CN104198145A - Novel method used for measuring frequency response function of extremely fragile component - Google Patents

Abstract

The invention discloses a novel method for measuring frequency response function of an extremely fragile component and belongs to the field of the mechanical vibration. The novel method is mainly characterized by being based on the measured frequency response function HAc(a)c(a) of an auxiliary component and the measured frequency response function HABc(a)c(a) of an assembled system. The novel method comprises the following steps: (1) an acceleration sensor is arranged on an auxiliary component A, the frequency response function HAc(a)c(a) of the auxiliary component A is measured; (2) the extremely fragile component and the auxiliary component are in coupling connection and a sensor is arranged on the assembled system, then the frequency response function HABc(a)c(a) of the assembled system is measured; (3) the frequency response function of the extremely fragile component is directly calculated in accordance with the measured frequency response function of the auxiliary component and the measured frequency response function of the assembled system. The novel method has the advantages as follows: as the novel method is thoroughly based on the measured frequency response functions to predict the frequency response function of the extremely fragile component, the situation that the extremely fragile component is directly subjected to shock excitation or vibration picking is not required; the method has the advantages that the engineering application is simple, and the precision is high.

Description

The new method of the extremely crisp position frequency of components response function of a kind of mensuration

Technical field

The present invention relates to the technical field of mechanical vibration, especially relate to a kind of acquisition methods of extremely crisp position frequency of components response function.

Background technology

Frequency response function is an important indicator of the dynamic mass assessment of engineering goods.In addition, when complicated assembly system is carried out to dynamic mass analysis, generally by the method for theory or experiment test, obtain the frequency response function of all parts, then carry out the dynamic perfromance that Substructure Synthesis obtains total system.Yet, the parts extremely fragile to some, its frequency response function is difficult to directly test by experiment, and the precision of theoretical modeling method is limited by the accuracy of model parameter and boundary condition.The new hot fields that becomes modern mechanical vibration field of obtaining for the frequency response function of vulnerable component extremely.

Summary of the invention

The object of the present invention is to provide that the application of a kind of engineering is convenient, measuring accuracy is high, without directly extremely crisp parts being carried out to method of testing exciting or pick-up, that obtain extremely crisp position frequency of components response function.

The invention provides the method for testing for extremely crisp position frequency of components response function, it is characterized in that: first by additional parts of easily measuring, the frequency response function of assembly system and the frequency response function of optional feature that can be easy to measurement have been utilized, the frequency response function of the extremely crisp parts of prediction, avoided extremely crisp parts to carry out direct exciting and pick-up, comprised the steps:

(1) optional feature is arranged to acceleration transducer, at an exciting that is of coupled connections, measure the acceleration responsive of this point simultaneously, and then obtain the initial point acceleration admittance H of this point _{ac (a) c (a)};

(2) extremely crisp parts and optional feature are of coupled connections, Coupling point is with (1) measurement point, to the system assembling, placement sensor, assembly system measurement point in the step (1) of optional feature and the junction being of coupled connections is carried out to exciting, measure the acceleration responsive of this point simultaneously, measure the frequency response function H of assembly system _{aBc (a) c (a)};

(3), according to the frequency response function of optional feature and the frequency response function of assembly system that record, directly calculate the frequency response function of extremely crisp parts.Computing formula is as follows:

$H_{\mathrm{Bc}\left(b\right)c\left(b\right)}=H_{\mathrm{Ac}\left(a\right)c\left(a\right)}{(H_{\mathrm{Ac}\left(a\right)c\left(a\right)}-H_{\mathrm{ABc}\left(a\right)c\left(a\right)})}^{-1}{H}_{\mathrm{Ac}\left(a\right)c\left(a\right)}-H_{\mathrm{Ac}\left(a\right)c\left(a\right)}-K_c^{-1}$

Wherein, K _cfor A is connected dynamic stiffness with B.

The present invention compared with prior art, has remarkable advantage:

(1) do not need extremely crisp parts exciting or pick-up.

(2) frequency response function of the needed assembly system of formula and the frequency response function of optional feature of the frequency response function of the extremely crisp parts of calculating are obtained by experiment test completely, have avoided FEM (finite element) calculation or the theoretical modeling dependence to model accuracy.

Accompanying drawing explanation

The extremely crisp parts check point schematic diagram that Fig. 1 is to be predicted.

Fig. 2 optional feature check point schematic diagram.

