A method for building large sections of a container ship hull

Abstract

The application discloses a container ship large box segment construction method and belongs to the ship construction technical field. The method obtains a three-dimensional design model of a container ship large box, divides the large box into multiple box segments according to the projection of the transverse bulkhead and the container guide rail center line, extracts the guide rail base elevation, the bulkhead perpendicularity tolerance and the strong crossbeam position of each box segment to generate a segment construction control parameter set, divides the plate column according to the segment construction control parameter set, determines the bevel direction according to the rolling direction, generates a plate column assembly sequence, assembles each plate column into a box with an open port, installs a support frame on the open port, adjusts the support point height of the support frame by using the segment construction control parameter set, obtains a limited box, symmetrically welds the limited box with the longitudinal middle section as the symmetric plane, measures the transverse shrinkage after completing each welding pass, converts the transverse shrinkage into the transverse offset of the arc starting point of the next welding pass and continues to weld, and forms the large box segment.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, specifically to a method for constructing large container ship hull sections. Background Technology

[0002] Large container ship hull sections consist of components such as bottom plates, side plates, top plates, transverse bulkheads, strong beams, and guide rail bases. During the assembly and welding of these components, high precision is required for the guide rail base elevation, bulkhead verticality, and hull interface dimensions. Current construction methods typically divide the hull into sections using hull ribs or compartments as boundaries, assembling the sections on universal jigs, using fixed supports and temporary stops for positioning, and then determining the welding sequence and shrinkage compensation amount based on experience.

[0003] After large box-type sections form openings in the bow and stern directions, the structural stiffness near the opening ports is low, and the required support height at different locations along the box cross-section varies with the elevation of the guide rail base and the position of the strong crossbeam. Universal jigs and fixed supports cannot be adjusted differently based on the guide rail base elevation, bulkhead verticality tolerance, and strong crossbeam position of each box segment. Before panel assembly and welding, the opening ports are difficult to achieve a constrained state consistent with the design alignment, easily leading to localized collapse and cross-sectional deformation in the port area. Subsequent welding deformation further amplifies this deformation at the guide rail base and bulkhead interface area. Simultaneously, the lateral shrinkage during the welding of thick plates and long welds is unevenly distributed along the weld length. Existing methods generally reserve uniform shrinkage based on empirical values ​​or compensate according to a fixed welding sequence, failing to utilize the measured shrinkage of already welded welds to correct the arc starting position of the next weld. This results in lateral misalignment of subsequent welds relative to previous welds, increasing segmental twisting and residual stress.

[0004] To address the aforementioned issues, it is necessary to eliminate the mismatch between the support height of the opening port and the segment construction control parameters after the large box-type segment division, and to improve the problem of not correcting the lateral offset of the arc starting point of subsequent welds based on the measured lateral shrinkage amount of each pass during the symmetrical welding process. Summary of the Invention

[0005] This invention aims to provide a method for constructing large container ship hull sections, addressing the problems in existing construction methods such as the mismatch between the support height of the opening port and the control parameters for section construction, and the failure to correct the lateral offset of the arc starting point of subsequent welds step by step based on the measured lateral shrinkage.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a method for constructing large container ship hull sections, comprising: Obtain a 3D design model of the large container ship hull, divide the large hull into multiple hull segments according to the projection of the transverse bulkhead and the center line of the container guide rail, and extract the guide rail base elevation, bulkhead verticality tolerance and strong crossbeam position of each hull segment to generate a set of segment construction control parameters; Based on the segment construction control parameter set, each box segment is divided into plate rows, and the bevel direction is determined according to the rolling direction of each plate row to generate the plate row assembly sequence; Assemble each plate column into a box with an open port according to the plate column assembly sequence, install a support frame at the open port, and adjust the support point height of the support frame using the segment construction control parameter set to obtain a limited box; The limiting box is welded symmetrically with the longitudinal mid-section as the symmetrical surface. After each weld pass is completed, the lateral shrinkage is measured and converted into the lateral offset of the arc starting point of the next weld pass. The subsequent weld passes are completed according to the lateral offset of the arc starting point to form a large box segment.

[0007] As a technical solution of this invention, when dividing a large container into multiple segments based on the projection of the transverse bulkhead and the centerline of the container guide rail, the projection line of the centerline of the container guide rail on the plane of the transverse bulkhead is used as the segment division generatrix. A closed segmentation loop is obtained by projecting along the segment division generatrix towards the outer panel of the large container. The three-dimensional design model of the large container is then cut along the closed segmentation loop, and each segment is assigned a segment number according to the cutting sequence, generating a correspondence table between the segment number and the interface coordinates. This solution ensures that the segment division position corresponds to the guide rail and bulkhead structure, which helps improve the accuracy of interface positioning.

[0008] As a technical solution of this invention, when extracting the guide rail base elevation, bulkhead verticality tolerance, and strong beam position of each box segment to generate a segment construction control parameter set, the rib position and deck level of the guide rail base of each box segment are read from the 3D design model. The guide rail base elevations are arranged into a base elevation array according to the rib position. The bulkhead verticality tolerance is read and associated with the corresponding box segment interface. The strong beam position is converted into relative coordinates with the center point of the box segment as the origin. The relative coordinates are merged with the base elevation array and the bulkhead verticality tolerance to form a segment construction control parameter set. The above processing unifies and associates multiple control quantities, providing a consistent control benchmark for subsequent plate assembly and port height adjustment.

