A high aspect ratio optimization method and system for 1-3 piezoelectric composites

Abstract

The application relates to the technical field of piezoelectric composite materials, underwater acoustic transducers and ultrasonic sensor design, in particular to a high-width ratio optimization method and system of a 1-3 type piezoelectric composite material, which comprises the following steps: a finite element simulation model is established; piezoelectric ceramic volume fractions are kept unchanged, and multiple groups of different piezoelectric ceramic column height-width ratios are set; frequency domain electromechanical coupling analysis is carried out on each finite element model, complex impedance response curves are obtained, complex impedance spectrum characteristics are extracted, effective electromechanical coupling coefficients are calculated, a relationship curve of the coefficients changing with the height-width ratios is established, and each local abnormal peak value is located; in combination with the complex impedance spectrum characteristics, it is preliminarily judged whether each local abnormal peak value exists in mode coupling suspicion, and the suspicious ones are marked as to-be-verified samples; mode analysis is carried out on each sample, and thickness direction mode proportions are calculated; in combination with the preliminary judgment results of each sample and the corresponding thickness direction mode proportions, mode coupling abnormal height-width ratio intervals are judged, and an optimized height-width ratio design interval of the piezoelectric ceramic column is screened.

Description

Technical Field

[0001] This application relates to the fields of piezoelectric composite materials, underwater acoustic transducers, and ultrasonic sensor design technology, and in particular to a method and system for optimizing the aspect ratio of type 1-3 piezoelectric composite materials. Background Technology

[0002] Piezoelectric composite materials are typically composed of piezoelectric ceramic pillars arranged along the thickness direction and a polymer matrix. They have high electromechanical coupling capability, low acoustic impedance and good broadband characteristics, and are therefore widely used in underwater acoustic transducers, medical ultrasound probes and related acoustic measurement and control systems.

[0003] In existing technologies, the equivalent performance of piezoelectric composite materials is typically analyzed using the Smith equivalent medium theory or other homogenized models through finite element method simulation. Smith's 1-3 piezoelectric composite material model treats the composite material as an equivalent homogeneous medium for analyzing its hydrophone-related performance. Kim et al. studied the relationship between the electromechanical coupling coefficient and aspect ratio of piezoelectric resonators, pointing out that the electromechanical coupling coefficient is closely related to the resonator's geometry. Reynolds et al. analyzed the inter-column transverse parasitic resonance problem in 1-3 piezoelectric composite materials through experiments and the finite element method, indicating that while this type of composite material has performance advantages, it also introduces additional parasitic resonances. Furthermore, existing patents such as CN108807658B disclose a low mechanical quality factor 1-3 type piezoelectric composite material and its preparation method, mainly targeting broadband piezoelectric transducers and sonar applications. However, existing technologies still have the following shortcomings: 1. Traditional Smith equivalent theory mainly describes the changes in macroscopic equivalent parameters, which is difficult to reflect the transverse modes, shear modes and local column vibration modes in piezoelectric ceramic columns with finite aspect ratios.

[0004] 2. Existing aspect ratio optimization methods often directly rely on the effective electromechanical coupling coefficient. Judging the quality of a structure by its size can easily lead to misjudging abnormal peaks caused by local modal coupling as improvements in the intrinsic properties of the material.

[0005] 3. Existing finite element analysis typically focuses on the impedance curve, resonant frequency, or electromechanical coupling coefficient itself, lacking a method that incorporates the stray peaks and main peak migration patterns of the complex impedance spectrum. A high aspect ratio screening method that combines mutation characteristics and modal purity.

[0006] 4. For underwater acoustic transducers, if a high aspect ratio with strong local mode coupling is selected, parasitic peaks, unstable bandwidth, fluctuations in receiver sensitivity, or distortion in transmit response may occur in the operating frequency band, thereby affecting the overall performance of the transducer.

[0007] Therefore, there is a need for an optimization method for type 1-3 piezoelectric composite materials that can identify the source of abnormal peak values ​​of the effective electromechanical coupling coefficient during aspect ratio changes and can screen the stable thickness modal working range. Summary of the Invention

[0008] The purpose of this application is to overcome the limitations of existing technologies that rely solely on homogenization theory or a single... When selecting aspect ratios for indicators, it is easy to overlook the problems of local modal coupling and parasitic peak effects. Therefore, this paper provides a method and system for optimizing the aspect ratio of type 1-3 piezoelectric composite materials.

