On-board forming limit diagram drawing method, device and equipment, medium and product

Abstract

The invention discloses an on-board forming limit diagram drawing method, device and equipment, a medium and a product, and relates to the technical field of graphic rendering. According to the method, primary and secondary strain values of grid vertexes on the outer surface of a three-dimensional model of a target plate are used as mapping coordinates to be arranged on the corresponding vertexes, and then the mapping coordinates of the grid vertexes on corresponding grid patches are transmitted to corresponding pixel shaders for a vertex shader. The method comprises the following steps: transmitting a map coordinate to a pixel shader, rasterizing the transmitted map coordinate to obtain a pixel map coordinate, extracting pixel primary and secondary strain values from the pixel map coordinate in the pixel shader, determining a pixel color for drawing a formed limit diagram by combining material parameters, and finally rendering the pixel color to the outer surface of a model. Therefore, the color positioning accuracy and the FLD boundary smoothness can be greatly improved, and the sensing accuracy of the plate fracture risk can be improved.

Description

Technical Field

[0001] The present invention belongs to the field of graphics rendering technology, and in particular relates to a method, device, equipment, medium and product for drawing a forming limit diagram on a plate. Background Art

[0002] The Forming Limit Diagram (FLD) is a graphical representation used to describe the rupture limit of a material under plane stress. It has a wide range of applications in fields such as metal forming engineering, aerospace, and automotive manufacturing. By studying the FLD, engineers can predict the risk of material rupture during the forming process, thereby optimizing process parameters, improving product quality, and reducing production costs. The FLD mainly consists of two parts: the limit strain curve and the rupture point. The limit strain curve represents the maximum plastic strain capacity of the material under plane stress, while the rupture point indicates the stress state at which the material begins to rupture.

[0003] At present, the existing technical solution for drawing the forming limit diagram on the outer surface of the sheet metal model is: using mesh patches such as triangular patches and / or quadrilateral patches located on the outer surface of the sheet metal model as the minimum coloring unit, and based on the principal strain values and secondary strain values of each vertex located on the patch, combined with the Keeler formula (which is an existing method for predicting the forming limit diagram of a material) and material parameters, calculate the regional color value of the corresponding patch (for example, red is used to represent the color of the rupture area; yellow is used to represent the color of the rupture risk area; green is used to represent the color of the safe area; light blue is used to represent the color of the wrinkling risk area; pink is used to represent the color of the wrinkling area; purple is used to represent the color of the severe wrinkling area; gray is used to represent the color of the effective strain insufficient area; etc.), and the final forming limit diagram of the sheet metal is as follows. Figure 1 shown.

[0004] But just as Figure 1 As shown, since the minimum shading unit is a patch rather than a pixel, the above-mentioned existing technical solutions will be difficult to meet the requirements for drawing more accurate color positioning and smoother FLD boundary lines. Summary of the Invention

[0005] The purpose of the present invention is to provide a method, device, computer equipment, computer-readable storage medium and computer program product for drawing a forming limit diagram on a plate, so as to solve the problem that the existing forming limit diagram drawing scheme on the plate is difficult to meet the requirements of drawing more accurate color positioning and smoother FLD dividing lines.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a method for drawing a forming limit diagram on a plate is provided, comprising:

[0008] Obtaining the principal strain value and the secondary strain value of each mesh vertex located on the outer surface of the model of the target sheet metal three-dimensional model;

[0009] For each mesh vertex, the corresponding principal strain value and secondary strain value are set as mapping coordinates on the corresponding vertex;

[0010] For each mesh patch located on the outer surface of the model, setting a corresponding vertex shader and pixel shader;

[0011] For the vertex shader, passing the texture coordinates of the mesh vertices located on the corresponding mesh face to the corresponding pixel shader;

[0012] rasterizing the texture coordinates passed to the pixel shader, so that the pixel shader obtains pixel texture coordinates calculated by an interpolation algorithm in a rasterization process;

[0013] In the pixel shader, the pixel principal strain value and the pixel secondary strain value are extracted from the pixel map coordinates, and the pixel color used for drawing the forming limit diagram is determined in combination with the material parameters of the target sheet metal three-dimensional model;

[0014] The pixel colors are rendered onto the outer surface of the model to obtain a forming limit diagram of the plate.

[0015] Based on the above invention content, a new scheme for drawing the forming limit diagram on the plate using pixels as the minimum shading unit is provided, that is, the major and minor strain values of each mesh vertex located on the outer surface of the model of the target plate three-dimensional model are first set as mapping coordinates to the corresponding vertices, and then for the vertex shader, the mapping coordinates of the mesh vertex located on the corresponding mesh facet are passed to the corresponding pixel shader, and the passed mapping coordinates are rasterized to obtain pixel mapping coordinates, and then in the pixel shader, the major and minor strain values of the pixel are extracted from the pixel mapping coordinates, and combined with the material parameters, the pixel color used to draw the forming limit diagram is determined, and finally the pixel color is rendered on the outer surface of the model, thereby greatly improving the color positioning accuracy and the smoothness of the FLD boundary line, so that any color changes caused by subtle changes in the major and minor strain values can be reflected in the final display result, which is beneficial to improving the perception accuracy of the risk of plate rupture and facilitating practical application and promotion.

