Method for determining the welding amount of a semi-ship floating drop pier ship body

Abstract

The application discloses a method for determining the welding quantity of a semi-ship floating falling pier ship body, comprising the following steps: (1) determining the semi-ship welding operation area in the dock according to the semi-ship structure and the segmentation division form, including the plate closing seam area, the bone material welding area and the mutation position of the cabin tail section which cannot be closed completely; (2) evaluating the total longitudinal strength of the semi-ship body according to the plate closing seam area determined in step (1); (3) evaluating the local strength of the semi-ship body according to the mutation position of the cabin tail section which cannot be closed completely determined in step (1); (4) when the total longitudinal strength and the local strength in steps (2) and (3) meet the design requirements, determining the longitudinal bone material welding quantity through step (5); (5) calculating the required plate thickness of the ship plane bulkhead plate, comparing the actual plate thickness of the ship plane bulkhead plate with the required plate thickness, and determining the longitudinal bone material welding quantity of the bone material welding area. The application can determine the minimum welding operation quantity of the semi-ship before launching in the dock, and improve the efficiency of the semi-dock loading construction.

Description

TECHNICAL FIELD

[0001] The present application relates to the shipbuilding technical field, and in particular to a method for determining the welding amount of a semi-ship floating landing block ship body. BACKGROUND

[0002] In order to reasonably utilize a ship dock and improve construction efficiency, a whole ship and a semi-ship are generally used for serial construction in the same ship dock, so that when the whole ship is docked, the semi-ship is floated and moved to the position of the whole ship to land a block, and then the closing of the bow semi-ship is started, and the construction of the semi-ship behind the ship dock is continued, and so on. However, when the whole ship and the semi-ship are constructed in parallel, the whole ship and the semi-ship are required to be docked after the welding is completed, which brings great difficulties to the allocation of manpower and material resources, plan management, and the like, and the docking of the whole ship is often subject to the semi-ship in the ship dock. In the traditional construction method, the semi-ship can be docked only after the semi-ship is completely assembled and welded, which causes the problems of prolonging the dock period and increasing the shipbuilding cost, and it cannot be determined whether the welding quality of the semi-ship meets the docking condition. SUMMARY

[0003] To solve the above technical problems, the present application provides a method for determining the welding amount of a semi-ship floating landing block ship body, which evaluates the total longitudinal strength and local strength of the semi-ship, reduces the welding operation amount of the semi-ship in the ship dock before docking under the premise that the strength of the semi-ship meets the safety requirement of the semi-ship floating landing block operation, and creates conditions for the timely delivery of the ship.

[0004] The present application specifically adopts the following technical solutions:

[0005] A method for determining the welding amount of a semi-ship floating landing block ship body, comprising the steps of:

[0006] (1) determining the semi-ship welding operation area in the ship dock according to the semi-ship structure and the section division form, and determining the semi-ship floating draft height requirement and the cabin loading condition; the semi-ship welding operation area in the ship dock includes a plate closing seam area, a bone material welding area, and a mutation position of a tail section of a machinery cabin that cannot be completely closed;

[0007] (2) evaluating the total longitudinal strength of the semi-ship body on the basis of the complete welding of the plate closing seam area determined in step (1);

[0008] (3) evaluating the local strength of the semi-ship body according to the mutation position of the tail section of the machinery cabin that cannot be completely closed determined in step (1);

[0009] (4) When the total longitudinal strength of the half-ship hull and the local strength of the half-ship hull in steps (2), (3) both meet the design requirements, the longitudinal bone welding amount of the bone welding area is determined through step (5), and if steps (2), (3) cannot meet the design requirements, it is considered that the current construction state is not suitable for the half-ship floating operation, and the design scheme of the load distribution cabin or the half-ship closing state needs to be adjusted until steps (2), (3) both meet the design requirements, and then step (5) is executed;

[0010] (5) The required plate thickness of the ship plane bulkhead plate is calculated, and the actual plate thickness of the ship plane bulkhead plate is compared with the required plate thickness to determine the longitudinal bone welding amount of the bone welding area.

[0011] In the above technical solution, adjusting the half-ship closing state means increasing the cargo cabin half-ship ring segment or removing part of the ring segment at the tail of the engine cabin.

