Method and device for calculating elastic constants of a plate-shaped composite material

Abstract

The application discloses a method and device for calculating elastic constants of a plate-shaped composite material. The method comprises the following steps: detecting M waveform data corresponding to ultrasonic Lamb waves of the plate-shaped composite material propagating at an i-th propagation angle in N propagation angles, and calculating i-th first dispersion data through the M waveform data; calculating i-th second dispersion data corresponding to the i-th propagation angle according to i-th first elastic constant data corresponding to the i-th propagation angle and characteristic information of the ultrasonic Lamb waves; taking a least square fitting difference of the i-th first dispersion data and the i-th second dispersion data on a target frequency band as i-th target function; solving the target function by taking the function value of minimizing the i-th target function as an optimization target, and obtaining i-th second elastic constant data, wherein the i-th second elastic constant data comprises optimization parameter values of at least two target elastic constants, so as to determine the multiple target elastic constants.

Description

Technical Field

[0001] This application relates to the field of ultrasonic nondestructive testing technology, specifically to a method and apparatus for calculating the elastic constants of plate-shaped composite materials. Background Technology

[0002] Fiber-reinforced composite materials can meet various lightweight and structural mechanics design requirements and are currently widely used in the aerospace industry. Fiber-reinforced composite materials typically exhibit significant anisotropy, and accurately obtaining their elastic constants is a prerequisite for better application.

[0003] While experimental testing equipment for elastic constant mechanics is mature, it requires the preparation of various standard specimens and the acquisition of the material's elastic constants through methods such as tension or bending. This method is costly and destructive to the test specimens. Current ultrasonic guided wave measurement methods rely on laser vibrometers for data acquisition, which are expensive and unsuitable for practical testing. Therefore, a simple and efficient scheme is needed to determine the elastic constants of composite materials. Summary of the Invention

[0004] This invention provides a method and apparatus for calculating the elastic constants of plate-shaped composite materials.

[0005] Firstly, a method for calculating the elastic constants of plate-shaped composite materials is provided, the method comprising:

[0006] For any i-th propagation angle among N predetermined propagation angles, detect M waveform data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle in the plate-shaped composite material, where N and M are both integers greater than 1;

[0007] Based on the M waveform data corresponding to the i-th propagation angle, calculate the i-th first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle;

[0008] Based on the first elastic constant data corresponding to the i-th propagation angle and the characteristic information of the ultrasonic Lamb wave propagating at the i-th propagation angle, the i-th second dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle is calculated; wherein, the first elastic constant data includes the assumed parameter values ​​of at least two target elastic constants corresponding to the i-th propagation angle.

[0009] The least squares fit difference between the i-th first dispersion data and the i-th second dispersion data in the target frequency band is taken as the i-th objective function;

[0010] The objective function is solved with minimizing the function value of the i-th objective function as the optimization objective, and the i-th second elastic constant data is obtained, wherein the i-th second elastic constant data includes the optimization parameter values ​​of each of the at least two objective elastic constants;

[0011] Based on the data of each of the second elastic constants, multiple target elastic constants are determined.

[0012] In one possible implementation, the M waveform data corresponding to the i-th propagation angle are processed based on the matrix constraint method to obtain the i-th first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle.

[0013] In one possible implementation, the target frequency band is obtained based on the data amplitude spectrum and signal-to-noise ratio.

[0014] In one possible implementation, the objective function is solved by optimizing the objective function to minimize the function value of the objective function, thereby obtaining the i-th second elastic constant data.

[0015] In one possible implementation, for any i-th propagation angle among N predetermined propagation angles,

[0016] Based on the P predetermined modes of the ultrasonic Lamb wave, the M waveform data corresponding to the i-th propagation angle are calculated, and the i-th first dispersion data corresponding to the p-th mode is used to calculate multiple target elastic constants in the p-th mode of the ultrasonic Lamb wave.

