CN1253623A

CN1253623A - Vibration exciting apparatus and vibration testing apparatus for structure using same

Info

Publication number: CN1253623A
Application number: CN 97182121
Authority: CN
Inventors: 桃井康行; 堀内敏彦; 梅北和弘; 井上雅彦; 今野隆雄; 菅野正治; 多田野有司
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1997-03-17
Filing date: 1997-03-17
Publication date: 2000-05-17
Anticipated expiration: 2017-03-17
Also published as: CN1207545C

Abstract

A vibration excitation testing apparatus for structures, which finds vibration response of a structure deforming in both of translational direction and rotational direction, and a vibration exciting apparatus used therefor. The vibration excitation testing appratus actually performs a vibration excitation testing for a part of a structure, performs numerical calculus of vibration response for the other part of the structure, and combines the two methods to find vibration response for the entire structure. Thus the vibration excitation testing apparatus comprises a multi-axis vibration exciting apparatus for causing vibration excitation of a prototype model in both of translational direction and rotational direction, means for calculating a position of point of exciting force from displacements of vibration exciting means, and means for calculating reaction forces from loads detected by load detecting means and the position of point of exciting force. Computting means computes a displacement of a numerical model in the next step using the reaction force calculated by a calculating means and known external forces, calculating means calculates a vibration exciter displacement command value on the basis of the displacement and drive means drives the vibration exciting means on the basis of an output from the calculating means.

Description

Vibration exciting device and structural vibration testing device using same

The present invention relates to a vibration excitation device capable of vibration excitation tests with multiple degrees of freedom, and to a vibration test device using a structure of such a device, so as to experimentally calculate a vibration excitation motion for a part of the structure, calculate a vibration excitation motion for the other part based on numerical calculation of vibration response, and calculate a vibration excitation motion for the entire structure by combining them.

An example of vibration testing of ｃA structure is described in JP- ｃA-5-10846, which experimentally performs vibration excitation testing of ｃA part of the structure, performs vibration response numerical calculation of the other part of the structure, and tests the entire structure by combining them. The method described in this publication uses a vibration exciting apparatus to perform vibration exciting tests in real time.

Here, as a vibration exciting apparatus for experimentally causing vibration excitation, mechanics was applied at 43 o' clockUnited academic seminar (43)^rdThe original report on Applied Mechanics Joint learning) (1993) page 581 describes a device for applying a load to an object under test in both a translational and rotational direction.

Here, the structure described in the above-mentioned japanese patent unexamined application publication No.5-10846 is assumed in the case where the prototype is deformed only in one direction, and any of the following assumptions is established. That is, (1) the rigidity of the floor in the building is large compared to the rigidity of the wall, and the bending deformation of the floor can be ignored. Furthermore, the rigidity of the wall against deformations in its surface is large compared to the rigidity of the wall against deformations outside its surface, so that the expansion and compression of the wall are negligible. (2) The prototype is supported with moments applied at both end portions of the prototype.

However, since an actual pipe, bridge, vibration damper, etc. correspond to a structure that deforms in both the translational direction and the rotational direction, it is necessary to perform vibration excitation of the prototype in both the translational direction and the rotational direction, whereas in the structure described in the above-mentioned japanese patent unexamined application No.5-10846, a structure that applies vibration excitation in both directions is not considered, and thus it is difficult to actually know the vibration excitation motion.

In the latter case, in which vibration excitation is possible for the translational and rotational directions of the prototype, on the other hand, the vibration exciter with large mass oscillation, and the inertial and elastic forces of the oil line, act as a disturbance for the vibration excitation. Then, there is a problem that the accuracy of the vibration excitation is lowered. Further, in this apparatus, since the vibration exciter is disposed inside the reaction frame, it is difficult to make the reaction frame compact and highly rigid.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a vibration exciting apparatus capable of testing a structure having deformation in both a translational direction and a rotational direction, and a vibration testing apparatus using the same.

It is another object of the present invention to provide a vibration exciting apparatus which has improved vibration exciting accuracy, compact size and high rigidity, and which can be used for a vibration testing apparatus.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a vibration testing apparatus for a structure, which is equipped with a vibration exciting apparatus for causing vibration excitation of a prototype of a part of a dummy structure, and a control calculating apparatus for calculating a vibration response of a numerical model conceived to be connected to the prototype, and which also performs vibration testing of the entire structure, wherein the vibration exciting apparatus is equipped with a plurality of vibration exciters for causing vibration excitation of the prototype, a plurality of displacement detectors for detecting displacements of the plurality of vibration exciters, and a load detector for detecting a load applied to the prototype, and the control calculating apparatus is equipped with a calculator for calculating displacements in a translational direction and a rotational direction of an excitation force point previously determined based on the load detected by the load detectors and the displacements of the vibration exciters detected by the plurality of displacement detectors, and a signal generator for generating a driving signal for driving the vibration exciter based on an output of the calculator.

