CN110427650B - Numerical simulation analysis method for basic characteristics of moving-iron loudspeaker - Google Patents
Numerical simulation analysis method for basic characteristics of moving-iron loudspeaker Download PDFInfo
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Abstract
The invention discloses a numerical simulation analysis method for basic characteristics of a moving-iron type loudspeaker, which is divided into two parts. The first part is to simulate and analyze the magnetic field change caused by the position change of the balance armature, and the magnetic field change can cause the change of electromotive force and electromagnetic force. The first part calculates to obtain the variation relation between the electromotive force on the coil and the electromagnetic force on the armature along with the displacement of the armature; the second part is that based on the first part, the basic characteristics of the moving iron type loudspeaker are simulated and analyzed, and the basic characteristics comprise an impedance curve, a sound pressure level frequency response curve, sound pressure and sound pressure level distribution and the like of the loudspeaker. Both parts of the process of the invention comprise 6 main steps: 1) Establishing a geometric model; 2) Setting a physical field and boundary conditions; 3) Defining material parameters; 4) Setting the type and size of the grid and dividing the grid; 5) Solving and calculating; 6) And (5) carrying out aftertreatment on the result.
Description
Technical Field
The invention belongs to the field of moving-iron loudspeakers, and relates to a numerical simulation analysis method relating to electromagnetism, structural mechanics and acoustics. By adopting the numerical simulation analysis method disclosed by the invention, the results of sound pressure level frequency response curve, impedance curve, sound pressure and sound pressure level distribution and the like of the moving-iron type loudspeaker can be obtained. The simulation analysis results can be used for guiding the structural design and improvement of the moving-iron type loudspeaker so as to improve the performance of the moving-iron type loudspeaker.
Background
The moving-iron type speaker, also called a Balanced Armature type (Balanced Armature) speaker, has advantages of a small size, a high electro-acoustic conversion efficiency, and a high sensitivity. Compared with the traditional moving-coil loudspeaker, the moving-iron loudspeaker also has high resolution, and can truly restore the details of the original signal; in addition, due to the advantage of small volume, a plurality of sound production units can be placed in the earphone and are respectively responsible for sound restoration of different sound ranges, so that low, medium and high frequency balance is achieved, and higher sensitivity, excellent transient response and sound density are brought. Moving-iron loudspeakers have proven to be one of the ideal solutions for achieving high-quality audio reproduction in small-volume products.
The method for designing and improving the moving-iron type loudspeaker in an enterprise is still the traditional empirical method, and because the design theory is still imperfect, the development process of trial-making a sample, testing, improving the sample and retesting is adopted, so the development cost is higher, and the development period is longer.
With the development of computer technology, the auxiliary design of the numerical simulation analysis method becomes more and more extensive, and the performance of a product can be estimated at the early stage of sample trial making by applying the numerical simulation analysis method to the design of the moving-iron type loudspeaker, so that the defects of a design theory are overcome, the development progress of the moving-iron type loudspeaker can be accelerated, and the development cost is reduced.
Disclosure of Invention
The invention aims to design a numerical simulation method of basic characteristics of a moving-iron type loudspeaker, and solves the problems that the design theory of the existing moving-iron type loudspeaker is imperfect, the method for designing and improving the moving-iron type loudspeaker is still a traditional empirical method, the development cost is high and the like. According to the invention, by establishing a finite element simulation analysis model of the moving-iron type loudspeaker, a sound pressure level frequency response curve, an impedance curve, sound pressure and a sound pressure level distribution diagram and the like of the moving-iron type loudspeaker can be calculated, the basic characteristics of the moving-iron type loudspeaker can be estimated according to a simulation analysis result, and the result is used for guiding the structural design and improvement of the moving-iron type loudspeaker.
The invention discloses a numerical simulation analysis method for basic characteristics of a moving-iron loudspeaker, which is divided into two parts: the first part is used for simulating and analyzing the influence of the displacement of the balanced armature on the electromotive force and the electromagnetic force; and the second part is to simulate and analyze the basic characteristics of the moving-iron type loudspeaker, such as a sound pressure level frequency response curve, an impedance curve and the like on the basis of the first part. These two parts will be described separately below.
In the numerical simulation analysis method of the basic characteristics of the moving-iron type loudspeaker, the simulation analysis method of the first part uses two physical fields of solid mechanics and magnetic field, and the simulation analysis method of the first part mainly comprises the following steps:
(1) Establishing a finite element model
1) Establishing a geometric model: and importing the geometric model of the moving-iron type loudspeaker into finite element analysis software, wherein the geometric model is drawn by adopting three-dimensional drawing software or is established by adopting the self geometric modeling function of the finite element analysis software. After the geometric model is established, redundant points, lines, surfaces and bodies need to be cleaned so as to improve the quality of the geometric model;
2) Setting a physical field and boundary conditions, and specifically comprising the following steps:
A. selecting a physical field corresponding domain of a magnetic field, wherein the physical field corresponding domain comprises a domain corresponding to each component of the moving-iron loudspeaker and an air domain;
B. under the magnetic field, setting the material constitutive relation of the magnetic steel as residual magnetic flux density and setting a residual magnetic flux density parameter value; the constitutive relation refers to a mathematical model reflecting the property of a substance.
