KR20190044368A - Angular structure with improved fracture toughness and manufacturing method and pressure tank - Google Patents

Abstract

The present invention relates to a square-shaped structure with improved fracture toughness and a manufacturing method thereof, and a square-shaped pressure tank, which can improve stability and reliability by dispersing stress focused on a corner of the square-shaped structure, including: a first wall body at which a first inner surface is formed; a second wall body which is connected to the first wall body, and at which a second inner surface is formed while being connected to the first inner surface around a first corner unit; and a first stress dispersion unit formed at the first corner unit so as to disperse stress focused on the first corner unit.

Description

Technical Field [0001] The present invention relates to a prismatic structure having improved fracture toughness, a manufacturing method thereof, and an angular structure with improved fracture toughness and manufacturing method and pressure tank,

The present invention relates to a prismatic structure having improved fracture toughness, a manufacturing method thereof, and a prismatic pressure tank, and more particularly, to a prismatic prism having improved fracture toughness and improved stability and reliability by dispersing stress concentrated at corners of a prismatic structure A structure, a manufacturing method, and a square-shaped pressure tank.

Liquefied natural gas (hereinafter referred to as "LNG") is a colorless transparent liquid obtained by cooling methane-based natural gas to about -162 ° C. and liquefying it. / 600. ≪ / RTI > Therefore, it is very efficient to transport liquefied LNG when transporting natural gas. For example, an LNG carrier that can transport (transport) LNG is used. In addition, shipments of PSV (platform supply vessel), passenger ship, bulk cargo ship, container ship, chemical ship carrier, crude oil carrier, refining oil carrier, etc., which use LNG as propellant fuel due to environmental problems and high oil prices, . Accordingly, ships using LNG carriers or LNG as propellant fuel use pressure tanks to store LNG.

Generally, the shape of the pressure tank often takes the form of a cylinder. The reason is that the circular shape is the best form to withstand pressure when viewed in cross section. However, the volume efficiency must be high for transport using pressure tanks. The volume efficiency of the hexahedral pressure tanks is at least 21% to 50% greater than that of the cylinder type pressure tanks.

As such, a method of maximizing the volumetric efficiency is to make a pressure tank having a square cross section. However, the conventional pressure tank made of a hexagonal prismatic rectangular structure having a square cross-section is disadvantageous in that, There is a problem that it can occur. Therefore, in the square structure, stress is concentrated on the corner portion or the square portion, which causes structural weakness. Therefore, despite the advantages of the excellent storage capacity of the square structure, there is a restriction in use.

The present invention is to solve various problems including the above-mentioned problems, and it is a technology applicable to rectangular storage tanks and pressure vessels as well as pressure tanks for storing LNG, The present invention also provides a prismatic structure having improved fracture toughness, which can ensure stability and reliability through stress dispersion, a manufacturing method thereof, and a prismatic pressure tank. However, these problems are exemplary and do not limit the scope of the present invention.

According to one aspect of the present invention, there is provided a prismatic structure having improved fracture toughness. The prismatic structure having improved fracture toughness includes: a first wall on which a first inner surface is formed; A second wall connected to the first wall and having a second inner surface connected to the first inner surface through a first corner; And a first stress dispersing portion formed on the first corner portion to disperse stress concentrated on the first corner portion.

In the prismatic structure having improved fracture toughness, the first stress dispersing portion may be at least one or more fine groove portions formed to extend from the first inner surface to the second inner surface.

In the prismatic structure having improved fracture toughness, the fine groove portion has a first portion formed on the first inner surface and formed at a right angle to the first corner portion; And a second portion formed on the second inner surface, the second portion being formed at right angles to the first corner in a direction opposite to the first portion.

In the prismatic structure having improved fracture toughness, a plurality of the fine grooves may be spaced apart from each other by a predetermined distance along the first corner.

In the prismatic structure having improved fracture toughness, a third inner surface connected to the first wall and the second wall and connected to the first inner surface and the second inner surface at a boundary between the second corner and the third corner, A third wall formed; A second stress dispersing portion formed in the second corner portion to disperse stress concentrated in the second corner portion; And a third stress dispersing portion formed on the third corner portion so as to disperse stress concentrated on the third corner portion.

