JPS6231358Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a panel structure used for, for example, the outer panel, deck, bulkhead, etc. of a ship.

Conventional technology and its problems For example, the top plate (inner bottom plate) of a ship's double bottom tank, as shown in Figures 1 and 2,
It has a panel structure in which a plurality of large bones (floors) 2 and small bones (stiffeners) 3 are fixed to one side of a steel plate 1. The required thickness of such steel plates, which are subjected to vertical loads such as water pressure, by classification societies is proposed mainly based on the plastic collapse of panels whose periphery is fixed with small and large bones. In other words, the load at which the first plastic hinge is generated when the short side of the panel between the small bones of the panel subjected to the vertical load is subjected to an evenly distributed load is considered as the plastic collapse load of this panel. The formula is the standard.

Here, t is the thickness of the panel, s is the span of the strip, σ is the yield stress of the strip, and w is the collapse load of the strip. The bending moment distribution within the elastic region of the strip subjected to a uniformly distributed load as shown in Figure 2A is as shown in Figure 2B, and the bending moment is at point A on the small bone 3.
It reaches its maximum at point B, which is at the center of the span, and becomes half of it at point B at the center of the span. On the other hand, looking at the plastic strength of the panel, point A on the ossicle 3 at the center between the large bones 2, point C on the large bone 2 at the center between the 3 bones, and point C on the large bone 2 at the center between the 2 large bones and the center between the 3 small bones. It is known that a plastic hinge occurs in the order of point B, and as shown by the arrow in FIG. 3, the plastic hinge develops and takes a roof-type collapse mode. The thickness t of the steel plate 1 is 13 mm, the span s1 between the large bones 2 is 2115 mm, the span s between the small bones 3 is 925 mm, and the steel plate 1 of the panel is
As a result of examining the occurrence and development of plastic hinges on the surface using an elastic-plastic analysis program, we found that first, a plastic hinge occurs at point A under a vertical load of approximately 11.4t/ ^m2 , and then at point C, approximately
With a load of 16.5t/ ^m2 , approximately
It has been confirmed that a plastic hinge occurs at a load of 20.0t/m ² and that the plastic hinge develops in the direction of the arrow in Figure 3 as the vertical load increases. In this way, the strength of the panel is determined at point A, and when constructing a panel using steel plates with uniform thickness as in the past, other parts must be adjusted to meet the strength requirements at point A. There are problems in that the board becomes thicker than necessary and the weight of the entire panel increases.

Additionally, tank walls that have already been constructed may become insufficient in thickness due to changes in design conditions. In such cases, reinforcement measures include completely replacing the steel plates and reducing the span between the small bones. Possible options include adding new ossicles between existing ossicles, and adding new large bones between existing ossicles to reduce the aspect ratio of the panel. However, when replacing the steel plate with one whose overall thickness is uniformly increased, the weight of the panel increases significantly as described above, and when adding aggregate, the side where the aggregate is placed becomes In the case of tanks, etc., it is difficult to install new aggregate, and the costs associated with reinforcement measures are extremely high.

The purpose of this invention is to solve the above problems and provide a panel structure that is lightweight and strong, and that can be easily modified from conventional panels that have already been constructed.

Means for solving the problem In the panel structure according to this invention, a plurality of small bones are fixed to one side of a steel plate, and a double-clad plate is fixed to the other side of the steel plate at the corresponding position to the small bones and at the center of the span between the small bones. It is characterized by the fact that

Function: Double clad plates are fixed to the steel plate at positions corresponding to the small bones and at the center of the span between the small bones, increasing the collapse load of the panel and increasing its strength.Moreover, the entire plate thickness is uniform. Although it has the same high strength, the overall weight increase is small compared to the case where the size is increased to 1. Also,
A double clad plate is fixed to the opposite side of the steel plate to the small ribs, so when reinforcing an already constructed tank wall, etc., even if aggregate is placed on the tank side, double clad plate is fixed to the steel plate. Modification work to secure the tank can be carried out from outside the tank.

Example Before describing the example of this invention, a comparative example will be described with reference to FIGS. 4 to 6.

