Shaft-propulsion polar vessel with stern-ramming icebreaking capability

Abstract

This application belongs to the field of marine technology and discloses a shaft propeller-driven polar vessel with stern-mounted impact-type icebreaking function. The vessel includes a hull and a rudder. The hull includes a stern and an icebreaking component. The upper end of the icebreaking structure of the icebreaking component is fixed to the bottom of the stern, and the lower end of the icebreaking structure is connected to a support structure. Each support structure is rotatably connected to a rudder. The distance between the rotation axis of the rudder and the stern endpoint of the design waterline is 0.3B to 0.4B, where B is the width of the hull. The design waterline intersects with the icebreaking ridge to ensure the rudder is sufficiently far from the ice layer, reducing the probability of collision between the rudder and the ice layer or ice fragments. The end of the icebreaking structure near the stern has a straight-lined icebreaking ridge. The angle between the icebreaking ridge and the horizontal direction is 25° to 35°, making the icebreaking ridge as close to the horizontal as possible to the ice layer. This allows the icebreaking ridge to perform impact-type icebreaking. Compared to compression-type icebreaking, impact-type icebreaking reduces the power required for icebreaking and improves the icebreaking effect.

Description

Technical Field

[0001] This application relates to the field of ship technology, specifically to a shaft propeller-driven polar vessel with stern-mounted ramming icebreaking function. Background Technology

[0002] Polar vessels are specialized ships designed for extreme environments such as low temperatures, thick ice, and ice ridges in polar regions. They must balance icebreaking capabilities, low-temperature weather resistance, and propulsion reliability. Common polar vessels include podded propulsion polar vessels and propeller-driven polar vessels. For podded propulsion polar vessels, since the thrust of the pods is almost unaffected when sailing stern, and the vessel's maneuverability is easily maintained, podded propulsion polar vessels naturally possess bidirectional icebreaking capabilities, and their stern-wise icebreaking capability is even stronger than their bow-wise icebreaking capability. However, for propeller-driven polar vessels, the thrust of the fixed-pitch propeller inevitably decreases significantly when sailing stern, and the vessel's maneuverability also decreases. Therefore, propeller-driven polar vessels have poor stern-wise icebreaking capabilities, posing navigational risks.

[0003] Patent CN201410632375.X discloses a ducktail-type stern icebreaking structure (actually a propeller-driven polar vessel), including a stern, rudder, ducktail, false rudder, and ice blades. When sailing stern-wise, the ducktail crushes floating ice or ice layers on the water surface, while the ice blades and false rudder cut through ice fragments heading towards the rudder, increasing the vessel's maneuverability in icy areas. Patent application KR20120133964A discloses an icebreaking vessel (actually a podded propulsion polar vessel), including a stern, ice-crushing structures, and a podded propulsion device. Two ice-crushing structures are spaced apart at the stern, and are used for icebreaking when sailing stern-wise.

[0004] Both patent CN201410632375.X and patent application KR20120133964A primarily employ compression-based ice-breaking structures. However, for thicker ice layers, the compressive strength of ice is significantly higher than its flexural strength, and the compressive strength of sea ice is generally 2 to 6 times its flexural strength. This means that the compression-based ice-breaking mode requires more power.

[0005] Therefore, there is an urgent need to provide a shaft propeller-driven polar vessel with stern-mounted ramming icebreaking capability to solve the above problems. Summary of the Invention

[0006] The purpose of this application is to solve or at least alleviate some or all of the aforementioned problems. Therefore, the purpose of this application is to provide a shaft-propeller-driven polar vessel with stern-mounted ram-type icebreaking capability, which not only improves stern-mounted icebreaking ability but also protects the rudder, thereby enhancing the safety of polar navigation.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] A shaft-propeller-driven polar vessel with stern-ramming icebreaking capability includes a hull and a rudder, wherein the hull comprises:

[0009] Stern section;

[0010] An icebreaker includes an icebreaking structure and a support structure. The upper end of the icebreaking structure is fixed to the bottom of the stern, and the lower end of the icebreaking structure is connected to the support structure. The end of the icebreaking structure near the stern has a straight icebreaking ridge, and the angle γ between the icebreaking ridge and the horizontal direction is in the range of 25° to 35°.

[0011] Each of the aforementioned support structures is rotatably connected to the rudder, and the distance L1 between the rotation axis of each rudder and the stern end of the design waterline ranges from 0.3B to 0.4B, and the design waterline intersects with the icebreaker, where B is the width dimension of the hull.

