Ultrasonic nondestructive characterization method and system for rigidity of automatic tape laying composite material

Abstract

The invention provides an ultrasonic lossless characterization method and system for rigidity of an automatic tape laying composite material, and relates to the technical field of materials.The ultrasonic lossless characterization method comprises the steps that ultrasonic excitation signals are emitted along at least two incident planes of a to-be-tested piece at at least two incident angles, and ultrasonic transmission data are obtained; and according to the ultrasonic excitation signal, the ultrasonic transmission data and the material related parameters, calculating to obtain a rigidity parameter of the to-be-tested piece. According to the method provided by the invention, the ultrasonic multi-plane multi-angle transmission data is adopted as the calculation data, and the rigidity information of the to-be-tested piece in each direction can be obtained, so that the lossless quantitative characterization of the anisotropic rigidity parameters of the composite material is realized.

Description

Technical Field

[0001] The present disclosure relates to the field of material technology, and particularly to an ultrasonic non-destructive characterization method and system for the stiffness of automatic tape laying composites. Background Art

[0002] Due to the advantages of high specific strength, high specific stiffness, fatigue resistance, and designability, composites have been widely used in the aerospace field. During operation, major composite equipment needs to withstand extreme temperature, pressure, and mechanical loads. Therefore, accurate stiffness performance characterization is crucial for ensuring that the material and structure designs meet the established strength and stiffness requirements, which is directly related to the integrity and safety of the equipment. In addition, accurate stiffness performance data can also provide necessary data support for lightweight design and structural performance optimization.

[0003] However, for automatic tape laying composites, different material systems and processing parameters result in complex and variable internal structures, with differences in fiber volume ratio, porosity, and interface conditions, which in turn lead to a large dispersion in the stiffness coefficients of the composites. Therefore, it is of great significance to detect the stiffness parameters of composites both in design verification and in the application level. Summary of the Invention

[0004] To solve the above technical problems, the present disclosure provides an ultrasonic non-destructive characterization method and system for the stiffness of automatic tape laying composites.

[0005] On the one hand, the present disclosure provides an ultrasonic non-destructive characterization method for the stiffness of automatic tape laying composites, including: emitting ultrasonic excitation signals at at least two incident angles along at least two incident planes of a test piece to obtain ultrasonic transmission data, wherein the test piece is made by an automatic tape laying process;

[0006] Calculating the stiffness parameters of the test piece according to the ultrasonic excitation signals, the ultrasonic transmission data, and material-related parameters; wherein the material-related parameters at least include the thickness and density of the test piece.

[0007] On the other hand, based on the same inventive concept, the present disclosure also provides an ultrasonic non-destructive characterization system for the stiffness of automatic tape laying composites, including:

[0008] An ultrasonic detection module for emitting ultrasonic excitation signals at at least two incident angles along at least two incident planes of a test piece to obtain ultrasonic transmission data, wherein the test piece is made by an automatic tape laying process;

[0009] A stiffness calculation module for calculating the stiffness parameters of the test piece according to the ultrasonic excitation signals, the ultrasonic transmission data, and material-related parameters.

[0010] The technical solution provided by the present disclosure has the following advantages compared with the prior art:

[0011] The present disclosure provides an ultrasonic non-destructive characterization method and system for the stiffness of automatic tape-laying composites. By using ultrasonic multi-plane and multi-angle transmission data as calculation data, the stiffness information of the test piece in each direction can be obtained, and thus the non-destructive quantitative characterization of the anisotropic stiffness parameters along the composite material can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present disclosure and used together with the specification to explain the principles of the present disclosure.

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0014] Figure 1 It is a schematic flow chart of an ultrasonic non-destructive characterization method for the stiffness of automatic tape-laying composites provided by an embodiment of the present disclosure;

[0015] Figure 2 It is a schematic diagram of a detection scenario of an ultrasonic non-destructive characterization method for the stiffness of automatic tape-laying composites provided by an embodiment of the present disclosure;

[0016] Figure 3 It is a schematic diagram of modules of an ultrasonic non-destructive characterization system for the stiffness of automatic tape-laying composites provided by an embodiment of the present disclosure;

[0017] Figure 4 It is a schematic structural diagram of an ultrasonic transmission test platform provided by an embodiment of the present disclosure;

[0018] Figure 5 It is a time-domain diagram of an ultrasonic excitation signal provided by an embodiment of the present disclosure;

[0019] Figure 6 It is a frequency-domain diagram of an ultrasonic excitation signal provided by an embodiment of the present disclosure;

[0020] Figure 7 It is a stiffness matrix diagram provided by an embodiment of the present disclosure;

[0021] Figure 8 It is another stiffness matrix diagram provided by an embodiment of the present disclosure;

[0022] Figure 9 It is yet another stiffness matrix diagram provided by an embodiment of the present disclosure;

[0023] Figure 10 Another stiffness matrix diagram provided by the embodiments of the present disclosure;

[0024] Figure 11 Another stiffness matrix diagram provided by the embodiments of the present disclosure;

[0025] Figure 12 Another stiffness matrix diagram provided by the embodiments of the present disclosure;

[0026] Figure 13 A schematic diagram of the hardware structure of an electronic device provided by the embodiments of the present disclosure. Specific embodiments

[0027] In order to more clearly understand the above objects, features and advantages of the embodiments of the present disclosure, the solutions of the embodiments of the present disclosure will be further described below. It should be noted that, without conflict, the embodiments of the present disclosure and the features in the embodiments may be combined with each other.

[0028] Many specific details are set forth in the following description in order to provide a thorough understanding of the embodiments of the present disclosure, but the embodiments of the present disclosure may be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present disclosure, rather than all of the embodiments.

[0029] A composite laminate is a composite material plate formed by laminating and pressing two or more layers of the same or different materials. Common composite materials such as carbon fiber reinforced composites, glass fiber reinforced composites, etc., with their good mechanical properties, excellent fatigue resistance and other excellent characteristics, are more and more widely used in the fields of aerospace, military and so on.

[0030] Composites are different from isotropic materials and generally have anisotropy. Anisotropy means that generally, the mechanical properties of materials are different along different directions. Isotropic materials have an infinite number of material property symmetry planes, and their mechanical properties are the same along any direction, and their stiffness properties can be fully characterized by two independent parameters. Composites can be mainly divided into three types: transversely isotropic, orthotropic and fully isotropic according to the number of symmetry planes.

[0031] The related art detects the stiffness parameters of composites through the following methods:

[0032] Traditional quasi-static mechanical testing methods: Usually, the material to be tested needs to be cut and prepared into specimens with multiple fiber directions that meet the mechanical testing standards. Equipment such as an electronic universal material testing machine is used to conduct uniaxial tensile tests, three-point bending tests, pure torsion tests, and shear tests, etc. The mechanical property parameters such as the macroscopic tensile, bending, torsion, and shear moduli of the specimen to be tested can be obtained. It is the most commonly used destructive testing method. However, destructive tests often require the preparation of multiple identical test specimens, and multiple experimental tests are carried out to reduce accidental errors. The testing process is difficult, complex, and time-consuming, and the experimental cost is high.

