JPH0882571A - Vibration measuring apparatus - Google Patents

Abstract

PURPOSE: To enhance estimate accuracy by comparaing a mode shape coefficient extracted by excitation experiment with a finite-element method(FEM) analytical value to perform interpolation correction so as to minimize the difference between them. CONSTITUTION: In an excitation experiment part 1A, an objective structure (e.g. a car engine assembly consisting of an engine block 10a and an oil pan block 10) 10 is excited by an excitation means 6. The data related to the connection point in the imaginary connection region of the region where sensitivity is desired to be analyzed and other internal region of the structure 10 is regarded as a real value with respect to the mode shape coefficient in the vibration characteristics extracted by the analysis due to a modal analyzing means 1. Further, the difference between the data of the internal region excepting the connection point and the mode shape coefficient in the vibration characteristics obtained by an FEM analyzing means 2 is calculated. The mode shape coefficient at a time when the difference becomes min. is set to a correct mode shape coefficient to be inputted to a sensitivity analyzing means 5 by a mode shape coefficient interpolation and correction means 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to the case where the mechanical characteristics such as the shape and structure of a part of a mechanical structure (countermeasure constituent part), mass, rigidity, spring constant, etc. are changed. The present invention relates to a vibration measurement system capable of accurately and efficiently predicting vibration characteristics of a structure (whole structure).

[0002]

2. Description of the Related Art For example, when manufacturing some new mechanical structure, it is of course necessary to consider whether or not the structure is sufficiently safe against a static load, and of course, a dynamic load against a dynamic load. Responsiveness also needs to be carefully examined.

Generally, the mechanical structure as described above (hereinafter,
When a dynamic load is applied to a structure (simply referred to as a structure), mechanical vibration occurs as a dynamic response to the dynamic load. In many cases, such a vibration naturally needs to be suppressed below a certain allowable level. Therefore, when manufacturing a new structure, consider the vibration characteristics of the structure, and if the above vibration exceeds a certain allowable level, consider that part of the structure that causes the problem (countermeasure component part). It is necessary to perform so-called dynamic characteristic development to improve the vibration so that the vibration falls within an allowable level by changing the shape, structure, mass, rigidity, spring constant and the like.

In the development of this dynamic characteristic, when changing the shape, structure, etc. of the above-mentioned countermeasure constituent portion of the structure, what kind of characteristics the vibration of the structure before and after the change has is accurately determined. As a method for investigating the vibration of the structure after the change, for example, a method using modal analysis, a method using FEM (Finite Element Method; finite element method), and those methods have been developed. Sensitivity analysis method and BBA method (Building Block Approac
h; partial structure synthesis method) was adopted.

By the way, in the method using the modal analysis, it is not possible to know how much the dynamic characteristics of the entire structure assembly can be improved by the improvement of the structure without making a trial of the structure improvement plan. Also, it has a drawback that it takes time and cost to manufacture the prototype.

The method using the FEM also has the advantage that it is not necessary to make a new structure that is actually improved, but on the other hand, the characteristics of the joint portion of the structure assembly are not well understood, and therefore, it is suitable. It is difficult to set the characteristics of the joint, the modeling man-hour increases as the target structure becomes large, the calculation time becomes long, and mistakes are likely to occur during modeling and calculation, and it is difficult to find it. There are problems such as

On the other hand, the sensitivity analysis method is suitable for easily evaluating the dynamic characteristics when a mass or a spring is added to a part of countermeasure components, but it is accurate when the structure of the structure itself is changed. Cannot be evaluated.

A dynamic characteristic development method using BBA is as follows.
(a) It is not necessary to actually manufacture the modified countermeasure components as in the case of using modal analysis, (b) The FEM model is created because the already manufactured actual components are used except for the modified countermeasure components. (C) It has an advantage that the calculation time can be shortened.

However, the method using BBA has the following problems.

First, when calculating with BBA, it is necessary to preset the joint characteristic (rigidity) to be constant, but it is difficult to accurately grasp the joint characteristic. Therefore, for example, It is corrected by trial and error, but it is extremely troublesome to do so, and
Even if it does so, it is not always possible to set the correct joint characteristic, and as a result, the prediction error becomes large.

Further, when calculating by BBA, it is necessary to obtain the dynamic characteristic (modal parameter) of the elastic mode and the dynamic characteristic (modal parameter) of the rigid body mode, but it can be obtained by a modal analysis by conducting a vibration experiment. Is the modal parameter of the elastic mode only.Therefore, in the actual calculation, the modal parameter of each component obtained by the vibration experiment should be calculated by ignoring the rigid body mode, or separately for the main members. The test for obtaining the modal parameters of the rigid body mode will be conducted, and the modal parameters of the rigid body mode obtained thereby will be used. However, when the modal parameters of the rigid body mode are ignored in this way, the prediction error becomes very large, and the experiment for obtaining the modal parameters of the rigid body mode is difficult and takes a long time.

Further, particularly when the above-mentioned structure is a power unit for an automobile and the countermeasure component is the cylinder block portion of the engine, and the countermeasure component is the central portion of the assembly, the countermeasure can be taken. When conducting the vibration experiment of the component part except the component part, the remaining part is inevitably divided into many components. Therefore, it is necessary to perform the vibration experiment for each of the same number of components, which is disadvantageous in that it takes time and labor.

Further, for example, when the countermeasure structure portion cannot be easily separated from other portions such as a side sill of a vehicle, it is itself necessary to conduct a vibration test of other component portions excluding the countermeasure structure portion. In some cases, it is difficult to use the vibration measurement system based on BBA.

Furthermore, when a vibration experiment is performed on a large number of components as described above, the experimental errors may be accumulated and eventually the prediction accuracy may be greatly reduced. The deviation rate of the prediction accuracy due to the experimental error is remarkable especially in the case of the mode shape coefficient (described later).

Therefore, as a means for solving such a problem, in the case where the shape of the countermeasure component of the structure is changed, the shape and the like in the vibration test system for obtaining the vibration characteristics of the structure after the change. A modal analysis means for performing a vibration experiment on the entire structure before the change and performing a modal analysis on the actual measurement data obtained as a result of the vibration experiment to calculate the vibration characteristics of the entire structure before the change such as the shape,
FEM analysis means for creating FEM models of the countermeasure component parts before and after changing the shape etc. and calculating the vibration characteristics of both created FEM models, and each countermeasure component part before changing the shape etc. and after changing the mechanical property The change in the vibration characteristic, which is the difference in the vibration characteristics between the FEM models, is calculated, and the change in the vibration characteristic is added to the vibration characteristic of the structure before the change in the shape calculated by the FEM analysis means to change the shape and the like. There has been proposed a structure provided with a vibration characteristic calculation means for calculating the vibration characteristic of the structure later (see, for example, Japanese Patent Application Laid-Open No. 2-120636).

First, the dynamic characteristics of the entire structure before changing the shape etc. obtained by the modal analysis means are, for example, modal parameters, that is, φo (mode shape coefficient), mo (modal mass coefficient) and ko (modal stiffness coefficient). is there.

