Connection structure of longitudinal frame ends of bulk carrier

Abstract

The invention discloses a connection structure for the ends of longitudinal ribs of a bulk carrier, which includes a connection plate; the web of a transverse strong frame is perpendicular to the deck longitudinal bone, the connection plate includes a plate body and a toe end, the toe end is connected to the plate body, the free edge of the plate body includes a first plate body edge and a second plate body edge, the free edge of the toe end includes a first toe end edge, a second toe end edge, a third toe end edge and a fourth toe end edge; the first toe end edge is connected to the second plate body edge; the first plate body edge is a straight line distributed obliquely upward, and the second plate body edge is an inwardly concave arc; the first toe end edge is a straight line parallel to the deck longitudinal bone; the fourth toe end edge is a straight line perpendicular to the deck longitudinal bone; the second toe end edge is an outwardly convex arc, and the third toe end edge is an inwardly concave arc. The connection structure of the invention can not only improve the fatigue strength of the connection of the longitudinal bone ends, alleviate the stress concentration problem at the connection, but also effectively control the weight of steel materials and reduce construction costs.

Description

Technical Field

[0001] The present invention relates to the technical field of ships, and in particular to a connection structure for ends of longitudinal frames of a bulk carrier. Background Art

[0002] The structural characteristics of bulk carriers determine that designers must focus on the fatigue strength of the longitudinal frame end connection. The existing connection form may lead to less than ideal fatigue strength at the longitudinal end connection and serious stress concentration problems, making it difficult to meet the requirements of the design specifications. To improve this situation, strengthening the longitudinal members near the connection is the most direct and rough way, but the weight of the steel will increase significantly, which is obviously not cost-effective. A more economical and effective means is to reduce the stress concentration factor of the longitudinal end connection, because the fatigue life of the structure is very sensitive to the stress concentration factor, and the two are roughly in a power function relationship. Reducing the stress concentration factor can greatly increase the fatigue life, which is greatly beneficial to the fatigue strength of the structure. To reduce its stress concentration factor, changing the form of the connection structure is an effective method.

[0003] The typical connection structures of the ends of the existing bulk carrier longitudinals are straight, key-shaped, and arc-shaped at the toe. The specifications specify the stress concentration factors of the above typical structures. Using this data to check the fatigue strength of the longitudinal end connection may not meet the requirements of the ship design specifications. It is necessary to thicken the corresponding longitudinal members or greatly increase the size of the connection structure to achieve a certain effect, which will lead to a significant increase in the weight of steel and an increase in construction costs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the above-mentioned defects in the prior art and provide a connection structure for the ends of the longitudinal frames of a bulk carrier.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A connection structure for the ends of longitudinal ribs of a bulk carrier, comprising connection plates respectively fixed to the deck longitudinals and transverse strong frames; the web of the transverse strong frames is perpendicular to the deck longitudinals, and the faceplate of the transverse strong frames is parallel to the deck longitudinals; the connection plate comprises a plate body and a toe end, the toe end is connected to the plate body, the free edge of the plate body comprises a first plate body edge and a second plate body edge connected in sequence, the free edge of the toe end comprises a first toe end edge, a second toe end edge, a third toe end edge and a fourth toe end edge connected in sequence; the first toe end edge is connected to the second plate body edge; the first plate body edge is a straight line distributed obliquely upward, and the second plate body edge is an inwardly concave arc; the first toe end edge is a straight line parallel to the deck longitudinals; the fourth toe end edge is a straight line perpendicular to the deck longitudinals. The plate body is a straight line, and the fourth toe edge is connected to the deck longitudinal bone; the height of the fourth toe edge is less than or equal to 15mm; the second toe edge is an outward convex arc, and the third toe edge is an inward concave arc; the plate body also includes a first fixed edge, and the first fixed edge is fixed to the web of the transverse strong frame; the distance from the first fixed edge to the fourth toe edge is L, and the value range of L is 400mm≤L≤1000mm; the height from the first toe edge to the deck longitudinal bone is H, and the value range of H is 100mm≤H≤200mm; the arc radius of the second toe edge is R2, and the value range of R2 is 50mm≤R2≤200mm; the arc radius of the third toe edge is R, and the value range of R is 100mm≤R≤300mm.

[0007] Preferably, the board body and the toe end are integrally formed.

[0008] Preferably, the plate body further comprises a second fixed edge, and the second fixed edge is fixedly connected to the deck longitudinal bone.

[0009] Preferably, the second fixed edge is perpendicular to the first fixed edge.

[0010] Preferably, the board body further comprises a third fixed edge, and the third fixed edge is fixed to a panel of the transverse strong frame.

[0011] Preferably, the toe end further includes a fourth fixed edge, and the fourth fixed edge is fixed to the deck longitudinal bone.

[0012] Preferably, the fourth fixing edge is perpendicular to the fourth toe-end edge.