[0033] Nanoindentation technology: Usually, the load on the indenter is continuously changed through nanoindentation control, and the indentation depth is measured in real time. Since an ultra-low load is applied and the monitoring sensor has a displacement resolution better than 1 nm, it is possible to achieve an indentation depth as small as the nanoscale (0.1 - 100 nm). It is suitable for measuring the mechanical properties of ultra-thin layer materials such as thin films and coatings, and can measure the mechanical properties of materials at the nanoscale, such as hardness, elastic modulus, fracture toughness, viscoelasticity, or creep behavior, etc. However, nanoindentation technology measures the elastic modulus of materials at the nanoscale (1 - 100 nm). This kind of micro-mechanical property reflects the behavior of materials at a very small scale and is greatly affected by the pore distribution, and there is often a certain deviation from the macroscopic mechanical properties of materials.

[0034] Traditional dynamic resonance testing: The free beam resonance method and the pulse excitation method are used to apply a dynamic load in the form of periodic tensile, compressive, or bending to the specimen of the material to be tested, analyze its dynamic response to obtain its resonance frequency, and then calculate the Young's modulus and shear modulus of the specimen to be tested. However, the testing accuracy of traditional dynamic resonance testing is greatly affected by the position of the specimen support points and the parallelism of the upper and lower surfaces of the strip-shaped specimen to be tested.

[0035] Ultrasonic resonance spectroscopy method: Usually, the material to be tested needs to be prepared into a regular-shaped cuboid, cylinder, or sphere. The two vertices of the specimen to be tested are gently clamped between two piezoelectric transducers. The ultrasonic wave excites the specimen to generate free vibration, and the response of the specimen is sensed by the receiving transducer to obtain a resonance spectrum containing multiple natural frequencies of the specimen. Then, combined with the mathematical inversion method, the anisotropic stiffness coefficients of the material are obtained. The ultrasonic resonance spectroscopy method can measure the anisotropic stiffness coefficients. However, in the process of estimating the material stiffness coefficients based on the ultrasonic resonance spectroscopy method, the calculation of the theoretical resonance frequency of the specimen is a key link. Generally, the Rayleigh-Ritz method is used to achieve it, and volume integration of the specimen is required. The specimen is required to be a regular-shaped cuboid, cylinder, or sphere, and the accurate measurement of the stiffness coefficients has high requirements for the shape accuracy of the test specimen. However, due to factors such as size, physical, or chemical properties, it is very difficult to be processed into a specimen with a regular shape required by the ultrasonic resonance spectroscopy method. At this time, if a specimen that does not meet the requirements is regarded as a regular body for calculation, it will have a great impact on the estimated results of the stiffness coefficients.

[0036] In view of this, the present disclosure provides a method and system for ultrasonic non-destructive characterization of the stiffness of automated fiber placement composites.

[0037] Figure 1 Please refer to the flowchart of a method for ultrasonic non-destructive characterization of the stiffness of automated fiber placement composites provided by an embodiment of the present disclosure. Figure 1 The ultrasonic non-destructive characterization method of the stiffness of automated fiber placement composites includes:

[0038] S1. Transmit ultrasonic excitation signals at at least two incident angles along at least two incident planes of the test piece to obtain ultrasonic transmission data. The test piece is made by the automated fiber placement process. Optionally, the test piece is made of anisotropic materials, which can be orthotropic or fully isotropic materials. Specifically, transmitting an ultrasonic excitation signal along a certain incident plane of the test piece means that the incident paths of the ultrasonic excitation signals are all within the incident plane. The same applies to other embodiments of the present disclosure and will not be elaborated further. It should be noted that the automated fiber placement process (AFP) is an advanced composite manufacturing technology, mainly used for efficiently and precisely laying fiber-reinforced prepregs (such as carbon fiber, glass fiber, etc.) to manufacture large composite structural parts with complex shapes.

[0039] S2. Calculate the stiffness parameters of the test piece based on the ultrasonic excitation signals, the ultrasonic transmission data measured through multi-plane and multi-angle in step S1, and material-related parameters, where the material-related parameters at least include the thickness and density of the test piece.

[0040] Ultrasonic signals can perform non-destructive detection on the defects, geometric characteristics, tissue structure, and mechanical property changes of the test piece. Compared with traditional mechanical testing methods, ultrasonic waves have the characteristics of strong penetration ability, sensitivity to the microscopic structure of materials, and the ability to carry a large amount of wave information, and the detection cost is low.

[0041] Specifically, the ultrasonic waves (i.e., the above-mentioned ultrasonic excitation signals) propagate inside the test piece and satisfy the equilibrium equation, geometric equation, and constitutive equation of the material. Based on this, the Christoffel equation satisfied by the propagation of ultrasonic waves in anisotropic media can be deduced. This equation describes the theoretical relationship between the stiffness parameters of the material and the phase velocity and attenuation velocity of ultrasonic wave propagation in the material. Therefore, the ultrasonic transmission data is directly related to the stiffness parameters of the material and carries all the information required to calculate the stiffness parameters.

[0042] The method provided by the embodiment of the present disclosure uses ultrasonic multi-plane and multi-angle transmission data as calculation data, and can obtain the stiffness information of the test piece in each direction, thereby realizing the non-destructive quantitative characterization of the anisotropic stiffness parameters of the composite material, which is beneficial to realizing the non-destructive detection of the composite material.

[0043] Specifically, Figure 2 Please refer to the schematic diagram of the detection scenario of an ultrasonic non-destructive characterization method for the stiffness of an automatically laid tape composite material provided by this embodiment of the disclosure. Figure 2 , taking the test piece 100 as a flat piece as an example, a rectangular coordinate system is usually used to describe different directions of the material, and the coordinate axes can be labeled as 1, 2, 3, and Specifically, the coordinate axis 1 can be the normal direction of the ultrasonic incident surface of the test piece, the coordinate axis 2 can be the in-plane fiber direction of the ultrasonic incident surface of the test piece, the coordinate axis 3 can be the in-plane direction perpendicular to the fiber of the ultrasonic incident surface of the test piece, and the coordinate axis is at a 45° angle to the coordinate axis 2. These coordinate axes intersect, representing three main directions and a relative rotation direction respectively. In a specific embodiment, the stiffness of different regions 101 of the test piece 100 is also detected respectively. Specifically, as Figure 2 shown, the above ultrasonic excitation signal is emitted by an ultrasonic transducer. The ultrasonic transducer includes an excitation transducer 201 for emitting the ultrasonic excitation signal and a receiving transducer 202 for receiving ultrasonic transmission data. The excitation transducer and the receiving transducer are located on both sides of the test piece respectively. When performing the above method, the excitation transducer and the receiving transducer rotate relative to the test piece to change the incident angle of the ultrasonic excitation signal, and cooperate with the position of the test piece to perform the excitation and reception of the ultrasonic signal.

[0044] Please refer to Figure 1 and Figure 2 , an alternative implementation provided by this disclosure is that the above S1 includes emitting ultrasonic excitation signals at at least two incident angles θ along the P(1, 2) plane, P(1, 3) plane, and plane of the test piece. Figure 2 (a) shows the main axis direction of the composite material plate, Figure 2 (b) shows the multi-angle detection of the P(1, 3) plane, Figure 2 (c) shows the multi-angle detection of the P(1, 2) plane, Figure 2 (d) shows the multi-angle detection of the plane. It should be noted that the P(1, 2) plane refers to the incident plane defined by the coordinate axis 1 and the coordinate axis 2, and the same applies to other incident planes. The coordinate axis 1 can be the normal direction of the ultrasonic incident surface of the test piece, the coordinate axis 2 can be the in-plane fiber direction of the ultrasonic incident surface of the test piece, and the coordinate axis 3 can be the in-plane direction perpendicular to the fiber of the ultrasonic incident surface of the test piece.