Next, the dynamic characteristics of the countermeasure component before and after the mechanical characteristic change obtained by the FEM analysis means are, for example, [M] (physical mass matrix) and [K] in the countermeasure component before change. (Physical stiffness matrix), and in the countermeasure component after the mechanical property change, it is [M '] (physical mass matrix) and [K'] (physical stiffness matrix).

The above-mentioned vibration characteristic calculation means has been newly developed by the present inventors, and is an E-BBA (Extracting & Building).
BLOCK APPROACH) is a means for executing calculation based on a calculation theory, and the calculation theory E-BBA is a development of the partial structure synthesis method BBA, and has, for example, the following formula as a basic formula. Is.

[0019]

[Equation 1]

Based on the basic equation of E-BBA, the dynamic characteristics of the structure after changing the shape, for example, modal parameters, ie, φ '(mode shape coefficient), m' (modal mass coefficient) and k '(modal modal). Stiffness coefficient) is obtained, and vibration evaluation can be performed by obtaining the natural frequency and transfer function from them.

The method using this E-BBA is the same as the above BB.
Similar to the method using A, at least the countermeasure components after changing the shape etc. are subjected to FEM analysis by the FEM analysis means, so that it is not necessary to actually create the countermeasure components after changing the shape etc. Does not need to make a large number of FEM modeling for each component because it is performed only for the countermeasure components before and after changing the shape, etc. Therefore, the original advantage of BBA can be taken over as it is.

Further, the vibration test may be carried out only once for the entire structure before changing the shape and the like of the countermeasure component, and as described above, this applies to the entire structure before changing the shape and the like excluding the countermeasure component. In the method using BBA described above, in which a predetermined number of components are divided and a vibration experiment is performed on each component, when the countermeasure constituent part is located in the center, for example, the remaining part is necessarily equivalent. Since it is often divided into a large number of components, and as a result, it is often the case that a vibration test must be performed a large number of times, this is an extremely significant advantage in the sense that the number of test steps is reduced. Further, since the number of test steps is small as described above, it is possible to reduce time and cost and eliminate errors accumulated.

Further, since the vibration test is performed at least once for the entire structure before changing the shape and the like, for example, in the case where the structural part is the body of the automobile, and the countermeasure constituent part thereof. The present method can be easily applied to the case where it cannot be easily separated as in the case of the side sill portion.
This is a great advantage over the method using BA.

Further, in the method using BBA, if the rigid body mode is ignored, a large error occurs. Therefore, it cannot be ignored. However, in the method using E-BBA, the error is small even if the rigid body mode is ignored. Can often ignore rigid body modes. In particular, the difference in mass before and after changing the shape etc.
If it is less than%, the error is 0.7% even if the rigid body mode is ignored.
It is 0.8% or less (confirmed by theoretical calculation), and there is almost no problem.

Further, in the above-mentioned method using E-BBA, it is possible to solve the problem that it is difficult to accurately grasp the characteristic of the joint portion, which is remarkable in the method using BBA. That is, in the method using E-BBA, since the dynamic characteristics of the entire structure are first obtained, the characteristics of each joint are eventually included in the dynamic characteristics of the entire structure. When the shape of the countermeasure component is changed, it is rare that the joining portion is changed. Therefore, assuming that the joining portion is not changed, the countermeasure component is not changed. , So that the FEM model also does not include a joint,
Then, the physical stiffness matrix before and after the change of the model can also be made to not include the characteristic of the joint portion, and thus E-BB
According to the vibration characteristic calculation system using A, the dynamic characteristics of the changed assembly can be predicted without grasping the characteristics of the joint portion.

Of course, when the joint portion changes, an FEM model is made in the state that the joint portion is included, and between the physical stiffness matrices [K] and [K '] which are the FEM analysis values before and after the above-mentioned shape change and the like. By calculating the change [ΔK] by including both the change in the internal rigidity of the countermeasure component to be changed and the change in the joint rigidity, it is possible to obtain a result in which the change in the joint is properly considered. it can.

[0027]

As described above, the above E
-The vibration measurement system using the BBA method requires the minimum number of man-hours to predict the vibration characteristics after changing the shape and structure, and is more accurate than the vibration measurement system using the sensitivity analysis method and the BBA method. Although there is a feature, on the other hand, if there is an experimental error in the vibration experiment itself, accurate prediction may not always be possible. This point is exactly the same as the vibration measuring system adopting the conventional sensitivity analysis method and the vibration measuring system using the BBA method (although the accumulated error is small, of course).

Experimental errors that commonly occur in both the sensitivity analysis and the BBA and E-BBA systems include, for example, an experimental error for the natural frequency and an experimental error for the mode shape coefficient φo (note that the results of the vibration experiment are shown). Experimental error is also included in modal mass, but the modal mass is in units (=
By setting to 1), the error can be included in the mode shape coefficient experimental error).

Of these, first of all, the natural frequency is to measure the cycle of vibration using a vibration measuring device such as an acceleration pick-up, and can be measured with sufficient accuracy in the current vibration measuring device. Is. Therefore, it can be said that there is no problem as long as accurate measurement is performed.

However, with respect to the mode shape coefficient φo, a large prediction error may occur due to the proximity error. The state is shown in FIG. 11, FIG. 12 and FIG.
3 shows. 11 and 12 show an engine block side 10 of an automobile power unit 10 as shown in FIG. 5, for example.
a and the transmission side block 10d are integrated stiffeners 10f as shown in FIG. 14 and FIG.
(Before change), 10f '(after change), the structure which was reinforced and connected was modeled as beam members 10, 10' with both ends fixed, and the mode shape coefficient φo of the bending mode was measured. If the deviation due to the experimental error is represented as a deviation rate, for example, as shown in FIG. 9, a prediction error ΔA of 30% occurs at a deviation rate of 20% at 220 Hz with respect to the correct value 227 Hz (in the case of the primary mode). so).

As a result, there is a problem that the mechanical characteristics of appropriate countermeasure components cannot be changed.

The present invention has been made to solve the above problems, and it seems that the mode shape coefficient extracted by the vibration experiment as described above is theoretically correct by comparison with the FEM analysis value. It is an object of the present invention to provide a vibration measurement system in which the prediction accuracy is improved as much as possible by performing interpolation correction so that the difference from the FEM analysis value is minimized by the method.

[0033]

Each of the first to fourth inventions of the present application comprises the following problem solving means in order to solve the above problems and effectively achieve the object. Has been done.

That is, first, in the first invention of the present application, in the case of changing the mechanical characteristics of the countermeasure constituent portion of the structure,
A vibration measurement system that obtains the vibration characteristics of the entire structure after changing the mechanical characteristics by a sensitivity analysis method, and performs a vibration experiment on the entire structure including the above-mentioned countermeasure components, and obtains the results of the vibration experiment. Modal analysis means for performing modal analysis on the measured data of the entire structure and calculating the respective vibration characteristics of the entire structure and the area to be subjected to the sensitivity analysis of the countermeasure component, and the countermeasure component of the structure An FEM model of a region to be subjected to sensitivity analysis is created, and the created FEM model is subjected to FEM analysis to calculate the vibration characteristics thereof, and the vibration characteristics of the FEM model calculated by the FEM analysis means and the above By combining the vibration characteristics of the entire structure and the sensitivity analysis area calculated by the modal analysis means, the structure after the mechanical characteristics of the countermeasure component is changed. In vibration measurement system comprising a sensitivity analyzing means for calculating predicted vibration characteristics of the entire object,
Regarding the mode shape coefficient of the vibration characteristics obtained by the modal analysis by the modal analysis means, the data regarding the connection point in the virtual connection region between the region to be subjected to the sensitivity analysis of the structure and the other internal region is regarded as a true value. On the other hand, for the data of the internal region excluding the connection point, a difference from the mode shape coefficient in the vibration characteristics obtained by the FEM analysis means is obtained, and the mode shape coefficient when the difference becomes the minimum is determined as the correct mode shape. A mode shape coefficient interpolating / correcting means for inputting to the sensitivity analyzing means as a coefficient is provided.

