JPH09184598A - Vibrationproof tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent vibrational response in water contact from being increased by supporting a hollow shell body on which small holes through which liquid can be allowed to flow to or out are provided to the front surface to a horizontal tank inner structural material through elastic bodies such as vibrationproof rubber. SOLUTION: A square hollow shell body 8 in which small holes 9 through which liquid can be allowed to flow in and out is provided on the front surface is supported to a horizontal tank inner structural material 3 through elastic bodies 7 such as vibrationproof rubber. When liquid is stored in a main tank, liquid is allowed to flow into the hollow shell body 8 through the small holes 9 provided on the front surface of the hollow shell body 8, and the inside of the hollow shell body 8 is filled with liquid. Therefore, vibrational response can be prevented from being increased without any extension of a falling stopping elbow plate 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration tank such as an oil tanker ship.

[0002]

2. Description of the Related Art A tank of an oil tanker is shown in a horizontal sectional view in FIG.
As shown in FIG. 1, it is composed of an outer plate 1, a tank inner partition wall 2, and a horizontal tank inner structure 3. Outer plate 1 and tank inner partition 2
A stiffener 4 is provided on the tank, and a stiffener 5 and an anti-tilt elbow plate 6 are also provided on the tank structure member 3.

[0003] Here, the tumbling natural circular frequency of the in-tank structural member 3 is generally sufficiently high when there is empty water and there is no problem.
It may exist in the vibration frequency range of the propulsion device of a ship, and the horizontal tank structure member 3 may exhibit a resonance phenomenon to damage the tank. For this reason, it is necessary to devise a method for separating the lateral tilt natural circular frequency of the horizontal tank structure member 3 from the frequency range of the vibration force of the propulsion device of the ship, and a typical example of the conventional method is shown in FIG. As described above, it is possible to increase the rigidity by increasing the fall prevention elbow plate 6 to increase the natural circular frequency of the same structural material.

[0004]

However, such a conventional method requires a large number of the tilt-preventing elbow plates 6 in comparison with the tilt-preventing elbow plates 6 originally required from the viewpoint of preventing the sideways falling. In addition, the weight of the tank is increased and the workability is deteriorated. The present invention has been proposed in view of such circumstances, and does not require an additional fall prevention elbow plate 6,
It is an object of the present invention to provide a tank capable of preventing an increase in vibration response during contact with water.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the structure of the present invention is a tank comprising an outer plate, a tank inner partition wall, and a horizontal tank internal structural member. It is characterized in that it supports a hollow shell body in which small holes capable of inflowing and outflowing of liquid are appropriately provided on the surface through an elastic body such as rubber.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG. 1. Reference numeral 1 is an outer plate, 3 is a horizontal tank internal structural member, and the horizontal tank internal structural member 3 is a liquid tank. A rectangular hollow shell 8 having a small hole 9 capable of inflow and outflow on the surface thereof was supported via an elastic body 7 such as a vibration-proof rubber. In the figure, 5 is a stiffener, and 6 is an anti-tilt elbow plate.

2 and 3 show another embodiment, in which the hollow shell 8 is formed in a cylindrical shape. Here, the elastic body 7 may be a coil spring, a sponge or the like in addition to the vibration-proof rubber, and is sealed so as not to come into direct contact with the liquid stored in the tank, if necessary. As a feature of the tank of the present invention, since the hollow shell body has a hollow structure, a lightweight structure can be achieved, and thus the required rigidity of the elastic body 7 can be small.

When the liquid is stored in this tank, the liquid also flows into the inside of the hollow shell 8 through the small holes 9 provided on the surface of the hollow shell 8, and the inside of the hollow shell 8 is filled with the liquid. Charged by. At this time, the rigidity K of the elastic body 7 is used as a spring element, and the liquid inside the hollow shell body 8 is used as a mass element M 1.
A vibration system with a degree of freedom is formed. The natural circular frequency ω ₀ of this vibration system is given by the equation (1).