[0009] To solve the above-mentioned technical problems, the aspect ratio optimization method for type 1-3 piezoelectric composite materials provided in this application includes the following steps: Step 1: Establish finite element simulation models of type 1-3 piezoelectric composite materials; Step 2: Keep the volume fraction of piezoelectric ceramics constant, and set multiple sets of different aspect ratios for the piezoelectric ceramic columns; Step 3: Perform frequency domain electromechanical coupling analysis on the finite element models corresponding to each aspect ratio to obtain the complex impedance response curves as a function of frequency for each aspect ratio; Step 4: Extract the corresponding complex impedance spectrum features from each complex impedance response curve, and calculate the effective electromechanical coupling coefficient corresponding to each aspect ratio. Establish the relationship curve between the effective electromechanical coupling coefficient and the aspect ratio; Step 5: Based on the relationship curve of effective electromechanical coupling coefficient with aspect ratio, locate each local abnormal peak; combine the complex impedance spectrum characteristics corresponding to each aspect ratio to preliminarily determine whether each local abnormal peak is suspected of modal coupling, and mark each aspect ratio that is suspected as a sample to be verified. Step 6: Perform modal analysis on the mode shapes corresponding to the main peak and adjacent peaks of the complex impedance of each sample to be verified, and calculate the proportion of thickness-direction modes for each sample to be verified. ; Step 7: Combine the preliminary judgment results of each sample to be verified with the corresponding thickness direction mode proportions. The aspect ratio range of the modal coupling anomaly was determined, and the optimal aspect ratio design range of the piezoelectric ceramic column was obtained by screening.

[0010] As an improvement to the above technical solution, in step 1, the finite element simulation model includes: piezoelectric ceramic pillars arranged along the thickness direction, a polymer matrix filling the gaps between the piezoelectric ceramic pillars, an upper electrode disposed on the upper surface of the composite material, and a lower electrode disposed on the lower surface of the composite material.

[0011] As an improvement to the above technical solution, in step 2, the volume fraction of the piezoelectric ceramic ranges from 40% to 70%. The aspect ratio of the piezoelectric ceramic column for: ; in, The height of the piezoelectric ceramic column. The width of the piezoelectric ceramic column.

[0012] As an improvement to the above technical solution, in step 4, the complex impedance spectrum characteristics include: the position of the main peak of the complex impedance response curve, the number of stray peaks, and the distribution of additional peaks near the main peak. The effective electromechanical coupling coefficient for: ; in, This is the resonant frequency corresponding to the complex impedance response curve. This is the anti-resonant frequency corresponding to the complex impedance response curve.

[0013] As an improvement to the above technical solution, in the preliminary judgment of step 5, the aspect ratio that meets any of the following judgment conditions is judged as having suspected modal coupling and marked as a sample to be verified: The effective electromechanical coupling coefficient corresponding to the current aspect ratio It is a local maximum, and there is at least one additional small peak near the main peak of the complex impedance response curve; The number of stray peaks corresponding to the current aspect ratio is greater than the number of stray peaks corresponding to the adjacent higher aspect ratio; The frequency interval between the main peak and the additional small peak of the complex impedance response curve is less than the preset interval threshold.

[0014] As an improvement to the above technical solution, in step 6, the proportion of thickness-direction modes... for: ; in, Let x be the displacement component in the x-direction of the piezoelectric ceramic column vibration. Let y be the displacement component in the vibration direction of the piezoelectric ceramic column. The z-direction displacement component of the piezoelectric ceramic column vibration; The solution domain for the vibration of the piezoelectric ceramic column; ρ For the density of composite materials As an improvement to the above technical solution, in step 7, a preliminary judgment is made regarding the presence of modal coupling and the proportion of modes in the thickness direction. Each aspect ratio below the preset modal proportion threshold is classified into the modal coupling abnormal aspect ratio range. Each aspect ratio not located in the modal coupling abnormal aspect ratio range is taken as the preferred aspect ratio region, thus obtaining the preferred aspect ratio design range of the piezoelectric ceramic column.

