JPH03110437A - Load testing device - Google Patents

Abstract

PURPOSE:To measure a load applied to a testing body in the axial direction and shearing direction by providing a guiding device of table motion applying the load to the testing body and an arithmetic device of command value applying to an exciter. CONSTITUTION:The testing body 1 is fixed to a jig 2 and the table 3. When a pressure is applied by the exciter 6, the table motion according to a deformation is made along a rod 93 by a static pressure bearing 91b of the guiding device 9. When a tension is applied by an exciter 5, the table motion is made along a rod 92 by a static pressure bearing 91a. At this time, the upper surface 1a of testing body 1 is maintained in the horizontal position by a moment M0. Each exciter is incorporated with a load detector 7 detecting the loaded amount and a displacing amount detector 8 respectively, and inclined angles to table coordinates of each exciter are calculated from a length between joints and the displaced amount at the processing center of each exciter, then the objective loads applied to the testing body 1 in the axial direction and shearing direction are converted to components in the axial direction of each exciter according to he inclined direction to issue commands to each of them. With this constitution, a rotational motion of the testing body 1 is restrained, thereby the object load can be accurately measured while keeping the upper end horizontal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a load testing device suitable for material testing and fatigue testing of seismic isolation elements and various structures for protecting building structures from earthquakes.

[Conventional technology]

The conventional device is described, for example, in Mitsubishi Heavy Industries Technical Report Vol. 23, No. 3 (19
87-5), a pressure plate that applies axial and shear loads to the specimen is supported by a horizontally movable summer parallelogram ring, and the axial deformation and shear direction of the specimen are The mechanism was designed to simultaneously allow deformation and maintain the horizontality of the end surface of the specimen. Furthermore, the Transactions of the Japan Society of Mechanical Engineers ((Jl) Vol. 54, No. 507 (Sho 63-11)
) P.

The test piece described in No. 2618 applies force to two specimens at the same time, and has a mechanism that allows simultaneous loading in the axial and shear directions while maintaining the horizontality of the end face of the specimen using a link-type jig.

Note that related devices of this type include, for example, Japanese Patent Application Laid-Open No. 62-24124.

[Problem to be solved by the invention]

All of the above-mentioned conventional technologies use a link mechanism to maintain the horizontality of the end surface of the test specimen and load it in the axial direction and shear direction, but there are structural limitations in increasing the rigidity of the link. When the amount of deformation of the test specimen in the shear direction becomes large, the bending moment at the upper and lower ends of the test specimen makes it impossible to keep the end surfaces horizontal, resulting in a problem in which the accuracy of the loading test decreases.

The present invention has been made in order to solve the problems of the prior art described above, and restrains the rotational movement of the end face due to the bending moment at the upper and lower ends of the specimen, which is caused by the large amount of deformation of the specimen in the shear direction. The object of the present invention is to provide a loading test device that can apply targeted loads in the axial direction and shear direction to the test specimen regardless of the state of the vibrator.

Another object of the present invention is to provide a loading test device that can measure the loads in the axial direction and shear direction that are applied to a test specimen no matter what state the vibrator is in.

[Means to solve the problem]

The above purpose is to hold the table that applies axial and shear loads to the test specimen using static pressure bearings to restrain rotational movement, and to equip each vibrator with a guide device that allows movement in two orthogonal directions. This is achieved by providing a command value calculation device that calculates the required load amount as a function of the length of the joint at the stroke center of each vibrator, the amount of displacement, the target axial load, and the target shear direction load.

The other purpose is to calculate the force actually applied to the test specimen in two directions using the length of the joint at the stroke center of each vibrator, the amount of displacement, and the load of each vibrator in the same configuration as above. This is achieved by providing a state quantity calculation device that calculates the load detected by the detector as a function.

[Effect]

According to the above technical means, the rotational movement of the end face due to the bending moment at the upper and lower ends of the test piece, which occurs due to the large amount of deformation in the shear direction of the test piece, is restrained by the static pressure bearing of the guide device, and each The command load to be applied to the vibrator is determined by determining the inclination angle of each vibrator with respect to the table coordinates based on the length of the joint at the stroke center of each vibrator and the amount of displacement from the stroke center, and then determining the command load to be applied to the test specimen in the target axial direction. and is determined by converting the load in the shear direction into an axial component of each vibrator using this inclination angle.

