CN103308333A - Method for testing dynamic stiffness of vibration isolator - Google Patents

Abstract

The invention relates to a method for testing the dynamic stiffness of a vibration isolator, comprising the following steps of (1) arranging an acceleration sensor in a coupling site via a mode that a vibration structure is connected in a coupling way by the vibration isolator; (2) directly measuring system level frequency response functions; and (3) directly calculating according to the measured system level frequency response functions to obtain the dynamic stiffness Kc of the vibration isolator. Compared with an existing technique, the method for testing the dynamic stiffness of the vibration isolator has the advantages of measurement without dismantling equipment, good project practicability and simplicity, precision, feasibility and the like.

Description

A kind of vibration isolator dynamic stiffness method of testing

Technical field

The present invention relates to the mechanical vibration technical field of measurement and test, especially relate to a kind of vibration isolator dynamic stiffness method of testing.

Background technology

Along with the raising of people's environmental consciousness, control is had higher requirement to the vibration and noise in the productive life, the with serious pollution fields of vibration and noise such as particularly communications and transportation, the manufacturing, building, and how vibration isolation becomes the problem that needs are considered.The appropriate combination of the normally passive flexible member of vibration isolator and damping element, thereby have certain rigidity and damping.As the critical component of vibration and noise reducing system, the dynamic property of vibration isolator is directly connected to vibration isolating effect.Dynamic stiffness is an important indicator of vibration isolator evaluation of dynamic, has a great impact for the vibration isolator anti-vibration performance.

The at present test of vibration isolator dynamic stiffness mainly contains two kinds of methods: power-displacement method and acceleration method.Power-displacement method is the method for testing of comparatively commonly using, and this method test philosophy is simple and precision is high, but requires to use expensive electro-hydraulic servo high frequency actuator, rigidly fixes the end technical requirement in the experiment also higher, simultaneously the test frequency narrow range.Acceleration method needn't be considered the problems such as the rigidity of stiff end and system resonance, also enlarged the frequency range of dynamic characteristic test simultaneously, but precision does not have power-displacement method high.

Summary of the invention

Purpose of the present invention is exactly to provide a kind of vibration isolator dynamic stiffness method of testing for the defective that overcomes above-mentioned prior art existence.

Purpose of the present invention can be achieved through the following technical solutions:

A kind of vibration isolator dynamic stiffness method of testing is characterized in that, may further comprise the steps:

(1) by vibration isolator vibrational structure is of coupled connections, arranges acceleration transducer in coupling place;

(2) direct Department of Survey's irrespective of size frequency response function;

(3) directly calculate vibration isolator dynamic stiffness [K according to the system-level frequency response function that records _c].

Described vibrational structure comprises structure A and structure B, and structure A and structure B are of coupled connections by vibration isolator.

Described system-level frequency response function comprises [H _S] _{C (a) c (a)}, [H _S] _{C (b) c (a)}, [H _S] _{C (b) c (b)}[H _S] _{C (a) c (b)}

The described irrespective of size frequency response function [H of Department of Survey _S] _{C (a) c (a)}, [H _S] _{C (b) c (a)}Measuring process is as follows:

At first in structure A and vibration isolator coupling place excitation; Gather again time-domain signal and all acceleration transducer response signals of excitation; Then time-domain signal is carried out Fourier transform and obtain frequency-region signal, adopt H ₁Method of estimation estimated frequency response function:

[H _S] _{C (a) c (a)}=G _AF/ G _FF, G in the formula _AFStructure A and vibration isolator coupling place acceleration responsive { X} _{C (a)}And pumping signal { F} _{C (a)}Cross-power spectrum, G _FFPumping signal { F} _{C (a)}Auto-power spectrum;

[H _S] _{C (b) c (a)}=G _BF/ G _FF, G in the formula _BFStructure B and vibration isolator coupling place acceleration responsive { X} _{C (b)}And pumping signal { F} _{C (a)}Cross-power spectrum, G _FFPumping signal { F} _{C (a)}Auto-power spectrum.

The described irrespective of size frequency response function [H of Department of Survey _S] _{C (b) c (b)}, [H _S] _{C (a) c (b)}Measuring process as follows:

At first in structure B and vibration isolator coupling place excitation; Gather again time-domain signal and all acceleration transducer response signals of excitation; Then adopt H ₁Method of estimation estimated frequency response function:

[H _S] _{C (a) c (b)}=G _AF'/G _FF', G in the formula _AF' be structure A and vibration isolator coupling place acceleration responsive { X} _{C (a)}And pumping signal { F} _{C (b)}Cross-power spectrum, G _FF' be pumping signal { F} _{C (b)}Auto-power spectrum,

[H _S] _{C (b) c (b)}=G _BF'/G _FF', G in the formula _BF' be structure B and vibration isolator coupling place acceleration responsive { X} _{C (b)}And pumping signal { F} _{C (b)}Cross-power spectrum, G _FF' be pumping signal { F} _{C (b)}Auto-power spectrum.