Next, the second invention of the present application is a vibration measuring system for obtaining the vibration characteristic of the whole structure after the mechanical characteristic is changed by the BBA method when the mechanical characteristic of the countermeasure component of the structure is changed. In addition, a vibration test was performed on each component of the structure before the mechanical characteristics were changed, except for the above-mentioned countermeasure components, and modal analysis was applied to the measured data of each component obtained as a result of the vibration test. A modal analysis means for calculating the vibration characteristics of each component of the structure before the change of the mechanical characteristics except the above-mentioned countermeasure constituent portion, and F of the above-mentioned countermeasure constituent portion after the mechanical characteristic change.
EM model is created and FE is added to the created FEM model.
FEM analysis means for performing M analysis to calculate the vibration characteristics thereof, and vibration characteristics of the FEM model of the countermeasure component after the mechanical characteristics change calculated by the FEM analysis means and the machine calculated by the modal analysis means. BBA vibration characteristic calculation means for calculating and predicting the vibration characteristics of the entire structure after the mechanical characteristics are changed by combining with the vibration characteristics of the respective components of the structure before the change of the mechanical characteristics, except for the countermeasure constituent parts. In the vibration measurement system, regarding the mode shape coefficient in the vibration characteristics obtained by the modal analysis by the modal analysis means, data regarding the connection point in the virtual connection region between the countermeasure component portion and the non-countermeasure component portion of the structure is On the other hand, the data in the internal area of the non-countermeasure constituent part side except the connection point is regarded as the true value.
The difference between the vibration characteristic obtained by the EM analysis means and the mode shape coefficient is obtained, and the mode shape coefficient when the difference is minimized is input to the BBA vibration characteristic calculation means as the correct mode shape coefficient. Coefficient interpolation correction means is provided.

Further, the third invention of the present application is a vibration measuring system for obtaining the vibration characteristic of the whole structure after the mechanical characteristic is changed by the E-BBA method when the mechanical characteristic of the countermeasure component of the structure is changed. In addition, a vibration test is performed on the entire structure before the mechanical characteristics are changed, and the measured data obtained as a result of the vibration test is subjected to a modal analysis to obtain the vibration of the entire structure before the mechanical characteristics are changed. Modal analysis means for calculating the characteristics, and FEM models of the above-mentioned countermeasure components before and after the change of the mechanical characteristics are created, and both the created FEs are created.
FEM analysis means for performing each FEM analysis on the M model to calculate each vibration characteristic, and FEM of the countermeasure component portion before the mechanical characteristic change calculated by the FEM analysis means.
After changing the vibration characteristic of the model and the mechanical characteristic after changing the mechanical characteristic, the change in the vibration characteristic, which is the difference between the vibration characteristic of the FEM model of the constituent part, is calculated, and the change in the vibration characteristic is calculated by the modal analysis means. In the vibration measurement system including E-BBA vibration characteristic calculation means for calculating and predicting the vibration characteristic of the entire structure after the mechanical characteristic change by adding to the vibration characteristic of the entire structure before change, the modal analysis is performed. Regarding the mode shape coefficient of the vibration characteristics obtained by the modal analysis by means, the data regarding the connection point in the virtual connection region between the countermeasure component portion and the non-countermeasure component portion of the structure is regarded as the true value, The data in the internal area of the non-countermeasure component side excluding the points is the above FEM
The difference between the vibration characteristic obtained by the analyzing means and the mode shape coefficient is obtained, and the mode shape coefficient when the difference is minimized is used as the correct mode shape coefficient.
A mode shape coefficient interpolation correcting means for inputting to the BBA vibration characteristic calculating means is provided.

The fourth invention of the present application is based on the above-mentioned second and third inventions.
In the case of using both the BBA and E-BBA systems of the present invention, the BBA and E-BBA vibration characteristic calculation means is provided with a sensitivity analysis means as a post-processing means, so that the prediction accuracy can be further improved. Has become.

[0038]

As a result of the above construction, the vibration measuring systems of the first, second, third, and fourth inventions of the present application have the following operations corresponding to the respective constructions.

That is, first, in the first invention of the present application, as described above, a vibration test is performed on the entire structure including a countermeasure component portion for changing mechanical characteristics by adding a mass or a spring, The entire structure obtained by the vibration experiment and the entire structure of the structure by applying modal analysis (for example, frequency analysis, curve fit) by modal analysis means to each measured data of the sensitivity analysis area of the countermeasure component part Each vibration characteristic of the area for sensitivity analysis, that is, modal parameters (mode shape coefficient, modal mass coefficient m
o, modal stiffness coefficient Ko, etc.).

Next, an FEM model of the region for which the sensitivity of the countermeasure component is desired to be analyzed is created, and the created FEM model is subjected to FEM analysis by FEM analysis means, and its vibration characteristics (physical mass matrix, physical stiffness matrix). Is calculated. Further, by the FEM analysis by the FEM analysis means and the mode shape coefficient (φo) of the vibration characteristics obtained by performing modal analysis by the modal analysis means on the measured data by the mode shape coefficient interpolation correction means. The difference with the obtained vibration characteristic is calculated, and the mode shape coefficient when the difference is the minimum is corrected by interpolation and input to the sensitivity analysis means.

In that case, the actual measurement data of the connection point in the virtual connection area between the area for which the sensitivity analysis of the mechanical characteristic change section is desired and the non-change section side internal area is treated as a true value, and the internal area excluding the virtual connection area is treated. Do the above only for the data of.

As a result, the analysis error based on the experimental error in the modal analysis of the modal analysis means is minimized.

Next, in the second invention of the present application, as described above, the part except for the countermeasure constituent part of the whole structure before changing the mechanical characteristics such as shape and structure is divided into a plurality of components, A vibration experiment is performed for each component, and modal analysis (for example, frequency analysis, curve fit) by modal analysis means is performed on the actual measurement data of each component obtained in the vibration experiment before changing the mechanical characteristics. The vibration characteristics of each component of the structure, that is, the modal parameters (mode shape coefficient φo, modal mass coefficient mo, modal stiffness coefficient Ko, etc.) are obtained. Next, an FEM model of the countermeasure component part after the mechanical characteristic change is created, and the created FEM model after the mechanical property change is subjected to FEM analysis by the FEM analysis means, and its vibration characteristics (physical mass matrix, Calculate the physical stiffness matrix).

