JP2023158896A - Centrifugal load tester - Google Patents

Abstract

To provide a centrifugal load tester which can give prescribed vibration acceleration to a sample by suppressing vibration of a support frame without increasing the weight of the recessed support frame that supports an excitor that excites in the direction in parallel to a surface of a table on which the sample is placed and an excitor that excites in the vertical direction.SOLUTION: A recessed support frame 13 includes a recess 21 which is located on the center and protrusions 22 which are located on both sides of the recess 21. A Z direction excitor 14 is installed on a bottom surface 21a of the recess 21 of the support frame 13 and an X direction excitor 15 is installed in the protrusion 22 of the support frame 13. The Z direction excitor 14 and the protrusion 22 of the support frame 13 are connected with each other by a connection member 19.SELECTED DRAWING: Figure 2

Description

The present invention relates to a centrifugal loading test device that performs tests by simultaneously applying centrifugal acceleration and vibration acceleration to a specimen such as a scale model of the ground, and in particular applies vibration acceleration in a direction parallel to the surface of a table on which the specimen is mounted. This invention relates to a centrifugal loading test device that applies loads in two directions: and a perpendicular direction.

For example, when a scale model of the ground is created and a test related to a gravitational field is performed, a load simulating gravity is applied to the specimen by applying centrifugal acceleration in order to reproduce the stress caused by gravity. In addition, earthquake vibration acceleration is applied to the specimen in order to reproduce the shaking of the ground caused by an earthquake.

A centrifugal loading test device that simultaneously applies centrifugal acceleration and vibrational acceleration to a specimen is equipped with a vibration table that is equipped with a table that applies vibrational acceleration and an exciter on a swinging pedestal that is supported by a pin fulcrum of a rotating arm. . Then, by placing the specimen on a table and rotating the rotary arm at high speed, centrifugal acceleration can be applied to the specimen, and by vibrating the table, vibrational acceleration can be applied to the specimen.

In order to reproduce the shaking caused by an earthquake in detail, it is necessary to apply vibration acceleration to the specimen in two directions: horizontal and vertical. An example of a structure of a vibration table that can apply vibration acceleration in the horizontal and vertical directions is disclosed in Patent Document 1.

In the device described in Patent Document 1, the structure of the vibration table includes a concave support pedestal, a vibrator having one end fixed to the support pedestal, and a vibration table connected to these vibrators via bearings. (table). The vibrating table can be vibrated in the horizontal and vertical directions by vibrating machines placed on the left, right, and below sides of the vibrating table.

Japanese Patent Application Publication No. 2018-115914

In the structure of the vibration table as described in Patent Document 1, if the rigidity of the concave support pedestal supporting the vibrator is insufficient, the vibration (resonance) of the support pedestal causes the excitation force of the vibrator to be transferred to the vibration table table. The problem is that the information is not sufficiently communicated to the public. In this case, a predetermined vibration performance (vibration acceleration) of the vibration table cannot be obtained.

In particular, the side wall portion (convex portion) of the concave support frame has a cantilever-like structure with the bottom surface of the centrally located concave portion serving as a fixed end. For this reason, when a horizontal vibrator fixed to the side wall is used to vibrate the vibration table, a large amount of vibration occurs due to horizontal tilting of the side wall (cantilever bending) in the concave support pedestal, causing problems. It can be.

In order to solve such problems, it is common practice to increase the thickness of the support pedestal or add rigid reinforcing members such as ribs to compensate for the lack of rigidity of the support pedestal. However, if such a method of increasing rigidity is applied to a centrifugal loading test device, the weight of the swinging frame increases and the centrifugal force acting on the rotating arm increases. Therefore, it becomes necessary to increase the rigidity of the entire centrifugal loading test apparatus, such as the rotating arm, and the weight of the entire centrifugal loading test apparatus increases.

An object of the present invention is to avoid increasing the weight of a concave support frame that supports a vibrator that vibrates in a direction parallel to the surface of a table on which a specimen is mounted and a vibrator that vibrates in a direction perpendicular to the surface of the table on which the specimen is mounted. It is an object of the present invention to provide a centrifugal loading test device that can suppress the vibration of the support frame and apply a predetermined vibration acceleration to the specimen.