The panel structure of this comparative example is a modified version of the panel shown in Figures 1 to 3 with reinforcement measures taken.
The arrangement of the steel plate 1, large bones 2, and small bones 3 is as follows.
This is the same as in the case of FIGS. And steel plate 1
On the surface opposite to the ossicles 3, a plurality of elongated double plates (doublers) 4 are fixed only at positions corresponding to the ossicles 3.

As a result of analysis using the same elastoplastic analysis program as described above, it was found that by fixing the double clad plate 4 at the position corresponding to the small bone 3, the collapse load of the panel increased compared to the cases shown in Figs. 1 to 3. It was confirmed that the strength was increased. That is, in FIGS. 4 to 6, the width b of the double clad board 4 is 200 mm, and the board thickness t1.
is 8 mm, approximately
At a vertical load of 19.9t/ ^m2 , a plastic hinge first occurs,
Next, point C, point A, and point B each have approximately 21.9,
A plastic hinge occurs at a load of 23.3, 27.9t/ ^m2 ,
As the vertical load increases, the plastic hinge develops in the direction of the arrow in FIG.

Next, one embodiment of the present invention will be described with reference to FIGS. 7 to 9.

The panel structure of this example is also a modification of the panel shown in Figures 1 to 3 by taking reinforcement measures.
The arrangement of the steel plate 1, large bones 2, and small bones 3 is as follows.
This is the same as in the case of FIGS. And steel plate 1
On the side opposite to the ossicles 3, a plurality of elongated double plates (doublers) 4 are fixed at positions corresponding to the ossicles 3 and at the center of the span s between the ossicles 3.

As a result of analysis using the same elastic-plastic analysis program as described above, the comparative examples shown in FIGS. 4 to 6 were obtained by fixing the double-clad plate 4 at the position corresponding to the ossicles 3 and at the center of the span s between the ossicles 3. It was confirmed that the collapse load of the panel was further increased compared to the case of , and the strength was increased. That is, in FIGS. 7 to 9, the width b of the double clad board 4 is 200 mm, and the board thickness t1.
If it is 8mm, then at point A it will be about 23.0t/
A vertical load of m ² produces a plastic hinge, then points C,
Points E and D at the widthwise side ends of the double-clad plate 4 at the center of the span s1 between the large bones 2 and the center of the span s between the small bones 3
A plastic hinge occurs at loads of approximately 27.0, 33.0, and 35.0 t/m ² in this order, respectively, and as the vertical load increases, the plastic hinge develops in the direction of the arrow in Figure 9.

The width b and thickness t1 of the double-clad board 4 are appropriately determined in consideration of the maximum vertical load acting on the panel, the span s between the small bones 3, and the like.

Effects of the invention According to the panel structure of this invention, double-clad plates are fixed at positions corresponding to the small bones of the steel plate and at the center of the span between the small bones, which increases the collapse load of the panel and reduces the overall plate thickness. It has the same great strength as a larger panel, and can be constructed to be lighter than a conventional panel in which the overall thickness is uniformly increased. In addition, since the double-clad plate is fixed to the side opposite to the small bones of the steel plate, when reinforcing an already constructed tank wall, etc., even if aggregate is placed on the tank side, double-clad plate is fixed to the steel plate. The modification work of fixing the cladding can be done from the outside of the tank, making the work simple, shortening the construction period, and minimizing the cost required for modification.

[Brief explanation of the drawing]

1 to 3 show a conventional example, FIG. 1 is a partial plan view of the panel, FIG. 2 is an enlarged cross-sectional view along the line of FIG. 1 and its bending moment diagram, and FIG. 3 is a diagram of FIG. Figures 4 to 6 show comparative examples; Figures 4 to 6 show comparative examples; An enlarged plan view, Fig. 5 is a sectional view along the line of Fig. 4, Fig. 6
The figure is an enlarged view of part a in Figure 4, which is equivalent to Figure 3 and shows the results of the analysis using the above-mentioned elastic-plastic analysis program.
Examples are shown in FIGS. 4, 5, and 6, respectively.
This is a drawing corresponding to the figure. 1...Steel plate, 3...Small ribs, 4...Double clad plate.

Claims (1)

[Scope of utility model registration request] A panel structure characterized in that a plurality of ossicles are fixed to one side of a steel plate, and a double-clad plate is fixed to the other side of the steel plate at a position corresponding to the ossicles and at the center of the span between the ossicles.