CN1207545C - Vibration exciting apparatus and vibration testing apparatus for structure using same - Google Patents

Abstract

The present invention relates to a vibration excitation testing device and a vibration excitation device used for the vibration excitation testing device. The vibration excitation testing device is used for looking for structural vibration responses which deform in the translation direction and the rotation direction in a structural mode. The vibration excitation testing device actually carries out a part of the vibration excitation testing in a structural mode, carries out the numerical calculation of the vibration responses of other parts in a structural mode, and combines the two methods so as to look for the vibration response of the entire structure; thereby, the vibration excitation testing device comprises a multiaxial vibration excitation device (110), a device (101) and a device (102), wherein the multiaxial vibration excitation device (110) is used for provoking prototype (14) vibration excitation in the translation direction and the rotation direction; the device (101) is used for calculating the position of the excitation force (16) point according to the shifts of the vibration exciter (1, 2, 3); the device (102) is used for calculating the reaction force according to loads detected by load detectors (12a, 12b) and the position of the excitation force (16) point. Then, a calculator (103) calculates the shift of the numerical model through the known external force and the reaction force which is calculated by a calculator (102), a calculator (104) calculates the shift command value of the vibration exciters on the basis of the shift, and a driving device (105) drives the vibration exciters (1, 2, 3) on the basis of the output of the calculator (104).

Description

Vibration exciting device and structural vibration testing device using same

Technical Field

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.

Background

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

Here, as a vibration exciting means for experimentally causing vibration excitation, at 43The joint mechanics lecture (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.

Disclosure of Invention

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 deformed 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 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 vibration exciting means for causing vibration excitation to a prototype imitating a part of the structure and control calculating means for calculating a vibration response of a numerical model conceived to be connected to the prototype, the vibration testing apparatus thereby performing vibration testing of the entire structure, wherein the vibration exciting means 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 actuators and a load detector for detecting a load applied to the prototype, and the control calculation means is equipped with a calculator for calculating displacements of predetermined excitation force points in the translational direction and the rotational direction based on the load detected by the load detectors and the displacements of the vibration actuators detected by the plurality of displacement detectors, and a signal generator for outputting drive signals corresponding to the calculated displacements of the excitation force points in the translational direction and the rotational direction to the vibration actuators, thereby generating displacements in the calculated translational direction and the rotational direction of the excitation force points.

According to a second aspect of the present invention there is provided a vibration testing apparatus for a structure, which apparatus is provided with vibration exciting means for causing vibration excitation to a prototype which simulates a portion of the structure and control calculating means for calculating the vibration response of a numerical model conceived to be connected to the prototype, and performs vibration testing of the entire structure, wherein the vibration exciting means is provided with a plurality of vibration exciters, and the plurality of vibration exciters are arranged so as to apply both translational displacement and rotational displacement to points at which the vibration exciters are mounted.

The vibration exciter arrangement preferably has at least three vibration exciters and comprises a horizontal vibration exciter for inducing vibration excitation in a horizontal direction and a vertical vibration exciter for inducing vibration excitation in a vertical direction, and has at least two joints for structural connection between the vibration exciter and 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; an engagement point holder for holding the engagement point to the vibration exciting means is provided, and a load detector capable of detecting loads in at least two different directions is provided between the engagement point holder and the engagement point; 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 moments about an axis is mounted on the joint holder; the control calculation means is provided with a vibration excitation point position calculator for calculating the position of the excitation force point from the displacements of the plurality of vibration exciters, a vibration excitation point acceleration estimator for estimating the acceleration of the excitation force point from at least any one of the displacement, velocity and acceleration of the vibration exciters, and a reaction force calculation means for calculating the reaction force of the prototype from the acceleration estimated by the vibration excitation point acceleration estimator, the load detected by the load detector and the position of the excitation force point calculated by the vibration excitation point position calculator; and is equipped with at least one of an acceleration detector and an angular acceleration detector, and the control calculation means is equipped with 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 above-mentioned 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, there is provided a vibration exciting apparatus having at least three vibration exciters for causing vibration excitation of an object to be tested, a frame for mounting the vibration exciters, and at least two joints capable of structurally connecting the object to be tested to the vibration exciters, wherein the vibration exciters include 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; connecting a horizontal link and a vertical link to the horizontal vibration exciter and the vertical vibration exciter, respectively, and at least one horizontal link and at least one vertical link are connected to the joint; and the plurality of vibration exciters are configured so as to simultaneously impart a translational displacement and a rotational displacement to the object under test.