C. Under the magnetic field, the material constitutive relation of the magnetic yoke is a B-H curve, and the B-H curve value of the magnetic yoke is introduced under the material parameters. The B-H curve here is obtained by testing;
D. under the 'magnetic field', the material constitutive relation of the voice coil, the balance armature and the air part is set as 'relative magnetic conductivity';
E. selecting a physical field corresponding domain of 'solid mechanics', namely a balanced armature domain;
F. under the 'solid mechanics', the material constitutive relation of the balance armature is 'linear elastic material';
G. under the 'solid mechanics', a 'fixed constraint' surface is arranged at the fixed position of the balance armature;
H. under "solid mechanics", the upper surface of the balanced armature in the magnetic gap is set to a parameterized "boundary force load", said parameter
The digitized boundary force load is denoted as FF;
I. under the 'solid mechanics', the symmetrical plane of the balance armature is set as a 'symmetrical' boundary;
J. selecting a 'moving grid' physical field corresponding domain which comprises a balanced armature domain and an air domain;
K. under the 'moving grid', setting an air domain as 'free deformation';
l, under the 'moving grid', setting the balanced armature as 'specified deformation', wherein the displacements of the specified grid in X, Y and Z directions are u, v and w respectively;
m, under the 'moving grid', setting the outer surface (except a fixed surface and a symmetrical surface) of the balanced armature as 'appointed grid displacement', wherein the displacements of the appointed grid in X, Y and the Z direction are u, v and w respectively;
n, under the 'moving grid', setting a symmetrical plane of an air domain and a balanced armature as 'appointed grid displacement', and appointing the displacement in the normal direction to be 0;
3) Defining material parameters: here, material parameters of the moving-iron type loudspeaker need to be set respectively, wherein the material parameters comprise material parameters of a balanced armature, a vibrating diaphragm and soft iron, and the material parameters comprise Young modulus, density, poisson ratio and damping;
4) Grid division: specifying the type and size of grid cells, and dividing grids, wherein local grid refinement is carried out appropriately by setting the size of the grid cells, so that the calculation result is more accurate;
(2) Solving and post-processing;
1) Solving: by adopting steady-state research, the variation of the magnetic flux in the coil and the Maxwell stress tensor of the armature surface along with the armature displacement when the balanced armature is in different displacements is calculated; the 'steady state' research is a finite element software built-in research method, and the solving and calculating process is completed by a software built-in algorithm.
2) And (4) carrying out aftertreatment on the result: after the solution is completed, the post-processing operation is adopted to obtain: 1) Calculating the change relation of the induced electromotive force in the coil along with the displacement of the armature according to the change of the magnetic flux in the coil, and recording the change relation as U (x); 2) Calculating the variation relation of the electromagnetic force on the armature along with the displacement of the armature according to the Maxwell stress tensor of the surface of the armature, and recording the variation relation as F (x);
in the numerical simulation analysis method of the basic characteristics of the moving-iron type loudspeaker, the simulation analysis method of the second part uses a multi-physical-field interface of pressure acoustics, frequency domain, magnetic field, solid mechanics physical field and sound-structure boundary, and the simulation analysis method of the second part mainly comprises the following steps:
(1) Establishing a finite element model
1) Establishing a geometric model, which comprises the following specific steps:
A. establishing a geometric loudspeaker model: the geometric model of the moving-iron type loudspeaker is led into finite element analysis software (the geometric model of the loudspeaker can be drawn by adopting three-dimensional drawing software), and the geometric model of the loudspeaker can be established by adopting the geometric modeling function of the finite element analysis software. After the geometric model is established, redundant points, lines, surfaces and bodies in the model need to be cleaned so as to improve the quality of the geometric model;
B. establishing 711 a coupler acoustic cavity equivalent model: the sound pressure level frequency response curve of a moving-iron speaker is typically tested in the 711 coupler; to make the simulation analysis method more versatile, an acoustic cavity equivalent model (including a connection tube) of the 711 coupler is established and connected to the speaker correctly. The 711 coupler refers to a human ear simulator;
2) Setting a physical field and boundary conditions, and specifically comprising the following steps:
A. selecting a physical field corresponding domain of a 'magnetic field', wherein the physical field corresponding domain comprises a domain corresponding to each component of the moving-iron type loudspeaker and an air domain;
B. under the magnetic field, setting the material constitutive relation of the magnetic steel as residual magnetic flux density, and setting the parameter values of the residual magnetic flux density and the like; the constitutive relation refers to a mathematical model reflecting the property of a substance;
C. under the magnetic field, setting the material constitutive relation of the magnetic yoke as a B-H curve, and introducing the B-H curve value of the magnetic yoke under the material parameters; the B-H curve here is obtained by testing;
D. under the 'magnetic field', the material constitutive relation of the voice coil, the balance armature and the air part is set as 'relative magnetic conductivity';
E. under the 'magnetic field', adding a 'coil' domain, inputting turns and wire diameter, and setting a 'disturbance wave disturbance voltage value' and 'geometric analysis' of the coil; the coil harmonic disturbance voltage value is U0-U (x), U0 is external loading voltage, and U (x) is induced electromotive force generated in the coil by armature movement;
F. under the 'magnetic field', an 'external current density', namely an induced current generated by cutting a magnetic induction line by the balance armature, is arranged on the balance armature;