[0015] As an improvement to the above technical solution, the method further includes: Step 8: Within the preferred aspect ratio design range, the aspect ratio that meets the following screening conditions is taken as the optimal aspect ratio: The number of stray peaks corresponding to the aspect ratio is less than or equal to 1; The proportion of thickness-direction modes corresponding to aspect ratio Greater than 0 and less than 1; The main peak frequency corresponding to the aspect ratio meets the target operating frequency requirement, and Effective electromechanical coupling coefficient corresponding to aspect ratio Enter a stable platform.

[0016] To achieve another objective of this application, this application also provides a 1-3 type piezoelectric composite material aspect ratio optimization system for implementing the above-mentioned 1-3 type piezoelectric composite material aspect ratio optimization method, comprising: The simulation module is used to establish finite element simulation models of piezoelectric composite materials of types 1-3. The parameter configuration module is used to keep the volume fraction of piezoelectric ceramics constant and set multiple sets of different aspect ratios for piezoelectric ceramic columns. The frequency domain electromechanical coupling analysis module is used to perform frequency domain electromechanical coupling analysis on finite element models corresponding to various aspect ratios, and obtain the complex impedance response curves as a function of frequency under various aspect ratios. The parameter calculation and curve construction module is used to extract the corresponding complex impedance spectrum features from each complex impedance response curve and calculate the effective electromechanical coupling coefficient corresponding to each aspect ratio. Establish the relationship curve between the effective electromechanical coupling coefficient and the aspect ratio; The anomaly screening module is used to locate local abnormal peaks based on the relationship curve of the effective electromechanical coupling coefficient with aspect ratio; combined with the complex impedance spectrum characteristics corresponding to each aspect ratio, it preliminarily judges whether each local abnormal peak is suspected of modal coupling, and marks each aspect ratio that is suspected as a sample to be verified. The modal proportion calculation module is used to perform modal analysis on the mode shapes corresponding to the main peak and adjacent peaks of the complex impedance of each sample to be verified, and to calculate the proportion of thickness-direction modes for each sample to be verified. ;and The interval determination and filtering module is used to combine the preliminary judgment results of each sample to be verified with the corresponding thickness direction mode proportion. The aspect ratio range of the modal coupling anomaly was determined, and the optimal aspect ratio design range of the piezoelectric ceramic column was obtained by screening.

[0017] To achieve another objective of this application, this application also provides a type 1-3 piezoelectric composite material, comprising: piezoelectric ceramic pillars arranged along the thickness direction, a polymer matrix filling the gaps between the piezoelectric ceramic pillars, an upper electrode disposed on the upper surface of the composite material, and a lower electrode disposed on the lower surface of the composite material; wherein the aspect ratio of the piezoelectric ceramic pillars is determined by the aspect ratio optimization method of the type 1-3 piezoelectric composite material described above.

[0018] To achieve another objective of this application, this application also provides an underwater acoustic transducer comprising the aforementioned type 1-3 piezoelectric composite material.

[0019] The advantages of this application are: 1. By combining complex impedance spectroscopy and thickness-direction mode ratio analysis, the source of abnormal peak values ​​in electromechanical coupling coefficient can be accurately identified, avoiding misjudging local modal coupling as intrinsic performance improvement; 2. By adopting a multi-index comprehensive screening mechanism, the optimal aspect ratio design range corresponding to stable thickness modes with few stray peaks and high modal purity can be located; 3. Effectively reduces parasitic resonance interference in the operating frequency band of underwater acoustic transducers and improves frequency response stability; 4. It is compatible with composite materials of various volume fractions, and can provide quantitative design criteria for underwater acoustic transducers, ultrasonic probes and other applications. Attached Figure Description

[0020] Figure 1 This is a graph showing the trend of effective electromechanical coupling coefficient as aspect ratio increases when the volume fraction is 55%. Figure 2 This is a graph showing the variation of complex impedance with increasing frequency when the volume fraction is 55% and the aspect ratio is 0-4. Figure 3 This is a schematic diagram of a unit cell model of a piezoelectric composite material. Figure 4 The flowchart shows the aspect ratio optimization method for type 1-3 piezoelectric composite materials provided by the present invention. Detailed Implementation

[0021] The technical solutions provided in this application are further illustrated below with reference to the embodiments.