According to a second aspect of the present invention for achieving the above object, there is provided a vibration testing apparatus equipped with a vibration exciting apparatus for causing vibration excitation to a prototype which is a part of a simulation structure, and a digital calculator for calculating a vibration response of a numerical model conceived to be connected to the prototype, and performing vibration testing of the entire structure, wherein the vibration exciting apparatus is equipped with a plurality of vibration exciters, and the plurality of vibration exciters are configured such that translational displacement and rotational displacement are simultaneously applied to the prototype.

The vibration exciter arrangement thus preferably has at least three vibration exciters and comprises a horizontal vibration exciter for inducing vibration excitations in the horizontal direction and a vertical vibration exciter for inducing vibration excitations in the vertical direction, and has at least two joints for structurally connecting the vibration exciter to the prototype; each having a horizontal link connected to a horizontal vibration exciter, a vertical link connected to a vertical vibration exciter, and at least one horizontal link and at least one vertical link connected to a joint; a joint holder provided with a load detector capable of detecting loads in at least two different directions is provided between the joint holder and the joint; a joint holder for mounting a prototype is mounted to the joint, and a load detector capable of detecting at least any one of loads in two different directions and a moment about an axis is mounted on the joint holder; a vibration exciting point position calculator for calculating an exciting force point position from a plurality of vibration exciter displacements, a vibration exciting point acceleration estimator for estimating an exciting force point acceleration based on at least any one of a displacement, a velocity, and an acceleration of the vibration exciter, and a reaction force calculating means for calculating a reaction force of a prototype based on the acceleration estimated by the vibration exciting point acceleration estimator, a load detected by the load detector, and the position of the exciting force point calculated by the vibration exciting point position calculator are provided; and is equipped with at least one of an acceleration detector and an angular acceleration detector, a vibration excitation point velocity and acceleration calculator for calculating the acceleration of the excitation force point based on the detection value of any of the detectors, a vibration excitation point position calculator for calculating the position of the excitation force point, and a reaction force calculator for calculating the reaction force of the prototype based on the load detected by the load detector, the position of the excitation force point calculated by the vibration excitation point position calculator, and the acceleration of the excitation force point calculated by the vibration excitation velocity and acceleration calculator.

According to a third aspect of the present invention for achieving the above object, there is provided a vibration exciting apparatus having a plurality of vibration exciters for causing vibration excitation of an object under test and a frame for mounting the vibration exciters, wherein the plurality of vibration exciters are configured such that a translational displacement and a rotational displacement are simultaneously applied to the object under test.

Therefore, it is preferable to provide at least three vibration exciters, and include a horizontal vibration exciter for causing vibration excitation in the horizontal direction and a vertical vibration exciter for causing vibration excitation in the vertical direction; providing at least two joints capable of making a structural connection between the object under test and the vibration exciter; connecting the horizontal links to the horizontal vibration exciters and the vertical links to the vertical vibration exciters, respectively, with at least one horizontal and at least one vertical link connected to the joint; a joint holder for fixing a joint is provided, and a load detector capable of detecting loads in at least two different directions and moments about an axis is provided in the joint holder; there are provided a vibration excitation point acceleration estimator for estimating an acceleration of an excitation force point based on at least any one of a displacement, a velocity, and an acceleration for a horizontal vibration exciter and a vertical vibration exciter, a vibration excitation point position calculator for calculating a position of the excitation force point from the displacements of the horizontal vibration exciter and the vertical vibration exciter, and a reaction force calculator for calculating a reaction force from the test object based on the load detected by the load detector, the position of the excitation force point calculated by the vibration excitation point position calculator, and the acceleration of the excitation force point estimated by the vibration excitation point acceleration estimator; and at least either one of an acceleration detector and an angular acceleration detector, a vibration excitation point velocity and acceleration calculator for calculating an acceleration of the excitation point based on a detection value of any of the detectors, a vibration excitation point position calculator for calculating a position of the excitation point, and a reaction force calculator for calculating a reaction force of the prototype based on the load detected by the load detector, the position of the excitation point calculated by the vibration excitation point position calculator, and the acceleration of the excitation point calculated by the vibration excitation velocity and acceleration calculator are provided.

FIG. 1 is a schematic view of a first embodiment of a vibration testing apparatus according to the present invention;

FIG. 2 is a schematic view of an embodiment of a multi-axis vibration excitation device according to the present invention;

fig. 3 is a diagram for explaining details of a load detector in the multi-axis vibration excitation device shown in fig. 2;

FIG. 4 is a diagram illustrating excitation force points according to the present invention;

FIG. 5 is a schematic view of another embodiment of a vibration testing apparatus according to the present invention;

FIG. 6 is a schematic view of yet another embodiment of a vibration testing apparatus according to the present invention;

fig. 7 is a schematic diagram of another embodiment of a load detector.