G. under the magnetic field, setting force calculation for balancing the armature area, and calculating the stress tensor Wei Biaomian of the armature in the magnetic field;
H. selecting a physical field corresponding domain of 'solid mechanics', wherein the physical field corresponding domain comprises a balanced armature, a vibrating diaphragm and a linkage rod;
I. under the 'solid mechanics', the material constitutive relation of the balance armature, the vibrating diaphragm and the connecting rod is 'linear elastic material', and the damping type and the damping value of the materials are set;
J. under the solid mechanics, a fixed constraint surface is arranged at the fixed position of the balance armature and the vibrating diaphragm;
K. under the condition of solid mechanics, setting the boundary load of the surface of the balanced armature, wherein the load type is set as the stress tensor of Max Wei Biaomian on the unit area;
under the 'solid mechanics', setting 'boundary load' on the upper surface of a balance armature in a magnetic gap, wherein the load is F (x), namely considering the variation relation of Maxwell stress tensor (magnetic force) on the surface of the armature along with the displacement of the armature;
m, under the solid mechanics, setting the symmetrical surfaces of the balance armature, the connecting rod and the vibrating diaphragm as symmetrical boundaries;
selecting a physical field corresponding domain of 'pressure acoustics, frequency domain', wherein the physical field corresponding domain comprises an air domain in a loudspeaker and an air domain in an 711 sound cavity of a coupler;
o. under "pressure acoustics, frequency domain", set up "narrow area acoustics" in the slit of the pressure balance hole, front cavity and 711 coupler;
p. under "pressure acoustics, frequency domain", the microphone end face of 711 coupler is set as the "impedance" boundary of "series coupling RCL", where R is equivalent acoustic resistance, C is equivalent acoustic compliance, and L is equivalent acoustic inertia;
setting the outer end face of the pressure balance hole as an impedance boundary of the tail end of the waveguide with the flange under the conditions of pressure acoustics and frequency domain;
r, setting an acoustic-structure boundary under a multi-physical-field interface for coupling solid mechanics and a sound field;
3) Defining material parameters: the method comprises the steps of setting material parameter values of components such as a balance armature, a vibrating diaphragm, soft iron, magnetic steel and the like of the moving-iron type loudspeaker and air, wherein the material parameter values mainly comprise Young modulus, density, poisson ratio, damping, dynamic viscosity, conductivity, dielectric constant and the like.
4) Grid division: and (3) specifying the type of the grid unit to obtain a finite element grid model, and properly encrypting grids in the pressure balance hole, the air domains of the front cavity and the rear cavity, the balance armature, the magnetic gap and the narrow air domain of the 711 coupler to ensure that the calculation result is more accurate.
(2) Solution and post-processing
1) Solving: in the simulation analysis of the moving-iron type loudspeaker, the finite element model is solved by adopting the research of 'coil geometric analysis + small signal frequency domain disturbance'. Here, "coil geometry analysis" is mainly used to solve the characteristics of the coil of the moving-iron type speaker; the research of 'geometric analysis of coil + small signal frequency domain disturbance' is a software built-in research method, and the calculation process is completed by a software built-in algorithm;
2) And (4) carrying out result post-treatment: after the solution is completed, the post-processing operation is adopted to obtain the basic characteristics of the moving-iron type loudspeaker, and the basic characteristics mainly comprise: A. the sound pressure level frequency response curve of the moving-iron loudspeaker; B. the impedance curve of the moving-iron loudspeaker; C. sound pressure and sound pressure level distribution in the acoustic cavity.
The geometric model of the moving-iron loudspeaker simulation analysis is a reasonably simplified model. The model simplification method is multiple, and the model simplification can be finished by adopting professional three-dimensional drawing software (such as SolidWorks, proE and the like) or realized by adopting a relevant function of geometry in finite element software.
The finite element analysis software is COMSOL Multiphysics (COMSOL for short), is a multi-physical-field simulation analysis software, and mainly has the functions of establishing a geometric model, dividing grids, setting and solving physical fields, displaying results in an imaging mode and the like.
The invention has the advantages that: 1) The method comprehensively considers the mutual coupling relation among a magnetic circuit system, a vibration system and a sound field of the moving-iron type loudspeaker, and obtains the basic characteristics of a sound pressure level frequency response curve, an impedance curve and the like of the moving-iron type loudspeaker through three-field coupling simulation calculation; 2) The invention can quickly, cheaply and accurately estimate the basic characteristics of the moving-iron type loudspeaker, thereby shortening the research and development period of the moving-iron type loudspeaker and improving the product performance.
Drawings
FIG. 1 is a flow chart of the present invention.
FIG. 2 is a geometric model of a first portion of the simulation analysis.
FIG. 3 is a physical field set-up for a first portion of simulation analysis.
Fig. 4 shows the material parameters (a) and the soft-iron BH curve (b) of the first part of the simulation analysis.
FIG. 5 is a finite element mesh model of the first part of the simulation analysis.
FIG. 6 is a geometric model of a second portion of the simulation analysis.
FIG. 7 is a physical field set-up for a second portion of the simulation analysis.
Fig. 8 shows the acoustic impedance boundary of the face of the 711 coupler where the microphone is located.
FIG. 9 is an acoustic impedance boundary of a pressure balance port end face.
Fig. 10 shows material parameters of the second part of simulation analysis.
FIG. 11 is a finite element mesh model of the second portion of the simulation analysis.
Fig. 12 is a sound pressure level frequency response curve of the moving iron type speaker.
Fig. 13 is an impedance curve of the moving-iron type speaker.
Fig. 14 is a graph of the sound pressure distribution within the acoustic cavity of the moving iron speaker and 711 coupler.
