Structural parameter optimization design method and system based on sheet metal parts

Abstract

The invention relates to the technical field of structural design optimization, in particular to a structural parameter optimization design method and system based on sheet metal parts. The method comprises the following steps of calculating a normal included angle field by extracting a surface patch normal and a surface center coordinate of a CAD model, identifying a rib position transition area, and performing arc length calculation, curvature point analysis, step jump judgment and transition curve fitting based on a rib rotation angle coefficient. And the fatigue performance and the structural design optimization effect of the fitted curve are verified through a load cycle test. According to the method, the transition rib position area of the sheet metal part is accurately recognized through the normal included angle field, fine parameterization of the curve form is achieved in combination with the rib rotation angle coefficient, then step jump analysis and fitting are carried out, the stress streamline and structure transition design is optimized, the improvement effect of the method on the fatigue performance is verified through a load cycle test, and therefore the damage risk is effectively reduced, and the fatigue performance of the sheet metal part is improved. And the service life and reliability of the sheet metal part under the repeated load are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of structural design optimization, and in particular to a structural parameter optimization design method and system based on sheet metal parts. Background Art

[0002] Sheet metal components are widely used in industries such as automotive, aviation, and home appliances. Their structural design is directly related to the product's lightweight, strength, and durability. To improve structural efficiency, extend service life, and reduce manufacturing costs, existing technologies generally emphasize the optimization of sheet metal component structural parameters. This optimization can significantly improve component fatigue resistance and overall structural performance, especially under complex load conditions and repeated deformation.

[0003] However, in sheet metal structural design, rib transition areas often experience sudden changes in curvature, thickness variations, or inflection points in the loading path, making them prone to stress concentration and fatigue cracking. Existing technologies for optimizing these areas remain insufficient. This is primarily due to the following: most optimization design processes focus on global structural parameters and lack geometric identification and local fitting analysis for local transition areas (such as sections with rib changes), making it impossible to perform targeted design interventions in these areas. Furthermore, traditional methods focus on static analysis, lacking understanding of the impact of sudden changes in curvature on local load response and strain discontinuity, and lacking corresponding design optimization metrics and evaluation methods. Summary of the Invention

[0004] Based on this, it is necessary to provide a structural parameter optimization design method and system based on sheet metal parts to solve at least one of the above technical problems.

[0005] To achieve the above-mentioned purpose, a structural parameter optimization design method based on sheet metal parts is provided, the method comprising the following steps: Step S1: Obtaining sheet metal structural parameters input by the user; constructing a sheet metal CAD model based on the sheet metal structural parameters; Step S2: deriving the normal vectors and face center coordinates of all facets in the sheet metal part from the sheet metal part CAD model to calculate the normal angle field; determining the rib transition area of ​​the sheet metal part based on the normal angle field and a preset angle change threshold; Step S3: for any transition rib in the rib position transition area, determine the total transition arc length of the transition rib, and calculate the rib rotation coefficient at each curvature point of the transition rib based on the curvature point distribution of the transition rib; Step S4: performing a step jump analysis on the rib position transition area using the rib rotation coefficient, and performing rib position transition curve fitting for any curvature point of the transition rib based on the analysis results to obtain a rib position transition fitting curve; Step S5: Using the fitted rib position transition curve, the rib position transition area is tested under load cycles to verify the design optimization performance of the rib position transition area.

[0006] Preferably, determining the rib position transition area of ​​the sheet metal part according to the normal angle field and a preset angle change threshold includes: Traverse the normal angle field and mark the faces corresponding to the angles greater than or equal to the preset angle change threshold as transition candidate areas; For the transition candidate area, establish a transition adjacency undirected graph of the adjacent face sets that share edges or vertices with it; Extract the connected domain of the transition adjacency undirected graph to obtain several connected facet clusters, where each facet cluster is a candidate for a spatially continuous angle mutation region; For each connected cluster, the number of facets, total area, maximum angle value, and average angle gradient are calculated, and the transition candidate areas are screened to obtain the rib position transition area of ​​the sheet metal part.

[0007] Preferably, calculating the number of facets, the total area, the maximum angle value, and the average angle gradient, and performing region screening on the transition candidate region further includes: For each connected cluster, extract all face center coordinates and vertex coordinate sets of the face; The longest axis distance in the main direction and the shortest axis distance in the secondary direction of the connected cluster are confirmed by the face-centered coordinates and vertex coordinate sets; According to a preset threshold range, the number of facets, total area, maximum angle value, and average angle gradient obtained by calculation are used to perform geometric angle distribution screening on the transition candidate area to obtain a first screening area; The aspect ratio of the minimum enclosing rectangle of the connected cluster in three-dimensional space is calculated based on the longest axis distance in the main direction and the shortest axis distance in the secondary direction, and the transition candidate area is geometrically screened by the aspect ratio to obtain the second screening area; The intersection area of ​​the first screening area and the second screening area is screened to obtain the rib position transition area of ​​the sheet metal part.