Hereinafter, certain embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 to 3 relate to a first embodiment of a vibration testing system according to the present invention, in which fig. 1 is a schematic view of a vibration testing apparatus for a structure, fig. 2 is a diagram showing an embodiment of a vibration exciting apparatus for the vibration testing apparatus shown in fig. 1, and fig. 3 is a diagram showing details of a load detector used in fig. 2. The vibration testing apparatus according to the present invention performs a vibration excitation test on a portion of a structure under test and numerically models other portions of the structure using a prototype obtained by modeling a real size or a small size, and performs a vibration response calculation on the numerically modeled portion. The two results are then combined and the vibration response of the entire structure is estimated. Thus, in the present embodiment, there is provided a multi-axis vibration excitation device 110 having a plurality of

vibration exciters

1, 2 and 3, joints for transmitting displacements of the vibration exciters to a prototype 14 mounted on a base 15, a holder 6 for arranging the joints and a load detector 12 from the prototype 14 to the

vibration exciters

1, 2 and 3, and a control calculation device 100 which controls the multi-axis vibration excitation device 110 and has a digital calculator or an analog calculator for calculating a numerical model vibration response. Then, each of the

vibration exciters

1, 2 and 3 is equipped with a

cylinder

1b, 2b and 3b, a

drive shaft

1a, 2a and 3a, and a

displacement detector

1c, 2c and 3 c.

The control computing device 100 is equipped with each of the following devices. Namely, a vibration exciting position calculator 101 for calculating the position of an exciting force point 16 located at a boundary portion between the numerical model and the prototype 14 based on the displacement of each

vibration exciter

1, 2 and 3, a reaction force calculator 102 for calculating a reaction force generated in the prototype 14 based on the load detected by the load detector 12 and the position of the point 16 of the excitation force 16, a vibration response calculator 103 for calculating the displacement of the numerical model 14 after a predetermined time has elapsed based on the reaction force generated in the prototype 14 and the known external force, a vibration exciter displacement calculator 104 for calculating a displacement command value for each of the

vibration exciters

1, 2 and 3 from the position command value of the excitation force point 16, and a vibration exciter controller 105 for operating the

vibration exciters

1, 2 and 3 in accordance with the displacement command value to the

vibration exciters

1, 2 and 3.

In this case, one of the features of the present invention is that an excitation force point capable of applying both rotational displacement and translational displacement is provided. The excitation force point 16 is selected from a point that explicitly represents the prototype deformation or a point corresponding to this point 1 to 1. That is, if the displacement of the prototype is calculated from the displacement of the point with high accuracy when the excitation force point is optionally selected, the point can be set as the excitation force point. For example, in the case of performing a vibration excitation test on the structure shown in fig. 1, the pillar portion is set as a prototype, and the upper portion thereof is set as a numerical model. A method of selecting the excitation force point at this time will be described below with reference to fig. 4. The intersection point between the neutral axis 20 formed in the prototype 14 and the boundary surface between the numerical model and the prototype is set as a boundary point. In the simplified model shown in fig. 1, the boundary points are selected as excitation force points in the simplest case, since the neutral axis corresponds to the point that best represents the deformation of the model. However, the boundary point corresponds to a point inside in fig. 1, and it is difficult to actually measure the displacement thereof. In the case of measuring displacement for controlling the

actuators

1, 2 and 3, etc., it is preferably a point on the surface of the device. In this case, the excitation force point 16 can be provided on the splice holder 6. However, in this case, the conversion of the displacement to the boundary point must be calculated. On the contrary, in the case of a complex shape, it is a case that it is difficult to select a neutral axis. In this case, if there is a neutral axis on the equivalent model, it is preferable to select a point on the neutral axis in the equivalent model. If it is difficult to select the neutral axis even in an equivalent model, it is preferable to select a geometric center point or the like. In each case, as long as a point capable of representing the displacement of the prototype is not involved, conversion, calculation, or the like is not necessary, it can be used as the excitation force point.

Hereinafter, an embodiment of controlling processing content in the computing apparatus 100 will be described based on an operation procedure.

(1) The multi-axis vibration exciting means 110 is used to move and excite the prototype 14 in the translational direction and the rotational direction, thereby inputting the load detected from the load detector 12 to the control computing means 100.

(2) The displacements of the vibration

exciting machines

1, 2, and 3 related to the detected load are also input to the control calculating device 100, and the vibration exciting point position calculator 101 calculates the position of the exciting force point 16 based on the displacements of the vibration

exciting machines

1, 2, and 3.