[0012] As an optional embodiment of the propeller-driven polar vessel with stern-ramming icebreaking function, the icebreaking structure includes a first outer contour surface and a second outer contour surface. The stern end of the first outer contour surface and the stern end of the second outer contour surface meet at the icebreaking ridge, and the bow end of the first outer contour surface and the bow end of the second outer contour surface are smoothly connected.

[0013] As an optional embodiment of the propeller-driven polar vessel with stern-ramming icebreaking function, the first outer contour surfaces of the two icebreakers are arranged opposite each other. The angle between the tangent of the first outer contour surface at the farthest vertical position from the rotation axis of the rudder and the rotation axis is α, and the angle between the tangent of the second outer contour surface at the farthest vertical position from the rotation axis of the rudder and the rotation axis is β, wherein α is less than β.

[0014] As an alternative to the aforementioned propeller-driven polar vessel with stern-ramming icebreaking function, the angle α between the tangent of the first outer contour surface at the farthest vertical position from the rotation axis of the rudder and the rotation axis ranges from 20° to 30°.

[0015] And / or, the angle β between the tangent plane of the second outer contour surface at the farthest vertical position from the rotation axis of the rudder and the rotation axis ranges from 35° to 45°.

[0016] As an alternative to the aforementioned propeller-driven polar vessel with stern-ramming icebreaking capability, the sum of α and β ranges from 55° to 65°.

[0017] As an alternative to the aforementioned propeller-driven polar vessel with stern-ramming icebreaking function, the distance between the first outer contour surface and the second outer contour surface gradually increases and then decreases from the bow to the stern.

[0018] As an alternative to the aforementioned propeller-driven polar vessel with stern-ramming icebreaking function, the cross-sectional shape of the icebreaking structure is teardrop-shaped, and the tip of the teardrop shape is located at the icebreaking ridge.

[0019] As an optional embodiment of the shaft propeller-driven polar vessel with stern-ramming icebreaking function, the two icebreakers are fixed symmetrically to the bottom of the stern with the centerline in the width direction as the axis. The support structure of each icebreaker is rotatably connected to the rudder, and the distance L2 between the rotation axes of the two rudders ranges from 0.5B to 0.7B.

[0020] As an optional embodiment of the shaft propeller-driven polar vessel with stern-ramming icebreaking function, the lower end face of the icebreaking structure is a plane, the upper end face of the rudder is a plane, and the upper end face of the rudder is clearance-fitted with the lower end face of the icebreaking structure.

[0021] As an alternative to the aforementioned propeller-driven polar vessel with stern-ramming icebreaking function, the support structure includes a connecting part and a supporting part. The connecting part is fixedly connected to the lower end face of the icebreaking structure. At least two supporting parts are connected to the connecting part in parallel and spaced apart along the ship's height direction. Each supporting part is provided with a first shaft hole. The rudder is provided with a second shaft hole that communicates with the first shaft hole. The rudder is rotatably mounted on the support structure by means of a rotating shaft passing through the second shaft hole and the first shaft hole.

[0022] The beneficial effects of this application are as follows:

[0023] The propeller-driven polar vessel provided in this application includes a hull and a rudder. The hull includes a stern and icebreakers. The stern has an axisymmetric structure centered on the centerline in the beam direction. Two icebreakers are symmetrically fixed to the bottom of the stern about the centerline in the beam direction. Each icebreaker includes an icebreaking structure and a support structure. The upper end of the icebreaking structure is fixed to the bottom of the stern, and the lower end of the icebreaking structure is connected to the support structure. Each support structure is rotatably connected to a rudder. The distance L1 between the rotation axis of the rudder and the stern endpoint of the design waterline ranges from 0.3B to 0.4B. Furthermore, the design incorporates a waterline intersecting with the icebreaking ridge to keep the rudder sufficiently away from the ice layer, reducing the probability of collisions between the rudder and the ice or ice fragments. In addition, the icebreaking structure has a straight-lined icebreaking ridge extending from the stern, with an angle γ between the icebreaking ridge and the horizontal direction ranging from 25° to 35°. This allows the icebreaking ridge to be as close to the horizontal as possible to the ice layer, enabling it to break the ice by impact rather than by compression. Compared to compression icebreaking, impact icebreaking reduces the power required for icebreaking and avoids kinetic energy loss or excessive impact load when the ship is breaking ice from the stern. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a shaft propeller-driven polar vessel provided in an embodiment of this application.

[0025] Figure 2 This is a longitudinal cross-sectional view of the icebreaker and rudder in the direction of ship width at the axis of rotation, provided in the embodiments of this application, in their disassembled state.