[0012] Further, the plate closing seam area in step (1) includes the closing weld seams between the platforms of the engine cabin total segment, the closing ring seams between the engine cabin and the cargo cabin ring segment, the closing ring seams between the cargo cabin ring segments, the closing weld seams between the side section and the intermediate deck section, the transverse bulkhead section and the double-bottom section, and the closing weld seams between the side deck and the side bilge section.

[0013] Further, step (2) is specifically:

[0014] (21) Determine the total longitudinal strength evaluation cross section of different regions of the half-ship;

[0015] (22) Calculate the actual maximum total longitudinal bending moment that can be borne by the different regions of the half-ship cross section, i.e. the actual total longitudinal bending moment of the half-ship, and calculate the theoretical total longitudinal bending moment that can be borne by the different regions of the half-ship cross section under the floating landing pad working condition, i.e. the design total longitudinal bending moment of the half-ship;

[0016] (23) Calculate the actual maximum shear force that can be borne by the different regions of the half-ship cross section, i.e. the actual shear force of the half-ship, and calculate the theoretical shear force that can be borne by the different regions of the half-ship cross section under the floating landing pad working condition, i.e. the design shear force of the half-ship;

[0017] (24) Compare the actual maximum total longitudinal bending moment and shear force that can be borne by the different regions of the half-ship cross section calculated with the theoretical total longitudinal bending moment and shear force that can be borne by the different regions of the half-ship cross section under the floating landing pad working condition, to determine whether the actual total longitudinal strength of the half-ship meets the requirements.

[0018] Further, the calculation formula of the actual maximum total longitudinal bending moment of the different regions of the half-ship cross section in step (22) is:

[0019] M = σ × Z X

[0020] Wherein, σ is the minimum allowable stress of the hull beam; Z X is the smaller of the section modulus at the bottom and the section modulus at the deck.

[0021] Further, the step (22) includes adding the half-ship static water bending moment and the half-ship wave bending moment of different cross sections to obtain the theoretical total longitudinal bending moment of the half-ship in the floating and landing condition.

[0022] The half-ship static water bending moment should be calculated according to the bending theory of a straight beam.

[0023] The formula for calculating the wave bending moment of the half-ship at any longitudinal position is:

[0024] The hogging state:

[0025] M ωv-h = 0.19f nl-vh f m f p C W L 2 BC B

[0026] The sagging state:

[0027] M ωυ-s = -0.19f nl-vs f m f p C W L 2 BC B

[0028] Wherein, M ωυ-h is the wave bending moment in the hogging state, M ων-s is the wave bending moment in the sagging state; f nl-vh is a coefficient for considering the nonlinear effect in the hogging state; f nl-vs is a coefficient for considering the nonlinear effect in the sagging state; f m is a distribution coefficient of the vertical wave bending moment along the ship length; f p = f ps , f ps is a strength evaluation coefficient corresponding to the design load setting; C W is a wave coefficient; L is the ship length; B is the ship width; C B is a square coefficient.

[0029] Further, the step (23) includes calculating the theoretical shear force of the different cross sections of the half ship in the floating and landing condition, which includes the static water shear force and the vertical wave shear force.

[0030] The static water shear force of the half ship should be calculated according to the bending theory of straight beams.

[0031] The calculation formula of the vertical wave shear force of the half ship at any longitudinal position is as follows:

[0032] Positive wave shear force:

[0033] Q ωυ-pos = 0.52f q-pos f p C W LBC B

[0034] Negative wave shear force:

[0035] Q ωυ-neg = -0.52f q-neg f p C W LBC B

[0036] Wherein, f q-pos is the distribution coefficient of the positive wave shear force along the ship length; f q-neg is the distribution coefficient of the negative wave shear force along the ship length; f p = f os , f ps is the strength evaluation coefficient corresponding to the design load setting; C W is the wave coefficient; L is the ship length; B is the ship width; C B is the square coefficient.