[0016] In one possible design, a graphics rendering system based on Hoops, OpenGL, DirectX, or Vulkan is used to implement the on-board forming limit diagram rendering method.

[0017] In one possible design, when the Hoops-based graphics rendering system is used to implement the plate forming limit diagram rendering method, for each mesh vertex, the corresponding principal strain value and secondary strain value are set together as mapping coordinates to the corresponding vertex, including:

[0018] For each mesh vertex, the HC_Set_Parameter setting function is used to set the corresponding primary strain value and secondary strain value as mapping coordinates to the corresponding vertex.

[0019] In one possible design, when the Hoops-based graphics rendering system is used to implement the forming limit diagram drawing method on a plate, a corresponding vertex shader and pixel shader are set for each mesh face located on the outer surface of the model, including:

[0020] For each mesh patch located on the outer surface of the model, the HC_Set_Shader setting function is used to set the corresponding vertex shader and pixel shader.

[0021] In a possible design, the material parameters include a plastic strain ratio value, a principal strain value when the secondary strain is zero, a strain hardening exponent value, a plate thickness, a safety region value, and / or an allowable thickening interval value.

[0022] In one possible design, the pixel principal strain value and the pixel secondary strain value are extracted from the pixel map coordinates, and the pixel color for drawing the forming limit diagram is determined in combination with the material parameters of the target sheet metal three-dimensional model, including the following steps S61 to S68 performed in sequence:

[0023] S61. Extracting the pixel primary strain value y and the pixel secondary strain value x from the pixel map coordinates;

[0024] S62. Determine whether the pixel principal strain value y is less than or equal to the first curve function GreenLine(r,x) in the Keeler formula. If so, determine the color of the pixel to be assigned as a first color indicating a wrinkling risk area, wherein the first curve function GreenLine(r,x) is expressed as follows:

[0025]

[0026] Wherein, r represents the plastic strain ratio value in the material parameters of the target sheet three-dimensional model;

[0027] S63. Determine whether the pixel principal strain value y is less than or equal to the second curve function BlueLine(x) in the Keeler formula. If so, determine the color of the pixel to be assigned as a second color for indicating being in a wrinkled area, wherein the second curve function BlueLine(x) is expressed as follows: BlueLine(x)=-x;

[0028] S64. Determine whether the pixel principal strain value y is less than or equal to the third curve function PinkLine(r,x) in the Keeler formula. If so, determine that the color of the pixel to be assigned is the third color used to indicate a severely wrinkled area, wherein the third curve function PinkLine(r,x) is expressed as follows:

[0029] S65. Determine whether the pixel principal strain value y is greater than or equal to the fourth curve function YellowLine(FLD0, x, safe region ), if so, the color of the pixel to be assigned is determined to be the fourth color for indicating a rupture risk area, wherein the fourth curve function YellowLine(FLD0,x,safe region ) is represented as follows:

[0030]

[0031] Where FLD0 represents the principal strain value in the material parameters when the secondary strain is zero, safety region represents a safe zone value within the material parameter;

[0032] S66. Determine whether the pixel principal strain value y is greater than or equal to the fifth curve function RedLine(FLD0, x) in the Keeler formula. If so, determine that the color of the pixel to be assigned is the fifth color used to indicate that it is in a rupture area, wherein the fifth curve function RedLine(FLD0, x) is expressed as follows:

[0033]

[0034] S67. Determine whether the pixel principal strain value y is less than or equal to the sixth curve function DiagonalGreyLine (allowable thickening ,x) and whether the pixel secondary strain value x is greater than or equal to the seventh curve function VerticalGreyLine(allowable thickening), if so, then determine that the color of the pixel to be assigned is the sixth color for indicating the effective strain deficiency area, wherein the sixth curve function DiagonalGreyLine (allowable thickening ,x) and the seventh curve function VerticalGreyLine(allowable thickening ) are respectively represented as follows:

[0035]

[0036] Where allowable thickening Indicates the allowable thickening range value in the material parameters;

[0037] S68. Determine the pixel color used to draw the forming limit diagram as the pixel color to be assigned;

[0038] The above steps S62 to S67 are allowed to be retained in any one of them or any combination thereof.