[0026] Figure 3 This is a longitudinal cross-sectional view of the icebreaker provided in this application at its widest position in the beam direction along the length direction.

[0027] Figure 4 yes Figure 3 A magnified view of a portion of the image.

[0028] Figure 5 This is a schematic cross-sectional view of the ice-breaking structure provided in the embodiments of this application at different heights.

[0029] Figure 6 This is a finite element model diagram of a shaft propeller-driven polar vessel provided in an embodiment of this application.

[0030] Figure 7 This is a finite element model of a polar vessel, as shown in Comparative Scale A.

[0031] Figure 8 This is a finite element model of a polar vessel, as shown in Comparative B.

[0032] Figure 9 This is a finite element model diagram of the impact load plate position at the stern of a propeller-driven polar vessel provided in this application embodiment.

[0033] Figure 10 This is a finite element model diagram of the impact load plate at the stern of a polar vessel, as shown in Comparative A.

[0034] Figure 11 This is a finite element model diagram of the impact load plate at the stern of a polar vessel, as shown in Comparative Scale B.

[0035] Figure 12 This is a schematic diagram of the boundary conditions for the entire ship.

[0036] Figure 13 This is the VON-MIESE stress result of the stern of a ship under working condition 1 provided in the embodiment of this application.

[0037] Figure 14 The VON-MIESE stress results of the stern of the ship under working condition two are provided in the embodiments of this application.

[0038] Figure 15 The VON-MIESE stress results of the stern of the ship under three working conditions are provided in the embodiments of this application.

[0039] Figure 16 This is the VON-MIESE stress result of the stern of the ship under four working conditions provided in the embodiments of this application.

[0040] Figure 17 This is the VON-MIESE stress result of the stern of the ship in operating condition 1 of Comparative Example A.

[0041] Figure 18 The results show the VON-MIESE stress at the stern of the ship in Comparative Example A under Working Condition 2.

[0042] Figure 19 The results show the VON-MIESE stress at the stern of the ship in Comparative Example A under operating condition 3.

[0043] Figure 20 The results show the VON-MIESE stress at the stern of the ship in Comparative Example A under operating conditions at four locations.

[0044] Figure 21 The results show the VON-MIESE stress at the stern of the ship in Comparative Example A under operating condition 5.

[0045] Figure 22 The results show the VON-MIESE stress at the stern of the ship in Comparative Example A under operating condition six.

[0046] Figure 23 The results show the VON-MIESE stress at the stern of the ship in Comparative Example A under operating condition seven.

[0047] Figure 24This is the VON-MIESE stress result of the stern of the ship in operating condition one for Comparative Example B.

[0048] Figure 25 The results are VON-MIESE stresses of the stern of the ship in Comparative Example B under Working Condition 2.

[0049] Figure 26 The results are VON-MIESE stresses at the stern of the ship in Comparative Example B under operating condition three.

[0050] Figure 27 This is a schematic diagram of hull stress provided in an embodiment of this application.

[0051] Figure 28 This is a schematic diagram of the hull stress in Comparative Example B.

[0052] Figure 29 This is a schematic diagram of deck stress provided in an embodiment of this application.

[0053] Figure 30 This is a schematic diagram of deck stress in Comparative Example B.

[0054] In the picture:

[0055] 100. Hull; 200. Rudder; 201. Main body; 202. Connecting part; 2020. Second shaft hole; 300. Propeller;

[0056] 1. Stern section;

[0057] 2. Ice-breaking component; 21. Ice-breaking structure; 210. Third shaft hole; 211. Ice-breaking rib; 212. First outer contour surface; 213. Second outer contour surface; 22. Support structure; 221. Connecting part; 222. Supporting part; 2220. First shaft hole. Detailed Implementation

[0058] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0059] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0060] In the description of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0061] It is worth noting that the orientation or positional relationship indicated by "top", "bottom", "upper", "lower", "left", "right", "front", "rear" etc. in this application is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the purpose of simplifying the description of this application and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0062] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments.

[0063] like Figures 1 to 3 As shown, this application provides a shaft propeller-driven polar vessel, including a hull 100, a rudder 200 and a propeller 300. The rudder 200 is rotatably connected to the bottom of the hull 100 and is used to change the direction of the vessel when it is sailing. The propeller 300 is installed on the bottom of the hull 100 and is spaced apart from the rudder 200. The propeller 300 is used to provide the propulsion for the vessel when it is sailing.