[0037] Further, the step (3) is specifically to evaluate the local strength of the sudden change position of the engine room tail section segment that cannot be completely closed, including the steps of:

[0038] (31) According to the half ship structure, a half ship floating finite element model is established, the hull shell, cabin boundary, platform, longitudinal girder, main support member, hatch coaming plate and hatch coaming panel are simulated by plate elements, other bones are simulated by beam elements, and the grid is set;

[0039] (32) Set the half ship local strength checking load, including applying the half ship gravity load, applying seawater pressure in the outer plate area, and applying ballast water gravity load on the cabin bottom plate in the ballast cabin;

[0040] (33) Set the boundary condition of the half-ship local strength checking, that is, adopt the inertia release method, and take the center of the outer bottom half-ship close to the ship center as the constraint point;

[0041] (34) Analyze the stress calculation results of the plate unit and the beam unit through the finite element simulation, and compare them with the allowable stress of the half-ship structure to determine whether the mutation position of the cabin tail section that cannot be completely closed meets the requirements.

[0042] Further, the step (5) is specifically:

[0043] (51) Calculate the required plate thickness t of the ship plane bulkhead plate, and ensure that the actual plate thickness T of the ship plane bulkhead plate meets T≥[t, 5.5] min, and the calculation formula of the required plate thickness t of the ship plane bulkhead plate is:

[0044]

[0045] Wherein, s is the reinforcement spacing; h is the half-ship draft height or the ballast tank head height, and a safety margin of 1 meter water head is added to the design value; when the calculation target is the plate in contact with seawater, the value of h is selected as the draft height; when the calculation target is the plate in contact with the ballast water, the value of h is selected as the ballast tank head height, ρ is the liquid density, t / m3, and the value should not be less than 1.025 during calculation; k is the material coefficient;

[0046] (52) According to the relationship between the required plate thickness of the ship plane bulkhead plate and the longitudinal bone material welding amount requirement, the longitudinal bone material welding amount requirement corresponding to the required plate thickness of the ship plane bulkhead plate closest to the actual plate thickness of the ship plane bulkhead plate is selected as the longitudinal bone material welding amount of the half-ship bone material welding area

[0047] The present application has the following beneficial effects:

[0048] The present application provides a method for determining the half-ship floating landing pier ship body welding amount, which evaluates the half-ship overall longitudinal strength and local strength, reduces the welding operation amount before the half-ship is launched in the dock under the premise that the half-ship strength fully meets the safety requirements of the half-ship floating landing pier operation, improves the half-ship dock loading construction efficiency, provides a theoretical basis for reasonable allocation of shipbuilding construction personnel, and creates conditions for the timely delivery of ships; and when evaluating the half-ship overall longitudinal strength, the present application adopts a transverse section simplification method, which not only accurately calculates the strength, but also improves the calculation efficiency, and in addition, the present application combines the finite element method to analyze and judge the local strength of the half-ship when evaluating the strength, so as to ensure that the ship body will not deform during the half-ship floating landing pier process. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 The flowchart of the present application;

[0050] Figure 2 A schematic diagram of the half-ship structure of the present application;

[0051] Figure 3 A calculation model of the FR51 section;

[0052] Figure 4 A simulation cloud chart for checking the local strength of the half-ship. DETAILED DESCRIPTION

[0053] The specific embodiments of the present application will be further described below in conjunction with the drawings and specific embodiments.

[0054] Referring to Figure 1 and Figure 2 , this embodiment takes a 210,000-ton bulk carrier as an example, the half-ship structure of which is the ring section from the partial engine room area to the cargo hold area, the average draft of the half-ship when floating is about 3.24 meters, and the water level in the cargo hold is about 2.80 meters from the cargo hold bottom plate. The welding amount of the half-ship floating on the pier is evaluated and determined, including the following steps:

[0055] (1) Determine the half-ship welding operation area in the dock according to the half-ship structure and the section division form, and determine the half-ship floating draft height requirement and the cabin loading condition; the half-ship welding operation area in the dock includes the plate closing seam area, the frame welding area, and the mutation position of the engine room tail section that cannot be completely closed.

[0056] In this step, the half-ship structure includes the engine room area, the cargo hold area, and the tail area, the plate closing seam area includes the closing weld seams between the platforms of the engine room section, the closing ring seams between the engine room and the cargo hold ring section, the closing ring seams between the cargo hold ring sections, the closing weld seams between the side sections and the intermediate deck section, the transverse bulkhead section, and the double-bottom section, and the closing weld seams between the side deck and the side bilge section.

