Piezoelectric composite material and regulation and control method thereof
The piezoelectric composite material with a flexible design and adjustable parameters addresses the limitations of traditional materials, enhancing their applicability in aerospace and biomedicine by combining a substrate, piezoelectric phase, and filling phase with a shunt circuit for parameter control.
Patent Information
- Application Number
- CN202411044048.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-31
- Publication Date
- 2024-12-20
Smart Images
Figure CN119173125A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of piezoelectric materials, in particular to a piezoelectric composite material and a control method thereof. Background Art
[0002] Traditional piezoelectric materials, such as inorganic piezoelectric ceramics, have excellent piezoelectric properties but are hard, brittle, and have poor flexibility, which limits their application in specific fields. The preparation method of piezoelectric composite materials mainly relies on uniformly dispersing inorganic piezoelectric material powder in thermoplastic polymers and then mixing and molding. During the preparation process of this method, the mechanical parameters of the material are difficult to control, making it difficult to meet the needs of specific applications. Due to the non-adjustability of the mechanical parameters of piezoelectric composites, their application in aerospace, biomedicine and other fields is limited and their potential cannot be fully realized. This method targets the limitations of poor flexibility and non-adjustable parameters of traditional piezoelectric materials.
[0003] At present, there is no piezoelectric composite material that has both excellent piezoelectric properties and good flexibility and can flexibly control mechanical parameters. Summary of the Invention
[0004] In view of the above problems in the prior art, the present invention is proposed.
[0005] Therefore, the first object of the present invention is to provide a piezoelectric composite material having good piezoelectric properties and good flexibility.
[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a piezoelectric composite material, comprising: a substrate, which is provided with small holes arranged in an array; a piezoelectric phase, which is arranged in the small holes and corresponds one-to-one to the small holes; and a filling phase, which is arranged between the piezoelectric phase and the inner wall of the small hole, and is used to fill the gap between the piezoelectric phase and the inner wall of the small hole.
[0007] As a preferred solution of the piezoelectric composite material of the present invention, the material of the piezoelectric phase is a relaxor ferroelectric single crystal.
[0008] As a preferred solution of the piezoelectric composite material of the present invention, a first electrode and a second electrode connected to the upper and lower surfaces of the piezoelectric phase are respectively provided.
[0009] As a preferred solution of the piezoelectric composite material of the present invention, the volume fraction ratio of the filling phase to the piezoelectric phase is 1:3.
[0010] Another object of the present invention is to provide a method for controlling a piezoelectric composite material, which can flexibly adjust the mechanical parameters of the piezoelectric composite material.
[0011] To solve the above technical problems, the present invention provides the following technical solutions: a method for regulating a piezoelectric composite material, which is applicable to the above-mentioned piezoelectric composite material, and the regulation method includes preliminarily adjusting the parameters of the piezoelectric composite material by adjusting the volume fraction of the piezoelectric phase; connecting a shunt circuit on both sides of the piezoelectric phase; and further adjusting the parameters of the piezoelectric composite material by adjusting the capacitance value, resistance value or inductance value in the shunt circuit.
[0012] As a preferred solution of the control method of the piezoelectric composite material of the present invention, the parameters include Young's modulus, shear modulus, acoustic velocity, acoustic impedance, bulk modulus and damping factor.
[0013] As a preferred embodiment of the method for regulating the piezoelectric composite material of the present invention, the method for regulating the volume fraction of the piezoelectric phase includes performing an equivalent analysis on a piezoelectric unit to obtain a relationship between the volume fraction of the piezoelectric phase and the equivalent parameters of the piezoelectric composite material; wherein, a piezoelectric unit includes a piezoelectric phase, a filling phase and a portion of a matrix.
[0014] As a preferred solution of the control method of the piezoelectric composite material described in the present invention, the equivalent analysis includes: selecting 1 / 4 of the piezoelectric unit as an equivalent unit; dividing the filling phase in the equivalent unit into a first filling unit and a second filling unit; connecting the first filling unit and its corresponding piezoelectric phase in equivalent series to obtain a first equivalent model; connecting the first equivalent model and the second filling unit in equivalent parallel to obtain a second equivalent model; and repeating the above steps with the first equivalent model as a new piezoelectric phase for secondary equivalence.