[0009] As a technical solution of this invention, each box segment is divided into plate rows according to the segment construction control parameter set, and the bevel direction is determined according to the rolling direction of each plate row. When generating the plate row assembly sequence, the longitudinal stiffener spacing in each box segment is used as the dividing width, and the bottom plate, side plate, and top plate of the box segment are sequentially divided into multiple plate rows. The rolling direction arrow marked on each plate row is read, and the rolling direction arrow is compared with the length direction of the box segment to generate a direction angle mark. Plate rows with the same direction angle mark are grouped into the same assembly batch, and the plate row assembly sequence is generated by arranging them from the center to both sides according to the assembly batch. Unifying the bevel direction and plate row batch according to the rolling direction can reduce assembly internal stress and bevel misalignment.

[0010] As a technical solution of the present invention, when assembling the plate columns into a box with open ports according to the plate column assembly sequence, the first plate column in the assembly sequence is placed on the reference surface of the jig, and temporary positioning blocks are installed at the four corner points of the plate column; subsequent plate columns are then attached one by one along the longitudinal edge of the jig reference surface, and the butt joint between the attached plate column and the already positioned plate column is tack welded; after all plate columns are in place, the edge of the plate column on the stern side of the box segment is cut to form the open port. The temporary positioning blocks and tack welding ensure the stability of the plate column position, and the open port provides working space for subsequent support adjustment and welding stress release.

[0011] As a technical solution of the present invention, when installing the support frame at the opening port, multiple vertical support rods are spaced apart along the circumferential edge of the opening port, and diagonal braces are installed at the corner points of the opening port; the top ends of each vertical support rod are connected sequentially by a transverse connecting rod to form a ring-shaped support frame; an adjustment gap is maintained between the ring-shaped support frame and the edge of the plate array at the opening port, and an adjustment screw is installed on each vertical support rod, so that the height of the top end of the vertical support rod can be changed by adjusting the screw. This structure not only improves the support rigidity, but also allows for fine adjustment of the support point height by adjusting the screw.

[0012] As a technical solution of this invention, when adjusting the support point height of the support frame using a segmental construction control parameter set to obtain the limiting box, the elevation of the guide rail base is read from the segmental construction control parameter set, and the guide rail base elevations are sorted into a height trend sequence according to the width direction of the opening port. The central measurement section of the opening port is selected as the starting section, and each support point on the starting section is adjusted to the relative height corresponding to the height trend sequence. Starting from the starting section, each support point is adjusted section by section along both sides of the opening port so that the support point height of the current section is located on the extension line of the line connecting the support point heights of adjacent adjusted sections. After the support point height adjustment is completed, the limiting box is obtained. Using the guide rail base elevation trend for support point height interpolation adjustment can make the height distribution of the box port consistent with the design alignment, reducing port misalignment during subsequent closure.

[0013] As a technical solution of the present invention, when welding the limiting box body symmetrically with the longitudinal mid-section as the symmetrical plane, corresponding weld mirror points are marked on both sides of the longitudinal mid-section of the limiting box body, dividing each transverse weld into a right half weld and a left half weld located on the left and right sides of the longitudinal mid-section; the starting segment of the right half weld is welded, and the corresponding starting segment of the left half weld is welded; the entire transverse weld is completed in the alternating sequence of the right half weld and the left half weld, and the welding torch axis is aligned with the mirror mark line of the weld segment before the arc is started for each weld segment. This welding method can reduce transverse bending and torsional deformation caused by asymmetrical heat input.

[0014] As a technical solution of the present invention, when measuring the lateral shrinkage of each weld bead, after the weld bead has cooled to a set temperature, multiple shrinkage measurement points are arranged at predetermined intervals along the length of the weld bead. A width measuring caliper is placed across the weld bead at each measurement point to read the distance between the two sides of the weld bead. The distance values ​​of adjacent shrinkage measurement points are then compared to obtain the lateral shrinkage sequence for each measurement interval. Through multi-point measurement and difference processing, the shrinkage distribution along the length of the weld bead can be reflected, providing data for positioning the next weld bead.

[0015] As a technical solution of the present invention, the lateral shrinkage is converted into the lateral offset of the arc starting point of the next weld pass. When completing subsequent weld passes according to the lateral offset of the arc starting point, multiple measurement intervals are selected along the length of the completed weld pass, and the lateral shrinkage corresponding to each measurement interval is recorded. The boundary of the measurement interval with the largest lateral shrinkage is taken as the reference position of the arc starting point. The reference position of the arc starting point is moved by a preset step along the length of the completed weld pass towards the unwelded side, and the moved position is offset towards the adjacent measurement interval with a larger lateral shrinkage to obtain the corrected arc starting coordinates. After positioning the subsequent weld passes according to the corrected arc starting coordinates, welding continues. This solution can dynamically correct the arc starting position according to the actual shrinkage distribution, compensate for the lateral shrinkage of welding in advance, and reduce the overall dimensional deviation of large box segments.

[0016] The technical effects and advantages provided by the present invention in the above technical solution are as follows: The large container is divided into multiple segments based on the projection of the transverse bulkhead and container guide rail centerlines. The guide rail base elevation, bulkhead verticality tolerance, and strong beam position of each segment are extracted to generate a segment construction control parameter set, ensuring that each segment obtains control data corresponding to its design state. After the plates are assembled into a container with open ports, support frames are installed at the open ports. The support point heights of the support frames are adjusted using the segment construction control parameter set. During adjustment, the guide rail base elevation is read from the segment construction control parameter set, forming a height trend sequence along the width direction of the open port. Starting from the central measurement section, the support points are adjusted to the corresponding relative height. Then, starting from the initial section, adjustments are made section by section to both sides until the current section's support point height lies on the extension line connecting the heights of adjacent adjusted section support points. This creates a continuous transition between the support point heights at the open ports and the guide rail base elevation and bulkhead verticality tolerance. The support frame provides adjustable constraints along the circumferential distribution on the edges of the port plate array, suppressing localized depressions and torsion during assembly and welding. This method differs from the general-purpose jig fixed support. It establishes a limit state at the opening port that corresponds to the segment construction control parameters, reduces the cross-sectional deformation in the port area, reduces the transmission of subsequent welding deformation to the guide rail base and bulkhead interface, and improves the compliance of the guide rail base elevation and bulkhead verticality.