[0017] In one possible implementation, the number of at least two target elastic constants corresponding to the i-th propagation angle is not less than the number of at least two target elastic constants corresponding to the (i-1)-th propagation angle;

[0018] The step of solving the objective function with minimizing the function value of the i-th objective function as the optimization objective to obtain the i-th second elastic constant data includes: substituting the optimization parameter values ​​of at least two objective elastic constants corresponding to the (i-1)-th propagation angle into the i-th objective function to obtain the i-th intermediate function; and solving the objective function with minimizing the function value of the intermediate function as the optimization objective to obtain the i-th second elastic constant data.

[0019] In one possible implementation, for any two first elastic constant data corresponding to any two propagation angles, the two assumed parameter values ​​corresponding to the same elastic constant in the two first elastic constant data are the same.

[0020] Secondly, a device for calculating the elastic constants of a plate-shaped composite material is provided, the device comprising:

[0021] The ultrasonic acquisition unit is used to detect M waveform data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle in the plate-shaped composite material for any i-th propagation angle among N predetermined propagation angles, where N and M are both integers greater than 1.

[0022] The first calculation unit is used to calculate the first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle based on the M waveform data corresponding to the i-th propagation angle.

[0023] The second calculation unit is used to calculate the i-th second dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle based on the i-th first elastic constant data corresponding to the i-th propagation angle and the characteristic information of the ultrasonic Lamb wave propagating at the i-th propagation angle; wherein, the i-th first elastic constant data includes the assumed parameter values ​​of at least two target elastic constants corresponding to the i-th propagation angle.

[0024] The data optimization unit is used to take the least squares fitting difference between the i-th first dispersion data and the i-th second dispersion data in the target frequency band as the i-th objective function; and to solve the objective function with minimizing the function value of the i-th objective function as the optimization objective to obtain the i-th second elastic constant data, wherein the i-th second elastic constant data includes the optimization parameter values ​​of each of the at least two objective elastic constants;

[0025] The data determination unit is used to determine the plurality of target elastic constants based on each of the second elastic constant data.

[0026] Thirdly, a computing device is provided, including a memory and a processor, wherein the memory stores executable code, and the processor executes the executable code to implement the method described in any one of the first aspects above.

[0027] Fourthly, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method described in any one of the first aspects above.

[0028] In the technical solution provided in this application, first dispersion data is obtained from waveform data collected from plate-shaped composite materials, and second dispersion data of ultrasonic Lamb waves is calculated based on a pre-determined assumed value of the target elastic constant. The second dispersion data of ultrasonic Lamb waves is compared with the first dispersion data to seek the assumed value of the target elastic constant that makes the second dispersion data closest to the first dispersion data, i.e., the optimization parameter value. The optimization parameter value is then used as the target elastic constant, thereby realizing the non-destructive measurement of the elastic constant of plate-shaped composite materials. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of 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.

[0030] Figure 1 A flowchart illustrating a method for calculating the elastic constants of a plate-shaped composite material according to an embodiment of this application is shown.

[0031] Figure 2 This illustration shows one of the schematic diagrams of first and second dispersion data of a plate-shaped composite material provided in an embodiment of this application;

[0032] Figure 3 This is a second schematic diagram illustrating the first and second dispersion data of a plate-shaped composite material provided in an embodiment of this application.

[0033] Figure 4 This is shown as a third schematic diagram of first and second dispersion data of a plate-shaped composite material provided in an exemplary embodiment of this application;

[0034] Figure 5 A schematic diagram of the structure of a device for calculating the elastic constant of a plate-shaped composite material provided in an embodiment of this application is shown. Detailed Implementation

[0035] The solution provided in this specification will now be described with reference to the accompanying drawings.

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments in this specification, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without creative effort should fall within the scope of protection of this specification.

[0037] In the description of the embodiments of this application, the words "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the words "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a specific manner.

[0038] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. Furthermore, unless otherwise stated, the term "multiple" means two or more.

[0039] Furthermore, the terms "first" and "first" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the indicated technical feature. Thus, a feature defined with "first" or "first" may explicitly or implicitly include one or more of that feature. The terms "comprising," "including," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized.