Further, the mode shape coefficient (φo) of the vibration characteristics obtained by performing modal analysis by the modal analysis means on the measured data by the mode shape coefficient interpolation correction means and the FEM analysis means. The difference from the vibration characteristics obtained by FEM analysis is calculated, and the partial shape synthesis method is adopted after the mode shape coefficient when the difference is the minimum is corrected by interpolation and correct.
Input to BA vibration characteristic calculation means.

In that case, the actual measurement data at the connection point of the virtual connection area between the mechanical characteristic changing portion and the mechanical characteristic non-changing portion is treated as a true value, and the data in the non-change portion side internal area excluding the connecting point is treated. Only like this.

As a result, the analysis error based on the experimental error in the modal analysis of the modal analysis means is minimized.

Further, in the third invention of the present application, as described above, the vibration test is conducted on the entire structure before the mechanical characteristics are changed, and the modal analysis means is applied to the measured data obtained by the vibration test. The vibration characteristics of the entire structure before changing the mechanical characteristics, i.e., modal parameters
(For example, mode shape coefficient φo, modal mass coefficient mo,
Modal stiffness coefficient Ko etc.) is obtained. Next, an FEM model of the countermeasure component part before and after the mechanical characteristic change is created, and the created FEM models before and after the mechanical property change are respectively FE by the FEM analysis means.
M analysis is performed to calculate each vibration characteristic.

Further, the mode shape coefficient (φo) of the vibration characteristics obtained by performing modal analysis by the modal analysis means on the measured data by the mode shape coefficient interpolation correction means and F by the FEM analysis means.
E-BBA vibration characteristics obtained by calculating the difference from the vibration characteristics obtained by EM analysis, interpolating and correcting the mode shape coefficient when the difference is minimum, and then improving and developing the above partial structure synthesis method. Input to calculation means.

In this case, the actual measurement data at the connection point of the virtual connection area between the mechanical characteristic change section and the mechanical characteristic non-change section is treated as a true value, and the data in the non-change section side internal area excluding the same connection point is treated. Only like this.

As a result, the analysis error based on the experimental error in the modal analysis of the modal analysis means is reduced as much as possible.

After that, the vibration characteristics of the FEM model of the countermeasure component before the mechanical characteristic change analyzed by the FEM analysis means and the F of the countermeasure component after the mechanical characteristic change are obtained.
A vibration characteristic change amount, which is a difference from the vibration characteristic of the EM model, is calculated, and the vibration characteristic change amount is calculated by the E-BBA vibration characteristic calculation means by the modal analysis means.
Further, the mode shape coefficient is interpolated and corrected by the mode shape coefficient interpolation correcting means and added to the vibration of the entire structure before the mechanical characteristic is changed to finally obtain the vibration characteristic of the entire structure after the mechanical characteristic is changed. Calculate As a result, similar to the case of the second aspect of the invention, reliable smoothing is performed and the experimental error of modal analysis is eliminated.

Further, in the vibration measuring systems of the third and fourth aspects of the present invention, since the sensitivity analysis is further performed as a post-process after each of the BBA and E-BBA measuring systems, the measurement accuracy is further improved.

[0053]

Therefore, according to the vibration measuring system of the present invention, the accuracy of predicting the vibration characteristics of the entire structure can be greatly improved in the end, and appropriate mechanical characteristics changing measures can be taken.

[0054]

【Example】

(Embodiment 1) FIGS. 1 and 2 show a vibration measuring system according to a first embodiment of the present invention which employs a sensitivity analysis method.

First, FIG. 1 shows the basic configuration of the entire system, which is roughly classified into a vibration experiment section 1A,
The signal processing / calculation unit 1B, the modal analysis unit 1C, the FEM analysis unit 2, the mode shape coefficient interpolation correction unit 3, and the sensitivity analysis unit 5 are provided.

First, the vibration test section 1A vibrates a target structure (for example, an automobile engine assembly including an engine block 10a and an oil pan block 10b as shown in the structure of FIG. 2). Excitation means 6
And first and second vibration detection means 36A, 36B such as an acceleration pickup for detecting the vibration force and vibration acceleration of the structure 10 vibrated by the vibration means 6. . In addition, the signal processing calculation unit 1B includes a data collection unit 11 that collects the respective vibration detection data from the first and second vibration detection units 36A and 36B, and vibration data (added by the data collection unit 11). Frequency analysis means (FFT) 12 for performing frequency analysis by applying a fast Fourier transform to vibration force and vibration acceleration, and the frequency analysis means 12
And a transfer function calculating means 13 for calculating the transfer function (frequency-acceleration curve) of the vibration data based on the frequency analysis.

Further, the mode analysis unit 1C performs a curve fitting process (modal analysis) on the transfer function calculated by the transfer function calculation unit 13 of the signal processing calculation unit 1B to obtain vibration characteristics (modal parameter φo, mo, k
It is configured to have a curve fit processing means 14 for calculating o).

Next, the FEM analysis means 2 performs the FE on the countermeasure constituent portion (for example, the oil pan block portion of the engine) 10b for which the sensitivity analysis of the structure 10 is desired.
Create an M model (FEM model of area B in FIG. 2) and
The FEM analysis values (physical mass matrix M, physical inertia matrix K) of the FEM model are respectively calculated by M analysis, and the FEM model creation program and the FEM analysis program corresponding to them are provided.

Further, the mode shape coefficient interpolation correcting unit 3
Is a countermeasure component unit 1 for which the sensitivity analysis of the structure 10 is desired.
First and second data memories for inputting and storing the mode shape coefficients φA + B, φB for the connection state of at least two areas of the area B which is 0b and the area (internal area) A which is the non-countermeasure constituent part 10a. 31,32 and the above F
The EM analysis means 2 analyzes the eigenvalue of the countermeasure component 10b before the mechanical characteristics are oscillated, the eigenvalue analysis program, and the eigenvalues ([M], [K]) analyzed by the eigenvalue analysis program. The mode shape coefficient φ of the region B alone where the sensitivity analysis is to be performed in a state where the coupling region of the structure 10 (the virtual coupling region A + B of FIG. 2) is not fixed using the memory value φA + B of the first data memory 31.
First mode shape coefficient calculation means 33 for calculating as
And second mode shape coefficient calculation means 34 for calculating the mode shape coefficient φbs of the area B (measure change section 10b) where sensitivity analysis is to be performed with the virtual coupling area (A + B in FIG. 2) of the structure 10 fixed. , And a mode shape coefficient interpolation correcting means 35.

Further, the sensitivity analysis means 5 carries out a sensitivity analysis based on the transfer function calculated by the transfer function calculation means 13 to analyze and predict the vibration characteristic after the mass addition and the spring addition.

Next, a vibration measuring method (dynamic characteristic developing method) by the vibration measuring system of the embodiment of the present invention configured as described above will be explained. In the method described below, for example, a prototype structure 10 such as an actual automobile engine assembly as shown in FIG. 1 exists, and the countermeasure component portion 10b such as an oil pan block portion, which is a component thereof, has a mass, for example. Is added or a spring is added to change the mechanical characteristics, so that the subsequent vibration of the structure 10 such as the engine assembly is measured and evaluated as accurately as possible.