[0039] In a second aspect, a forming limit diagram drawing device for a plate is provided, comprising a strain data acquisition module, a mapping coordinate setting module, a shader setting module, a mapping coordinate transfer module, a rasterization processing module, a pixel color determination module, and a pixel color rendering module;

[0040] The strain data acquisition module is used to acquire the primary strain value and the secondary strain value of each grid vertex located on the outer surface of the model of the target plate three-dimensional model;

[0041] The mapping coordinate setting module is communicatively connected to the strain data acquisition module, and is used to set the corresponding primary strain value and secondary strain value as mapping coordinates to the corresponding vertex for each mesh vertex;

[0042] The shader setting module is used to set corresponding vertex shaders and pixel shaders for each mesh surface located on the outer surface of the model;

[0043] The texture coordinate transfer module is communicatively connected to the texture coordinate setting module and the shader setting module, and is used to transfer the texture coordinates of the mesh vertices located on the corresponding mesh face to the corresponding pixel shader for the vertex shader;

[0044] The rasterization processing module is communicatively connected to the texture coordinate transfer module and is used to rasterize the texture coordinates transferred to the pixel shader so that the pixel shader obtains pixel texture coordinates calculated by an interpolation algorithm in a rasterization process;

[0045] The pixel color determination module is communicatively connected to the rasterization processing module and is configured to extract, in the pixel shader, the pixel principal strain value and the pixel secondary strain value from the pixel map coordinates, and determine the pixel color for drawing the forming limit diagram in combination with the material parameters of the target sheet metal three-dimensional model;

[0046] The pixel color rendering module is communicatively connected to the pixel color determination module and is used to render the pixel color onto the outer surface of the model to obtain a forming limit diagram on the plate.

[0047] In a third aspect, the present invention provides a computer device comprising a memory, a processor and a transceiver which are communicatively connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the method for drawing a forming limit diagram on a plate as described in the first aspect or any possible design of the first aspect.

[0048] In a fourth aspect, the present invention provides a computer-readable storage medium having instructions stored thereon, which, when executed on a computer, executes the method for drawing a forming limit diagram on a plate as described in the first aspect or any possible design of the first aspect.

[0049] In a fifth aspect, the present invention provides a computer program product comprising a computer program or instructions, which, when executed by a computer, implements the method for drawing a forming limit diagram on a plate as described in the first aspect or any possible design of the first aspect.

[0050] Beneficial effects of the above scheme:

[0051] (1) The present invention creatively provides a new scheme for drawing the forming limit diagram on the plate using pixels as the minimum shading unit, that is, first, the primary and secondary strain values of each grid vertex on the outer surface of the model of the target plate three-dimensional model are set as mapping coordinates to the corresponding vertex, and then, for the vertex shader, the mapping coordinates of the grid vertex on the corresponding grid face are passed to the corresponding pixel shader, and the passed mapping coordinates are rasterized to obtain pixel mapping coordinates, and then in the pixel shader, the pixel primary and secondary strain values are extracted from the pixel mapping coordinates, and combined with the material parameters, the pixel color used to draw the forming limit diagram is determined, and finally the pixel color is rendered on the outer surface of the model, thereby greatly improving the color positioning accuracy and the smoothness of the FLD boundary line, so that any color change caused by slight changes in the primary and secondary strain values can be reflected in the final display result, which is conducive to improving the perception accuracy of the plate fracture risk and facilitating practical application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0053] Figure 1 An example diagram of a forming limit diagram on a plate obtained using an existing drawing solution provided in the prior art.

[0054] Figure 2 A schematic flow chart of a method for drawing a forming limit diagram on a plate provided in an embodiment of the present application.

[0055] Figure 3 An example diagram of rasterizing triangular facets provided in an embodiment of the present application.

[0056] Figure 4 This is an example diagram of the positional relationship of multiple forming limit curves in a plane coordinate system provided in an embodiment of the present application.

[0057] Figure 5 This is an example diagram of the forming limit diagram on a plate obtained using the solution of the present application provided in an embodiment of the present application.

[0058] Figure 6 This is a schematic structural diagram of the device for drawing a forming limit diagram on a plate provided in an embodiment of the present application.

[0059] Figure 7 A schematic diagram of the structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be briefly introduced below in conjunction with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structures of the drawings is only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these embodiments without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0061] It should be understood that although the terms first, second, etc. may be used herein to describe various objects, these objects should not be limited by these terms. These terms are merely used to distinguish one object from another. For example, a first object can be referred to as a second object, and similarly, a second object can be referred to as a first object without departing from the scope of the exemplary embodiments of the present invention.

[0062] It should be understood that the term "and / or" that may appear in this document is merely a description of the association relationship between associated objects, indicating that there may be three relationships. For example, A and / or B can indicate three situations: A exists alone, B exists alone, or A and B exist at the same time. For another example, A, B and / or C can indicate the existence of any one of A, B and C or any combination of them. The term " / and" that may appear in this document describes another type of association object relationship, indicating that there may be two relationships. For example, A / and B can indicate two situations: A exists alone or A and B exist at the same time. In addition, the character " / " that may appear in this document generally indicates that the previous and next associated objects are in an "or" relationship.