[0040] Figure 1 This is a flowchart illustrating a method for calculating the elastic constants of a plate-shaped composite material, provided in an embodiment of this application. See also... Figure 1 As shown, the method may include, but is not limited to, some or all of the following steps S201 to S213.

[0041] S201, for any i-th propagation angle among N predetermined propagation angles, detect M waveform data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle in the plate composite material, where N and M are both integers greater than 1.

[0042] N ultrasonic receiving arrays can be arranged on the surface of a plate-like composite material according to N predetermined propagation angles. Each ultrasonic array includes one ultrasonic transmitter and M ultrasonic receivers. The propagation angle refers to the angle between the line connecting the ultrasonic transmitter and receiver and a reference line on the surface of the plate-like composite material. In the i-th ultrasonic array corresponding to the i-th propagation angle, the M ultrasonic receivers can be arranged at different positions on the same horizontal plane of the plate-like composite material, each receiving the ultrasonic Lamb wave signal emitted by the ultrasonic transmitter in the i-th ultrasonic array, thereby obtaining M waveform data.

[0043] Ultrasonic Lamb waves of the same frequency propagate at approximately the same speed at the same angle. However, due to the heterogeneity and anisotropy of materials, as well as the influence of contact conditions, the ultrasonic Lamb wave signals received at different locations may exhibit slight differences. These differences may manifest as variations in signal intensity, phase, amplitude, etc. Therefore, by arranging M ultrasonic receivers to process and analyze the ultrasonic Lamb wave signals at different locations, more accurate material property information can be obtained in subsequent processes, i.e., more accurate elastic constants can be obtained through subsequent processes.

[0044] S203, based on the M waveform data corresponding to the i-th propagation angle, calculate the i-th first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle.

[0045] The M waveform data corresponding to the i-th propagation angle are considered as a whole. Array signal processing technology is used to obtain a single overall waveform data corresponding to the i-th propagation angle. Specifically, at multiple locations on the plate-like composite material A corresponding to the i-th propagation angle, the single overall waveform data can represent the combined characteristics of the ultrasonic Lamb waveform data at multiple locations. Then, using signal processing technology, the i-th first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle is extracted from the obtained single overall waveform data. The first dispersion data describes the relationship between the velocity and frequency of the ultrasonic Lamb wave propagating in the plate-like composite material, which can be specifically expressed as the following formula 1:

[0046]

[0047] in, This represents the first dispersion data of the ultrasonic Lamb wave propagating along the i-th propagation angle, where θ represents the angle value of the i-th propagation angle; ω represents the angular frequency of the ultrasonic Lamb wave; and k represents the wavenumber of the ultrasonic Lamb wave.

[0048] For example, when testing a 5.16mm thick plate-shaped composite material AA, ten waveform data points are obtained at three propagation angles: along the principal axis of the composite material AA, at a 45° angle to the principal axis, and at a 90° angle to the principal axis. Preprocessing and waveform superposition are then performed to remove potential noise, filter, and calibrate the data. The ten waveform data points for each propagation angle are then converted into a single overall waveform. Next, a Fourier transform is performed on the overall waveform to convert the time-domain signal into a frequency-domain signal, thus obtaining the frequency spectrum of the overall waveform. Then, by calculating the phase changes of different frequency components in the frequency domain waveform spectrum and their derivative relationships with frequency, the following parameters are obtained: Figure 2 , Figure 3 and Figure 4 The scatter plots represent the first and second dispersion data of the ultrasonic Lamb wave under three propagation angles.

[0049] In one possible implementation, based on the matrix constraint method, the M waveform data corresponding to the i-th propagation angle are processed to obtain the i-th first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle.

[0050] The M waveform data corresponding to the i-th propagation angle are sorted to form an M-row data matrix, where each row corresponds to the waveform data of a receiver. Then, singular value decomposition, model order determination, and pseudospectral construction are performed on the M-row data matrix to obtain the frequency spectrum corresponding to the i-th propagation angle, and the first dispersion data is extracted from it.

