CN102052999A - Fixed joint surface unit area dynamic property identification experiment device and identification method thereof - Google Patents

Abstract

The invention relates to a fixed joint surface unit area dynamic property identification experiment device and an identification method thereof, belonging to the technical field of product structure optimal design in the development of numerical control machines. The fixed joint surface unit area dynamic property identification experiment device comprises a base (4), an experiment bottom block (3), an experiment gasket (2), an experiment connecting block (1), a drive execution module and the like. By adopting a structural form of respectively experimenting at both ends, an experiment platform with small-area complete contact is achieved, and the identification on unit area joint surface universal dynamic property parameters is finished. The experiment device and the identification method thereof provided by the invention have the advantages of providing basic theory data required by the optimization of a main structure of a whole machine, realizing dynamic analysis and optimal design on a structure without a model machine and having active actual significance in improving the processing precision and the product performance.

Description

Fixed combinating surface unit area dynamic perfromance identification experimental provision and recognition methods thereof

Technical field

The present invention relates to a kind of experimental provision, particularly a kind of fixed combinating surface unit area dynamic characteristic parameter identification experimental provision and recognition methods thereof under different materials, surfaceness, oil-containing medium and preload state belongs to the product main structure design optimizing field in the physical construction exploitation.

Background technology

The quiet dynamic quality of lathe main structure system becomes the key factor that properties of product improve.According to statistics, occurring on the lathe that vibration problem has more than 60% is to be derived from faying face, and damping value comes from the damping of joint portion more than 90%.Research to the quiet dynamic perfromance of faying face becomes at a high speed, the important topic of high-accuracy, efficient lathe research.Fixed combinating surface is the faying face form on basis in the lathe, being connected etc. of the conical surface of being connected of being connected of wherein organic bed box body and lathe bed, frame and support, main shaft and handle of a knife.And the dynamic perfromance of forming faying face has non-linear, the multifactor characteristics such as mechanical system of being correlated with, depending on, therefore with faying face from wherein separating a difficult problem that has just become faying face research.And experimental modal analysis is along with based on " the mechanical impedance tester " of binary channels tracking filtering technique with based on " frequency characteristic analyzer " of digital correlation technology, the development of " data collecting card " and reach its maturity and perfect.

Provide the fixed combinating surface parameter of versatility: the tangential rigidity and the damping of the normal stiffness of unit area and damping and unit area.The research of this experimental system is for the complete machine finite element analysis and the optimal design of lathe provides important faying face underlying parameter.Actual contact situation that also can the simulated machine tool faying face simultaneously is for this machine tool system provides faying face dynamic characteristic parameter accurately, as detecting the important parameter data of optimizing machine tool structure.

Summary of the invention

The purpose of this invention is to provide a kind of fixed combinating surface unit area dynamic perfromance identification experimental provision and recognition methods thereof, for the finite element analysis of machine tool structure, no model machine rapid Optimum provide required important faying face supplemental characteristic.The present invention adopts following technological means to realize:

A kind of fixed combinating surface unit area dynamic perfromance identification experimental provision, it is characterized in that: comprise pedestal, experiment sole piece, experiment pad, experiment contiguous block, drive execution module five parts, the whole symmetrical structure that adopts of described experimental provision experimentizes simultaneously, central plane with pedestal is the center left-right symmetric, the two ends of described pedestal are symmetrical structure, be connected by bolt with experiment porch, the two ends symmetrical structure can carry out the faying face dynamic experiment simultaneously; The experiment material of described experiment sole piece, described experiment contiguous block and roughness unanimity are the exchangeable part in the experimental provision, and experiment material, roughness, precompression and oil-containing medium constitute the kinds of experiments combination; The position in experiment hole, sole piece installation site is connected with pedestal by sunk screw according to the location arrangements of pedestal pilot hole; The experiment contiguous block designs for both wings, and with the geometric center place of guarantee effect center of gravity at four experiment pads, the experiment contiguous block is connected with the experiment sole piece by stud nut; Described experiment pad upper and lower surface integration does not contact with the experiment sole piece fully with the experiment contiguous block, and a kind of experiment composite type needs four, is evenly arranged on the experiment sole piece; Described driving execution module, comprise vibrator, reluctance head, test contiguous block, vibrator is connected with reluctance head by exciting rod, reluctance head is then pasted or is inhaled the surface of the normal direction center line that is attached to the experiment contiguous block or locates with the web joint side of the center of gravity level of testing pad, and the exciting force that is produced by vibrator acts on the experiment contiguous block; Described experimental provision also is provided with the Dynamic Signal processing module, and the Dynamic Signal processing module comprises acceleration transducer, charge amplifier, power amplifier, data acquisition unit, microcomputer; Reluctance head bonding or be adsorbed on the test contiguous block, acceleration transducer bonding or be adsorbed on the experiment sole piece or be arranged on the pedestal, acceleration transducer signals send data acquisition unit and microcomputer to handle through charge amplifier and power amplifier conditioning.