[0045] In some embodiments, the above stiffness parameter includes a stiffness matrix, and the above S2 specifically includes:

[0046] The stiffness matrix of the component to be measured is calculated based on the ultrasonic excitation signal, ultrasonic transmission data, and material-related parameters. The stiffness matrix is used to describe the deformation behavior of a structural or material system under the action of forces, and can relate the external forces to the corresponding displacements, reflecting the overall rigidity characteristics of the system. Among them, the methods for calculating the stiffness matrix of the component to be measured include: obtaining the stiffness matrix that minimizes the objective function through an inversion algorithm, and the objective function is:

[0047]

[0048] where f represents the selected frequency, θ represents the ultrasonic oblique incidence angle, C ij represents the stiffness coefficient to be optimized, represents the theoretically calculated transmission sound field, represents the experimentally obtained transmission sound field. During specific calculations, the stiffness coefficient is continuously optimized through an inversion algorithm to minimize the deviation between the theoretically calculated transmission sound field and the experimentally obtained transmission sound field (for example, measured by the least squares method), that is, to minimize the corresponding F(C ij ). At this time, the corresponding stiffness coefficient is the characterized stiffness coefficient of the additive composite material.

[0049] During specific implementation, the above S2 further includes calculating the tensile modulus of the component to be measured according to the stiffness matrix. The tensile modulus, also known as Young's Modulus, is a measure of the ability of a material to resist deformation under uniaxial tension, reflecting the degree of elastic deformation of the material under the action of external forces, that is, the proportional relationship between stress and strain.

[0050] Anisotropic materials usually have multiple orthogonal elastic symmetry planes, as well as elastic principal directions perpendicular to the symmetry plane directions, and have multiple independent stiffness coefficients. In multiple elastic principal directions, the elasticity of the material is single-valued and mutually independent, and the coordinate axes parallel to the multiple elastic principal directions are elastic principal axes, referring to Figure 2 the coordinate axes 1, 2, 3 in the embodiment. For materials with complex microstructures and large dispersions in stiffness properties, the multiple independent stiffness coefficients in the anisotropic stiffness matrix reflect their elastic properties and stiffness properties in different directions, and quantitative characterization of them can verify their stiffness properties accurately.

[0051] Furthermore, in some embodiments, the above S1 includes:

[0052] S11. Ultrasonic excitation signals are respectively emitted along the first incident plane and the second incident plane of the component to be measured at the first incident angle to obtain the first ultrasonic transmission data. During specific implementation, please refer to Figure 2, the first incident plane can be the above-mentioned P(1, 2) plane, the second incident plane can be the above-mentioned P(1, 3) plane, and the first incident angle can be the angle of θ = 0° along the normal direction of the surface of the component under test.

[0053] S12. Transmit ultrasonic excitation signals at multiple incident angles different from the first incident angle along the first incident plane of the component under test to obtain second ultrasonic transmission data.

[0054] S13. Transmit ultrasonic excitation signals at multiple incident angles different from the first incident angle along the second incident plane of the component under test to obtain third ultrasonic transmission data.

[0055] It can be understood that the order of S11 to S13 above is not limited. In specific implementation, S12 can be executed before S11, and S13 can also be executed before S11 and S12.

[0056] The above S2 includes:

[0057] S21. Calculate the first stiffness coefficient based on the ultrasonic excitation signal, the first ultrasonic transmission data, and the material-related parameters.

[0058] S22. Calculate multiple second stiffness coefficients based on the ultrasonic excitation signal, the second ultrasonic transmission data, the material-related parameters, and the first stiffness coefficient.

[0059] S23. Calculate multiple third stiffness coefficients based on the ultrasonic excitation signal, the third ultrasonic transmission data, the material-related parameters, the first stiffness coefficient, and the multiple second stiffness coefficients.

[0060] S24. Construct a stiffness matrix based on at least the first stiffness coefficient, the multiple second stiffness coefficients, and the multiple third stiffness coefficients.

[0061] In a specific embodiment, the above orthotropic material has 3 orthogonal elastic symmetry planes. The directions perpendicular to the symmetry planes are called the elastic principal directions, and there are 9 independent stiffness coefficients. In these three elastic principal directions, the elasticity of the material is single-valued and mutually independent. The coordinate axes parallel to these three elastic principal directions are the elastic principal axes. Refer to Figure 2 the coordinate axes 1, 2, and 3 in the embodiment. For materials with complex microstructures and large dispersions in stiffness properties, the 9 independent stiffness coefficients in the orthotropic stiffness matrix of the material reflect its elastic properties and stiffness properties in different directions. Quantitatively characterizing it can verify its stiffness performance accurately.

[0062] Moreover, considering that viscoelasticity also has complex effects on the mechanical properties of composite materials, viscoelasticity reflects the energy dissipation characteristics of materials under dynamic loads, which is crucial for shock absorption and sound absorption applications. Therefore, complex stiffness coefficients are used in the process of anisotropic stiffness characterization. The real part of the complex stiffness coefficient represents the stiffness characteristics of the composite material, and the imaginary part represents its damping characteristics. The method provided by the embodiments of the present disclosure can quantitatively characterize nine independent stiffness coefficients in the complex stiffness matrix of additively manufactured composite materials.

[0063] First, the stiffness matrix of an orthotropic material has nine independent stiffness coefficients, including C 11 、C 12 、C 13 、C 22 、C 23 、C 33 、C 44 、C 55 and C 66 a total of nine stiffness coefficients. Each stiffness coefficient is a complex number, where the real part represents the stiffness characteristics and the imaginary part represents the viscous properties.

[0064] When calculating the stiffness matrix corresponding to the orthotropic material, the above S1 further includes:

[0065] S14. Transmit ultrasonic excitation signals at multiple incident angles along the fourth incident plane of the test piece to obtain fourth ultrasonic transmission data. For specific implementation, please refer to Figure 2 . The fourth incident plane can be the above P(1, φ = 45°) plane.

[0066] Before S24 and after S23, the above S2 further includes:

[0067] S25. Calculate a plurality of fourth stiffness coefficients based on the ultrasonic excitation signal, the fourth ultrasonic transmission data, material-related parameters, the first stiffness coefficient, a plurality of second stiffness coefficients, and a plurality of third stiffness coefficients.

[0068] The above S24 specifically includes:

[0069] Construct a stiffness matrix based on the first stiffness coefficient, a plurality of second stiffness coefficients, a plurality of third stiffness coefficients, and a plurality of fourth stiffness coefficients. Among them, the stiffness coefficients of the stiffness matrix include C 11 、C 33 、C 55 、C 13 、C 22 、C 66 、C 12 、C 44 and C 23 . The first stiffness coefficient is C 11 . The second stiffness coefficient is C 33, C 55 , C 13 , the third stiffness coefficient is C 22 , C 66 , C 12 , the fourth stiffness coefficient is C 44 , C 23 .

[0070] Please refer to Figure 1 and Figure 2 , during specific implementation, the above S11 and S21 include:

[0071] Ultrasonic excitation signals are respectively emitted along the P(1, 2) plane and the P(1, 3) plane of the component under test at an incident angle of θ = 0°, and the first ultrasonic transmission data is obtained. The real and imaginary parts of the stiffness coefficient C 11 are calculated based on the ultrasonic excitation signal, the first ultrasonic transmission data, and the material-related parameters.