[0051] S205, based on the first elastic constant data corresponding to the i-th propagation angle and the characteristic information of the ultrasonic Lamb wave propagating at the i-th propagation angle, calculate the i-th second dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle; wherein, the i-th first elastic constant data includes the assumed parameter values ​​of at least two target elastic constants corresponding to the i-th propagation angle.

[0052] First, based on the empirical values ​​of the target elastic constants for each material type included in the known plate-shaped composite material, the range of assumed parameter values ​​corresponding to the target elastic constant is obtained. Then, assumed parameter values ​​are randomly selected within this range to determine the i-th first elastic constant data based on the assumed parameter values ​​of the target elastic constant. The first elastic constant data, i.e., the first elastic data, includes the assumed parameter values ​​for at least two elastic parameters corresponding to the i-th propagation angle, where the at least two elastic parameters belong to a predetermined set of target elastic parameters.

[0053] Through theoretical analysis of the ultrasonic propagation characteristics of plate-shaped composite materials, the dispersion equation of the ultrasonic Lamb wave propagating at the i-th propagation angle can be obtained based on the wave number, propagation angle, and other characteristic information of the ultrasonic Lamb wave propagating at the i-th propagation angle, and the i-th first elastic constant data corresponding to the i-th propagation angle. For example, the dispersion equation of the ultrasonic Lamb wave can be obtained according to the following formula 2:

[0054] D(θ,k,ω,h,C)=0 (2)

[0055] Where θ represents the angle value of the i-th propagation angle; ω represents the angular frequency of the ultrasonic Lamb wave; k represents the wavenumber of the ultrasonic Lamb wave; h is the thickness of the plate-shaped composite material; and C represents the data of the i-th first elastic constant corresponding to the i-th propagation angle.

[0056] Subsequently, using Newton's iteration or the bisection method, the roots of the dispersion equation are solved frequency by frequency to obtain the second dispersion data of the ultrasonic Lamb wave propagating along the i-th propagation angle. The second dispersion data is specifically represented by the following formula 3:

[0057]

[0058] This represents the first dispersion data of the ultrasonic Lamb wave propagating along the i-th propagation angle, where θ represents the angle value beyond the i-th propagation angle; ω represents the angular frequency of the ultrasonic Lamb wave; and k represents the wavenumber of the ultrasonic Lamb wave.

[0059] S207: Obtain the target frequency band based on the data amplitude spectrum and signal-to-noise ratio.

[0060] Based on the amplitude of different frequency bands in the amplitude spectrum of the ultrasonic Lamb wave, target frequency bands with significant amplitude of the ultrasonic Lamb wave are obtained; at the same time, target frequency bands with low signal-to-noise ratio are eliminated from the target frequency bands with significant amplitude to ensure that the signal in the selected target frequency band can be effectively extracted.

[0061] S209, take the least squares fitting difference between the i-th first dispersion data and the i-th second dispersion data in the target frequency band as the i-th objective function.

[0062] For example, the least squares fitting difference between the i-th first dispersion data and the i-th second dispersion data in the target frequency band can be calculated using the following formula 4:

[0063]

[0064] Where E represents the least squares fitting difference between the i-th first dispersion data and the i-th second dispersion data; This represents the second dispersion data of the ultrasonic Lamb wave propagating along the i-th propagation angle; Ω represents the target frequency band; This represents the first dispersion data of the ultrasonic Lamb wave propagating along the i-th propagation angle.

[0065] S211, with minimizing the function value of the i-th objective function as the optimization objective, solve the objective function to obtain the i-th second elastic constant data, wherein the i-th second elastic constant data includes the optimization parameter values ​​of at least two objective elastic constants.

[0066] The objective function is solved by minimizing the value of the i-th objective function. In other words, it is to find the minimum value of the least squares fitting difference between the i-th dispersed data and the i-th second dispersed data. Simultaneously, the first elasticity constant data of the i-th second dispersed data corresponding to the objective function is used as the i-th second elasticity constant data. The second elasticity constant data, i.e., the second elastic data, includes the optimization parameter values ​​of at least two elastic parameters. Methods for solving the objective function include predator-prey genetic algorithms, particle swarm optimization, etc.