[0022] The aspect ratio optimization method for type 1-3 piezoelectric composite materials based on complex impedance spectroscopy and electromechanical coupling anomaly identification provided in this embodiment includes the following steps: S1: Establish a finite element model of type 1-3 piezoelectric composite material. The model includes piezoelectric ceramic pillars arranged along the thickness direction, a polymer matrix filling the gaps between the piezoelectric ceramic pillars, and an upper electrode and a lower electrode respectively disposed on the upper and lower surfaces of the composite material. S2: Set the volume fraction of piezoelectric ceramic to 55%, and change the aspect ratio of the piezoelectric ceramic column (0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4) while keeping the volume fraction constant. S3: Perform frequency domain electromechanical coupling analysis on models with different aspect ratios to obtain the response curves of complex impedance as a function of frequency; S4: Extract the position of the main peak, the number of stray peaks, and the distribution of additional peaks near the main peak based on the complex impedance curve; S5: Calculate the effective electromechanical coupling coefficient under different aspect ratios. : (1) in, The resonant frequency, It is the anti-resonant frequency; S6: According to Local abnormal peaks are identified by curves showing changes in aspect ratio, and the complex impedance spectrum is used to determine whether the abnormal peaks are caused by local modal coupling or peak misidentification. S7: The mode shapes at the frequencies corresponding to the main peak and its adjacent smaller peaks are analyzed. To quantitatively characterize the proportion of thickness-direction vibration in the total vibration, this invention defines a thickness-direction modal proportion index to characterize the relative contribution of thickness-direction displacement to the total displacement response. For composite material models, considering the density differences of different material phases, a density-weighted form is introduced. The thickness-direction modal proportion is calculated. The formula is: (2) in, , , These are the displacement components in the three directions of the piezoelectric ceramic column vibration; The solution domain for the vibration of the piezoelectric ceramic column; ρ The density of the composite material. When When the value is close to 1, it indicates that the structural response is mainly dominated by vibration in the thickness direction; when... A significant decrease indicates that transverse modes, shear modes, or local modes are involved in the enhancement.

[0023] S8: When a certain aspect ratio corresponds to When a local maximum occurs, but the complex impedance curve contains additional small peaks, the number of stray peaks exceeds the threshold, or the proportion of thickness-direction modes is lower than the threshold, the aspect ratio is determined to be an abnormal modal coupling region, rather than an optimal design region. S9: Features fewer stray peaks, a higher proportion of thickness modes, and a main peak frequency that meets the target operating frequency requirements. The aspect ratio range that enters the stable platform is determined as the preferred design range. In this embodiment, the screening criteria include: The number of stray peaks corresponding to the aspect ratio is less than or equal to 1; The proportion of thickness-direction modes corresponding to aspect ratio Greater than 0 and less than 1; The main peak frequency corresponding to the aspect ratio meets the target operating frequency requirement, and Effective electromechanical coupling coefficient corresponding to aspect ratio Enter a stable platform.

[0024] Example 1: Aspect Ratio Optimization of Type 1-3 Piezoelectric Composite Material with a Volume Fraction of 55% This embodiment uses PZT 1-3 type piezoelectric composite material as the object, wherein the piezoelectric ceramic pillars are polarized along the thickness direction, the polymer is filled between the ceramic pillars, and electrodes are set on the upper and lower surfaces. The volume fraction of piezoelectric ceramic is set to 55%. The aspect ratio is defined as: (3) in, The height of the piezoelectric ceramic column. The width of the piezoelectric ceramic column.

[0025] While keeping the volume fraction constant at 55%, select respectively Aspect ratios of 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, and 5 were used to establish corresponding COMSOL simulation models, which were then subjected to frequency domain analysis. By applying a unit AC voltage between the upper and lower electrodes, the current response at different frequencies was calculated to obtain the complex impedance. : (4) in, For complex impedance, For voltage, It represents electric current.