(3) The reaction force calculator 102 calculates the reaction force generated in the prototype 14 based on the load detected by the load detector 12 and the position of the excitation force point 16 calculated in item (2).

(4) The vibration response calculator 103 calculates the displacement of the numerical model in the next step corresponding to the step after the predetermined time based on the reaction force calculated in item (3) and the known external force.

(5) By extracting the displacement of the excitation force point 16 among the displacements of the numerical model obtained in the item (4) as the boundary portion between the prototype 14 and the numerical model, the vibration excitation point position calculator 104 calculates the displacement command value of each of the

vibration exciters

1, 2, and 3 based on the displacement.

(6) According to the vibration exciter displacement command value calculated in the item (5), the vibration exciter controller 105 drives the

vibration exciters

1, 2 and 3, and as a result, the multi-axis vibration exciting device 110 displaces and excites the prototype 14.

The above-described processes from (1) to (6) are repeated. Thus, even when the belonging structure is displaced in both the translational direction and the rotational direction, its vibration response can be obtained.

Hereinafter, an embodiment of a multi-axis vibration exciting apparatus for a local vibration excitation testing apparatus will be described with reference to fig. 2. The multi-axis vibration exciting means 110 has

side walls

4 and 4 fixed to the base 15, which face the two side edges of the prototype 14 to each other. Then, a top plate 5 is arranged on top of the prototype 14, so that it connects the two

side walls

4 and 4. The side walls 4 and the top plate 5 constitute a reaction force frame. The horizontal vibration exciter 1, which has the drive shaft side of the vibration exciter cylinder fixed to the side wall 4, has a joint 8 in the drive shaft. Then, the horizontal vibration exciter 1 is configured such that the vibration exciter cylinder does not enter the inside of the reaction force frame. Likewise, the

vertical vibration exciters

2 and 3 having the joint 9 in the drive shaft are constructed such that the drive shaft side of the cylinder of the vibration exciters is fixed to the top plate 5 and the cylinder of each vibration exciter is disposed so as not to enter the inside of the reaction force frame. Furthermore, the joint holder 6 is attached on the upper surface of the prototype 14, and the joint 7 is attached to the prototype 14 through the joint holder 6.

As the joint holder 6, a structure formed in a plate shape is used in fig. 2, however, the shape, number, and mounting position thereof are not limited thereto, and can be appropriately provided as individually needed. Furthermore, the joint holder 6 contains the structure for mounting the joint 7 provided by the prototype 14 itself. Further, the joint 7 mounted to the prototype 14 is constituted by two in fig. 2, however, the shape, degree of freedom, number, and mounting position thereof are not limited to the case of the joint holder 6.

One of the joints 7 of the prototype 14 and the joint 8 of the drive shaft of the horizontal vibration exciter are connected by a horizontal link 10. One of the joints 7 of the prototype and the joint 9 of the drive shaft mounted to the vertical vibration exciter are connected by a vertical link 11. In the multi-axis vibration excitation device 110 according to the present embodiment, the displacement of each of the horizontal vibration exciter 1 and the

vertical vibration exciters

2 and 3 is transmitted to the joint 7 mounted on the prototype 14 through the horizontal link 10 and the vertical link 11. As a result, prototype 14 is excited.

In the multi-axis vibration exciting apparatus 110 shown in the above embodiment, since only the respective vibration

exciter drive shafts

1a, 2a and 3a, the horizontal link 10, the vertical link 11, the load detector 12, the joint holder 6 and the prototype-side joint 7 are provided as movable parts, the entire mass is smaller than that obtained by combining the horizontal vibration exciter 1 and the

vertical vibration exciters

2 and 3. The inertial force generated at the time of vibration excitation can thus be greatly reduced as compared with the conventional structure in which the entire vibration exciter oscillates. Further, in the conventional art, since the piping for supplying the oil hydraulic pressure to each vibration exciter operates in correspondence with the oscillation of the vibration exciter, the elastic force of the piping acts as a disturbing action of the vibration excitation. In contrast, in the present embodiment, since the vibration exciter cylinder is fixed to the reaction force frame, the pipe is not moved and does not exert an influence on the vibration excitation. As described above, according to the present embodiment, since the disturbance caused by the inertial force of the movable portion and the elastic force of the oil pipe can be reduced, the accuracy of the vibration excitation is improved.

Further, since the horizontal vibration exciter and the vertical vibration exciter are conventionally disposed inside the reaction force frame, it is necessary to construct a large-sized reaction force frame. However, according to the present embodiment, since the vibration exciter cylinder can be arranged outside the reaction force frame, it is only necessary to arrange the reaction force frame so that the horizontal links 10 and the vertical links 11 can be disposed, and thus the length of each link can be made shorter than the length of the vibration exciter cylinder. Thus, the reaction force frame can be made compact and thus made highly rigid.