[0063] Example

[0064] like Figures 2 to 5 As shown, the method for drawing the forming limit diagram on the plate provided in the first aspect of this embodiment can be, but is not limited to, executed by a computer device with certain computing resources, such as a graphics processing server, a cloud server, a personal computer (Personal Computer, PC, refers to a multi-purpose computer with a size, price and performance suitable for personal use; desktops, laptops, small laptops and tablets and ultrabooks are all personal computers), a smart phone, a personal digital assistant (Personal Digital Assistant, PDA) or a wearable device. Figure 2 As shown, the method for drawing the forming limit diagram on the plate may include, but is not limited to, the following steps S1 to S7.

[0065] S1. Obtaining the principal strain value and the secondary strain value of each mesh vertex located on the outer surface of the model of the target sheet material three-dimensional model.

[0066] In step S1, the principal strain values and secondary strain values of each mesh vertex are the data basis for drawing the forming limit diagram on the plate, and can be obtained based on existing conventional forming limit diagram drawing solutions for plates. For example, when using a graphics rendering system based on Hoops (i.e., HOOPS Visualize, a high-performance 3D graphics rendering engine based on retained mode, designed for real-time visualization of complex 3D scenes) to implement this embodiment, the following C++ code can be used to obtain and implement it, but is not limited to:

[0067] #include<HUtility.h>

[0068] #include <vector>

[0069] int point_count; / / Number of vertices

[0070] std::vector major_strain(point_count); / / Vertex major strain value

[0071] std::vector minor_strain(point_count); / / Vertex strain value

[0072] S2. For each mesh vertex, the corresponding principal strain value and secondary strain value are set as mapping coordinates on the corresponding vertex.

[0073] In step S2, the mapping coordinates refer to the two-dimensional coordinates of each pixel on the positioning map on the surface of the three-dimensional model, and are usually represented by two coordinate axes, such as the U axis and the V axis, similar to the X axis and the Y axis of a two-dimensional plane. For example, when using a Hoops-based graphics rendering system to implement this embodiment, for each mesh vertex, the corresponding primary strain value and secondary strain value can be set as the mapping coordinates to the corresponding vertex using the HC_Set_Parameter setting function or other mapping coordinate setting function. This setting can be implemented using, but is not limited to, the following C++ code:

[0074]

[0075] S3. For each mesh patch located on the outer surface of the model, set a corresponding vertex shader and pixel shader.

[0076] In the step S3, the mesh facets may be, but are not limited to, triangular facets or quadrilateral facets, etc. Considering the concept of the image rendering pipeline (i.e., Rendering Pipeline, which is a processing flow in computer graphics for generating two-dimensional images to represent three-dimensional scenes, which describes a series of consecutive steps, starting from the original three-dimensional model data, through a series of calculations and processing, and finally converted into pixels that can be seen on the screen) in this embodiment, each mesh vertex needs to be converted into mapping coordinates in the user visualization window through the vertex shader so that the rendering pipeline can rasterize (i.e., Rasterization, which is the process of converting vector geometric data such as triangles described by vertices into screen pixel arrays in computer graphics) the converted mesh (for example, dividing a line into individual pixels displayed on the screen; taking triangular facet rasterization as an example, as Figure 3 As shown in the figure, each pixel point then passes through a pixel shader (or fragment shader) to calculate the pixel color. Therefore, it is necessary to first set the corresponding vertex shader and pixel shader for each mesh face. For example, when using a Hoops-based graphics rendering system to implement this embodiment, for each mesh face located on the outer surface of the model, the HC_Set_Shader setting function or other shader setting function can be used to set the corresponding vertex shader and pixel shader. Taking a triangle face as an example, the following C++ code can be used for setting and implementation, but is not limited to:

[0077] #include<HUtility.h>

[0078] char const*const vertex_shader_string; / / Vertex shader code string

[0079] char const*const pixel_shader_string; / / Pixel shader code string

[0080] HC_KEY vertex_shader_key = HC_Define_Shader("vertex_shader", "vertex", vertex_shader_string); / / define the vertex shader handle

[0081] HC_KEY pixel_shader_key = HC_Define_Shader("pixel_shader", "pixel", pixel_shader_string); / / Define pixel shader handle

[0082] HC_Set_Shader("triangles", vertex_shader_key, pixel_shader_key); / / Define triangle shader

[0083] S4. For the vertex shader, pass the texture coordinates of the mesh vertices located on the corresponding mesh face to the corresponding pixel shader.

[0084] In step S4, for example, when a Hoops-based graphics rendering system is used to implement this embodiment, the vertex shader may be implemented by, but not limited to, using the following C++ code:

[0085]

[0086] S5. Rasterize the texture coordinates passed to the pixel shader, so that the pixel shader obtains pixel texture coordinates calculated by an interpolation algorithm in the rasterization process.