Fig. 3 assembly system check point schematic diagram.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

Embodiment

The method that the present invention measures extremely crisp position frequency of components response function comprises the following steps:

(1) according to boundary geometrical condition and the physical condition of extremely crisp part B (Fig. 1) to be measured, select suitable optional feature A;

(2) optional feature is arranged to acceleration transducer, at an exciting that is of coupled connections, measure the acceleration responsive of this point simultaneously, and then obtain the initial point acceleration admittance H of this point _{ac (a) c (a)}(Fig. 2);

(3) extremely crisp parts and optional feature are of coupled connections, Coupling point is with (1) measurement point, to the system assembling, placement sensor, assembly system measurement point in the step (1) of optional feature and the junction being of coupled connections is carried out to exciting, measure the acceleration responsive of this point simultaneously, measure the frequency response function H of assembly system _{aBc (a) c (a)}(Fig. 3);

(4), according to the frequency response function of optional feature and the frequency response function of assembly system that record, directly calculate the frequency response function of extremely crisp parts.Computing formula is as follows:

$H_{\mathrm{Bc}\left(b\right)c\left(b\right)}=H_{\mathrm{Ac}\left(a\right)c\left(a\right)}{(H_{\mathrm{Ac}\left(a\right)c\left(a\right)}-H_{\mathrm{ABc}\left(a\right)c\left(a\right)})}^{-1}{H}_{\mathrm{Ac}\left(a\right)c\left(a\right)}-H_{\mathrm{Ac}\left(a\right)c\left(a\right)}-K_c^{-1}.$

Subscript in formula " 1 " representing matrix inversion operation.

Above-mentioned (2), (3) measurement of step medium frequency response function can be obtained by " the exciting test " of simple maturation, by " power hammer-accelerometer-multi-channel signal acquiring analytic system " hardware testing system, complete, this system is public physical construction kinetic test analytic system, mainly comprise the power hammer that exciting is used, one group of sensor-accelerometer of vibratory response test use, and multi-channel signal acquiring analytic system, as domestic DASP intelligent signal energy acquisition processing system, 16 or 32 passages, external as LMS, the systems such as BK, multi-channel signal acquiring analyser is mainly by advance signal regulator, (time-frequency Dynamic Signal reads for analog to digital converter and software kit, analyze, show, output, the functions such as printing etc.).

Above-described embodiment is the embodiment that the present invention recommends; but embodiments of the present invention are not restricted to the described embodiments; other any do not deviate from the modification made under core essence of the present invention and principle, substitutes, combination, simplify and all should be equivalent substitute mode, within being included in protection scope of the present invention.

Claims (4)

1. a new method for the extremely crisp position frequency of components response function of mensuration, is characterized in that, comprises the steps:

(1) optional feature is arranged to acceleration transducer, measure its frequency response function H _{ac (a) c (a)};

(2) extremely crisp parts and optional feature are of coupled connections, to the system assembling, placement sensor, the frequency response function H of measurement assembly system _{aBc (a) c (a)};

(3), according to the frequency response function of optional feature and the frequency response function of assembly system that record, directly calculate the frequency response function of extremely crisp parts.Computing formula is as follows:

$H_{\mathrm{Bc}\left(b\right)c\left(b\right)}=H_{\mathrm{Ac}\left(a\right)c\left(a\right)}{(H_{\mathrm{Ac}\left(a\right)c\left(a\right)}-H_{\mathrm{ABc}\left(a\right)c\left(a\right)})}^{-1}{H}_{\mathrm{Ac}\left(a\right)c\left(a\right)}-H_{\mathrm{Ac}\left(a\right)c\left(a\right)}-K_c^{-1}$

Wherein, K _cfor A is connected dynamic stiffness with B.

2. the new method of the extremely crisp position frequency of components response function of a kind of mensuration according to claim 1, is characterized in that, the frequency response function of described measurement comprises: the frequency response function H of optional feature _{ac (a) c (a)}frequency response function H with assembly system _{aBc (a) c (a)}.

3. the new method of the extremely crisp position frequency of components response function of a kind of mensuration according to claim 2, is characterized in that, does not need extremely crisp parts to carry out exciting or pick-up.

4. the new method of the extremely crisp position frequency of components response function of a kind of mensuration according to claim 2, is characterized in that, the computing formula of its frequency response function is

$H_{\mathrm{Bc}\left(b\right)c\left(b\right)}=H_{\mathrm{Ac}\left(a\right)c\left(a\right)}{(H_{\mathrm{Ac}\left(a\right)c\left(a\right)}-H_{\mathrm{ABc}\left(a\right)c\left(a\right)})}^{-1}{H}_{\mathrm{Ac}\left(a\right)c\left(a\right)}-H_{\mathrm{Ac}\left(a\right)c\left(a\right)}-K_c^{-1}.$