[0009]

[Equation 1] However, K: rigidity of the elastic member _{7 M = M W + M S} + M A ... (2) M W: mass of the hollow shell 8 inside the liquid M _S: mass M _A of the hollow shell 8: hollow shell 8 external Mass of additional liquid of Eq. (1) so that the natural circular frequency of the horizontal tank internal structural member 3 becomes equal to the natural circular frequency of the lateral vibration of the tank, the size of the hollow shell 8 and the number of elastic bodies 7 Is determined.

Now, considering a case where the horizontal tilt natural circular frequency of the horizontal tank structure member 3 resonates, the exciting force F in this case and the horizontal tilt direction of the horizontal tank structure member 3, that is, the vertical up and down direction. As for the relationship of the vibration displacement y in the direction, as shown in FIGS. 4A and 4B, the phase of the vibration displacement y lags the exciting force F by 90 °. Next, the vibration displacement x of the hollow shell body 8 induced by the vibration displacement of the horizontal tank structure member 3 also resonates in the vibration system formed by the hollow shell body 8 as described above.
As shown in (c), the phase is further delayed by 90 ° with respect to the vibration displacement y of the horizontal tank structure member 3. At this time, the hollow shell 8
Assuming that the inertial force generated at F _I is F _I , this reaction force F _C acts on the horizontal tank internal structural member 3.

Where F_I= M ・ (d^Twox / dt^Two) F_C= -F_I (3) From formula (3), F_C= -F_I= -M (d^Twox / dt^Two) = Mω^Twox (4) However, ω: Lateral tilting natural circular vibration of the structural member 3 in the horizontal direction
Number, that is, from the formula (4), the acting force is as shown in FIG.
F_CAnd the vibration displacement x of the hollow shell 8 are in the same phase. Above
In summary, the acting force F as shown in FIG._CIs the excitation force F and
It will be in the opposite phase. Therefore, acting force F_CCancels the exciting force F
Effective vibration force F + F _CIs the actual vibration
It becomes smaller than the force F.

For this reason, the vibration response of the horizontal tank structure member 3 can be made smaller than that in the case without the hollow shell 8. Such an effect of the present invention is schematically shown in FIG. 5 in comparison with the effect of the conventional method. In the figure, broken line 1
Reference numeral 0 is a curve representing the vibration acceleration of the structural material in the horizontal tank of the unmeasured structure, the one-dot chain line 11 corresponds to the conventional countermeasure structure in which the fall prevention elbow plate 6 is added, and the solid line 12 corresponds to the tank of the present invention. In the conventional countermeasure structure, a large number of fall prevention elbow plates 6 are required to increase the natural circular frequency, and there is a possibility that the new natural circular frequency resonates with another vibration force.

On the other hand, in the tank of the present invention, its vibration response can be suppressed as a whole, and there is no fear of resonance phenomenon with another vibration force, which is also effective in this respect.

[0014]

As described above, according to the present invention, a hollow shell body provided with a small hole through which liquid can flow in and out is appropriately provided in a horizontal tank structure material by an elastic body such as a vibration-proof rubber. Since it is supported through the hollow shell, the horizontal shell can suppress the lateral vibration response of the structural material inside the tank in the horizontal direction, so it is simpler and more reliable than the conventional method. This has the effect of preventing damage from occurring due to the resonance phenomenon of the material.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of the present invention.

FIG. 2 is a plan view showing another embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a diagram illustrating the operation of the present invention.

FIG. 5 is a diagram comparing the effect of the present invention with a conventional method.

FIG. 6 is a plan view showing a conventional example.

FIG. 7 is a front view showing a conventional example.

[Explanation of symbols]

 3 Horizontal tank construction material 7 Elastic body 8 Hollow shell body 9 Small hole

Claims (1)

[Claims] 1. A tank comprising an outer plate, a tank inner partition wall, and a horizontal tank internal structure member, in which liquid can flow into and out of the horizontal tank internal structure member through an elastic body such as a vibration-proof rubber. An anti-vibration tank, which supports a hollow shell body having various small holes appropriately provided on the surface.