[0064] The hull 100 includes a stern 1 and icebreakers 2. The stern 1 has an axisymmetric structure with the centerline in the width direction as the center. The two icebreakers 2 are symmetrically fixed to the bottom of the stern 1 with the centerline in the width direction as the center. Each icebreaker 2 includes an icebreaking structure 21 and a support structure 22. The upper end of the icebreaking structure 21 is fixed to the bottom of the stern 1, and the lower end of the icebreaking structure 21 is connected to the support structure 22. The end of the icebreaking structure 21 near the stern has a straight icebreaking ridge 211. The angle γ between the icebreaking ridge 211 and the horizontal direction is in the range of 25° to 35°, which allows the icebreaking ridge 211 to be as close to the horizontal as possible with the ice layer. This allows the icebreaking ridge 211 to perform impact-type icebreaking instead of compression-type icebreaking. Compared with compression-type icebreaking, impact-type icebreaking can reduce the power required for icebreaking and avoid kinetic energy loss or excessive impact load when the ship is breaking ice in the stern direction.

[0065] In some embodiments, the angle γ between the ice-breaking rib 211 and the horizontal direction ranges from 25° to 35°, such as 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, etc., and is not limited herein.

[0066] Each support structure 22 is rotatably connected to a rudder 200. The distance L1 between the rotation axis of each rudder 200 and the stern end of the design waterline ranges from 0.3B to 0.4B, for example, 0.3B, 0.31B, 0.32B, 0.33B, 0.34B, 0.35B, 0.36B, 0.37B, 0.38B, 0.39B, and 0.4B. The design waterline intersects with the icebreaker 211, where B is the width dimension of the hull 100. This arrangement keeps the rudder 200 away from the solid ice layer during icebreaking, preventing damage to the rudder 200 from the ice layer and ice fragments after icebreaking.

[0067] It should be noted that, theoretically, this design can basically prevent ice and ice fragments after ice breaking from contacting the rudder 200. However, in reality, there is a small probability that ice fragments in the seawater may come into contact with the rudder 200, but the ice fragments are not enough to cause damage to the rudder 200. Therefore, designing the distance between the rotation axis of the rudder 200 and the stern end of the design waterline to be 0.3B to 0.4B can effectively protect the rudder 200.

[0068] The distance L2 between the rotation axes of the two rudders 200 ranges from 0.5B to 0.7B. This arrangement ensures that the two rudders 200 have sufficient spacing in the width direction, and also ensures that the two icebreakers 2 have sufficient spacing in the width direction, so as to provide enough room for ice fragments to move between the two icebreakers 2 and prevent ice fragments from accumulating between the two icebreakers 2.

[0069] like Figures 4 to 5 and combined Figure 2 As shown, the icebreaking structure 21 includes a first outer contour surface 212 and a second outer contour surface 213. The stern end of the first outer contour surface 212 and the stern end of the second outer contour surface 213 meet at the icebreaking ridge 211. The bow end of the first outer contour surface 212 and the bow end of the second outer contour surface 213 are smoothly connected. This design makes the structure of the icebreaking structure 21, except for the icebreaking ridge 211, a curved surface. The contact area between the curved surface and the ice fragments is small, making it difficult for the ice fragments to form a stable attachment relationship with the curved surface, thus preventing the ice fragments from accumulating on the outer contour surface of the icebreaking structure 21.

[0070] During shipbuilding, the stern end of the first outer contour surface 212 of the icebreaking structure 21 and the stern end of the second outer contour surface 213 can be fixedly connected by welding. This not only ensures the connection strength between the first outer contour surface 212 and the second outer contour surface 213, but also facilitates the adjustment of the tilt angle of the icebreaking rib 211 during the welding process, ensuring that the tilt angle of the icebreaking rib 211 meets the design requirements.

[0071] The first outer contour surfaces 212 of the two icebreakers 2 are arranged opposite each other. The angle between the tangent plane of the first outer contour surface 212 at the farthest vertical position from the rotation axis of the rudder 200 and the rotation axis is α. The angle between the tangent plane of the second outer contour surface 213 at the farthest vertical position from the rotation axis of the rudder 200 and the rotation axis is β, where α is less than β. By making the inclination angle of the first outer contour surface 212 of the icebreaker 2 closer to the ship's center smaller than the inclination angle of the second outer contour surface 213 of the icebreaker 2 farther from the ship's center, on the one hand, the second outer contour surfaces 213 of the two icebreakers 2 have a guiding effect on the movement of the ice fragments at that position away from the hull 100, preventing the ice fragments from accumulating below the hull 100, and thus preventing the ice fragments from damaging the rudder 200 or the propeller 300; on the other hand, it can increase the distance between the two icebreakers 2 at the first outer contour surface 212, providing sufficient space for the ice fragments to move between the two icebreakers 2, and preventing the ice fragments from accumulating between the two icebreakers 2.

