CN107203669A - A kind of Reverse optimization design method of MR damper - Google Patents

Abstract

The invention discloses a reverse optimization design method of a magneto-rheological damper. By selecting the required maximum damping force and adjustable coefficient, the method unifies the geometric design and the magnetic circuit design for reverse optimization design until The magnetorheological damper meets the required maximum damping force and adjustable coefficient in a relatively small size; among them, the geometric design uses MATLAB simulation software to calculate the geometric design target value, and the magnetic circuit design uses ANSYS finite element simulation to calculate the magnetic circuit design target value. The reverse optimization design method of the present invention not only satisfies the accuracy of the spatial magnetic field strength solution in the magnetic circuit design, but also fully considers the interrelationship between the geometric design and the magnetic circuit design, effectively avoiding premature magnetic saturation or magnetic The waste of road materials; this method has strong operability, and provides theoretical guidance for the design of magnetorheological dampers, which is convenient for its engineering application and promotion.

Description

A Reverse Optimal Design Method for Magnetorheological Damper

technical field

The invention relates to a reverse optimization design method of a magneto-rheological damper that can be used in the field of intelligent control.

Background technique

In recent years, there have been more and more researches on the use of vibration control technology for engineering structures to mitigate earthquake and strong wind disasters, and more and more specific technical means have been widely used in practical projects. Structural vibration control refers to attaching control components and control devices to the structure, passively or actively exerting a set of control forces on the structure when the structure vibrates, reducing or inhibiting the dynamic response of the structure, so as to meet the safety, usability and safety of the structure. comfort requirements.

Magneto-rheological damper is a representative of semi-active control devices in structural vibration control. It has the advantages of low energy consumption, large output, fast response speed, continuously adjustable damping force, etc., and can achieve better vibration control effects. Obviously, a convenient and effective design method for magnetorheological dampers is very important for its fabrication and engineering applications. At present, the basic idea of designing a magneto-rheological damper is roughly as follows: firstly, the geometric parameters of the damper are designed according to the maximum damping force of the damper; Parameter size, using the magnetic circuit Ohm's law for magnetic circuit design. Although this design idea is feasible, the design process separates the geometric design from the magnetic circuit design and fails to fully consider the interrelationship between the two. In response to the above problems, some scholars introduced magnetic circuit optimization to integrate magnetic circuit design and geometric design, and proposed a simplified design method for shear valve magneto-rheological dampers; however, the magnetic circuit part still uses the magnetic circuit ohm However, the combined structure of ferromagnets is relatively complex, so it is difficult to obtain an accurate analytical solution of the spatial magnetic field strength after electrification. Some scholars use finite elements to accurately simulate the magnetic field, take the maximum damping force and adjustable coefficient as the optimization goal, and use the multi-objective genetic algorithm to optimize the design of the magnetorheological damper; but the objective function is to maximize the maximum damping force and make the The adjustable coefficient is the largest, and in the actual engineering vibration reduction design, the reverse parameter optimization design is usually carried out under the condition of given the required maximum damping force and adjustable coefficient, so that the damper can meet the design requirements in a smaller size. Therefore, innovation must be sought on the basis of the existing design methods of magneto-rheological dampers.

Contents of the invention

Purpose of the invention: The technical problem to be solved by the present invention is to provide a reverse optimization design method of a magneto-rheological damper, so that the damper can meet the given maximum damping force and adjustable coefficient requirements in a smaller size.

Summary of the invention: In order to solve the above technical problems, the technical means adopted in the present invention are:

A reverse optimization design method of magnetorheological damper, the method unifies geometric design and magnetic circuit design by determining the required maximum damping force and adjustable coefficient, and carries out reverse optimization design until the magnetorheological damper The required maximum damping force and adjustable coefficient are met under a relatively small size; among them, the geometric design uses MATLAB simulation software to calculate the geometric design target value, and the magnetic circuit design uses ANSYS finite element simulation to calculate the magnetic circuit design target value.