First, a predetermined load is applied by the vibrating means 6 to the entire structure 10 before adding mass or the like to the countermeasure component 10b, and the vibration of the structure 10 caused by the load (exciting force and countermeasure). (Vibration of the constituent portion 10b) is detected by the first and second vibration detecting means 36A, 3 such as an acceleration pickup.
6B, respectively. Such vibration detection is performed at, for example, several points of the two component parts 10a and 10b. Then, the exciting force (F) given by the vibrating means 6 and detected by the first vibration detecting means 36A and the vibration acceleration (α ₁ ) detected by the second vibration detecting means 36B,
(α ₂ ) ··· are temporarily stored by the above data recording program. After that, the data (F), (α ₁ , α ₂ ···) is FFed.
Frequency analysis (that is, Fourier transform) is performed by the Fourier transform program of the frequency analysis unit 12 having a T (Fast Fourier Transform) function, and the transfer function calculation unit 13 is based on the frequency analysis (10a +).
10b) and each transfer function of only the countermeasure component 10b, for example, a frequency-acceleration (α / F) curve is obtained. Then, a curve fitting program of the curve fitting processing means 14 of the mode analyzing unit 1C performs a curve fitting on a specific peak of the transfer function to obtain a modal parameter which is a dynamic characteristic, that is, a mode shape coefficient (φA), (φB). , Modal mass (mo) and modal stiffness (ko) coefficients. The mode shape coefficients φA and φB among them are determined by the first and second data memory 3
Input once to 1,32 and store in memory.

On the other hand, the FEM of the FEM analysis means 2 is also used.
Area B where you want to analyze the sensitivity of the component 10b after the countermeasure is changed by the model creation program.
Of the physical mass matrix [M] and the physical stiffness matrix [K], which are the dynamic characteristics of the FEM model after the above measures are changed, by performing the FEM analysis by the FEM analysis program of the FEM analysis means 2 respectively. Ask.

Next, the first and second mode shape coefficient calculation means 33, 3 of the mode shape coefficient interpolation correcting section 3 are described.
4, the virtual joint area of the structure 10 shown in FIG.
The mode shape coefficients φas and φbs are calculated respectively when (A + B) is not fixed and when it is fixed. Then, the calculated value φ
Using as, φbs, the mode shape coefficient φ when the difference from the FEM analysis value becomes the minimum is corrected by the mode shape coefficient interpolation correcting means 35 as a correction value, and set as a correct mode shape coefficient.

After that, the mode shape coefficient obtained by the curve fitting processing means 14 is removed,
Modal parameters such as modal mass mo and modal stiffness Ko, and the above mode shape coefficient interpolation correcting means 3
FE of the sensitivity analysis area B of the countermeasure change section corrected by 5.
Dynamic characteristics of M model (physical mass matrix [M], physical stiffness matrix
And [K]) into the sensitivity analysis calculation means 5.

After that, the sensitivity analysis program of the sensitivity analysis calculation means 5 executes the sensitivity analysis based on the basic equation of the sensitivity analysis. Then, by doing so, an accurate modal parameter that is the dynamic characteristic of the entire structure 10 after the countermeasure change is obtained.

Therefore, it becomes possible to appropriately evaluate the vibration of the entire structure 10 after the countermeasure is changed.

As described above, according to the vibration measuring system of the present embodiment, it is possible to surely smooth the proximity error of the mode shape coefficient in the experiment with respect to the structure of which the shape etc. are changed, and the prediction accuracy is greatly improved. It can be done.

(Second Embodiment) FIGS. 3 and 4 show a vibration measuring system according to a second embodiment of the present invention which employs the BBA method.

First, FIG. 3 shows the basic configuration of the entire system, which is roughly classified into the vibration test section 1A,
Signal processing calculation unit 1B, modal analysis unit 1C, first and second FEM analysis units 2A and 2B, mode shape coefficient interpolation correction unit 3, BBA vibration characteristic calculation unit 4A, and sensitivity as a post-processing system. The analyzing means 5 is provided.

Then, first, the vibration test section 1A uses the target structure (for example, the engine block 1 as shown in the drawing).
0a and a power unit assembly 10 for an automobile including an additional block portion 10c for mounting a transmission, and a vibrating means 6 for vibrating the vibrating means 6 and a vibrating force and a vibration acceleration of the structure 10 vibrated by the vibrating means 6. First and second vibration detecting means 36 such as an acceleration pickup for detecting
It is composed of A and 36B. Further, the signal processing calculation section 1B includes the first and second vibration detecting means 36A, 36B.
Data collection means 11 for collecting vibration detection data from the
A frequency analysis means (FFT) 12 for performing a fast Fourier transform on the vibration data collected by the data collection means 11 to perform a frequency analysis; and transmission of the vibration data based on the vibration data frequency-analyzed by the frequency analysis means 12. Transfer function calculating means 13 for calculating a function (frequency-accelerator curve)
It consists of and. In addition, the mode analysis unit 1C performs modal analysis on each of the transfer functions to perform vibration characteristics.
The curve fitting processing means 14 for calculating (modal parameters φo, mo, ko) is provided.

Next, the above-mentioned first and second FEM analysis means 2
A and 2B are the coupling area (A + B in FIG. 4) and the FEM model (additional model, that is, FIG. Four
B only), and further by FEM analysis, the FEM analysis value (physical mass matrix) of each FEM model.
[M], [M '], physical inertia matrix [K], [K']) are calculated respectively.
It is formed by having an M model creation program and an FEM analysis program.

Further, the mode shape coefficient interpolation correcting unit 3
Are the mode shape coefficients φA and φB before and after the change of the coupling state of at least two components (divisional blocks) of the countermeasure changing portion (additional portion) 10c and the non-changing portion (main body portion) 10a of the structure 10, respectively. First and second data memories 31 and 32 which are input and stored, and an eigenvalue analysis program for analyzing the eigenvalues of the countermeasure component 10a before the change which is excited by the first FEM analysis means 2A, and the eigenvalues Eigenvalue analyzed by the analysis program
([M], [K] and the memory value φ of the first data memory 31
Using A and A, the binding region of the structure 10 (A + B in FIG. 4)
The first mode shape coefficient calculation means 33 for calculating the mode shape coefficient φas of the constituent component alone and the coupling area (A + B in FIG. 4) of the structure 10 before the mechanical characteristic change are fixed. A second mode shape coefficient calculating means 34 for calculating the mode shape coefficient φbs of the countermeasure changing unit 10b in the state and a mode shape coefficient interpolation correcting means 35 are provided.

Further, the BBA vibration characteristic calculation means 4A
Is the modal mass mo and modal stiffness ko among the modal parameters calculated by the curve fit processing means 14 of the modal analysis means 1, the mode shape coefficient φo modified by the mode shape coefficient interpolation modifying means 35, and the 2 FEM analysis means 2B FEM
A BBA analysis program for inputting the analysis values [M '] and [K'] to obtain the dynamic characteristics of the entire structure 10 after the mechanical characteristics have been changed by the BBA calculation theory.

In the above structure, the structure 10
For the natural vibration mode (especially in the internal region excluding the connection point), the piecewise structure synthesis method (so-called CM
S) is used.