The machining precision height of the experiment pad of aforesaid fixed combinating surface unit area dynamic characteristic parameter identification experimental provision adopts finish-milling processing, and relative area is as far as possible little, and the thickness of experiment pad is 2mm, and area is 1cm ²

The recognition methods of said fixing faying face unit area dynamic perfromance identification experimental provision is as follows:

Step 1: the faying face equivalence of experimental provision being tested sole piece, experiment contiguous block and four experiment pad formations is 8 springs, and the theoretical model of 8 dampers is equivalent mass M with this experimental provision equivalence _e, equivalent stiffness K _e, equivalent damping is C _eSingle-mode system, the frequency response function H of the equivalent single-mode system of its sinusoidal excitation _e(w) suc as formula 1., formula 2. shown in

H _e(w)＝1/-M _ew ²+jwC _e+K _e ①

$H_e\left(w\right)=\frac{H_{X_e-X_{\mathrm{es}}}\left(w\right)}{1-{\mathrm{mw}}^2((M_e/m)\·H_{X_e-X_{\mathrm{es}}}\left(w\right)-H_{X_c}\left(w\right))}$ ②

In the formula: m is the master of the system quality of shaking, M _eBe equivalent mass, K _e, C _eBe the equivalent stiffness and the equivalent damping of the equivalent single-mode system of this theoretical model, X _eBe the equivalent displacement on the faying face place frequency domain on this theoretical model, X _EsBe the equivalent displacement on the following faying face frequency domain, X _cBe the displacement on the center of gravity place frequency domain,

Be respectively the frequency response function at equivalent faying face and center of gravity place;

Step 2: this experimental provision of sinusoidal excitation records the frequency response function at center of gravity place

Left faying face group place, right faying face group place, X with the experiment pad _eThe frequency response function at place is respectively

If single experiment pad is respectively K and C with the rigidity and the damping at the faying face place that the experiment sole piece constitutes, then the mechanical model of this experimental provision be formula 3. with formula 4.

$(\frac{K}{2}+\frac{K}{2})(x_1\left(t\right)-x_{1s}\left(t\right))+(\frac{K}{2}+\frac{K}{2})(x_2\left(t\right)-x_{2s}\left(t\right))=K_e(x_e\left(t\right)-x_{\mathrm{es}}\left(t\right))$ ③

$(\frac{K}{2}+\frac{K}{2})({\stackrel{\·}{x}}_1\left(t\right)-{\stackrel{\·}{x}}_{1s}\left(t\right))+(\frac{K}{2}+\frac{K}{2})({\stackrel{\·}{x}}_2\left(t\right)-{\stackrel{\·}{x}}_{2s}\left(t\right))=K_e({\stackrel{\·}{x}}_e\left(t\right)-{\stackrel{\·}{x}}_{\mathrm{es}}\left(t\right))$ ④

In the formula: x ₁(t) be the equivalent displacement on the faying face experiment contiguous block time domain in the left faying face group place, x _1s(t) be the equivalent displacement on the faying face experiment sole piece time domain under the left faying face group place, x ₂(t) be the equivalent displacement on the faying face experiment contiguous block time domain in the right faying face group place, x _2s(t) be the equivalent displacement on the faying face experiment sole piece time domain under the right faying face group place, x _e(t) be the equivalent displacement on the faying face place time domain on this theoretical model, x _Es(t) be the equivalent displacement on the following faying face time domain;

By formula 3., formula 4. obtain the rigidity at single experiment pad and the faying face place that constitutes of experiment sole piece and damping be respectively formula 5., formula 6.