In addition, according to the other technical means mentioned above, the axial and shear loads applied to the test specimen are determined by the inclination angle of each vibrator with respect to the table coordinates, which is determined in the same manner as described above. It is determined by converting the load detected by a load detector into table coordinates.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.

First, FIG. 1 is an overall structural diagram of a loading test apparatus according to an embodiment of the present invention, and FIG. 2 is an overall control system diagram of the apparatus shown in FIG. 1. Items with the same symbols each time are the same parts.

In FIG. 1, reference numeral 1 denotes a seismic isolation element which is a test specimen, and its lower end face is attached to a mounting jig 2, and its upper end is attached to a table 3 with a large number of bolts. The table 3 is connected via a swivel joint 4a to an X-axis vibrator 5 that applies a load in the shear direction to the specimen 1 and a Y-axis vibrator 6 that similarly applies a load in the axial direction. There is. Each vibrator includes a load detector 7 for detecting the amount of load and a displacement detector 8 for detecting the amount of displacement, and is connected to the reaction wall 16 via a swivel joint 4b.

The guide device 9 that guides the table 3 in two orthogonal directions is
It is composed of a static pressure bearing 91a that supports the table 3, an X-axis guide rod 92 that guides it in the shear direction, and a Y-axis guide rod 93 that supports the entire table 3 with a static pressure bearing 91b and guides it in the axial direction.

In addition, 10 in FIG. 2 is a signal generator that generates a voltage signal corresponding to the target load, 11 is a command value calculation device whose details will be described later, 13 is an adder, and 14 is a servo amplifier.
Reference numeral 15 is constituted by a state quantity calculation device whose details will be described later.

FIG. 3 is a diagram showing the definition of the coordinate system of the apparatus shown in FIG. 1, and shows the X-axis vibrator 5. Both Y-axis vibrators 6 have their stroke centers as zero points, and the pistons of the vibrators have + and - references. In addition, the center-to-center length of the swivel joint at the stroke center of each vibrator (hereinafter abbreviated as length between joints) is Lx.

The amount of displacement from the zero point is detected by the displacement detector 8 as xo and yo. At this time, the loading amount of each vibrator is f
The load detector 7 detects it as x and fy.

Figure 4 shows the shear direction load W on the test specimen, the seismic isolation element 1.
Showing the deformation state when x and axial load wy are applied,
At this time, in order to keep the upper end surface 1a and lower end surface 1b of the seismic isolation element 1 parallel, it is necessary to maintain a moment MO expressed by the following formula on the mechanical device side.

M o =-(Wx-H+Wy-XI)-
(1) Here, Wx: Shear load Wy: Axial load H: Test specimen height FIG. 5 shows the content of the calculation process of the command value calculation device 11 and state quantity calculation device 15 shown in FIG. 2 in a flowchart. It is something. The command value calculation device 11 calculates the displacement amount XO,y of the vibration exciter.
The angles θx and Oy that the vibration exciter forms with each axis are calculated using this and the joint lengths Lx and Ly input in advance, and from this, the target shear direction load Px given by the signal generator 10 and the axis The directional load py is converted into load values Fx and Fy in the axial direction of the vibrator, which are used as command signals to the servo system. In addition, the state quantity calculation device 15 converts the loads fx and fy detected by the load detector 7 into load values in the X-axis and Y-axis directions using the angles θX and θy obtained in the same manner as described above, and calculates the shear load. Determine W x and axial load wy.

Next, the operation will be explained.

First, in FIG. 1, when the Y-axis vibrator 6 applies force to the pushing side, it is transmitted to the test specimen 1 via the swivel joint 4a, the hydrostatic bearing 91a, and the table 3. At this time, the movement of the table due to the amount of deformation in the Y-axis direction is the guide device i! It is supported by the static pressure bearing 91b of 9 and extends along the Y-axis guide rod 93. next.

When the X-axis vibrator 5 applies a tensile force, the swivel joint 4
a and the table 3 to the test specimen 1. The movement of the table due to the amount of deformation in the X-axis direction at this time is supported by the static pressure bearing 91a and follows the X-axis guide rod 92. At this time, the deformation state of test specimen 1 is expressed as shown in Fig. 4, and the moment MO expressed by equation (1) is fixed to the static pressure bearing 91b that supports the X-axis guide rod and the reaction wall 1b. The upper end surface 1a of the specimen 1 is held horizontally by the Y-axis guide rod 93.

