JP3392565B2 - Hull skin structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hull skin structure.

[0002]

2. Description of the Related Art Conventionally, as shown in the perspective view of FIG. 2, a plurality of longitudinal stringers 10 which are parallel to each other intersect with a plurality of parallel transverse girders 11 at regular intervals so as to cross each other. It is supported and formed by a lattice-like structure. Here, stringer 1
The cross section of 0 is either the T-shaped cross section with face 20 shown in FIG. 3 or the faceless strip 22 shown in FIG. 4, but in either case the strip 22 is spanned between the spans of the cross beam 11. The cross-sectional shape is constant.

[0003]

By the way, when an out-of-plane pressure acts on the outer plate 13, the bending moment M received by one stringer 10 is, as shown in FIG. Has a catenary-shaped curve, and this waveform is regularly repeated for each span. Therefore, in the conventional outer plate structure, the cross-sectional shape of the stringer 10 is determined by satisfying the structural strength permissible condition at the cross girder support position where the bending moment is maximum, and excludes both ends between spans. In the position cross section, a slight margin (luxury) in structural strength is left. That is, as the optimum stringer 10, the cross-sectional shape is changed in the longitudinal direction so as to exactly match the allowable condition at a plurality of points or lines, so that the outer plate structure can be reduced in weight. When the cross-sectional shape of the stringer 10 is a T-shaped cross section with the face 20 shown in FIG. 3, the face 20 is joined by fillet welding compared to the case of the strip plate cross section shown in FIG. However, the total welding length increases. This may increase the number of man-hours required for welding work. Therefore, if all the structural strength requirements including buckling within the range of the strip cross section can be satisfied, the longitudinal strip method using the strip cross section can be used. Can be said to be more economical.

The present invention has been proposed in view of the above circumstances, and an object thereof is to provide a lightweight and economical hull skin structure.

[0005]

To this end, the invention according to claim 1 provides a plurality of long parallel stringers each having a rectangular cross section in an upright posture that extends in the vertical direction in parallel at a set span in the horizontal direction, Ru <br/> grid name and a plurality of parallel cross beams of T-shaped cross section extending in the phase transmural manner fitted to parallel to the transverse direction from each other through the respective slots each stringer at vertical setting span In a hull skin structure in which the lower end of the structure on the same horizontal plane is fixed to the upper surface of a horizontal skin, each stringer is set to the maximum height at the cross girder support position, and the girder is supported at the longitudinal span center. The upper end curve of the deformed W shape that has the maximum value of the height lower than the height at the position and also has the minimum value at the two positions slightly closer to the center from both ends of the same span has the upper end height changing smoothly. Characterized by having a stringer

The invention according to claim 2 is the variant according to claim 1, which has a minimum value at a position separated by 15% to 25% of the longitudinal span length from the cross girder supporting position of the stringer. It is characterized by having a W-shaped upper end line.

[0007]

According to such a structure, the upper end line of the stringer is not parallel to the lower end line, and the shape between the spans is a modified W-shape. Therefore, the side surface in the span is not a vertically long rectangular shape, but a modified rectangular shape having an inscribed W-shaped upper end line inscribed therein, which is lighter than the conventional stringer with considerably less bulkiness.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the present invention will be described. FIG. 1 is a side view showing a part of the stringer.

In the above drawing, the same reference numerals as those in FIGS. 2 to 5 indicate the same members as those in the same drawings, and where the structure of the present invention differs from that of FIG. 2, the height of the stringer is flat. Variant W
It is formed so as to form a V-shaped waveform.

That is, referring to FIG. 1, the stringer 10a according to the present invention uses a strip plate system having a vertically long rectangular cross section, and changes the height of the upper end of the strip plate into a deformed W shape in the span direction. Let That is, the height of the upper end of the strip is the maximum height at the cross girder support positions at both ends of the span,
At the center of the span, there is a maximum value that is lower than the horizontal girder support position, and the height is the minimum value (also the minimum value) at a position 15% to 25% of the span length away from the horizontal girder support position.
Gives the height distribution so that Here, it is assumed that the height of the strip changes smoothly in a W shape.

When only the out-of-plane pressure acts on the outer plate 13 and the axial tension of the stringer 10a does not exist, as shown in FIG. 5, the minimum value of the strip height is from the cross girder support position. Positions separated by about 21.1% of the span are theoretically given as the optimal solution. On the other hand, in the general member of the hull in which the out-of-plane pressure and the axial tensile force are superposed on each other, in the range of 0.15 s to 0.35 s (s is the span length) depending on the ratio of these two loads. There is an optimal solution. Therefore, in order to deal with all possible changes in the load ratio, 0.15 s ~
By selecting a value in the range of 0.35 s and arranging the dimensions according to this, although not optimal, it is possible to achieve weight reduction and improvement in economy as compared with the conventional method.

