RU2682385C1 - Ship hull - Google Patents

Abstract

FIELD: shipbuilding.SUBSTANCE: invention relates to the field of shipbuilding, in particular to the design of ship hulls. Hull is an impermeable shell, formed from the outer skin and beams of the set. Bow end of the ship is equipped with a lower deck, streamlined, and an upper deck, made flat. Upper deck is divided into separate parts along the length of the ship. Each part of the flat deck is composed of length-oriented and pivotally connected sections and is equipped with a drum for placing/removing sections. Upper part of the side overlap in the bow end is made in the form of separate sections. Each section is pivotally connected at one end to the side overlap, and the other end is provided with an elastic element for the possibility of deviation from the equilibrium position.EFFECT: invention increases the safety of navigation, eliminating the catastrophic decrease in the stability of the ship and the destruction of its hull during the capture wave of the bow end.1 cl, 4 dwg

Description

The invention relates to the field of shipbuilding, in particular to the design of hulls.

A known design of the front part of a displacement type vessel (RF Patent for invention No. 2374120, IPC ВВВ 1/06, published on November 27, 2009) with transverse symmetry with respect to the central axis, with the hull forming lines increasing in width from the baseline. The bottom is flat or has a pitch and goes into the bottom with a given radius of the bottom. From the bottom to a predetermined height, the generatrix lines are slightly inclined outward. At the level of the deck of the tank, the shape of the outward sloping line stops and passes upward in the form of a curved line back in the direction of the central axis.

This design has the following disadvantages:

- the ship has a large windage;

- the wheelhouse is removed from the engine room, which makes it difficult to lay cable routes;

- poor habitability;

- shock waves can knock out windows in the wheelhouse and lead to damage to navigation equipment;

- at a high wave height, they can overlap through the superstructure, while the flat deck surfaces will contribute to the capture of the bow of the vessel by the wave [Burakovsky EP, Burakovsky PE Some problems of ensuring the general strength of ships in emergency situations // Transactions of the Krylov State Scientific Center. - Vol. 82 (366), 2014. - S. 21-30];

- poor germination per wave, because due to the slenderness of the waterline, the ship crashes into a wave, and it twists above the bow and to the side, as a result of which the bow of the ship can be captured by the wave, which will lead to the death of the ship.

Known hull with obstruction and reverse inclination of the stem (US 6601529, B63B 3/00, publ. 05.08.2003).

The disadvantage of this design is the low stability of the vessel, which can lead to capsizing and the death of the crew. This is due to the reduced waterline area compared to the traditional design, especially when passing wave crests, as well as to the low values of the restoring moment acting on the vessel during its heeling, which is due to the small volume of the vessel immersed in water during inclination.

The hull of the vessel, which is an impenetrable shell consisting of thin sheets, which are supported by beams made of rolled or composite welded sections (Barabanov N.V. Design of the hull of marine vessels. L., Shipbuilding, 1981. - 552 s), was adopted as the closest analogue. ., p. 9-11, figure 1).

This design has a significant drawback consisting in the possibility of capturing the bow of the nose by the wave, which is due to the presence of flat deck surfaces and the superstructure of the tank, as a result of which a metacentric height may fall and the vessel topple over or destruction of its hull [Burakovsky EP, Burakovsky P.E. Some problems of ensuring the general strength of ships in emergency situations // Transactions of the Krylov State Scientific Center. - Vol. 82 (366), 2014. - S. 21-30]. Capture of the nasal tip by a wave means that when the deck is flooded heavily, it operates in a submerged position as a wing streamlined by a liquid stream, as a result of which pressure forces arise on flat surfaces, which is determined by the angle of attack and the speed of the incoming liquid. This flow is unstable, as a result of which the resultant can at any moment move away from the diametrical plane and cause a strong roll or tipping of the vessel, as well as the destruction of its hull. Under the action of the resultant hydrodynamic forces, the trim of the vessel increases, while there is a sharp decrease in the transverse metacentric height, which contributes to the capsizing of the vessel.

The invention solves the problem of improving the safety of navigation, excluding a catastrophic decrease in the stability of the vessel and the destruction of its hull when a nasal tip is captured by a wave due to the ability to improve the flow around the nasal tip in critical situations and, as a result, reduce the hydrodynamic force acting on the bow of the ship.

To solve the problem in the hull, made in the form of an impenetrable shell formed from the outer skin and set beams, it is proposed to equip the bow tip with a lower deck made streamlined and an upper deck made flat, divided into separate parts along the length of the vessel. It is proposed that each part of the flat deck be composed of sections oriented along the length of the vessel and articulated sections and equipped with a drum for laying / removing sections. In addition, the upper part of the side overlap in the nasal tip is proposed to be made in the form of separate sections, while each section is pivotally connected at one end to the side overlap, and the second end is provided with an elastic element to allow deviation from the equilibrium position.