Furthermore, it is preferable that an engagement point holder for holding an 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; a vibration exciting point acceleration estimator for estimating an acceleration of an exciting force point from at least any one of a displacement, a velocity and an acceleration corresponding to the horizontal vibration exciter and the vertical vibration exciter, a vibration exciting point position calculator for calculating a position of the exciting 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 exciting force point calculated by the vibration exciting point position calculator, and the acceleration of the exciting force point estimated by the vibration exciting point acceleration estimator are provided; and 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 the excitation point based on a detection value of any of the above-mentioned 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.

Drawings

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.

Detailed Description

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 schematic view showing a vibration testing system for a structure. Fig. 2 shows an example of a vibration exciting apparatus used in the vibration testing system shown in fig. 1. Fig. 3 shows details of the load detector used in fig. 2. The vibration testing system according to the present invention uses full-scale or small-scale prototypes to perform vibration excitation testing on a portion of a structure under test and numerically model other portions of the structure, and performs vibration response calculations on the numerically modeled portions. 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, a joint 6 for transmitting a displacement of the vibration exciters to a prototype 14 mounted on a base 15, a load detector 12 provided from the prototype 14 to the vibration exciters 1, 2 and 3, and a control calculation device 100 which controls this multi-axis vibration excitation device 110 and has a digital calculator or an analog calculator for calculating a vibration response of a numerical model. The vibration exciters 1, 2 and 3 have cylindrical bodies 1b, 2b and 3b, drive shafts 1a, 2a and 3a, and displacement detectors 1c, 2c and 3 c.

The control computing device 100 has each of the following components. That is, there is provided a vibration exciting position calculating unit 101 for calculating the position of the exciting force point 16 located at the boundary portion between the numerical model and the prototype 14 based on the displacement of each of the vibration exciters 1, 2 and 3, a reaction force calculation unit 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 calculation unit 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 control unit 105 for operating the vibration exciters 1, 2 and 3 in accordance with the displacement command values to the vibration exciters 1, 2 and 3.

Incidentally, one of the features of the present invention is that an excitation force point capable of giving a rotational displacement and a translational displacement in its position is established. 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 the displacement and controlling the vibration exciters 1, 2 and 3, etc., it is preferable that it is a point on the surface of the apparatus. In this case, the excitation force point 16 can be provided on the junction point 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 the processing content of the computing apparatus 100 will be described based on the operational procedure.

(1) The prototype 14 is loaded with a displacement in the translational direction and the rotational direction using the multi-axis vibration excitation device 110, and the load detected by the load detector 12 is input to the control calculation device 100.

(2) The displacements of the vibration exciting machines 1, 2, and 3 related to the detected load are also input to the control calculation apparatus 100, and the vibration exciting point position calculation unit 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 calculation unit 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 clause (2).

(4) The vibration response calculation unit 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 clause (4) as the boundary portion between the prototype 14 and the numerical model, the vibration excitation point position calculation unit 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 item (5), the vibration exciter control unit 105 drives the vibration exciters 1, 2, and 3, and as a result, the prototype 14 is loaded with the displacement by the multi-axis vibration exciting device 110.

The above-described processes from (1) to (6) are repeated. Thus, even if 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 has a drive shaft side of a vibration exciter cylinder fixed to the side wall 4. This horizontal vibration exciter 1 has a joint 8 in the drive shaft. In this case, the arrangement of the horizontal vibration exciter 1 is such that the vibration exciter cylinder is not inserted into 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 vibration exciters cylinder is fixed to the top plate 5, and the cylinder of each vibration exciter is arranged so as not to enter into the reaction force frame. Furthermore, joint 6 is connected on the upper surface of prototype 14, and joint 7 is connected to prototype 14 through joint 6.