In order to solve the above problems, the centrifugal loading test device of the present invention has a rotating shaft arranged in the vertical direction, a rotating arm fixed to the rotating shaft, and a pin fulcrum provided on the rotating arm that can swing. and a rotation drive device that drives the rotating shaft, the direction along the central axis of the pin fulcrum being the Y direction, passing through the center of gravity of the rocking pedestal, and the central axis of the pin fulcrum. When the direction along a straight line orthogonal to the Z direction is defined as the Z direction, and the direction perpendicular to the Y direction and the Z direction is defined as the The supporting frame includes a mount, a table on which a specimen is mounted, an X-direction vibrator that vibrates the table in the X direction, and a Z-direction vibrator that vibrates the table in the Z direction. , a recess located in the center and a protrusion located on both sides of the recess, the Z-direction vibrator is installed on the bottom surface of the recess of the support pedestal, and the protrusion of the support pedestal The X-direction vibration exciter is installed in the X-direction vibration exciter, and the Z-direction vibration vibration machine and the convex portion of the support frame are connected by a connection member.

According to the present invention, there is no need to increase the weight of the concave support pedestal that supports the vibrator that vibrates in a direction parallel to the surface of the table on which the specimen is mounted and the vibrator that vibrates in the perpendicular direction. It is possible to provide a centrifugal loading test device that can suppress the vibration of the support frame and apply a predetermined vibration acceleration to the specimen.

FIG. 1 is a longitudinal cross-sectional view of a centrifugal loading test apparatus according to a first embodiment of the present invention. FIG. 1 is a longitudinal cross-sectional view of the swing frame according to the first embodiment of the present invention. FIG. 2 is a top view of the swinging pedestal according to the first embodiment of the present invention. FIG. 6 is a diagram schematically showing vibration deformation when the table is vibrated in the X direction when there is no connecting member according to the first embodiment of the present invention. FIG. 7 is a longitudinal cross-sectional view of a swing frame according to a second embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. The following description shows one embodiment of the present invention, and the present invention is not limited to this embodiment.

《First embodiment》
FIG. 1 shows the configuration of a centrifugal loading test apparatus according to a first embodiment of the present invention.
As shown in FIG. 1, the basic configuration of a centrifugal loading test device for applying centrifugal acceleration is a rotating shaft 1, a rotating arm 3, swing frames 5a and 5b, a rotating drive device 6, and a rotating shaft. It includes an upper support member 7 and a rotating shaft lower support member 8.

The rotating shaft 1 is arranged in the vertical direction. The rotating arm 3 is fixed to the rotating shaft 1. Specifically, the rotating arm 3 extends horizontally from the rotating shaft 1 and rotates together with the rotating shaft 1 around the central axis 2 of the rotating shaft 1. The swing frames 5a and 5b are swingably supported and suspended from a pin fulcrum 4 provided on the rotating arm 3. Rotary drive device 6 drives rotary shaft 1 . The rotating shaft upper support member 7 and the rotating shaft lower supporting member 8 support the rotating shaft 1 via a bearing (not shown).

The rotating shaft 1 has an upper part supported by a building upper floor 9a via a rotating shaft upper support member 7, a lower part supported by a building lower floor 9b via a rotating shaft lower support member 8, and a lower end that is rotatably driven. It is connected to device 6. The rotating arm 3 includes a center frame 3a fixed to the rotating shaft 1, a side frame 3b extending horizontally from the center frame 3a, and an end frame 3c provided at the tip side of the side frame 3b.

The swing frames 5a and 5b are arranged at symmetrical positions with respect to the rotation axis 1, and are suspended in the vertical direction when the rotating arm 3 is stopped, as shown by the solid line in FIG. On the other hand, when the rotary arm 3 rotates under the driving force of the rotary drive device 6, the swing frames 5a and 5b swing up to a horizontal state as shown by the dotted line in FIG. 1 due to the centrifugal force caused by the rotation. . The specimen 10 is mounted on a table 11 installed on a swing frame 5a. A balance weight (not shown) is mounted on the swing frame 5b so that the centrifugal force acting on the swing frame 5b is the same as that on the swing frame 5a. By adjusting the weight and center of gravity position of the swing frame 5b in this manner, unbalanced rotational vibrations during rotation of the centrifugal loading test apparatus are suppressed.

FIG. 2 shows the detailed structure of the swing frame 5a on which the specimen 10 is mounted.
For convenience of explanation, the direction along the central axis 41 of the pin fulcrum 4 is referred to as the Y direction, and the direction along the straight line passing through the center of gravity of the swing frame 5a (not shown) and orthogonal to the central axis 41 of the pin fulcrum 4 is referred to as the Z direction. The direction perpendicular to this direction and the Z direction is defined as the X direction. Here, the X direction is an in-plane direction of the flat table 11 on which the specimen 10 is mounted, and the Z direction is an out-of-plane direction of the table 11.