In the proposed technical solution, when there is a danger of wave entrapment of the bow of the vessel, the upper flat section deck is wound on drums, as a result of which, when the bow tip is immersed in water, the fluid flow acts on the lower deck of the streamlined shape, and, deflecting the articulated sections of the side cover, drains from it , which contributes to the improvement of the flow around the hull of the vessel and the reduction of the loads acting on it, which eliminates the capsizing of the vessel and the destruction of its hull.

The attached graphic materials show:

in FIG. 1 is a top view of the hull in the area of the bow;

in FIG. 2 is a section AA in FIG. one;

in FIG. 3 is a section AA in FIG. 1 with articulated sections of the side overlap deviated from the equilibrium position;

in FIG. 4 - node I in FIG. 3.

The following notations are used on graphic materials:

1 - upper flat sectional deck;

2 - lower streamlined deck;

3 - drum;

4 - beams;

5 - deck section;

6 - deck hinge;

7 - section of the side overlap articulated;

8 - onboard hinge;

9 - an elastic element;

10 - stiffener of the deck section;

b ₁ - the width of the sections of the deck, forming when winding on the drum the first layer, mm;

b ₂ - the width of the sections of the deck, forming when winding on a drum a second layer, mm;

b _1,2 - the width of the deck section on which the transition from the first layer to the second, mm;

L is the length of the face of the drum, mm

The hull structure consists of outer skin and set beams forming a streamlined lower deck 2 and an upper flat section deck 1, consisting of deck sections 5 supported by stiffeners 10 connected by deck hinges 6 and lying on beams 4. In the area of the ship’s diametrical plane, drums 3 to which adjoining sections 5 of the deck are attached. The upper part of the side overlap in the nasal extremity is made in the form of separate sections 7 mounted on hinges 8 and provided with elastic elements 9.

The hull operates as follows. When the vessel is moving in strong oncoming waves, the bow tip may periodically immerse in water, which leads to the appearance of a complex mode of flow around the deck. Under such conditions, significant loads may occur, acting on the hull of the vessel, caused by the flow around the submerged deck, which can be considered as a wing of complex shape, located at an angle of attack to the incoming liquid flow. Under the influence of hydrodynamic force, the trim of the vessel will increase, and its stability parameters will decrease sharply. In addition, there is an increase in stresses from the total bend, which can lead to the destruction of the hull [Burakovsky EP, Burakovsky PE Some problems of ensuring the overall strength of ships in emergency situations // Transactions of the Krylov State Scientific Center - Issue. 82 (366), 2014 - S. 21-30].

In the proposed design, in a storm, when there is a danger of a wave capturing the bow of the vessel, the upper flat section deck 1 is wound onto the drums 3. As a result, when the bow tip is immersed in water, a streamlined shape will flow around the lower deck 2, which will result in to reduce hydrodynamic loads on the deck of the vessel in its bow tip (Fig. 1, Fig. 2). In this case, the articulated sections 7 of the side overlap will deviate from the equilibrium position (Fig. 3), and water will drain from the streamlined lower deck 2. To ensure smooth winding on the drums 3 of the upper flat sectional deck 1, it is divided into parts along the length of the vessel, and the width of the vessel is made up of 6 sections 5 of the deck connected by deck hinges. Their width is determined by the diameter of the drum 3, its shape, the thickness of the casing, the height of the stiffening ribs 10 of the deck section, as well as the serial number of the deck section 5, counted from the deck section 5 closest to the drum 3. To give rigidity to the design of the upper flat sectional deck 1 of section 5, the decks are equipped with stiffening ribs 10 of the deck section, and beams 4 are made in the form of double beams, the gap between which corresponds to the thickness of the stiffening ribs 10 of the deck section. In the expanded state of the upper flat sectional deck 1, the stiffening ribs 10 of the deck section can be fastened to beams 4. In FIG. 4 shows a hexagonal drum 3 (the number of faces N = 6), in this case, when winding the upper flat section deck 1, in each layer of deck sections 5 laid on drum 3 there should be N-1 = 5 identical sections, and one different in length, used to go to the next level. Therefore, the width of the first five sections 5 of the deck closest to the drum 3 should be taken equal to the length of its face, i.e. b ₁ = L. The width b ₂ (mm) of five identical sections 5 of the deck, forming a second layer when winding on the drum 3, should be determined by the expression

Where

h is the height of the stiffening ribs 10 of the deck section, mm;

t is the thickness of the skin section 5 of the deck, mm

So, with the length of the drum face L = 600 mm, we have: b ₁ = 600 mm, b ₂ = 669.3 mm. Similarly, the width b _n (mm) of the deck sections 5 can be determined, forming a layer with the number n when winding on the drum