Hereinafter, a description will be given of a correspondence relationship between the displacement of the vibration exciter and the position of the excitation force point, which is necessary for the case of excitation with reference to the above-described embodiment.

First, the displacement of the horizontal vibration exciter 1 and the displacements of the

vertical vibration exciters

2 and 3 are calculated based on the position of the excitation force point 16And (4) displacing. The number of the horizontal vibration exciters is one, and the number of the vertical vibration exciters is two. Further, the number of bonding points on the prototype 14 side is two. In this case, each displacement can be calculated by equation 1.

l_{1} = - (x_{r} - b) + (a_{1} - \sqrt{{a_{1}}^{2} - {z_{r}}^{2}})

l_{2} = - z_{r} + (a_{2} - \sqrt{{a_{2}}^{2} - {(x_{r} - b)}^{2}})

l_{3} = - z_{1} + (a_{2} - \sqrt{{a_{2}}^{2} - {(x_{1} + b)}^{2}})

(formula 1)

Wherein,

Xr＝X-dzsinθy+bcosθy

Zr＝Z-dz(1-cosθy)+bsinθy

Xl＝X-dzsinθy-bcosθy

zl ═ Z-dz (1-cos θ y) -bsin θ y (formula 2)

Wherein,

x, Z, θ y: location of excitation force point

11: displacement of the horizontal vibration exciter 1

12: displacement of the vertical vibration exciter 2

13: displacement of the vertical vibration exciter 3

a 1: length of horizontal connecting rod

a 2: length of vertical connecting rod

2 b: spacing of prototype side bond points (see FIG. 3)

dz: height of the joint holder (see FIG. 4)

By using the above formula, the displacements of the

vibration excitators

1, 2 and 3 can be unambiguously calculated on the basis of the position of the excitation force point 16. Further, when the total number of the horizontal vibration excitators and the vertical vibration excitators is three or more and the number of the prototype 14-side bonding points is two or more, the displacement of the vibration excitators can be definitely determined based on the positions of the excitation force points according to the above-described method.

Then, the structure is formed such that the total number of the horizontal vibration excitators and the vertical vibration excitators is three or more and the number of the prototype-side bonding points is two or more, thereby enabling the displacement of the vibration excitators to be definitely calculated based on the positions of the excitation force points. Then, the amount of deformation applied to both the translational direction and the rotational direction of the prototype can be determined unambiguously.

On the contrary, based on the displacement of the horizontal vibration exciter 1 and the displacements of the

vertical vibration exciters

2 and 3, the position of the excitation force point can be calculated. In the following, consider the situation shown in fig. 2, where at least one horizontal link and at least one vertical link are connected to any joint on the prototype side at the same time. At this time, the position of the excitation force point can be calculated based on equation 3.

x＝x_r-bcosφ_y+d_zsinθ_y

z＝z_r-bsinφ_y-d_zcosθ_y+d_r

- ta n^{- 1} \frac{a_{2} - l_{3} - z_{r}}{x_{r} + b}

(formula 3)

Wherein,

x_r＝b+a₁-l₁-a_rcosφ₁

z_r＝a_rsinφ₁

(formula 4)

According to the method, the position of the excitation force point can be strictly calculated based on the displacements of the horizontal vibration exciter and the vertical vibration exciter.

As described above, in the vibration testing apparatus according to the present embodiment, the control calculation means 100 for calculating the position of the excitation force point based on the displacements of the horizontal vibration excitator and the vertical vibration excitator is necessary. However, in the case where the displacement of each vertical vibration exciter cannot be strictly calculated, the approximation calculation and the convergence calculation may be performed, however, in this case, in view of the accuracy of the operation and the operation time, insufficient results may be caused. Thus, if a rigorous solution can be obtained, the problem can be solved and the accuracy of the test improved.

Hereinafter, an embodiment of calculating the reaction force generated in prototype 14 will be described with reference to fig. 3. Fig. 3 is a detailed view of the joint holder 6 shown in fig. 2.

Load detectors

12a and 12b for detecting two orthogonal direction loads are arranged between the prototype-side joint holder 6 and the joint 7.

The method of calculating the reaction force at this time is as follows. Upon vibrational excitation, the joint holder 6, the prototype-side joint 7, and the

load detectors

12a and 12b are excited simultaneously, and thus an inertial force, a centrifugal force, and coriolis (coriolis's) force are generated in each device. When a force for rotating the prototype 14 is applied, the joint holder 6, the prototype-side joint 7, and the load detector 12 generate an overturning moment due to the relative empty weight. The inertial force, centrifugal force, coriolis force, and overturning moment generated by the vibration excitation are superimposed on the reaction force from the prototype 14 and detected at the

load detectors

12a and 12 b. The reaction force generated in the prototype 14 can then be obtained by subtracting the components of the inertial force, centrifugal force, coriolis force, and overturning moment from the detection values of the

load detectors

12a and 12 b. The reaction force generated in the prototype is represented by equation 5.