Fig. 15 is a graph of the sound pressure level distribution within the acoustic cavity of the moving-iron speaker and 711 coupler.
Detailed Description
The invention is further explained below with reference to the drawings and the examples.
Taking a moving-iron type loudspeaker as an example, the basic characteristics of the loudspeaker in magnetic fields, structural mechanics and sound fields are analyzed by using the numerical simulation method disclosed by the invention.
Fig. 1 is a flow chart of the present invention, and the simulation analysis process of the embodiment is divided into two parts: the first part simulates the influence of the displacement of the balanced armature on the coil electromotive force and the electromagnetic force on the armature; and the second part is to simulate and analyze the basic characteristics of the moving-iron type loudspeaker, such as sound pressure level frequency response, impedance curve and the like on the basis of the first part. The following describes the specific implementation steps of these two parts, which are as follows:
1. in the numerical simulation analysis method of the basic characteristics of the moving-iron type loudspeaker, the first part of simulation analysis methods comprises the following specific steps:
(1) Preparation of
Drawing a three-dimensional structure diagram of the moving-iron loudspeaker. The structure chart of the loudspeaker can be drawn by professional three-dimensional drawing software such as SolidWorks and the like, and can also be drawn by a 'geometric' function in COMSOL software,
(2) Establishing a finite element model
1) Add spatial dimensions, physical field interfaces, and study types. And (3) opening COMSOL software, setting the spatial dimension to be three-dimensional, sequentially selecting and adding three physical fields of solid mechanics, magnetic field and dynamic grid, and selecting the research type to be stable state.
2) A geometric model is established as shown in fig. 2. The concrete modeling steps are as follows:
A. establishing a geometric model of the loudspeaker: importing a digital model of the moving-iron loudspeaker into finite element analysis software (the digital model of the loudspeaker is obtained by drawing the three-dimensional drawing software), or establishing a geometric model of the moving-iron loudspeaker by adopting a geometric modeling function of the finite element analysis software;
B. geometric cleaning: in the process of constructing the finite element model, because redundant points, lines, surfaces and bodies in the geometric model can cause great influence on the grid quality, after the geometric model is introduced, the redundant points, lines, surfaces and bodies in the model are eliminated by adopting a geometric cleaning function.
3) Setting physical fields and boundary conditions. The detailed setting steps are as follows:
A. the "magnetic field" physical field is selected to correspond to domain (1). They include the corresponding fields and air fields for the various components of the moving iron loudspeaker, see fig. 3;
B. under the condition of 'magnetic field', the material constitutive relation of the magnetic steel is 'residual magnetic flux density', the residual magnetic flux density is input to be 1.2 < T >, and the relative magnetic permeability and the electric conductivity are both 'from material';
C. under the magnetic field, the constitutive relation of the materials of the magnetic yoke is a B-H curve, and a magnetic field model (namely the B-H curve) is arranged from the materials;
D. under the 'magnetic field', setting the material constitutive relation of the voice coil, the balance armature and the air part as 'relative permeability', and setting the relative permeability, the electrical conductivity and the relative dielectric constant 'from materials';
E. selecting a 'solid mechanics' physical field corresponding domain (2), namely a balanced armature domain, as shown in figure 3;
F. under the 'solid mechanics', the material constitutive relation of the balance armature is 'linear elastic material';
G. under the solid mechanics, a fixed constraint surface is arranged at the fixed position of the balance armature;
H. under the 'solid mechanics', the upper surface of a balance armature in a magnetic gap is set as a parameterized 'boundary force load', the parameterized boundary force load is recorded as FF, and the FF is defined as a global parameter;
I. under the 'solid mechanics', the symmetrical plane of the balance armature is set as a 'symmetrical' boundary;
J. selecting 'moving grid' physical field corresponding domains (3) which comprise balanced armature domains and air domains;
K. under the 'moving grid', setting an air domain as 'free deformation';
l, under the 'moving grid', setting the balanced armature as 'specified deformation', wherein the displacements of the specified grid in X, Y and the Z direction are u, v and w respectively;
m, under the 'moving grid', setting the outer surface (except a fixed surface and a symmetrical surface) of the balanced armature as 'appointed grid displacement', wherein the displacements of the appointed grid in X, Y and the Z direction are u, v and w respectively;
and N, under the 'moving grid', setting a symmetrical plane of the air domain and the balance armature as 'appointed grid displacement', and appointing the displacement in the normal direction to be 0.
4) Defining material parameters: the parameter values required to be set by each component during simulation analysis are closely related to the physical field setting. Here, material parameters of the moving-iron type speaker balanced armature, the diaphragm, the soft iron and other structures need to be set respectively, and mainly include young modulus, density, poisson ratio, damping and the like, which are detailed in fig. 4 (a); the BH value of the soft magnetic material (yoke) needs to be introduced as well, as shown in fig. 4 (b) in detail.
5) Grid division: the finite element mesh model generated in this example is shown in FIG. 5. When the grid is divided, the type of the designated grid unit is free tetrahedral grid, and the local grid is properly refined through size control, so that the calculation result is more accurate.