The inventive method specifically comprises the steps:

Step 1, select the design target value of the magneto-rheological damper: maximum damping force U ^* and adjustable coefficient β ₀ ;

Step 2. Determine the maximum speed of the required damper piston rod according to the actual vibration situation Then combine the selected magnetorheological fluid and magnetic circuit material to determine the maximum shear yield strength τ _y corresponding to the working point of the magnetorheological fluid, and the zero-field viscosity η;

Step 3, according to the maximum damping force U ^* determined in step 1, calculate the required piston rod diameter d and the strength limit of the outer cylinder thickness t according to the mechanical design specifications and material mechanical properties;

Step 4, determine the magnetic permeability characteristics of each material and find the required magnetic induction intensity B ₀ at the working gap of the magnetic circuit according to the maximum shear yield strength τ _y selected in step 2;

Step 5, perform geometric design according to the strength limit value of the piston rod diameter d determined in step 3;

Step 6, carry out magnetic circuit design according to the strength limit value of the outer cylinder barrel thickness t determined in step 3 and the required magnetic induction intensity B _at the working gap of the magnetic circuit determined in step 4;

Step 7. Determine whether the designed geometric parameters and magnetic circuit parameters meet the requirements. If not, repeat steps 5 to 6 until the geometric parameters and magnetic circuit parameters reach the minimum size and meet the maximum design damping force U ^* determined in step 1. And adjustable coefficient β ₀ requirements.

Wherein, in step 5, the design steps of the geometric design include: (1) preliminary selection of geometric dimension parameters piston diameter D, piston rod diameter d, working gap width h and piston effective length L; (2) utilizing MATLAB simulation software to calculate The maximum damping force and adjustable coefficient obtained under the currently selected initial parameters; (3) compare the value obtained in (2) with the design target value, if the design requirements are not met, re-select the geometric size parameters, and repeat (1) ~(3), until the value obtained by simulation calculation meets the design requirements; (4) When the value obtained by simulation calculation meets the design requirements, then judge whether the set initial parameters can be further reduced, and if so, select a smaller value value, repeat steps (1) to (4), otherwise select the set parameters as the design result.

Wherein, in step 6, the design steps of the magnetic circuit design include: (1) according to the geometric design results, preliminarily select the number of turns N of the fixed coil, the thickness t of the outer cylinder, the length a and the width b of the groove; (2) use Magnetic circuit ANSYS finite element simulation to calculate the average magnetic induction intensity at the working gap (3) Judging whether the length a and width b of the excavation are less than the limit value, if they are satisfied, go to the next step, otherwise, re-design the geometry and go to steps (1)~(3); (4) Judging the working gap in step (2) average magnetic induction Whether it is greater than or equal to the magnetic induction intensity B ₀ at the working gap of the selected magnetic circuit, if it is satisfied, proceed to the next step, otherwise repeat steps (1)~(4); (5) judge whether the set initial parameters can be further reduced , if possible, select a smaller value and repeat steps (1) to (5), otherwise, select the set parameter as the design result.

Among them, considering the mechanical characteristics requirements of the length a and width b of the groove, the limit value of the length a of the groove is taken as a quarter of the length of the piston head, and the limit value of the width b of the groove is taken as the difference between the diameter of the piston head and the diameter of the piston rod Half.

Wherein, the specific analysis process of the ANSYS finite element simulation is: (1) select the two-dimensional static analysis type, and the unit selects the two-dimensional 8-node quadrilateral solid element Plane53; (2) establish the piston, The finite element model of the cylinder, gap magnetorheological fluid, coil, air and sealing epoxy resin; (3) apply the boundary condition parallel to the magnetic flux on the outer boundary line of the model, and divide the grid; (4) apply it in the form of current density Excitation, statically solve the model; (5) enter the post-processing, check the magnetic field strength data, and carry out the average magnetic induction intensity at the working gap calculation.

Wherein, the calculation formulas of the maximum damping force and the adjustable coefficient are respectively:

F _{MRD, max} = F _τ + F _η + F _p0 ;

In the formula, p ₀ =1.2 MPa.