[0015] As a preferred solution of the control method of the piezoelectric composite material described in the present invention, the shunt circuit includes an impedance unit, the two ends of the impedance unit are respectively connected to the two ends of the piezoelectric phase; the impedance unit includes a capacitor, an inductor and a resistor connected in series.
[0016] As a preferred solution of the method for controlling the piezoelectric composite material of the present invention, the capacitor is a negative capacitor.
[0017] The beneficial effects of the present invention are as follows: the piezoelectric composite material provided by the present invention has both good flexibility and piezoelectric properties, and the control method provided can flexibly control the mechanical parameters of the piezoelectric material, so that the material properties match the actual application scenario. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0019] Figure 1 Schematic diagram of the structure of the piezoelectric composite material described in Example 1.
[0020] Figure 2 This is a schematic diagram of the substrate structure described in Example 1.
[0021] Figure 3 This is a schematic plan view of a piezoelectric unit described in Example 1.
[0022] Figure 4 Schematic diagram of the equivalent process described in Example 2.
[0023] Figure 5 This is a graph showing the effect of the change in the volume fraction of the piezoelectric phase on the equivalent elastic modulus of the piezoelectric material described in Example 2.
[0024] Figure 6 This is a graph showing the effect of the change in the volume fraction of the piezoelectric phase on the equivalent shear modulus of the piezoelectric material described in Example 2.
[0025] Figure 7 This is a graph showing the effect of the change in the volume fraction of the piezoelectric phase on the longitudinal wave velocity of the piezoelectric material as described in Example 2.
[0026] Figure 8 This is a graph showing the effect of the change in the volume fraction of the piezoelectric phase described in Example 2 on the longitudinal wave characteristic impedance of the piezoelectric material.
[0027] Figure 9 This is a graph showing the effect of the change in the volume fraction of the piezoelectric phase on the bulk modulus of the piezoelectric material as described in Example 2.
[0028] Figure 10 Schematic diagram of the piezoelectric shunt damping system described in Example 2.
[0029] Figure 11 This is a schematic diagram of the shunt circuit described in Example 2.
[0030] Figure 12 This is a graph showing the effect of the external capacitor on the Young's modulus of the piezoelectric material described in Example 2.
[0031] Figure 13 for Figure 12 A partial enlarged view of .
[0032] Figure 14This is a curve diagram showing the effect of the external capacitor on the damping factor of the piezoelectric material described in Example 2.
[0033] Figure 15 for Figure 14 A partial enlarged view of .
[0034] Figure 16 This is a curve diagram showing the effect of the external resistor on the Young's modulus of the piezoelectric material described in Example 2.
[0035] Figure 17 This is a curve diagram showing the effect of the external resistor on the damping factor of the piezoelectric material described in Example 2.
[0036] Figure 18 This is a curve diagram showing the effect of the external inductance on the Young's modulus of the piezoelectric material described in Example 2.
[0037] Figure 19 This is a curve diagram showing the effect of the external inductance on the damping factor of the piezoelectric material described in Example 2. DETAILED DESCRIPTION
[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0039] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0040] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it individually or selectively refer to an embodiment that is mutually exclusive of other embodiments.
[0041] Example 1
[0042] This embodiment provides a piezoelectric composite material. The piezoelectric composite material includes a matrix 100, a piezoelectric phase 200 and a filling phase 300. Figure 1 .
[0043] Specifically, the base 100 has a certain thickness, defined as hmm, and is made of epoxy resin. The base 100 is provided with a plurality of small holes 101 arranged in a uniform array. The small holes 101 are square and pass through the base 100. The side length of the small holes 101 is defined as bmm. This structural design allows the base 100 to maintain continuous connection in all three dimensions, thereby effectively serving as a supporting skeleton for the entire component. Figure 2 .
[0044] The piezoelectric phase 200, located at the center of each aperture 101, has a rectangular cross-section with a side length of a mm (b>a) and a thickness of h mm. The piezoelectric phase 200 is made of PMN-28PT (relaxor ferroelectric single crystal). Compared to the traditionally used PZT-5H, PMN-28PT exhibits superior piezoelectric performance and lower acoustic impedance.
[0045] The filling phase 300 has a cross section of a square ring with an outer side length of bmm and a thickness of hmm. The filling phase 300 wraps the piezoelectric phase 200, that is, the filling phase 300 completely fills the gap between the piezoelectric phase 200 and the substrate 100. The material of the filling phase 300 is silicone rubber, such as Figure 3 .