(3) Solution and data processing
1) Solving for
By adopting steady-state research, the variation of the magnetic flux in the coil and the Maxwell stress tensor of the armature surface along with the armature displacement when the balanced armature is in different displacements is calculated;
2) Data processing
A. According to magnetic flux in the coil
Calculating to obtain the change relation of the induced electromotive force in the coil along with the displacement of the armature, and recording as U (x);
B. and calculating the change relation of the electromagnetic force on the armature along with the displacement of the armature according to the Maxwell stress tensor of the surface of the armature, and recording the change relation as F (x). 2. In the numerical simulation analysis method of the basic characteristics of the moving-iron type loudspeaker, the second part of simulation analysis method comprises the following specific steps:
(1) Preparation of
The sound pressure level frequency response curve of the moving-iron type loudspeaker is usually tested in the 711 coupler, and in order to make the simulation analysis method more universal, the digital-analog of the equivalent sound cavity and the connecting pipe of the 711 coupler is also required to be established besides the digital-analog of the moving-iron type loudspeaker.
(2) Establishing a finite element model
1) Establishing a geometric model, as shown in fig. 6, the specific steps are as follows:
A. establishing a geometric model of the loudspeaker: importing a digital model of the moving-iron type loudspeaker into COMSOL software (the digital model of the loudspeaker is obtained by drawing three-dimensional drawing software), or establishing a geometric model of the moving-iron type loudspeaker by adopting a geometric modeling function of finite element analysis software;
B. establishing 711 a coupler acoustic cavity equivalent model: the digital-to-analog of the 711 coupler's acoustic cavity equivalent model (with connecting tubes) is imported into COMSOL software and connected to the speaker correctly. Here, in order to reduce the amount of calculation, both the moving-iron type speaker and the acoustic cavity adopt a 1/2 symmetrical structure.
C. Geometric cleaning: in the process of constructing the finite element model, because redundant points, lines, surfaces and bodies in the geometric model can cause great influence on the grid quality, after the geometric model is introduced, the redundant points, lines, surfaces and bodies in the model are eliminated by adopting a geometric cleaning function.
2) Setting a physical field and boundary conditions, and specifically comprising the following steps:
A. selecting physical field corresponding domains of a 'magnetic field', wherein the physical field corresponding domains comprise domains corresponding to all components of the moving-iron loudspeaker and air domains;
B. under the condition of 'magnetic field', the material constitutive relation of the magnetic steel is 'residual magnetic flux density', the residual magnetic flux density is input to be 1.2 < T >, and the relative magnetic permeability and the electric conductivity are both 'from material';
C. under the magnetic field, the material constitutive relation of the magnetic yoke is set as a B-H curve, and a magnetic field model (namely the B-H curve) is set from the material;
D. under the magnetic field, setting the material constitutive relation of the balance armature and the air part as relative permeability, and setting the relative permeability, the electrical conductivity and the relative dielectric constant as from the material;
E. under the condition of a magnetic field, a coil field is added, a coil wire model is set to be a uniform multi-turn model, and the number of turns N =450, the cross-sectional area a =1.96e-9[m are input 2 ]And coil voltage and other parameters, and setting geometric analysis to define the current direction in the coil; here, considering that the change of magnetic flux in the coil can affect the potential in the coil, the disturbance voltage of the coil is set to be U0-U (x), U0 is the external disturbance voltage, and U (x) is the induced electromotive force generated in the coil by the movement of the armature;
F. under the 'magnetic field', an 'external current density', namely an induced current generated by cutting a magnetic induction line by the balance armature, is arranged on the balance armature;
G. under the magnetic field, setting a force calculation for balancing the armature field, wherein the force calculation is used for calculating the stress tensor Wei Biaomian of the armature in the magnetic field;
H. selecting corresponding domains of a solid mechanics physical field, wherein the corresponding domains comprise a balanced armature, a vibrating diaphragm and a linkage rod;
I. under the 'solid mechanics', the material constitutive relation of the balance armature, the vibrating diaphragm and the connecting rod is 'linear elastic material', the damping types of the materials are 'isotropic loss', and the damping value is 'from material';
J. under the 'solid mechanics', the fixed positions of the balance armature and the vibrating diaphragm are set as 'fixed constraint' boundaries;
K. under the condition of solid mechanics, the surface of the balanced armature is set as boundary load, and the load type is set as Maxwell Wei Biaomian stress tensor on unit area;
under the 'solid mechanics', setting 'boundary load' on the upper surface of a balance armature in a magnetic gap, wherein the load is F (x), namely considering the variation relation of Maxwell stress tensor (magnetic force) on the surface of the armature along with the displacement of the armature;
m, under the 'solid mechanics', setting the symmetrical surfaces of the balance armature, the connecting rod and the vibrating diaphragm as 'symmetrical' boundaries;
n. select the "pressure-acoustic, frequency-domain" physical field corresponding domain (4), which includes the air-domain inside the speaker and the air-domain inside the 711 coupler acoustic cavity, see fig. 7;
o. under "pressure-acoustic, frequency domain", a "narrow-zone acoustic" corresponding domain (5) is set, i.e. a narrow-zone air domain inside the 711 coupler acoustic cavity, see fig. 7. Setting corresponding catheter type and geometric dimension parameters;
p. in the "pressure acoustic, frequency domain", the face (6) where the 711 coupler microphone is located is set as the "impedance" boundary of the "series coupling RCL", see fig. 8, and the equivalent acoustic resistance R =119e6[ n · s/m ] is set 5 ]Equivalent compliance C =0.62e-13[ m ] 5 /N]And equivalent acoustic inertia L =710[ 2 ] kg/m 4 ]。
Under the conditions of pressure acoustics and frequency domain, the outer end face (7) of the pressure balance hole is set as an impedance boundary of a waveguide tail end with a flange pipe circle, and the impedance boundary is shown in figure 9;
and R, under the interface of the multi-physical field, setting an acoustic-structure boundary, and selecting the contact surface of a vibration component of the loudspeaker and air. The "acoustic-structure boundary" establishes a coupling relationship between "solid mechanics" and "pressure acoustics, frequency domain".