Compared with the prior art, the technical solution of the present invention has the beneficial effects of:

Firstly, the method of the present invention performs reverse optimization design on the magneto-rheological damper through unified geometric design and magnetic circuit design, so that the damper can meet the given maximum damping force and adjustable coefficient requirements in a smaller size; at the same time, using MATLAB and ANSYS respectively simulate and calculate the target values in the geometric design and magnetic circuit design, repeated trial calculations, and comprehensive comparisons until the requirements are met. This not only meets the accuracy of the space magnetic field strength solution in the magnetic circuit design, but also fully considers the geometric design and The interrelationship between magnetic circuit designs effectively avoids premature magnetic saturation or waste of magnetic circuit materials; secondly, the design process adapts to the known maximum damping force and adjustable coefficient in the actual engineering structure vibration reduction design. The reverse design of the flow requirements of the magneto-rheological damper achieves engineering economy; finally, the method of the present invention has strong operability, provides theoretical guidance for the design of the magnetorheological damper, and facilitates its engineering application and promotion.

Description of drawings

Fig. 1 is the flowchart of the reverse optimal design method of magneto-rheological damper of the present invention;

Figure 2 is the B-H curve of the magnetic circuit material;

Fig. 3 is the zero-field viscosity-velocity curve of magnetorheological fluid;

Fig. 4 is the B-H curve of magnetorheological fluid;

Fig. 5 is the τ _y -B curve of the magnetorheological fluid.

detailed description

The present invention can be better understood from the following examples. However, those skilled in the art can easily understand that the content described in the embodiments is only for illustrating the present invention, and should not and will not limit the present invention described in the claims.

As shown in Figure 1, the reverse optimal design method of the magneto-rheological damper of the present invention, under the condition of given the required maximum damping force and adjustable coefficient, unifies the geometric design and the magnetic circuit design to optimize the design, So that the magneto-rheological damper can meet the required maximum damping force and adjustable coefficient in a smaller size.

Combining the characteristics of shock absorption of civil engineering structures and the unified optimization design process, this embodiment designs a magneto-rheological damper with a damping force of 1.5KN, that is, the maximum damping force U ^* = 1.5KN, and the maximum working speed of the damper is 25mm/s, and the adjustable coefficient β ₀ is 1.2. The piston and piston rod are made of DT ₄ electrical pure iron, and the piston and piston rod are connected as a whole, and the rest of the components are made of 45 ^# steel. Figure 2 shows the BH curve of the two. The enameled wire is a copper wire with a diameter of 1mm. The relative magnetic permeability of enameled wire, air and epoxy resin is taken as 1 during finite element simulation. The magnetorheological fluid can be the magnetorheological fluid on the market, but the CB22 magnetorheological fluid developed by our research group is preferred. Among them, Figure 3 is the zero-field viscosity-velocity curve of the magnetorheological fluid at 25°C. Fig. 4 is the BH curve of the magnetorheological fluid, and Fig. 5 is the τ _y -B curve of the magnetorheological fluid. The magnetic induction intensity B=300mT is measured, and the point in the magnetorheological fluid τ _y -B curve when the magnetic induction intensity is 0.3T is the working point of the magnetorheological fluid, so the magnetic induction intensity B ₀ at the working gap in the magnetic circuit design is 0.3 T, the corresponding maximum shear yield strength τ _y at this time is 4.64KPa. According to the relationship curve of zero-field viscosity-velocity fitted in Fig. 3, the zero-field viscosity η under the working maximum speed of 25mm/s of the damper is calculated to be 1.45pa.s. Considering that the magnetic saturation current is too small, the adjustment range of the current is small, and the magnetic saturation current is too large, the damper power is large, and it is easy to get hot, so I _max is selected as 1.5A in comprehensive consideration. According to mechanical design specifications, material mechanical properties and damper stress, the strength limit of piston rod diameter d is 10.23mm (piston rod opening 4mm), and the strength limit of outer cylinder thickness t is 3.05mm.

