General detection method and device for piezoelectric property of piezoelectric ceramics of underwater acoustic transducer

Abstract

The invention discloses a universal detection method for the piezoelectric property of piezoelectric ceramics of an underwater acoustic transducer, and the method comprises the steps: installing the piezoelectric ceramics of a to-be-detected transducer in a structural member, and adjusting the state of a prestress; fixing the tested transducer and the standard transducer at symmetrical positions, and outputting vibration energy to the tested transducer and the standard transducer by using a symmetrical vibration tool; collecting and monitoring output signals of the two paths of transducers, adjusting various parameters of the vibration tool to enable the amplitudes of the two paths of signals to be stabilized in a certain range, and recording the output amplitude of the standard transducer at the moment as A1; calculating the ratio of the amplitudes of the two paths of signals, recording the ratio as K1 and K as a piezoelectric performance scalar value of the piezoelectric ceramic of the transducer to be measured in an assembly state, and fixing a measurement element set M at the moment; the method comprises the following steps: replacing a tested transducer, obtaining a K2 value of a new tested transducer under the condition of a measurement element set M, carrying out batch testing to obtain a Kn sequence, and keeping the sequence to fluctuate within a certain range so as to control the consistency of core performance indexes of a finished transducer.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric ceramic detection, and particularly relates to a general detection method and device for the piezoelectric performance of piezoelectric ceramics of an underwater acoustic transducer. Background Art

[0002] An underwater acoustic transducer based on piezoelectric ceramics generally consists of a structural member, piezoelectric ceramics, a preamplifier circuit, and a vulcanized layer. It is mainly used for underwater acoustic signal acquisition (passive underwater acoustic transducer) and underwater acoustic signal transmission (active underwater acoustic transducer). The structural member in the underwater acoustic transducer is used to clamp and install the piezoelectric ceramics, and is also the attachment surface of the vulcanized layer. The preamplifier circuit is used for signal amplification and impedance matching. The vulcanized layer is generally formed by a polyurethane vulcanization process, and is used to form an isolation layer between the piezoelectric ceramics and the acoustic medium (water), and at the same time plays a certain protective role for the fragile ceramics. As Figure 1 shown, it is a schematic diagram of the internal structure of a typical underwater acoustic transducer.

[0003] As the core component of the transducer, piezoelectric ceramics can convert the mechanical energy of acoustic field vibration and the electrical energy of the electric field with each other. As a receiving transducer, piezoelectric ceramics convert the mechanical energy of acoustic wave vibration into weak electrical signals. As a transmitting transducer, piezoelectric ceramics convert electrical signals into mechanical vibrations and emit the energy in the form of acoustic waves. The piezoelectric performance of piezoelectric ceramics directly determines the key performance indicators of the transducer, such as sensitivity, transmission response, directivity, etc. Therefore, in the design and manufacturing process of underwater acoustic transducers, how to achieve the best piezoelectric performance of piezoelectric ceramics is a core and key issue.

[0004] The piezoelectric performance of piezoelectric ceramics is affected by various factors, and the prestress adjustment of piezoelectric ceramics is the most critical in engineering practice. Due to the limitations of the use scenario and manufacturing process of underwater acoustic transducers, the core indicators such as the sensitivity and directivity of underwater acoustic transducers can only be quantitatively evaluated through professional tests underwater, so the transducer can only be tested for indicators after vulcanization and forming. However, the prestress of piezoelectric ceramics cannot be adjusted for the transducer after vulcanization and forming. If defects in the previous assembly process cause prestress imbalance, there is a certain probability that the core indicators such as the sensitivity and directivity of the transducer will exceed the standard. Therefore, how to quantitatively detect the piezoelectric performance of piezoelectric ceramics after the piezoelectric ceramics are assembled and before the transducer is vulcanized and formed is the key to improving the quality of the transducer. As Figure 2 shown, it is a schematic diagram of the prestress force of piezoelectric ceramics of a typical underwater acoustic transducer. During the assembly process of the transducer, by adjusting the compression nut, a downward prestress is applied to the piezoelectric ceramic ring below. The magnitude and balance of this prestress directly affect the key performance indicators of the transducer after vulcanization and forming. If the piezoelectric performance under prestress can be measured and evaluated before vulcanization and forming, the qualified rate of the transducer can be effectively improved. Summary of the Invention

[0005] The object of the present invention is to provide a general detection method for the piezoelectric properties of piezoelectric ceramics of underwater acoustic transducers in order to solve the above problems and improve the qualification rate of transducers.