[0072] The above S12 and S22 include:

[0073] Ultrasonic excitation signals are emitted along the P(1, 2) plane of the component under test at multiple incident angles different from θ = 0°, and the first part of the second ultrasonic transmission data is obtained. The real and imaginary parts of the stiffness coefficient C 11 are calculated based on the ultrasonic excitation signal, the first part of the second ultrasonic transmission data, the material-related parameters, and the stiffness coefficient C 33 , C 55 , C 13 calculated above.

[0074] The above S13 and S23 include:

[0075] Ultrasonic excitation signals are emitted along the P(1, 3) plane of the component under test at multiple incident angles different from θ = 0°, and the second part of the second ultrasonic transmission data is obtained. The real and imaginary parts of the stiffness coefficient C 11 , C 33 , C 55 , C 13 are calculated based on the ultrasonic excitation signal, the second part of the second ultrasonic transmission data, the material-related parameters, and the stiffness coefficient C 22 , C 66 , C 12 calculated above.

[0076] The above S14 and S25 include:

[0077] Ultrasonic excitation signals are emitted along the P(1, φ = 45°) plane of the component under test at multiple incident angles different from θ = 0°, and the third ultrasonic transmission data is obtained. The multiple stiffness coefficients C11 , C 33 , C 55 , C 13 , C 22 , C 66 , C 12 , the stiffness coefficient C is calculated 44 , C 23 The real and imaginary parts of

[0078] Through the method provided by the above embodiments, all the stiffness coefficients in the stiffness matrix can be obtained, and then a complete stiffness matrix can be constructed to accurately characterize the stiffness performance of the workpiece to be measured.

[0079] In another specific embodiment provided by the present disclosure, there is an isotropic symmetry plane in the transversely isotropic material. Along any direction on this plane, its mechanical properties are the same, and it has 5 independent stiffness coefficients. In the stiffness matrix of the transversely isotropic material, C 22 = C 11 , C 23 = C 13 , C 44 = C 55 , C 66 = (C 11 - C 12 ) / 2. Therefore, for the transversely isotropic material, when detecting it, only 5 independent stiffness coefficients need to be obtained, and the remaining stiffness coefficients can be calculated from the above 5 independent stiffness coefficients.

[0080] When calculating the stiffness matrix corresponding to the workpiece to be measured of the transversely isotropic material, the above S11 and S21 include:

[0081] Ultrasonic excitation signals are respectively emitted along the P(1, 2) plane and the P(1, 3) plane of the workpiece to be measured at an incident angle of θ = 0°, and first ultrasonic transmission data are obtained. The stiffness coefficient C 11 The real and imaginary parts of

[0082] The above S12 and S22 include:

[0083] Ultrasonic excitation signals are emitted along the P(1, 2) plane of the workpiece to be measured at multiple incident angles different from θ = 0°, and the first part of the second ultrasonic transmission data is obtained. According to the ultrasonic excitation signals, the first part of the second ultrasonic transmission data, the material-related parameters, and the stiffness coefficient C 11 calculated above, the stiffness coefficients C 33 , C 55 , C 13 The real and imaginary parts of

[0084] The above S13 and S23 include:

[0085] Emit ultrasonic excitation signals at multiple incident angles different from θ = 0° along the P(1, 3) plane of the component to be measured, obtain the second ultrasonic transmission data of the second part, and calculate the real and imaginary parts of the stiffness coefficient C 11 , C 33 , C 55 , C 13 based on the ultrasonic excitation signal, the second ultrasonic transmission data of the second part, the material-related parameters, and the stiffness coefficient C 12 calculated above.

[0086] For a transversely isotropic material, only by emitting ultrasonic excitation signals along two incident planes (the above P(1, 2) plane and P(1, 3) plane) can the stiffness matrix be obtained. Specifically, after obtaining the stiffness coefficients C 11 , C 33 , C 55 , C 13 , C 12 through the above embodiments, then according to C 22 = C 11 , C 23 = C 13 , C 44 = C 55 , C 66 = (C 11 - C 12 ) / 2, the complete stiffness matrix can be obtained.

[0087] It should be noted that the above embodiments of the present disclosure provide two implementation manners: for a transversely isotropic material, five independent stiffness coefficients are obtained by emitting ultrasonic signals at multiple incident angles along two incident planes, and for an orthotropic material, nine independent stiffness coefficients are obtained by emitting ultrasonic signals at multiple incident angles along three incident planes. The incident planes and incident angles used in the above implementation manners are the minimum numbers required for calculating the stiffness coefficients. On this basis, increasing the number of incident planes or incident angles can further improve the calculation accuracy, which is beneficial to improving the accuracy of stiffness detection of automatic tape laying composites.

[0088] In some other embodiments, to achieve a more accurate characterization of the stiffness coefficient, the stiffness reduction caused by internal defects of the material of the component to be measured needs to be considered and the above method needs to be corrected.

[0089] In some embodiments, the process of calculating the first stiffness coefficient and the second stiffness coefficient (the same applies to all the above stiffness coefficients) includes:

[0090] The first stiffness coefficient and the second stiffness coefficient are obtained by inverse calculation based on mathematical optimization methods (such as the simplex method, Newton's method, etc.).

[0091] For example, the simplex method is an iterative method for minimizing an n-variable function. For the optimization problem of n-dimensional variables, an n+1-dimensional simplex is initially constructed, the function values of the simplex vertices are calculated and analyzed and compared, and then the vertex with the highest value is replaced by another point to construct new vertices and a simplex until the convergence condition is reached. The simplex will adapt to the fluctuations of the function and can always converge to a certain minimum solution. That is, in the case where the objective function is not sensitive to its independent variables, the simplex method can still find a certain solution. This method has been proven to be effective and computationally compact, and it can find an approximate optimal solution far from the initial value. The simplex algorithm starts from the initial pre-estimated values, which may be very different from the expected values (about 50%), and after several iterations, good estimated values (within 10%) can be given.

[0092] The specific process of using the simplex method for inversion in the above embodiments includes:

[0093] 1. Find an initial basic feasible solution, that is, input multiple initial stiffness coefficient values.

[0094] 2. According to the transmission coefficient analysis calculation program, calculate the objective function value (i.e., the transmission spectrum) obtained by the current stiffness coefficient, and check whether it is possible to improve the objective function value by changing the stiffness coefficient value.

[0095] 3. If there is a possibility of improvement, select an entering variable and a leaving variable, perform a basis transformation, and move to a new basic feasible solution.

[0096] 4. Repeat steps 3 and 4 until the objective function value cannot be further improved. At this time, the obtained objective function value, that is, the theoretical transmission spectrum, is closest to the above-mentioned ultrasonic transmission spectrum measured experimentally (measured by the least squares method).

[0097] It should be noted that the method provided by the embodiments of the present disclosure uses ultrasonic multi-plane multi-angle transmission data as calculation data, and can obtain the stiffness information of the test piece in each direction, thereby realizing the non-destructive quantitative characterization of the anisotropic stiffness parameters of the composite material. To meet the experimental plane wave assumption and homogeneous medium assumption and realize the accurate characterization of the anisotropic stiffness coefficient, it is necessary to select appropriate incident signal frequencies, incident signal bandwidths, and plane wave incident angles during detection. Optionally, the ultrasonic non-destructive characterization method for the stiffness of the automatic tape laying composite material further includes: setting the signal frequency, probe size, and incident angle of the ultrasonic excitation signal; specifically:

[0098] Set the signal frequency f of the ultrasonic excitation signal such that f satisfies: c / d < f < c / dply , where c represents the ultrasonic propagation speed in the test piece, d represents the dimension of the test piece along the ultrasonic transmission direction, and d ply represents the thickness of the carbon fiber tape inside the test piece. For a multi-layer material test piece, using ultrasonic waves with a lower frequency can make it regarded as a homogeneous medium. The upper limit of the frequency of the ultrasonic excitation signal is determined by the material-related parameters of the test piece. Therefore, to meet the homogeneous medium assumption, it is necessary to set the signal frequency of the ultrasonic excitation signal. An optional implementation provided by the present disclosure is 0.1 MHz ≤ f ≤ 1 MHz. It should be noted that the present disclosure is only illustrated by this example and is not limited thereto.