The height h of the stringer 10a in the structure of the present invention.
Is the following formula (1) using the coordinate x that represents the position in the longitudinal direction.
Can be shown as h (x) = α−β (x / 1) ² δ + β (x / 1) ² δ, (when 0 ≦ x ≦ l) (1) where s: transverse beam span x = 0 and x = 1: horizontal position α, β, δ: undetermined constant (provided that γ> 0).

However, the following restrictions are imposed on the undetermined constants in accordance with the conditions shown in the above equations (1) and (2). α> 0 and β> 0 (2) 0.250>γ> 0.1827 (3) Specific values of α and β are the horizontal position (x = 0 or In (s), the generated stress under the external load condition in which the out-of-plane pressure and the axial force are superposed on the beam cross section constituted by the stringer 10a and the outer plate 13 is exactly the same as the allowable stress, and the transverse beam position ( x
= 0 or s), it is determined from the condition (dσ / dx) _{at x = 0} = 0 or (dδ / dx) _{at x = s} = 0 that the generated stress (σ) does not change in the longitudinal direction.

In the structure of the present invention, the weight can be reduced as compared with the conventional structure while satisfying the allowable stress for preventing the yielding of the steel material.

[0015]

According to such a stringer, since the upper end line thereof is formed into a wavy shape with a deformed shape, the weight can be considerably reduced, that is, the cost of the entire outer plate structure can be reduced.

In summary, according to the first aspect of the invention, a plurality of long parallel stringers each having a rectangular cross section in an upright posture extending in parallel in the vertical direction at a set span in the horizontal direction, and the above stringers. the lower end with the at vertical setting span on the same horizontal plane of the Ru lattice structure name and a plurality of parallel cross beams of T-shaped cross-section, each extending in the phase transmural manner fitted to parallel to the transverse direction from each other through the slot In the hull skin structure that is fixed to the upper surface of the horizontal skin, the longitudinal members of the hull shall have the maximum height at the cross girder support position, and the height at the center of the longitudinal span shall be lower than the height at the cross girder support position. While having a maximum value,
Variant W whose top height changes smoothly so that it has local minimum values at two positions slightly closer to the center from both ends of the same span
The present invention is extremely useful industrially because a lightweight and economical hull skin structure can be obtained by using a stringer having a letter-shaped upper end curve.

According to a second aspect of the present invention, in the first aspect, the variant having the minimum value at each position 15% to 25% of the longitudinal span length away from the cross girder supporting position of the stringer. By having a W-shaped upper end line, a lightweight and economical hull skin structure can be obtained, so the present invention is extremely useful in industry.

[Brief description of drawings]

FIG. 1 is a side view showing a stringer according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an inner surface structure of a conventional hull skin plate.

FIG. 3 is a cross-sectional view showing a T-shaped stringer as an example of the stringer of FIG.

FIG. 4 is a sectional view showing a stringer without a face member, which is different from FIG.

5 is a diagram showing a moment acting on the outer plate structure of FIG. 1. FIG.

[Explanation of symbols]

10a Longitudinal material 11 horizontal girders 13 outer plate 20 faces 22 strip s transverse span

Claims (2)

(57) [Claims] 1. A plurality of long parallel stringers each having a rectangular cross section in an upright posture extending in a vertical direction in parallel with a set span in the horizontal direction, and each of the stringers in a set span in the vertical direction. each fixing a lower end on the same horizontal plane phase transmural manner fitted to the lattice structure ing of a plurality of parallel cross beams of T-shaped cross-section extending parallel to the transverse direction from each other through the slot on the upper surface of the horizontal outer plate In the hull skin structure, the maximum length of each stringer is at the cross girder support position, and the vertical span center has a maximum value of a height lower than the height at the cross girder support position and the same span. The outer shell structure of the hull is characterized by being a stringer having a deformed W-shaped upper end curve in which the upper end height smoothly changes so as to have minimum values at two positions slightly closer to the center from both ends of the. 2. The method according to claim 1, wherein 15% to 25% of the longitudinal span length from the cross girder support position of the stringer.
A hull skin structure characterized by having a modified W-shaped upper end line each having its minimum value at distant positions.