[0067] In one possible implementation, an adaptive predator-prey genetic algorithm is used to solve the objective function with the goal of minimizing the function value of the objective function, thereby obtaining the i-th second elastic constant data.

[0068] The adaptive predator-prey genetic algorithm is a global optimization algorithm that simulates natural evolution and genetic theory. By transferring the optimization problem, it successfully avoids the need to consider too much dynamic information, which is common in general optimization algorithms. In the predator-prey genetic algorithm, the population represents the feasible solution domain of the objective function; individuals in the population represent each feasible solution of the objective function within the feasible solution domain; each individual contains two chromosomes, which encode each feasible solution; each chromosome contains a set of genes, and each set of genes contains multiple gene segments. Common encoding methods include binary encoding and floating-point encoding.

[0069] For example, the objective function can be solved using the following steps:

[0070] Chromosome encoding is performed based on the range of the assumed elasticity constant; the population is initialized by setting parameters such as the number of individuals N, chromosome length, and generation M, and n individuals are randomized.

[0071] The objective function values ​​of n individuals in the m-th generation population are calculated using the function, and these values ​​are used as the fitness of the n individuals. The optimal fitness and the current generation optimal fitness are then obtained.

[0072] Obtain the ratio g of the optimal fitness to the current best fitness, and obtain the comparison value k. When the ratio g > the comparison value k, a local search strategy is adopted; when the comparison value k ≥ the ratio g, a global search strategy is adopted.

[0073] Based on the fitness value, x individuals are selected from n individuals; where x < n when using a global search strategy, and x = n when using a local search strategy.

[0074] Based on the search strategy employed by the predator-prey genetic algorithm, a crossover point is randomly set on each chromosome of the acquired x individuals. At this point, gene segments from two paired individuals are exchanged, resulting in x crossover individuals. Subsequently, a crossover point is randomly set on each chromosome of the x crossover individuals, and mutation operations are performed on one or more gene segments at that point, resulting in x mutated individuals. Different search strategies affect the range of gene mutations on the chromosomes of each individual in the population.

[0075] Combine x mutant individuals with nx individuals to form the (m+1)th generation population. Calculate the fitness of each individual in the population and obtain the optimal fitness and the current generation's optimal fitness.

[0076] When the number of generations reaches a set value M, the individual with the optimal fitness value in the population of generation M is taken as the target solution.

[0077] In one possible implementation, the optimization parameter values ​​of at least two target elastic constants corresponding to the (i-1)th propagation angle are substituted into the i-th objective function to obtain the i-th intermediate function; the objective function is solved with minimizing the function value of the intermediate function as the optimization objective to obtain the i-th second elastic constant data.

[0078] For example, when calculating the elastic constants of a 5.16mm thick plate-shaped composite material A, the first dispersion data of the ultrasonic Lamb wave is pre-determined at three propagation angles: along the principal axis of the plate-shaped composite material A (i.e., at an angle of 0° to the principal axis), at an angle of 90° to the principal axis, and at an angle of 45° to the principal axis. Based on the first first dispersion data and the first first elastic constant data of the ultrasonic Lamb wave propagating along the principal axis at the first propagation angle, the first second elastic constant data is calculated. The first second elastic constant data includes c. 11 c 33 c 13 c 55 Four optimization parameter values; the second dispersion data fitted based on these four optimization parameter values ​​obtained at the propagation angle along the principal axis direction is as follows: Figure 2 As shown by the solid line in the middle.

