A method for automatic 2D hull lines division and pressure grid mapping for calculating whole ship slamming loads

Abstract

The application provides a two-dimensional line automatic division and pressure grid mapping method for calculating whole-ship slamming load. Based on a hull shell grid model provided by a user, according to a longitudinal position of a set two-dimensional cutting section and a cutting surface inclination angle obtained through ship wave relative motion (or a directly specified manner), a two-dimensional section line cutting, fairing and optimization algorithm in the application is used to obtain a two-dimensional section line of the whole ship for calculating the slamming load, so that the influence of the ship speed on the slamming load can be considered; the slamming pressure nodes calculated on the two-dimensional slamming section line are projected onto the real ship body surface, so that the ship body slamming pressure can be integrated on the real ship body shell, and the three-dimensional distribution of the slamming pressure on the ship body surface can be displayed.

Description

Technical Field

[0001] This invention belongs to the field of ship slamming load, specifically relating to a two-dimensional automatic profile division and pressure grid mapping method for calculating the slamming load of the entire ship. Background Technology

[0002] With the rapid development of the shipping industry, modern ships are gradually moving towards larger dimensions, higher speeds, and larger outward-flaring bows. In high sea states, this can easily lead to slamming due to the relative motion of large waves, resulting in high-frequency flutter responses that increase the amplitude and total number of nonlinear wave loads on the hull. This poses a threat to the structural strength of ships with large outward-flaring bows and has attracted great attention from the maritime community.

[0003] The most widely used method for predicting ship flutter response under high sea states is the seakeeping prediction method based on potential flow theory, combined with a fast two-dimensional slamming load calculation method, to achieve rapid prediction of ship slamming flutter. The slamming load calculation requires a good balance between computational efficiency, accuracy, and stability. Currently, fast calculation methods for flutter response prediction, such as CCS Classification Society's COMPASS-WALCS-NE software and Seoul National University's WISH software, essentially employ a "slicing method" for slamming load calculation. This involves dividing the hull longitudinally into several transverse slices and integrating the calculated slamming pressure along these slices to obtain the overall slamming load of the hull.

[0004] The slamming load calculated using the above method does not exhibit longitudinal curvature variation within a single slice. However, for areas with significant longitudinal curvature variations, such as the bow and stern, these changes in curvature will cause the slamming load to have a longitudinal component. Furthermore, when the ship is traveling forward, the pre-set slamming slice direction cannot match the actual water entry direction. To accurately and efficiently calculate the slamming load experienced by the entire ship, improvements are needed in the following two aspects:

[0005] 1) The direction of the two-dimensional slam slice should be kept as consistent as possible with the direction of the relative velocity of the synthesized ship wave;

[0006] 2) The mesh used for integrating slamming pressure should fit the original three-dimensional curved surface shape of the hull as closely as possible.

[0007] Of the two aspects mentioned above, the first is to improve the calculation accuracy of slamming pressure, and the second is to improve the calculation accuracy of the overall ship pressure integral. Summary of the Invention

[0008] The purpose of this invention is to provide a two-dimensional automatic profile division and pressure grid mapping method for calculating the slamming load of a ship.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A method for automatically generating two-dimensional profiles and mapping pressure meshes for calculating the slamming load of a ship, the specific steps of which are as follows:

[0011] Step 1: Use equally spaced horizontal intersection lines to simplify the description of the three-dimensional hull features;

[0012] Step 1.1: Based on the hull outer surface mesh file provided by the user, cut the hull outer surface mesh with horizontal planes distributed at equal intervals along the height to obtain all the cutting points;

[0013] Step 1.2: Based on the coordinate information of the cutting points obtained in Step 1.1, the cutting points are numbered and sorted using the feature point spacing sorting algorithm to obtain an ordered arrangement of points that can form a line from the stern to the bow or from the bow to the stern, thus obtaining a discrete point array describing the horizontal intersection information.

[0014] Step 2: Extraction of the original 2D slamming profile contour;

[0015] Step 2.1: At the longitudinal position specified by the user, based on the direction of the relative motion velocity of the ship wave at the given position point, or directly provided by the user, obtain the longitudinal angle of the cross section used to cut the horizontal intersection line in Step 1.