[0013] Preferably, the second fixed edge and the fourth fixed edge are located on the same straight line.

[0014] Preferably, the fourth toe-end edge is parallel to the first fixed edge.

[0015] Preferably, the connection between the connecting plate and the transverse strong frame, and between the connecting plate and the deck longitudinal bone are all welded.

[0016] The beneficial effect of the present invention is that the connection structure of the present invention can meet the requirements of the ship design specification on the fatigue strength of the connection without thickening the corresponding components at the connection and without significantly increasing the size of the connection structure. The connection structure of the present invention can not only improve the fatigue strength of the longitudinal bone end connection and alleviate the stress concentration problem at the connection, but also effectively control the weight of steel materials and reduce construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a preferred embodiment of the present invention.

[0018] Figure 2 Schematic diagram of the finite element calculation model of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0019] A preferred embodiment is given below, and the present invention is described more clearly and completely in conjunction with the accompanying drawings.

[0020] like Figure 1 As shown, a connection structure of the ends of the longitudinal frames of a bulk carrier comprises a connection plate 30 respectively fixed to the deck longitudinals 10 and the transverse strong frames 20; the web 21 of the transverse strong frames 20 is perpendicular to the deck longitudinals 10, and the face plate 22 of the transverse strong frames 20 is parallel to the deck longitudinals 10; the connection plate 30 comprises a plate body 40 and a toe end 50, the toe end 50 is connected to the plate body 40, and the plate body and the toe end are integrally formed.

[0021] The free edge of the plate body 40 includes a first plate body edge 41 and a second plate body edge 42 connected in sequence.

[0022] The free edge of the toe end 50 includes a first toe end edge 51, a second toe end edge 52, a third toe end edge 53 and a fourth toe end edge 54 which are connected in sequence.

[0023] The first toe end edge 51 is connected to the second board body edge 42 ; the first board body edge 41 is a straight line extending obliquely upward, and the second board body edge 42 is an inwardly concave arc.

[0024] The first toe end edge 51 is a straight line parallel to the deck longitudinal bone 10; the fourth toe end edge 54 is a straight line perpendicular to the deck longitudinal bone 10, and the fourth toe end edge 54 is connected to the deck longitudinal bone 10; the height of the fourth toe end edge 54 is less than or equal to 15 mm.

[0025] The second toe end edge 52 is an outwardly convex arc, and the third toe end edge 53 is an inwardly concave arc.

[0026] There is a smooth transition between the first board body edge and the second board body edge, and there is a smooth transition between the first toe end edge, the second toe end edge and the third toe end edge; there is also a smooth transition between the free edge of the board body and the free edge of the toe end.

[0027] The plate body 40 further includes a first fixed edge, which is fixed to the web 21 of the transverse strong frame 20, that is, the first fixed edge coincides with the web 21 of the transverse strong frame 20. The fourth toe end edge 54 is parallel to the first fixed edge.

[0028] Since the first fixed edge coincides with the web 21 of the transverse strong frame 20 , the first fixed edge is not marked in the drawings.

[0029] The distance from the first fixed edge to the fourth toe end edge 54 is L, and the value range of L is 400mm≤L≤1000mm. Since the first fixed edge is no longer marked in the drawings, and the first fixed edge coincides with the web 21 of the transverse strong frame, the distance from the web 21 of the transverse strong frame to the fourth toe end edge 54 is L in the drawings.

[0030] The height from the first toe end edge 51 to the deck longitudinal bone 10 is H, and the value range of H is 100mm≤H≤200mm.

[0031] The arc radius of the second toe end edge 52 is R2, and the value range of R2 is 50 mm≤R2≤200 mm.

[0032] The arc radius of the third toe end edge 53 is R, and the value range of R is 100 mm≤R≤300 mm.

[0033] The plate body 40 further includes a second fixing edge 62, which is fixed to the deck longitudinal bone 10. The second fixing edge 62 is perpendicular to the first fixing edge.

[0034] The plate body 40 further includes a third fixed edge, which is fixed to the panel 22 of the transverse strong frame 20 , that is, the third fixed edge overlaps with the panel 22 of the transverse strong frame 20 .

[0035] Since the third fixing edge coincides with the panel 22 of the transverse strong frame, the third fixing edge is no longer marked in the drawings.

[0036] The toe end 50 also includes a fourth fixing edge, which is fixed to the deck longitudinal bone 10. The fourth fixing edge is perpendicular to the fourth toe end edge. The second fixing edge and the fourth fixing edge are located on the same straight line. Since the fourth fixing edge and the second fixing edge are located on the same straight line, the fourth fixing edge is no longer marked in the drawings.

[0037] The connection between the connecting plate 30 and the transverse strong frame 20 and between the connecting plate 30 and the deck longitudinal bone 10 are all welded.