F_x＝(f_1x+f_2x)cosθ_y-(f_1z+f_2z)sinθ_y

F_z＝(f_1x+f_2x)sinθ_y+(f_1z+f_2z)cosθ_y

M_y＝(f_1z-f_2z)_b-(f_1x+f_2x)d_z

<math> <mrow> <mo>+</mo> <mrow> <mo>(</mo> <msub> <mi>I</mi> <mn>1</mn> </msub> <mo>+</mo> <mi>mth</mi> <msup> <mi>t</mi> <mn>2</mn> </msup> <mo>)</mo> </mrow> <msub> <mover> <mi>θ</mi> <mrow> <mo>.</mo> <mo>.</mo> </mrow> </mover> <mi>y</mi> </msub> <mo>-</mo> <mi>mtht</mi> <mi>cos</mi> <msub> <mi>θ</mi> <mi>y</mi> </msub> <mo>·</mo> <mover> <mi>x</mi> <mrow> <mo>.</mo> <mo>.</mo> </mrow> </mover> <mo>-</mo> <mi>mtht</mi> <mi>sin</mi> <msub> <mi>θ</mi> <mi>y</mi> </msub> <mo>·</mo> <mover> <mi>z</mi> <mrow> <mo>.</mo> <mo>.</mo> </mrow> </mover> <mo>-</mo> <mi>mtght</mi> <mi>sin</mi> <msub> <mi>θ</mi> <mi>y</mi> </msub> </mrow> </math>

(formula 5)

Wherein,

fx, Fz, My: reaction forces generated in the prototype

f1x, f1z, f2x, f2 z: load detected by load detector

Acceleration of excitation point

mt: total mass of joint holder, joint and load detector

It: moment of inertia about the overall center of gravity of the joint holder, joint and load detector

ht: height from lower surface of the joint holder to overall center of gravity of the joint holder, joint, and load detector

g: acceleration of free falling body

According to the present embodiment, since the load detector 12 is disposed between the joint holder 6 and the joint 7, the reaction force of the prototype 14 can be obtained. In this case, when the load detector 12 is disposed at the above-described position, the number of components present between the prototype 14 and the load detector is reduced, and thus it is possible to reduce the influence of the inertial force, the centrifugal force, the coriolis force, the no-load force, and the unnecessary component frictional force on the load detection value and obtain the reaction force with high accuracy.

In this case, as shown in equation 5, in order to calculate the reaction force generated in the prototype 14, values of the inertial force, the centrifugal force, the coriolis force, and the overturning moment acting on the joint holder 6, the joint 7, and the load detector 12 are necessary in addition to the load detected in the load detector 12. Among them, when the position of the excitation force point 16 can be known, the overturning moment can be calculated. Conversely, the inertial force, the centrifugal force, and the coriolis force can be calculated when the acceleration of the excitation force point 16 is known. At this point, an embodiment of the control calculation device 100 in which these quantities are calculated and their influence compensated for will be shown in fig. 5.

In the control calculation device 100, a vibration excitation point velocity estimator 106a for estimating the velocity at the excitation force point 16 based on the displacement of the vibration exciter, and a vibration excitation point acceleration estimator 106b for estimating the acceleration are provided. In the reaction force calculator 102, a reaction force is calculated using formula 5 based on the load detected by the load detector 12, the position of the excitation force point calculated by the vibration excitation point position calculator 101, the velocity of the excitation force point estimated by the vibration excitation point velocity estimator 106a, and the acceleration estimated by the vibration excitation point acceleration estimator 106 b. At this time, according to the above-described method, the inertial force, the centrifugal force, the coriolis force, and the overturning moment are compensated. In the vibration excitation point velocity estimator 106a and the vibration excitation point acceleration estimator 106b, the velocity and acceleration of the excitation point are estimated from the displacement, velocity, and acceleration of the vibration exciter, for example, by differentiating the excitation point position obtained based on the displacement of the vibration exciter and using an observer. According to the present embodiment, since the velocity can be estimated by the vibration excitation point velocity estimator 106a and the acceleration can be estimated by the vibration excitation point acceleration estimator 106b, the inertial force, the centrifugal force, the coriolis force can be compensated, and the reaction force can be obtained with high accuracy.