[0099] Set the size l of the ultrasonic excitation signal probe such that l > 3c / f. An optional implementation provided by the present disclosure is l >> c / f. For the signal bandwidth of the ultrasonic excitation signal, it is necessary to ensure that at least 30 frequency point data are recorded for the ultrasonic transmission data. Specifically, during implementation, for each incident angle, the frequency bandwidth of the ultrasonic transmission data is directly related to the richness of the data. It is necessary to select an ultrasonic excitation signal with a sufficiently wide frequency band and record at least 30 frequency point data.

[0100] Set the incident angle of the ultrasonic excitation signal so that the incident angle is between zero and the critical refraction angle. Specifically, during implementation, based on the given frequency range that meets the above plane wave condition and homogeneous condition, the above incident angle can be the entire angular region from zero (normal incidence) to the second critical refraction angle, which contains all the information required to optimize the stiffness parameter. The second critical refraction angle is θ’ = arcsin(v water / v s-plate ), where v water is the propagation speed of sound waves in water, and v s-plate is the shear wave speed in the plate. Appropriate multiple incident angles can be selected within this angular range as the above plane wave incident angles. Specifically, during implementation, the maximum step size of the selected incident angle is 5°.

[0101] Please refer to Figure 1 , in some embodiments, the above S1 includes:

[0102] Immerse the test piece in a liquid and emit ultrasonic excitation signals at at least two incident angles along at least two incident planes of the test piece to obtain ultrasonic transmission data.

[0103] Water immersion ultrasonic testing is a technique that uses ultrasonic waves to propagate in water and reflect back to the probe to detect internal defects in materials. It can be applied in the field of non-destructive testing and is used to evaluate the internal structure of materials, detect defects such as cracks, pores, and inclusions. Water, as a coupling medium, can effectively transmit ultrasonic energy and reduce attenuation and reflection losses caused by air or other non-coupling media. Moreover, compared with direct contact ultrasonic testing, the water immersion method can provide more stable coupling conditions to ensure the effective transmission of ultrasonic energy into the workpiece. It should be noted that the embodiments of the present disclosure are only illustrated by taking water immersion ultrasonic testing as an example and are not limited thereto. For example, air-coupled ultrasonic testing can also be used.

[0104] Specifically, in water immersion ultrasonic testing, the above ultrasonic excitation signal is emitted by an ultrasonic transducer. The signal frequency that the ultrasonic transducer can emit in water needs to meet the above embodiments. Specifically, a transducer with a corresponding size larger than the wavelength of the sound wave in the immersion medium (i.e., water) can obtain a plane wave, that is, the radius R of the wafer of the ultrasonic transducer >> λ water = v water / f, λ water is the wavelength of the sound wave in water, and v water is the propagation speed of the sound wave in water.

[0105] In some embodiments, the above workpiece to be measured has stiffness non-uniformity. At this time, the above S1 includes: emitting ultrasonic excitation signals along at least two incident planes in at least two regions of the workpiece to be measured at at least two incident angles, and then performing stiffness detection on multiple regions of the workpiece to be measured respectively.

[0106] The above S2 includes: respectively calculating the stiffness parameters of at least two regions of the workpiece to be measured according to the ultrasonic excitation signal, ultrasonic transmission data, and material-related parameters.

[0107] Specifically, the above workpiece to be measured can be composed of composite materials, and the non-uniformity of the materials leads to the above stiffness non-uniformity; in other embodiments, the above workpiece to be measured can also be generated by additive manufacturing, and its layer-by-layer processing characteristics lead to the above stiffness non-uniformity.

[0108] Additive manufacturing technology, also known as 3D printing technology, is a technology for manufacturing solid parts by the method of layer-by-layer material accumulation based on three-dimensional CAD data. As an advanced forming manufacturing process, additive manufacturing technology can meet the efficient and flexible manufacturing requirements of various complex products, realize the integrated manufacturing and forming of various complex components such as honeycomb lattice structures and stiffened structures, and has broad application prospects in the fields of aerospace, transportation, energy and chemical engineering, architecture, bioengineering, etc.

[0109] Compared with the traditional molding process, additive manufacturing technology has a higher degree of freedom in processing and manufacturing, and has unique advantages in preparing components with complex shapes or complex internal structures. However, for additive manufacturing composites, different material systems and processing parameters result in complex and variable internal structures, with differences in fiber volume fraction, porosity, and interface conditions, which in turn lead to a large dispersion in the stiffness coefficients of additive manufacturing composites. Therefore, measuring and characterizing the stiffness parameters of composites is of great significance both in design verification and in the application level.

[0110] In some embodiments, the ultrasonic transmission data includes ultrasonic transmission spectra, the material-related parameters include the material density of the test piece and the size of the test piece in the direction normal to the incident plane (when the test piece is a flat plate, the size of the test piece in the direction normal to the incident plane can be the thickness of the test piece), and the above S2 includes:

[0111] The stiffness parameters of the test piece are calculated based on the ultrasonic transmission spectra, the material density of the test piece, the size of the test piece in the direction normal to the incident plane, the frequency of the ultrasonic excitation signal, and the incident angle of the ultrasonic excitation signal.

[0112] The plane wave transmission spectrum (i.e., the above ultrasonic transmission spectrum) is the spectrum of the transmitted sound field when the test piece (specifically a flat plate) is incident by a plane wave. If the obtained ultrasonic transmission spectrum is divided by the incident plane wave spectrum, the transmission coefficient of the test piece can be obtained. For any test piece, under the condition of known material-related parameters (density, size (thickness of the flat plate), stiffness parameters, etc.), based on the Christoffel equation and the refraction law of ultrasonic waves at the water-solid interface, the plane wave transmission coefficient of the test piece under water immersion conditions at any incident angle and any frequency can be calculated. For a flat test piece with known material-related parameters, the transmission coefficient establishes the relationship between the stiffness parameters and the transmitted sound field. Multiplying the incident plane wave signal by the calculated transmission coefficient, the theoretical ultrasonic transmission spectrum can be calculated.

[0113] Based on the above theoretical calculations, evaluate the sensitivity of the ultrasonic transmission spectra corresponding to the ultrasonic signals incident at different angles in different ultrasonic incident planes to the changes in each independent stiffness parameter, and determine the ultrasonic transmission spectra required for calculating each stiffness parameter according to the sensitivity analysis results.

[0114] For a test piece with unknown stiffness parameters, by obtaining the ultrasonic transmission spectrum through the method provided in the above embodiments, the corresponding estimated stiffness parameters can be calculated by inverse deduction. By continuously adjusting the estimated stiffness parameters through an optimization algorithm, the corresponding theoretical transmission spectrum is continuously approximated to the experimentally measured ultrasonic transmission spectrum. When the error between the two is less than a minimum value, it is considered that the value of the estimated stiffness parameter is the true value of the stiffness parameter of the test piece.