[0046] It is worth noting that a piezoelectric phase 200, a filling phase 300 and the surrounding matrix 100 constitute a piezoelectric unit. Figure 3 shown.
[0047] In addition, a first electrode 400 and a second electrode 500 are respectively provided on the upper and lower surfaces of the substrate 100 for connecting to an external circuit. The first electrode 400 and the second electrode 500 can be made of silver.
[0048] By changing the values of a and b, the volume fraction of the piezoelectric phase 200 can be changed. Preferably, by changing the values of a and b, the volume fraction of the filling phase 300 is always maintained at 25%.
[0049] Example 2
[0050] This embodiment is based on the previous embodiment. This embodiment provides a method for controlling a piezoelectric composite material, the method comprising:
[0051] S1: preliminarily adjusting the parameters of the piezoelectric composite material by adjusting the volume fraction of the piezoelectric phase 200 .
[0052] First of all, it should be noted that the 1-1-3 piezoelectric composite material (PCM) of the present invention is a three-phase composite material formed by a one-dimensionally connected piezoelectric phase 200 arranged in parallel in a three-dimensionally connected rigid polymer (matrix 100) and filled with a flexible polymer (filling phase 300). Figure 1As shown, the piezoelectric phase 200 retains the advantages of the piezoelectric actuator. The two polymers make this type of piezoelectric composite material have good flexibility and good compatibility with the base material. The piezoelectric phase 20 and the matrix 100 that make up the composite material can be expressed by the first kind of piezoelectric equations. The specific tensor forms are:
[0053]
[0054] Wherein, the superscripts p and m represent the piezoelectric phase 200 and the matrix 100, respectively, and ε i is the strain tensor, σ i is the stress tensor, E n is the electric field vector, D n is the electric displacement, s ij is the constant electric field flexibility coefficient, d ni d mj is the constant stress piezoelectric strain coefficient, ε mn is the constant stress dielectric constant. ij and ε mn The superscripts E and T are omitted respectively. When it is ensured that there will be no confusion, the same omission will be done in the following text to ensure the simplicity of the formula.
[0055] Secondly, for Figure 1 For a 1-1-3 piezoelectric composite material with a rectangular cross section, we can take 1 / 4 of its representative typical units (cells) perpendicular to the fiber arrangement direction (z direction) for analysis and equivalence. For the specific equivalence process, refer to Figure 4 :
[0056] (I): The piezoelectric phase 200 and the first filling unit 301 are connected in series to obtain a first equivalent model 701;
[0057] (II): The first equivalent model 701 and the remaining filling phase 300 , i.e., the second filling unit 302 , are connected in parallel to obtain a second equivalent model 702 .
[0058] (III): The composite material obtained in the equivalent process (1), i.e., the first equivalent model 701, is used as the piezoelectric phase of the equivalent process (2) to repeat the above two steps and perform the secondary equivalent again.
[0059] In the process (1), according to the continuity condition and the mixing law, the equivalent mechanical properties in directions 1, 2, and 3 respectively satisfy:
[0060]
[0061] Where, denote the volume fractions of the piezoelectric phase 200 and the matrix 100 in the analysis model of process (I), respectively. The equivalent electrical parameters obtained in process (I) are denoted by the subscript I. Based on the continuity condition and the law of mixing, the equivalent electrical properties in directions 1, 2, and 3 satisfy the following equations:
[0062]
[0063] Finally, the equivalent piezoelectric constitutive equation of process (I) is solved:
[0064]
[0065] Where, They represent the strain tensor, stress tensor, electric displacement vector, constant electric field compliance coefficient, and constant stress dielectric constant after the equivalent process (I), respectively. The piezoelectric strain coefficient of constant stress after equivalent process (I).
[0066] Referring to the equivalent method of process (I), the equivalent mechanical properties in directions 1, 2, and 3 in process II are derived. Subsequently, process (III) uses the equivalent parameters obtained in processes (I) and (II) as new piezoelectric phase parameters and substitutes them into the above two equivalent processes for iteration to obtain the final equivalent parameters.