[0008] Preferably, step S4 includes the following steps: Step S41: for each rib position transition region, extract the rib rotation coefficient sequence within the region and organize it into discrete angle change data in spatial order; Step S42: Perform step jump detection on the rotation coefficient sequence, identify the position interval where the angle changes suddenly, and mark it as a potential jump segment; Step S43: In each potential jump segment, based on the smooth change trend of the rib position transition area, extract the curvature points representing the transition characteristics and eliminate noise interference; Step S44: For any selected transition rib, a set of control points is collected based on the curvature point, including the first and last ends and the middle key points of the potential jump segment corresponding to the point, and curvature smoothing is performed on each potential jump segment according to the control point set to obtain a smoothed jump curve segment; Step S45: Mapping the smoothed jump curve segment back to the rib position transition region to perform transition curve fitting to obtain a rib position transition fitting curve.

[0009] Preferably, step S44 includes the following steps: Step S441: For any selected transition rib, extract the curvature key points of the beginning, end, and middle mark of the segment within the range of its potential jump segment, and construct a control point set for the jump segment; Step S442: Arrange the control point set of each jump segment in a logical order and calculate the arc length distance between each point; Step S443: performing local smooth interpolation on the potential jump segment based on the control point set, and performing window filtering on the jump segment area adjacent to the control point during the smoothing process to obtain a smoothed jump curve segment; Step S444: confirming the curve endpoints of the jump curve segment after the primary smoothing, and introducing a curve transition zone according to the arc length distance to obtain the jump curve segment after the secondary smoothing.

[0010] Preferably, if the distance between any two adjacent control points exceeds a preset threshold, the intermediate compensation point inserted into the interval further includes: If the distance between any two adjacent control points exceeds a preset threshold, then for any pair of adjacent control points, the number of intermediate compensation points is determined based on the spatial distance and shape changes of the adjacent control points; Based on the number of intermediate compensation points, the intermediate compensation points are evenly distributed along the curve direction between two adjacent control points; For each intermediate compensation point, the coordinates of the intermediate compensation point in three-dimensional space are calculated by referring to the positions of its adjacent points and the direction of the curve; According to coordinate synchronization, each intermediate compensation point is assigned a curve curvature value consistent with its surrounding adjacent control points, and is sequentially inserted into the jump segment and marked as an intermediate compensation point.

[0011] Preferably, the load cycle setting process includes: constructing a standard loading condition that matches the rib transition area, setting the amplitude, frequency and duration parameters of the load cycle, wherein: the amplitude range of the load cycle is set to 20MPa to 80MPa; the frequency of the load cycle is set to 0.5Hz to 5Hz; the setting of the duration parameters includes: the single loading time lasts 5 seconds to 20 seconds, and the total number of cycles is not less than 5000 times or until the critical fatigue state is reached.

[0012] Preferably, using the fitted rib position transition curve to test the rib position transition area under load cycles includes: The rib transition area is tested based on a set load cycle. During the loading process, the strain response data and microcrack growth behavior of the transition area are collected in real time, and key indicators are recorded. These key indicators include: local strain peak, number of cycles in the initial stage of crack growth, and the rate of decrease in structural stiffness under cyclic loading. After completing the preset number of cycles, non-destructive testing is performed on the reinforcement transition area to identify micro-damage or local instability characteristics within the structure. The final accumulated number of cycles and key indicators are judged based on the structural failure judgment criteria to obtain comparative results; the cyclic load resistance of the reinforcement transition area under the optimized design is evaluated, thereby generating load response data and fatigue life prediction reports.

[0013] In this specification, a sheet metal-based structural parameter optimization design system is provided for executing the above-mentioned sheet metal-based structural parameter optimization design method. The sheet metal-based structural parameter optimization design system includes: The model building module is used to obtain the sheet metal structural parameters input by the user; and build a sheet metal CAD model based on the sheet metal structural parameters; The region screening module is used to derive the normal vectors and face center coordinates of all facets in the sheet metal part from the sheet metal part CAD model to calculate the normal angle field; based on the normal angle field and the preset angle change threshold, the rib transition area of ​​the sheet metal part is determined; The rotation angle calculation module is used to determine the total transition arc length of any transition rib in the rib transition area, and calculate the rib rotation angle coefficient at each curvature point of the transition rib based on the distribution of the curvature points of the transition rib; The curve fitting module is used to perform step jump analysis on the rib position transition area through the rib rotation coefficient, and to fit the rib position transition curve for the curvature point of any transition rib based on the analysis results to obtain the rib position transition fitting curve; The optimization test module is used to use the fitted rib transition curve to test the rib transition area under load cycles to verify the design optimization performance of the rib transition area.

