JPH0457972B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is an excitation device suitable for use in measuring unsteady aerodynamic force in an aeroelastic test, which applies vertical vibration (Heaving) and rotation to a test specimen. The present invention relates to a two-degree-of-freedom vibration excitation device that performs vibration in a pitching vibration mode.

[Prior art]

Conventionally, in aeroelasticity tests for bridges and the like, an excitation device that vibrates the test specimen is used to measure the unsteady aerodynamic force generated. This type of vibration excitation device is configured to apply vertical vibrations and rotational vibrations about a horizontal axis to a test specimen. Specifically, the axial center position of the side surface of the specimen is supported, and vertical vibration is applied by vertically moving this support part. In addition, rotational vibrations are generated by installing a horizontal rod on the extension line of the horizontal axis of the test specimen, providing a lever on this rod, giving the lever reciprocating up and down motion, and causing the horizontal rod to reciprocate and rotate. There is.

However, in the conventional vibration excitation device, the vertical vibration mechanism and the rotational vibration mechanism are provided independently, and the vertical vibration and rotational vibration are generated separately. For this reason, conventional vibration devices are only capable of vibration with one degree of freedom, and cannot provide coupled vibration that combines vertical vibration and rotational vibration, making it impossible to conduct tests that correspond to actual conditions. There was a problem.

[Purpose of the invention]

An object of the present invention is to provide a two-degree-of-freedom vibration excitation device that can apply vertical vibration and rotational vibration to a test specimen independently, and can also apply coupled vibration in two-degree-of-freedom modes.

[Structure of the invention]

In order to achieve the above object, a two-degree-of-freedom vibration excitation device according to the present invention includes a vertically vibrating rod whose movement is restricted in the vertical direction and a rotationally movable rod arranged parallel to the vertically movable rod. One end of the vibration rod is directly or indirectly connected to the specimen at an arbitrary axial center position of the test specimen, and one end of the rotary vibration rod is connected to the specimen at a side position, and the other ends of both rods are connected to each other. a driving means connected to the connecting plate to form a parallel link mechanism and providing reciprocating motion in the vertical direction to the vertical vibration rod connecting point of the connecting plate; and a driving means for imparting rotational motion.

Due to the vertical configuration, when vertical vibration is to be generated, vertical reciprocating motion can be applied only to the vertical vibration rod connection point of the connecting plate by the driving means, and when rotational vibration is to be generated, the connecting plate is placed in a fixed position. By applying reciprocating rotational movement to the connecting plate around the connecting point of the vertical vibration rod, rotational movement is applied by the parallel link mechanism. On the other hand, in coupled vibration, by operating both drive means at the same time, the coupling plate itself is rotated reciprocally within the movement system of the coupling plate that is moved up and down, so that coupled vibration can be achieved with two degrees of freedom: vertical and rotational vibration. It can be given to the test specimen.

[Embodiments of the invention]

Hereinafter, specific embodiments of the two-degree-of-freedom vibration excitation device according to the present invention will be described in detail with reference to the drawings.

The drawing is an overall perspective view showing the configuration of the vibration device according to the present embodiment. As shown in the figure, the vibration device supports the test specimen 10 at both end portions thereof, and includes a vertical vibration rod 12 and a vertical vibration rod 12.
A pair of rotary vibration rods 14 are arranged parallel to each other. The vertical vibration rod 12 is arranged vertically, and is regulated by a guide (not shown) so that its movement direction is vertical. This vertical vibration rod 12 has its upper end connected to the axial center of the test object 10, and is indirectly connected to the test object 10. That is, a support shaft 16 is attached to both end faces of the test specimen 10 at an arbitrarily determined axis position (centroid, center of gravity, etc.), and a support member 18 equipped with an aerodynamic force measurement sensor is attached to the support shaft 16. is installed. The vertical vibration rod 12 is indirectly connected to the shaft center via a support member 18. On the other hand, the rotary vibration rod 14 is formed to have the same length as the vertical vibration rod 12 and is arranged in parallel on both sides thereof.
is connected to. Each connection point is positioned symmetrically with respect to the connection point of the vertical vibration rod 12. Further, both rods 12 and 14 are connected to the test specimen 10 and extend vertically downward, and their lower ends are connected to each other via a connecting plate 20, respectively. The connecting positions of the rods 12 and 14 with respect to the connecting plate 20 are symmetrical with respect to the connecting point of the vertically vibrating rod 12, and are in the same relational position as the connecting state of the upper ends of the rods with the support member 18. Both rods 1 arranged in parallel in this way
2 and 14 form a parallel link mechanism, and a connecting plate 20
The vertical movement and rotational movement of the supporting member 18, that is, the vertical movement and rotational movement of the test specimen 10, have a one-to-one correspondence.