[0017] When welding the limiting box body symmetrically with the longitudinal mid-section as the plane, the transverse shrinkage is measured after each weld pass. This transverse shrinkage is then converted into the transverse offset of the arc starting point for the next weld pass, and subsequent weld passes are positioned according to this offset. During measurement, shrinkage measurement points are arranged along the length of the weld pass, and the distance between the plate edges on both sides of the weld pass is read to form a sequence of transverse shrinkage. During conversion, the boundary of the measurement interval with the largest transverse shrinkage is used as the reference position of the arc starting point. It is moved one preset step length towards the unwelded side, and then offset towards the adjacent measurement interval with a larger transverse shrinkage to obtain the corrected arc starting coordinates. Subsequent weld passes are positioned according to the corrected arc starting coordinates and continue welding, so that the position of the arc starting point is dynamically adjusted according to the measured shrinkage of the previous weld pass. This process replaces the method of reserving a uniform shrinkage amount based on empirical values, so that the right and left halves of the transverse weld maintain transverse position matching during alternating welding, reducing transverse misalignment and residual stress between adjacent weld passes, and improving the overall alignment and interface size consistency of large box body segments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a flowchart of the method for constructing large container ship sections. Figure 2 This is a flowchart of the process for dividing large container ship hull sections and extracting construction control parameters; Figure 3 This is a flowchart of a process for adjusting the height of the support points of a support frame using a set of control parameters for segmental construction to obtain a limiting box. Figure 4 This is a schematic diagram showing the lateral shrinkage of the weld bead of the limiting box and the lateral offset of the arc starting point. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] See Figure 1 This invention provides a method for constructing large container ship hull sections, comprising: acquiring a three-dimensional design model of the large container ship hull; dividing the large hull into multiple hull sections according to the projection of the transverse bulkhead and the centerline of the container guide rail; extracting the guide rail base elevation, bulkhead verticality tolerance, and strong beam position of each hull section to generate a set of section construction control parameters; dividing each hull section into plate rows according to the set of section construction control parameters, determining the beveling direction according to the rolling direction of each plate row, and generating a plate row assembly sequence; assembling each plate row into a hull with an open port according to the plate row assembly sequence; installing a support frame at the open port; adjusting the support point height of the support frame using the set of section construction control parameters to obtain a limited hull; symmetrically welding the limited hull with the longitudinal midsection as the symmetrical surface; measuring the transverse shrinkage after each weld pass; converting the transverse shrinkage into the transverse offset of the starting point of the next weld pass; completing subsequent weld passes according to the transverse offset of the starting point to form large hull sections.

[0022] In specific implementation, please refer to Figure 2When dividing a large container ship into multiple segments based on the projection of the transverse bulkhead and the centerline of the container rails, the plane containing the transverse bulkhead and the centerline of the container rails are read from the 3D design model of the large container ship. The projection line of the centerline of the container rails onto the plane containing the transverse bulkhead is used as the segment division generatrix. The projection direction is the normal direction of the plane containing the transverse bulkhead. Projecting along the segment division generatrix towards the outer plate of the large container ship results in a closed segmentation loop. During the projection process, the segment division generatrix is ​​extended point by point along the surface of the outer plate of the large container ship. When the segment division generatrix intersects with the outer plate of the large container ship, the intersection point is recorded, and all intersection points are connected sequentially to form a closed segmentation loop. When cutting the 3D design model of the large container ship along the closed segmentation loop, the segmentation operation is performed in the 3D design model with the closed segmentation loop as the boundary, so that the large container ship is separated into multiple segments. Each segment is assigned a segment number according to the cutting order, with the segment number increasing sequentially from one end of the large container ship to the other. A table mapping segment numbers to interface coordinates is generated. The interface coordinates contain a set of 3D coordinate points for each box segment at the closed segmentation ring. Each segment number in the table uniquely corresponds to a set of interface coordinates, which are used for position alignment during subsequent box segment assembly. In specific implementation, when extracting the guide rail base elevation, bulkhead verticality tolerance, and strong beam position for each box segment, the rib position and deck level of each box segment's guide rail base are read from the 3D design model. The rib position is the longitudinal structural position number of the hull, and the deck level is the deck level where the guide rail base is located. The guide rail base elevations are arranged into an array according to the rib position. Each element in the array corresponds to the guide rail base elevation value at a rib position, and the elevation value is represented by the vertical distance based on the large box baseline. The bulkhead verticality tolerance is read and associated with the corresponding box segment interface. The bulkhead verticality tolerance is the allowable deviation value of the transverse bulkhead in the vertical direction, read from the tolerance annotation of the 3D design model. The read bulkhead verticality tolerance is associated with the corresponding box segment interface, and the associated bulkhead verticality tolerance serves as the verticality control benchmark for the box segment interface. When converting the position of the strong crossbeam to relative coordinates with the center point of the box segment as the origin, the position of the strong crossbeam is represented by global coordinates in the 3D design model. The center point of the box segment is the geometric center of the box segment in the length, width, and height directions. The relative coordinates are calculated as follows: Equation 1: in, The transverse relative coordinates of the strong crossbeam position in the local coordinate system of the box girder segment are given. This represents the longitudinal relative coordinate of the strong crossbeam position in the local coordinate system of the box girder segment. The vertical relative coordinates of the strong crossbeam position in the local coordinate system of the box segment; Let be the horizontal coordinate of the strong crossbeam position in the global coordinate system of the 3D design model. This represents the longitudinal coordinate of the strong crossbeam's position in the global coordinate system of the 3D design model. The vertical coordinates of the strong crossbeam position in the global coordinate system of the three-dimensional design model; Let be the lateral coordinate of the center point of the box segment in the global coordinate system of the 3D design model. Here is the longitudinal coordinate of the center point of the box segment in the global coordinate system of the 3D design model. This represents the vertical coordinates of the center point of the box segment in the global coordinate system of the 3D design model. The calculated relative coordinates of the strong crossbeam positions, along with the base elevation array and bulkhead verticality tolerance, are combined into a segment construction control parameter set. This set is a structured dataset containing the base elevation array, bulkhead verticality tolerance, and relative coordinates of the strong crossbeams for each box segment. The segment construction control parameter set is used for subsequent plate division, support frame height adjustment, and welding offset control.