[0014] The present invention has the following beneficial effects: First, by extracting the face normal vector and face center coordinates, calculating the normal angle field, and combining it with a preset threshold, the transition rib area on the sheet metal part can be accurately located, avoiding the traditional rough estimation based on macroscopic geometric features and improving the reliability and repeatability of recognition. Simultaneously, the total transition arc length and curvature point distribution of any transition rib are quantitatively analyzed, and the rib rotation coefficient at each curvature point is calculated, achieving a refined parameterized description of the curve morphology, providing a solid data foundation for subsequent step jump analysis and curve fitting.

[0015] Second, using the rib rotation coefficient to perform a step-jump analysis of the transition region not only reveals the stress concentration trend caused by local geometric changes but also quantitatively evaluates the impact of each curvature point on the overall stiffness distribution, providing a scientific basis for optimizing the design. Based on the step-jump analysis results, a curve fitting is performed on the curvature points of the transition rib. The resulting rib position transition fitting curve better matches the stress streamlines and deformation trends under actual loading conditions, thus guiding the design of smooth transitions in sheet metal structures.

[0016] Third, by simulating load cycle tests under real-world conditions, the effect of the fitted transition curve on regional fatigue performance can be directly verified. This can identify potential fatigue damage points in the early design phase, significantly reducing subsequent trial production and maintenance costs. Combining the above refined identification, parametric analysis, and experimental verification, the method of this invention can effectively reduce stress concentration and material loss in the transition region, significantly improving the fatigue life and reliability of sheet metal parts under repeated load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the steps of a structural parameter optimization design method based on sheet metal parts; Figure 2 A flowchart of the steps for obtaining the rib transition area of ​​a sheet metal part provided in one embodiment of the present application; Figure 3 This is a structural design diagram of a structural parameter optimization design method based on sheet metal parts; Figure 4 This is a schematic diagram of a structural design optimization method based on structural parameter optimization design of sheet metal parts; Figure 5 A functional module diagram of a structural parameter optimization design system based on sheet metal parts provided in one embodiment of the present application; The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0018] The following is a clear and complete description of the technical method of the present invention in conjunction with the accompanying drawings. It is obvious that the embodiments described are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts are within the scope of protection of the present invention.

[0019] In addition, the accompanying drawings are merely schematic illustrations of the present invention and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and thus repetitive descriptions thereof will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor and / or microcontroller approaches.

[0020] It should be understood that although the terms "first," "second," and the like may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used solely to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the exemplary embodiments. The term "and / or" as used herein includes any and all combinations of one or more of the listed associated items.

[0021] To achieve this, please refer to Figures 1 to 5 , a structural parameter optimization design method based on sheet metal parts, the method comprising the following steps: Step S1: Obtaining sheet metal structural parameters input by the user; constructing a sheet metal CAD model based on the sheet metal structural parameters; In one embodiment, on a sheet metal design workstation, a user inputs key structural parameters of a sheet metal part through a graphical human-computer interface (GUI), including but not limited to: sheet length L, sheet width W, sheet thickness T, bending radius R, bending angle θ, material type, etc.; the GUI interface is provided by a parameter acquisition module pre-deployed on a local server or in the cloud, and the parameters are transmitted to a CAD modeling module through a secure communication interface for subsequent model generation.

[0022] In one implementation of this embodiment, the parameter acquisition module performs format check and legality verification on the parameters input by the user: the length parameters L and W are limited to the range of 10mm to 1000mm; the thickness T is limited to the range of 0.5mm to 5mm; the bending radius R is limited to the range of 1mm to 10mm; the bending angle θ is limited to the range of 30° to 180°; after verification, the parameter acquisition module packages the standardized structural parameters into XML or JSON format data and pushes it to the subsequent CAD modeling engine.

[0023] The CAD modeling module is based on parametric modeling technology, calling on a pre-defined sheet metal template library and material database to perform the following operations: reading standardized structural parameters and initializing the base sheet metal geometry; assigning corresponding material entities to the model according to the sheet metal thickness T and the material mechanical properties; automatically generating bending features based on the bending radius R and bending angle θ, and creating chamfers or fillets at the corresponding positions; after all bending features are generated, performing post-processing operations such as edge rounding and hole generation on the entire sheet metal part; and finally outputting a complete 3D CAD model that meets user requirements and saving it in a local or cloud file server in a neutral format such as STEP or Parasolid.

