determine stress value. The whole process can avoid the difficulty of determining higher-order elastic constants of materials, and at the same time avoid the dependence of stress measurement results on calibration results. It can achieve accurate and reliable measurement of stress at the test point of the specimen under test, and ensure the scientificity and practicality of stress measurement results. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is an application environment diagram of a calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics in one embodiment of this application.

[0043] Figure 2 This is a flowchart illustrating a calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics, provided as an embodiment of this application.

[0044] Figure 3 This is a schematic diagram of a calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics, provided as an embodiment of this application.

[0045] Figure 4 This is a schematic diagram of a calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics, provided as another embodiment of this application.

[0046] Figure 5 This is a flowchart illustrating a calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics, provided as another embodiment of this application.

[0047] Figure 6 A schematic diagram showing the comparison between stress measurement results and applied stress provided for another embodiment of this application.

[0048] Figure 7 This is a schematic diagram of the functional modules of an uncalibrated stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics, provided as an embodiment of this application.

[0049] Figure 8 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] To address the limitations of current ultrasonic stress measurement methods based on acoustoelastic effects, this application innovatively proposes a calibration-free stress measurement method and apparatus based on ultrasonic longitudinal waves and incremental deformation mechanics, grounded in incremental deformation mechanics theory. Unlike existing methods, this method does not require calibration of the ultrasonic wave transit time using a zero-stress specimen, thus avoiding the dependence of stress measurement results on calibration results. Furthermore, this method does not require the measurement of third-order elastic constants, effectively overcoming the dependence on third-order elastic constants during stress measurement. Therefore, the method and apparatus of this application have significant engineering application value, enabling more accurate and convenient measurement of the stress state of key components or structures in modern industrial equipment.

[0052] This method utilizes the propagation characteristics of longitudinal waves under stress in prestressed media and, based on incremental deformation mechanics theory, derives the correspondence between longitudinal wave velocity and stress, thereby achieving non-destructive measurement of structural stress state. Compared with traditional ultrasonic stress measurement methods based on acoustoelastic effects, this application avoids the difficulty of determining higher-order elastic constants of materials and avoids the dependence of stress measurement results on calibration results. It plays an important role in the field of non-destructive testing of stress state and represents an innovative extension of existing ultrasonic stress non-destructive testing technology.

[0053] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] The calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics provided in this application can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be set up independently, integrated into server 104, or placed in the cloud or on another server. Terminal 102 can send the acquired ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen at the test point to server 104. After receiving the ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen, server 104, based on the ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen, determines the propagation time of the longitudinal wave in the test specimen; based on the thickness of the test specimen and the propagation time, determines the propagation speed of the ultrasonic longitudinal wave in the test specimen; and based on the propagation speed, determines the stress value at the test point of the test specimen. Server 104 can feed back the obtained stress value at the test point of the test specimen to terminal 102. Furthermore, in some embodiments, the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics can also be implemented independently by the server 104 or the terminal 102. For example, the terminal 102 can directly perform calibration-free stress measurement based on ultrasonic longitudinal waves and incremental deformation mechanics on the ultrasonic longitudinal wave time domain signal and the thickness of the test specimen at the test point. Alternatively, the server 104 can obtain the ultrasonic longitudinal wave time domain signal and the thickness of the test specimen at the test point from the data storage system, and perform calibration-free stress measurement based on ultrasonic longitudinal waves and incremental deformation mechanics on the ultrasonic longitudinal wave time domain signal and the thickness of the test specimen at the test point.

[0055] The terminal 102 can be, but is not limited to, various desktop computers, laptops, smartphones, and tablets. The server 104 can be implemented using a standalone server or a server cluster consisting of multiple servers, or it can be a cloud server.

[0056] In one exemplary embodiment, such as Figure 2 As shown, a calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics is provided. This method is executed by a computer device, specifically a terminal or server, or both. In this embodiment, the method is applied to... Figure 1 Taking server 104 as an example, the following steps are included.

[0057] S1: Obtain the ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen at the test point.

[0058] S2: Based on the ultrasonic longitudinal wave time-domain signal, determine the propagation time of the longitudinal wave in the test specimen.

[0059] S3: Determine the propagation speed of the ultrasonic longitudinal wave in the test specimen based on the thickness of the specimen and the propagation time.

[0060] S4: Determine the stress value at the test point of the test piece based on the propagation speed.

[0061] By implementing steps S1 to S4 above, this application avoids the difficulty of determining the higher-order elastic constants of materials and avoids the dependence of stress measurement results on calibration results. It plays an important role in the field of stress state non-destructive testing and is an innovative extension of existing ultrasonic stress non-destructive testing technology.