[0079] Subsequently, when calculating the second second elastic constant data based on the second propagation angle (i.e., the ultrasonic Lamb wave at a propagation angle of 90° to the principal axis direction), the calculated c... 33 The optimization parameter values ​​are used as known parameters and substituted into the second objective function corresponding to the second propagation angle to obtain an intermediate function. The objective function is solved by minimizing the function value of the intermediate function to obtain the second elastic constant data. The second elastic constant data includes c. 22 c 23 c 44 The optimal parameter values; the theoretical dispersion data fitted based on these three optimal parameter values ​​obtained at a propagation angle of 90° with the principal axis, as shown in the figure. Figure 3 As shown by the solid line in the middle.

[0080] Finally, when calculating the third second elastic constant data based on the third propagation angle (i.e., the ultrasonic Lamb wave at a propagation angle of 45° with the principal axis), the calculated c... 11 c 33 c 13 c 55 c 22 c 23 c 44Seven optimization parameter values ​​are used as known parameters. These are substituted into the third objective function corresponding to the third propagation angle to obtain an intermediate function. The objective function is then solved by minimizing the value of this intermediate function to obtain the third second elastic constant data. This third second elastic constant data includes c. 12 and c 66 The optimal parameter values; the theoretical dispersion data fitted based on the three optimal parameter values ​​obtained at a propagation angle of 45° with the principal axis, as shown in the figure. Figure 4 As shown by the solid line in the middle.

[0081] In the example above, the optimization parameter values ​​of at least two target elastic constants corresponding to the (i-1)th propagation angle are the optimization parameter values ​​of at least two elastic parameters corresponding to the (i-1)th elastic parameter.

[0082] In one possible implementation, for any two first elastic constant data corresponding to any two propagation angles, the two assumed parameter values ​​corresponding to the same elastic constant in the two first elastic constant data are the same.

[0083] S213, Based on the data of each second elastic constant, determine multiple target elastic constants.

[0084] The optimization parameter values ​​of multiple elastic constants contained in the N second elastic constant data are taken as their respective target elastic constants; that is, the elastic constants of multiple target elastic parameters are determined based on each second elastic data. In other words, the target elastic constant can be the optimization parameter value of its corresponding elastic parameter, or the average value of the optimization parameter values ​​of the corresponding elastic parameter obtained from multiple measurements.

[0085] Nine target elastic parameters / target elastic constants c of plate-shaped composite material A 11 c 13 c 33 c 55 c 22 c 23 c 44 c 12 c 66 The calculations were performed, and the results are shown in Table 1 below. The two elastic constants c of the composite material were obtained using ultrasonic volume wave measurement. 11 and c 22 The measurement results are the true values ​​in Table 1. Then, the elastic constant c was calculated. 11 and c 22 The error between the two values ​​and the corresponding true values ​​is -3.14%, which demonstrates the accuracy of the elastic constant calculation method provided in this application.

[0086] Table 1

[0087] <![CDATA[c 11 ]]> 77.95 75.5 <![CDATA[c 13 ]]> / 10.0 <![CDATA[c 33 ]]> / 13.4 <![CDATA[c 55 ]]> / 3.2 <![CDATA[c 22 ]]> 77.95 75.5 <![CDATA[c 23 ]]> / 10.3 <![CDATA[c 44 ]]> / 3.3 <![CDATA[c 12 ]]> / 15.3 <![CDATA[c 66 ]]> / 4.5

[0088] In one possible implementation, based on P predetermined modes of the ultrasonic Lamb wave, the first dispersion data corresponding to the i-th waveform data corresponding to the i-th propagation angle in the p-th mode is calculated using the data to calculate multiple target elastic constants in the p-th mode of the ultrasonic Lamb wave.

[0089] Ultrasonic Lamb waves exist in various modes, such as symmetrical modes S0, S1, S2, etc., and antisymmetric modes A0, A1, A2, etc. For the same plate-shaped composite material, the waveform data of the ultrasonic Lamb waves obtained along the i-th propagation angle are not the same for different modes, but the optimization parameter values ​​of the obtained second elastic constant data are still the same. Therefore, the optimization values ​​of the second elastic constant data obtained by the M waveform data corresponding to the p-th mode at the i-th propagation angle and the optimization values ​​of the second elastic constant data obtained by subsequent operations can be used to verify the optimization values ​​of the second elastic constant data obtained by the other P-1 modes at the i-th propagation angle.