[0057] (2) Based on the plate closing seam area determined in step (1), evaluate the overall longitudinal strength of the half-ship hull after all the plate closing seam areas are completely welded. Specifically:

[0058] (21) Determine the overall longitudinal strength evaluation cross section of different areas of the half-ship;

[0059] (22) Calculate the actual maximum overall longitudinal bending moment that can be borne by the cross section of different areas of the half-ship, i.e. the actual overall longitudinal bending moment of the half-ship; and calculate the theoretical overall longitudinal bending moment that can be borne by the cross section of different areas of the half-ship under the floating on the pier working condition, i.e. the design overall longitudinal bending moment of the half-ship;

[0060] (23) Calculate the actual maximum shear force that can be borne by the cross section of different areas of the half-ship, i.e. the actual shear force of the half-ship; and calculate the theoretical shear force that can be borne by the cross section of different areas of the half-ship under the floating on the pier working condition, i.e. the design shear force of the half-ship;

[0061] (24) The actual maximum total longitudinal bending moment and shear force that can be borne by the different regions of the calculated half-ship are compared with the theoretical total longitudinal bending moment and shear force borne by the different regions of the half-ship in the floating landing condition, to determine whether the actual total longitudinal strength of the half-ship meets the requirements.

[0062] In this step, in the specific calculation process, because the number of closure joints is large, a typical cross section can be selected according to the characteristics of the half-ship for evaluation. Specifically, in the engine room area, when the half-ship engine room area is complete, the middle cross section can be selected for calculation and evaluation; if the engine room area is partially involved in the half-ship construction, the cross section near the cargo hold area should be added to the above cross section for calculation and evaluation; in the cargo hold area, the cross section at the position of the maximum hydrostatic bending moment within the half-ship construction range is selected for calculation and evaluation; in the tail area, because the ship structure in the tail area is mostly located above the half-ship floating waterline, the cross section near the engine room area (such as the engine room rear wall area) can be selected for calculation and evaluation. In this embodiment, the FR51, FR45, FR30 and FR14 cross sections are selected for calculation.

[0063] The actual maximum total longitudinal bending moment of the different regions of the half-ship is calculated as follows:

[0064] According to the cross section structure of different regions of the ship, a calculation model of different cross sections is established by using the calculation software of the ship classification society, the cross section modulus of each cross section is calculated through the established calculation model, and the smaller value of the cross section modulus at the ship bottom and the cross section modulus at the deck is selected to calculate the maximum total longitudinal bending moment that can be borne by the different regions of the half-ship in the calculation process. According to the formula M = σ × Z X , the actual maximum total longitudinal bending moment of the cross section of the cargo hold area is calculated. Taking the FR51 cross section as an example, as shown in Figure 3 , the cross section calculation model of FR51 is shown, through calculation, the cross section modulus at the deck at the position of FR51 is 3.662m 3 , the cross section modulus at the bottom of the ship is 5.315m 3 , and the minimum allowable bending stress of the hull beam in the CCS Ship Classification Society “Steel Sea-going Ship Classification Rules” is 105 / KN / mm 2 , the minimum allowable bending stress at this cross section is 105 / k = 105 / 0.72 = 145.8N / mm 2 , so the maximum total longitudinal bending moment that can be borne by the FR51 cross section is Mtotal51 = 3.662x145.8x1000 = 533919.6KN·m. The actual maximum total longitudinal bending moment of the FR51, FR45, FR30 and FR14 cross sections obtained by this calculation method is shown in the following Table 1.

[0065] Table 1

[0066]

[0067]

[0068] Theoretical total longitudinal bending moment of the different area cross section of the half ship under the floating and landing condition, that is, the design total longitudinal bending moment, includes the half ship hydrostatic bending moment and the half ship wave bending moment. The half ship hydrostatic bending moment and the half ship wave bending moment of different cross sections are added respectively to obtain the theoretical total longitudinal bending moment of the different area cross section of the half ship under the floating and landing condition, which is calculated as follows:

[0069] The half ship hydrostatic bending moment is simulated and calculated by using the napa software according to the bending theory of straight beam. The calculation results of the cross sections of FR51, FR45, FR30 and FR14 are shown in Table 2.