[0072] In some embodiments, the angle α between the tangent plane of the first outer contour surface 212 at the farthest vertical position from the rotation axis of the rudder 200 and the rotation axis ranges from 20° to 30°, such as 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, etc., and is not limited herein. The angle β between the tangent plane of the second outer contour surface 213 at the farthest vertical position from the rotation axis of the rudder 200 and the rotation axis ranges from 35° to 45°, such as 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°, etc., and is not limited herein.

[0073] In some embodiments, the sum of α and β ranges from 55° to 65°, such as 55°, 56°, 57°, 58°, 59°, 60°, 61°, 62°, 63°, 64°, 65°, etc., and is not limited herein.

[0074] In the icebreaking structure 21, the distance between the first outer contour surface 212 and the second outer contour surface 213 gradually increases and then decreases from the bow to the stern. Furthermore, the lower end face of the icebreaking structure 21 is teardrop-shaped, with the tip of the teardrop located in the bow direction, i.e., at the icebreaking ridge 211, and the rounded end located in the stern direction. This design guides the ice fragments around the icebreaking structure 21, giving them a tendency to move outwards from the hull 100, thereby avoiding or reducing the accumulation of ice fragments at the icebreaking structure 21.

[0075] The lower end face of the icebreaking structure 21 is flat, and the upper end face of the rudder 200 is flat, with a clearance fit between the upper end face of the rudder 200 and the lower end face of the icebreaking structure 21. This design ensures that the rudder 200 can rotate relative to the icebreaking structure 21 while preventing ice fragments and other debris from accumulating in the gap between the rudder 200 and the lower end face of the icebreaking structure 21, thus ensuring the normal operation of the rudder 200.

[0076] Regarding the assembly scheme between the rudder 200 and the support structure 22, the support structure 22 has a first shaft hole 2220, and the rudder 200 has a second shaft hole 2020 that communicates with the first shaft hole 2220. The rudder 200 is rotatably mounted on the support structure 22 by passing a rotating shaft through the second shaft hole 2020 and the first shaft hole 2220.

[0077] Furthermore, the lower end face of the icebreaking structure 21 is provided with a third shaft hole 210, which is connected to the first shaft hole 2220. The rotating shaft also passes through the third shaft hole 210 and is rotatably connected to the icebreaking structure 21. This arrangement allows the rudder 200 to rotate and cooperate with both the support structure 22 and the icebreaking structure 21 simultaneously via the rotating shaft, thereby improving the stability of the rudder 200.

[0078] The support structure 22 includes a connecting part 221 and a support part 222. The connecting part 221 is fixedly connected to the lower end face of the icebreaking structure 21. At least two support parts 222 are connected to the connecting part 221 in parallel along the ship height direction. Each support part 222 is provided with a first shaft hole 2220.

[0079] In some embodiments, there are two support portions 222, each of which has a first shaft hole 2220. The rudder 200 has two insertion portions 202 arranged parallel to each other along the ship's height direction. Each insertion portion 202 has a second shaft hole 2020. One insertion portion 202 is inserted into the gap between the support portion 222 and the icebreaking structure 21, and the other insertion portion 202 is inserted into the gap between the two support portions 222. The pivot passes through the second shaft hole 2020 of the insertion portion 202 and the first shaft hole 2220 of the support portion 222, so that the rudder 200 is rotatably mounted on the support structure 22.

[0080] Furthermore, the rudder 200 includes a main body 201 and a connecting part 202. The main body 201 is generally inverted L-shaped. Two connecting parts 202 are arranged vertically at intervals above the main body 201, with the lower connecting part 202 also spaced apart from the main body 201. One of the two support parts 222 is inserted into the gap between the two connecting parts 202, and the other support part 222 is inserted into the gap between the connecting part 202 and the main body 201. This arrangement not only allows the support structure 22 to fit tightly with the rudder 200, improving the stability of the rudder 200, but also allows for an increase in the size of the rudder 200 in both the length and height directions of the ship, thereby improving the navigation and steering capabilities of the rudder 200.

[0081] To better illustrate the ice-breaking effect of the ice-breaking component 2 provided in this application, which is superior to the ice-breaking effect of the ice-breaking structure provided by patent CN201410632375.X and patent application KR20120133964A, the following section will model the ice-breaking component provided in this application and the ice-breaking structure of patent CN201410632375.X and patent application KR20120133964A, and provide a detailed explanation through finite element stress analysis.