[0087] In step S5, the texture coordinate rasterization is performed by rasterizing the primary and secondary strain values of the mesh vertices, so that the pixel shader obtains interpolated primary and secondary strain values (i.e., the pixel texture coordinates). The specific rasterization and interpolation calculation processes can be derived from conventional graphics rasterization techniques and are not further described here. Furthermore, for example, when implementing this embodiment using a Hoops-based graphics rendering system, the entire step S5 can be implemented within Hoops.

[0088] S6. In the pixel shader, the pixel principal strain value and the pixel secondary strain value are extracted from the pixel map coordinates, and the pixel color used to draw the forming limit diagram is determined in combination with the material parameters of the target sheet metal three-dimensional model.

[0089] In step S6, the material parameters may be obtained by user input, including but not limited to the plastic strain ratio, the principal strain value when the secondary strain is zero, the strain hardening exponent value, the plate thickness, the safety zone value and / or the allowable thickening interval value. In the process of drawing the forming limit diagram, multiple forming limit curves (FLC) are applied to achieve the purpose of differentiated coloring, such as Figure 4 In order to minimize the demand for computing resources by the pixel shader, preferably, the pixel principal strain value and the pixel secondary strain value are extracted from the pixel map coordinates, and the pixel color used for drawing the forming limit diagram is determined in combination with the material parameters of the target sheet metal three-dimensional model, including the following steps S61 to S68 performed in sequence.

[0090] S61. Extract the pixel primary strain value y and the pixel secondary strain value x from the pixel map coordinates.

[0091] S62. Determine whether the pixel principal strain value y is less than or equal to the first curve function GreenLine(r,x) in the Keeler formula. If so, determine the color of the pixel to be assigned as a first color indicating a wrinkling risk area, wherein the first curve function GreenLine(r,x) is expressed as follows:

[0092]

[0093] Wherein, r represents the plastic strain ratio value in the material parameters of the target sheet material three-dimensional model.

[0094] In step S62, the forming limit curve corresponding to the first curve function GreenLine(r,x) is Figure 4 In addition, the first color is, for example but not limited to, light blue; and the color of the pixel to be assigned can be initialized to green so as to be safe by default.

[0095] S63. Determine whether the pixel principal strain value y is less than or equal to the second curve function BlueLine(x) in the Keeler formula. If so, determine that the color of the pixel to be assigned is the second color used to indicate that it is in a wrinkled area, wherein the second curve function BlueLine(x) is expressed as follows: BlueLine(x) = -x.

[0096] In step S63, the forming limit curve corresponding to the second curve function BlueLine(x) is Figure 4 In addition, the second color is, for example but not limited to, pink.

[0097] S64. Determine whether the pixel principal strain value y is less than or equal to the third curve function PinkLine(r,x) in the Keeler formula. If so, determine that the color of the pixel to be assigned is the third color used to indicate a severely wrinkled area, wherein the third curve function PinkLine(r,x) is expressed as follows:

[0098] In step S64, the forming limit curve corresponding to the third curve function PinkLine(r,x) is Figure 4 In addition, the third color is, for example but not limited to, purple.

[0099] S65. Determine whether the pixel principal strain value y is greater than or equal to the fourth curve function YellowLine(FLD0, x, safe region ), if so, the color of the pixel to be assigned is determined to be the fourth color for indicating a rupture risk area, wherein the fourth curve function YellowLine(FLD0,x,safe region ) is represented as follows:

[0100]

[0101] Where FLD0 represents the principal strain value in the material parameters when the secondary strain is zero, safety region Indicates the safe zone value within the material parameter.

[0102] In the step S65, the fourth curve function YellowLine(FLD0,x,safe region ) The corresponding forming limit curve is Figure 4 If the material parameters do not include FLD0 but include the strain hardening exponent value and plate thickness, FLD0 can be calculated according to the following formula:

[0103]

[0104] Wherein, n represents the strain hardening index value, t represents the plate thickness. In addition, the fourth color is, for example but not limited to, yellow, and the safety zone value is safe region It can be a user-defined constant or a constant from Figure 4 The percentage result of the distance from the FLC5 line to the X axis.

[0105] S66. Determine whether the pixel principal strain value y is greater than or equal to the fifth curve function RedLine(FLD0, x) in the Keeler formula. If so, determine that the color of the pixel to be assigned is the fifth color used to indicate that it is in a rupture area, wherein the fifth curve function RedLine(FLD0, x) is expressed as follows:

[0106]

[0107] In step S66, the forming limit curve corresponding to the fifth curve function RedLine(FLD0,x) is Figure 4 In addition, the fifth color is, for example but not limited to, red.

[0108] S67. Determine whether the pixel principal strain value y is less than or equal to the sixth curve function DiagonalGreyLine (allowable thickening ,x) and whether the pixel secondary strain value x is greater than or equal to the seventh curve function VerticalGreyLine(allowable thickening ), if so, then determine that the color of the pixel to be assigned is the sixth color for indicating the effective strain deficiency area, wherein the sixth curve function DiagonalGreyLine (allowable thickening ,x) and the seventh curve function VerticalGreyLine(allowable thickening ) are respectively represented as follows:

[0109]

[0110] Where allowable thickening Indicates the allowable thickening range value in the material parameters.