[0070] Table 2

[0071]

[0072] The calculation formula of the wave bending moment of any longitudinal position of the half ship is as follows:

[0073] Sagging state:

[0074] M ωυ-h = 0.19f nl-vh f m f p C W L 2 BC B

[0075] Sagging state:

[0076] M ωυ-s = -0.19f nl-vs f m f p C W L 2 BC B

[0077] The wave bending moment of the longitudinal position of the cross sections of the half ship FR51, FR45, FR30 and FR14 is calculated according to the above formula and shown in Table 3.

[0078] Table 3

[0079]

[0080] The theoretical total longitudinal bending moment of the cross sections of the half ship FR51, FR45, FR30 and FR14 under the floating and landing condition, that is, the design bending moment, is obtained and shown in Table 4.

[0081] Table 4

[0082]

[0083] The calculation process of the actual maximum shear force that can be borne by the different areas of the half-ship cross section is as follows:

[0084] For the rib position with a complete ring segment, the longitudinal arrangement component should ensure the structural continuity, that is, the shear force continuity in the transverse cross section, the shear-resistant components in the ring segment (the inner longitudinal wall plate, the longitudinal plate, and the outer plate) are welded completely, it is determined that the shear resistance of the half-ship in the floating state in the complete ring segment is basically the same as the shear resistance of the whole ship, and the shear strength in the complete ring segment area meets the requirements; for the rib position with an incomplete ring segment, the shear resistance of the corresponding cross section is obtained through the simulation calculation of the calculation software of the ship classification society. The calculation model of the shear resistance is the same as that of the FR51 cross section shown in FIG. 1, and the cross section modulus and the shear resistance can be calculated. The shear resistance of the FR51 is 75189 KN. The actual maximum shear force that can be borne by the FR51, FR45, FR30, and FR14 cross sections is shown in Table 5. Figure 3

[0085] Table 5

[0086]

[0087] The theoretical shear force borne by the half-ship cross section in the floating and landing condition, that is, the design shear force, the theoretical shear force borne includes the half-ship static water shear force and the vertical wave shear force. The half-ship static water shear force and the vertical wave shear force of different cross sections are added respectively to obtain the theoretical shear force borne by the half-ship cross section in the floating and landing condition. The calculation process is as follows:

[0088] The half-ship static water shear force is simulated and calculated by using the napa software according to the bending theory of the straight beam. The calculation results of the static water shear force of the FR51, FR45, FR30, and FR14 cross sections are shown in Table 6.

[0089] Table 6

[0090]

[0091]

[0092] The calculation formula of the vertical wave shear force of the half-ship at any longitudinal position is as follows:

[0093] Q ωv-pos =0.52f q-pos f p C W LBC B

[0094] Q ωυ-neg =-0.52f q-neg f p C w LBC​B

[0095] The vertical wave shear force of the half-ship FR51, FR45, FR30, and FR14 sections calculated according to the above formula is shown in Table 7.

[0096] Table 7

[0097]

[0098] Thus, the theoretical shear force borne by the different area cross sections of the half-ship in the floating landing condition, i.e., the design shear force, is obtained, as shown in Table 8. It should be noted that the maximum value of the absolute value of Q ω v-pos , Q ω v-neg is selected in the calculation process and is superimposed with the static water shear force for calculation.

[0099] Table 8

[0100]

[0101] The actual maximum total longitudinal bending moment and shear force borne by the different area cross sections of the half-ship obtained by the above calculation are compared with the theoretical total longitudinal bending moment and shear force borne by the different area cross sections of the half-ship in the floating landing condition, to determine whether the actual total longitudinal strength of the half-ship meets the requirements, and the checking results are shown in Tables 9 and 10, respectively, and the total longitudinal strength meets the requirements.

[0102] Table 9 Summary of total longitudinal bending moment calculation results

[0103]

[0104]

[0105] Table 10 Summary of shear force calculation results

[0106]

[0107] (3) The local strength of the half-ship hull is evaluated according to the abrupt change position at which the aft section of the engine room cannot be completely closed determined in step (1).