[0016] Step 2.2: Based on the inclination information of the cross section obtained in Step 2.1 and the specified longitudinal position information, intersect the set cutting cross section with the above-mentioned horizontal intersection line to obtain a discrete point array describing the original two-dimensional slap section.

[0017] Step 3: Smoothing and optimizing the profile contour;

[0018] Step 3.1: Based on the original banging profile discrete points extracted in Step 2, the original nodes are converted into a series of nodes distributed along the profile with equal arc lengths using the equal arc length method;

[0019] Step 3.2: Perform cumulative chord length cubic spline interpolation and refinement on the equal arc length nodes obtained in Step 3.1 to obtain the coordinates and slope information of the curve;

[0020] Step 3.3: Filter the interpolated and encrypted curves in Step 3.2, identify the concave segments, and replace the concave segments with inclined straight lines and end arcs to make the two-dimensional profile monotonically increasing, thus obtaining a two-dimensional calculation profile that meets the requirements of impact pressure calculation.

[0021] Step 4: Projection of pressure nodes on the impact section line onto the three-dimensional hull shell;

[0022] Step 4.1: For the two-dimensional slammed section in Step 3, select the projection center feature point based on the coordinates of the bottom and top nodes of the slammed section;

[0023] Step 4.2: Based on the pressure nodes on the two-dimensional impact section line connecting the projection center point and the pressure nodes, calculate the intersection of the projection line and the original cutting section line in Step 2 to obtain the pressure projection points distributed on the three-dimensional outer shell of the ship.

[0024] Step 4.3: Based on the coordinates of the pressure projection points distributed on the three-dimensional outer shell of the hull obtained in Step 4.2, interconnect the projection points corresponding to adjacent cutting lines to obtain the pressure integral grid distributed on the three-dimensional outer shell of the hull; thus obtaining the integral of the ship's slamming pressure on the three-dimensional outer surface of the hull and the slamming pressure distribution on the three-dimensional outer surface of the hull.

[0025] Further, step 1.2 specifically involves: based on the coordinate information of all intersection points obtained from the horizontal section and mesh cutting in step 1.1, using the longitudinal coordinate X of the hull as feature quantity 1, finding the largest longitudinal node coordinate X among all points. max and the smallest vertical node coordinate X min ; Obtain the midpoint coordinates X mid =(X max +X min ) / 2, filter distance X mid The point with the shortest vertical distance is used as the starting point.

[0026] With feature points vertical coordinate Using this as a boundary, all discrete points are divided into groups with vertical coordinates greater than... part1 and less Part 2; sort the discrete points of each separated part; reorder the discrete points of the two parts and the starting point. Merge them into an ordered array to obtain ordered horizontal intersection points. Connect these horizontal intersection points in order according to their numbers to obtain a correct horizontal intersection line. Perform steps 1-2 on all discrete cutting points obtained by cutting the hull mesh on the horizontal plane to obtain the horizontal intersection line of the hull geometry.

[0027] Furthermore, the discrete points of the separated part1 portion are sorted, starting from the first point. As a feature point P0, the distance between the discrete points in the part set and the feature point P0 is calculated, and the point with the smallest distance is selected and numbered 1. After selecting this point, it is removed from the set part1, and this point is selected as the new feature point P0. The point that is closest to the new feature point P0 among the remaining discrete points in the part1 set is found and numbered 2. The newly selected point is then used as the new feature point P0, and the node that was just selected is removed from the set part1. The above operation is repeated, thereby reordering the discrete points in the set part1. The sorting of the discrete points in part2 is also performed in the same way.