[0006] To achieve the above object, the present invention provides the following technical solution: A general detection method for the piezoelectric properties of piezoelectric ceramics of underwater acoustic transducers, including: S1. Install the piezoelectric ceramic of the transducer under test into the structural member and adjust the prestress state; if the prestress state of the piezoelectric ceramic is the same as that before vulcanization and sealing, no additional adjustment is required.

[0007] S2. Fix the transducer under test and the standard transducer at symmetric positions, and use a symmetric vibration tooling to output vibration energy to both of them simultaneously; that is, apply equal energy input to the transducer under test and the standard transducer simultaneously to facilitate comparison during subsequent testing. The standard transducer refers to a transducer with stable frequency response tested by a professional metrology institution.

[0008] S3. Collect and monitor the output signals of the two transducers simultaneously, and adjust the various parameters of the vibration tooling to make the amplitudes of the two signals stable within a certain range, and record the output amplitude of the standard transducer at this time, denoted as A1; the various parameters include but are not limited to distance, position, frequency, amplitude, etc., and the purpose is to make the two signals collected complete and stable.

[0009] S4. Calculate the ratio of the amplitudes of the two signals, denoted as K1. The K value is the piezoelectric performance scalar value of the piezoelectric ceramic of the transducer under test in the assembled state, and at the same time fix the measurement element set M at this time; the measurement element set M includes the installation position of the transducer under test, the installation position of the standard transducer, and the output parameters of the vibration tooling.

[0010] S41: Calculate by intercepting the amplitude average value of the same time window of the two signals. The time window should be selected during the steady-state process of the two signals, and non-steady-state signals should not be included in the time window; S42: Fix the measurement element set M at this time. This step should fully consider various factors affecting the vibration energy output. Generally, it necessarily includes factors such as the installation position of the product under test, the installation position of the standard transducer, and the position of the vibration tooling.

[0011] S5. Replace the transducer under test, and under the condition of the measurement element set M, obtain the K2 value of the new transducer under test, and so on. Batch testing obtains a K n sequence, and this sequence fluctuates within a certain range, so as to control the consistency of the core performance indicators of the finished transducers.

[0012] In this step, the difference between the output value of the standard transducer and the A1 value should also be observed. When the difference is greater than the preset threshold, it indicates that a non-negligible shift has occurred in the measurement element set M, and the test elements should be adjusted in a timely manner to make the output value of the standard transducer return to the A1 value.

[0013] A general detection device for the piezoelectric properties of piezoelectric ceramics of an underwater acoustic transducer, comprising: Mounting brackets, symmetrically arranged, for mounting the transducer under test and the standard transducer; A vibration tooling, arranged on one side of the mounting bracket, for simultaneously outputting vibration energy to the transducer under test and the standard transducer; A vibration motor, connected to the vibration tooling, and the vibration motor is connected with a vibration control box, A signal acquisition system, connected to the transducer under test and the standard transducer through a connection cable, intercepting the amplitudes of the two signals through upper computer software, and performing ratio comparison.