In the prismatic structure having improved fracture toughness, the second stress dispersing portion is at least one or more fine groove portions formed so as to extend from the first inner surface to the third inner surface, At least one or more fine grooves may be formed to extend from the first inner surface to the third inner surface.

A fourth stress distribution portion formed in the vertex portion so as to disperse stress concentrated on a vertex portion where the first edge portion, the second edge portion, and the third edge portion meet, in the prismatic structure having improved fracture toughness, ; ≪ / RTI >

In the prismatic structure having improved fracture toughness, the fourth stress dispersing portion may be at least one loop fine groove portion extending from the first inner surface to the third inner surface through the second inner surface in a loop shape.

In the rectangular prism structure having improved fracture toughness, a plurality of the loop fine grooves may be spaced apart from each other by a predetermined distance in the center direction of the vertex portion.

In the prismatic structure having improved fracture toughness, the fourth stress dispersing portion may be a cylindrical hole portion or a spherical hole portion formed in the vertex portion.

According to one aspect of the present invention, a method of manufacturing a prismatic structure having improved fracture toughness is provided. A method for manufacturing a prismatic structure having improved fracture toughness includes the steps of forming a first wall on which a first inner surface is formed and a second inner surface connected to the first wall and connected to the first inner surface at a boundary between the first corner portions Forming a second wall; And a first stress dispersing portion formed of at least one fine groove portion formed to extend from the first inner surface to the second inner surface in the first corner portion so as to disperse stress concentrated on the first corner portion The method comprising the steps of:

In the method of manufacturing a prismatic structure having improved fracture toughness, the fine groove portion may be formed by any one of cutting, discharging, and laser processing.

According to one aspect of the present invention, there is provided a prismatic pressure tank improved in fracture toughness. The prismatic pressure tank having improved fracture toughness includes: a first wall formed with a first inner surface; A second wall connected to the first wall and having a second inner surface connected to the first inner surface through a first corner; A third wall connected to the first wall and the second wall and having a third inner surface connected to the first inner surface and the second inner surface at a boundary between the second corner and the third corner; A first stress dispersing portion formed in the first corner portion to disperse stress concentrated on the first corner portion; A second stress dispersing portion formed in the second corner portion to disperse stress concentrated in the second corner portion; And a third stress dispersing portion formed on the third corner portion so as to disperse stress concentrated on the third corner portion.

According to the prismatic structure having improved fracture toughness, manufacturing method, and prismatic pressure tank according to an embodiment of the present invention, as described above, it is possible to use not only LNG storage pressure tanks but also prismatic storage tanks and pressure vessels Stability and reliability of the prismatic structure can be easily ensured through stress dispersion by micro-grooving technique of stress concentrated at corners.

Accordingly, by improving the fracture toughness only by micro-grooving the fragile portion of the prismatic structure, it is possible to improve the fracture toughness, which has the effect of solving the destruction due to the stress concentration phenomenon of the structure, which is the biggest disadvantage of the prismatic structure, A square structure, a manufacturing method, and a rectangular pressure tank can be realized. Of course, the scope of the present invention is not limited by these effects.

1 is a perspective view schematically showing a prismatic structure having improved fracture toughness according to an embodiment of the present invention.
Fig. 2 is a perspective view showing a first stress distribution portion of the prismatic structure having improved fracture toughness shown in Fig. 1;
Figs. 3 and 4 are cross-sectional views showing a first stress distribution portion of the prismatic structure having improved fracture toughness shown in Fig. 1; Fig.
Figs. 5 and 6 are stress dispersion diagrams showing simulation results before and after machining of the first stress dispersion portion of the prismatic structure with improved fracture toughness shown in Fig. 1. Fig.
FIGS. 7 to 9 are perspective views showing a fourth stress distribution portion of the prismatic structure having improved fracture toughness shown in FIG. 1; FIG.
Figs. 10 and 11 are cut-away sectional views showing the fourth stress dispersing portion of Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, It is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the thickness and size of each layer are exaggerated for convenience and clarity of explanation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings schematically showing ideal embodiments of the present invention. In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention should not be construed as limited to the particular shapes of the regions shown herein, but should include, for example, changes in shape resulting from manufacturing.