[0028] Further, step 2.1 specifically includes:

[0029] The longitudinal angle of the cut surface, calculated from the relative motion of the ship's waves, is, in potential flow theory, the longitudinal angle U at the corresponding wavefront position for a given point P with coordinates X, Y, Z. WaveX and vertical U WaveZ The speed of motion is:

[0030] U WaveX =Aω·e kZ ·cos(β)·cos(kX·cos(β)+kY·cos(β)-ωt)

[0031] U WaveZ =Aω·e kZ ·sin(kX·cos(β)+kY·cos(β)-ωt)

[0032] Where: A is the wave amplitude, ω is the wave frequency, k is the wave number, and β is the wave direction angle;

[0033] The 6-DOF motion of the ship results in a point P, which is fixed to the ship, with the following linear velocity:

[0034] U ShipX =U0+U1+(0,U5,U6)×(r1,r1,r2)

[0035] U ShipZ =U3+(U4,U5,0)×(r1,r1,r2)

[0036] Among them: U ShipX with U ShipZLet P represent the longitudinal and vertical velocities of point P, which is fixed to the hull; U0 represents the ship's speed, which is consistent with the longitudinal direction of the hull; (U1, U2, U3, U4, U5, U6) represent the sway velocities of the ship's six degrees of freedom: pitch, roll, heave, roll, pitch, and yaw, respectively; (r1, r1, r2) represent the radius vector from the ship's center of gravity to point P; by calculating the velocities of points on the wave surface and the velocities of these points fixed to the hull caused by the ship's motion, the relative velocity of the ship to the wave at that location can be obtained.

[0037] U X =U ShipX -U WaveX

[0038] U Z =U ShipZ -U WaveZ

[0039] Based on the longitudinal relative velocity U X and the vertical relative velocity U Z Obtain the longitudinal tilt angle θ of the cutting plane that cuts the blast section.

[0040] 1. Further, step 3.3 specifically involves: based on the interpolated and encrypted curve nodes in step 3.2, in the local coordinate system of the two-dimensional profile, using the magnitude of the horizontal coordinate ξ as the criterion, starting from the bottom of the profile and checking upwards one by one to find the curve nodes contained in the concave part, where the absolute value of the horizontal coordinate ξ of the point is less than the absolute value of the coordinate of the starting point P0 of the concave segment.

[0041] Starting from the concave section starting point P0, draw an inclined straight line with an inclination angle of 80 to 90 degrees. Calculate the slope of the drawn straight line, and then calculate the intersection point P1 of the straight line and the two-dimensional blasting section.

[0042] The straight line segment near the intersection point P1 is connected to the two-dimensional slammed section segment by an arc, thus achieving a smooth transition of the curve slope. By specifying the radius of the transition arc, the center P of the arc is calculated based on the coordinates of the intersection point P1 and the slope of the slammed section at point P1. r Next, find point P2 on the straight line segment that is tangent to the arc; at this point, the straight line segment P0P2 and the arc segment used to replace the concave curve segment have been found.

[0043] The beneficial effects of this invention are as follows:

[0044] This invention provides an efficient method for rapidly calculating the overall slamming load of ships with speed in medium to high sea states. This method includes cutting and optimizing slamming profiles, and mapping a three-dimensional integral mesh of slamming pressure that considers the influence of hull shape. Based on a user-provided hull mesh model, and according to the longitudinal position of the set two-dimensional cutting profile and the trim angle of the cutting profile obtained through the relative motion of the ship waves (or a directly specified method), the two-dimensional profile for calculating the slamming load of the entire ship is obtained using the two-dimensional profile cutting, smoothing, and optimization algorithms of this invention. This allows the influence of ship speed on the slamming load to be considered. The slamming pressure nodes calculated on the two-dimensional slamming profile are projected onto the actual hull surface, thus enabling the integration of the slamming pressure on the actual hull and displaying the three-dimensional distribution of the slamming pressure on the hull surface.

[0045] This invention provides an automatic and efficient method for slamming load calculation of the entire ship, including slamming profile cutting, smoothing, and correction. For solving the slamming load of the entire ship, it provides an automatic three-dimensional integral mesh mapping method to achieve pressure integration based on the actual ship hull surface. Attached Figure Description

[0046] Figure 1 Flowchart of automatic two-dimensional profile generation and pressure mesh mapping for whole ship impact load calculation;

[0047] Figure 2 Schematic diagram of horizontal cutting of the hull mesh;

[0048] Figure 3 Schematic diagram of the horizontal cutting discrete point sorting algorithm;

[0049] Figure 4 Schematic diagram of the horizontal intersection line of the ship's hull;

[0050] Figure 5 Schematic diagram of determining the longitudinal tilt angle of the cross section by the relative motion velocity of the ship's waves;

[0051] Figure 6 A schematic diagram of a two-dimensional cutting line obtained by cutting a horizontal intersection line with a two-dimensional cross section;

[0052] Figure 7 A schematic diagram of the correction to the concave section of a smooth two-dimensional cutting line;

[0053] Figure 8 A schematic diagram of the two-dimensional slamming load calculation profile distribution for the entire ship;

[0054] Figure 9 A schematic diagram of the projection of the pressure node of the two-dimensional impact section onto the original cutting line that fits the hull shell.