According to the flow chart shown in Figure 1, the unified optimization design of the magnetorheological damper is carried out. When designing the magnetorheological damper, the design goal is first given, and then the geometric design is carried out according to the properties of the selected materials, and then the geometric design is carried out. Based on the magnetic circuit design, compare the design parameters to get the final parameter design value. The whole process is based on the exchange of the simulation results of MATLAB and ANSYS, and the calculated target values of the geometric design and magnetic circuit design, if they do not meet the design requirements, go back to re-take, simulate, and compare until the design requirements are met.

The calculation formula of maximum damping force and adjustable coefficient in the inventive method is as follows:

In the formula, p ₀ =1.2 MPa.

The specific analysis process of magnetic circuit ANSYS finite element simulation in the method of the present invention is: (1) select the two-dimensional static analysis type for use, and the unit selects the two-dimensional 8-node quadrilateral solid element Plane53 for use; (2) establish respectively according to the magnetic permeability characteristic of known material The finite element model of the piston, cylinder, gap magnetorheological fluid, coil, air and sealing epoxy resin; (3) apply the boundary condition parallel to the magnetic flux on the outer boundary line of the model, and divide the grid; (4) use the current density ( Apply excitation in the form of dividing the total current by the area of the coil) to solve the model statically; (5) enter the post-processing, check the magnetic field intensity data, and calculate the average magnetic induction intensity at the working gap.

It can be seen that the unified optimization design process of magnetorheological dampers is actually a process of continuously adjusting parameters until the design requirements are met. After repeating the above design process and considering the actual engineering conditions, the parameter size of the damper is finally determined, see Table 1 for details. At this time, the calculated target value of the damper is: F _{MRD, max} = 1557.17N, β ₀ = 1.23, The method of the invention has strong operability, provides theoretical guidance for the design of the magneto-rheological damper, and is convenient for its engineering application and popularization.

Table 1 Main parameters and dimensions of magnetorheological dampers

Apparently, the above-mentioned embodiments are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. And these obvious changes or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims (7)

1. a kind of Reverse optimization design method of MR damper, it is characterised in that：This method passes through the maximum needed for determination Damping force and adjustability coefficients, geometry designs and magnetic Circuit Design are united and carry out Reverse optimization design, until magnetorheological damping Device meets required maximum damping force and adjustability coefficients under relatively small size；Wherein, geometry designs are emulated using MATLAB Software computational geometry design object value, magnetic Circuit Design utilizes ANSYS finite element stimulation magnetic Circuit Design desired values.

2. the Reverse optimization design method of MR damper according to claim 1, it is characterised in that：Specifically include as Lower step：

Step 1, the design object value of MR damper is selected：Maximum damping force U^*With adjustability coefficients β₀；

Step 2, the maximal rate of damper rod needed for being determined according to actual vibration situationIn conjunction with the magnetorheological of selection Liquid and magnetic circuit material determine the corresponding maximum shear yield strength τ in magnetic flow liquid operating point_yWith null field viscosities il；

Step 3, the maximum damping force U determined according to step 1^*, it is living needed for being calculated according to Machine Design specification and characteristic of material mechanics Stopper rod diameter d and outer shell barrel thickness t intensity limit value；

Step 4, the permeance of each material is determined and according to the maximum shear yield strength τ selected in step 2_ySearch magnetic circuit Magnetic induction density B is needed at working clearance₀；

Step 5, the diameter of piston rod d determined according to step 3 intensity limit value carries out geometry designs；

Step 6, institute's need at the magnetic circuit working clearance that the outer shell barrel thickness t determined according to step 3 intensity limit value and step 4 is determined Magnetic induction density B₀Carry out magnetic Circuit Design；

Step 7, judge whether the geometric parameter and magnetic circuit parameters of design meet requirement, the repeat step 5 if being unsatisfactory for requiring ~6, until geometric parameter and magnetic circuit parameters reach minimum dimension and meet the design maximum damping force U determined in step 1^*With can Adjust factor beta₀Requirement.