[0023] In practical implementation, when dividing each box segment into plate rows according to the segment construction control parameter set, the longitudinal stiffener spacing of each box segment is read from the 3D design model. The longitudinal stiffener spacing is the lateral distance between adjacent longitudinal stiffeners on the bottom plate of the box segment. Using the longitudinal stiffener spacing as the dividing width, the bottom plate, side plate, and top plate of the box segment are sequentially divided into multiple plate rows. For the bottom plate of the box segment, the bottom plate is divided into multiple bottom plate rows along the width direction of the box segment using the longitudinal stiffener spacing as the dividing width; for the side plate of the box segment, the side plate is divided into multiple side plate rows along the height direction of the box segment using the longitudinal stiffener spacing as the dividing width; for the top plate of the box segment, the top plate is divided into multiple top plate rows along the width direction of the box segment using the longitudinal stiffener spacing as the dividing width. The plate row width at the edge of the box segment is adjusted according to the remaining width of the box segment, and the adjusted plate row width is not less than half of the longitudinal stiffener spacing.

[0024] Read the rolling direction arrows marked on each plate row. These arrows serve as attribute labels for the plate rows in the 3D design model, pointing in the direction the plate row will extend during rolling. After reading the rolling direction arrows, set the bevel direction of the plate row to be perpendicular to the rolling direction arrows. The bevel direction is the orientation of the cut bevel at the edge of the plate row where welding is to be performed.

[0025] Compare the rolling direction arrow with the length direction of the box segment. Define the length direction of the box segment as the direction of its longitudinal centerline. Project the rolling direction arrow onto the plane containing the box segment and calculate the angle between the rolling direction arrow and the length direction of the box segment. The angle is calculated as follows: Equation 2. in, Let be the directional angle of the p-th plate column. Let the rolling direction arrow vector be the p-th plate column. Let be the direction vector of the box segment length. Represents the dot product of vectors. Let be the modulus of the rolling direction arrow vector of the p-th plate column. Let be the magnitude of the direction vector of the box segment length. The value range is from 0° to 90°.

[0026] Direction angle markings are generated based on the included direction angle. Each 15° interval is designated as a marking interval. Plate rows with included direction angles greater than or equal to 0° and less than or equal to 15° are marked as the first direction mark; those with included direction angles greater than 15° and less than or equal to 30° are marked as the second direction mark; those with included direction angles greater than 30° and less than or equal to 45° are marked as the third direction mark; those with included direction angles greater than 45° and less than or equal to 60° are marked as the fourth direction mark; and those with included direction angles greater than 60° and less than or equal to 90° are marked as the fifth direction mark. The 15° intervals are based on the fact that for every 15° increase in the angle between the rolling direction of the plate row and the length direction of the box section, a distinguishable step change occurs in the effect of the change in the fiber direction of the plate row on the welding bevel direction.

[0027] Plate rows with the same directional angle markings are grouped into the same assembly batch. An assembly batch is the unit for grouping plate rows during assembly. All plate rows marked with the first directional angle marking are grouped into the first assembly batch; all plate rows marked with the second directional angle marking are grouped into the second assembly batch; all plate rows marked with the third directional angle marking are grouped into the third assembly batch; all plate rows marked with the fourth directional angle marking are grouped into the fourth assembly batch; and all plate rows marked with the fifth directional angle marking are grouped into the fifth assembly batch. If a plate row with a certain directional angle marking does not exist in a box segment, the corresponding assembly batch is empty.

[0028] The assembly sequence of plates is generated by arranging them from the center outwards according to assembly batches. For the bottom plate of the box segment, using the center line of the bottom plate as the baseline, the bottom plates from the first assembly batch are arranged at the center line position, the bottom plates from the second assembly batch are arranged on both sides of the bottom plates from the first assembly batch, and the bottom plates from the third assembly batch are arranged outside the bottom plates from the second assembly batch, and so on outwards. For the side plates of the box segment, the center line of the side plate height is used as the baseline, and they are arranged in the same way. For the top plates of the box segment, the center line of the top plate is used as the baseline, and they are arranged in the same way. After the arrangement is completed, the assembly sequence of plates is generated. Each element in the assembly sequence includes a plate identifier, the assembly batch to which the plate belongs, and the positional order of the plate in the box segment. The assembly sequence of plates serves as the execution order for subsequent plate assembly operations.