A third embodiment according to the present invention will be explained below with reference to fig. 6. The present embodiment differs from the second embodiment in that an acceleration detector 13a and an angular velocity detector 13b are provided in the joint holder 6 so as to obtain the excitation force point velocity and acceleration. The velocity and acceleration of the excitation force point can be obtained with high accuracy using the outputs of the acceleration detector 13a and the angular velocity detector 13 b. In this case, the acceleration detector 13a and the angular velocity detector 13b may be separate bodies or may be integrated. Further, the angular velocity can be calculated based on the value detected by the acceleration detector 13 a. Also, an angular acceleration detector 13c may be provided in addition to the angular velocity detector 13 b. In this case, the velocity and acceleration of the excitation force point can be calculated in a comparatively simple manner.

The vibration excitation point velocity and acceleration calculator 107 calculates the velocity and acceleration of the excitation force point 16 based on the acceleration and angular velocity detected by the acceleration detector 13a and the angular velocity detector 13b, respectively. The reaction force calculator 102 compensates for the inertial force, the centrifugal force, the coriolis force, and the overturning moment based on the load detected by the load detector 12, the position of the excitation force point 16 calculated by the vibration excitation point position calculator 101, and the velocity and acceleration of the excitation force point 16 calculated by the vibration excitation point velocity and acceleration calculator 107, and calculates the reaction force according to equation 5. In this case, for example, in the vibration excitation point velocity and acceleration calculator 107, the acceleration and angular velocity detected by the acceleration detector 13a and the angular velocity detector 13 are subjected to coordinate system transformation, respectively.

According to the present embodiment, since the acceleration detector 13a and the angular velocity detector 13b are provided in the engagement point holder 6, and the means 107 for calculating the velocity and the acceleration of the excitation force point based on the detected acceleration and angular velocity is provided in the control calculation device 100, the inertial force can be compensated for the reaction force measured by the reaction force measurer, and thus the reaction force can be obtained with higher accuracy. In this case, in the above-described embodiment, the angular acceleration is calculated based on the detected value of the angular velocity, however, when the detector for detecting the angular acceleration is provided independently, the velocity and the acceleration of the excitation force point can be obtained with higher accuracy.

Further, other embodiments of the vibration testing apparatus according to the present invention will be described below. A load detector 12 for detecting two loads in the orthogonal cross direction and a moment around an axis crossing the orthogonal load detection direction is provided between the joint holder 6 and the prototype 14. Details of the splice point holder 6 are shown in figure 8. In the present embodiment thus configured, the reaction force can be calculated based on equation 6.

Fx＝fxcosθy-fzsinθy

Fz＝fxsinθy+fzcosθy

My is My (equation 6)

Wherein,

fx, fz, my: load detected by load detector

According to the present embodiment, in the same manner as each of the embodiments described above, the reaction force can be detected with high accuracy.

In each of the above embodiments, the multi-axis vibration excitation means is capable of inducing vibration excitation to the object under test in both the translational direction and the rotational direction based on a predetermined input signal. Further, the vibration testing apparatus has functions necessary for the vibration excitation test, such as conversion from the position of the excitation force point to the displacement of the vibration exciter, conversion from the displacement of the vibration exciter to the excitation force point corresponding to the reverse conversion thereof, detection of a reaction force in the object under test, and the like.

According to the present invention, even in the case where the structure is deformed in both the translational direction and the horizontal direction, it is possible to perform the vibration test of the entire structure with high accuracy by actually performing the vibration excitation test of a part of the structure and combining the calculation of the vibration response of the other part of the structure. At this time, it is possible to provide a multi-axis vibration excitation device which can improve the accuracy of vibration excitation in a vibration excitation test and can be used in a vibration testing device having a compact size and high rigidity.

The invention is capable of other embodiments within its scope and its central characteristics. Accordingly, the described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is indicated by the appended claims, and all modified embodiments within the claims are intended to be embraced therein.

Claims

1. A vibration testing apparatus for a structure, the apparatus being provided with vibration exciting means for inducing vibration excitation to a prototype which simulates a portion of the structure, and control calculating means for calculating a vibration response of a numerical model conceived to be connected to the prototype, the apparatus also performing vibration testing of the entire structure,

wherein the vibration exciting apparatus is equipped with a plurality of vibration exciters for causing vibration excitation of a prototype, a plurality of displacement detectors for detecting displacements of the plurality of vibration exciters and a load detector for detecting a load applied to the prototype, and the control computing means is equipped with a calculator for calculating displacements in a translational direction and a rotational direction of an excitation force point previously determined based on the load detected by the load detectors and the displacements of the vibration exciters detected by the plurality of displacement detectors, and a signal generator for generating a drive signal for driving the vibration exciters based on an output of the calculator.