[0108] This step specifically includes the following steps of evaluating the local strength of the abrupt change position at which the aft section of the engine room cannot be completely closed using the finite element method:

[0109] (31) According to the half-ship structure, a floating finite element model of the half-ship is established, the hull shell, cabin boundary, platform, longitudinal girder, main support member, hatch coaming plate, and hatch coaming panel are simulated by plate elements, and other bones are simulated by beam elements, and a grid is set;

[0110] (32) Set up the loading load for the local strength check of the half ship, including applying the gravity load of the half ship, applying the sea water pressure in the outer plate area, and applying the gravity load of the ballast water in the ballast cabin;

[0111] (33) Set up the boundary condition for the local strength check of the half ship, i.e. using the inertia release method, and taking the center of the outer bottom half ship close to the center of the ship as the constraint point;

[0112] (34) Analyze the stress calculation results of the plate unit and the beam unit through the finite element simulation, compare them with the allowable stress of the half ship structure, and judge whether the mutation position where the engine room tail section cannot be completely closed meets the requirements.

[0113] In this embodiment, the local strength of the non-integrated area of the half ship ring section is checked. The local strength check result is judged by comparing the stress calculation results of the plate unit and the beam unit with the allowable stress of the ship structure. The local strength check result of the 210,000-ton bulk carrier half ship is shown in FIG. 21, wherein (a) and (b) are the stress calculation results of the plate unit and the beam unit, respectively. Figure 4

[0114] The stress calculation results of the plate unit and the beam unit are compared with the allowable stress of the ship structure, as shown in Table 11 below, which meets the requirements.

[0115] Table 11

[0116]

[0117] (4) The longitudinal strength of the half ship body and the local strength of the half ship body in the above steps (2) and (3) meet the design requirements, and the longitudinal bone welding amount of the bone welding area is determined through step (5).

[0118] (5) The required plate thickness of the ship plane bulkhead plate is calculated, and the actual plate thickness of the ship plane bulkhead plate is compared with the required plate thickness to determine the longitudinal bone welding amount of the bone welding area. This step is specifically as follows:

[0119] (51) The required plate thickness t of the ship plane bulkhead plate is calculated to ensure that the actual plate thickness T of the ship plane bulkhead plate meets T≥[t, 5.5] min. The calculation formula of the required plate thickness t of the ship plane bulkhead plate is:

[0120]

[0121] ​Wherein, s is the spacing of the stiffening material; h is the half-ship water height or the height of the ballast chamber pressure head, and a 1-meter water pressure head is added as a safety margin on the basis of the design value, and when the calculation target is a plate in contact with seawater, the value of h is selected as the water height; when the calculation target is a plate in contact with ballast water, the value of h is selected as the height of the ballast chamber pressure head, and p is the density of the liquid, t / m3, and the value should not be less than 1.025 in calculation; k is the material coefficient;

[0122] (52) According to the relationship between the required plate thickness of the ship plane bulkhead plate in different regions and the longitudinal bone material welding requirement, the longitudinal bone material welding requirement corresponding to the required plate thickness of the ship plane bulkhead plate closest to the actual plate thickness of the ship plane bulkhead plate is selected as the longitudinal bone material welding amount of the half-ship bone material welding region. The relationship between the required plate thickness of the outer bottom plate and the longitudinal bone material welding requirement is shown in Table 12, and then the outer bottom plate region bone material spacing 1 root is welded 1 root under the condition that the half-ship floating design water height is 1 m below in the 210,000-ton bulk carrier of the embodiment.

[0123] Table 12

[0124]

[0125] It should be noted that Table 12 is a conclusion obtained by statistical comparison, and is designed and verified by referring to the requirements of the ship classification society for the watertight bulkhead. The bone material that has not been welded is regarded as invalid. By comparing the thickness required by the outer plate with the actual thickness of the ship outer plate under the condition of seawater pressure load in the floating state and different bone material failure quantities, the bone material failure quantity that can meet the local strength requirement is determined, and the minimum bone material welding quantity requirement is obtained.

[0126] On the basis of the above bone material welding, the bone material strength of the outer bottom plate region is verified as shown in Table 13.

[0127] Table 13

[0128]

[0129] It is determined from the calculation results of Table 13 that the local strength of the bone material meets the requirements under the above minimum bone material welding quantity.