[0029] In practice, when assembling the plate rows into a box with open ports according to the assembly sequence, the first plate row in the sequence is placed on the jig reference surface. The four edges of the first plate row are aligned with the positioning lines on the jig reference surface, and temporary positioning blocks are installed at the four corners of the first plate row. These temporary positioning blocks are fitted against the outer edges of the corners of the first plate row and fixed to the jig reference surface with bolts. Subsequent plate rows are then attached piece by piece along the longitudinal edge of the jig reference surface. For each subsequent plate row attached, a tack weld is performed on the butt joint between this subsequent plate row and the already positioned plate rows. The tack weld is performed at fixed intervals along the length of the butt joint, the interval determined by the butt joint length and the plate row thickness. After all subsequent plate rows are in place, the edge of the plate row on the stern side of the box segment is cut, with the cutting line extending along the end contour of the plate row on the stern side of the box segment, forming the open port. The edge of the opening port is the end face of the stern plate array of the box segment formed after cutting. In specific implementation, when installing the support frame at the opening port, multiple vertical support rods are set at intervals along the circumferential edge of the opening port. The interval of the vertical support rods is determined according to the length of the circumferential edge of the opening port and the load-bearing capacity of the vertical support rods. The vertical support rods are perpendicular to the plane where the opening port is located. Diagonal braces are set at the corners of the opening port. One end of the diagonal brace is connected to the adjacent vertical support rod, and the other end of the diagonal brace is connected to the edge of the plate array at the corner of the opening port. The tops of each vertical support rod are connected sequentially by a transverse connecting rod to form a ring support frame. The tops of the transverse connecting rods and the vertical support rods are detachably connected. The transverse connecting rods are arranged along the circumferential direction of the opening port, and the ring support frame surrounds the opening port. An adjustment gap is maintained between the ring support frame and the edge of the plate array of the opening port. The adjustment gap is determined by the following formula 3: in, For adjusting the gap, the unit is millimeters; The gap coefficient is dimensionless and is used to adjust the gap. The thickness of the plate column at the opening port is in millimeters. The value range is from 0.2 to 0.5. The adjustment gap is determined by selecting a value between 0.2 and 0.5 based on the plate thickness at the opening port and the adjustable range of the adjusting screw on the vertical support rod. The selection principle is that the adjustment gap should not exceed the maximum adjustment stroke of the adjusting screw on the vertical support rod, and the adjustment gap should be greater than zero. Each vertical support rod is equipped with an adjusting screw, and the height of the top of the vertical support rod is changed by rotating the adjusting screw. When the height of the top of the vertical support rod changes, the transverse connecting rod connected to the top of the vertical support rod moves synchronously with the top of the vertical support rod. The adjustment gap between the annular support frame and the edge of the plate array at the opening port is adjusted by raising or lowering the top of the vertical support rod.

[0030] In specific implementation, please refer to Figure 3 When adjusting the support point height of the support frame to obtain the limiting box using the segmental construction control parameter set, the guide rail base elevation is read from the segmental construction control parameter set. The segmental construction control parameter set contains a base elevation array, where each element corresponds to a guide rail base elevation value at a rib. The guide rail base elevation value is represented by the vertical distance from the baseline of the large box. The guide rail base elevations are sorted into a height trend sequence according to the width direction of the opening port. The width direction of the opening port is the edge direction extending along the width direction of the box segment in the circumferential edge of the opening port. The guide rail base elevation values ​​at different positions in the width direction of the opening port are arranged from one side of the opening port to the other according to the coordinates of the width direction of the opening port, forming a height trend sequence.

[0031] The central measurement section of the opening port is selected as the starting section. The central measurement section is the measurement section perpendicular to the length direction of the opening port at the center of the opening port's width direction. Each support point on the starting section is adjusted to its relative height corresponding to the height trend sequence. The support points on the starting section are distributed along the width direction of the opening port, and the coordinates of each support point in the width direction correspond to its position coordinates in the height trend sequence. The guide rail base elevation value corresponding to the support point's position in the height trend sequence is used as the relative height setting value for that support point. The top height of the vertical support rod is adjusted to this relative height setting value by rotating the adjusting screw on the vertical support rod of the support frame.

[0032] Starting from the initial section, adjust each support point section by section along both sides of the opening port. Both sides of the opening port include the direction from the central measurement section toward the first end of the opening port and the direction toward the second end of the opening port along the length of the opening port. Each section to be adjusted corresponds to one measurement section on the opening port, and the spacing between adjacent measurement sections is consistent with the spacing between adjacent vertical support rods on the support frame along the length of the opening port. For the current section, adjust the support point height of the current section to the extension line of the line connecting the support point heights of adjacent adjusted sections. Adjacent adjusted sections include the two adjusted sections closest to the current section along the adjustment direction. The support point height of adjacent adjusted sections is the support point height value that has already been adjusted. The extension line is obtained by linearly extending the line connecting the support point heights of adjacent adjusted sections along the adjustment direction. When there are already two adjacent adjusted sections along the adjustment direction, i.e., the first... The first section and the first The support point height adjustment has been completed for all sections, and the current section is... The support point height of each section is calculated according to the following formula 4: in, For the current number The height of the support points for each cross section is in millimeters. In order to be consistent with the current number The adjacent cross sections that have been adjusted The height of the support points for each cross section is in millimeters. In order to be with the first The adjacent cross sections that have been adjusted The height of the support points for each cross section is in millimeters. For the current number The coordinates of the cross section along the length of the opening port are shown in millimeters. For the first The coordinates of the cross section along the length of the opening port are shown in millimeters. For the first The coordinates of a cross section along the length of the opening port, in millimeters. , , The coordinates are obtained by measuring the distance from each cross-section to the first end of the opening port, starting from the baseline along the length direction of the opening port edge. When the cross-section is located on the side of the initial cross-section facing the first end of the opening port, the length direction coordinate is taken as a positive value; when the cross-section is located on the side of the initial cross-section facing the second end of the opening port, the length direction coordinate is taken as a negative value. and The method of obtaining is to read the first The first section and the first Recorded values ​​of the height of the support points that have been adjusted in each section.