$K=\frac{K_e{H}_{X_e-X_{\mathrm{es}}}\left(w\right)}{H_{X_1-X_{1s}}\left(w\right)+H_{X_2-X_{2s}}\left(w\right)}$ ⑤

$C=\frac{C_e{H}_{X_e-X_{\mathrm{es}}}\left(w\right)}{H_{X_1-X_{1s}}\left(w\right)+H_{X_2-X_{2s}}\left(w\right)}$ ⑥

Step 3: the area S by the experiment pad calculates unit area in conjunction with stiffness coefficient and ratio of damping K _nAnd C _n, promptly suc as formula 7., formula 8. shown in

K _n＝K/S ⑦

C _n＝C/S ⑧。

The present invention has outstanding advantage at faying face rigidity and ratio of damping and prior art:

(1) experimental provision is simple and reliable, and is easy for installation, and two ends symmetrical structure form can be carried out the different experiment of two states simultaneously, saved the time of experiment.Realize normal direction and tangential exciting experiment under the different pretightning forces, obtained normal direction and tangential rigidity and ratio of damping;

(2) usable floor area is 1cm ²The experiment pad, realize contact fully, obtain the dynamic characteristic parameter of unit area, realized the identification of universalization dynamic characteristic parameter.For theoretical analysis provides the most basic experimental data.Also can carry out large-area experiment simultaneously.Obtain the dynamic characteristic parameter of actual contact state;

(3) experiment sole piece, experiment pad and experiment web joint are corresponding one by one, and exchangeable part has guaranteed the precision and the rationality of experiment.The faying face place is the frequency response function of vibration relatively, has got rid of the influence of experimental provision other parts to main part;

Description of drawings

Fig. 1 is the experimental provision wiring layout;

Fig. 2 is an experiment device schematic diagram;

Among the figure 1, the experiment web joint, 2, the experiment pad, 3, the experiment sole piece, 4, pedestal, 5, reluctance head, 6, acceleration transducer, 2A, left faying face group, 2B, right faying face group, A, vibrator, B1, charge amplifier, B2, power amplifier, C, data acquisition unit, D, microcomputer.

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail.

Figure 1 shows that experimental provision of the present invention, the whole symmetrical structure that adopts of fixed combinating surface unit area dynamic perfromance recognition device carries out the experiment of two groups of states simultaneously, central plane with pedestal 4 is the center left-right symmetric, comprises pedestal 4, experiment sole piece 3, experiment pad 2, experiment contiguous block 1, drives execution module five parts.

Pedestal 4 is the symmetrical structures that two ends are the same, the high 50mm of projective table type structure at its two ends, and the design of pedestal 4 and coupling stiffness have guaranteed greater than the requirement of faying face rigidity more than 5 times.The two ends symmetrical structure can carry out the experiment under the different conditions simultaneously, comprises the faying face material, whether the oil-containing medium is arranged, the combination of test condition such as different precompression, faying face roughness, and pedestal 4 is fixed by bolts on the test platform; Experiment sole piece 3 is made according to different materials, different roughness, becomes the exchangeable part in the experimental provision, and the position in its hole, installation site is connected with pedestal 4 by sunk screw according to the location arrangements of pedestal 4 pilot holes; The 2 whole finish-milling processing of experiment pad, area 1cm ²Thickness is 2mm, guarantee and test sole piece 3 and test contacting fully of contiguous block 1, can make for various materials, four of a kind of material types, be evenly arranged on the experiment sole piece 3, the both wings design of experiment contiguous block 1 makes its effect center of gravity at the geometric center place of four experiment pads 2, is connected with experiment sole piece 3 by bolt; Drive execution module, form by vibrator A, reluctance head 5, test contiguous block 1, vibrator A is connected with reluctance head 5 by exciting rod, 5 of reluctance heads paste or inhale the normal direction center line that is attached to experiment contiguous block 1 the surface or with the place, web joint side of the center of gravity level of experiment pad 2, the exciting force that is produced by vibrator A acts on the experiment contiguous block on 1; The dynamic perfromance recognition system also is provided with the Dynamic Signal processing module, and the Dynamic Signal processing module comprises acceleration transducer 6, charge amplifier B1, power amplifier B2, data acquisition unit C, microcomputer D.Acceleration transducer 6 bonds respectively or is adsorbed on the test contiguous block 1, on the pedestal 4, and its signal send data acquisition unit C and microcomputer D to handle through charge amplifier B1 and power amplifier B2 conditioning.