[0062] As an optional implementation, the formula for calculating the propagation speed is as follows.

[0063] v p = d / t .

[0064] in, v p For the speed of transmission; d The thickness of the test specimen; t This refers to the propagation time of the ultrasonic longitudinal wave at the test point of the specimen to be tested.

[0065] As an optional implementation, in step S4, the stress value at the test point of the specimen to be tested is determined according to the propagation speed, specifically including the following steps.

[0066] S41: Based on the incremental deformation theory and combined with the propagation characteristics of longitudinal waves under stress, the longitudinal wave control equation under stress is determined; the expression of the longitudinal wave control equation under stress is shown below.

[0067] .

[0068] in, S zz This is stress data; λ This is the first Lamé coefficient, which is related to the material's resistance to volumetric deformation. μ The second Lamé coefficient, also known as the shear modulus, is used to measure a material's ability to resist shear deformation. ρ The density of the material; u z This represents the component of the plane wave displacement along the z-axis. t The propagation time of the ultrasonic longitudinal wave at the test point of the specimen under test; x zTo find the direction of the derivative, that is, the rate of change of the field quantity along the corresponding coordinate direction.

[0069] S42: Based on the longitudinal wave control equation under stress and the propagation velocity of the ultrasonic longitudinal wave in the test specimen, determine the stress calculation formula; the stress calculation formula is shown below.

[0070] .

[0071] in, S zz This is stress data; λ This is the first Lamé coefficient, which is related to the material's resistance to volumetric deformation. μ The second Lamé coefficient, also known as the shear modulus, is used to measure a material's ability to resist shear deformation. ρ The density of the material; v p For the speed of transmission.

[0072] S43: Based on the stress calculation formula, determine the stress value at the test point of the test piece.

[0073] The specific implementation steps of this method are as follows.

[0074] (1) Establish the longitudinal wave control equation under stress.

[0075] During stress measurement, based on incremental deformation theory and combined with the propagation characteristics of longitudinal waves under stress (the direction of particle vibration is parallel to the direction of wave propagation during the propagation of longitudinal waves), the governing equation of longitudinal waves under stress is established.

[0076] .

[0077] in, S zz This is stress data; λ This is the first Lamé coefficient, which is related to the material's resistance to volumetric deformation. μ The second Lamé coefficient, also known as the shear modulus, is used to measure a material's ability to resist shear deformation. ρ The density of the material; u z This represents the component of the plane wave displacement along the z-axis. t The propagation time of the ultrasonic longitudinal wave at the test point of the specimen under test; x z To find the direction of the derivative, that is, the rate of change of the field quantity along the corresponding coordinate direction.

[0078] (2) Determine the stress calculation formula.

[0079] .

[0080] in, S zz This is stress data; λ This is the first Lamé coefficient, which is related to the material's resistance to volumetric deformation. μ The second Lamé coefficient, also known as the shear modulus, is used to measure a material's ability to resist shear deformation. ρ The density of the material; v p For the speed of transmission.

[0081] According to the stress detection method in the above embodiment, the ultrasonic longitudinal wave velocity is measured, and the magnitude of the stress can be solved according to the specific calculation formula of the stress, which avoids the problem of determining higher-order elastic constants and has no calibration dependence.

[0082] In one exemplary embodiment, such as Figure 3 As shown, a calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics is provided. The device includes a longitudinal wave excitation sensor, a longitudinal wave receiving sensor, and a processing unit (not shown in the figure).

[0083] The longitudinal wave excitation sensor is used to emit ultrasonic longitudinal waves as excitation signals at the detection point of the test specimen under applied stress.

[0084] The longitudinal wave receiving sensor is used to acquire the ultrasonic longitudinal wave time-domain signal at the test point of the specimen under test.

[0085] The processing unit is used to determine the propagation time of the longitudinal wave in the test specimen based on the ultrasonic longitudinal wave time-domain signal; to determine the propagation speed of the ultrasonic longitudinal wave in the test specimen based on the thickness of the test specimen and the propagation time of the longitudinal wave in the test specimen; and to determine the stress value at the test point of the test specimen based on the propagation speed of the ultrasonic longitudinal wave in the test specimen.