[0130] Similarly, for other regions, the bone material welding amount of other regions is determined according to the relationship between the required plate thickness of the region and the longitudinal bone material welding requirement, so as to obtain the minimum bone material welding amount of all half-ship bone material welding regions. The bone material welding amount determined in the embodiment is as follows:

[0131] (1) The main plate at the ring joint position is welded completely (including the double-bottom longitudinal girder);

[0132] (2) The bone material spacing 1 root is welded 1 root in the outer bottom plate region below the half-ship floating design water height 1 m;

[0133] (3) The inner bottom plate area of the ballast hold is welded with one longitudinal between two longitudinal materials;

[0134] (4) The bottom edge of the hold is welded with one longitudinal between two longitudinal materials in the area of the hold slope plate;

[0135] (5) The side plate is welded with one longitudinal between two longitudinal materials in the area of the half-ship floating design below 1m water level;

[0136] (6) Considering that the deck end is far away from the neutral axis of the transverse section, the section modulus of the section is greatly contributed, and it is suggested that one longitudinal is welded between the deck longitudinal, the side plate longitudinal and the top edge of the hold slope plate within 3m of the deck.

[0137] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or replacements made by the skilled in the art within the essential scope of the present application shall also belong to the protection scope of the present application.

Claims

1. A method for determining the amount of welding of a semi-planing floating landing block ship body, characterized in that, The method comprises the steps of: (1) determining a half-ship welding operation area in a dock according to a half-ship structure and a segmentation division form, and determining a half-ship floating draft height requirement and a cabin allocation condition; the half-ship welding operation area in the dock comprises a plate closing seam area, a skeleton welding area, and a mutation position of a machine cabin tail section segment that cannot be closed completely; (2) according to the plate closing seam area determined in step (1), evaluating the total longitudinal strength of the half-ship hull after the plate closing seam area is completely welded; (3) according to the mutation position of the machine cabin tail section segment that cannot be closed completely determined in step (1), evaluating the local strength of the half-ship hull; (4) when the total longitudinal strength of the half-ship hull and the local strength of the half-ship hull in steps (2) and (3) both meet the design requirements, determining the longitudinal skeleton welding amount of the skeleton welding area through step (5); if the total longitudinal strength of the half-ship hull and the local strength of the half-ship hull in steps (2) and (3) cannot meet the design requirements, it is considered that the current construction state is not suitable for half-ship floating operation, and the allocation cabin design scheme or the half-ship closing state needs to be adjusted until the total longitudinal strength of the half-ship hull and the local strength of the half-ship hull in steps (2) and (3) both meet the design requirements, and then step (5) is performed; (5) calculating a required plate thickness of a ship plane bulkhead plate, comparing an actual plate thickness of the ship plane bulkhead plate with the required plate thickness, and determining the longitudinal skeleton welding amount of the skeleton welding area.

2. The method of determining the welding amount of a semi-ship floating landing pad ship body according to claim 1, characterized in that, The plate closing seam area in step (1) comprises closing weld seams between platforms of a machine cabin section, closing ring seams between a machine cabin and a cargo cabin ring section, closing ring seams between cargo cabin ring sections, closing weld seams between a side section and a middle deck section, a transverse bulkhead section and a double-bottom section, and closing weld seams between a side deck and a side bilge section.

3. The method of determining the amount of welding for a semi-planing floating landing pad boat hull of claim 1, wherein, Step (2) specifically comprises: (21) determining total longitudinal strength evaluation cross sections of different regions of the half-ship; (22) calculating actual maximum bearable total longitudinal bending moments of the cross sections of the different regions of the half-ship, i.e., actual total longitudinal bending moments of the half-ship; and calculating theoretical bearable total longitudinal bending moments of the cross sections of the different regions of the half-ship under a floating landing condition, i.e., design total longitudinal bending moments of the half-ship; (23) calculating actual maximum bearable shears of the cross sections of the different regions of the half-ship, i.e., actual shears of the half-ship; and calculating theoretical bearable shears of the cross sections of the different regions of the half-ship under the floating landing condition, i.e., design shears of the half-ship; (24) comparing the actual maximum bearable total longitudinal bending moments and shears of the cross sections of the different regions of the half-ship with the theoretical bearable total longitudinal bending moments and shears of the cross sections of the different regions of the half-ship under the floating landing condition, to determine whether the actual total longitudinal strength of the half-ship meets the requirements.

4. The method of determining the amount of welding of a semi-planing floating landing pad boat body of claim 3, wherein, The calculation formula of the actual maximum bearable total longitudinal bending moment of the cross section of the different regions of the half-ship in step (22) is: wherein, is the minimum value of the allowable stress for the hull girder; is the lesser of the section modulus at the bottom of the ship and the section modulus at the deck.

