JP2002068085A - Hull construction receiving vibration control stay of propulsion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hull construction having the rigidity sufficient for exercising the effect of the vibration control stay, and not generating the bending moment having the bad influence on the hull vibration. SOLUTION: A basic part 21 of the vibration control stay 2 is pivoted at one gunwale side of a predetermined position of an upper part of a propulsion engine 1, a deck 4 of a predetermined height is mounted on the ship body structure formed by a shell plating 5 and a trans web 6, and both gunwales of the propulsion engine 1, the vibration control stay 2 having the predetermined length and the rigidity is horizontally mounted, an inclined member 9 is mounted from a tip part 22 of the vibration control stay 2 toward the intersection of the shell plating 5 and the deck 4, and further a vertical member 10 linked with the tip part 22 of the vibration control stay 2 and an inner end part of the deck 4 is mounted to form a triangle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hull structure for receiving a vibration damping stay of a main engine used for reducing lateral vibration of a main engine of a ship and hull vibrations caused by the vibration.

[0002]

2. Description of the Related Art Conventionally, a hull structure for receiving an anti-vibration stay 2 of a main engine 1, as shown in FIG. 2, is necessarily provided on a hull side corresponding to a mounting position of the anti-vibration stay 2 of the main engine 1 on the main engine side. Since there is not always a hull structural member, a method of providing a pillar 7 between the deck 4 and the double bottom 3 to receive an anti-vibration stay as shown in FIG. 2 (a) or a method as shown in FIG. 2 (b) A method of providing a bracket 8 on the adjacent deck 4 and receiving the anti-vibration stay 2 has been adopted.

Here, the role of the anti-vibration stay of the main engine will be briefly described.
If the resonance point of the horizontal vibration of the main engine such as shape vibration is expected to generate large vibrations in the normal rotation speed range of the main engine, the natural frequency of these vibrations will be increased by connecting the main engine and the hull with stays Then, the resonance point is driven out of the normal rotation speed range to avoid resonance.

[0004] The principle that the lateral vibration natural frequency of the main engine is increased by the vibration isolation stay will be described using a simple vibration model. The lateral vibration system of the main engine in the actual structure as shown in FIG. 3A can be replaced with a simple vibration model as shown in FIG. 3B if the main engine 1 is assumed to be a rigid body. Here, the symbol m is the mass of the main engine, kd, ks, and kh are the rotational rigidity of the main engine stand with respect to the lateral displacement of the main engine, the lateral rigidity of the anti-vibration stay, and the lateral rigidity of the hull structure, respectively. In this model, the mass m, that is, the natural frequency of the transverse vibration of the main engine, is expressed by the following formula (1), where w is the natural frequency without the vibration-isolating stay, and W is the natural frequency with the vibration-isolating stay. ) And (2), and when there is an anti-vibration stay, the natural frequency increases by (ks * kh) / (ks + kh) in equation (2) compared to the case where there is no anti-vibration stay.

(Equation 1)

[0005]

As described in the description of the prior art, the natural frequency of lateral vibration of the main engine is increased by the vibration isolating stay, and the amount of the increase is the rigidity ks of the vibration isolating stay and the hull receiving it. It depends on both the rigidity kh of the structure and the amount of increase in the natural frequency changes depending on the rigidity kh of the hull structure.

For example, as shown in FIG. 2A, when the anti-vibration stay 2 of the main engine 1 is removed from the pillar 7, the rigidity k of the hull structure is increased.
Since h is determined by the bending rigidity of the pillar 7, when the stay height is far from the deck height, it is difficult to obtain high rigidity even by using a relatively large pillar, and as a result, a sufficient intrinsic In many cases, an increase in frequency cannot be expected. Also, as shown in FIG. 2 (b), a method of providing the bracket 8 on the deck 4 and receiving the anti-vibration stay 2 is sufficient because the hull rigidity kh is determined by the bending and shear rigidity of the bracket 8. It is difficult to obtain rigidity. Furthermore, these hull structures generate a bending moment M on the hull by the load transmitted from the main engine through the vibration isolating stay 2 as shown in FIGS. In some cases, cracks 11 and 12 were generated in the hull structure and pillars.

[0007] The present invention has been made in view of such insufficient points of the prior art, and has as its object the purpose of having sufficient rigidity to exhibit the effect of an anti-vibration stay. Another object of the present invention is to provide a hull structure that does not generate a bending moment that adversely affects hull vibration.

[0008]

According to the present invention, a base 21 of an anti-vibration stay 2 is pivotally mounted on one side of a predetermined position on an upper portion of a main engine 1, and the outer plate 5 is connected to a transformer. A deck 4 is provided at a certain height on both sides of the hull structure constituted by the web 6 and the main engine 1, a rigid anti-vibration stay 2 having a predetermined length and rigidity is provided horizontally, Of the anti-vibration stay 2 and the deck 4 are provided with a slanting member 9 from the tip 22 of the anti-vibration stay 2 to the intersection of the outer plate 5 and the deck 4.
Has a vertical member 10 linked to the inner end of the triangle, and constitutes a triangle.