[0055] Figure 10Schematic diagram of the three-dimensional pressure integral mesh on the hull surface;

[0056] Figure 11 A schematic diagram of the distribution of impact pressure on the three-dimensional outer surface of the hull. Detailed Implementation

[0057] The present invention will now be further described with reference to the accompanying drawings.

[0058] This invention provides an efficient method for rapidly calculating the overall slamming load of ships at medium to high sea states. This method includes cutting and optimizing slamming profiles, and mapping a three-dimensional integral mesh of slamming pressure that considers the influence of the hull shape. Based on the user-provided hull mesh geometry file, this invention provides a method using horizontal intersections to describe the hull's geometric shape features. This effectively improves the computational efficiency of subsequently cutting the hull to obtain the slamming profile. For the obtained two-dimensional profiles, this invention provides an automatic correction method for curves with concave sections, ensuring that the obtained two-dimensional profiles are fully suitable for slamming pressure calculations. For the slamming pressure calculated on the two-dimensional profiles, this invention provides a method for mapping pressure nodes onto the three-dimensional hull, thereby forming a three-dimensional pressure integral mesh that fits the hull. Simultaneously, the pressure nodes mapped onto the hull directly describe the three-dimensional distribution of slamming pressure on the hull.

[0059] Taking the calculation of the slamming load of a container ship sailing in waves as an example, the calculation is performed by reading the parameters preset by the user, including: the hull mesh file, the longitudinal position of the cut cross section, the ship speed, the ship rolling speed, and the parameters of the incident waves.

[0060] A method for automatic 2D profile generation and pressure mesh mapping for calculating the slamming load of a ship:

[0061] Step 1: Use equally spaced horizontal intersection lines to simplify the description of the three-dimensional hull features.

[0062] Step 1.1: Use equally spaced vertically distributed horizontal surfaces to cut the 3D hull mesh provided by the user, and obtain the coordinates of all cutting points.

[0063] Step 1.2: For the coordinate information of all intersection points obtained from the horizontal section and the mesh cutting obtained in Step 1.1, using the longitudinal coordinate (X) of the hull as feature quantity 1, find the largest longitudinal node coordinate X among all points. max and the smallest vertical node coordinate X min Obtain the midpoint coordinates X. mid =(X max +X min ) / 2, filter distance X mid The point with the shortest vertical distance is used as the starting point.

[0064] With feature points vertical coordinate Using this as a boundary, all discrete points are divided into groups with vertical coordinates greater than... Part 1 and less than Part 2;

[0065] For each separated part (e.g., part 1), the discrete points are sorted, starting with the starting point. As a feature point P0, the distance between discrete points in the `part` set and feature point P0 is calculated. The point with the smallest distance is selected and numbered 1. This selected point is then removed from the `part1` set, and selected as the new feature point P0. Next, the point among the remaining discrete points in the `part1` set that is closest to the new feature point P0 is found and numbered 2. This newly selected point is then used as the new feature point P0, and the previously selected node is removed from the `part1` set. This process is repeated to reorder the discrete points in the `part1` set. For points smaller than... The sorting of discrete points in part 2 is also performed in this manner;

[0066] Discrete points of the two reordered parts and starting point The points are merged into an ordered array, resulting in an ordered arrangement of horizontal intersection points. Connecting these points in order according to their numbers yields a correct horizontal intersection line. Refer to the execution process described in steps 1-2. Figure 3 Schematic diagram of the horizontal cutting discrete point sorting algorithm. Steps 1-2 are performed on all discrete cutting points obtained by cutting the hull mesh with horizontal planes, thereby obtaining horizontal intersection lines that can simplify the description of the geometry of the hull shell.

[0067] Step 2: Extraction of the original two-dimensional slamming profile.