[0111] In the step S67, the sixth curve function DiagonalGreyLine (allowable thickening ,x) corresponds to the forming limit curve is Figure 4 FLC6 in; and the seventh curve function VerticalGreyLine(allowable thickening ) The corresponding forming limit curve is Figure 4 In addition, the sixth color is, for example but not limited to, gray, and the allowable thickening interval value is allowable thickening It can also be a user-defined constant.

[0112] S68. Determine the pixel color used to draw the forming limit diagram as the pixel color to be assigned.

[0113] Before step S68, other curve functions (such as Figure 4 The orange curve FLC8 in the figure is used for more detailed coloring. The above steps S62 to S67 are independent of each other, so any one of them or any combination thereof can be retained, that is, only steps S62, S63, S64, S65, S66 or S67 can be used (for example, extracting the pixel principal strain value and the pixel secondary strain value from the pixel map coordinates, and combining the material parameters of the target sheet metal three-dimensional model to determine the pixel color for drawing the forming limit diagram, including steps S61, S64 and S68 performed in sequence), or only any combination of steps S62, S63, S64, S65, S66 and S67 can be used (for example, extracting the pixel principal strain value and the pixel secondary strain value from the pixel map coordinates, and combining the material parameters of the target sheet metal three-dimensional model to determine the pixel color for drawing the forming limit diagram, including steps S61, S63, S64, S67 and S68 performed in sequence).

[0114] In step S6, for example, when a Hoops-based graphics rendering system is used to implement this embodiment, steps S61 to S68 may be implemented by, but not limited to, the following C++ code:

[0115]

[0116] S7. Render the pixel color onto the outer surface of the model to obtain the forming limit diagram of the plate. In step S7, the color rendering can be completed by using existing rendering technology to obtain the following: Figure 5 The forming limit diagram of the plate shown in the figure is compared with Figure 1 In comparison, this embodiment significantly improves color positioning accuracy and FLD boundary smoothness, ensuring that any color changes caused by subtle variations in primary and secondary strain values are reflected in the final display, thereby improving the accuracy of plate fracture risk perception. Furthermore, this embodiment can also be implemented using, but not limited to, graphics rendering systems based on OpenGL, DirectX, or Vulkan. The specific steps of this embodiment can also be implemented using, but not limited to, programming languages such as C, Java, Python, Matlab, or JavaScript.

[0117] Therefore, based on the method for drawing the forming limit diagram on the plate described in the aforementioned steps S1 to S7, a new scheme for drawing the forming limit diagram on the plate using pixels as the minimum shading unit is provided, that is, the major and minor strain values of each mesh vertex located on the outer surface of the model of the target plate three-dimensional model are first set as mapping coordinates to the corresponding vertices, and then, for the vertex shader, the mapping coordinates of the mesh vertex located on the corresponding mesh face are passed to the corresponding pixel shader, and the passed mapping coordinates are rasterized to obtain pixel mapping coordinates. Then, in the pixel shader, the major and minor strain values of the pixel are extracted from the pixel mapping coordinates, and combined with the material parameters, the pixel color used to draw the forming limit diagram is determined, and finally the pixel color is rendered on the outer surface of the model. This can greatly improve the color positioning accuracy and the smoothness of the FLD boundary line, so that any color changes caused by subtle changes in the major and minor strain values can be reflected in the final display result, which is beneficial to improving the perception accuracy of the plate fracture risk and facilitating practical application and promotion.

[0118] like Figure 6 As shown, the second aspect of this embodiment provides a virtual device for implementing the method for drawing a forming limit diagram on a plate according to the first aspect, comprising a strain data acquisition module, a mapping coordinate setting module, a shader setting module, a mapping coordinate transfer module, a rasterization processing module, a pixel color determination module, and a pixel color rendering module;

[0119] The strain data acquisition module is used to acquire the primary strain value and the secondary strain value of each grid vertex located on the outer surface of the model of the target plate three-dimensional model;

[0120] The mapping coordinate setting module is communicatively connected to the strain data acquisition module, and is used to set the corresponding primary strain value and secondary strain value as mapping coordinates to the corresponding vertex for each mesh vertex;

[0121] The shader setting module is used to set corresponding vertex shaders and pixel shaders for each mesh surface located on the outer surface of the model;

[0122] The texture coordinate transfer module is communicatively connected to the texture coordinate setting module and the shader setting module, and is used to transfer the texture coordinates of the mesh vertices located on the corresponding mesh face to the corresponding pixel shader for the vertex shader;

[0123] The rasterization processing module is communicatively connected to the texture coordinate transfer module and is used to rasterize the texture coordinates transferred to the pixel shader so that the pixel shader obtains pixel texture coordinates calculated by an interpolation algorithm in a rasterization process;

[0124] The pixel color determination module is communicatively connected to the rasterization processing module and is configured to extract, in the pixel shader, the pixel principal strain value and the pixel secondary strain value from the pixel map coordinates, and determine the pixel color for drawing the forming limit diagram in combination with the material parameters of the target sheet metal three-dimensional model;

[0125] The pixel color rendering module is communicatively connected to the pixel color determination module and is used to render the pixel color onto the outer surface of the model to obtain a forming limit diagram on the plate.