Next, a vibration measuring method (dynamic characteristic developing method) by the vibration measuring system of the embodiment of the present invention configured as described above will be explained. In the method described below, a structure 10 such as a prototype engine assembly for an actual automobile exists as shown in FIG. 3, for example, and a transmission mounting additional block 10c is added to an engine block portion 10a, which is a main component thereof. When the mechanical characteristics are changed by adding, the vibration of the structure 10 such as the engine block assembly after the characteristic change is measured and evaluated as accurately as possible.

First, a predetermined load is applied by the vibrating means 6 to the entire structure 10 before changing the mechanical characteristics with respect to the countermeasure components, and the exciting force and overall vibration of the structure 10 caused by the load are applied. It is detected by the first and second vibration detecting means 36A, 36B such as an acceleration pickup. Such vibration detection is performed by the two component parts 10
For example, several points a, 10c are used. Then, the exciting force (F) applied by the exciting means 6 detected by the first vibration detecting means 36A and the vibration accelerations (α ₁ ) and (α ₂ detected by the second vibration detecting means 36B). ) And ... are temporarily stored by the data recording program of the data collecting means 11. Then, the data (F), (α ₁ , α ₂ ...)
Frequency analysis (that is, Fourier transform) is performed by the Fourier transform program of the frequency transform means 12 having a (Fast Fourier Transform) function, and based on the frequency analysis (ie, Fourier transform), the entire structure (10a
+ 10c) and each transfer function of only the countermeasure component 10c, for example, a frequency-acceleration (α / F) curve. Next, the curve fit processing means 1 in the mode analysis unit 1C
By performing curve fitting processing on a specific peak of the transfer function by the curve fitting processing program of No. 4, modal parameters that are dynamic characteristics, that is, mode shapes (φA), (φB), modal mass (mo) and modal stiffness. (ko) Calculate the coefficient. The mode shape coefficients .phi.A and .phi.B among them are once input and stored in the first and second data memories 31 and 32.

On the other hand, by the FEM model creating programs of the first and second FEM analyzing means 2A and 2B,
Regarding the above countermeasure components, FEM models of both the joint area (A + B in FIG. 4) of the countermeasure changing unit 10c and the countermeasure constituent portion 10c after countermeasure change (additional model shown in B of FIG. 4) are created. F by each FEM analysis program
EM analysis is performed to obtain the physical mass matrix [M] and the physical stiffness matrix [K], which are the dynamic characteristics of the FEM model (additional model) in the above-mentioned coupling region, and the dynamic characteristics of the FEM model of the countermeasure component unit 10c after the countermeasure is changed. A physical mass matrix [M '] and a physical stiffness matrix [K'] are obtained.

Next, the first and second mode shape coefficient calculating means 33, 3 of the mode shape coefficient interpolation correcting section 3 are described.
4 by the binding region (A +) of the structure 10 shown in FIG.
The mode shape coefficients φas and φbs when B) is not fixed and when it is fixed are respectively calculated. Then, the calculated value φas,
By using φbs, the mode shape coefficient φo when the difference from the FEM analysis value becomes the minimum is corrected as a correction value by the mode shape coefficient interpolation correcting means 35 and set as a correct mode shape coefficient.

Then, after that, the mode shape coefficient φ
modal parameters such as modal mass mo, modal stiffness Ko, etc. and FEM analysis values of the second FEM analysis means 2B [M '], [K'] excluding o and the mode shape coefficient obtained by the curve fitting process. ] And B
The BA vibration characteristic calculation means 4A is supplied.

Then, the dynamic characteristic calculation program of the BBA calculating means 4 calculates the dynamic characteristic according to the basic equation, and the structure after the countermeasure is changed.
(A modal parameter, which is a dynamic characteristic of the entire engine assembly 10 to which the transmission mounting additional block 10c is mounted, is obtained.

Therefore, it becomes possible to properly evaluate the vibration of the entire structure 10 after the countermeasure is changed.

As described above, according to the vibration measuring system of the present embodiment, it is possible to surely smooth the proximity error of the mode shape coefficient by the experiment with respect to the structure having a changed shape, and the prediction accuracy is greatly improved. Can be made.

(Embodiment 3) FIGS. 5 to 10 show a vibration measuring system according to a third embodiment of the present invention which employs the E-BBA method.

First, FIG. 5 shows the basic configuration of the entire system, which is roughly classified into the vibration test section 1A,
The signal processing calculation unit 1B, the modal analysis unit 1C, the FEM analysis unit 2, the mode shape coefficient interpolation correction unit 3, and E-
It comprises BBA vibration characteristic calculation means 4 and sensitivity analysis means 5 as a post-processing system.

Then, first, the vibration test unit 1A uses the target structure (for example, the engine block 1 as shown in the drawing).
0a and a transmission block 10d for a vehicle power unit assembly) 10 for vibrating the vibrating means 6, and the structure 10 vibrated by the vibrating means 6
It is composed of first and second vibration detecting means 36B and 36C such as an acceleration pickup for detecting the vibration. Further, the signal processing calculation unit 1B performs a Fourier transform on the vibration data collected by the data collection means 11 that collects the vibration detection data from the first and second vibration detection means 36B and 36C, and the data collection means 11. Frequency analysis means (FFT) 12 for applying and performing frequency analysis, and the frequency analysis means 12
And a transfer function calculating means 13 for calculating the transfer function based on the vibration data subjected to frequency analysis. The mode analysis unit 1C also performs a modal analysis on each of the transfer functions to calculate a vibration characteristic (modal parameters φo, mo, ko).
4 is configured.

Next, the above-mentioned first and second FEM analysis means 2
A and 2B respectively create a FEM model (Fig. 6) before the countermeasure is changed and an FEM model after the countermeasure are changed (Fig. 7) for the countermeasure constituent portion 10a of the structure 10 (for example, the engine block portion of the power unit). , Further FEM
The FEM analysis values (physical mass matrix, physical inertia matrix) of each of these models are calculated by analysis, and the FEM model creation program and the FEM analysis program are formed correspondingly to them. .

Further, the mode shape coefficient interpolation correcting unit 3
Is a countermeasure changing portion 10a and a non-changing portion 10d of the structure 10.
Mode shape coefficient φ before and after the change of the connection state of at least two components (division block) with and
Eigenvalue analysis for analyzing the eigenvalues of the first and second data memories 31, 32 for inputting and storing A and φB, respectively, and the pre-change countermeasure component 10a vibrated by the first FEM analysis means 2A. The structure 1 using the program, the eigenvalues ([M], [K] analyzed by the eigenvalue analysis program, and the memory value φA of the first data memory 31).
Countermeasures in the state where the coupling region 10e of 0 is not fixed The first mode shape coefficient computing means 33 for computing the mode shape factor φas of the constituent component alone and the coupling region 10e of the structure 10 before the mechanical characteristic change is fixed. A second mode shape coefficient calculating means 34 for calculating the mode shape coefficient φbs of the countermeasure changing unit 10a in the state and a mode shape coefficient interpolation correcting means 35 are provided.

Further, the E-BBA vibration characteristic calculation means 4
Between the dynamic characteristics of the FEM model of the countermeasure structure section 10a before the change and the dynamic characteristics of the FEM model of the countermeasure structure section 10a after the change, which are obtained by the first and second FEM analysis means 2A, 2B. Change calculation program for calculating the change ΔM, ΔK of the dynamic characteristic, and the countermeasure component of the structure 10 obtained by the first and second FEM analysis means for the change of the dynamic characteristic by the E-BBA calculation theory. 10a to obtain the dynamic characteristics of the whole structure 10 after addition E
-BBA analysis program.