The principle of work of fixed combinating surface unit area dynamic characteristic parameter recognition system and step are as shown in Figure 3

1) this experimental provision experiment sole piece 3, experiment contiguous block 1 are 8 springs with the faying face equivalences of four experiment pad 2 formations, the theoretical model of 8 dampers as shown in Figure 2, equivalence is equivalent mass M _e, equivalent stiffness K _e, equivalent damping is C _ePilot system.Its mechanical model be formula 9.

$m{\stackrel{\·\·}{x}}_c+C_e({\stackrel{\·}{x}}_e\left(t\right)-{\stackrel{\·}{x}}_{\mathrm{es}}\left(t\right))+K_e(x_e\left(t\right)-x_{\mathrm{es}}\left(t\right))=F\left(t\right)$ ⑨

2) reluctance head 5 and acceleration transducer 6 are fixed, A slings with vibrator, and exciting rod is aimed at reluctance head 5, and sinusoidal excitation signal acts on the vibrator through power amplifier B2.Test the frequency response function at the center of gravity place of nursing one's health by charge amplifier B1 by microcomputer D control

With left faying face group 2A place, right faying face group 2B place, X _eThe frequency response function at place

3) the frequency response function H of the equivalent single-mode system of its sinusoidal excitation _e(w) suc as formula 1., 2. shown in, the spectrogram of equivalent single-mode system thus is according to the natural frequency f of peak resonance recognition system _nObtain equivalent stiffness K _eAnd the half-power bandwidth Δ f of half-power band bandwidth method of identification obtains equivalent damping C _eBe respectively K _e=M _e(2 π f _n), C _e=2 π M _eΔ f;

4) 5., 6. obtain single pad and faying face rigidity and damping K and C that experiment sole piece 3 constitutes according to formula, 7., 8. try to achieve the rigidity and the damping K of unit area faying face again by formula _n, C _n

5) faying face under tangential or other state is carried out exciting, repeat above step.

The above only is an an example of the present invention, and we also can carry out some conversion to experimental provision, to be applied to other dynamic perfromance identification of faying face.As long as the Design of Mechanical Structure thought of its dynamic perfromance recognition device and whole control thought all should be considered as the included scope of the present invention with the unanimity that the present invention narrated.

Claims (3)

1. fixed combinating surface unit area dynamic perfromance is discerned experimental provision, it is characterized in that: comprise pedestal (4), experiment sole piece (3), experiment pad (2), experiment contiguous block (1), drive execution module five parts, the whole symmetrical structure that adopts of described experimental provision experimentizes simultaneously, central plane with pedestal (4) is the center left-right symmetric, the two ends of described pedestal (4) are symmetrical structure, be connected by bolt with experiment porch, the two ends symmetrical structure can carry out the faying face dynamic experiment simultaneously; The experiment material of described experiment sole piece (3), described experiment contiguous block (1) and roughness unanimity are the exchangeable part in the experimental provision, and experiment material, roughness, precompression and oil-containing medium constitute the kinds of experiments combination; The position in experiment sole piece (3) hole, installation site is connected with pedestal (4) by sunk screw according to the location arrangements of pedestal (4) pilot hole; Experiment contiguous block (1) is for both wings design, and with the geometric center place of guarantee effect center of gravity at four experiment pads (2), experiment contiguous block (1) is connected with experiment sole piece (3) by stud nut; Described experiment pad (2) upper and lower surface integration does not contact with experiment sole piece (3) fully with experiment contiguous block (1), and a kind of experiment composite type needs four, is evenly arranged on the experiment sole piece (3); Described driving execution module, comprise vibrator (A), reluctance head (5), test contiguous block (1), vibrator (A) is connected with reluctance head (5) by exciting rod, reluctance head (5) is then pasted or is inhaled the surface of the normal direction center line that is attached to experiment contiguous block (1) or locates with the web joint side of the center of gravity level of testing pad (2), and the exciting force that is produced by vibrator (A) acts on the experiment contiguous block (1); Described experimental provision also is provided with the Dynamic Signal processing module, and the Dynamic Signal processing module comprises acceleration transducer (6), charge amplifier (B1), power amplifier (B2), data acquisition unit (C), microcomputer (D); Reluctance head (5) bonds or is adsorbed on the test contiguous block (1), acceleration transducer (6) bonds or is adsorbed on experiment sole piece (3) and goes up or be arranged on the pedestal (4), acceleration transducer (6) signal send data acquisition unit (C) and microcomputer (D) to handle through charge amplifier (B1) and power amplifier (B2) conditioning.