[0068] Step 2.1: Determine the pitch angle of the cut cross section at the longitudinal position specified by the user. The pitch angle can be directly specified by the user or determined by calculating the relative motion speed of the ship waves.

[0069] The longitudinal angle of the cut surface, calculated from the relative motion of the ship's waves, is, in potential flow theory, the longitudinal angle U at the corresponding wavefront position for a given point P with coordinates (X, Y, Z). WaveX and vertical U WaveZ The speed of motion is:

[0070] U WaveX =Aω·e kZ·cos(β)·cos(kX·cos(β)+kY·cos(β)-ωt)

[0071] U WaveZ =Aω·e kZ ·sin(kX·cos(β)+kY·cos(β)-ωt)

[0072] Where: A is the wave amplitude, ω is the wave frequency, k is the wave number, and β is the wave direction angle. The above formula represents the velocity expression of a point on a wave under the Aray wave model within the framework of potential flow theory. The above formula can be adjusted according to different wave models.

[0073] The linear velocity of point P (assuming P is fixed to the ship) caused by the 6-DOF motion of the hull is:

[0074] U ShipX =U0+U1+(0,U5,U6)×(r1,r1,r2)

[0075] U ShipZ =U3+(U4,U5,0)×(r1,r1,r2)

[0076] Among them: U ShipX with U ShipZ Let U0 represent the longitudinal and vertical velocities of point P, which is fixed to the hull; U0 represent the ship's speed (consistent with the longitudinal direction); (U1, U2, U3, U4, U5, U6) represent the roll velocities of the ship's six degrees of freedom (pitch, sway, heave, roll, pitch, and yaw); (r1, r2) represent the radius vector from the ship's center of gravity to point P. By calculating the velocities of points on the wave surface and the velocities caused by the ship's motion when fixed to the hull, the relative velocity of the ship at that location relative to the wave can be obtained.

[0077] U X =U ShipX -U WaveX

[0078] U Z =U ShipZ -U WaveZ

[0079] Therefore, based on the relative velocity U in the longitudinal direction X and the vertical relative velocity U Z Obtain the longitudinal inclination angle θ of the cutting plane that cuts the slamming profile. Refer to the schematic diagram for the process in step 2.1 of determining the profile inclination angle based on the relative velocity direction of the ship's waves at a given longitudinal position. Figure 5 .

[0080] Step 2.2: Based on the inclination information of the cross section obtained in Step 2-1 and the specified longitudinal position information, intersect the set cutting cross section with the horizontal intersection line in Step 1 to obtain discrete points describing the original two-dimensional slap section.

[0081] Step 3: Smooth and optimize the profile.

[0082] Step 3.1: For the original banging profile discrete points extracted in Step 2, the original nodes are converted into a series of nodes distributed along the profile with equal arc lengths using the equal arc length method;

[0083] Step 3.2: Perform cumulative chord length cubic spline interpolation and refinement on the equal arc length nodes obtained in Step 3.1 to obtain the coordinates and slope information of the curve;

[0084] Step 3.3: For the curve nodes that were interpolated and encrypted in Step 3.2, in the local coordinate system of the two-dimensional section, the horizontal coordinate ξ is used as the criterion. Starting from the bottom of the section, the curve nodes contained in the concave part are checked one by one upwards to find the curve nodes (the absolute value of the horizontal coordinate ξ of the point is less than the absolute value of the coordinate of the starting point P0 of the concave segment).

[0085] Starting from the concave section starting point P0, draw an inclined straight line (the inclination angle ranges from 80 to 90 degrees, which can be specified by the user), calculate the slope of the drawn straight line, and then calculate the intersection point P1 of the straight line and the two-dimensional blasting section.

[0086] The straight line segment near the intersection point P1 is connected to the two-dimensional slammed section segment by an arc, thus achieving a smooth transition of the curve slope. By specifying the radius of the transition arc, the center P of the arc is calculated based on the coordinates of the intersection point P1 and the slope of the slammed section at point P1. r Next, find the point P2 on the straight line segment that is tangent to the circular arc. At this point, the straight line segment P0P2 and the circular arc segment used to replace the concave curve segment have been found. The schematic diagram for correcting the concave curve segment in the two-dimensional section in step 3.3 is shown below. Figure 7 .