[0115] Based on the same inventive concept, the present disclosure also provides an ultrasonic non-destructive characterization system for the stiffness of automatic tape laying composites. Figure 3 For a schematic diagram of the modules of an ultrasonic non-destructive characterization system for the stiffness of automatic tape laying composites provided by an embodiment of the present disclosure, please refer to Figure 3 , the ultrasonic non-destructive characterization system for the stiffness of automatic tape laying composites includes:

[0116] An ultrasonic detection module 10, configured to emit ultrasonic excitation signals at at least two incident angles along at least two incident planes of a test piece to obtain ultrasonic transmission data, wherein the test piece is made of an anisotropic material. Specifically, the ultrasonic detection module 10 is configured to cooperate with the position and angle of the test piece to emit ultrasonic excitation signals at corresponding positions to obtain ultrasonic transmission data.

[0117] A stiffness calculation module 20, configured to calculate the stiffness parameters of the test piece according to the ultrasonic excitation signals, the ultrasonic transmission data, and material-related parameters.

[0118] The device provided by the embodiment of the present disclosure uses ultrasonic multi-plane and multi-angle transmission data as calculation data, and can obtain the stiffness information of the test piece in each direction, thereby realizing non-destructive quantitative characterization of the anisotropic stiffness parameters of the composite material.

[0119] For the specific hardware of the above device, reference may be made to the above embodiments, which will not be elaborated here.

[0120] For the convenience of description, the above detection system is described by dividing it into various modules according to functions. Of course, when implementing the present disclosure, the functions of each module can be realized in the same or multiple software and / or hardware.

[0121] The device of the above embodiment is used to implement the corresponding ultrasonic non-destructive characterization method in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be elaborated here.

[0122] Please refer to Figure 3 , in an alternative embodiment of the present disclosure, the ultrasonic detection module 10 includes a high-precision turntable, and the high-precision turntable is at least used to obtain ultrasonic transmission data at different angles. Specifically, the high-precision turntable is used for precise regulation of the position of the test piece, and rotates the test piece at a certain angular step to obtain multi-plane and multi-angle ultrasonic transmission spectra required for characterizing the anisotropic stiffness coefficient. Optionally, the high-precision turntable can be a robotic arm. The present disclosure only takes this as an example for illustration and is not limited thereto.

[0123] Please continue to refer to Figure 3, in an alternative embodiment of the present disclosure, the ultrasonic detection module 10 includes an ultrasonic transducer. The ultrasonic transducer includes a receiving transducer and an exciting transducer, and the ultrasonic transducer is at least used to characterize the stiffness coefficients of different regions of the workpiece to be measured; the receiving transducer is at least used to obtain a complete ultrasonic multi-angle plane wave transmission sound field. It should be noted that the ultrasonic transducer is used to move multiple receiving positions for each incident ultrasonic excitation signal to obtain a complete ultrasonic multi-angle plane wave transmission sound field.

[0124] Based on the ultrasonic non-destructive characterization method and system proposed in the above embodiments of the present disclosure, the embodiments of the present disclosure also designed and built a multi-angle and multi-plane ultrasonic transmission test platform. Figure 4 For a structural schematic diagram of an ultrasonic transmission test platform provided by an embodiment of the present disclosure, please refer to Figure 4 , the test platform includes a three-axis motion control module 01, an ultrasonic plane wave excitation probe and fixture 02, a three-axis motion control module 03, an ultrasonic plane wave receiving probe and fixture 04, a single-axis motion control module 05, a turntable and fixture 06, and a workpiece to be measured 07. The above ultrasonic transmission test platform uses a water immersion ultrasonic transducer to excite and receive the ultrasonic sound field, and realizes the multi-angle ultrasonic transmission characterization of the workpiece to be measured by automatically controlling the turntable. Other devices in the experiment include a water tank, a support frame, various adapter connectors, a spirit level, a laser digital display inclinometer, etc.

[0125] Specifically, the embodiments of the present disclosure designed a high-precision and automated sample rotation and positioning scheme. The repeat positioning accuracy of the high-precision turntable is 0.005°, which can avoid the angle cumulative error caused by multi-angle rotation. The precise control of the sample position is realized, and the sample can be rotated at a certain angle step to obtain the multi-plane and multi-angle ultrasonic transmission spectra required for characterizing the anisotropic stiffness coefficient.

[0126] The embodiments of the present disclosure also designed an ultrasonic transducer motion control system that meets the detection requirements to realize the automatic adjustment of the positions of the ultrasonic exciting transducer and the receiving transducer. The displacement stage stroke of the exciting / receiving transducer is 460 mm, which can provide a sufficient lateral movement range to receive the multi-angle transmission sound field spectra of the workpiece to be measured. The motion control system uses a cross laser positioning auxiliary device to ensure the installation accuracy of the test piece; an integrated customized adapter component is used to reduce the installation cumulative error between the displacement stage and the probe fixture. Based on this ultrasonic transducer motion control system, the exciting / receiving transducer can be moved to characterize the stiffness coefficients of different regions of the workpiece to be measured, and the position of the receiving transducer can be moved to obtain a complete ultrasonic multi-angle transmission sound field.

[0127] In specific implementation, the ultrasonic transducer used in the above method can be the water immersion broadband ultrasonic transducer V398-SU produced by Olympus. Its center frequency is 500 kHz, the bandwidth can reach 50%, the available frequency range in actual application is 100 kHz to 1000 kHz, and the diameter of the excitation surface is 38 mm. This probe has a relatively wide frequency band, a larger frequency range that can be selected in the inversion calculation, and more transmission coefficient characteristics included at the same angle. In other embodiments, those skilled in the art can also select other models of ultrasonic transducers according to the above detection requirements, and no further limitation is imposed here.

[0128] In the experiment, the transmitting and receiving mode of the ultrasonic transducer is one transmitting and one receiving. The ultrasonic signal frequency emitted by the transducer with a lower center frequency is lower, which can meet the condition that the ultrasonic wavelength propagating inside the workpiece to be measured is greater than the thickness of the flat plate of the workpiece to be measured, so that the workpiece to be measured can be regarded as a homogeneous medium. The lower limit of the frequency used needs to meet the plane wave assumption, that is, the diameter of the excitation surface of the ultrasonic transducer (38 mm) is much larger than the ultrasonic wavelength. The frequency range that can be used for non-destructive characterization of the stiffness coefficient of the workpiece to be measured in the inversion is 100 kHz to 800 kHz.

[0129] Based on the above stiffness characterization method and test platform, the present disclosure embodiment has carried out stiffness detection on some samples. Specifically, to meet the homogeneous medium assumption, the incident excitation signal is selected as a Toneburst signal with a frequency of 400 kHz and including three cycles as the ultrasonic excitation signal. Figure 5 This is the time-domain diagram of an ultrasonic excitation signal provided by the present disclosure embodiment. Figure 6 This is the frequency-domain diagram of an ultrasonic excitation signal provided by the present disclosure embodiment. Please refer to Figure 5 and Figure 6 , the time-domain diagram of the ultrasonic excitation signal is as shown in Figure 5 and the frequency-domain diagram is as shown in Figure 6 . After being amplified by a power amplifier, this signal is input into the ultrasonic transducer to excite an ultrasonic plane wave signal in the workpiece to be measured.