Further, a driving means for applying vertical vibration and a driving means for applying rotational vibration are connected to the first half connecting plate 20 in series.

First, the drive means for applying vertical vibration has a link 24 that is pin-coupled to the connecting point 22 of the vertical vibration rod 12 on the connecting plate 20, and extends downward on the extension line of the vertical vibration rod 12. ing. This link 24 is connected to the left and right connecting plates 20.
The lower ends of both links 24 are pivotally connected to a lever 26. The lever 26 is provided on a rotating shaft 28 that is arranged at the bottom of the apparatus in parallel with the support shaft 16 on the test specimen 10 side, and projects from both ends in a state perpendicular to the axis of the lever, and is connected to the link 24. connected. The rotating shaft 28 is supported by a bearing (not shown), and by being reciprocated in a fixed position, it can transmit reciprocating vertical motion to the link 24 via the lever 26. Further, the rotating shaft 28 is integrally provided with an arm 30 that is perpendicular to its axis, and one end of a connecting rod 32 is pivotally attached to the tip of the arm 30. The other end of the rod 32 is connected to a crank 38 provided at the tip of a drive shaft 36 rotated by a motor 34.
Therefore, the rotary shaft 28 is reciprocated by the motor 34 via the drive shaft 36, the crank 38, the connecting rod 32, and the arm 30, and the lever 2
6. The connecting plate 20 is moved up and down via the link 24, and the test specimen 10 is vibrated up and down. The amount of vertical displacement of the test object 10 can be set arbitrarily by changing the crank 38, and the frequency of vibration can be set arbitrarily by changing the rotation speed of the motor 34.

On the other hand, the driving means for applying rotational vibration is formed as follows. Vertical/rotational vibration rod 1
A link 40 is connected to both ends of the connecting plate 20 connecting the parts 2 and 14 with a pin, and the lower end of the pair of links 40 is attached to a donut-shaped rotating disk 4.
It is connected to 2. The connection position with respect to the rotating disk 42 is set at a position 180 degrees opposite to the rotation center thereof, and by making the connection position similar to the connection position of the connection plate 20, a parallel link mechanism is provided to the pair of links 40. It is being formed. In addition, the rotating disk 42
A pair of levers 46 are further connected to the levers 46 . This lever 46 is connected at a position 180 degrees opposite to the line orthogonal to the line connecting the connection points of the links 40, and extends in the opposite direction to the lever 26 for vertical vibration. This lever 46 is further connected to arms 50 at both ends of another rotating shaft 48 arranged parallel to the rotating shaft 28 for vertical vibration. The rotating shaft 48 is supported by a bearing (not shown) and is capable of reciprocating rotation. Further, the arm 50 is integrated with the rotating shaft 48 and extends in the diametrical direction thereof, and the pair of levers 46 are connected to the tip end thereof. The pair of levers 46 also form a parallel link mechanism, and the rotary disk 42 is reciprocated by the reciprocating rotation movement of the rotary shaft 48, causing the pair of links 40 connected thereto to move in the vertical direction in opposite phases. I try to make them do this. As a result, the connecting plate 2
0 performs reciprocating rotational motion around the connection point 22 of the vertical vibration rod 12, making it possible to impart rotational vibration to the test specimen 10. Further, in order to reciprocate the rotary shaft 48, one arm 50 is formed to be extended, and a connecting rod 52 is pivotally attached to the extended end. The connecting rod 52 connects to the vertical vibration motor 3.
The drive shaft 56 is connected to a crank 58 at the tip of a drive shaft 56 that is rotated by a motor 54 provided separately from the drive shaft 56 . Therefore, the motor 54 applies reciprocating rotational motion to the rotating shaft 48 via the drive shaft 56, crank 58, connecting rod 52, and arm 50, thereby causing the test specimen 10 to rotate about the support shaft 16. It can give vibrations. The amount of rotational displacement of the test specimen 10 can be arbitrarily set by changing the crank 58, and the frequency can be arbitrarily set by changing the rotation speed of the motor 54.