A base 21 of an anti-vibration stay 2 is pivotally mounted at a predetermined position on one side of the upper part of the main engine 1, and a hull structure composed of an outer plate 5 and a transformer web 6 is provided on both sides of the main engine 1. A height of the deck 4 is provided, a vibration-proof stay 2 having a predetermined length and rigidity is provided horizontally, and a horizontal member 13 is provided from a tip end portion 22 of the vibration-proof stay 2 toward the outer plate 5. The vertical member 10 is linked to the distal end 21 of the anti-vibration stay 2 and the inner end of the deck 4 to form a square.

[0010]

In the embodiment shown in FIG. 1 (a), an inclined member 9 made of H-shaped steel or the like is connected to a tip end 2 of a vibration isolating stay 2 of a main engine 1.
2 is arranged obliquely toward the intersection of the outer panel 5 and the deck 4, and its end is fixed to the hull structure. In addition, the main engine side is linked with the vertical member 10 such as H-shaped steel dropped from the deck 4,
The anti-vibration stay 2 is linked to the intersection of the vertical member 10 and the inclined member 9.

In the embodiment shown in FIG. 1B, a horizontal member 13 made of H-section steel or the like is attached to the vibration isolating stay of the main engine 1.
2 is arranged horizontally from the front end portion 22 to the outer plate, and the end portion is fixed to the trans web 6 of the outer plate, and the main engine side is linked to the vertical member 10 similarly lowered from the deck 4,
The anti-vibration stay 2 is linked to the intersection of the vertical member 10 and the horizontal member 13.

[0012]

Since the present invention is configured as described above, the following effects can be obtained.

In the embodiment shown in FIG. 1A, since the inclined member 9, the deck 4, and the vertical member 10 form a triangular truss structure, a bending moment is hardly generated in each member, and the hull side is not provided. The vibration of the deck does not occur even if the main engine vibration is transmitted. In addition, since the stiffness of the hull is dominated by the tensile rigidity of the inclined member 9, the rigidity can be secured if the cross-sectional area of the inclined member 9 is large enough, and the effect of the vibration isolating stay can be sufficiently exhibited.

FIG. 5 is a graph showing the vibration of the main engine left and right when the anti-vibration stay is attached and when the anti-vibration stay is removed in an actual ship in which the anti-vibration stay is attached to the hull structure using the embodiment shown in FIG. It is a comparison of acceleration, but when the anti-vibration stay is removed, the large resonance peak that occurred at the normal rotation speed rises out of the operating speed range with the anti-vibration stay attached. The response changes to a low value, which proves that the hull structure according to the present invention is effective as a hull structure subjected to vibration isolating stays.

On the other hand, although the truss structure is not formed in the embodiment shown in FIG. 1B, the transweb 6 of the outer plate to which the horizontal member 13 is fixed is bent as compared with the pillar 7 and the bracket 8 shown in FIG. Since the rigidity is high, an effect similar to the above is exerted.

Further, since the hull structure according to the present invention can be formed by a frame structure using H-section steel or the like, the inclined member 9 can be formed.
In addition, piping, ventilation space, and the like can be secured between the horizontal member 13 and the hull deck 4, and there is no hindrance to the engine room outfitting.

In addition, since the structure is simple, even when a new anti-vibration stay is provided on an existing ship, the construction can be easily performed.

[Brief description of the drawings]

FIG. 1 schematically shows an embodiment of the present invention in a sectional view.

FIG. 2 shows a conventional hull structure for receiving a vibration isolating stay of a main engine,
It is schematically shown in a sectional view.

FIG. 3 shows a lateral vibration of a main engine using a simple vibration model.

FIG. 4 is a cross-sectional view showing an example of a hull deformation when a transverse vibration of a main engine is transmitted to a hull through a vibration-isolating stay in a conventional hull structure receiving a vibration-isolating stay of a main engine.

FIG. 5 is a graph showing the effect of the embodiment by actually measured values of an actual ship.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main engine 2 Anti-vibration stay 3 Double bottom 4 Deck 6 Transweb 7 Pillar 9 Inclined member 10 Horizontal member 13 Vertical member

Claims (2)

[Claims] A base of an anti-vibration stay is pivotally attached to a predetermined position on one side of the upper part of the main engine, and a hull structure composed of an outer plate and a transweb is provided at a fixed height on both sides of the main engine. A deck is provided, a vibration-proof stay having a predetermined length and rigidity is provided horizontally, and a tilting member is provided from a tip end of the vibration-proof stay toward an intersection of an outer plate and a deck, and a vibration-proof stay is provided. A hull structure for receiving an anti-vibration stay of a main engine, having a vertical member linked to a front end portion and an inner end portion of a deck, and having a triangular configuration. 2. A base of an anti-vibration stay is pivotally mounted on one side of the main engine at a predetermined position on one side, and a hull structure composed of an outer plate and a transweb is provided at a fixed height on both sides of the main engine. A deck is provided, a vibration-proof stay having a predetermined length and rigidity is provided horizontally, and a horizontal member is provided from the tip of the vibration-proof stay toward the outer plate, and the tip of the vibration-proof stay and the deck are provided. A hull structure for receiving an anti-vibration stay of a main engine, wherein the hull structure has a vertical member linked to an inner end thereof and forms a quadrangle.