Although the joint 6 is formed in one plate shape in fig. 2, the shape, number and mounting position thereof are not limited thereto and can be appropriately provided as individually required. Furthermore, the joint 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, the degree of freedom, the number, and the mounting position thereof are not limited to the case of the joint 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-described 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 6 and the prototype-side joint 7 are provided as movable portions, 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 pipe for supplying oil to each vibration exciter moves in correspondence with the oscillation of the vibration exciter, the elastic force of the pipe acts as a disturbing action of the vibration excitation. On the other hand, in the present embodiment, since the vibration exciter cylinder is fixed to the reaction force frame, the pipe is not moved and exerts no 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 16. 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,

x_r＝x-d_zsinθ_y+bcosθ_y

z_r＝z-d_z(1-cosθ_y)+bsinθ_y

x₁＝x-d_zsinθ_y-bcosθ_y

z₁＝z-d_z(1-cosθ_y)-bsinθ_y(formula 2)

Wherein,

X，Z，θ_y: location of excitation force point

l₁: displacement of the horizontal vibration exciter 1

l₂: displacement of the vertical vibration exciter 2

l₃: displacement of the vertical vibration exciter 3

a₁: length of horizontal connecting rod

a₂: length of vertical connecting rod

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

d_z: height of the junction (see FIG. 4)

By using the above formula, the displacements of the vibration excitators 1, 2 and 3 can be uniquely calculated based on 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 uniquely determined based on the positions of the excitation force points according to the above-described method.

Then, a 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 prototype-side bonding points is two or more, thereby enabling the displacement of the vibration excitators to be uniquely 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 uniquely determined.

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_z

${\mathrm{\φ}}_y={\cos }^{-1}\frac{{4b}^2+{(x_r+b)}^2+{(a_2-l_3-z_r)}^2-{a_2}^2}{4b\sqrt{{(x_r+b)}^2+{(a_2-l_3-z_r)}^2}}$

${-\tan }^{-1}\frac{a_2-l_3-z_r}{x_r+b}$

(formula 3)

Wherein,

x_r＝b+a₁-l₁-a₁cosφ₁

z_r＝a₁sinφ₁

${\mathrm{\φ}}_1={\tan }^{-1}\frac{a_2-l_2}{a_1-l_1}-{\cos }^{-1}\frac{{a_1}^2+{(a_1-l_1)}^2+{(a_2-l_2)}^2-{a_2}^2}{{2a}_1\sqrt{{(a_1-l_1)}^2+{(a_2-l_2)}^2}}$

(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 system 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 exciter and the vertical vibration exciter 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 can be performed. In this case, insufficient results may be caused in view of the accuracy of the operation and the operation time. 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 6 shown in fig. 2. Load detectors 12a and 12b for detecting two orthogonal direction loads are arranged between the prototype-side joining point 6 and the joining point 7.

The method of calculating the reaction force at this time is as follows. Upon vibrational excitation, the joint 6, the prototype-side joint 7, and the load detectors 12a and 12b are excited simultaneously, so that an inertial force, a centrifugal force, and coriolis (coriolis's) force are generated in each device. When a force for rotating prototype 14 is applied, the overturning moment is generated in joint 6, prototype-side joint 7, and load detector 12 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.

$F_x=(f_{1x}+f_{2x})\cos {\mathrm{\θ}}_y-(f_{1r}+f_{2z})\sin {\mathrm{\θ}}_y$

$+m_t\stackrel{\·\·}{x}-m_t{h}_t\cos {\mathrm{\θ}}_y\·{\stackrel{\·\·}{\mathrm{\θ}}}_y+m_t{h}_t\sin {\mathrm{\θ}}_y\·{{\stackrel{\·}{\mathrm{\θ}}}_y}^2$