Where

b _n-1 - the width of the sections 5 of the deck, forming when winding on a drum layer with the number n-1, mm

In the General case, when the number of faces of the drum 3 is N, the width of the sections 5 of the deck should be determined from the expression

Where

b _n - width of sections 5 of the deck, forming when winding on the drum layer with the number n, mm;

b _n-1 - the width of the sections 5 of the deck, forming when winding on a drum layer with the number n-1, mm;

h is the height of the stiffening ribs 10 of the deck section, mm;

t is the thickness of the skin of the deck section 5, mm;

N is the number of faces of the drum.

The width of the deck section 5, on which the transition to the next level is carried out when winding the upper flat sectional deck 1 onto the drum 3, is determined from the expression

Where

b _n - width of sections 5 of the deck, forming when winding on the drum layer with the number n, mm;

b _n-1 - the width of the sections 5 of the deck, forming when winding on a drum layer with the number n-1, mm;

b _{n-1, n} - width of section 5 of the deck, on which the transition from layer with number n-1 to layer with number n, mm;

N is the number of faces of the drum.

So, in the above example, a hexagonal drum in the length of the face L = 600 mm b _1,2 = 637,3 mm

In the absence of a stream of liquid flowing around the lower deck 2, the articulated sections 7 of the side overlap are pressed against the hull of the vessel under the action of the elastic elements 9. When the ship rolls, the articulated sections 7 of the side overlap will be additionally pressed against the hull by the pressure of the outside water, preventing it from entering the space between the streamlined lower deck 2 and the upper flat sectional deck 1. Thus, in the case of the proposed design, the ship will have the entire area of the waterline and, accordingly, have high lateral stability.

The force acting on the bow tip of the structure of the closest analogue (or the proposed structure with the upper flat section deck 1 in the expanded state) and the proposed structure after winding the upper flat section deck 1 on the drums 3 can be estimated using (Kuhling X. Physics reference: Per .with. German 2nd ed. - M .: Mir, 1985. - 520 p.). So, a force F (N) acts on a body in a fluid flow

where C is a coefficient depending on the shape of the body, the Reynolds number (for the plate C _layer = 1.11, for the streamlined body C _obt = 0.4);

S is the area of the largest section of the body in a plane perpendicular to the direction of flow, m ² ;

ρ is the density of the liquid, kg / m ³ ;

V is the velocity of the fluid flow incident on the body, m / s.

Since for the design of the closest analogue (or the proposed design with the upper flat sectional deck 1 in the unfolded state) and the proposed design after winding the upper flat sectional deck 1 on the drums 3, the parameters S, V, ρ are equal, the ratio of the forces acting on them during the flow nasal extremity, equal to the ratio of the coefficients C _layer and C _obt , i.e.

where F _b.a. - the force acting on the structure of the closest analogue (or the proposed structure with the upper flat sectional deck 1 in the unfolded state) when flowing around the bow tip;

F _n.k. - the force acting on the proposed design after winding the upper flat sectional deck 1 on the drums 3 when flowing around the bow tip.

Thus, the proposed design allows almost 3 times to reduce the hydrodynamic force acting on the bow of the vessel during its flow.

To identify a dangerous situation in which there is a possibility of a wave capturing the bow of the ship, and, accordingly, the need to wind the upper flat section deck 1 on the drums 3, approaches to control the dynamics of the ship described in [Burakovsky P.E., Nechaev Yu .AND. The construction of an algorithm for monitoring the situation of wave capture of the bow of the ship by the methods of the modern theory of disasters // Bulletin of KSTU. - Kaliningrad: FSBEI HPE “KSTU”, 2015. - No. 37. - from. 178-185]. In this case, the command to wind the upper flat sectional deck 1 onto the drums 3 can be given both by the skipper and the onboard intelligent system in automatic mode.

Thus, the proposed design, in contrast to the closest analogue, eliminates the loss of stability and the destruction of the hull when moving oncoming waves in stormy conditions, improving the flow around the bow in critical situations, which improves navigation safety.

Claims (1)

The hull of the vessel, made in the form of an impermeable shell formed from the outer skin and set beams, characterized in that the bow is equipped with a lower deck, streamlined, and an upper deck made flat, divided into separate parts along the length of the vessel, each part of a flat deck composed of sections oriented along the length of the vessel and articulated connected and provided with a drum for laying / removing sections, in addition, the upper part of the side overlap in the bow is made as separate sections, where each section is pivotally connected at one end to a ceiling board, a second end provided with a resilient element for the possibility of deviation from the equilibrium position.

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