[0067] During this process, users can preliminarily select the appropriate volume fraction of the piezoelectric phase 200 according to their specific needs. The piezoelectric phase specially selected in this invention is PMN-28PT (relaxor ferroelectric single crystal). Compared with the traditional commonly used PZT-5H, PMN-28PT exhibits more excellent piezoelectric performance and lower acoustic impedance, which makes it have significant advantages in various application scenarios. Figures 5 to 9 The equivalent parameters when using PMN-28PT as the piezoelectric phase are shown in detail and compared with those of PZT-5H. As can be seen from the figure, the equivalent parameters of 1-1-3 type PCM (PMN) and 1-1-3 type PCM (PZT) have the same trend of change, and both gradually increase as the volume fraction of the piezoelectric phase increases from 0 to 1.
[0068] Equivalent elastic modulus E3( Figure 5 ), equivalent shear modulus G 31 ( Figure 6 ) and longitudinal wave characteristic impedance Z L ( Figure 8 ) gradually transition from the substrate 100 (epoxy resin) to the piezoelectric phase 200, and the equivalent parameters gradually increase. L ( Figure 7 ) first decreases and then increases.
[0069] It is worth emphasizing that if Figure 7As shown in the figure, the minimum longitudinal wave sound velocity of the 1-1-3 type PCM (PMN) is lower than that of the 1-1-3 type PCM (PZT), and the corresponding piezoelectric phase 200 volume fractions are 15.48% (PMN) and 24.45% (PZT), respectively. Therefore, the 1-1-3 type PCM (PMN) has better piezoelectric performance and sound absorption potential than the 1-1-3 type PCM (PZT).
[0070] In summary, the mechanical parameters of the piezoelectric composite material can be preliminarily adjusted by adjusting the volume fraction of the piezoelectric phase 200 .
[0071] S2: Connect the shunt circuit 600 on both sides of the piezoelectric phase 200.
[0072] Specifically, when the piezoelectric composite material is subjected to stress in a specific direction (eg, 3 directions), a shunt circuit 600 is connected to both sides of the piezoelectric phase 200, and its impedance is represented by Z(S).
[0073] According to the definition of piezoelectric shunt damping system, its structural diagram is as follows: Figure 10 As shown, V represents the voltage across the piezoelectric phase 200 , and I represents the current in the external shunt circuit 600 .
[0074] To further explain the operating principle of this system, Figure 11 A negative capacitance piezoelectric shunt damping circuit model is presented, in which I p represents the current source of the equivalent circuit of the piezoelectric phase 200, while the capacitive reactance is related to the characteristics of the piezoelectric phase 200 itself. V represents the voltage across the shunt circuit, and the capacitor 601a, inductor 601b, and resistor 601c in the impedance unit 601 are connected in series. Capacitor 601a is a negative capacitor.
[0075] S3: further adjusting the parameters of the piezoelectric composite material by adjusting the capacitance value, resistance value or inductance value in the shunt circuit 600 .
[0076] Specifically, the system achieves effective control of key mechanical properties of the piezoelectric composite material by precisely adjusting the electrical impedance parameters in the external shunt circuit 600. The equivalent theory of the parameters of the external shunt circuit 600 is as follows:
[0077]
[0078] Among them, h p,j is the thickness of the piezoelectric composite material, A p,j is the surface area of the piezoelectric composite material, s ij is the constant electric field flexibility coefficient, d ni d mj is the constant stress piezoelectric strain coefficient, C pis the inherent capacitance of the piezoelectric material, Z is the external circuit impedance, R s is the resistance value of resistor 601c, L s is the inductance of inductor 601b, C s is the value of capacitor 601a.
[0079] Furthermore, the system achieves effective control of the Young's modulus and damping factor of the piezoelectric composite material by adjusting the values of the resistor 601c, the inductor 601b and the capacitor 601a in the external circuit 600.
[0080] Preferably, a piezoelectric composite material with a volume fraction of 16% of the piezoelectric phase 200 is selected as the test object, and the values of the resistance 601c, inductance 601b and capacitance 601a in the shunt circuit 600 are adjusted at the same time. It can be found that the changes in the resistance 601c, inductance 601b and capacitance 601a will have different degrees of influence on the material parameters.
[0081] in Figures 12 to 15 The effect of capacitance 601a on material parameters is shown. Figure 16 and Figure 17 The effect of resistance 601c on material parameters is shown. Figure 18 and Figure 19 The effect of the inductor 601b on the material parameters is shown.