[0126] The working process, working details and technical effects of the aforementioned device provided in the second aspect of this embodiment can be referred to the method for drawing the forming limit diagram on the plate described in the first aspect, and will not be repeated here.

[0127] like Figure 7 As shown, the third aspect of this embodiment provides a computer device for executing the forming limit diagram drawing method on the plate as described in the first aspect, comprising a memory, a processor and a transceiver connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the forming limit diagram drawing method on the plate as described in the first aspect. For example, the memory may include, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a flash memory, a first-in first-out memory (FIFO) and / or a first-in last-out memory (FILO), etc.; the processor may include, but is not limited to, a microprocessor of the STM32F105 series. In addition, the computer device may also include, but is not limited to, a power module, a display screen and other necessary components.

[0128] The working process, working details and technical effects of the aforementioned computer device provided in the third aspect of this embodiment can be referred to the method for drawing the forming limit diagram on the plate described in the first aspect, and will not be repeated here.

[0129] A fourth aspect of this embodiment provides a computer-readable storage medium storing instructions including the method for drawing a forming limit diagram on a plate as described in the first aspect, wherein the computer-readable storage medium stores instructions that, when executed on a computer, execute the method for drawing a forming limit diagram on a plate as described in the first aspect. The computer-readable storage medium refers to a data storage medium and may include, but is not limited to, a floppy disk, an optical disk, a hard disk, a flash memory, a USB flash drive, and / or a memory stick. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device.

[0130] The working process, working details and technical effects of the aforementioned computer-readable storage medium provided in the fourth aspect of this embodiment can be referred to the method for drawing the forming limit diagram on the plate described in the first aspect, and will not be repeated here.

[0131] A fifth aspect of the present embodiment provides a computer program product, including a computer program or instructions, which, when executed by a computer, implements the method for drawing a forming limit diagram on a plate as described in the first aspect. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0132] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.< / vector>

Claims

1. A method for drawing a forming limit diagram on a plate, characterized in that: include: Obtaining the principal strain value and the secondary strain value of each mesh vertex located on the outer surface of the model of the target sheet metal three-dimensional model; For each mesh vertex, the corresponding principal strain value and the secondary strain value are set as mapping coordinates on the corresponding vertex; For each mesh patch located on the outer surface of the model, setting a corresponding vertex shader and pixel shader; For the vertex shader, passing the texture coordinates of the mesh vertices located on the corresponding mesh face to the corresponding pixel shader; rasterizing the texture coordinates passed to the pixel shader, so that the pixel shader obtains pixel texture coordinates calculated by an interpolation algorithm in a rasterization process; In the pixel shader, the pixel principal strain value and the pixel secondary strain value are extracted from the pixel map coordinates, and the pixel color used for drawing the forming limit diagram is determined in combination with the material parameters of the target sheet metal three-dimensional model; The pixel colors are rendered onto the outer surface of the model to obtain a forming limit diagram of the plate.

2. The method for drawing a forming limit diagram on a plate according to claim 1, characterized in that: The board forming limit diagram drawing method is implemented using a graphics drawing system based on Hoops, OpenGL, DirectX or Vulkan.

3. The method for drawing a forming limit diagram on a plate according to claim 1, characterized in that: When the Hoops-based graphics drawing system is used to implement the forming limit diagram drawing method on the plate, for each mesh vertex, the corresponding principal strain value and the secondary strain value are set together as mapping coordinates on the corresponding vertex, including: For each mesh vertex, the HC_Set_Parameter setting function is used to set the corresponding primary strain value and secondary strain value as mapping coordinates to the corresponding vertex.

4. The method for drawing a forming limit diagram on a plate according to claim 1, characterized in that: When the Hoops-based graphics rendering system is used to implement the forming limit diagram drawing method on the plate, corresponding vertex shaders and pixel shaders are set for each mesh facet located on the outer surface of the model, including: For each mesh patch located on the outer surface of the model, the HC_Set_Shader setting function is used to set the corresponding vertex shader and pixel shader.

5. The method for drawing a forming limit diagram on a plate according to claim 1, characterized in that: The material parameters include a plastic strain ratio value, a principal strain value when the secondary strain is zero, a strain hardening exponent value, a plate thickness, a safety region value and / or an allowable thickening interval value.