[0026] Extract the resonant frequency from the complex impedance curves under different aspect ratios. and anti-resonant frequency Further calculation of the effective electromechanical coupling coefficient Simulation results show that as the aspect ratio increases from 0.5 to 1.5, the effective electromechanical coupling coefficient continuously increases, and... The effective electromechanical coupling coefficient reaches its maximum value of approximately 0.86 near the maximum. Subsequently, as the aspect ratio increases to 2, the effective electromechanical coupling coefficient decreases significantly. Afterward, with further increases in aspect ratio, the effective electromechanical coupling coefficient slowly increases and gradually stabilizes at around 0.67.

[0027] Meanwhile, the complex impedance spectroscopy results show that when to At this point, the impedance curve exhibits noticeable stray peaks, and the number of stray peaks gradually decreases as the aspect ratio increases. When At this point, the impedance curve shows a main peak and an additional small peak, indicating that local modes still participate near the main thickness mode. Afterward, stray peaks decreased significantly, and the impedance curve gradually showed characteristics of a single main peak.

[0028] Therefore, although in this embodiment The corresponding effective electromechanical coupling coefficient is the largest, but considering the complex impedance spectrum, this peak value may be affected by local modal coupling and should not be directly used as the optimal aspect ratio. In contrast, Subsequently, the structural vibrations become closer to the stable thickness mode. It has also gradually entered a stable range, making it more suitable as a reference for the structural design of underwater acoustic transducers.

[0029] Example 2: Method for Identifying Abnormal Coupling Points In another embodiment, the present invention may further include an abnormal coupling point identification criterion. For a given aspect ratio... If any of the following conditions are met, the aspect ratio is determined to be in a modal coupling anomalous region: 1. The aspect ratio corresponding to this It is a local maximum, but there is at least one additional small peak near the main peak in the complex impedance curve; 2. The number of stray peaks at this aspect ratio is greater than the number of stray peaks at adjacent higher aspect ratios; 3. The frequency interval between the main peak and the additional smaller peaks is small, which may indicate modal coupling; 4. Proportion of modes in the thickness direction Below the preset threshold; 5. The main peak corresponds to a mode shape in which there is obvious lateral displacement, shear displacement, or local column vibration.

[0030] Under the above criteria, Although it has a high However, due to the presence of additional smaller peaks near its main peak, this region can be marked as a modal coupling anomaly region. This avoids directly using locally artificial peaks in transducer design. As a basis for optimization.

[0031] Example 3: Application of underwater acoustic transducers After determining the preferred aspect ratio using the above method, piezoelectric composite materials of types 1-3 can be used for underwater acoustic transducer elements. The underwater acoustic transducer may include a piezoelectric composite material layer, a backing layer, a matching layer, an electrode layer, and a water-loaded medium. In the design process, the aspect ratio of the piezoelectric composite material is first screened using the method of this invention; then, the backing layer and matching layer are jointly designed based on the target operating frequency, acoustic impedance matching requirements, bandwidth requirements, and transducer size constraints. Because there are fewer stray peaks in the preferred aspect ratio range, the transducer can achieve a more stable impedance response and more reliable electromechanical conversion performance within the operating frequency band.

[0032] As can be seen from the above detailed description of this application, this application has at least the following advantages: 1. It can identify the source of abnormal peak values ​​in the effective electromechanical coupling coefficient.

[0033] In type 1-3 piezoelectric composite materials with a volume fraction of 55%, the effective electromechanical coupling coefficient increases rapidly as the aspect ratio increases from 0.5 to 1.5, and then... It reaches its maximum value nearby; then in The amplitude decreases near the surface, then slowly increases with further increases in aspect ratio and eventually stabilizes. This invention determines this through complex impedance spectroscopy and modal analysis. To determine whether the high value at a certain point is caused by the coupling between the principal thickness mode and the local mode, thereby avoiding misjudging the abnormal peak value as the optimal intrinsic properties of the material.

[0034] 2. It can improve the reliability of aspect ratio screening.

[0035] Traditional methods may only be based on The maximum value is selected based on the aspect ratio. This invention also considers the number of stray peaks in the complex impedance curve, the additional peaks near the main peak, the frequency shift law of the main peak, and the proportion of modes in the thickness direction. Therefore, it can select an aspect ratio range that is more suitable for stable thickness vibration operation.