FIG. 1 is a perspective view schematically showing a prismatic structure 100 improved in fracture toughness according to an embodiment of the present invention. FIG. 2 is a cross- Fig. 3 and 4 are cross-sectional views showing a first stress distribution portion 50 of the prismatic structure 100 with improved fracture toughness in FIG. 1, and FIGS. 5 and 6 are cross- Is a stress dispersion diagram showing the results of simulation before and after the processing of the first stress distribution portion 50 of the prismatic structure 100. [

1, a prismatic structure 100 with improved fracture toughness according to an embodiment of the present invention includes a first wall 10, a second wall 20, and a first stress And a dispersion unit 50. [

2, the first wall 10 is formed with a first inner surface S1, and the second wall 20 is connected to the first wall 10 and has a first edge E1, A second inner surface S2 connected to the first inner surface S1 may be formed. For example, the first wall 10 and the second wall 20 are part of a pressure tank made up of a hexagonal prismatic structure 100 having a rectangular cross-section. The first wall 10 and the second wall 20 are formed on the first inner surface S1 of the first wall 10, And the second inner surface S2 of the second wall 20 can form part of the inner space of the prismatic structure 100. [

More specifically, the first wall 10 and the second wall 20 may be a structure having adequate strength and durability to withstand the pressure of LNG or the like stored in the inner space. For example, the first wall 10 and the second wall 20 may be a structure selected from a material selected from the group consisting of steel, stainless steel, aluminum, magnesium, and zinc. However, the first wall 10 and the second wall 20 are not limited to those shown in Fig. 2, and members of extremely various materials capable of withstanding pressure of LNG stored in the inner space can be applied.

As shown in FIG. 2, the first stress dispersing portion 50 may be formed in the first edge portion E1 so as to disperse stress concentrated on the first edge portion E1. For example, the first stress dispersing portion 50 may include at least one or more fine grooves 50 formed to extend from the first inner surface S1 of the first wall 10 to the second inner surface S2 of the second wall 20, (51). At this time, a plurality of the at least one fine groove portions 51 may be spaced apart from each other by a predetermined distance along the first corner E1. The dimensions such as the number of the fine grooves 51, the distance between the fine grooves 51, the width, the length and the depth of the fine grooves 51 are not limited to the specifications of the raw materials of the first wall 10 and the second wall 20 And internal characteristics such as strength and toughness, and can be appropriately selected according to need.

3, the fine groove portion 51 includes a first portion 51a formed on the first inner surface S1 and formed at right angles to the first corner portion E1, And a second portion 51b that is formed in the second portion S2 and is formed at a right angle to the first edge E1 in a direction opposite to the first portion 51a.

For example, the first portion 51a and the second portion 51b may meet in the vertical direction so that the cross section of the fine groove portion 51 may be formed as a whole. At this time, although not shown, a round shape may be formed in the corner portion to prevent stress from concentrating on a corner portion where the first portion 51a and the second portion 51b meet. The first portion 51a and the second portion 52b can be formed by simple mechanical processing using any one of cutting, discharging, and laser processing.

4, the fine grooves 52 of the first stress dispersing unit 50 may have a circular cross-sectional shape as a whole. As a result, since the fine groove portion 52 is formed in a circular shape as a whole and no corner portion is formed in the fine groove portion 52, it is possible to effectively prevent a phenomenon that stress concentrates even in the fine groove portion 52. [ This fine groove portion 52 can be easily machined by a machining tool such as a circular saw blade or the like, so that the machining time can be further shortened.

The method for manufacturing the prismatic structure 100 with improved fracture toughness includes the first wall 10 on which the first inner surface S1 is formed and the second wall 10 connected to the first wall 10, And a second inner surface S2 connected to the first inner surface S1 at a boundary between the first inner surface S1 and the first inner surface S1, The step of forming the first stress dispersing portion 50 including the at least one fine groove portion 51 formed to extend from the first inner surface S1 to the second inner surface S2 at the first corner E1 At this time, the fine groove portion 51 may be formed by any one of cutting, discharging, and laser processing.

5 and 6, before and after the simulation of the first stress distribution portion 50 made up of the fine groove portions 51 in the prism structure 100, It can be confirmed that the stress at one edge E1 is effectively dispersed. At this time, when stress is more concentrated on the fine groove portion 51 and the fine groove portion 51 advances, the effect of stress dispersion by the fine groove portion 51 can be further increased. Accordingly, the stress applied to the first edge portion E1 The fracture toughness improving effect can be further maximized.