[0033] Calculate the current number according to the above formula. After determining the support point height of the current section, rotate the current section... Adjust the adjusting screws corresponding to the vertical support rods on each cross-section to adjust the top height of the vertical support rods to the calculated support point height. Complete the current [section / section]. After adjusting the height of all support points of each section, the current section will be... Each section is marked as adjusted, and the machine moves along the adjustment direction to the next section, continuing to adjust the support point height of the next section until the support point heights of all sections on both sides of the opening are adjusted. The box after the support point height adjustment is completed is the limit box.

[0034] In practice, when welding the limiting box body symmetrically with its longitudinal mid-section as the reference, corresponding weld mirror points are marked on both sides of the longitudinal mid-section of the limiting box body. The longitudinal mid-section of the limiting box body is a vertical plane passing through the geometric center of the limiting box body along its length. When marking the weld mirror points, using the longitudinal mid-section of the limiting box body as a reference, after determining the arc initiation position of the weld segment on one side of the longitudinal mid-section of the limiting box body, a mirror point is marked on the other side of the longitudinal mid-section of the limiting box body at a position symmetrical to the arc initiation position of the weld segment. The line connecting the mirror point and the corresponding arc initiation position of the weld segment is perpendicular to the longitudinal mid-section of the limiting box body. Marking can be done by using a scribing needle to draw crosshairs on the surface of the limiting box body plate; the intersection of the crosshairs is the weld mirror point.

[0035] Each transverse weld is divided into a right half and a left half, located on either side of the longitudinal mid-section. The right half is located on the right side of the longitudinal mid-section of the locating box, and the left half is located on the left side. The right and left half welds are separated by the longitudinal mid-section of the locating box, and their lengths are the same.

[0036] Weld the starting segment of the right half of the weld, then weld the corresponding starting segment of the left half. The starting segment of the right half is the section closest to the end of the transverse weld in the right half, and the corresponding starting segment of the left half is the section in the left half that is symmetrical to the starting segment of the right half about the longitudinal mid-section of the limiting box. Complete the entire transverse weld in an alternating order between the right and left half welds; that is, after completing the first segment of the right half weld, complete the first segment of the left half weld, then complete the second segment of the right half weld, then complete the second segment of the left half weld, and so on, until the entire transverse weld is completed. Before starting the arc for each weld segment, align the welding torch axis with the mirror mark line of that weld segment. The mirror mark line is a straight line starting from the mirror point of that weld segment and perpendicular to the longitudinal mid-section of the limiting box. Start the arc after the welding torch axis coincides with the mirror mark line.

[0037] In practice, after each weld bead is measured for lateral shrinkage, multiple shrinkage measurement points are placed at predetermined intervals along the length of that weld bead after the weld bead has cooled to a set temperature. The set temperature is the ambient temperature plus 20°C, and the ambient temperature is read by a thermometer placed near the weld bead and not affected by welding heat. The predetermined interval is 500 mm. This predetermined interval is selected based on the fact that the measurement interval length obtained by dividing the total weld bead length by the number of shrinkage measurement points is not greater than 550 mm and not less than 450 mm, to ensure that the change in lateral shrinkage along the length of the weld bead can be effectively distinguished.

[0038] At each shrinkage measurement point, place a width measuring caliper across the weld bead and read the distance between the two sides of the plate edge of the weld bead. The fixed measuring jaw of the width measuring caliper is in contact with one side of the plate edge of the weld bead, and the movable measuring jaw of the width measuring caliper is in contact with the other side of the plate edge of the weld bead. Read the distance value with an accuracy of 0.01 mm.

[0039] The difference between the spacing values ​​of two adjacent shrinkage measurement points is processed to obtain the lateral shrinkage sequence for each measurement interval. During the difference processing, the spacing value of the previous shrinkage measurement point is subtracted from the spacing value of the subsequent shrinkage measurement point. A positive difference is recorded as positive, and a negative difference is recorded as zero. A measurement interval is the weld bead segment between two adjacent shrinkage measurement points. The measurement intervals are arranged sequentially along the weld bead length, and each element in the lateral shrinkage sequence corresponds to the lateral shrinkage of one measurement interval.

[0040] In practice, when converting the lateral shrinkage amount into the lateral offset of the starting point of the next weld pass, multiple measurement intervals are selected along the length of the completed weld pass, and the lateral shrinkage amount corresponding to each measurement interval is recorded. The completed weld pass refers to the weld pass that has just been welded and whose lateral shrinkage amount has been measured. The multiple measurement intervals refer to all measurement intervals in the lateral shrinkage amount sequence.

[0041] The boundary of the measurement interval with the largest lateral shrinkage is used as the reference position for the arc initiation point. The measurement interval with the largest lateral shrinkage is the measurement interval corresponding to the element with the largest value in the lateral shrinkage sequence. The reference position for the arc initiation point is a boundary line of this measurement interval near the unwelded side, which is the side of a completed weld pass that has not yet been welded for the next weld pass.

[0042] The reference position of the arc initiation point is moved along the length of the completed weld bead towards the unwelded side by a preset step length. The preset step length is equal to 500 mm, which is consistent with the predetermined interval between two adjacent shrinkage measurement points. After the movement, the longitudinal position of the arc initiation point is obtained.