3) Defining material parameters: the parameters of the balance armature, the diaphragm, the soft iron, the magnetic steel and other components of the moving-iron type loudspeaker and the material parameters of the air are set, and the parameters mainly comprise Young modulus, density, poisson ratio, damping, dynamic viscosity, conductivity, dielectric constant and the like, and are shown in detail in FIG. 10. Wherein, the air material parameter comes from the COMSOL material library, and the relation of the material parameters such as dynamic viscosity and the like with the temperature change is COMSOL built-in.
4) Grid division: the mesh element type is designated as "free tetrahedral mesh", and the resulting finite element mesh model is shown in fig. 11. Grids are properly arranged in the pressure balance hole, the air domains of the front cavity and the rear cavity, the balance armature, the magnetic gap and the narrow air domain of the 711 coupler, so that the calculation result is more accurate. (2) Solution and post-processing
1) And solving the finite element model by adding a research of 'coil geometric analysis + small signal frequency domain disturbance'. Here, "coil geometry analysis" is mainly used to solve the coil characteristics of the moving-iron type speaker; the research is a built-in research method of COMSOL software;
2) After the setting is finished, the finite element model is solved, and the calculation process is finished by an algorithm built in COMSOL software;
3) And (3) post-treatment: the following simulation analysis results can be obtained by post-processing:
A. sound pressure level frequency response curve: firstly, adding a three-dimensional intercept point under a data set, inputting coordinates of a point position in the surface of a microphone, and setting the data set as a data set of research 1; then, adding a one-dimensional drawing group > dot diagram, setting a data set as a three-dimensional intercept point, inputting an expression of sound pressure level 'acpr.lp', and drawing to obtain a sound pressure level frequency response curve of the moving-iron loudspeaker, wherein the sound pressure level frequency response curve is shown in fig. 12;
B. impedance curve: adding a one-dimensional drawing group and global, selecting a data set, inputting an impedance expression, and drawing to obtain an impedance curve of the moving-iron type loudspeaker as shown in fig. 13; here, the speaker impedance Z (f) satisfies the relation of
Z0 (f) is impedance when induced electromotive force (generated by magnetic flux change in the voice coil due to armature position change) is not considered, U0 is external applied voltage, and U (x) is induced electromotive force generated in the coil by armature movement;
C. sound pressure distribution: adding a three-dimensional drawing group > volume 1', adding selection, setting a domain to be checked as a moving-iron type loudspeaker sound cavity, setting a data set and a frequency point to be checked, inputting a sound pressure expression acpr.p _ t, and drawing to obtain sound pressure distribution as shown in fig. 14;
D. sound pressure level distribution: the "three-dimensional drawing group > volume 1" is added, the data set of study 1 and the frequency point to be viewed are selected, the sound pressure level expression acpr.
The above embodiments are only used to illustrate the implementation process of the present invention and not to limit the technical solution described in the present invention. Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the present invention may be modified or replaced with equivalents, and all technical solutions and modifications thereof that do not depart from the spirit and scope of the present invention should be covered by the protection scope of the present invention.
Claims (3)
1. A numerical simulation analysis method for basic characteristics of a moving-iron type loudspeaker is characterized by comprising two parts, wherein the first part simulates and analyzes the influence of the displacement of a balanced armature on the electromotive force on a coil and the electromagnetic force on the armature; the second part is that on the basis of the first part, the basic characteristics of the moving-iron type loudspeaker are simulated and analyzed, wherein the basic characteristics comprise sound pressure level frequency response curve and impedance curve characteristics;
the simulation analysis method of the first part uses two physical field interfaces of 'solid mechanics' and 'magnetic field', and at least comprises the following steps:
(1) Establishing a finite element model
1) Establishing a geometric model: importing a geometric model of the moving-iron type loudspeaker into finite element analysis software, wherein the geometric model of the loudspeaker is drawn by adopting three-dimensional drawing software or is established by adopting a geometric modeling function of the finite element analysis software; after the geometric model is established, redundant points, lines, surfaces and bodies in the model need to be cleaned so as to improve the quality of the geometric model;
2) Setting physical fields and boundary conditions
A. Selecting a physical field corresponding domain of a 'magnetic field', wherein the corresponding domain comprises a domain corresponding to each component of the moving-iron loudspeaker and an air domain;
B. under the magnetic field, setting the material constitutive relation of the magnetic steel as residual magnetic flux density and setting a residual magnetic flux density parameter value;
C. under the magnetic field, setting the material constitutive relation of the magnetic yoke as a B-H curve, and introducing the B-H curve value of the magnetic yoke under the material parameters; the B-H curve is a parameter which is obtained by testing and describes the magnetic property of the soft magnetic material;
D. under the 'magnetic field', the material constitutive relation of the voice coil, the balance armature and the air part is set as 'relative magnetic conductivity';
E. selecting a physical field corresponding domain of 'solid mechanics', namely a balanced armature domain;