[0014] An adjustment mechanism is provided on the mounting bracket for adjusting the mounting positions of the transducer under test and the standard transducer.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: It can adjust the piezoelectric properties of the piezoelectric ceramics of the transducer to the optimal state before vulcanization and molding; For batch samples, it can effectively control the piezoelectric properties of the piezoelectric ceramics within a certain range, so as to ensure the consistency of the key performance indicators of the transducer; It can conveniently, quickly and quantitatively study the piezoelectric properties of piezoelectric ceramics under different prestress conditions, providing new ideas and means for the design of various transducers and the selection of piezoelectric ceramics. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic diagram of the internal structure of a typical underwater acoustic transducer of the present invention; Figure 2 It is a schematic diagram of the prestress force on the piezoelectric ceramics of a typical underwater acoustic transducer of the present invention; Figure 3 It is a schematic diagram of the steady-state selection of two signals of the present invention; Figure 4 It is a schematic diagram of uniformly selecting test points at 360° horizontally for the circular ring piezoelectric ceramics of the present invention; Figure 5 Schematic diagram of the detection device structure of the present invention; Figure 6 Schematic diagram of the working process of Embodiment 1 of the present invention; Figure 7 Schematic diagram of the working process of Embodiment 2 of the present invention.

[0018] Explanation of reference numerals in the drawings: 1. Installation bracket; 2. Vibration tooling; 3. Vibration control box; 4. Vibration motor; 5. Connecting cable; 6. Signal acquisition system; 7. Adjusting mechanism. Specific implementation manners

[0019] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without making creative efforts fall within the scope protected by the present invention.

[0020] The present invention utilizes the basic principle of piezoelectric ceramic energy conversion, adopts a symmetric installation structure, inputs mechanical energy into the product under test and the standard transducer simultaneously and collects electrical signals (outputs), calculates the quantitative value of the piezoelectric performance of the product under test by comparing the energy amplitudes of the two collected signals, thereby evaluating the prestress condition of the piezoelectric ceramic of the transducer under test, and continuously adjusts according to the evaluation result to make the piezoelectric performance of the piezoelectric ceramic reach the expected range.

[0021] The present embodiment provides the following technical solution, that is, a general detection method for the piezoelectric performance of a piezoelectric ceramic of an underwater acoustic transducer, including the following steps: S1: Install the piezoelectric ceramic of the transducer under test into the structural member and adjust its prestress state; For piezoelectric ceramics with different structures and installation methods, it has two levels of meaning. One refers to the prestress that is not intentionally applied. A common situation is the natural stress points formed by the attachment and connection of the piezoelectric ceramic and the structural member. The other refers to the intentionally applied prestress, mainly based on the basic principle of the piezoelectric ceramic to apply prestress axially or radially on its radiation surface to achieve specific piezoelectric performance. Common situations include compression bolts, baffles, etc.

[0022] S2: Fix the transducer under test and the standard transducer at symmetric positions simultaneously, and use the symmetric vibration tooling to output vibration energy to both of them simultaneously; Highlighting the "symmetric" position is for the vibration tooling to input equal amount and same frequency vibration to the two transducers simultaneously. The symmetric position can be changed according to the specific size and structure of the transducer. The so-called "standard transducer" refers to a transducer with stable frequency response tested by a professional metrology institution.

[0023] S3: Simultaneously collect and monitor the output signals of the two transducers. When necessary, adjust the parameters of the vibration tooling to make the amplitudes of the two signals stable within a certain range. Record the output amplitude of the standard transducer at this time, denoted as A1; The so-called "parameters of the tooling" include, but are not limited to, distance, position, frequency, amplitude, etc., with the aim of making the two collected signals complete and stable.

[0024] S4: Calculate the ratio of the amplitudes of the two signals, denoted as K1. The K value is the piezoelectric performance scalar value of the piezoelectric ceramic of the transducer under test in the assembled state. At the same time, fix the measurement element set M at this time, including the installation position of the product under test, the installation position of the standard transducer, the output parameters of the vibration tooling, etc.; S41: Calculate the ratio of the amplitudes of the two signals, denoted as K1. Considering signal fluctuations, the average amplitude values of the two signals in the same time window should be intercepted for calculation. The time window should be selected during the steady-state process of the two signals, and non-steady-state signals should not be included in the time window, as shown below Figure 3 as follows.