[0082] It should be noted that, in order to fairly compare the icebreaking effect and stress of the three schemes, the bow and internal structure of the three schemes are the same, only the icebreaking structure is different. Among them, patent CN201410632375.X is comparative example A, and patent application KR20120133964A is comparative example B.

[0083] The finite element model was established and calculated using the finite element software Patran (Fasttrack), and the results were post-processed using the Nastran program. Patran is a commonly used pre-processing software in the marine and aerospace fields, while Nastran is an analysis and processing program capable of load-force analysis. The finite element analysis steps are as follows:

[0084] 1) Hull modeling: such as Figures 6 to 8As shown, during the modeling process, all areas of the hull were modeled except for the superstructure and structures that do not significantly affect the calculation results (such as the rib end plates and rudder). The hull was simulated using a plate-beam composite model. The deck, outer plating, longitudinal and transverse bulkheads, platforms, and major supporting components (such as trusses) and web plates were all modeled using 2D plate elements (SHELL), while ribs, stiffeners, and panels were modeled using 1D beam elements (BEAM / BAR). The overall coordinate system of the finite element model was as follows: the positive X-axis was along the length of the ship towards the bow; the positive Y-axis was along the width of the ship towards the port side; and the positive Z-axis was upward along the height of the ship. The origin was located at FR0 (the intersection point of the cross section at rib 0 and the baseline). The mesh was generated according to the rib spacing and rib spacing, with an element size of approximately 700mm × 700mm.

[0085] 2) Material Properties: The hull structure is constructed using both ordinary and high-strength marine structural steel. For example, ordinary marine structural steel uses grades "A, B, D, and E"; high-strength marine structural steel uses grades "AH36, DH36, and EH3". The physical property parameters of the materials used in the calculations are as follows:

[0086] The elastic modulus E is 2.06 × 10⁻⁶. 11 N / m 2 ;

[0087] Poisson's ratio μ is 0.3;

[0088] The yield point s is 235MPa / 355MPa;

[0089] The density ρ is 7.85 t / m³. 3 .

[0090] 3) Load and Calculation Conditions: For fair comparison, the same speed, ice thickness, ice bending strength, and kinetic energy data were used in the calculations for all three, as shown in Table 1. It is worth mentioning that the ice width is different because the stern lines of the three are different. In order to ensure that the stern can contact the ice, different ice widths were used. Therefore, the ice load increases with the increase of the width.

[0091] Table 1 Analysis Data

[0092]

[0093] Ice loads were applied to the stern. Since the actual contact point between the ice and the stern may vary along the draft direction, different regions were divided for finite element analysis. Regarding the technical solution of this application's embodiments, such as... Figure 9 As shown, a total of 4 regions were divided, meaning 4 operating conditions were calculated. For comparative example scheme A, as follows... Figure 10As shown, the section is relatively long in the draft direction and is divided into 7 zones, meaning 7 operating conditions were calculated. For comparative example B, as... Figure 11 As shown, the area is relatively short in the draft direction, and it is divided into 3 regions, which means 3 working conditions were calculated.

[0094] When applying ice loads to the sterns of the three ship types under different working conditions, the corresponding ice loads were kept constant, and the surface pressure values ​​were adjusted according to the actual contact area. The resultant forces when applied to different areas using this method are shown in Tables 2, 3, and 4. It can be seen that the ice loads are roughly the same for the same ship type, and are not much different from the design ice loads of the sterns of each ship type in Table 1.

[0095] Table 2 Ice Load of Examples

[0096]

[0097] Table 3 Ice load in Comparative Example A

[0098]

[0099] Table 4 Ice Load of Comparative Example B

[0100]

[0101] 4) Boundary Conditions: The impact load acts on the stern of the hull. To minimize the impact of boundary conditions on the results, the boundaries should be as far away from the evaluation area as possible. Therefore, if... Figure 12 As shown, all three full-ship finite element models are located at the anti-collision bulkhead. The anti-collision bulkhead towards the center of the bow adopts a fixed boundary condition, constraining all six degrees of freedom of the dock unit node.

[0102] 5) Calculation results: such as Figures 13 to 16 As shown, this application's embodiments exhibit stress distribution diagrams under different working conditions. Figures 17 to 23 As shown, this is a stress distribution diagram under different working conditions in Comparative Example A. Figures 24 to 26 As shown, this is a stress distribution diagram under different working conditions in Comparative Example B.