[0130] For each plane to be measured, the turntable is controlled to rotate in steps of 4°, and the rotation range is 0° to 48°. The ultrasonic multi-angle transmission sound pressure time-domain signals of the additive manufacturing composite material planes P(1, 2), P(1, 3) and P(1, φ = 45°) are collected. Since the ultrasonic wave will shift in position during propagation, it is necessary to move the probe position so that the transmitted wave can be completely received. The probe is moved 38 mm and 76 mm successively along the refraction direction to receive the signal again. The received transmission signals at the same angle are superimposed in the frequency domain to obtain the complete ultrasonic multi-angle transmission sound field.

[0131] The test piece B is a T700 / PA automatic placement composite material with a ply orientation of [0°]. For the test piece B, three characterization regions are selected to collect its multi-plane and multi-angle ultrasonic transmission signals respectively. The same test piece is selected and mechanical tests of cut and stretched specimens are carried out in different regions by the methods in the related art, and the tensile modulus of the material characterized by the mechanical test is E 22 = 4.55 GPa, E 33 = 109.12 GPa.

[0132] Figure 7 This is a stiffness matrix diagram provided by an embodiment of the present disclosure. Figure 8 This is another stiffness matrix diagram provided by an embodiment of the present disclosure. Figure 9 This is still another stiffness matrix diagram provided by an embodiment of the present disclosure. Please refer to Figures 7 - 9 , the anisotropic stiffness matrix of region 1 of the test piece B calculated by the method of the above embodiment of the present disclosure is as Figure 7 shown, and the corresponding calculated tensile modulus is E 22 = 2.77 GPa, E 33 = 116.45 GPa; the anisotropic stiffness matrix of region 2 is as Figure 8 shown, and the corresponding calculated tensile modulus is E 22 = 6.72 GPa, E 33 = 118.03 GPa; the anisotropic stiffness matrix of region 3 is as Figure 9 shown, and the corresponding calculated tensile modulus is E 22 = 4.69 GPa, E 33 = 103.15 GPa. Comparing the results measured by the method provided by the embodiment of the present disclosure with the results measured by the methods in the related art, the relative error of the average value of E 22 is 3.95%, and the relative error of the average value of E 33 is 3.13%, showing good consistency.

[0133] The test piece C is a T700 / PA automatic placement composite material with a ply orientation of [0° / 45° / 90° / -45°]. For the test piece C, three characterization regions are selected to collect its multi-plane and multi-angle ultrasonic transmission signals respectively. The same test piece is selected and mechanical tests of cut and stretched specimens are carried out in different regions by the methods in the related art, and the tensile modulus of the material characterized by the mechanical test is E 22 = E 33 = 30.65 GPa.

[0134] Figure 10 This is yet another stiffness matrix diagram provided by an embodiment of the present disclosure. Figure 11 This is yet another stiffness matrix diagram provided by an embodiment of the present disclosure. Figure 12Another stiffness matrix diagram provided by the embodiments of the present disclosure. Please refer to Figures 10 - 12 , the anisotropic stiffness matrix of region 1 of the workpiece C to be measured calculated by the method of the above embodiments of the present disclosure is as Figure 10 shown. The corresponding calculated tensile modulus is E 22 = 16.32 GPa, E 33 = 11.13 GPa; the anisotropic stiffness matrix of region 2 is as Figure 11 shown. The corresponding calculated tensile modulus is E 22 = 32.9 GPa, E 33 = 33.31 GPa; the anisotropic stiffness matrix of region 3 is as Figure 12 shown. The corresponding calculated tensile modulus is E 22 = 16.21 GPa, E 33 = 11.20 GPa. Comparing the results measured by the method provided by the embodiments of the present disclosure with the results measured by the methods in the related art, the relative error of the average value is 8.01%, showing good consistency.

[0135] Through the above experimental tests, the accuracy of the ultrasonic characterization method for the anisotropic stiffness coefficient of the additive composite provided by the embodiments of the present disclosure is verified. The characterization results are compared and verified with the traditional destructive mechanical test results such as tension, compression, torsion, and shear of the same batch of samples, and the characterization error ≤ 10%.

[0136] It should be noted that the method of the embodiments of the present disclosure can be executed by a single device, such as a computer or a server. The method of this embodiment can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In this distributed scenario, one of the multiple devices can only execute one or more steps of the method of the embodiments of the present disclosure, and these multiple devices will interact with each other to complete the above method.

[0137] It should be noted that some embodiments of the present disclosure have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be executed in a different order from that in the above embodiments and still achieve the desired results. Additionally, the processes depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0138] Based on the same inventive concept, the present disclosure also provides an electronic device, Figure 13 A schematic diagram of the hardware structure of an electronic device provided by the embodiments of the present disclosure. Please refer to Figure 13 , the electronic device may include a processor 1101 and a memory 1102 storing computer program instructions.

[0139] Specifically, the above-mentioned processor 1101 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured as one or more integrated circuits for implementing the embodiments of the present disclosure.

[0140] The memory 1102 may include a mass storage for information or instructions. By way of example and not limitation, the memory 1102 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disc, a magneto-optical disc, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. In a suitable case, the memory 1102 may include removable or non-removable (or fixed) media. In a suitable case, the memory 1102 may be internal or external to the integrated gateway device. In a specific embodiment, the memory 1102 is a non-volatile solid-state memory. In a specific embodiment, the memory 1102 includes a read-only memory (ROM). In a suitable case, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically alterable ROM (EAROM), or a flash memory, or a combination of two or more of these.

[0141] The processor 1101 reads and executes the computer program instructions stored in the memory 1102 to perform the steps of the ultrasonic non-destructive characterization method for the stiffness of the automatically laid composite material provided by the embodiments of the present disclosure.

[0142] In one example, the electronic device may further include a transceiver 1103 and a bus 1104. Among them, as Figure 13 shown, the processor 1101, the memory 1102, and the transceiver 1103 are connected through the bus 1104 to complete communication with each other.

[0143] Bus 1104 includes hardware, software, or both. By way of example and not limitation, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side BUS (FSB), a Hyper Transport (HT) interconnect, an Industrial Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a MicroChannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable bus or a combination of two or more of these. Where appropriate, bus 1104 may include one or more buses. Although embodiments of the present disclosure describe and illustrate specific buses, the present disclosure contemplates any suitable bus or interconnect.

[0144] The following are embodiments of a computer-readable storage medium provided by embodiments of the present disclosure. The computer-readable storage medium and the ultrasonic non-destructive characterization method for the stiffness of the automatic tape laying composite material in the above embodiments belong to the same inventive concept. Details not described in detail in the embodiments of the computer-readable storage medium may refer to the embodiments of the ultrasonic non-destructive characterization method for the stiffness of the automatic tape laying composite material.

[0145] This embodiment provides a storage medium containing computer-executable instructions that, when executed by a computer processor, are used to execute an ultrasonic non-destructive characterization method for the stiffness of an automatic tape laying composite material.

[0146] Of course, the computer-executable instructions of a storage medium containing computer-executable instructions provided by embodiments of the present disclosure are not limited to the above method operations, and may also execute related operations in the ultrasonic non-destructive characterization method for the stiffness of the automatic tape laying composite material provided by any embodiment of the present disclosure.

[0147] From the above description of the embodiments, those skilled in the art can clearly understand that the present disclosure can be implemented by means of software and necessary general hardware. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present disclosure, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a floppy disk, read-only memory (ROM), random access memory (RAM), flash memory (FLASH), hard disk, or optical disc of a computer, etc., including several instructions to enable a computer cloud platform (which can be a personal computer, server, or network cloud platform, etc.) to execute the ultrasonic non-destructive characterization method for the stiffness of the automatic tape laying composite material provided in each embodiment of the present disclosure.