5. The method of determining the amount of welding for a semi-planing floating landing pad boat hull of claim 3, wherein, The theoretical bearable total longitudinal bending moment of the cross section of the different regions of the half-ship under the floating landing condition in step (22) comprises a half-ship static water force bending moment and a half-ship wave bending moment, and the half-ship static water force bending moment and the half-ship wave bending moment of different cross sections are added respectively to obtain the theoretical bearable total longitudinal bending moment of the cross section of the different regions of the half-ship under the floating landing condition; The half-ship static water bending moment should be calculated according to the bending theory of a straight beam; The calculation formula of the wave bending moment of any longitudinal position of the half-ship is: cambered state: Sag state: wherein, is the wave bending moment for hogging condition, is the wave bending moment for sagging condition; is the coefficient for considering the nonlinear effect for hogging; is the coefficient for considering the nonlinear effect for sagging; is the distribution coefficient of the vertical wave bending moment along the ship length; = 1.0 , is the strength assessment coefficient corresponding to the applicable design load setting; is the wave coefficient; is the ship length; is the ship breadth; is the square coefficient.

6. The method of determining the amount of welding for a semi-planing floating landing pad boat hull of claim 3, wherein, The step (23) includes the step of adding the half-ship static water shear force and the vertical wave shear force of different cross sections of the half-ship to obtain the theoretical shear force of the cross section of the half-ship in the floating and landing condition; The half-ship static water shear force should be calculated according to the bending theory of a straight beam; The formula for calculating the vertical wave shear force of the half-ship at any longitudinal position is: Positive wave shear force: Negative wave shear force: wherein, is the distribution coefficient of positive wave shear force along the length of the ship; is the distribution coefficient of negative wave shear force along the length of the ship; , is the strength assessment coefficient corresponding to the applicable design load setting; is the wave coefficient; is the length of the ship; is the width of the ship; is the square coefficient.​ 7. The method of determining the amount of welding for a semi-planing floating landing pad boat hull of claim 1, wherein, The step (3) is specifically to evaluate the local strength of the abrupt position of the cabin tail section that cannot be completely closed by using the finite element method, including the steps of: (31) According to the half-ship structure, a half-ship floating finite element model is established, the hull shell, cabin boundary, platform, longitudinal girder, main support member, hatch coaming plate and hatch coaming panel are simulated by plate elements, other bones are simulated by beam elements, and the grid is set; (32) Set the half-ship local strength checking load, including applying the half-ship gravity load, applying the seawater pressure in the outer plate area, and applying the ballast water gravity load on the cabin bottom plate in the ballast cabin; (33) Set the half-ship local strength checking boundary condition, that is, use the inertia release method to take the center of the outer bottom half-ship close to the center of the ship as the constraint point; (34) Analyze the stress calculation results of the plate elements and beam elements by finite element simulation, and compare them with the allowable stress of the half-ship structure to determine whether the abrupt position of the cabin tail section that cannot be completely closed meets the requirements.

8. The method of determining the amount of welding for a semi-planing floating landing pad boat hull of claim 1, wherein, The step (5) is specifically: (51) Calculate the required plate thickness t of the ship plane bulkhead plate to ensure that the actual plate thickness T of the ship plane bulkhead plate meets T≥[t, 5.5]min, and the calculation formula of the required plate thickness t of the ship plane bulkhead plate is: wherein, is the distance between the stiffeners; is the half-ship water depth or the height of the ballast chamber head, and is increased by 1 meter of water head as a safety margin based on the design value, and when the calculation target is a plate in contact with seawater, is the water depth, and when the calculation target is a plate in contact with ballast water, is the height of the ballast chamber head, is the liquid density, t / m 3 , and the value taken when calculating should not be less than 1.025; is the material coefficient; (52) According to the relationship between the required plate thickness of the ship plane bulkhead plate and the longitudinal bone welding amount requirement, the longitudinal bone welding amount corresponding to the required plate thickness of the ship plane bulkhead plate closest to the actual plate thickness of the ship plane bulkhead plate is selected as the longitudinal bone welding amount of the half-ship bone welding area.

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