[0082] In summary, by adding the external circuit 600 and adjusting the values of the resistor 601c, the inductor 601b and the capacitor 601a in the external circuit 600, the mechanical parameters of the piezoelectric material can be controlled.
[0083] Therefore, the beneficial effects of the present invention are:
[0084] 1. Optimized Material Performance: The PMN-28PT (relaxor ferroelectric single crystal) used in the Piezoelectric Phase 200 exhibits superior piezoelectric performance and lower acoustic impedance compared to the traditionally used PZT-5H. By combining two polymers, epoxy resin and silicone rubber, lateral coupling is effectively reduced, significantly improving its piezoelectric performance.
[0085] 2. Adjustable mechanical parameters: The piezoelectric composite material of the present invention can first preliminarily adjust the material properties and mechanical parameters by adjusting the volume fraction of the piezoelectric phase 200. Then, by adjusting the electrical impedance in the external shunt circuit 600, it is possible to achieve efficient regulation of the Young's modulus, Poisson's ratio, shear modulus and bulk modulus of the piezoelectric composite material, thereby ensuring that the material performance matches the actual application scenario.
[0086] 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 the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.
Claims
1. A piezoelectric composite material, Features: include, A substrate (100) having small holes (101) arranged in an array; A piezoelectric phase (200) is disposed in the small hole (101) and corresponds one-to-one with the small hole (101); The filling phase (300) is arranged between the piezoelectric phase (200) and the inner wall of the small hole (101) and is used to fill the gap between the piezoelectric phase (200) and the inner wall of the small hole (101).
2. The piezoelectric composite material according to claim 1, Features: The material of the piezoelectric phase (200) is a relaxor ferroelectric single crystal.
3. The piezoelectric composite material according to claim 2, Features: A first electrode (400) and a second electrode (500) connected thereto are respectively arranged on the upper and lower surfaces of the piezoelectric phase (200).
4. The piezoelectric composite material according to claim 3, Features: The volume fraction ratio of the filling phase (300) to the piezoelectric phase (200) is 1:
3.
5. A method for regulating a piezoelectric composite material, Features: Applicable to the piezoelectric composite material according to any one of claims 1 to 4, the control method comprises: Preliminarily adjusting the parameters of the piezoelectric composite material by adjusting the volume fraction of the piezoelectric phase (200); Connecting a shunt circuit (600) on both sides of the piezoelectric phase (200); The parameters of the piezoelectric composite material are further adjusted by adjusting the capacitance value, resistance value or inductance value in the shunt circuit (600).
6. The method for controlling the piezoelectric composite material according to claim 5, Features: The parameters include Young's modulus, shear modulus, acoustic velocity, acoustic impedance, bulk modulus, and damping factor.
7. The method for controlling the piezoelectric composite material according to claim 6, Features: The method for adjusting the volume fraction of the piezoelectric phase (200) comprises performing an equivalent analysis on a piezoelectric unit to obtain a relationship between the volume fraction of the piezoelectric phase (200) and an equivalent parameter of the piezoelectric composite material; Wherein, one of the piezoelectric units comprises one of the piezoelectric phases (200), a filling phase (300) and a part of the matrix (100).
8. The method for controlling the piezoelectric composite material according to claim 7, Features: The equivalence analysis includes, Selecting a quarter of the piezoelectric unit as an equivalent unit (700); Dividing the filling phase (300) in the equivalent unit (700) into a first filling unit (301) and a second filling unit (302); Connecting the first filling unit (301) and the corresponding piezoelectric phase (200) in equivalent series to obtain a first equivalent model (701); The first equivalent model (701) and the second filling unit (302) are connected in parallel to obtain a second equivalent model (702); The above steps are repeated using the first equivalent model (701) as a new piezoelectric phase (200) to perform secondary equivalence.
9. The method for controlling the piezoelectric composite material according to claim 8, Features: The shunt circuit (600) comprises an impedance unit (601), and two ends of the impedance unit (601) are respectively connected to two ends of the piezoelectric phase (200); The impedance unit (601) comprises a capacitor (601a), an inductor (601b) and a resistor (601c) which are connected in series.
10. The method for controlling the piezoelectric composite material according to claim 9, Features: The capacitor (601a) is a negative capacitor.