[0103] The calculation results above show that the maximum VON-MISES stress in the Example, Comparative Example A, and Comparative Example B is 135 MPa (condition 4, see...). Figure 16 ), 527MPa (Operating Condition 7, see Figure 23 ) and 153MPa (condition 1, see Figure 24As the ice load area shifts downwards, the local stress in both the embodiment and Comparative Example A generally shows a gradual increasing trend, a phenomenon particularly pronounced in Comparative Example A. The maximum stress in Comparative Example A occurs at the corner where the small-sized ice blade connects to the appendage, indicating that the stern of Comparative Example A has an extremely high risk of structural failure during stern-to-stern navigation in actual ice conditions, and is unable to achieve the ramming icebreaking function of the embodiment. Therefore, the structural stress of the embodiment has a very significant advantage compared to the stern of Comparative Example A. The failure mode of the stern of Comparative Example A during icebreaking is mainly compressive failure. As mentioned earlier, the compressive strength of sea ice is 2 to 6 times its flexural strength, which results in the stress at the stern of Comparative Example A being much higher than the other two schemes, also implying significant drag. Furthermore, the stern of Comparative Example A may also face the risk of getting stuck in ice in actual ice conditions.

[0104] The stern of Comparative Example B is a conventional design often used in actual ships operating in ice-covered environments. This design utilizes the downward pressure exerted by the stern on the ice to cause bending failure, with very little ice compression failure. Therefore, Comparative Example B fully leverages the relatively low bending strength of ice, and the structural stress is not as high as in the embodiment. However, although the local stress at the stern is relatively low, according to Newton's third law, the ice will also exert a significant force on the stern in the vertical direction, thus generating a bending moment that has a substantial impact on the overall longitudinal strength of the ship.

[0105] Figure 27 and Figure 28 The figures show the hull stress diagrams for the embodiment and Comparative Example B, respectively, as indicated by the red line. In the embodiment, the stress gradient is sloping, indicating that the force transmission direction is inclined. In contrast, the stress gradient in Comparative Example B is vertical, indicating that the force transmission is almost vertically upward. Furthermore, the figures show that the bending moment generated by the ice load in the embodiment is small, resulting in lower stress near the stern hatch, approximately 149 MPa; while in Comparative Example B, the bending moment is larger, leading to a stress as high as 214 MPa near the stern hatch.

[0106] Figure 29 and Figure 30 The deck stress diagrams for the embodiment and Comparative Example B are shown below. It is clearer that the stress near the hatch in Comparative Example B is greater. Furthermore, the deck of the embodiment only shows a localized stress of 80 MPa, while the deck of Comparative Example B shows a stress of 100 MPa across almost the entire width, indicating that the bending moment generated by the ice load in Comparative Example B has a more significant impact on the overall longitudinal strength.

[0107] As can be seen from the above analysis, the local stress of the stern structure of the embodiment is significantly better than that of Comparative Example A and slightly better than that of Comparative Example B. Compared with Comparative Example B, the embodiment bears a smaller total longitudinal bending moment, and therefore the corresponding deck stress and stern hatch stress are also lower. In addition, it also has the characteristic of lower resistance during open water navigation.

[0108] In summary, the shaft-propeller-driven polar vessel with stern-ramming icebreaking capability provided in this application has the following advantages:

[0109] 1) The icebreaking ridge 211 of icebreaker 2 adopts a smaller inclination angle to achieve icebreaking primarily through impact, resulting in lower structural stress and less ice resistance compared to existing technologies that rely mainly on crushing. Furthermore, the design of the icebreaking ridge 211 also considers the feasibility of practical application to the ship type, avoiding an excessively small angle. This design reduces the bending moment caused by ice loads, minimizes the impact on overall longitudinal strength, and results in lower open-water navigation resistance compared to the stern resistance of conventional icebreakers.

[0110] 2) The rudder 200 and propeller 300 are far enough from the stern end of the designed waterline to ensure that the rudder 200 and propeller 300 are far enough away from the ice layer, which fundamentally reduces the probability of ice colliding with the rudder 200 and propeller 300.

[0111] 3) The asymmetrical design of the first outer contour surface 212 and the second outer contour surface 213 of the icebreaking structure 21 fully considers the different motion characteristics of ice fragments at the stern 1 in the flow field. That is, the inner side near the center of the ship is kept as vertical as possible to allow the ice fragments to slide out quickly; while the outer side near the hull side adopts a side with a certain slope so that the ice fragments can slide out along the outer side of the hull. In addition, the shape design of the icebreaking structure 21 provides sufficient space for internal structural reinforcement, making it possible to perform ramming icebreaking.