[0086] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0087] Example 1: As Figure 4 As shown, this application provides a calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics. The device includes: a longitudinal wave sensor ( Figure 4The detection was performed using a single longitudinal wave sensor with self-excitation and self-reception. If two sensors were used, they would need to be positioned on opposite sides of the test specimen. The longitudinal wave sensor is used to: emit an ultrasonic longitudinal wave as an excitation signal at the detection point of the test specimen under applied stress; the longitudinal wave sensor is also used to acquire the time-domain signal of the ultrasonic longitudinal wave under stress; the ultrasonic longitudinal wave time-domain signal acquired by the longitudinal wave sensor is used to determine the propagation time of the longitudinal wave in the test specimen; the propagation time acquired by the longitudinal wave sensor is used to determine the propagation speed of the ultrasonic longitudinal wave in the test specimen under stress, and the propagation speed is used to determine the stress value.

[0088] Example 2: Figure 5 As shown, this application also provides a calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics. The calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics is applied to the above-mentioned stress measurement device. The stress measurement method specifically includes the following steps.

[0089] Step 201: Use a longitudinal wave sensor to excite an ultrasonic longitudinal wave signal. At the same time, use the longitudinal wave sensor to acquire the ultrasonic longitudinal wave time domain signal at the test point of the specimen under test.

[0090] In practical applications, the longitudinal wave sensor receives the following signal: u = y ( t ).

[0091] in, u The time-domain signal of the ultrasonic longitudinal wave acquired by the longitudinal wave sensor; t This refers to the propagation time of the ultrasonic longitudinal wave at the test point of the specimen to be tested.

[0092] Step 202: Calculate the propagation speed of the ultrasonic longitudinal wave by using the thickness of the test specimen and the propagation time of the ultrasonic longitudinal wave time domain signal collected by the longitudinal wave sensor.

[0093] In practical applications, step 202 specifically includes: obtaining the thickness at the detection point of the test specimen; dividing the thickness value at the detection point by the propagation time of the ultrasonic longitudinal wave time-domain signal acquired by the longitudinal wave sensor to obtain the ultrasonic longitudinal wave velocity. v p = d / t ;in, v p For the speed of transmission; d The thickness of the test specimen; t This refers to the propagation time of the ultrasonic longitudinal wave at the test point of the specimen to be tested.

[0094] Step 203: Determine the stress value based on the wave velocity of the ultrasonic longitudinal wave.

[0095] In practical applications, the test specimen is tested to obtain the ultrasonic longitudinal wave time-domain signal and thickness at the test point. The ultrasonic longitudinal wave velocity is obtained using the method proposed in this application and then incorporated into the stress calculation formula. The magnitude of the uniaxial stress is obtained.

[0096] The diagram showing the comparison between the stress measurement results and the applied stress provided in this application is shown below. Figure 6 As shown.

[0097] In summary, the longitudinal wave sensor emits an ultrasonic longitudinal wave as an excitation signal at the detection point of the test specimen under stress; the longitudinal wave sensor acquires the time-domain signal of the ultrasonic longitudinal wave under stress; the propagation time of the ultrasonic longitudinal wave acquired by the longitudinal wave sensor in the test specimen is obtained; the propagation speed of the ultrasonic longitudinal wave in the test specimen under stress is determined; and the stress value is determined based on the propagation speed.

[0098] This application has the following advantages: 1) Compared with traditional acoustoelastic stress measurement methods, this method does not require the determination of higher-order elastic constants of the material under test; 2) This method does not require calibration of the stress measurement results and can realize the measurement of absolute stress of the test piece; 3) This method can realize the measurement of absolute stress of shaft / rod structures. This invention plays an important role in the field of non-destructive testing of absolute stress states of shaft / rod structures and is an innovative extension of existing ultrasonic stress non-destructive testing technology.

[0099] Based on the same inventive concept, this application also provides a calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics for implementing the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics described above. The solution provided by this system is similar to the solution described in the above method. Therefore, the specific limitations of one or more calibration-free stress measurement system embodiments based on ultrasonic longitudinal waves and incremental deformation mechanics provided below can be found in the limitations of the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics described above, and will not be repeated here.

[0100] In one exemplary embodiment, such as Figure 7 As shown, a calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics is provided. The calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics includes the following modules.

[0101] The data acquisition module is used to acquire the ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen at the test point.

[0102] The propagation time determination module is used to determine the propagation time of the longitudinal wave in the test specimen based on the ultrasonic longitudinal wave time domain signal.

[0103] The propagation speed determination module is used to determine the propagation speed of the ultrasonic longitudinal wave in the test specimen based on the thickness of the test specimen and the propagation time.

[0104] The stress value determination module is used to determine the stress value at the test point of the specimen under test based on the propagation speed.

[0105] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 8 As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operating system and computer programs in the non-volatile storage media to run. The database stores the ultrasonic longitudinal wave time-domain signal at the test point of the specimen and the thickness information of the specimen. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics.