2. A vibration testing apparatus for a structure, which is equipped with a vibration exciting apparatus for inducing vibration excitation to a prototype which is a part of a dummy structure, and a digital calculator for calculating a vibration response of a numerical model conceived to be connected to the prototype, and performs vibration testing of the entire structure,

wherein said vibration exciting means is equipped with said plurality of vibration exciters, and said plurality of vibration exciters are configured so that a translational displacement and a rotational displacement are simultaneously applied to said prototype.

3. A vibration testing apparatus for a structure as claimed in claim 2, wherein said vibration exciting means has at least three of said vibration exciters, and includes a horizontal vibration exciter for causing vibration excitation in a horizontal direction and a vertical vibration exciter for causing vibration excitation in a vertical direction, and has at least two joints for structural connection between said vibration exciters and the prototype.

4. The vibration testing apparatus for a structure as claimed in claim 3, wherein horizontal links are connected to the horizontal vibration exciter and vertical links are connected to the vertical vibration exciter, respectively, and at least one horizontal link and at least one vertical link are connected to the joint.

5. A vibration testing apparatus for a structure as claimed in claim 3, wherein a joint holder for fixing a joint to said vibration exciting means is provided, and a load detector capable of detecting loads in at least two different directions is provided between the joint holder and said joint.

6. A vibration testing apparatus for a structure as claimed in claim 3, wherein a joint holder for mounting said prototype is mounted to said joint, and a load detector capable of detecting at least any one of loads in two different directions and moments about an axis is provided on the joint holder.

7. A vibration testing apparatus for a structure as set forth in claim 3, wherein a vibration exciting point position calculator for calculating an exciting force point position from displacements of said plurality of vibration exciters, a vibration exciting point acceleration estimator for estimating an exciting force point acceleration based on at least any one of a displacement, a velocity, and an acceleration of said vibration exciter, and a reaction force calculating means for calculating a reaction force of said prototype based on an acceleration estimated by said vibration exciting point acceleration estimator, a load detected by said load detector, and a position of said exciting force point calculated by said vibration exciting point position calculator are provided.

8. A vibration testing apparatus for a structure as set forth in claim 3, wherein at least one of an acceleration detector and an angular acceleration detector, a vibration excitation point velocity and acceleration calculator for calculating an acceleration of an excitation force point based on a detection value of any of the detectors, a vibration excitation point position calculator for calculating a position of said excitation force point, and a reaction force calculator for calculating a reaction force of said prototype based on a load detected by said load detector, a position of said excitation force point calculated by said vibration excitation point position calculator, and an acceleration of said excitation force point calculated by said vibration excitation velocity and acceleration calculator are installed.

9. A vibration exciting apparatus having a plurality of vibration exciters for causing vibration excitation of an object to be tested and a frame for mounting the vibration exciters, wherein the plurality of vibration exciters are configured so as to simultaneously impart translational displacement and rotational displacement to the object to be tested.

10. A vibration excitation device as claimed in claim 9, wherein at least three of said vibration exciters are provided, and comprise a horizontal vibration exciter for causing vibration excitation in a horizontal direction and a vertical vibration exciter for causing vibration excitation in a vertical direction.

11. A vibration exciting apparatus according to claim 10, wherein at least two joints capable of making a structural connection between the object to be tested and said vibration exciter are provided.

12. A vibration exciting apparatus as claimed in claim 11, wherein a horizontal link is connected to said horizontal vibration exciter and a vertical link is connected to said vertical vibration exciter, respectively, and at least one of the horizontal and at least one of the vertical links are connected to said joint.

13. The vibration excitation device as claimed in claim 12, wherein an engagement point holder for holding said engagement point is provided, and a load detector capable of detecting loads in at least two different directions and moments about an axis is provided in the engagement point holder.

14. The vibration exciting apparatus according to claim 12, wherein there are provided a vibration exciting point acceleration estimator for estimating an acceleration of an exciting force point based on at least any one of a displacement, a velocity and an acceleration for said horizontal vibration exciting machine and said vertical vibration exciting machine, a vibration exciting point position calculator for calculating an exciting force point position from the displacements of said horizontal vibration exciting machine and said vertical vibration exciting machine, and a reaction force calculator for calculating a reaction force from the tested object based on the load detected by said load detector, the exciting force point position calculated by said vibration exciting point position calculator and the acceleration of the exciting force point estimated by said vibration exciting point acceleration estimator.

15. The vibration excitation device as set forth in claim 12, wherein at least either one of an acceleration detector and an angular acceleration detector is provided, a vibration excitation point velocity and acceleration calculator for calculating an acceleration of the excitation force point based on a detection value of any detector, a vibration excitation point position calculator for calculating a position of the excitation force point, and a reaction force calculator for calculating a reaction force of the prototype based on the load detected by the load detector, the position of the excitation force point calculated by the vibration excitation point position calculator, and the acceleration of the excitation force point calculated by the vibration excitation velocity and acceleration calculator.