[0148] As can be seen from the above embodiments, the ultrasonic non-destructive characterization method and system for the stiffness of the automatic tape laying composite material provided by the present disclosure have at least achieved the following beneficial effects:

[0149] The present disclosure provides an ultrasonic non-destructive characterization method and system for the stiffness of the automatic tape laying composite material. The ultrasonic non-destructive characterization method uses ultrasonic multi-plane multi-angle transmission data as calculation data, and can obtain the stiffness information of the test piece in each direction, thereby realizing the non-destructive quantitative characterization of the anisotropic stiffness parameters along the composite material.

[0150] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including the above element.

[0151] The above are only specific embodiments of the present disclosure, enabling those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments described above herein, but rather will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ultrasonic non-destructive characterization method for the stiffness of an automated tape laying composite material, characterized in that: include: Transmitting ultrasonic excitation signals at at least two incident angles along at least two incident planes of a test piece to obtain ultrasonic transmission data, wherein the test piece is made by an automatic tape laying process; The stiffness parameter of the test piece is calculated according to the ultrasonic excitation signal, the ultrasonic transmission data and material-related parameters; wherein the material-related parameters at least include the thickness and density of the test piece.

2. The method according to claim 1, characterized in that: The stiffness parameters include a stiffness matrix; The step of calculating the stiffness parameter of the test piece according to the ultrasonic excitation signal, the ultrasonic transmission data and material related parameters includes: Calculating the stiffness matrix of the test piece according to the ultrasonic excitation signal, the ultrasonic transmission data and the material-related parameters; The method for calculating the stiffness matrix of the test piece includes: The stiffness matrix that minimizes the objective function is obtained through the inversion algorithm. The objective function is: Where f represents the selected frequency, θ represents the ultrasonic oblique incident angle, C ij represents the stiffness coefficient to be optimized, represents the theoretically calculated transmitted sound field, represents the transmitted sound field obtained from the experiment.

3. The method according to claim 2, characterized in that The step of transmitting ultrasonic excitation signals at at least two incident angles along at least two incident planes of the test object to obtain ultrasonic transmission data includes: The ultrasonic excitation signal is emitted at a first incident angle along a first incident plane and a second incident plane of the test piece respectively to obtain first ultrasonic transmission data; transmitting the ultrasonic excitation signal along the first incident plane of the test piece at a plurality of incident angles different from the first incident angle to obtain second ultrasonic transmission data; transmitting the ultrasonic excitation signal along the second incident plane of the test piece at a plurality of incident angles different from the first incident angle to obtain third ultrasonic transmission data; The step of calculating the stiffness matrix of the test piece according to the ultrasonic excitation signal, the ultrasonic transmission data and the material related parameters includes: Calculating a first stiffness coefficient according to the ultrasonic excitation signal, the first ultrasonic transmission data and the material-related parameters; Calculating a plurality of second stiffness coefficients according to the ultrasonic excitation signal, the second ultrasonic transmission data, the material-related parameters and the first stiffness coefficient; Calculating a plurality of third stiffness coefficients according to the ultrasonic excitation signal, the third ultrasonic transmission data, the material-related parameters, the first stiffness coefficient, and a plurality of the second stiffness coefficients; The stiffness matrix is ​​constructed based on at least the first stiffness coefficient, a plurality of the second stiffness coefficients, and a plurality of the third stiffness coefficients.

4. The method according to claim 3, characterized in that The method of transmitting ultrasonic excitation signals at at least two incident angles along at least two incident planes of the test object to obtain ultrasonic transmission data further includes: transmitting the ultrasonic excitation signal at a plurality of incident angles along a fourth incident plane of the test piece to obtain fourth ultrasonic transmission data; The step of calculating the stiffness matrix of the test piece according to the ultrasonic excitation signal, the ultrasonic transmission data and the material related parameters further includes: Calculating a plurality of fourth stiffness coefficients according to the ultrasonic excitation signal, the fourth ultrasonic transmission data, the material-related parameters, the first stiffness coefficient, a plurality of the second stiffness coefficients, and a plurality of the third stiffness coefficients; The stiffness matrix is ​​constructed based on the first stiffness coefficient, a plurality of the second stiffness coefficients, a plurality of the third stiffness coefficients, and a plurality of the fourth stiffness coefficients, wherein the stiffness coefficients of the stiffness matrix include C 11 , C 33 , C 55 , C 13 , C 22 , C 66 , C 12 , C 44 and C 23 , the first stiffness coefficient is C 11 , the second stiffness coefficient is C 33 , C 55 , C 13 , the third stiffness coefficient is C 22 , C 66 , C 12 , the fourth stiffness coefficient is C 44 , C 23 .

5. The method according to claim 1, characterized in that Also includes: Setting the signal frequency, probe size and incident angle of the ultrasonic excitation signal; The setting of the signal frequency, probe size and incident angle of the ultrasonic excitation signal includes: The signal frequency f of the ultrasonic excitation signal is set so that f satisfies: c / d <f<c / d ply , where c represents the ultrasonic wave propagation velocity in the test piece, d represents the size of the test piece along the ultrasonic wave transmission direction, and d ply Indicates the thickness of the carbon fiber tape inside the test piece; Setting the size l of the ultrasonic excitation signal probe so that l>3c / f is satisfied; The incident angle of the ultrasonic excitation signal is set so that the incident angle is between zero and a critical refraction angle.

6. The method according to claim 1, characterized in that The test piece has non-uniform rigidity; The transmitting of ultrasonic excitation signals at at least two incident angles along at least two incident planes of the test object comprises: Transmitting the ultrasonic excitation signal at at least two incident angles along at least two incident planes of at least two regions of the object to be tested; The step of calculating the stiffness parameter of the test piece according to the ultrasonic excitation signal, the ultrasonic transmission data and material related parameters includes: The stiffness parameters of at least two regions of the test piece are respectively calculated according to the ultrasonic excitation signal, the ultrasonic transmission data and material related parameters.

7. The method according to claim 1, characterized in that The step of transmitting ultrasonic excitation signals at at least two incident angles along at least two incident planes of the test object to obtain ultrasonic transmission data includes: The test piece is immersed in liquid, and the ultrasonic excitation signal is emitted along at least two incident planes of the test piece at at least two incident angles to obtain the ultrasonic transmission data.

8. An ultrasonic non-destructive characterization system for the stiffness of composite materials for automatic tape laying, characterized in that: include: An ultrasonic testing module, used for transmitting ultrasonic excitation signals at at least two incident angles along at least two incident planes of a test piece to obtain ultrasonic transmission data, wherein the test piece is made by an automatic tape laying process; The stiffness calculation module is used to calculate the stiffness parameters of the test piece according to the ultrasonic excitation signal, the ultrasonic transmission data and material related parameters.

9. The ultrasonic nondestructive characterization system for the stiffness of composite materials for automatic tape laying according to claim 8, characterized in that: The ultrasonic detection module includes a high-precision turntable, and the high-precision turntable is at least used to obtain the ultrasonic transmission data at different angles.

10. The ultrasonic nondestructive characterization system for the stiffness of composite materials for automatic tape laying according to claim 8, characterized in that: The ultrasonic detection module includes an ultrasonic transducer, the ultrasonic transducer includes a receiving transducer and an excitation transducer, and the ultrasonic transducer is at least used to characterize the stiffness coefficient of different areas of the test piece; The receiving transducer is at least used to obtain a complete ultrasonic multi-angle plane wave transmission sound field.

Images