[0112] 4) The smooth transition between the surfaces of the rudder 200 and the support structure 22 can reduce the generation of local vortices and prevent ice from getting stuck.

[0113] Obviously, the above embodiments of this application are merely examples for clear illustration and are not intended to limit the implementation of this application. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A shaft-propeller-driven polar vessel with stern-mounted ramming icebreaking function, characterized in that, Includes a hull (100) and a rudder (200), said hull (100) comprising: Stern (1); Icebreaker (2) includes icebreaking structure (21) and support structure (22). The upper end of icebreaking structure (21) is fixed to the bottom of stern (1), and the lower end of icebreaking structure (21) is connected to support structure (22). The end of icebreaking structure (21) near stern has a straight icebreaking ridge (211). The angle γ between icebreaking ridge (211) and horizontal direction is in the range of 25° to 35°. Each of the support structures (22) is rotatably connected to the rudder (200), and the distance L1 between the rotation axis of each rudder (200) and the stern end of the design waterline is in the range of 0.3B to 0.4B, and the design waterline intersects with the icebreaker (211), where B is the width dimension of the hull (100). The icebreaking structure (21) includes a first outer contour surface (212) and a second outer contour surface (213), the stern end of the first outer contour surface (212) and the stern end of the second outer contour surface (213) intersect at the icebreaking rib (211). The angle between the tangent of the first outer contour surface (212) at the farthest vertical position from the rotation axis of the rudder (200) and the rotation axis is α, and the angle between the tangent of the second outer contour surface (213) at the farthest vertical position from the rotation axis of the rudder (200) and the rotation axis is β, wherein α is less than β; The angle α between the tangent of the first outer contour surface (212) at the farthest vertical position from the rotation axis of the rudder (200) and the rotation axis ranges from 20° to 30°; and / or, the angle β between the tangent of the second outer contour surface (213) at the farthest vertical position from the rotation axis of the rudder (200) and the rotation axis ranges from 35° to 45°.

2. The shaft-propeller-driven polar vessel with stern-ramming icebreaking function according to claim 1, characterized in that, The bow end of the first outer contour surface (212) is smoothly connected to the bow end of the second outer contour surface (213).

3. The shaft-propeller-driven polar vessel with stern-ramming icebreaking function according to claim 2, characterized in that, The first outer contour surfaces (212) of the two icebreakers (2) are arranged opposite to each other.

4. The shaft-propeller-driven polar vessel with stern-ramming icebreaking function according to claim 1, characterized in that, The sum of α and β ranges from 55° to 65°.

5. The shaft-propeller-driven polar vessel with stern-ramming icebreaking function according to claim 2, characterized in that, The distance between the first outer contour surface (212) and the second outer contour surface (213) gradually increases from the bow to the stern and then decreases.

6. The shaft-propeller-driven polar vessel with stern-ramming icebreaking function according to claim 5, characterized in that, The cross-sectional shape of the ice-breaking structure (21) is teardrop-shaped, and the tip of the teardrop shape is located at the ice-breaking ridge (211).

7. The shaft-propeller-driven polar vessel with stern-ramming icebreaking function according to claim 1, characterized in that, The two icebreakers (2) are fixed symmetrically to the bottom of the stern (1) with the center line in the width direction as the axis. The support structure (22) of each icebreaker (2) is rotatably connected to the rudder (200). The distance L2 between the rotation axes of the two rudders (200) is in the range of 0.5B to 0.7B.

8. The shaft-propeller-driven polar vessel with stern-ramming icebreaking function according to any one of claims 1-7, characterized in that, The lower end face of the ice-breaking structure (21) is a plane, the upper end face of the rudder (200) is a plane, and the upper end face of the rudder (200) is in clearance fit with the lower end face of the ice-breaking structure (21).

9. The shaft-propeller-driven polar vessel with stern-ramming icebreaking function according to claim 8, characterized in that, The support structure (22) includes a connecting part (221) and a support part (222). The connecting part (221) is fixedly connected to the lower end face of the icebreaking structure (21). At least two support parts (222) are connected to the connecting part (221) in parallel and spaced along the ship height direction. Each support part (222) is provided with a first shaft hole (2220). The rudder (200) is provided with a second shaft hole (2020) that communicates with the first shaft hole (2220). The rudder (200) is rotatably mounted on the support structure (22) by passing a rotating shaft through the second shaft hole (2020) and the first shaft hole (2220).

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