A detector 60 for detecting vertical displacement is provided at the mounting position of the vertical vibration rod 12, and a detector 62 for detecting rotational displacement is provided on the shaft end side of the rotating shaft 48. Further, detectors 64 and 66 for detecting the vertical vibration frequency and rotational frequency are installed so as to detect the reciprocating rotational frequency of each drive shaft 36 and 56. Furthermore, 68 in the figure is a balance weight attached to the support shaft 16 portion.

With the vibration excitation device configured as described above, when exciting the test specimen 10, it is not only possible to perform vertical vibration and rotational vibration independently, but also to perform coupled vibration that combines both vibrations. Become. That is, the rotation of the motor 34 is caused by the reciprocating rotation of the rotary shaft 28 by a mechanism involving the crank 38, and this rotates the connecting plate 2.
By causing the vertical vibration rod 12 to reciprocate in the vertical direction via the vertical axis 0, vertical vibration is applied to the test specimen 10. On the other hand, the rotation of the motor 54 is caused by the reciprocating rotation of the drive shaft 48 by a mechanism including a crank 58, which is connected to the pair of rising links 40.
make a vertical movement with opposite phase. This vertical movement causes the connecting plate 20 to reciprocate and rotate around its center (the connecting point 22 of the vertical vibration rods), and the test specimen 10 is moved through a pair of rods 14 forming a parallel link mechanism.
This excites rotational vibration. Therefore,
Each vibration can be performed independently.

Furthermore, both of the above-mentioned vibrations involve the connection plate 20, and since the rotational vibration is a reciprocating rotational movement centered on the connection point 22 of the vertical vibration rod 12, the motion coordinate system for vertical vibration is It is possible to perform rotational vibration using the same method, and coupled vibration can be reliably achieved. In particular, in this embodiment, the rotary disk 42 is simultaneously vibrated vertically when vibrating vertically, but since the disk 42 and the rotary shaft 48 are connected by a parallel link mechanism including a lever 46, the rotary shaft 48 itself It does not need to be placed inside the vertical vibration system. As a result, the drive sources for vertical and rotational excitation can be fixedly installed. Therefore, there is no need to install a rotary vibration means including a drive source for rotational vibration in the vertical vibration system, so it is possible to reduce the size of the device and eliminate vibration factors other than vertical and rotational vibrations.
This has the advantage of being able to perform two-degree-of-freedom excitation with certainty and precision.

In the above embodiment, the test specimen 10 and the vertical and rotational vibration rods 12 and 14 were indirectly connected.
It may also be directly connected to the end face of the test specimen 10. Further, although the rod 14 and the link 40 for rotational vibration are each composed of a pair of members, it is sufficient as long as motion transmission is possible, and it is also possible to use only one member.

〔Effect of the invention〕

As explained above, the two-degree-of-freedom vibration excitation device according to this embodiment has the excellent effect of being able to vibrate the test specimen not only with vertical and rotational vibrations but also as coupled vibrations.

[Brief explanation of the drawing]

The drawing is a perspective view showing the overall configuration of a two-degree-of-freedom vibration excitation device according to this embodiment. 10...Test specimen, 12...Vertical vibration rod,
14... Rotating vibration rod, 20... Connection plate, 2
2... Rod connection point for vertical vibration, 24, 40...
Link, 28, 48... Rotating shaft, 38, 5
8...Crank, 34, 54...Motor.

Claims (1)

[Claims] 1. It has a vertical vibration rod whose movement is restricted in the vertical direction and a rotational vibration rod arranged parallel to said rod, and one end of said vertical vibration rod can be placed at any axial center position of the test specimen and said rotation one end of the vibrating rod is connected directly or indirectly to the test specimen at its side position, and the other ends of the two rods are mutually connected to a connecting plate to form a parallel link mechanism;
It is characterized by comprising: a drive means for giving a reciprocating motion in the vertical direction to a rod connection point for vertical vibration of the connecting plate; and a drive means for giving a reciprocating rotational movement to the connection plate about the rod connection point for vertical vibration. 2
Degree of freedom vibration device.