[0025] S42: Fix the measurement element set M at this time. This step should fully consider all factors affecting the vibration energy output. Generally, it necessarily includes factors such as the installation position of the product under test, the installation position of the standard transducer, and the position of the vibration tooling.

[0026] S5: Replace the product under test and obtain the K2 value of the new product under test under the condition of the measurement element set M. By analogy, for batch testing, a K n sequence can be obtained, and this sequence fluctuates within a certain range, thereby controlling the consistency of the core performance indicators of the finished transducer.

[0027] In step S5, the difference between the output value of the standard transducer and the A1 value should also be observed. When the difference is greater than the preset threshold, it indicates that the measurement element set M has an unnegligible deviation, and the test elements should be adjusted in a timely manner to make the output value of the standard transducer return to the A1 value. The "replace the product under test" in step S5 can also refer to detecting different positions of the same piezoelectric ceramic. For example, when evaluating the piezoelectric performance of a circular piezoelectric ceramic at 360° horizontally, points can be evenly taken on the circumference, as Figure 4 shown.

[0028] such as Figure 5As shown, the present invention also provides a general detection device for the piezoelectric performance of a piezoelectric ceramic of an underwater acoustic transducer using the method described above. The mounting bracket 1 can facilitate the installation and fixation of the tested product and the standard transducer, so that the spatial positions of the two are equidistant from the contacts of the vibration tooling. The vibration tooling 2 has symmetrical vibration arms and contacts, and can simultaneously output vibration energy to the tested product and the standard transducer; the length of the vibration arm can be fine-tuned, and the vibration control box 3 can adjust the output power of the vibration motor 4 to achieve the parameter adjustment in step S3, so that the amplitude of the two-way signal is stable within a certain range. The output signals of the two-way transducer enter the signal acquisition system 6 respectively through the connecting cable 5. The system intercepts the amplitude of the two-way signal through the upper computer software, and performs a ratio, and automatically calculates the A value and K value in steps S3 and S4. At the same time, the system can also monitor the pre-set A value and K value fluctuation thresholds, and a system prompt will be given once the threshold is exceeded. The adjustment mechanism 7 distributed throughout the device and the output power of the vibration motor 4 jointly solidify the measurement element set M in each state.

[0029] Example 1 like Figure 6 As shown, an example of piezoelectric performance testing and prestress adjustment of piezoelectric ceramic rings in the batch manufacturing process of underwater acoustic transducers in this embodiment is shown, including the following steps: S1: Install the piezoelectric ceramic ring of the transducer to be tested into the transducer structure and adjust its prestress state; S2: The transducer under test and the standard transducer are fixed at symmetrical positions at the same time, and the symmetrical vibration fixture is used to output vibration energy to both of them at the same time; S3: Collect and monitor the output signals of the two transducers at the same time. If necessary, adjust the parameters of the vibration tooling to stabilize the amplitudes of the two signals within a certain range. Record the output amplitude of the standard transducer at this time, which is recorded as A1; S4: Calculate the ratio of the amplitudes of the two signals, recorded as K1. At the same time, fix the measurement element set M at this time, such as the installation position of the measured product, the installation position of the standard transducer, the output parameters of the vibration tooling, etc.; S5: Replace the tested product and obtain the K2 value of the new tested product under the condition of the measurement element set M. Similarly, a K2 value can be obtained for batch testing. n The sequence is kept within a certain range, thereby controlling the consistency of the core performance indicators of the finished transducer.