[0036] 3. It can reduce the influence of parasitic modes in the operating frequency band of underwater acoustic transducers.

[0037] When the aspect ratio is low, multiple stray peaks appear in the complex impedance curve, indicating significant involvement of transverse modes, shear modes, and local column vibration modes. This invention, by identifying these stray peaks, avoids selecting structural parameters with strong parasitic modes, thereby improving the frequency response stability of the transducer.

[0038] 4. It can provide quantitative criteria for the material and structural design of underwater acoustic transducers.

[0039] This invention not only provides an effective electromechanical coupling coefficient, but also introduces the number of stray peaks, peak position variation, and thickness direction mode ratio as comprehensive evaluation indicators, transforming the design of type 1-3 piezoelectric composite materials from single parameter optimization to multi-indicator mode screening.

[0040] 5. Applicable to different volume fractions and different transducer application scenarios.

[0041] Although the specific embodiment uses a volume fraction of 55% as an example, the method can be extended to 40%–70% or other volume fraction ranges, and can be used for underwater acoustic transducers, ultrasonic transducers and related acoustic measurement and control systems.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for optimizing the aspect ratio of type 1-3 piezoelectric composite materials, comprising the following steps: Step 1: Establish finite element simulation models of type 1-3 piezoelectric composite materials; Step 2: Keep the volume fraction of piezoelectric ceramics constant, and set multiple sets of different aspect ratios for the piezoelectric ceramic columns; Step 3: Perform frequency domain electromechanical coupling analysis on the finite element models corresponding to each aspect ratio to obtain the complex impedance response curves as a function of frequency for each aspect ratio; Step 4: Extract the corresponding complex impedance spectrum features from each complex impedance response curve, and calculate the effective electromechanical coupling coefficient corresponding to each aspect ratio. Establish the relationship curve between the effective electromechanical coupling coefficient and the aspect ratio; Step 5: Based on the relationship curve of effective electromechanical coupling coefficient with aspect ratio, locate each local abnormal peak; combine the complex impedance spectrum characteristics corresponding to each aspect ratio to preliminarily determine whether each local abnormal peak is suspected of modal coupling, and mark each aspect ratio that is suspected as a sample to be verified. Step 6: Perform modal analysis on the mode shapes corresponding to the main peak and adjacent peaks of the complex impedance of each sample to be verified, and calculate the proportion of thickness-direction modes for each sample to be verified. ; Step 7: Combine the preliminary judgment results of each sample to be verified with the corresponding thickness direction mode proportions. The aspect ratio range of the modal coupling anomaly was determined, and the optimal aspect ratio design range of the piezoelectric ceramic column was obtained by screening.

2. The aspect ratio optimization method for type 1-3 piezoelectric composite materials according to claim 1, characterized in that, In step 1, the finite element simulation model includes: piezoelectric ceramic pillars arranged along the thickness direction, a polymer matrix filling the gaps between the piezoelectric ceramic pillars, an upper electrode disposed on the upper surface of the composite material, and a lower electrode disposed on the lower surface of the composite material.

3. The aspect ratio optimization method for type 1-3 piezoelectric composite materials according to claim 1, characterized in that, In step 2, the volume fraction of the piezoelectric ceramic ranges from 40% to 70%. The aspect ratio of the piezoelectric ceramic column for: ； in, The height of the piezoelectric ceramic column. The width of the piezoelectric ceramic column.

4. The aspect ratio optimization method for type 1-3 piezoelectric composite materials according to claim 1, characterized in that, In step 4, the complex impedance spectrum characteristics include: the position of the main peak of the complex impedance response curve, the number of stray peaks, and the distribution of additional peaks near the main peak. The effective electromechanical coupling coefficient for: ； in, This is the resonant frequency corresponding to the complex impedance response curve. This is the anti-resonant frequency corresponding to the complex impedance response curve.

5. The aspect ratio optimization method for type 1-3 piezoelectric composite materials according to claim 4, characterized in that, In the preliminary judgment of step 5, the aspect ratio that meets any of the following judgment conditions is judged as having suspected modal coupling and marked as a sample to be verified: The effective electromechanical coupling coefficient corresponding to the current aspect ratio It is a local maximum, and there is at least one additional small peak near the main peak of the complex impedance response curve; The number of stray peaks corresponding to the current aspect ratio is greater than the number of stray peaks corresponding to the adjacent higher aspect ratio; The frequency interval between the main peak and the additional small peak of the complex impedance response curve is less than the preset interval threshold.