[0043] The moved position is offset towards the adjacent measurement interval with the larger lateral shrinkage to obtain the corrected arc-starting coordinates. The adjacent measurement intervals are the two measurement intervals adjacent to the measurement interval with the largest lateral shrinkage along the weld length direction. The adjacent measurement interval with the larger lateral shrinkage is the measurement interval with the larger lateral shrinkage value among these two adjacent measurement intervals. The offset amount is calculated using the following formula 5: in, The unit is millimeters, which is used to correct the offset of the arc initiation coordinates relative to the reference position of the arc initiation point in the transverse direction of the weld bead. The measurement range with the largest lateral shrinkage corresponds to the lateral shrinkage amount, in millimeters. The lateral shrinkage is the amount of lateral shrinkage corresponding to the adjacent measurement interval with the larger lateral shrinkage, in millimeters; The coefficient representing the influence of the maximum lateral contraction is dimensionless. This is the influence coefficient of the difference in lateral shrinkage, which is dimensionless.

[0044] The value is 0.45. The value is 0.25. and The selection criteria are as follows: for marine steel plates with a thickness of 20 mm to 25 mm, the transverse shrinkage corresponding to the measurement range with the largest transverse shrinkage is usually between 0.8 mm and 1.5 mm, and the difference in transverse shrinkage is usually between 0.2 mm and 0.6 mm. The values ​​calculated based on these criteria are... It should be in the range of 0.45 mm to 0.85 mm, and not exceed one-third of the transverse width of a completed weld bead.

[0045] The corrected arc-starting coordinates include corrected longitudinal and lateral coordinates. The corrected longitudinal coordinate is the longitudinal coordinate of the arc-starting reference position after moving it one preset step length along the length of the completed weld bead towards the unwelded side. The corrected lateral coordinate is the coordinate of the arc-starting reference position in the lateral direction of the weld bead plus an offset. The horizontal coordinates obtained later.

[0046] After positioning the subsequent weld bead according to the corrected arc-starting coordinates, continue welding. The subsequent weld bead is the next weld bead to be welded after the previous weld bead has been completed. When positioning the subsequent weld bead, the corrected arc-starting longitudinal coordinates and the corrected arc-starting transverse coordinates are used as the positioning basis for the arc-starting point of the subsequent weld bead. After aligning the welding torch axis with the corrected arc-starting coordinate point, start the arc and continue welding the subsequent weld bead in an alternating symmetrical welding sequence.

[0047] See Figure 4 In the figure, the horizontal axis represents the weld length, ranging from 0 mm to 4000 mm, and the vertical axis represents the lateral shrinkage and the lateral offset of the arc initiation point, all in millimeters. The solid line represents the lateral shrinkage of the weld in the right half of the limiting box, the dashed line represents the lateral shrinkage of the weld in the left half, the dotted line represents the lateral offset of the arc initiation point, and the red dotted line marks the measurement area with the largest lateral shrinkage.

[0048] As shown in the figure, the transverse shrinkage curve of the left half of the weld initially rises slowly, then increases significantly in the range of approximately 1000 mm to 2000 mm, reaching a peak of about 1.45 mm, and reaching the maximum shrinkage range at 2000 mm. The transverse shrinkage curve of the right half of the weld shows a symmetrical trend corresponding to the left half, decreasing from 4000 mm to 2000 mm, with a maximum shrinkage of about 1.4 mm, and reaching its peak at 2000 mm, just like the left half.

[0049] The lateral offset curve of the arc starting point is located in the lower middle of the figure, showing a symmetrical convex trend. Its maximum offset is about 0.6 mm, and the range is concentrated in the middle of the weld bead, about 2000 mm. The offset increases from both ends of the weld bead toward the middle and then decreases, reflecting the adjustment range of the arc starting point when welding symmetrically.

[0050] The red dashed line marks the maximum lateral shrinkage measurement range located 2000 mm from the middle of the weld bead. This position corresponds to the peak shrinkage in the left and right halves of the weld and serves as the reference position for the arc initiation point of subsequent weld bead passes. Furthermore, the adjustment of the lateral offset of the arc initiation point follows the data from the maximum lateral shrinkage range and its adjacent measurement ranges. By correcting the offset, the positioning of the arc initiation point is optimized, ensuring the balance and symmetry of lateral shrinkage during welding.

[0051] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for constructing large container ship hull sections, characterized in that, The method includes: A three-dimensional design model of the large container ship hull is obtained. Taking the plane where the transverse bulkhead is located as the reference, the center line of the container guide rail is projected onto the plane where the transverse bulkhead is located. The large container hull is divided into multiple hull segments using the projection line obtained by projection as the dividing generatrix. The guide rail base elevation, bulkhead verticality tolerance and strong crossbeam position of each hull segment are extracted to generate a set of segment construction control parameters. Based on the segment construction control parameter set, each box segment is divided into plate rows, and the bevel direction is determined according to the rolling direction of each plate row to generate the plate row assembly sequence; Assemble each plate column into a box with an open port according to the plate column assembly sequence, install a support frame at the open port, and adjust the support point height of the support frame using the segment construction control parameter set to obtain a limited box; The limiting box is symmetrically welded with the longitudinal mid-section as the symmetrical surface. After each weld pass is completed, the lateral shrinkage is measured and converted into the lateral offset of the arc starting point of the next weld pass. The subsequent weld passes are completed according to the lateral offset of the arc starting point to form a large box segment.