[0090] In this study, the plate-shaped composite material AA was tested at a propagation angle of 0°. After obtaining 10 waveform data of the ultrasonic Lamb wave, the matrix beam method was used to extract the waveforms as follows: Figure 2 The first dispersion data of the four ultrasonic Lamb wave modes A0, S0, A1 and A2 are shown.

[0091] Corresponding to the method provided in this application, Figure 5 The diagram shows the structure of a device 400 for calculating the elastic constants of a plate-shaped composite material provided in this application. See also... Figure 5 As shown, the device includes: an ultrasound acquisition unit 401, a first calculation unit 403, a second calculation unit 405, a data optimization unit 407, and a data determination unit 409.

[0092] The ultrasonic acquisition unit 401 is used to detect M waveform data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle in the plate composite material for any i-th propagation angle among N predetermined propagation angles, where N and M are both integers greater than 1.

[0093] The first calculation unit 403 is used to calculate the first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle based on the M waveform data corresponding to the i-th propagation angle.

[0094] The second calculation unit 405 is used to calculate the i-th second dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle based on the i-th first elastic constant data corresponding to the i-th propagation angle and the characteristic information of the ultrasonic Lamb wave propagating at the i-th propagation angle; wherein, the i-th first elastic constant data includes the assumed parameter values ​​of at least two target elastic constants corresponding to the i-th propagation angle.

[0095] The data optimization unit 407 is used to take the least squares fitting difference between the i-th first dispersion data and the i-th second dispersion data in the target frequency band as the i-th objective function; and to solve the objective function with minimizing the function value of the i-th objective function as the optimization objective to obtain the i-th second elastic constant data, wherein the i-th second elastic constant data includes the optimization parameter values ​​of at least two objective elastic constants respectively.

[0096] The data determination unit 409 is used to determine the elastic constants of multiple target elastic constants based on N second elastic constant data.

[0097] According to another embodiment, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed in a computer, causes the computer to perform a combination Figure 1 The method described is executed by the ultrasound acquisition unit 401, the first calculation unit 403, the second calculation unit 405, the data optimization unit 407, and the data determination unit 409.

[0098] According to another embodiment, a computing device is also provided, including a memory and a processor, wherein executable code is stored in the memory, and when the processor executes the executable code, it implements a combination... Figure 1 The method described is executed by the ultrasound acquisition unit 401, the first calculation unit 403, the second calculation unit 405, the data optimization unit 407, and the data determination unit 409.

[0099] Those skilled in the art will recognize that, in one or more of the examples above, the functions described in this invention can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium.

[0100] The above specific embodiments further illustrate the purpose, technical solution and beneficial effects of this application. It should be understood that the above are only specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of this application should be included within the scope of protection of this application.