$F_z=(f_{1x}+f_{2x})\sin {\mathrm{\θ}}_y+(f_{1z}+f_{2z})\cos {\mathrm{\θ}}_y$

$+m_t\stackrel{\·\·}{z}-m_t{h}_t\sin {\mathrm{\θ}}_y\·{\stackrel{\·\·}{\mathrm{\θ}}}_y-m_t{h}_t\sin {\mathrm{\θ}}_y\·{{\stackrel{\·}{\mathrm{\θ}}}_y}^2+m_{t}g$

$M_y=(f_{1z}-f_{2z})b-(f_{1x}+f_{2x})d_z$

$+(I_t+m_t{h_t}^2){\stackrel{\·\·}{\mathrm{\θ}}}_y-m_t{h}_t\cos {\mathrm{\θ}}_y\·\stackrel{\·\·}{x}-m_t{h}_t\sin {\mathrm{\θ}}_y\·\stackrel{\·\·}{z}-m_{t}g{h}_t\sin {\mathrm{\θ}}_y$

(formula 5)

Wherein,

F_x，F_z，M_y: reaction forces generated in the prototype

f_1x，f_1z，f_2x，f_2z: load detected by load detector

Acceleration of excitation point

m_t: total mass of joint and load detector

I_t: moment of inertia about the global centre of gravity of the joint and the load detector

h_t: height from lower surface of joint to overall gravity center of 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 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, in addition to the load detected in the load detector 12, values of the inertial force, the centrifugal force, the coriolis force, and the overturning moment acting on the joint point 6, the joint point 7, and the load detector 12 are necessary. 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 apparatus 100, there are provided a vibration excitation point velocity estimation unit 106a for estimating the velocity at the excitation force point 16 based on the displacement, velocity, and acceleration of the vibration exciter, and a vibration excitation point acceleration estimation unit 106b for estimating the acceleration. In the reaction force calculation unit 102, the 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 calculation unit 101, the velocity of the excitation force point estimated by the vibration excitation point velocity estimation unit 106a, and the acceleration estimated by the vibration excitation point acceleration estimation unit 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 estimation unit 106a and the vibration excitation point acceleration estimation unit 106b, for example, the position of the excitation force point obtained based on the displacement of the vibration exciter is differentiated, and the velocity and acceleration of the excitation force point are estimated from the displacement, velocity, and acceleration of the vibration exciter using the observer. According to the present embodiment, since the velocity can be estimated by the vibration excitation point velocity estimation unit 106a and the acceleration can be estimated by the vibration excitation point acceleration estimation unit 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 of the present invention will be described 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 6 so as to obtain the excitation force point velocity and acceleration. Using the outputs of the acceleration detector 13a and the angular velocity detector 13b, the velocity and acceleration of the excitation force point can be calculated with high accuracy. In this case, the acceleration detector 13a and the angular velocity detector 13b may be separate bodies or may be integrated. Also, the angular velocity can be calculated based on the detection value of the acceleration detector 13 a. Further, 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 simple manner.

The vibration excitation point velocity and acceleration calculation unit 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 calculation unit 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 calculation unit 101, and the velocity and acceleration of the excitation force point 16 calculated by the vibration excitation point velocity and acceleration calculation unit 107, and calculates the reaction force according to equation 5. In this case, for example, in the vibration excitation point velocity and acceleration calculation unit 107, the acceleration and angular velocity detected by the acceleration detector 13a and the angular velocity detector 13b 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 joint 6, and the unit 107 for calculating the velocity and the acceleration of the excitation force point based on the detected acceleration and the 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 system according to the present invention will be described below. Between the joint 6 and the prototype 14, there is provided 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. Details of the joint 6 are shown in figure 8. In the present embodiment thus configured, the reaction force can be calculated based on equation 6.

F_x＝f_xcosθ_y-f_zsinθ_y

F_z＝f_xsinθ_y+f_zcosθ_y

M_y＝m_y(formula 6)

Wherein,

f_x，f_z，m_y: 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 system 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 test system having a compact size and high rigidity.

