JPS6243912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a panel structure used for, for example, a ship's shell, deck, bulkhead, etc.

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 by classification societies for such steel plates, which are subjected to vertical loads such as water pressure, is determined based primarily 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 a uniform thickness as in the past, other parts of the plate are required to meet the strength requirements at point A. There are problems in that the thickness becomes thicker than necessary and the weight of the entire panel increases.

An object of the present invention is to solve the above problems and provide a lightweight and strong panel structure.

Means for Solving the Problems In the panel structure according to the present invention, one side of a metal plate is formed flat, and a plurality of protrusions are formed on the other side so that the plate thickness increases at regular intervals. The ossicles are fixed at positions corresponding to every other protrusion on one side of the metal plate, and the thickness of the plate is thicker at the position corresponding to the ossicles and at the center of the span between the ossicles. It is something to do.

Function: By forming protrusions on the metal plate at the positions corresponding to the small bones and at the center of the span between the small bones, and making the plate thicker, the collapse load of the panel increases and its strength increases, and the overall strength of the metal plate increases. Compared to a case where the plate thickness is uniformly increased, the overall weight increase is small even though it has the same great strength.

Examples Before describing examples of the present invention, a comparative example will be described with reference to FIGS. 4 to 6.

In the panel structure of this comparative example, one side of the steel plate 11 is formed flat, and a plurality of protrusions 12 of the same size and square cross section are integrally formed at regular intervals on the other side, and the plate thickness is constant. It gets thicker at intervals. A plurality of small bones 3 are formed on the flat surface 11a of the steel plate 11.
is fixed at a position opposite to the protrusion 12, and the small bone 3
The thickness of the plate is increased only at the position corresponding to , and a plurality of large bones 2 are fixed at right angles to small bones 3.

As a result of analysis using the same elastic-plastic analysis program as above, it was found that by increasing the plate thickness at the position corresponding to the small bone 3, the collapse load of the panel increased compared to the cases shown in Figures 1 to 3, resulting in greater strength. It was confirmed that it would happen. That is, in FIGS. 4 to 6, the plate thickness t of the flat portion on both sides of the steel plate 11 is 13 mm, and the protrusion 1 with a rectangular cross section is formed at a position corresponding to the small bone 3.
When the width b of 2 is 200 mm, the plate thickness t1 of this part is 21 mm, and other conditions are the same as in Figs. 1 to 3, the protrusion 5 and Approximately at point D at the boundary with the flat part on both sides
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 loads of 23.3 and 27.9t/ ^m2 ,
As the vertical load increases, a 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.

In the panel structure of this embodiment as well, one side of the steel plate 13 is formed flat, and a plurality of protrusions 14 of the same size and square cross section are integrally formed on the other side at regular intervals. A plurality of small bones 3 are fixed to the flat surface 13a of the steel plate 13 at positions opposite to every other protrusion 14, and the plate thickness at the position corresponding to the small bones 3 and the center of the span s between the small bones 3 is fixed to the flat surface 13a of the steel plate 13. is getting thicker. The rest is the same as in the comparative example.

As a result of analysis using the same elastic-plastic analysis program as described above, it was found that by increasing the plate thickness at the position corresponding to the small bones 3 and at the center of the span s between the small bones 3, the comparative example shown in Figs. In comparison, it was confirmed that the collapse load of the panel increased and its strength increased. That is, in FIGS. 7 to 9, the width b of the protrusion 14 with a rectangular cross section formed at the position corresponding to the small bones 3 of the steel plate 13 and at the center of the span s between the small bones 3 is 200 mm, and the plate thickness at this part is t1 to 21
mm, and other conditions are the same as in Figures 4 to 6, a plastic hinge occurs first at point A under a vertical load of approximately 23.0t/ ^m2 , then at point C, the large bone 2
At the center of the span s1 between the ossicles 3, a plastic hinge is formed at points E and D at the boundary between the ridge 14 at the center of the span s and the flat portion on both sides under loads of approximately 27.0, 33.0, and 35.0t/ ^m2, respectively. occurs, and as the vertical load increases, the plastic hinge develops in the direction of the arrow in FIG.

Note that the thickness t of the flat portion on both sides of the steel plate 13 and the width b and thickness t1 of the protrusion 14 are appropriately determined in consideration of the maximum vertical load acting on the panel, the span s between the small bones 3, etc. .

FIG. 10 shows an embodiment different from the above.

In the panel structure of this embodiment, a relatively large protrusion 16 and a relatively small protrusion 1 are provided on one side of the steel plate 15.
7 are formed alternately at regular intervals.
A plurality of ossicles 3 are fixed to the flat surface 15a of the steel plate 15 at positions opposite to the large ridges 16, and the small ridges 17 are located at the center of the span s between the ossicles 3. The rest is the same as in the case of FIGS. 7 to 9.

This invention can be applied to panel structures using not only steel plates but also any metal plates such as aluminum plates.

Effects of the Invention According to the panel structure of the present invention, protrusions are formed at positions corresponding to the small bones of the metal plate and at the center of the span between the small bones, and the plate thickness is increased, so that a lightweight and strong panel can be obtained. It has the same great strength as when the overall plate thickness is increased, and the overall weight increase is smaller than the conventional one where the overall plate thickness is uniformly thick. I'll try it.

[Brief explanation of the drawing]

Figures 1 to 3 show a conventional example, Figure 1 is a partial plan view of the panel, Figure 2 is an enlarged sectional view along the line of Figure 1 and its bending moment diagram, and Figure 3 is Figure 1 a. Figures 4 to 6 show comparative examples; Figures 4 to 6 show comparative examples; Enlarged plan view, Fig. 5 is a sectional view taken along the line of Fig. 4, Fig. 6
The figure is an enlarged view of part a in Figure 4 and corresponds to Figure 3 showing the results of analysis using the above-mentioned elastic-plastic analysis program. Figures 7, 8, and 9 show embodiments of the present invention, respectively. 4, 5 and 6, and FIG. 10 is a drawing corresponding to FIG. 8 showing another embodiment of the present invention. 13, 15... Steel plate (metal plate), 14, 16, 1
7... Projection, 13a, 15a... Flat surface.

Claims (1)

[Claims] 1 One side of a metal plate is formed flat, and the other side has a plurality of protrusions formed at regular intervals so that the plate thickness becomes thicker, and a plurality of small bones are formed on one side of the metal plate at every other line. The panel structure is fixed at a position corresponding to the protrusion of the ossicle, and has a thick plate thickness at a position corresponding to the ossicles and at the center of the span between the ossicles.