F. under the 'solid mechanics', the material constitutive relation of the balance armature is 'linear elastic material';
G. under the solid mechanics, a fixed constraint surface is arranged at the fixed position of the balance armature;
H. under "solid mechanics", setting the upper surface of the balanced armature in the magnetic gap to a parameterized "boundary force load", said parameterized boundary force load being denoted as FF;
I. under the 'solid mechanics', the symmetrical plane of the balance armature is set as a 'symmetrical' boundary;
J. selecting a 'moving grid' physical field corresponding domain which comprises a balanced armature domain and an air domain;
K. under the 'moving grid', setting an air domain as 'free deformation';
l, under the 'moving grid', setting the balanced armature as 'specified deformation', wherein the displacements of the specified grid in X, Y and the Z direction are u, v and w respectively;
m, under the 'moving grid', setting the outer surface of the balanced armature as 'specified grid displacement', wherein the displacements of the specified grid in X, Y and the Z direction are u, v and w respectively; the outer surface does not comprise a fixed surface and a symmetrical surface;
n, under the 'moving grid', setting the symmetrical plane of the air domain and the balanced armature as 'appointed grid displacement', and appointing the displacement in the normal direction as 0;
3) Defining material parameters: here, the material parameters of the moving-iron type loudspeaker need to be set respectively, including the material parameters of the balanced armature, the vibrating diaphragm and the soft iron structure, wherein the material parameters include young modulus, density, poisson ratio and damping;
4) Grid division: specifying the type and size of the grid cell, and dividing the grid: the size of the grid unit is set, and local grid refinement is carried out properly, so that the calculation result is more accurate;
(2) Solution and post-processing
1) Solving: by adopting steady-state research, the variation of the magnetic flux in the coil and the Maxwell stress tensor of the armature surface along with the armature displacement when the balanced armature is in different displacements is calculated; 2) And (5) post-processing results, namely obtaining the following results by adopting post-processing operation after the solution is completed: A. calculating the change relation of the induced electromotive force in the coil along with the displacement of the armature according to the change of the magnetic flux in the coil, and recording the change relation as U (x); B. calculating the variation relation of the electromagnetic force on the armature along with the displacement of the armature according to the Maxwell stress tensor of the surface of the armature, and recording the variation relation as F (x);
the simulation analysis method of the second part uses a pressure acoustic, frequency domain, magnetic field and solid mechanics physical field interface and an acoustic-structure boundary multi-physical field interface, and at least comprises the following steps:
(1) Establishing a finite element model
1) Building a geometric model
A. Establishing a geometric model of the loudspeaker: importing a geometric model of the moving-iron type loudspeaker into finite element analysis software, wherein the geometric model of the loudspeaker can be drawn by adopting three-dimensional drawing software or built by adopting a geometric modeling function of the finite element analysis software, and after the geometric model is built, redundant points, lines, surfaces and bodies in the model need to be cleaned so as to improve the quality of the geometric model;
B. establishing 711 an equivalent model of the acoustic cavity of the coupler: testing a sound pressure level frequency response curve of the moving-iron type loudspeaker in the 711 coupler, and establishing an equivalent model of a sound cavity of the 711 coupler, including a connecting pipe, for the simulation analysis method to be more universal and enabling the sound cavity to be correctly connected with the loudspeaker;
2) Setting physical fields and boundary conditions
A. Selecting a physical field corresponding domain of a 'magnetic field', wherein the corresponding domain comprises a domain corresponding to each component of the moving-iron loudspeaker and an air domain;
B. under the magnetic field, setting the material constitutive relation of the magnetic steel as residual magnetic flux density and setting a residual magnetic flux density parameter value;
C. under the magnetic field, setting the material constitutive relation of the magnetic yoke as a B-H curve, and introducing the B-H curve value of the magnetic yoke under the material parameters; the B-H curve is a parameter which is obtained by testing and describes the magnetic property of the soft magnetic material;
D. under the 'magnetic field', the material constitutive relation of the voice coil, the balance armature and the air part is set as 'relative permeability';
E. under the 'magnetic field', adding a 'coil' domain, inputting turns and wire diameter, and setting a 'harmonic disturbance voltage value' and 'geometric analysis' of the coil; the coil harmonic disturbance voltage value is U0-U (x), U0 is an external voltage, and U (x) is induced electromotive force generated in the coil by the movement of the armature;
F. under the 'magnetic field', an 'external current density', namely an induced current generated by cutting a magnetic induction line by the balance armature, is arranged on the balance armature;
G. under the magnetic field, setting force calculation for balancing the armature area, and calculating the stress tensor Wei Biaomian of the armature in the magnetic field;
H. selecting a physical field corresponding domain of 'solid mechanics', wherein the physical field corresponding domain comprises a balanced armature, a vibrating diaphragm and a linkage rod;
I. under the solid mechanics, the material constitutive relation of the balance armature, the vibrating diaphragm and the connecting rod is set as a linear elastic material, and the damping types and the damping values of the materials are set;