3. the Reverse optimization design method of MR damper according to claim 2, it is characterised in that：In step 5, institute Stating the design procedure of geometry designs includes：(1) it is preliminary to choose physical dimension parameter piston diameter D, diameter of piston rod d, workplace Gap width h and piston effective length L；(2) calculated and obtained most under the initial parameter currently chosen using MATLAB simulation softwares Big damping force and adjustability coefficients；(3) numerical value and by (2) obtained is compared with design object value, if being unsatisfactory for design requirement, again Physical dimension parameter is chosen, (1)~(3) are repeated, untill numerical value that simulation calculation is obtained meets design requirement；(4) when The numerical value that simulation calculation is obtained is met after design requirement, then judges whether the initial parameter of setting can further reduce, if Smaller value repeat step (1)~(4) can be then chosen again, otherwise choose the parameter set as design result.

4. the Reverse optimization design method of MR damper according to claim 2, it is characterised in that：In step 6, institute Stating the design procedure of magnetic Circuit Design includes：(1) according to geometry designs result, it is preliminary choose determine turn number N, outer shell barrel thickness t, Grooving length a and width b；(2) average magnetic induction intensity at the ANSYS finite element stimulation working clearances is utilized(3) judge Whether grooving length a and width b is less than limit value, carries out next step if meeting, otherwise re-starts geometry designs and carry out Step (1)~(3)；(4) average magnetic induction intensity at the working clearance in judgment step (2)Whether selected magnetic is more than or equal to Magnetic induction density B at the working clearance of road₀, if it is satisfied, then carrying out next step, otherwise repeat step (1)~(4)；(5) judge to set Whether fixed initial parameter can further reduce, if can if choose smaller value repeat step (1)~(5) again, otherwise The parameter set is chosen as design result.

5. the Reverse optimization design method of MR damper according to claim 4, it is characterised in that：Consider that grooving is long A and width b mechanical characteristic requirement is spent, grooving length a limit value takes a quarter of piston head length, grooving width b limit Value takes 1/2nd of piston head diameter and diameter of piston rod difference.

6. the Reverse optimization design method of MR damper according to claim 4, it is characterised in that：The ANSYS The concrete analysis process of finite element simulation is：(1) two-dimensional static analysis type is selected, unit is real from two-dimentional 8 Node Quadrilateral Element Body unit Plane53；(2) piston, cylinder barrel, gap magnetic flow liquid, coil, sky are set up according to the permeance of known materials respectively Gas and the FEM model of sealing epoxy resin part；(3) boundary line applies the parallel boundary condition of magnetic flux outside model, draws Subnetting lattice；(4) apply excitation in the form of current density, static solution is carried out to the model；(5) enter post processing, check magnetic Field strength degrees of data, is operated gap location average magnetic induction intensityCalculating.

7. the Reverse optimization design method of MR damper according to claim 1 or 2, it is characterised in that：It is described most Big damping force and the calculation formula of adjustability coefficients are as follows：

<mrow> <msub> <mi>F</mi> <mrow> <mi>M</mi> <mi>R</mi> <mi>D</mi> <mo>,</mo> <mi>max</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>F</mi> <mi>&amp;tau;</mi> </msub> <mo>+</mo> <msub> <mi>F</mi> <mi>&amp;eta;</mi> </msub> <mo>+</mo> <msub> <mi>F</mi> <msub> <mi>p</mi> <mn>0</mn> </msub> </msub> <mo>;</mo> </mrow>

<mrow> <mi>&amp;beta;</mi> <mo>=</mo> <mfrac> <msub> <mi>F</mi> <mi>&amp;tau;</mi> </msub> <mrow> <msub> <mi>F</mi> <mi>&amp;eta;</mi> </msub> <mo>+</mo> <msub> <mi>F</mi> <msub> <mi>p</mi> <mn>0</mn> </msub> </msub> </mrow> </mfrac> <mo>;</mo> </mrow>

In formula, p₀=1.2Mpa.