[0087] Step 3 is performed on all the discrete points of the two-dimensional original curves cut by the cross section to obtain two-dimensional slamming profiles that can be directly used to calculate slamming pressure, which are distributed throughout the entire length of the hull.

[0088] Step 4: Projection of pressure nodes on the blast line onto the three-dimensional hull shell.

[0089] Step 4.1: For the two-dimensional slammed profile in Step 3, select the projection center feature point P0 based on the coordinates of the bottom and top nodes of the slammed profile, and use it as the starting point for the straight line projection.

[0090] Step 4.2: Connect the projection center point P0 and the pressure nodes on the two-dimensional impact section line with a straight line, calculate the intersection of the projection line and the original cutting section line in step 2, and thus obtain the pressure projection points distributed on the three-dimensional shell of the ship.

[0091] Step 4.3: Based on the coordinates of the pressure projection points distributed on the three-dimensional outer shell of the hull obtained in Step 4.2, the projection points corresponding to adjacent cutting lines are interconnected to obtain the pressure integration grid distributed on the three-dimensional outer shell of the hull. This enables the integration of the slamming pressure of the entire ship on the three-dimensional outer surface of the hull, and also allows the acquisition of the slamming pressure distribution on the three-dimensional outer surface of the hull.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for automatic two-dimensional profile generation and pressure mesh mapping for calculating the slamming load of a ship, characterized in that: The specific steps are as follows: Step 1: Use equally spaced horizontal intersection lines to simplify the description of the three-dimensional hull features; Step 1.1: Based on the hull outer surface mesh file provided by the user, cut the hull outer surface mesh with horizontal planes distributed at equal intervals along the height to obtain all the cutting points; Step 1.2: Based on the coordinate information of the cutting points obtained in Step 1.1, the cutting points are numbered and sorted using the feature point spacing sorting algorithm to obtain an ordered arrangement of points that can form a line from the stern to the bow or from the bow to the stern, thus obtaining a discrete point array describing the horizontal intersection information. Step 2: Extraction of the original 2D slamming profile contour; Step 2.1: At the longitudinal position specified by the user, based on the direction of the relative motion velocity of the ship wave at the given position point, or directly provided by the user, obtain the longitudinal angle of the cross section used to cut the horizontal intersection line in Step 1. Step 2.2: Based on the inclination information of the cross section obtained in Step 2.1 and the specified longitudinal position information, intersect the set cutting cross section with the above-mentioned horizontal intersection line to obtain a discrete point array describing the original two-dimensional slap section. Step 3: Smoothing and optimizing the profile contour; Step 3.1: Based on the original banging profile discrete points extracted in Step 2, the original nodes are converted into a series of nodes distributed along the profile with equal arc lengths using the equal arc length method; Step 3.2: Perform cumulative chord length cubic spline interpolation and refinement on the equal arc length nodes obtained in Step 3.1 to obtain the coordinates and slope information of the curve; Step 3.3: Filter the interpolated and encrypted curves in Step 3.2, identify the concave segments, and replace the concave segments with inclined straight lines and end arcs to make the two-dimensional profile monotonically increasing, thus obtaining a two-dimensional calculation profile that meets the requirements of impact pressure calculation. Step 4: Projection of pressure nodes on the impact section line onto the three-dimensional hull shell; Step 4.1: For the two-dimensional slammed section in Step 3, select the projection center feature point based on the coordinates of the bottom and top nodes of the slammed section; Step 4.2: Based on the pressure nodes on the two-dimensional impact section line connecting the projection center point and the pressure nodes, calculate the intersection of the projection line and the original cutting section line in Step 2 to obtain the pressure projection points distributed on the three-dimensional outer shell of the ship. Step 4.3: Based on the coordinates of the pressure projection points distributed on the three-dimensional outer shell of the hull obtained in Step 4.2, the projection points corresponding to adjacent cutting lines are interconnected to obtain the pressure integral grid distributed on the three-dimensional outer shell of the hull; the integral of the ship slamming pressure on the three-dimensional outer surface of the hull and the slamming pressure distribution on the three-dimensional outer surface of the hull are obtained.