J. under the solid mechanics, a fixed constraint surface is arranged at the fixed position of the balance armature and the vibrating diaphragm;
K. under the condition of solid mechanics, setting the boundary load of the surface of the balanced armature, wherein the load type is set as the stress tensor of Max Wei Biaomian on the unit area;
l, under the 'solid mechanics', setting 'boundary load' for the upper surface of a balanced armature in a magnetic gap, wherein the load is F (x), namely considering the variation relation of Maxwell stress tensor of the surface of the armature along with the displacement of the armature;
m, under the 'solid mechanics', setting the symmetrical surfaces of the balance armature, the connecting rod and the vibrating diaphragm as 'symmetrical' boundaries;
n, selecting a physical field corresponding domain of 'pressure acoustics, frequency domain', wherein the corresponding domain comprises an air domain in a loudspeaker and an air domain in an 711 coupler sound cavity;
o. under "pressure acoustics, frequency domain", the narrow domain in which the pressure balance hole, the front cavity, and the 711 coupler are arranged is "narrow domain acoustics";
p. under "pressure acoustics, frequency domain", the microphone end face of 711 coupler is set to "impedance" boundary of "series coupling RCL", where R is equivalent acoustic resistance, C is equivalent acoustic compliance, and L is equivalent acoustic inertia;
q, under the conditions of pressure acoustics and frequency domain, setting the outer end face of the pressure balance hole as an impedance boundary of the tail end of the waveguide with the flange;
r, setting an acoustic-structure boundary under a multi-physical-field interface for coupling solid mechanics and a sound field;
3) Defining material parameters: setting material parameter values of a balance armature, a vibrating diaphragm, soft iron, a magnetic steel component and air of the moving-iron type loudspeaker, wherein the material parameter values mainly comprise Young modulus, density, poisson ratio, damping, dynamic viscosity, conductivity and dielectric constant;
4) Dividing the grid, namely, specifying the type of a grid unit to obtain a finite element grid model; grids are properly arranged in the pressure balance hole, the air domains of the front cavity and the rear cavity, the balance armature, the magnetic gap and the narrow air domain of the 711 coupler, so that the calculation result is more accurate;
(2) Solution and post-processing
1) Solving, in the simulation analysis of the moving-iron loudspeaker, the finite element model is solved by adopting the research of 'coil geometric analysis + small signal frequency domain disturbance';
2) And (4) performing result post-processing, namely performing post-processing operation after solving is completed to obtain the basic characteristics of the moving-iron type loudspeaker, wherein the basic characteristics mainly comprise: A. the sound pressure level frequency response curve of the moving-iron loudspeaker; B. the impedance curve of the moving-iron loudspeaker; C. sound pressure and sound pressure level distribution in the acoustic cavity; the post-processing operation is a conventional operation for obtaining results by finite element software.
2. The method of numerical simulation analysis of essential characteristics of a moving-iron speaker according to claim 1, wherein the geometry of the speaker, the material properties of the materials used for the components of the speaker, the constraints of the speaker, and the load conditions are known.
3. The method of claim 1, wherein the finite element analysis software comprises COMSOL or ANSYS finite element analysis software; the drawing software comprises SolidWorks or ProE drawing software.
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| CN112924012A (en) * | 2021-01-25 | 2021-06-08 | 中航华东光电（上海）有限公司 | Method for measuring acoustic parameters of closed small space |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102368281A (en) * | 2011-11-14 | 2012-03-07 | 浙江中科电声研发中心 | Numerical value simulating method for loudspeaker magnetic circuit system |
| CN103294871A (en) * | 2013-06-09 | 2013-09-11 | 嘉善恩益迪电声技术服务有限公司 | Numerical simulation analytical method of loudspeaker voice coil inductance nonlinear characteristic |
| CN103310052A (en) * | 2013-06-09 | 2013-09-18 | 嘉善恩益迪电声技术服务有限公司 | Numerical simulation analysis method for carrying out numerical simulation analysis on nonlinear characteristic of stiffness coefficient of centering disk of loudspeaker |
| CN104252559A (en) * | 2014-08-29 | 2014-12-31 | 浙江中科电声研发中心 | Numerical simulation analysis method for multi-field coupling of loudspeaker |
| CN105095609A (en) * | 2015-09-21 | 2015-11-25 | 武汉大学 | Transformer electromagnetic vibration noise calculating method based on finite element method |
| CN109145514A (en) * | 2018-09-30 | 2019-01-04 | 浙江中科电声研发中心 | A kind of Numerical Simulation Analysis method of loudspeaker distortions |
-
2019
- 2019-07-02 CN CN201910587524.8A patent/CN110427650B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102368281A (en) * | 2011-11-14 | 2012-03-07 | 浙江中科电声研发中心 | Numerical value simulating method for loudspeaker magnetic circuit system |
| CN103294871A (en) * | 2013-06-09 | 2013-09-11 | 嘉善恩益迪电声技术服务有限公司 | Numerical simulation analytical method of loudspeaker voice coil inductance nonlinear characteristic |
| CN103310052A (en) * | 2013-06-09 | 2013-09-18 | 嘉善恩益迪电声技术服务有限公司 | Numerical simulation analysis method for carrying out numerical simulation analysis on nonlinear characteristic of stiffness coefficient of centering disk of loudspeaker |
| CN104252559A (en) * | 2014-08-29 | 2014-12-31 | 浙江中科电声研发中心 | Numerical simulation analysis method for multi-field coupling of loudspeaker |
| CN105095609A (en) * | 2015-09-21 | 2015-11-25 | 武汉大学 | Transformer electromagnetic vibration noise calculating method based on finite element method |
| CN109145514A (en) * | 2018-09-30 | 2019-01-04 | 浙江中科电声研发中心 | A kind of Numerical Simulation Analysis method of loudspeaker distortions |
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