6. The method for drawing a forming limit diagram on a plate according to claim 1, characterized in that: Extracting pixel principal strain values and pixel secondary strain values from the pixel map coordinates and combining them with the material parameters of the target sheet metal three-dimensional model to determine the pixel color for drawing the forming limit diagram includes the following steps S61 to S68 performed in sequence: S61. Extracting the pixel primary strain value y and the pixel secondary strain value x from the pixel map coordinates; S62. Determine whether the pixel principal strain value y is less than or equal to the first curve function GreenLine(r,x) in the Keeler formula. If so, determine the color of the pixel to be assigned as a first color indicating a wrinkling risk area, wherein the first curve function GreenLine(r,x) is expressed as follows: Wherein, r represents the plastic strain ratio value in the material parameters of the target sheet three-dimensional model; S63. Determine whether the pixel principal strain value y is less than or equal to the second curve function BlueLine(x) in the Keeler formula. If so, determine the color of the pixel to be assigned as a second color for indicating being in a wrinkled area, wherein the second curve function BlueLine(x) is expressed as follows: BlueLine(x)=-x; S64. Determine whether the pixel principal strain value y is less than or equal to the third curve function PinkLine(r,x) in the Keeler formula. If so, determine that the color of the pixel to be assigned is the third color used to indicate a severely wrinkled area, wherein the third curve function PinkLine(r,x) is expressed as follows: S65. Determine whether the pixel principal strain value y is greater than or equal to the fourth curve function YellowLine(FLD0, x, safe region ), if so, the color of the pixel to be assigned is determined to be the fourth color for indicating a rupture risk area, wherein the fourth curve function YellowLine(FLD0,x,safe region ) is represented as follows: Where FLD0 represents the principal strain value in the material parameters when the secondary strain is zero, safety region represents a safe zone value within the material parameter; S66. Determine whether the pixel principal strain value y is greater than or equal to the fifth curve function RedLine(FLD0, x) in the Keeler formula. If so, determine that the color of the pixel to be assigned is the fifth color used to indicate that it is in a rupture area, wherein the fifth curve function RedLine(FLD0, x) is expressed as follows: S67. Determine whether the pixel principal strain value y is less than or equal to the sixth curve function DiagonalGreyLine (allowable thickening ,x) and whether the pixel secondary strain value x is greater than or equal to the seventh curve function VerticalGreyLine(allowable thickening ), if so, then determine that the color of the pixel to be assigned is the sixth color for indicating the effective strain deficiency area, wherein the sixth curve function DiagonalGreyLine (allowable thickening ,x) and the seventh curve function VerticalGreyLine(allowable thickening ) are respectively represented as follows: Where allowable thickening Indicates the allowable thickening range value in the material parameters; S68. Determine the pixel color used to draw the forming limit diagram as the pixel color to be assigned; The above steps S62 to S67 are allowed to be retained in any one of them or any combination thereof.

7. A device for drawing forming limit diagrams on a plate, characterized in that: It includes a strain data acquisition module, a mapping coordinate setting module, a shader setting module, a mapping coordinate transfer module, a rasterization processing module, a pixel color determination module and a pixel color rendering module; The strain data acquisition module is used to acquire the primary strain value and the secondary strain value of each grid vertex located on the outer surface of the model of the target plate three-dimensional model; The mapping coordinate setting module is communicatively connected to the strain data acquisition module, and is used to set the corresponding primary strain value and secondary strain value as mapping coordinates to the corresponding vertex for each mesh vertex; The shader setting module is used to set corresponding vertex shaders and pixel shaders for each mesh surface located on the outer surface of the model; The texture coordinate transfer module is communicatively connected to the texture coordinate setting module and the shader setting module, and is used to transfer the texture coordinates of the mesh vertices located on the corresponding mesh face to the corresponding pixel shader for the vertex shader; The rasterization processing module is communicatively connected to the texture coordinate transfer module and is used to rasterize the texture coordinates transferred to the pixel shader so that the pixel shader obtains pixel texture coordinates calculated by an interpolation algorithm in a rasterization process; The pixel color determination module is communicatively connected to the rasterization processing module and is configured to extract, in the pixel shader, the pixel principal strain value and the pixel secondary strain value from the pixel map coordinates, and determine the pixel color for drawing the forming limit diagram in combination with the material parameters of the target sheet metal three-dimensional model; The pixel color rendering module is communicatively connected to the pixel color determination module and is used to render the pixel color onto the outer surface of the model to obtain a forming limit diagram on the plate.

8. A computer device, characterized in that: The method comprises a memory, a processor and a transceiver which are communicatively connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the method for drawing a forming limit diagram on a plate as claimed in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores instructions, and when the instructions are executed on the computer, the method for drawing the forming limit diagram on the plate as described in any one of claims 1 to 6 is executed.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or the instruction is executed by a computer, the method for drawing a forming limit diagram on a plate according to any one of claims 1 to 6 is realized.

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