As shown in FIG. 2, the swinging pedestal 5a includes a side plate 12, a support pedestal 13, a table 11, an X-direction vibrator 15, and a Z-direction vibrator 14. The side plate 12 is swingably supported by a pin fulcrum 4 provided on the rotating arm 3. At the end of the side plate 12 opposite to the pin fulcrum 4, a concave support pedestal 13 with a concave center when viewed in a cross section parallel to the XZ plane is installed. A specimen 10 is mounted on the table 11. The X-direction vibrator 15 vibrates the table 11 in the X direction, and the Z-direction vibrator 14 vibrates the table 11 in the Z direction.

The support frame 13 has a recess 21 (a depressed concave portion) located at the center and convex portions 22 located on both sides of the recess 21 . A Z-direction vibrator 14 is installed on the bottom surface 21a of the concave portion 21 of the support pedestal 13, and an X-direction vibrator 15 is installed on the top surface 22a of the convex portion 22 of the support pedestal 13. The Z-direction vibration exciter 14 is connected to a table via a Z-piston 14a movable in the Z-direction, a flat Z base 16, an X-linear guide rail 17a arranged in the X-direction, and an X-linear guide block 17b movable in the X-direction. 11. The X-direction vibrator 15 is connected to the table 11 via an X-piston 15a movable in the X-direction, a Z-linear guide block 18b movable in the Z-direction, and a Z-linear guide rail 18a arranged in the Z-direction.

Further, the side surface 14 b of the Z-direction vibrator 14 and the inner surface 22 b of the convex portion 22 of the support pedestal 13 are connected by a connecting member 19 . The connecting member 19 is here joined to the Z-direction vibrator 14 and the convex portion 22 of the support frame 13 by welding, but is not limited to this, and may be joined by, for example, screw fastening. The shape of the connecting member 19 is a rectangular parallelepiped here, but it may also be a cylinder, a hollow circular tube, a square tube, or the like. As the material of the connecting member 19, for example, metal such as steel is used.

FIG. 3 shows a view of the swing frame 5a viewed from above (XY plane). To simplify the display, FIG. 3 shows only the table 11, side plate 12, support pedestal 13, Z-direction vibrator 14, X-direction vibrator 15, and connection member 19 among the members shown in FIG. .

As shown in FIG. 3, in this embodiment, an example is given in which four Z-direction vibration exciters 14 and four X-direction vibration exciters 15 are arranged. A pair of side plates 12 are provided, and the pair of side plates 12 are respectively attached so as to sandwich both end surfaces of the support frame 13 in the Y direction. The connecting member 19 that connects the Z-direction vibrator 14 and the convex portion 22 of the support frame 13 is arranged perpendicularly to the surface of the convex portion 22 that faces the Z-direction vibrator 14, that is, the inner surface 22b. There is.

When the table 11 is vibrated in the Z direction, the Z piston 14a is moved in the Z direction by the Z direction vibrator 14, and the Z base 16, X linear guide 17, table 11, and Z linear guide rail 18a are integrated and vibrated in the Z direction. do. When the table 11 is vibrated in the X direction, the X piston 15a is moved in the X direction by the X direction vibrator 15, and the Z linear guide 18, table 11, and X linear guide block 17b are integrally vibrated in the X direction. In this way, the support frame 13 has a concave structure with a concave center, and the Z-direction vibration exciter 14 is installed below the table 11 (when not in operation), and the X-direction vibration exciter 15 is installed on the side of the table (when it is not in operation). Placed. Thereby, vibration acceleration can be generated in a direction parallel to and perpendicular to the surface of the table 11.

In FIG. 2, only the outer shape of the structure of the support frame 13 is shown, but weight reduction is achieved by forming a honeycomb structure in which plate members are assembled by welding or the like. In this embodiment, an example is described in which four Z-direction vibration exciters 14 and four X-direction vibration exciters 15 are arranged, but the number of each vibration exciter 14 and 15 is limited to this. isn't it. Furthermore, the X linear guide 17 and the Z linear guide 18 may be arranged so that the rails and blocks are interchanged.