[0038] The distance from the intersection of the virtual extension line of the first plate body edge 41 and the deck longitudinal 10 to the web 21 of the transverse stiffener is a, and the value of a can be determined according to the ship design specifications. The arc radius of the second plate body edge 42 is R1, and the value of R1 can be determined according to the value of a.

[0039] For the connection structure of the longitudinal frame ends, the design stress concentration factor can be replaced by the fine mesh finite element analysis method.

[0040] For the connection structure of this embodiment, the stress concentration factor is obtained by fine mesh finite element analysis method to verify that it has better fatigue strength.

[0041] In the analysis case, a=400mm,R1=200mm,H=100mm,R2=100mm,R=100mm,L=700mm。 Figure 2 shown.

[0042] The finite element analysis results show that:

[0043] (1) The stress concentration factor of the connection structure of the present invention is 1.20, while according to the specification, the stress concentration factors of the three existing structural forms are 1.52, 1.28, and 1.28 respectively. The fatigue life of the deck longitudinal of a bulk carrier is calculated by using the connection structure of the present invention. The fatigue life is at least 15% higher than that of the original structure. Therefore, the fatigue condition of the connection structure of the present invention is better than that of the existing structure.

[0044] (2) After further analysis, increasing the R value can effectively improve the fatigue condition at the inspection point. The larger the R value, the better the fatigue strength at the inspection point. Increasing the L value can also improve the fatigue condition.

[0045] The connection structure of the present invention can meet the requirements of ship design specifications regarding fatigue strength of the connection without thickening the corresponding components at the connection and without significantly increasing the size of the connection structure.

[0046] The connection structure of the present invention can not only improve the fatigue strength of the connection of the longitudinal bone ends and alleviate the stress concentration problem at the connection, but also effectively control the weight of steel materials and reduce construction costs.

[0047] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A connection structure for the ends of longitudinal frames of a bulk carrier, comprising connection plates respectively fixed to the deck longitudinals and transverse strong frames; the web of the transverse strong frame is perpendicular to the deck longitudinals, and the face plate of the transverse strong frame is parallel to the deck longitudinals; characterized in that: The connecting plate includes a plate body and a toe end, the toe end is connected to the plate body, the free edge of the plate body includes a first plate body edge and a second plate body edge connected in sequence, and the free edge of the toe end includes a first toe end edge, a second toe end edge, a third toe end edge and a fourth toe end edge connected in sequence; the first toe end edge is connected to the second plate body edge; the first plate body edge is a straight line distributed obliquely upward, and the second plate body edge is an inwardly concave arc; the first toe end edge is a straight line parallel to the deck longitudinal bone; the fourth toe end edge is a straight line perpendicular to the deck longitudinal bone, and the fourth toe end edge is connected to the deck longitudinal bone; the height of the fourth toe end edge is less than or equal to 15 mm; the second toe end edge is a convex arc, and the third toe end edge is a concave arc. The plate body also includes a first fixed edge, which is fixed to the web of the transverse strong frame; the distance from the first fixed edge to the fourth toe end edge is L, and the value range of L is 400mm≤L≤1000mm; the height from the first toe end edge to the deck longitudinal bone is H, and the value range of H is 100mm≤H≤200mm; the arc radius of the second toe end edge is R2, and the value range of R2 is 50mm≤R2≤200mm; the arc radius of the third toe end edge is R, and the value range of R is 100mm≤R≤300mm; the plate body and the toe end are integrally formed; the plate body also includes a second fixed edge, and the second fixed edge is fixedly connected to the deck longitudinal bone.

2. The connection structure of the longitudinal frame ends of a bulk carrier according to claim 1, characterized in that: The second fixed edge is perpendicular to the first fixed edge.

3. The connection structure of the ends of the longitudinal frames of a bulk carrier according to claim 2, characterized in that: The board body also includes a third fixed edge, which is fixed to the panel of the transverse strong frame.

4. The connection structure of the ends of the longitudinal frames of a bulk carrier according to claim 3, characterized in that: The toe end also includes a fourth fixed edge, which is fixed to the deck longitudinal bone.

5. The connection structure of the ends of the longitudinal frames of a bulk carrier according to claim 4, characterized in that: The fourth fixed edge is perpendicular to the fourth toe-end edge.

6. The connection structure of the ends of the longitudinal frames of a bulk carrier according to claim 5, characterized in that: The second fixed side and the fourth fixed side are located on the same straight line.

7. The connection structure of the ends of the longitudinal frames of a bulk carrier according to claim 1, characterized in that: The fourth toe end edge is parallel to the first fixed edge.

8. The connection structure of the ends of the longitudinal frames of a bulk carrier according to claim 1, characterized in that: The connection between the connecting plate and the transverse stiffener, and between the connecting plate and the deck longitudinal bone are all welded.

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