With the above structure, the structure 10
For the natural vibration mode (especially in the internal region excluding the connection point), the piecewise structure synthesis method (so-called CM
The concept of S) is used (see FIG. 8).

Next, a vibration measuring method (dynamic characteristic developing method) using the vibration measuring system of the embodiment of the present invention having the above-described structure will be described. In the method described below, for example, as shown in FIG. 5, there is a structure 10 such as a prototype actual power unit assembly for an automobile, and a configuration change portion such as an engine block portion (a countermeasure component portion) that is a constituent portion thereof.
When the mechanical characteristics of 10a are changed, the vibration of the structure 10 such as the changed power unit assembly (the changed power unit assembly incorporating the engine block) is measured and evaluated as accurately as possible. Is.

First, a predetermined load is applied by the vibrating means 6 to the entire structure 10 before changing the mechanical characteristics of the countermeasure components, and the overall vibration in the coupling region 10e of the structure 10 caused by the load ( The acceleration and the vibration of the countermeasure component 10a) are detected by the first and second vibration detecting means 36B and 36C such as an acceleration pickup. Such vibration detection is performed by the two component parts 10a, 10
For example, a few points of d. Then, the exciting force (F) given by the exciting means 6 and the vibration detecting means 36A, 36
The vibration accelerations (α ₁ ) and (α ₂ ) detected by B are temporarily stored in the data recording program of the data collecting means 11. Then, the data (F), (α ₁ , α ₂ ) is FFT.
Frequency analysis (ie, Fourier transform) is performed by the Fourier transform program of the frequency analysis means 12 having a (Fast Fourier Transform) function, and based on the frequency analysis (ie, Fourier transform), the entire structure (10a
+ 10d) and each transfer function of only the countermeasure component 10a, for example, a frequency-acceleration (α / F) curve is obtained. Next, the curve fit processing means 1 in the mode analysis unit 1C
By performing curve fitting processing on a specific peak of the transfer function by the curve fitting processing program of No. 4, modal parameters which are dynamic characteristics, that is, mode shapes (φA), (φB), modal mass (mo) and modal stiffness. (ko) Calculate the coefficient. The mode shape coefficients .phi.A and .phi.B among them are once input and stored in the first and second data memories 31 and 32.

On the other hand, by the FEM model creating programs of the first and second FEM analyzing means 2A and 2B,
Concerning the above-mentioned countermeasure components, the components before the countermeasure changes 10
FEM models (FIG. 6 and FIG. 7) of both a and the constituent part 10a ′ after the countermeasure change are created, and further FEM analysis is performed by each FEM analysis program, and the FEM model before the above countermeasure change (FIG. 6) Physical mass matrix [M] and physical stiffness matrix [K], which are the dynamic characteristics of, and the FEM model after countermeasure changes
The physical mass matrix [M '] and the physical stiffness matrix [K'], which are the dynamic characteristics of (Fig. 7), are obtained.

Next, the first and second mode shape coefficient calculating means 33, 3 of the mode shape coefficient interpolation correcting section 3 are described.
4 by the bonding region 10e of the structure 10 shown in FIG.
Each mode shape coefficient φ when and is not fixed
Calculate as and φbs respectively. Then, the calculated values φas, φbs
Using, the mode shape coefficient φ when the difference from the FEM analysis value becomes the minimum is corrected by the mode shape coefficient interpolation correcting means 35 and set.

Then, after the modal parameters such as modal mass mo and modal stiffness Ko except for the mode shape coefficient obtained by the curve fitting process and the FE before and after the countermeasure change obtained by the FEM analysis are performed.
The dynamic characteristics of the M model (physical mass matrix [M], [M '], physical stiffness matrix [K], [K'], etc. are supplied to the E-BBA vibration characteristic calculation means 4.

Then, after that, the E-BBA calculation means 4 is used.
Using the dynamic characteristic change calculation program, the change amount [ΔM] and [ΔK] of the above-mentioned dynamic characteristics of the constituent parts 10a and 10a ′ before and after the countermeasure change is calculated, and [ΔM] = − [M] + [M ′] [ ΔK] = − [K] + [K ′] These changes are obtained by the modal analysis means 1,
In addition, the modal parameters (φo, mo, Ko), which are the dynamic characteristics of the entire structure 10 before the measures are changed, which are corrected by the mode shape coefficient interpolation correction unit 3, are added based on the basic equation of E-BBA, and the Therefore, the structure 10 after the measures are changed
Find the modal parameters that are the dynamic characteristics of the whole.

The basic equation of this E-BBA will be described in detail below.

That is, in the above case, the matrix of physical mass and physical rigidity is as follows.

[M '] = [M] + [ΔM] ... (1) [K'] = [K] + [ΔK] ... (2) However, [M]: Before countermeasure change Physical mass matrix of the entire structure 10 [K]: physical rigidity matrix of the entire structure 10 before the measure change [M ′]: physical mass matrix of the entire structure 10 after the measure change [K ′]: after the measure change Physical rigidity matrix of entire structure 10 [ΔM]: Physical mass change matrix before and after countermeasure change [ΔK]: Physical rigidity change matrix before and after countermeasure change The above [ΔM] and [ΔK] are as follows. Can be asked. In other words, the physical mass and physical stiffness matrix before and after the change in countermeasures are shown in detail below.

[0100]

[Equation 2]

Therefore,

[0102]

(Equation 3)

Therefore, [ΔM] and [ΔK] are the configuration change parts 1
It is determined by the structure before and after the change of 0a.

On the other hand, the vibration equations before and after the above countermeasure changes are as follows.

[0105]

[Equation 4]

Therefore, the mode shape matrix [φo] can be obtained by eigenvalue analysis of [M] and [K]. And
Using this [φo],

[0107]

(Equation 5)

Is obtained.

Next, the following equation is obtained from the above equation (8).

[0110]

(Equation 6)

Then, the above equation (9) and (1), (2), (10)
From the equation, the following equation, which is the basic equation of E-BBA, is obtained.

[0112]

(Equation 7)

Therefore, it becomes possible to appropriately evaluate the vibration of the entire structure 10 after the countermeasure is changed.
(See Figures 9 and 10). That is, for example, as is clear from FIG. 9, according to the present embodiment, the correct value 227 Hz is 222 Hz, which is smaller than the conventional prediction error ΔA.

As described above, according to the vibration measuring system of the present embodiment, it is possible to surely smooth the proximity error of the mode shape coefficient by the experiment for the structure with a changed shape etc., and the prediction accuracy is greatly improved. It can be done.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a vibration measuring system according to a first embodiment of the present invention.

FIG. 2 is a diagram (conceptual configuration diagram) showing a structural model of a vibration measurement target structure in the first embodiment.

FIG. 3 is a block diagram showing a basic configuration of a vibration measuring system according to a second embodiment of the present invention.

FIG. 4 is a diagram (conceptual configuration diagram) showing a structural model of a vibration measurement target structure according to the second embodiment.