2. The method for constructing large container ship hull sections according to claim 1, characterized in that, The step of projecting the center line of the container guide rail onto the plane of the transverse bulkhead, using the projected line as the dividing generatrix, and then dividing the large container into multiple container segments includes: The projection line of the center line of the container guide rail onto the plane of the transverse bulkhead is used as the segment division generatrix. Extend the segment dividing busbar point by point along the outer panel surface of the large box, record all intersection points between the segment dividing busbar and the outer panel of the large box, and connect all intersection points in sequence to obtain a closed dividing loop. The three-dimensional design model of the large box is cut along the closed segmentation ring, and each box segment is assigned a segment number according to the cutting order, generating a correspondence table between segment number and interface coordinate.

3. The method for constructing large container ship hull sections according to claim 1, characterized in that, The steps of extracting the guide rail base elevation, bulkhead verticality tolerance, and strong crossbeam position for each box segment to generate a set of segment construction control parameters include: Read the rib position and deck level of the guide rail base of each box segment from the three-dimensional design model, and arrange the guide rail base elevations into an array according to the rib position. Read the bulkhead verticality tolerance and associate it with the corresponding box segment interface; The position of the strong crossbeam is converted into relative coordinates with the center point of the box segment as the origin, and the relative coordinates are combined with the base elevation array and the bulkhead verticality tolerance to form a segment construction control parameter set.

4. The method for constructing large container ship hull sections according to claim 1, characterized in that, The steps of dividing each box segment into plate rows according to the segment construction control parameter set, determining the bevel direction according to the rolling direction of each plate row, and generating the plate row assembly sequence include: Using the longitudinal rib spacing in each box segment as the dividing width, the bottom plate, side plate, and top plate of the box segment are sequentially divided into multiple plate rows; Read the rolling direction arrow marked on each plate column, compare the rolling direction arrow with the length direction of the box segment, and generate a direction angle mark; Plates with the same directional angle markings are grouped into the same assembly batch. Using the center line of the bottom plate, the center line of the side plate height, and the center line of the top plate of the box segment as baselines, the plates in the first assembly batch are arranged at the corresponding center line positions. The plates in the second assembly batch are arranged on both sides of the plates in the first assembly batch. The plates in the third assembly batch are arranged outside the plates in the second assembly batch. This process is repeated to generate the plate assembly sequence.

5. The method for constructing large container ship hull sections according to claim 1, characterized in that, The step of assembling the plates into a box with open ports according to the plate assembly sequence includes: Place the first plate in the assembly sequence on the reference surface of the jig, and install temporary positioning blocks at the four corners of the plate. The subsequent plate rows are attached one by one along the longitudinal edge of the reference surface of the jig, and the butt joint between the plate row and the already positioned plate row is tack welded after each plate row is attached. After all the plates are in place, the edge of the plate array on the stern side of the box segment is cut to form the opening port.

6. The method for constructing large container ship hull sections according to claim 1, characterized in that, The step of installing the support frame at the opening port includes: Multiple vertical support rods are spaced apart along the circumferential edge of the opening port, and diagonal bracing rods are provided at the corners of the opening port; The tops of each vertical support rod are connected sequentially by horizontal connecting rods to form a ring support frame; An adjustment gap is maintained between the annular support frame and the edge of the plate array at the opening port, and an adjustment screw is provided on each vertical support rod to change the top height of the vertical support rod.

7. The method for constructing large container ship hull sections according to claim 1, characterized in that, The step of adjusting the support point height of the support frame using the segment construction control parameter set to obtain the limiting box includes: The guide rail base elevation is read from the segment construction control parameter set, and the guide rail base elevation is sorted into a height trend sequence according to the width direction of the opening port; Select the central measurement section of the opening port as the starting section, and adjust each support point on the starting section to a relative height corresponding to the height trend sequence; Starting from the initial section, along the length direction of the opening port towards the first end and towards the second end, the support points are adjusted section by section according to the spacing between adjacent measurement sections, so that the height of the support point of the current section is located on the extension line of the line connecting the heights of the support points of adjacent adjusted sections. After the support point height adjustment is completed, the limiting box is obtained.

8. The method for constructing large container ship hull sections according to claim 1, characterized in that, The step of symmetrically welding the limiting box body with the longitudinal mid-section as the symmetrical plane includes: Mark the corresponding weld mirror points on both sides of the longitudinal mid-section of the limiting box, and divide each transverse weld into the right half weld and the left half weld located on the left and right sides of the longitudinal mid-section. First weld the starting section of the right half of the weld, then weld the corresponding starting section of the left half of the weld. Complete the entire transverse weld by alternating between the right and left halves of the weld, and align the welding torch axis with the mirror mark line of each weld segment before igniting the arc.

9. The method for constructing large container ship hull sections according to claim 1, characterized in that, The step of measuring the lateral shrinkage after each weld pass includes: After a weld bead cools to a set temperature, multiple shrinkage measurement points are set at predetermined intervals along the length of the weld bead. Place a width measuring caliper across the weld bead at each shrinkage measurement point and read the distance between the plate edges on both sides of the weld bead. The difference between the distance values ​​of two adjacent shrinkage measurement points is processed to obtain the transverse shrinkage sequence of each measurement interval.

10. The method for constructing large container ship hull sections according to claim 1, characterized in that, The step of converting the lateral shrinkage amount into the lateral offset of the arc starting point for the next weld pass, and completing the subsequent weld pass according to the lateral offset of the arc starting point, includes: In a completed weld bead, select multiple measurement intervals along the length of the weld bead and record the lateral shrinkage amount corresponding to each measurement interval; The boundary of the measurement range with the largest lateral contraction is taken as the reference position of the arc starting point; The reference position of the arc starting point is moved by a preset step length along the length of the completed weld bead towards the unwelded side, and the moved position is offset towards the adjacent measurement interval with a larger lateral shrinkage to obtain the corrected arc starting coordinates. After positioning the subsequent weld passes according to the corrected arc-starting coordinates, continue welding.

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