Claims

1. A method for calculating elastic constants of a plate-like composite material, comprising: detecting M waveform data corresponding to ultrasonic Lamb waves propagating at an i th propagation angle among predetermined N propagation angles, wherein N and M are integers greater than 1; calculating i th first dispersion data corresponding to the ultrasonic Lamb waves propagating at the i th propagation angle according to the M waveform data corresponding to the i th propagation angle; calculating i th second dispersion data corresponding to the ultrasonic Lamb waves propagating at the i th propagation angle according to i th first elastic constant data corresponding to the i th propagation angle and characteristic information of the ultrasonic Lamb waves propagating at the i th propagation angle, wherein the i th first elastic constant data comprises assumed parameter values of at least two target elastic constants corresponding to the i th propagation angle; taking a least square fitting difference between the i th first dispersion data and the i th second dispersion data in a target frequency band as an i th objective function; solving the objective function with a function value of the i th objective function minimized as an optimization target to obtain i th second elastic constant data, wherein the i th second elastic constant data comprises optimized parameter values of the at least two target elastic constants; determining a plurality of target elastic constants according to each of the second elastic constant data; the number of the at least two target elastic constants corresponding to the i th propagation angle is not less than the number of the at least two target elastic constants corresponding to an i-1 th propagation angle; the solving the objective function with the function value of the i th objective function minimized as the optimization target to obtain the i th second elastic constant data comprises: substituting optimized parameter values of the at least two target elastic constants corresponding to the i-1 th propagation angle into the i th objective function to obtain an i th intermediate function; and solving the objective function with a function value of the intermediate function minimized as the optimization target to obtain the i th second elastic constant data; processing the M waveform data corresponding to the i th propagation angle based on a matrix constraint method to obtain the i th first dispersion data corresponding to the ultrasonic Lamb waves propagating at the i th propagation; and obtaining the target frequency band according to a data amplitude spectrum and a signal-to-noise ratio. 4.The method of claim 3, wherein the solving the objective function with the function value of the i th objective function minimized as the optimization to obtain the i th second elastic constant data comprises: solving the objective function with the function value of the i th objective function minimized as the optimization target based on an adaptive predator-prey genetic algorithm to obtain the i th second elastic constant data. The calculating the i th first dispersion data corresponding to the ultrasonic Lamb waves propagating at the i th angle according to the M waveform data corresponding to the i th propagation angle comprises: ​ ​ ​ ​ ​ ​ 2. The method of claim 1, wherein calculating, according to the M waveform data corresponding to the i-th propagation angle, i-th first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle comprises: ​ 3. The method of claim 1, further comprising: ​ ​ ​ 5. The method provided in claim 1, wherein, ​ According to the P modes of the ultrasonic Lamb wave, the i-th first dispersion data corresponding to the M waveform data corresponding to the p-th mode is calculated, which is used for calculating a plurality of target elastic constants in the p-th mode of the ultrasonic Lamb wave.

6. The method of claim 1, wherein for any two first elastic constant data corresponding to any two propagation angles, two assumed parameter values corresponding to the same elastic constant in the two first elastic constant data are the same.

7. A device for calculating the elastic constants of a plate-shaped composite material, characterized in that, Comprise: An ultrasonic acquisition unit configured to detect, for any i-th propagation angle of N predetermined propagation angles, M waveform data corresponding to an ultrasonic Lamb wave propagating at the i-th propagation angle in the plate-shaped composite material, wherein N and M are both integers greater than 1; A first calculation unit configured to calculate, according to the M waveform data corresponding to the i-th propagation angle, i-th first dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle; A second calculation unit configured to calculate, according to i-th first elastic constant data corresponding to the i-th propagation angle and characteristic information of the ultrasonic Lamb wave propagating at the i-th propagation angle, i-th second dispersion data corresponding to the ultrasonic Lamb wave propagating at the i-th propagation angle; wherein the i-th first elastic constant data comprises assumed parameter values of at least two target elastic constants corresponding to the i-th propagation angle; A data optimization unit configured to take a least square fitting difference between the i-th first dispersion data and the i-th second dispersion data on a target frequency band as an i-th target function, and solve the target function with a function value of the i-th target function minimized as an optimization target to obtain i-th second elastic constant data, wherein the i-th second elastic constant data comprises optimization parameter values of the at least two target elastic constants; a number of the at least two target elastic constants corresponding to the i-th propagation angle is not less than a number of the at least two target elastic constants corresponding to an i-1-th propagation angle; The solving of the target function with the function value of the i-th target function minimized as the optimization target to obtain the i-th second elastic constant data comprises: substituting optimization parameter values of the at least two target elastic constants corresponding to the i-1-th propagation angle into the i-th target function to obtain an i-th intermediate function; and solving the target function with a function value of the intermediate function minimized as the optimization target to obtain the i-th second elastic constant data; A data determination unit configured to determine a plurality of target elastic constants according to each of the second elastic constant data.

8. A computing device comprising a memory and a processor, wherein the memory stores executable code, and the processor executes the executable code to implement the method of any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed in a computer, the computer program causes the computer to execute the method of any one of claims 1-6.

Images