[0030] Example 2 like Figure 7 As shown, the present invention shows that in scientific research, the piezoelectric performance of a longitudinal vibration transducer under different prestresses is studied, including the following steps: S1: Install the piezoelectric disc of the longitudinal vibration transducer to be tested into the transducer structure and adjust its prestress state; S2: Fix the product under test and the standard transducer at symmetric positions simultaneously, and use the symmetric vibration tooling to output vibration energy to both of them simultaneously. S3: Collect and monitor the output signals of the two transducers simultaneously. When necessary, adjust the parameters of the vibration tooling so that the amplitudes of the two signals are stabilized within a certain range. Record the output amplitude of the standard transducer at this time, denoted as A1. S4: Calculate the ratio of the amplitudes of the two signals, denoted as K1. Fix the measurement element set M at this time, such as the installation position of the product under test, the installation position of the standard transducer, the output parameters of the vibration tooling, etc. S5: Readjust the prestress T2 of the transducer under test. Under the condition of the measurement element set M, obtain the K2 value in the new state. Record the corresponding relationship between each prestress T n and K n value. By analogy, a K n sequence under different prestresses can be obtained, so as to study the direct relationship between the prestress and the piezoelectric properties of the piezoelectric ceramics of this type of longitudinal vibration transducer.

[0031] Within the technical scope disclosed by the present invention, changes or substitutions that can be easily conceived should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the said claims.

Claims

1. A general detection method for the piezoelectric properties of piezoelectric ceramics of an underwater acoustic transducer, characterized in that, include: S1. Install the piezoelectric ceramic of the transducer to be tested into the structural component and adjust the prestress state; S2, fix the transducer under test and the standard transducer in symmetrical positions, and use a symmetrical vibration tooling to output vibration energy to both at the same time; S3, simultaneously collect and monitor the output signals of the two transducers, adjust various parameters of the vibration tooling, so that the amplitudes of the two signals are stable within a certain range, and record the output amplitude of the standard transducer at this time, which is recorded as A1; S4, calculating the ratio of the amplitudes of the two signals, recorded as K1, where the K value is the scalar value of the piezoelectric performance of the piezoelectric ceramic of the transducer under test in the assembled state, and fixing the measurement element set M at this time; S5. Replace the transducer under test, and obtain the K2 value of the new transducer under test under the condition of the measurement element set M, and so on. Batch testing obtains a K n sequence, and this sequence fluctuates within a certain range, so as to control the consistency of the core performance indicators of the finished transducer.

2. The general detection method for the piezoelectric properties of the piezoelectric ceramics of the underwater acoustic transducer according to claim 1, characterized in that The measurement element set M includes the installation position of the measured transducer, the installation position of the standard transducer, and the output parameters of the vibration tooling.

3. The general detection method for the piezoelectric properties of the piezoelectric ceramics of the underwater acoustic transducer according to claim 2, wherein, The transducer under test and the standard transducer are fixed at symmetrical positions at the same time, and the symmetrical vibration tooling is used to output vibration energy to both of them at the same time, including applying equal energy input to the transducer under test and the standard transducer at the same time, which is convenient for comparison in the subsequent test process.

4. The general detection method for the piezoelectric properties of the piezoelectric ceramics of the underwater acoustic transducer according to claim 3, characterized in that, Calculating the ratio of the two signal amplitudes includes: The amplitude average value of the same time window of the two signals is intercepted for calculation. The time window should be selected in the steady-state process of the two signals, and the non-steady-state signal should not be included in the time window.

5. A general detection device for the piezoelectric properties of a piezoelectric ceramic of an underwater acoustic transducer, based on the general detection method for the piezoelectric properties of the piezoelectric ceramic of the underwater acoustic transducer according to claim 4, characterized in that, include: A mounting bracket (1), arranged symmetrically, for mounting the transducer under test and the standard transducer; A vibration tool (2) is arranged on one side of the mounting bracket (1) and is used to output vibration energy to the transducer under test and the standard transducer at the same time; A vibration motor (4) is connected to the vibration tooling, and the vibration motor (4) is connected to a vibration control box (3). The signal acquisition system (6) is connected to the transducer under test and the standard transducer via a connecting cable (5), and the amplitudes of the two signals are intercepted by the host computer software, and a ratio comparison is performed.

6. The general detection device for the piezoelectric properties of the piezoelectric ceramics of the underwater acoustic transducer according to claim 5, characterized in that, The mounting bracket (1) is provided with an adjustment mechanism (7) for adjusting the mounting positions of the transducer under test and the standard transducer.

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