Described vibration isolator dynamic stiffness [K _c] calculation expression be:

$\left[K_c\right]={({\left[H_S\right]}_{c\left(a\right)c\left(a\right)}{\left[H_S\right]}_{c\left(b\right)c\left(a\right)}^{-1}{\left[H_S\right]}_{c\left(b\right)c\left(b\right)}-{\left[H_S\right]}_{c\left(a\right)c\left(b\right)})}^{-1}.$

Compared with prior art, the inventive method can be measured under the situation of detaching equipment not, has good engineering practicability and simplicity, and accurately feasible.

Description of drawings

Fig. 1 is a mechanical system structure figure of the present embodiment.

Fig. 2 is the instrumentation plan of the system-level frequency response function of the present invention.

Fig. 3 is system-level frequency response function [H _S] _{C (a) c (a)}Measured curve, (a), phase-frequency figure wherein; (b), the width of cloth-frequency figure.

Fig. 4 is system-level frequency response function [H _S] _{C (b) c (a)}Measured curve, (a), phase-frequency figure wherein; (b), the width of cloth-frequency figure.

Fig. 5 is system-level frequency response function [H _S] _{C (a) c (b)}Measured curve, (a), phase-frequency figure wherein; (b), the width of cloth-frequency figure.

Fig. 6 is system-level frequency response function [H _S] _{C (b) c (b)}Measured curve, (a), phase-frequency figure wherein; (b), the width of cloth-frequency figure.

Fig. 7 is the dynamic stiffness K that the inventive method obtains _cCurve.

Fig. 8 is the drag angle curve that the inventive method obtains.

Fig. 9 is theoretical dynamic stiffness curve.

Figure 10 is theoretical drag angle curve.

Embodiment

The present invention is described in detail below in conjunction with the drawings and specific embodiments.

Embodiment

Vibration isolator dynamic stiffness method of testing of the present invention may further comprise the steps:

(1) by vibration isolator vibrational structure is of coupled connections, arranges acceleration transducer in coupling place;

As shown in Figure 1, a mechanical system can be expressed as structure A and structure B composition, and structure A and structure B are of coupled connections by vibration isolator C, and the quiet rigidity of vibration isolator C is 4 * 10 ⁵N/m, ratio of damping are 400Ns/m, wherein { X} _{C (x)}The output response of expression minor structure x, x=a, b; { F} _{C (x)}The external drive of expression minor structure x, x=a, b; [K _c] be the vibration isolator dynamic stiffness.

(2) direct Department of Survey's irrespective of size frequency response function;

As shown in Figure 2, system-level frequency response function comprises [H _S] _{C (a) c (a)}, [H _S] _{C (b) c (a)}, [H _S] _{C (b) c (b)}, [H _S] _{C (a) c (b)}

The described irrespective of size frequency response function [H of Department of Survey _S] _{C (a) c (a)}, [H _S] _{C (b) c (a)}May further comprise the steps: at first in structure A and vibration isolator C coupling place excitation; Gather again the time-domain signal { F} of excitation _{C (a)}, structure A and vibration isolator C coupling place acceleration transducer time-domain signal { X} _{C (a)}And the time-domain signal { X} of structure B and vibration isolator C coupling place acceleration transducer _{C (b)}Then time-domain signal is carried out Fourier transform and obtain frequency-region signal, adopt H ₁Method of estimation estimated frequency response function:

[H _S] _{C (a) c (a)}=G _AF/ G _FF, G in the formula _AFStructure A and vibration isolator coupling place acceleration responsive { X} _{C (a)}And pumping signal { F} _{C (a)}Cross-power spectrum, G _FFPumping signal { F} _{C (a)}Auto-power spectrum, [H as shown in Figure 3 _S] _{C (a) c (a)}Measured curve,

[H _S] _{C (b) c (a)}=G _BF/ G _FF, G in the formula _BFStructure B and vibration isolator coupling place acceleration responsive { X} _{C (b)}And pumping signal { F} _{C (a)}Cross-power spectrum, G _FFPumping signal { F} _{C (a)}Auto-power spectrum, [H as shown in Figure 4 _S] _{C (b) c (a)}Measured curve.

The described irrespective of size frequency response function [H of Department of Survey _S] _{C (b) c (b)}, [H _S] _{C (a) c (b)}May further comprise the steps: at first in structure B and vibration isolator coupling place excitation; Gather again the time-domain signal { F} of excitation _{C (b)}, structure A and vibration isolator C coupling place acceleration transducer time-domain signal { X} _{C (a)}And the time-domain signal { X} of structure B and vibration isolator coupling place acceleration transducer _{C (b)}Then adopt H ₁Method of estimation estimated frequency response function:

[H _S] _{C (a) c (b)}=G _AF//G _FF/, G in the formula _AF' be structure A and vibration isolator coupling place acceleration responsive { X} _{C (a}And pumping signal { F} _{C (b)}Cross-power spectrum, G _FF' be pumping signal { F} _{C (b)}Auto-power spectrum, [H as shown in Figure 5 _S] _{C (a) c (b)}Measured curve,

[H _S] _{C (b) c (b)}=G _BF'/G _FF', G in the formula _BF' be structure B and vibration isolator coupling place acceleration responsive { X} _{C (b)}And pumping signal { F} _{C (b)}Cross-power spectrum, G _FF' be pumping signal { F} _{C (b)}Auto-power spectrum, [H as shown in Figure 6 _S] _{C (b) c (b)}Measured curve.