Accordingly, the prismatic structure 100 having improved fracture toughness according to an embodiment of the present invention is applicable to rectangular storage tanks and pressure vessels as well as pressure tanks for storing LNG. Stability and reliability of the prismatic structure can be easily secured through the stress dispersion by the fine groove processing technique.

Therefore, by improving the fracture toughness only by micro-grooving the fragile portion of the prismatic structure, it is possible to eliminate the destruction due to the stress concentration phenomenon, which is the biggest disadvantage of the prismatic structure, by a simple method. Accordingly, by applying a pressure tank made of a prismatic structure having improved fracture toughness to a ship using LNG transportation shelves or LNG as a propellant fuel, it is possible to enhance the storage volume efficiency of the LNG while ensuring the safety of the pressure tank, Can be used.

The prismatic structure 100 having improved fracture toughness can be used as an oil / gas transportation pipe requiring high mechanical properties in a cryogenic environment, a storage vessel such as ethylene or LPG, a steel pipe for an oil sand slurry pipe, a LNG container cargo hold structure And similar marine transportation or petrochemical plants.

FIGS. 7 to 9 are perspective views showing a fourth stress dispersing portion 60 of the prismatic structure 100 with improved fracture toughness in FIG. 1, and FIGS. 10 and 11 are perspective views showing the fourth stress dispersing portion 60 of FIG. Fig.

7, the prismatic structure 100 with improved fracture toughness according to an embodiment of the present invention is connected to the first wall 10 and the second wall 20, and the second corner portion A third wall 30 formed with a third inner surface S3 connected to the first inner surface S1 and the second inner surface S2 at a boundary between the second corner portion E2 and the third corner portion E3, (E3) so as to disperse the stress concentrated on the second stress dispersing portion and the third edge portion (E3) formed on the second edge portion (E2) so as to disperse the stress concentrated on the third edge portion (E2) And a third stress dispersing portion formed on the first stress dispersing portion.

More specifically, the second stress dispersing portion is at least one or more fine groove portions formed so as to extend from the first inner surface S1 to the third inner surface S3, and the third stress dispersing portion includes a second inner surface S2, At least one or more fine grooves may be formed to extend from the first inner surface S3 to the third inner surface S3. Here, the fine grooves of the second stress dispersing unit and the third stress dispersing unit may have the same structure and function as those of the fine grooves 51 of the first stress dispersing unit 50. Therefore, detailed description is omitted.

7, in order to disperse the stress concentrated on the vertex V at which the first edge E1, the second edge E2 and the third edge E3 meet, And the fourth stress dispersing portion 60 may be formed in the portion V. [ More specifically, the fourth stress dispersing portion 60 includes at least one loop fine groove portion (hereinafter referred to as " loop stressed portion ") extending from the first inner surface S1 to the third inner surface S3 via the second inner surface S2, 61).

At this time, a plurality of the loop fine grooves 61 may be spaced apart from each other by a predetermined distance in the center direction of the vertex portion V, and the loop fine grooves 61 formed on the inner surfaces S1, S2, And may be formed into a straight shape 61a. 8, the loop fine groove portions 61 formed on the inner surfaces S1, S2, and S3 may be formed as arc shapes 61b, respectively. The loop fine groove portion 61 can be formed by simple mechanical processing using any one of cutting, discharging and laser machining.

9 and 10, the fourth stress dispersing portion 60 may be a cylindrical hole portion 62 formed in the vertex portion V, and as shown in FIG. 11, Or a spherical hole portion 63 formed in the vane. Since the cylindrical hole portion 62 or the spherical hole portion 63 of the fourth stress distribution portion 60 can be easily formed only by machining using an end mill or a globular shape drill, 60 can be further simplified.

Accordingly, the prismatic structure 100 having improved fracture toughness according to an embodiment of the present invention is applicable to rectangular storage tanks and pressure vessels as well as pressure tanks for storing LNG. And the stability and reliability of the prismatic structure can be easily secured through the stress dispersion by the fine groove processing technique.

Therefore, by improving the fracture toughness only by micro-grooving the fragile portion of the prismatic structure, it is possible to eliminate the destruction due to the stress concentration phenomenon, which is the biggest disadvantage of the prismatic structure, by a simple method. Accordingly, by applying a pressure tank made of a prismatic structure having improved fracture toughness to a ship using LNG transportation shelves or LNG as a propellant fuel, it is possible to enhance the storage volume efficiency of the LNG while ensuring the safety of the pressure tank, Can be used.