Vibration acceleration is generated in the table 11 by the driving force of the vibrators 14 and 15, and at this time, the support pedestal 13 vibrates in response to the reaction force of the driving force of the vibrators 14 and 15. When the support pedestal 13 strongly vibrates (resonates), the driving force of the vibrators 14 and 15 and the vibration of the support pedestal 13 on which the vibrators 14 and 15 are mounted may be out of phase by 180 degrees. In such a case, the driving force of the vibrators 14 and 15 is not sufficiently transmitted to the table 11, or the excitation driving force cannot be sufficiently controlled, making it impossible to generate a predetermined vibration acceleration on the table 11. Sometimes.

FIG. 4 shows the vibration deformation when the table 11 is vibrated in the X direction when there is no connecting member 19 installed between the side surface 14b of the Z direction vibrator 14 and the inner surface 22b of the convex portion 22 of the support frame 13. It is a figure shown typically. If the concave support pedestal 13 does not have the connecting member 19, vibration deformation of the support pedestal 13 and the vibrators 14 and 15 as shown in FIG. 4 will occur when the table 11 is vibrated in the X direction, which may pose a problem. Sometimes. In the modification shown in FIG. 4, the convex portion 22 of the support pedestal 13 and the X-direction vibrator 15 installed on the top surface 22a thereof fall down in the X direction, and the vibrator 15 installed on the bottom surface 21a of the concave portion 21 of the support pedestal 13 The Z-direction vibrator 14 is tilted in the X-direction. Furthermore, the X-direction vibrator 15 (and convex portion 22) and the Z-direction vibrator 14 are tilted in opposite directions (in FIG. (to the left in the paper), that is, they vibrate in opposite phases.

The deformation shown in FIG. 4 is caused by the deformation of the support pedestal 13 in the X direction, particularly by the cantilever bending deformation of the convex portion 22 of the concave support pedestal 13 that has a cantilever shape. In order to suppress this deformation, generally, a structure is adopted that increases the rigidity of the protrusion 22 of the support pedestal 13, such as by increasing the thickness of the protrusion 22 of the support pedestal 13, or by adding a rib member. Changes will be considered. However, increasing the thickness of the support pedestal 13 or adding rib members increases the weight of the support pedestal 13, that is, the weight of the swinging pedestal 5a, which is difficult to adopt from the viewpoint of increasing the weight of the device. In view of the above-mentioned problems, the present invention has a structure that suppresses vibrations caused by deformation of the support pedestal 13 shown in FIG. That is.

In the present embodiment described above, as shown in FIGS. 2 and 3, the concave support pedestal 13 has a concave portion 21 located at the center and convex portions 22 located on both sides of the concave portion 21. A Z-direction vibration exciter 14 is installed on the bottom surface 21a of the recess 21 of the support pedestal 13, and an X-direction vibration exciter 15 is installed on the protrusion 22 of the support pedestal 13. The Z-direction vibrator 14 and the convex portion 22 of the support frame 13 are connected by a connecting member 19. Thereby, the vibrations of the Z-direction vibrator 14 and the convex portion 22 (inner surface 22b) of the support pedestal 13, which are vibrating in opposite phases as described in FIG. 4, can be canceled out, thereby suppressing the vibrations of both.
Therefore, according to the present embodiment, the vibration of the support pedestal 13 can be reduced by simply adding the connecting member 19 without increasing the weight of the concave support pedestal 13 that supports the X-direction vibrator 15 and the Z-direction vibrator 14. It is possible to provide a centrifugal loading test device that can suppress the vibration and apply a predetermined vibration acceleration to the specimen 10.

If the rigidity of the connecting member 19 is too low, it will be difficult to transmit and cancel each other's vibrations, so the connecting member 19 should have a certain level of rigidity, such as at least the same level as the convex part 22 of the Z-direction vibrator 14 or the support frame 13. It is preferable.

It is preferable that the connecting member 19 connects the entire connectable surface in the Z direction between the Z-direction vibrator 14 and the inner surface 22b of the convex portion 22. However, as shown in FIG. You may connect only the upper part. Even with this configuration, a sufficient vibration suppression effect can be obtained. In this case, since it is not necessary to install the connecting member 19 from the bottom surface 21a of the recess 21 of the support frame 13, the connecting member 19 can be made smaller and lighter.

Further, in this embodiment, the connecting member 19 is arranged perpendicularly to the inner surface 22b of the convex portion 22, which is the surface facing the Z-direction vibrator 14. With this configuration, deformation of the support frame 13 in the X direction can be more effectively suppressed. However, the connecting member 19 may be arranged at an angle with respect to the inner surface 22b. Furthermore, in FIGS. 2 and 3, one Z-direction vibrator 14 and the inner surface 22b of the convex portion 22 are connected by one connecting member 19, but they are connected by a plurality of connecting members 19. It's okay.