(3) directly calculate vibration isolator dynamic stiffness [K according to the measured system-level frequency response function of step (2) _c]:

$\left[K_c\right]={({\left[H_S\right]}_{c\left(a\right)c\left(a\right)}{\left[H_S\right]}_{c\left(b\right)c\left(a\right)}^{-1}{\left[H_S\right]}_{c\left(b\right)c\left(b\right)}-{\left[H_S\right]}_{c\left(a\right)c\left(b\right)})}^{-1}.$

Experiment institute's dynamic stiffness amplitude of surveying and drag angle curve are distinguished as shown in Figure 7 and Figure 8, and the theoretical dynamic stiffness amplitude of dynamic stiffness and drag angle curve are distinguished as shown in Figure 9 and Figure 10.Comparison diagram 7 and Fig. 9 and Fig. 8 and Figure 10, its result is basically identical, and experimental result shows that the inventive method is accurately feasible.

Claims (6)

1. a vibration isolator dynamic stiffness method of testing is characterized in that, may further comprise the steps:

(1) by vibration isolator vibrational structure is of coupled connections, arranges acceleration transducer in coupling place;

(2) direct Department of Survey's irrespective of size frequency response function;

(3) directly calculate vibration isolator dynamic stiffness [K according to the system-level frequency response function that records _c].

2. a kind of vibration isolator dynamic stiffness method of testing according to claim 1 is characterized in that, described vibrational structure comprises structure A and structure B, and structure A and structure B are of coupled connections by vibration isolator.

3. a kind of vibration isolator dynamic stiffness method of testing according to claim 2 is characterized in that, described system-level frequency response function comprises [H _S] _{C (a) c (a)}, [H _S] _{C (b) c (a)}, [H _S] _{C (b) c (b)}[H _S] _{C (a) c (b)}

4. a kind of vibration isolator dynamic stiffness method of testing according to claim 3 is characterized in that, the described irrespective of size frequency response function [H of Department of Survey _S] _{C (a) c (a)}, [H _S] _{C (b) c (a)}Measuring process is as follows:

At first in structure A and vibration isolator coupling place excitation; Gather again time-domain signal and all acceleration transducer response signals of excitation; Then time-domain signal is carried out Fourier transform and obtains frequency-region signal, adopt H1 method of estimation estimated frequency response function:

[H _S] _{C (a) c (a)}=G _AF/ G _FF, G in the formula _AFStructure A and vibration isolator coupling place acceleration responsive { X} _{C (a)}And pumping signal { F} _{C (a)}Cross-power spectrum, G _FFPumping signal { F} _{C (a)}Auto-power spectrum;

[H _S] _{C (b) c (a)}=G _BF/ G _FF, G in the formula _BFStructure B and vibration isolator coupling place acceleration responsive { X} _{C (b)}And pumping signal { F} _{C (a)}Cross-power spectrum, G _FFPumping signal { F} _{C (a)}Auto-power spectrum.

5. a kind of vibration isolator dynamic stiffness method of testing according to claim 4 is characterized in that, the described irrespective of size frequency response function [H of Department of Survey _S] _{C (b) c (b)}, [H _S] _{C (a) c (b)}Measuring process as follows:

At first in structure B and vibration isolator coupling place excitation; Gather again time-domain signal and all acceleration transducer response signals of excitation; Then adopt H ₁Method of estimation estimated frequency response function:

[H _S] _{C (a) c (b)}=G _AF'/G _FF', G in the formula _AF' be structure A and vibration isolator coupling place acceleration responsive { X} _{C (a)}And pumping signal { F} _{C (b)}Cross-power spectrum, G _FF' be pumping signal { F} _{C (b)}Auto-power spectrum,

[H _S] _{C (b) c (b)}=G _BF'/G _FF', G in the formula _BF' be structure B and vibration isolator coupling place acceleration responsive { X} _{C (b)}And pumping signal { F} _{C (b)}Cross-power spectrum, G _FF' be pumping signal { F} _{C (b)}Auto-power spectrum.

6. a kind of vibration isolator dynamic stiffness method of testing according to claim 5 is characterized in that, described vibration isolator dynamic stiffness [K _c] calculation expression be:

$\left[K_c\right]={({\left[H_S\right]}_{c\left(a\right)c\left(a\right)}{\left[H_S\right]}_{c\left(b\right)c\left(a\right)}^{-1}{\left[H_S\right]}_{c\left(b\right)c\left(b\right)}-{\left[H_S\right]}_{c\left(a\right)c\left(b\right)})}^{-1}.$

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