The present invention can be embodied in various other forms without departing from the spirit or essential characteristics thereof. Accordingly, the preferred embodiments described herein are presented by way of example only, and not by way of limitation. 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 (12)

1. A vibration testing apparatus for a structure, the apparatus being provided with vibration exciting means for causing 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 vibration testing apparatus thereby performing vibration testing of the entire structure,

wherein the vibration exciting device is provided with a plurality of vibration exciters for causing the prototype to vibrate and excite; a plurality of displacement detectors for detecting displacements of the plurality of vibration actuators and a load detector for detecting a load applied to the prototype, and

the control calculation device is equipped with a calculator that calculates displacements of a predetermined excitation force point in the translational direction and the rotational direction based on the load detected by the load detector and the displacements of the vibration exciter detected by the plurality of displacement detectors, and a signal generator that outputs a drive signal corresponding to the calculated displacements of the excitation force point in the translational direction and the rotational direction to the vibration exciter to generate a displacement in the calculated translational direction and the rotational direction of the excitation force point.

2. A vibration testing apparatus for a structure, which is equipped with vibration exciting means for causing vibration excitation to a prototype imitating a part of the structure and control calculating means 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 the vibration exciting apparatus is equipped with the plurality of vibration exciters, and the plurality of vibration exciters are configured such that a translational displacement and a rotational displacement are simultaneously applied to a point where the vibration exciters are installed.

3. A vibration testing apparatus for a structure according to claim 2, wherein the vibration exciting apparatus has at least three of the 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 the vibration exciters and the prototype.

4. A vibration testing apparatus for a structure according to claim 3, wherein horizontal links are connected to the horizontal vibration exciters and vertical links are connected to the vertical vibration exciters, 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 according to claim 3, wherein a joint holder for fixing the joint to the 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 the joint.

6. A vibration testing apparatus for a structure according to 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 mounted to the joint holder.

7. A vibration testing apparatus for a structure according to claim 3, wherein said control calculating means is equipped with a vibration exciting point position calculator for calculating exciting force point positions from displacements of said plurality of vibration exciters; a vibration excitation point acceleration estimator for estimating the excitation force point acceleration from at least any one of a displacement, a velocity, and an acceleration of the vibration exciter; and reaction force calculation means for calculating a reaction force of the prototype based on the acceleration estimated by the vibration excitation point acceleration estimator, the load detected by the load detector, and the position of the excitation force point calculated by the vibration excitation point position calculator.

8. A vibration testing apparatus for a structure according to claim 3, wherein at least one of an acceleration detector and an angular acceleration detector is provided, and said control calculating means is provided with a vibration exciting point velocity and acceleration calculator for calculating an acceleration of the exciting force point based on a detection value of any of said 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.

9. A vibration exciting apparatus having at least three vibration exciters for causing vibration excitation of an object to be tested, a frame for mounting the vibration exciters, and at least two joints capable of structurally connecting the object to be tested to the vibration exciters, wherein the vibration exciters include 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; connecting a horizontal link and a vertical link to the horizontal vibration exciter and the vertical vibration exciter, respectively, and at least one horizontal link and at least one vertical link are connected to the joint; and the plurality of vibration exciters are configured so as to simultaneously impart a translational displacement and a rotational displacement to the object under test.

10. A vibration exciting device according to claim 9, 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.

11. The vibration excitation device according to claim 9, wherein a vibration excitation point acceleration estimator for estimating an acceleration of an excitation force point from at least any one of a displacement, a velocity, and an acceleration corresponding to the horizontal vibration exciter and the vertical vibration exciter is provided; a vibration exciting point position calculator for calculating an exciting force point position from displacements of the horizontal vibration exciter and the vertical vibration exciter, and a reaction force calculator for calculating a reaction force from the object under test based on the load detected by the load detector, the exciting force point position calculated by the vibration exciting point position calculator, and the acceleration of the exciting force point estimated by the vibration exciting point acceleration estimator.

12. The vibration exciting apparatus according to claim 9, wherein at least any one of an acceleration detector and an angular acceleration detector is provided; a vibration excitation point velocity and acceleration calculator for calculating the acceleration of the excitation force point based on the detection value of any one 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.