6. The aspect ratio optimization method for type 1-3 piezoelectric composite materials according to claim 1, characterized in that, In step 6, the proportion of thickness direction modes for: ； in, Let x be the displacement component in the x-direction of the piezoelectric ceramic column vibration. Let y be the displacement component in the vibration direction of the piezoelectric ceramic column. The z-direction displacement component of the piezoelectric ceramic column vibration; The solution domain for the vibration of the piezoelectric ceramic column; ρ This represents the density of the composite material.

7. The aspect ratio optimization method for type 1-3 piezoelectric composite materials according to claim 1, characterized in that, In step 7, a preliminary assessment will be made regarding the presence of modal coupling and the proportion of modes in the thickness direction. Each aspect ratio below the preset modal proportion threshold is classified into the modal coupling abnormal aspect ratio range. Each aspect ratio not located in the modal coupling abnormal aspect ratio range is taken as the preferred aspect ratio region, thus obtaining the preferred aspect ratio design range of the piezoelectric ceramic column. The process also includes step 8: Within the preferred aspect ratio design range, the aspect ratio that meets the following screening criteria is taken as the optimal aspect ratio: The number of stray peaks corresponding to the aspect ratio is less than or equal to 1; The proportion of thickness-direction modes corresponding to aspect ratio Greater than 0 and less than 1; The main peak frequency corresponding to the aspect ratio meets the target operating frequency requirement, and Effective electromechanical coupling coefficient corresponding to aspect ratio Enter a stable platform.

8. A height-to-width ratio optimization system for type 1-3 piezoelectric composite materials, used to implement the height-to-width ratio optimization method for type 1-3 piezoelectric composite materials according to any one of claims 1-7, comprising: The simulation module is used to establish finite element simulation models of piezoelectric composite materials of types 1-3. The parameter configuration module is used to keep the volume fraction of piezoelectric ceramics constant and set multiple sets of different aspect ratios for piezoelectric ceramic columns. The frequency domain electromechanical coupling analysis module is used to perform frequency domain electromechanical coupling analysis on finite element models corresponding to various aspect ratios, and obtain the complex impedance response curves as a function of frequency under various aspect ratios. The parameter calculation and curve construction module is used to extract the corresponding complex impedance spectrum features from each complex impedance response curve and calculate the effective electromechanical coupling coefficient corresponding to each aspect ratio. Establish the relationship curve between the effective electromechanical coupling coefficient and the aspect ratio; The anomaly screening module is used to locate local abnormal peaks based on the relationship curve of the effective electromechanical coupling coefficient with aspect ratio; combined with the complex impedance spectrum characteristics corresponding to each aspect ratio, it preliminarily judges whether each local abnormal peak is suspected of modal coupling, and marks each aspect ratio that is suspected as a sample to be verified. The modal proportion calculation module is used to perform modal analysis on the mode shapes corresponding to the main peak and adjacent peaks of the complex impedance of each sample to be verified, and to calculate the proportion of thickness-direction modes for each sample to be verified. ; and The interval determination and filtering module is used to combine the preliminary judgment results of each sample to be verified with the corresponding thickness direction mode proportion. The aspect ratio range of the modal coupling anomaly was determined, and the optimal aspect ratio design range of the piezoelectric ceramic column was obtained by screening.

9. A type 1-3 piezoelectric composite material, characterized in that, include: The composite material comprises piezoelectric ceramic pillars arranged along the thickness direction, a polymer matrix filling the gaps between the piezoelectric ceramic pillars, an upper electrode disposed on the upper surface of the composite material, and a lower electrode disposed on the lower surface of the composite material; wherein the aspect ratio of the piezoelectric ceramic pillars is determined by the aspect ratio optimization method of type 1-3 piezoelectric composite material according to any one of claims 1-7.

10. A hydroacoustic transducer, characterized in that, Including the type 1-3 piezoelectric composite materials as described in claim 9.

Images