《Second embodiment》
FIG. 5 shows a vertical cross-sectional view of a swing frame according to a second embodiment of the present invention.
The second embodiment is based on a structure in which a plurality of Z-direction vibration exciters 14 (two in FIG. 5) are installed in the X direction. In the second embodiment, the structure and arrangement of each member in the swing frame, such as the support frame 13, the X-direction vibration exciter 15, and the Z-direction vibration exciter 14, are the same as in the first embodiment (see FIG. 2). It is.

In the second embodiment, in addition to the connecting member 19 that connects the Z-direction vibrator 14 and the convex portion 22 of the support frame 13 in the first embodiment, the Z-direction vibrator 14 arranged in the X direction It has another connecting member 19a that connects the. The rigidity, connection area, and number required for the connection member 19a are the same as those for the connection member 19 described in the first embodiment.

In this way, in the second embodiment, the Z-direction vibration exciter 14 and the convex portion 22 of the support frame 13 are connected by the connecting member 19, and the Z-direction vibration exciters 14 are connected to each other by another connecting member 19a. connected. With such a configuration, it is possible to obtain the effect of canceling out the vibrations of the Z-direction vibrator 14 and the convex portion 22 (inner surface 22b) of the support frame 13, which are vibrating in opposite phases as described in the first embodiment. . In addition to this, the bending rigidity of the convex portion 22 of the support frame 13 is improved by connecting the inner surfaces 22b of the opposing convex portions 22 via the Z-direction vibrator 14 and the connecting members 19, 19a. Therefore, it is possible to obtain a greater vibration suppression effect than in the first embodiment. In other words, according to the second embodiment, the concave support pedestal 13 that supports the X-direction vibrator 15 and the Z-direction vibrator 14 can be supported by simply adding the connecting members 19 and 19a, without increasing the weight of the concave support frame 13. It is possible to provide a centrifugal loading test apparatus that can suppress the vibration of the gantry 13 and apply a predetermined vibration acceleration to the specimen 10.

In FIG. 5, the connecting member 19a connects the Z-direction vibration exciters 14 arranged in the X direction. With this configuration, vibration of the support frame 13 in the X direction can be suppressed more effectively. However, the connecting member 19a may connect any two of the plurality of Z-direction vibration exciters 14.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the embodiments described above are described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to add, delete, or replace some of the configurations of the embodiments described above with other configurations.

1 Rotating shaft 3 Rotating arm 4 Pin fulcrum 5a Swing frame 6 Rotation drive device 10 Specimen 11 Table 41 Center axis 13 Support frame 14 Z-direction vibrator 14b Side surface 15 X-direction vibrator 19 Connecting member 19a Connecting member 21 Recess 21a Bottom surface 22 Convex portion 22a Top surface 22b Inner surface

Claims (3)

A rotation axis arranged vertically,
a rotating arm fixed to the rotating shaft;
a swinging pedestal that is swingably supported by a pin fulcrum provided on the rotating arm;
A rotational drive device that drives the rotational shaft,
The direction along the central axis of the pin fulcrum is the Y direction, the direction along the straight line passing through the center of gravity of the swing frame and perpendicular to the central axis of the pin fulcrum is the Z direction, and the direction perpendicular to the Y direction and the Z direction. When is the X direction,
The swinging frame is
a concave support pedestal with a concave center when viewed in cross section parallel to the X-Z plane;
a table on which the specimen is mounted;
an X-direction vibrator that vibrates the table in the X-direction;
a Z-direction vibrator that vibrates the table in the Z-direction;
The support frame has a recess located at the center and protrusions located on both sides of the recess,
The Z-direction vibration exciter is installed on the bottom surface of the recess of the support pedestal,
The X-direction vibrator is installed on the convex portion of the support frame,
A centrifugal loading test device, wherein the Z-direction vibrator and the convex portion of the support frame are connected by a connecting member. A plurality of the Z-direction vibration exciters are provided,
The centrifugal loading test apparatus according to claim 1, wherein the Z-direction vibration exciters are connected to each other by another connecting member. The centrifugal loading test apparatus according to claim 1, wherein the connecting member is arranged perpendicularly to a surface of the convex portion facing the Z-direction vibrator.

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