WO2021061059A1

WO2021061059A1 - A profile (bulb flat) developed for the shipbuilding industry and all structural constructions

Info

Publication number: WO2021061059A1
Application number: PCT/TR2019/050908
Authority: WO
Inventors: Ahmet TASDEMIR; Serkan Nohut; Mehmet AKMAN
Original assignee: T.C. Piri Reis Universitesi
Priority date: 2019-09-27
Filing date: 2019-10-28
Publication date: 2021-04-01
Also published as: KR20220066960A; CN114423535A; EP4034315A1; JP2023508813A

Abstract

The invention relates to the profiles used mostly in the shipbuilding and aircraft industry and in all structure constructions. The two-side-symmetrical bulbed profile has been developed by inspiring from a cross-sectional area and/or cross-sectional weight as existing profiles and bone formation in living organisms. The dimensional ranges of the profile are, b=80-450 mm, c=18-35 mm, t=3-20 mm, r= 4-20 mm, r1=1-10 mm, r2=1-10 mm, r3=1-5 mm and x=20-80 mm.

Description

A Profile (Bulb Flat) Developed for the Shipbuilding Industry and All

Structural Constructions

Technical Field

The invention relates to profiles used in shipbuilding industry and all structural constructions.

Prior Art

Ships and aircrafts are subjected to various internal and external loads during their movements. These loads, which directly affect the stress and deformation of the vehicles in the body structure, can be static and/or dynamic. In practice, the bodies of these vehicles are designed to have the strength to withstand these loads in order to maintain their structural integrity. Today, the bodies of these vehicles are formed from sheet metal and different profiles. One of the most widely used profiles in shipbuilding indusrty is the bulb profiles (Bulb Flat Stiffeners). Such profiles are used in the ship industry as an altxrnative to brackets, flats and other profiles. Similar profiles, which are frequently used in shipbuilding, have been strengthened by the bulb on the edge. The cross section is similar to the letter "P". The weight of the profiles used in ships constitutes approximately 8-10% of the total weight. These profiles directly affect the construction, the structural strength of the ship, the service life and the cost of production.

Purpose of the invention

The purpose of the invention is to reduce the stresses and deformation of the ship and aircraft hull or other structures with the developed profile. Another purpose of the invention is; to increase the life of ships and aircrafts or other constructions.

Another purpose of the invention is; to achieve a more robust and lighter ship and aircraft or construction.

Another purpose of the invention is; to achieve a ship and aircraft or construction with reduced production costs.

The profile developed to realize the mentioned objectives, have been inspired from a cross-sectional area and/or cross-sectional weight as existing profiles and bone formation in living organisms. The dimensional ranges of the profile are, b=80-450 mm, c=18-35 mm, t= 3-20 mm, r= 4-20 mm, r₁=1-10 mm, r₂=1-10 mm, r₃=l-5 mm and x =20-80 mm.

Description of the Figures

Figure-1 is the cross-sectional view of the profile (1). Figure-2 is the detailed view of the profile (1). Figure-3 is the detailed view of the profile (1). Figure-4 is the detailed view of the profile (1). Figure-5 is the perspective view of the profile (1).

The main parts represented in the figures are given as numbers and names below.

(1) Profile

The symbols in the figures are given as names and explanations below. b : Profile Height c : Half width t : Thickness r : Radius n : Radius r₁ : Radius r₃ : Radius x : Distance to the center axis

L : Length

Detailed Description of the Invention

The invention relates to the profiles (bulb flats) used mostly in the shipbuilding industry, aircraft industry and in all structure constructions.

Mentioned profile developed from the bone structure of living organisms and the cross-sectional area and/or cross-sectional weight of the existing profiles. As a result of the development, the moment of inertia of the profile is increased.

The invention has a symmetrical shape with bulbs on both sides, unlike some asymmetric profiles.

Long bones found in humans generally consist of bone head (tip) and bone body. The swollen portion at both ends of the long bone is called the bone tip (head). Humans have a robust skeletal system due to the structure of these bones.

As a result of the preliminary theoretical and numerical calculations, it has been found that the profile has 3 to 7 percent higher moment of inertia than the other profiles. Thus, the invented profile has less deformation and tension. Furthermore, by using the same weight material, the invented profile (1) provides more durable body structure. In addition, as the new profile structure will reduce the stresses and deformation occurring in the hull, a longer ship with a longer life can be obtained. The measurement ranges of the profile (1) are shown in Table 1. The value “x” in the two-dimensional drawing given in Figure- 1 indicates the distance of the center of the elliptical geometry at the top of the profile from the center of the area to the y-axis. The angle a = 30 degrees shown in Figure-1 is a constant value for all dimensions of the profile.

The dimensions of the profile (1) can take different values from the determined limits given in the Table 1. Dimensions taken in the preliminary study b = 140 mm, c = 19 mm, t = 8.24 mm, r = 5.50 mm, r₁ = 5 mm, n= 5 mm, r₃ = 2.5 mm and x = 60 mm.

The profile (1) is developed from the cross-sectional area and/or cross- sectional weight of the existing profiles and the bone structure of living organisms. Finally, it is aimed to increase the moment of inertia of the profile. Basically, the aim is to increase the moment of inertia around the neutral axis of the profile, thereby reducing the stresses in the profile.

The bending stress in the profile is calculated as follows.

Where sb is the bending stress in Pascal, M is the bending moment in the profile, y is the vertical distance from the neutral axis, and I is the moment of inertia around the neutral axis in the order of m⁴. Since the moment of inertia is fourth order, the increase in this parameter significantly reduces the bending stress. In the context of the development of the profile (1), the moment of inertia about the neutral axis is increased.

For the analysis of the profile (1) such as strength and deformation, different loading and boundary conditions were used within the scope of preliminary theoretical and numerical calculations. Finite Element Method (FEM) was used for numerical analysis of three-dimensional solid model.

By means of finite element method, profile (1) was subjected to built-in loading and two-dimensional loading tests. The tests and the data obtained are as follows. a) Fixed Constrained Boundary Condition, One-Dimensional Loading Test

Numerical calculations were made by using finite element method in order to examine the stress and deformation behavior on profile (1). The data used in the calculations for the fixed loading are as in Table-2.

b) Fixed Constrained Boundary Condition, Two-Dimensional Loading Test

Numerical calculations were made by using finite element method in order to examine the stress and deformation behavior on profile (1). The data used in the calculations for the fixed loading are as in Table-3.

The moment of inertia about the x-axis of the profile (1) is increased by about 3 percent and the moment of inertia about the y axis is increased by 70 percent. As a result of numerical calculations, the panel built with the invented profile (1) has 9% less tension compared to the panel built with the existing profiles. In addition, 11% less deformation was achieved in the profile (1) in comparison with the existing profiles in the one-sided fixed state.

Claims

C LA I M S

1. A profile (bulb flat) used in shipbuilding industry and in all constructions characterized in that;

- it has a two-side-symmetrical bulbed profile which have been developed by inspiring from a cross-sectional area and/or cross-sectional weight of existing profiles and bone formation in living organisms,

- the dimensional ranges of the profile are, b=80-450 mm, c=18-35 mm, t= 3-20 mm, r= 4-20 mm, r₁=l-10 mm, r₂=l-10 mm, r₃=1-5 mm and x =20-80 mm.

2. A profile (bulb flat) mentioned in Claim 1, characterized in that; in an alternative application of the invention, the profile dimensions are b = 140 mm, c = 19 mm, t = 8.24 mm, r = 5.50 mm, r₁ = 5 mm, r₂ = 5 mm, r₃ = 2.5 mm and x = 60 mm.

7