Further, as shown in FIG. 3, each vibration exciter has an angle Ox with respect to the X axis and the Y axis, respectively, depending on the position of the table 3.

The shear load Wx and the axial load wy that form Oy and are applied to the test specimen 1 do not match the loading amounts fx and fy of each vibrator detected by the load detector 7.

The force balance relationship is expressed by the following equation.

Wy=-f x 0sirl x+f x ′cos
a y Furthermore, the position of the table 3 can be found using the following equation.

X=Lx (Lx-xo) (Lx-Lex Lx'Lex2-
(Lx”+Ly2) (Lex2-Ly2))Lxz+L
y” Lx−0 Y=Ly (3) Here, 2・(Lx−xo) Lx2+Ly2 1 (5) Equation (2) is rewritten as follows.

Therefore, Load command value Fx given to the vibrator.

y teeth, Formula (6) It can be found by the following formula by inversely transforming.

As shown in Fig. 5, the command value calculation device 1 1 is Vibration Machine displacement xo.

yo and joint length Lx.

Equations (4) and (5) are calculated from Ly, and the load value converted using Equation (7) according to the target shear load Px and target axial load py is output as a command value to the vibrator.

The state quantity calculating device 15 similarly takes in the outputs fx and fy of the load detector 7, and outputs the load value converted by equation (6) as the load applied to the test specimen 1.

According to the loading test device of this example, the rotational movement of the upper end of the test specimen due to the moment that increases with the deformation of the test specimen in the shear direction is restrained by the guide device using a hydrostatic pressure bearing system, and the position of the table is adjusted to The angle that the vibrator makes with the X and Y axes is calculated from the displacement amount of the vibrator and the length of the joint, and the target load to be applied to the test specimen is applied by converting the axis of the vibrator, which improves accuracy. Good loading tests are now possible, and the effects are significant.

In addition, the state quantity calculation device similarly converts the load measured by the load detector attached to each vibrator to the coordinate system of the specimen and outputs it, thereby calculating the shear direction applied to the specimen. And the load in the axial direction can be measured with high accuracy.

Therefore, by using both in combination, the effect can be even greater.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to simultaneously tolerate axial deformation and shear direction deformation of a test specimen in a test in which loads are applied to the test specimen in the axial direction and shear direction, and to prevent rotational motion. The upper end of the specimen can be restrained horizontally, and the target load can be applied accurately no matter what state the vibrator is in in each direction. Since it is also possible to monitor the load, highly accurate loading tests are possible.

[Brief explanation of drawings]

FIG. 1 is a structural diagram showing the overall configuration of a loading test device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the control system of the device shown in FIG. 1, and FIG. 3 is a diagram similar to the one shown in FIG. Figure 4 is a diagram that defines the coordinate system of the device shown in Figure 4 is a diagram that explains the force applied to the test specimen and the deformation state, and Figure 5 is a diagram that explains the calculation processing of the command value calculation device and state quantity calculation device of the present invention. It is a flow diagram showing the contents. 1... Test specimen, 3... Table, 4a, 4b...
Swivel joint, 5...X-axis vibrator, 6...Y
Axial vibrator, 7... Load detector, 8... Displacement detector,
9 River guide design, 91a, 91b...static pressure bearing, 11.
・・Command value calculation unit 4th cause■ Figure／／

Claims (1)

[Claims] 1. A table on which a test specimen is loaded, a two-axis vibrator that applies force in two directions to the test specimen via this table, and a rotary motion that guides the table in two orthogonal directions. A loading test device consists of a guide device that restrains the specimen, a load detector that detects the force of the vibrator, and a displacement detector that detects the amount of displacement of the vibrator. The amount of load that should be applied to each of the above vibrators is calculated as a function of the joint length at the stroke center of each vibrator, the amount of displacement of each vibrator, the target shear load, and the target axial load. 1. A load testing device comprising: a command value calculation device; and a control circuit configured to input each load amount resulting from the calculation to the two-axis vibration exciter as a command load signal. 2. In the device described in claim 1, the forces in two directions actually applied to the test specimen are calculated by measuring the length of the joint at the stroke center of each vibrator, the displacement of each vibrator, and the force in two directions actually applied to the test specimen. A loading device characterized in that a state quantity calculation device is provided to calculate the load amount detected by the load detector as a function, and a control circuit is configured to output the shear load and axial load as measurement signals as the calculation results. Test equipment.