2. fixed combinating surface unit area dynamic perfromance identification experimental provision according to claim 1, it is characterized in that: experiment pad (2) adopts finish-milling processing, and thickness is 2mm, and area is 1cm ²

3. recognition methods of fixed combinating surface unit area dynamic perfromance identification experimental provision according to claim 1, it is characterized in that: step is as follows:

Step 1: the faying face equivalences of experimental provision being tested sole piece (3), experiment contiguous block (1) and four experiment pads (2) formation are 8 springs, and the theoretical model of 8 dampers is equivalent mass M with this experimental provision equivalence _e, equivalent stiffness K _e, equivalent damping is C _eSingle-mode system, the frequency response function H of the equivalent single-mode system of its sinusoidal excitation _e(w) suc as formula 1., formula 2. shown in

H _e(w)＝１/-M _ew ²+jwC _e+K _e ①

$H_e\left(w\right)=\frac{H_{X_e-X_{\mathrm{es}}}\left(w\right)}{1-{\mathrm{mw}}^2((M_e/m)\·H_{X_e-X_{\mathrm{es}}}\left(w\right)-H_{X_c}\left(w\right))}$ ②

In the formula: m is the master of the system quality of shaking, M _eBe equivalent mass, K _e, C _eBe the equivalent stiffness and the equivalent damping of the equivalent single-mode system of this theoretical model, X _eBe the equivalent displacement at faying face place on this theoretical model, X _EsBe the equivalent displacement of following faying face, X _cBe the displacement at center of gravity place,

Be respectively the frequency response function at equivalent faying face and center of gravity place;

Step 2: this experimental provision of sinusoidal excitation records the frequency response function at center of gravity place With the experiment pad (2) left faying face group (2A) locate, right faying face group (2B) is located, X _eThe frequency response function at place is respectively

If single experiment pad (2) is respectively K and C with the rigidity and the damping at the faying face place that experiment sole piece (3) constitutes, then the mechanical model of this experimental provision be formula 3. with formula 4.

$(\frac{K}{2}+\frac{K}{2})(x_1\left(t\right)-x_{1s}\left(t\right))+(\frac{K}{2}+\frac{K}{2})(x_2\left(t\right)-x_{2s}\left(t\right))=K_e(x_e\left(t\right)-x_{\mathrm{es}}\left(t\right))$ ③

$(\frac{K}{2}+\frac{K}{2})({\stackrel{\·}{x}}_1\left(t\right)-{\stackrel{\·}{x}}_{1s}\left(t\right))+(\frac{K}{2}+\frac{K}{2})({\stackrel{\·}{x}}_2\left(t\right)-{\stackrel{\·}{x}}_{2s}\left(t\right))=K_e({\stackrel{\·}{x}}_e\left(t\right)-{\stackrel{\·}{x}}_{\mathrm{es}}\left(t\right))$ ④

In the formula: x ₁(t) be that left faying face group (2A) is located the equivalent displacement on faying face experiment contiguous block (1) time domain, x _1s(t) be that left faying face group (2A) is located down the equivalent displacement on faying face experiment sole piece (3) time domain, x ₂(t) be that right faying face group (2B) is located the equivalent displacement on faying face experiment contiguous block (1) time domain, x _2s(t) be that right faying face group (2B) is located down the equivalent displacement on faying face experiment sole piece (3) time domain, x _e(t) be the equivalent displacement on the faying face place time domain on this theoretical model, x _Es(t) be the equivalent displacement on the following faying face time domain;

By formula 3., formula 4. obtain the rigidity at the faying face place that single experiment pad (2) and experiment sole piece (3) constitute and damping be respectively formula 5., formula 6.

$K=\frac{K_e{H}_{X_e-X_{\mathrm{es}}}\left(w\right)}{H_{X_1-X_{1s}}\left(w\right)+H_{X_2-X_{2s}}\left(w\right)}$ ⑤

$C=\frac{C_e{H}_{X_e-X_{\mathrm{es}}}\left(w\right)}{H_{X_1-X_{1s}}\left(w\right)+H_{X_2-X_{2s}}\left(w\right)}$ ⑥

Step 3: the area S by experiment pad (2) calculates unit area in conjunction with stiffness coefficient and ratio of damping K _nAnd C _n, promptly suc as formula 7., formula 8. shown in

K _n＝K/S ⑦

C _n＝C/S ⑧。

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