2. The method for automatic two-dimensional profile generation and pressure mesh mapping for calculating the slamming load of a ship according to claim 1, characterized in that: Step 1.2 specifically involves: based on the coordinate information of all intersection points obtained from the horizontal section and mesh cutting in step 1.1, using the longitudinal coordinate X of the hull as feature quantity 1, finding the largest longitudinal node coordinate X among all points. max and the smallest vertical node coordinate X min ; Obtain the midpoint coordinates X mid =(X max +X min ) / 2, filter distance X mid The point with the shortest vertical distance is used as the starting point. ; With feature points vertical coordinate Using this as a boundary, all discrete points are divided into groups with vertical coordinates greater than... part1 and less Part 2; sort the discrete points of each separated part; reorder the discrete points of the two parts and the starting point. Merge them into an ordered array to obtain ordered horizontal intersection points. Connect these horizontal intersection points in order according to their numbers to obtain a correct horizontal intersection line. Perform steps 1-2 on all discrete cutting points obtained by cutting the hull mesh on the horizontal plane to obtain the horizontal intersection line of the hull geometry.

3. The method for automatic two-dimensional profile generation and pressure mesh mapping for calculating the slamming load of a ship according to claim 2, characterized in that: The discrete points of the separated part 1 are sorted, starting from the first point. As feature points By calculating the discrete points and feature points in the part set The distance is calculated, and the point with the smallest distance is selected and numbered 1. After selecting this point, it is removed from set part1, and then selected as a new feature point. Find new feature points among the remaining discrete points in the part1 set. The nearest point is numbered 2, and the newly selected point is used as the new feature point. Then, the nodes that were just selected are removed from set part1, and the above operation is repeated to reorder the discrete points in set part1; the sorting of discrete points in part2 is also performed in the same way.

4. The method for automatic two-dimensional profile generation and pressure mesh mapping for calculating the slamming load of a ship according to claim 1, characterized in that: Step 2.1 specifically involves: The longitudinal angle of the cut surface, calculated from the relative motion of the ship's waves, is, in potential flow theory, the longitudinal angle of the wavefront at a given point P with coordinates X, Y, Z. and vertical The speed of motion is: in: The amplitude of the wave. Where k is the wave frequency and k is the wave number. For the wave angle; The linear velocity of point P, which is fixed to the ship, is caused by the ship's 6-DOF motion. in: and This represents the longitudinal and vertical velocities of point P, which is fixed to the hull. This indicates the ship's speed and is consistent with the ship's longitudinal direction. These represent the sway speeds of the ship's six degrees of freedom: pitch, sway, heave, roll, pitch, and yaw. The radius vector from the ship's center of gravity to point P; by calculating the velocity of a point on the wave surface and the velocity of that point fixed to the hull caused by the ship's motion, the relative velocity of the ship and the wave at that location can be obtained: Based on the relative velocity in the longitudinal direction and vertical relative velocity Obtain the longitudinal angle of the cutting plane of the blast section. .

5. The method for automatic two-dimensional profile generation and pressure mesh mapping for calculating the slamming load of a ship according to claim 1, characterized in that: Step 3.3 specifically involves: based on the interpolated and encrypted curve nodes from step 3.2, within the local coordinate system of the two-dimensional profile, using the horizontal coordinates... The size is used as the basis for judgment. Starting from the bottom of the section line, check upwards one by one to find the curve nodes contained in the concave part, and the horizontal coordinates of the points. The absolute value is less than the starting point of the concave segment. The absolute value of the coordinates; From the starting point of the concave segment Starting from this point, draw an inclined straight line with an angle ranging from 80 to 90 degrees. Calculate the slope of the drawn line, and then calculate the intersection point of the line with the two-dimensional slammed section. ; Intersection The nearby straight line segments are connected to the two-dimensional slammed section segments by circular arcs, thus achieving a smooth transition of the curve slope; by specifying the radius of the transition arc, based on the intersection point... coordinates and The center of the arc is calculated by the slope of the section line at the point of impact. Then find the point on the straight line segment that is tangent to the arc. ; Thus, the straight line segment used to replace the concave section of the curve has been found. and arc segments .

Images