[0106] Those skilled in the art will understand that Figure 8 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0107] In one exemplary embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the above-described method embodiments.

[0108] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the above-described method embodiments.

[0109] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the above-described method embodiments.

[0110] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0111] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0112] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0113] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics, characterized in that, The calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics includes: Obtain the ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen at the test point; Based on the ultrasonic longitudinal wave time domain signal, the propagation time of the longitudinal wave in the test specimen is determined; Based on the thickness of the test specimen and the propagation time, the propagation speed of the ultrasonic longitudinal wave in the test specimen is determined; Based on the propagation speed, the stress value at the test point of the specimen to be tested is determined.

2. The calibration-free stress measurement method based on ultrasonic longitudinal wave and incremental deformation mechanics according to claim 1, characterized in that, The formula for calculating the propagation speed is: v p = d / t ； in, v p For the speed of transmission; d The thickness of the test specimen; t This refers to the propagation time of the ultrasonic longitudinal wave at the test point of the specimen to be tested.

3. The calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics according to claim 1, characterized in that, Based on the propagation speed, the stress value at the test point of the specimen to be tested is determined, specifically including: Based on the incremental deformation theory and combined with the longitudinal wave propagation characteristics under stress, the longitudinal wave control equation under stress is determined. Based on the longitudinal wave control equation under stress and the propagation velocity of the ultrasonic longitudinal wave in the test specimen, the stress calculation formula is determined. Based on the stress calculation formula, the stress value at the test point of the specimen to be tested is determined.

4. The calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics according to claim 3, characterized in that, The expression for the longitudinal wave control equation under stress is as follows: ； in, S zz For stress data; λ This is the first Lamé coefficient, which is related to the material's resistance to volumetric deformation. μ The second Lamé coefficient, also known as the shear modulus, is used to measure a material's ability to resist shear deformation. ρ The density of the material; u z This represents the component of the plane wave displacement along the z-axis. t The propagation time of the ultrasonic longitudinal wave at the test point of the specimen under test; x z The direction of the derivative is the rate of change of the field quantity along the corresponding coordinate direction.

5. The calibration-free stress measurement method based on ultrasonic longitudinal wave and incremental deformation mechanics according to claim 3, characterized in that, The stress calculation formula is as follows: ； in, S zz For stress data; λ This is the first Lamé coefficient, which is related to the material's resistance to volumetric deformation. μ The second Lamé coefficient, also known as the shear modulus, is used to measure a material's ability to resist shear deformation. ρ The density of the material; v p For the speed of transmission.

6. A calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics, characterized in that, The calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics is used to implement the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics as described in any one of claims 1-5. The calibration-free stress measurement device based on ultrasonic longitudinal waves and incremental deformation mechanics includes: Longitudinal wave excitation sensor, longitudinal wave receiving sensor, and processing unit; The longitudinal wave excitation sensor is used to emit ultrasonic longitudinal waves as excitation signals at the detection point of the test piece under applied stress. The longitudinal wave receiving sensor is used to acquire the ultrasonic longitudinal wave time domain signal at the test point of the test specimen; The processing unit is used to determine the propagation time of the longitudinal wave in the test specimen based on the ultrasonic longitudinal wave time-domain signal; to determine the propagation speed of the ultrasonic longitudinal wave in the test specimen based on the thickness of the test specimen and the propagation time of the longitudinal wave in the test specimen; and to determine the stress value at the test point of the test specimen based on the propagation speed of the ultrasonic longitudinal wave in the test specimen.

7. A calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics, characterized in that, The calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics is used to implement the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics as described in any one of claims 1-5. The calibration-free stress measurement system based on ultrasonic longitudinal waves and incremental deformation mechanics includes: The data acquisition module is used to acquire the ultrasonic longitudinal wave time-domain signal and the thickness of the test specimen at the test point; The propagation time determination module is used to determine the propagation time of the longitudinal wave in the test specimen based on the ultrasonic longitudinal wave time domain signal. The propagation speed determination module is used to determine the propagation speed of the ultrasonic longitudinal wave in the test specimen based on the thickness of the test specimen and the propagation time. The stress value determination module is used to determine the stress value at the test point of the specimen under test based on the propagation speed.

8. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that the processor executes the computer program to implement the calibration-free stress measurement method based on ultrasonic longitudinal waves and incremental deformation mechanics as described in any one of claims 1-5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the calibration-free stress measurement method based on ultrasonic longitudinal wave and incremental deformation mechanics as described in any one of claims 1-5.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the calibration-free stress measurement method based on ultrasonic longitudinal wave and incremental deformation mechanics as described in any one of claims 1-5.

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