FIG. 5 is a block diagram showing a basic configuration of a vibration measuring system according to a third embodiment of the present invention.

FIG. 6 is a diagram (conceptual configuration diagram) showing a structural model of a vibration measurement target structure according to the third embodiment.

FIG. 7 is a diagram showing an FEM model after changing the shape and the like of the countermeasure component of the vibration measurement target structure in the third embodiment.

FIG. 8 is a vibration measurement principle (C in the third embodiment).
It is explanatory drawing which shows the concept of (MS).

FIG. 9 is experimental data for confirming the effect of improving the measurement accuracy of the vibration measurement system according to the third embodiment.

FIG. 10 is a characteristic diagram showing a prediction error correction effect in the primary vibration mode in comparison between the third embodiment and the conventional example.

FIG. 11 is an explanatory diagram of a model in a state before the structure is deformed, showing a problem of the conventional example.

FIG. 12 is an explanatory diagram of a model in a state after the structural deformation.

FIG. 13 is a graph showing the prediction accuracy of vibration characteristics based on experimental data using the models of FIGS. 11 and 12.

FIG. 14 is an FEM model diagram before changing the countermeasure component portion in the conventional example.

FIG. 15 is an FEM model after the modification.

[Explanation of symbols]

1A is a vibration experiment part, 1B is a signal processing operation part, 1C is a mode analysis part, 2 is an FEM analysis means, 2A is a first FEM analysis means, 2B is a second FEM analysis means, 3 is within a mode shape coefficient Insertion correction unit, 4A is BBA vibration characteristic calculation means,
4B is an E-BBA vibration characteristic calculation means, 5 is a sensitivity analysis means, 6 is a vibration means, 10 is a structure, 10a is a countermeasure constituent part, 10b is a non-change part, 11 is a data collection part, and 12 is a frequency conversion means. , 13 is a transfer function calculating means, 14 is a curve fitting processing means, and 35 is a mode shape coefficient interpolation correcting means.

Claims (4)

[Claims] 1. A vibration measurement system for determining a vibration characteristic of a whole structure after the mechanical characteristic is changed by a sensitivity analysis method when changing a mechanical characteristic of a countermeasure component of the structure. A vibration test is performed on the entire structure including a part, and a modal analysis is performed on the measured data of the entire structure obtained as a result of the vibration test to determine the sensitivity analysis area of the entire structure and the countermeasure component. And a modal analysis means for calculating respective vibration characteristics of the structure, and an FEM model of a region for which sensitivity analysis of the countermeasure component of the structure is desired to be created, and the created FEM model is subjected to FEM analysis to calculate the vibration characteristics. FEM analysis means, vibration characteristics of the FEM model calculated by the FEM analysis means, and the entire structure and sensitivity calculated by the modal analysis means In a vibration measurement system comprising sensitivity analysis means for calculating and predicting the vibration characteristics of the entire structure after changing the mechanical characteristics of the countermeasure constituent parts in combination with the respective vibration characteristics of the analysis area, a modal analysis by the modal analysis means is performed. Regarding the mode shape coefficient of the vibration characteristics obtained by analysis,
The data regarding the connection point in the virtual connection region between the region to be subjected to the sensitivity analysis of the structure and the other internal region is regarded as a true value, while the data in the internal region excluding the connection point is the vibration obtained by the FEM analysis means. The mode shape coefficient interpolating / correcting means for inputting the difference between the mode shape coefficient in the characteristics and the mode shape coefficient when the difference becomes the minimum as the correct mode shape coefficient to the sensitivity analyzing means is provided. A characteristic vibration measurement system. 2. A vibration measurement system for obtaining a vibration characteristic of the whole structure after the mechanical characteristic change by the BBA method when changing the mechanical characteristic of the countermeasure component of the structure. A vibration test was conducted on each component of the previous structure except the above countermeasure components, and the measured data for each component obtained as a result of the vibration test was subjected to a modal analysis to obtain the structure before the mechanical characteristic change. The modal analysis means for calculating the vibration characteristics of each component excluding the countermeasure component portion of the object and the FEM model of the countermeasure component portion after the mechanical characteristic change are created, and the created F
FEM analysis means for performing FEM analysis on the EM model to calculate the vibration characteristics thereof, and vibration characteristics of the FEM model of the countermeasure constituent part after the mechanical characteristics change calculated by the FEM analysis means and calculation by the modal analysis means BBA for calculating and predicting the vibration characteristics of the entire structure after the mechanical characteristics are changed by combining with the vibration characteristics of each component excluding the above-mentioned countermeasure components of the structure before the mechanical characteristics are changed.
In a vibration measurement system provided with a vibration characteristic calculation means, regarding a mode shape coefficient of the vibration characteristics obtained by the modal analysis by the modal analysis means, regarding the above-mentioned countermeasure constituent portion and non-countermeasure constituent portion of the structure. Data regarding the connection point in the virtual connection region is regarded as a true value, while the data in the internal region of the non-countermeasure constituent part excluding the connection point is the difference from the mode shape coefficient of the vibration characteristics obtained by the FEM analysis means. A vibration measuring system, characterized in that it is provided with a mode shape coefficient interpolation correcting means for obtaining the mode shape coefficient when the difference is minimized and inputting it to the BBA vibration characteristic calculating means as a correct mode shape coefficient. 3. A vibration measuring system for obtaining the vibration characteristics of the entire structure after the mechanical characteristics change by the E-BBA method when changing the mechanical characteristics of the countermeasure component of the structure. A modal analysis in which a vibration test is performed on the entire structure before the characteristics are changed, and the measured data obtained as a result of the vibration test is subjected to a modal analysis to calculate the vibration characteristics of the entire structure before the mechanical characteristics are changed. And FEM analysis means for creating FEM models of the above-mentioned countermeasure components before and after changing mechanical characteristics, and performing FEM analysis on each of the created FEM models to calculate respective vibration characteristics, and the FEM analysis means. Vibration which is the difference between the vibration characteristic of the FEM model of the countermeasure component before the mechanical characteristic change calculated by the above and the vibration characteristic of the FEM model of the countermeasure component after the mechanical characteristic change Of the entire structure after the mechanical characteristic change is calculated by adding the amount of change in the vibration characteristic to the vibration characteristic of the entire structure before the mechanical characteristic change calculated by the modal analysis means. In the vibration measurement system including the E-BBA vibration characteristic calculation means for calculating and predicting the above, regarding the mode shape coefficient of the vibration characteristics obtained by the modal analysis by the modal analysis means, the countermeasure component part of the structure. The data regarding the connection point in the virtual connection region between the non-countermeasure component and the non-countermeasure component part is regarded as a true value, while the data in the non-countermeasure component part-side internal region excluding the corresponding bond point is included in the vibration characteristics obtained by the FEM analysis means. The difference from the mode shape coefficient is calculated, and the mode shape coefficient when the difference is minimized is used as the correct mode shape coefficient in the above E-BB. A vibration measuring system, characterized by further comprising mode shape coefficient interpolation correcting means for inputting to the vibration characteristic calculating means. 4. The vibration characteristic calculation means is provided with a sensitivity analysis means as a post-processing means.
Alternatively, the vibration measurement system according to item 3.