The prismatic structure 100 having improved fracture toughness can be used as an oil / gas transportation pipe requiring high mechanical properties in a cryogenic environment, a storage vessel such as ethylene or LPG, a steel pipe for an oil sand slurry pipe, a LNG container cargo hold structure And similar marine transportation or petrochemical plants.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: first wall
20: second wall
30: Third wall
50: first stress dispersion portion
60: second stress distribution portion
S1: First inner surface
S2: second inner surface
S3: Third inner surface
E1: first corner portion
E2: second corner portion
E3: Third corner portion
V: Corner portion
100: Angular structure with improved fracture toughness

Claims (13)

A first wall on which a first inner surface is formed;
A second wall connected to the first wall and having a second inner surface connected to the first inner surface through a first corner; And
A first stress dispersing portion formed in the first corner portion to disperse stress concentrated on the first corner portion;
Wherein the structure has an improved fracture toughness. The method according to claim 1,
Wherein the first stress dispersing portion comprises:
And at least one or more fine grooves formed to extend from the first inner surface to the second inner surface to improve the fracture toughness. 3. The method of claim 2,
The micro-
A first portion formed on the first inner surface and formed at a right angle to the first corner; And
A second portion formed on the second inner surface and formed at a right angle to the first corner in a direction opposite to the first portion;
Wherein the structure has an improved fracture toughness. 3. The method of claim 2,
The micro-
Wherein a plurality of the protrusions are spaced apart from each other by a predetermined distance along the first corner. The method according to claim 1,
A third wall connected to the first wall and the second wall and having a third inner surface connected to the first inner surface and the second inner surface at a boundary between the second corner and the third corner;
A second stress dispersing portion formed in the second corner portion to disperse stress concentrated in the second corner portion; And
A third stress disperser formed in the third corner portion to disperse stress concentrated in the third corner portion;
Further comprising: an elongate structure having improved fracture toughness. 6. The method of claim 5,
Wherein the second stress dispersing portion is at least one or more fine groove portions formed to extend from the first inner surface to the third inner surface,
Wherein the third stress dispersing portion is at least one or more fine grooves formed to extend from the second inner surface to the third inner surface. 6. The method of claim 5,
A fourth stress dispersing portion formed in the vertex portion to disperse stress concentrated on the vertex portion where the first edge portion, the second edge portion, and the third edge portion meet;
Further comprising: an elongate structure having improved fracture toughness. 8. The method of claim 7,
Wherein the fourth stress dispersing portion comprises:
And at least one loop fine groove portion extending from the first inner surface to the third inner surface through the second inner surface in a loop shape. 9. The method of claim 8,
The loop micro-
Wherein a plurality of the protrusions are spaced apart from each other by a predetermined distance in the center direction of the vertex portion. 8. The method of claim 7,
Wherein the fourth stress dispersing portion comprises:
And a cylindrical hole portion or a spherical hole portion formed in the vertex portion. Forming a first wall on which a first inner surface is formed and a second wall connected to the first wall and formed with a second inner surface bounded by the first inner surface at a boundary between the first edge and the first wall; And
And a first stress dispersing portion formed of at least one fine groove portion formed to extend from the first inner surface to the second inner surface to the first corner portion so as to disperse stress concentrated in the first corner portion step;
Wherein the fracture toughness is improved. 12. The method of claim 11,
The micro-
A method of manufacturing a prismatic structure having improved fracture toughness, which is formed by any one of cutting, discharging, and laser processing. A first wall on which a first inner surface is formed;
A second wall connected to the first wall and having a second inner surface connected to the first inner surface through a first corner;
A third wall connected to the first wall and the second wall and having a third inner surface connected to the first inner surface and the second inner surface at a boundary between the second corner and the third corner;
A first stress dispersing portion formed in the first corner portion to disperse stress concentrated on the first corner portion;
A second stress dispersing portion formed in the second corner portion to disperse stress concentrated in the second corner portion; And
A third stress disperser formed in the third corner portion to disperse stress concentrated in the third corner portion;
Wherein said pressure tank has an improved fracture toughness.

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