[0024] It should be noted that, in this embodiment, the data transmission between the parameter acquisition module and the CAD modeling module adopts the RESTful API method, which supports HTTPS encrypted transmission; all input parameters can be managed through the version control system to facilitate the tracing of historical designs; after the design is completed, the user can use the export function to obtain the configuration document and CAD model file with one click for subsequent simulation analysis or CNC machining.

[0025] Step S2: deriving the normal vectors and face center coordinates of all facets in the sheet metal part from the sheet metal part CAD model to calculate the normal angle field; determining the rib transition area of ​​the sheet metal part based on the normal angle field and a preset angle change threshold; In one embodiment, the CAD file parsing module reads the 3D sheet metal CAD model in STEP / Parasolid format and calls the topology analysis engine to extract a mesh list consisting of all triangular (or quadrilateral) facets on the outer surface. Each facet consists of three or four vertex coordinates { , , (, )}. For each face in the mesh list, the unit normal vector is calculated using the cross multiplication method: If it is a four-sided face, first split it into two triangular faces and calculate them separately, or use the diagonal average method to get the normal. For each face, calculate the face center coordinates by the vertex coordinate average method: ,in is the number of patch vertices (3 or 4). For each pair of adjacent patches in the mesh list (identified by shared edges), calculate the angle between their normal vectors: , all angle values Map to the corresponding face center position to generate the normal angle field data structure - a spatially discrete angle field. Preset face normal angle change threshold Δ (For example, it can be adjusted within the range of 5° to 15°). The threshold is determined by the user according to material processing requirements or simulation results and stored in the parameter library.

[0026] Scan all the patches in the normal angle field and mark the face centers C that meet the following conditions as transition candidates: the angle with any adjacent patch is >Δ The number of consecutive facets that meet the conditions must be no less than the preset connectivity threshold N_min (e.g., three or more). Based on connectivity analysis (depth-first or breadth-first search), all transition candidate facets are clustered into connected clusters, which serve as the rib transition regions for the sheet metal part. After identification, the region calibration module packages the connected cluster face center coordinates and corresponding normal angle values ​​into JSON format and transmits them to the 3D visualization platform. The visualization client then highlights or renders the transition rib regions in different colors to facilitate subsequent design review or process parameter optimization.

[0027] Step S3: for any transition rib in the rib position transition area, determine the total transition arc length of the transition rib, and calculate the rib rotation coefficient at each curvature point of the transition rib based on the curvature point distribution of the transition rib; In one embodiment, the transition rib recognition module reads the calibrated transition rib surface centroid data and automatically fits a smooth centerline along the rib transition region in the 3D CAD model. This centerline consists of a series of equally spaced nodes, with node spacing configurable in the interface (e.g., 1 mm by default) to ensure the required resolution for subsequent arc length and curvature analysis.

[0028] On this centerline, the actual distance between each pair of adjacent nodes is measured using a high-precision distance measurement device or the CAD built-in measurement engine and recorded as the local segment length. After the segment length measurement is completed, the arc length statistics module accumulates all the local segment lengths to obtain the total transition arc length of the transition rib. This value is then converted to two decimal places with millimeter accuracy as the actual curve distance from the rib's starting point to its end point.

[0029] A fixed-length detection window (such as 5 mm) is slid along the center line, and the trend of the curve inclination change is evaluated in each window. The position where the curvature changes significantly is automatically marked as the curvature point. In the area where the bending is concentrated, the system reduces the minimum spacing between the curvature points to 50% of the original spacing to increase the sampling density; in the flat area, it is relaxed to the regular node spacing to reduce the amount of calculation. For each identified curvature point, the system combines the inclination change amplitude between the point and its front and rear adjacent nodes to generate the corresponding rib angle coefficient. This coefficient reflects the deviation of the local bending strength from the overall smoothness of the rib. After the coefficient is calculated, it is limited to the range of 0.0 to 1.0 through normalization processing to ensure that transition ribs of different lengths or different curvatures are comparable.

[0030] The total transition arc length and the list of rib rotation coefficients for all curvature points are combined to create a unified data structure (e.g., a JSON object) containing the rib identifier, arc length value, curvature point index, and corresponding rotation coefficient. This structure is pushed to the forming process optimization and strength simulation modules via a RESTful API for mold parameter adjustment, material stress analysis, and quality assessment. Furthermore, the visualization platform uses this data to render the rotation coefficients as color bands or height maps on the 3D model, visually displaying areas of concentrated localized bending.

[0031] Step S4: performing a step jump analysis on the rib position transition area using the rib rotation coefficient, and performing rib position transition curve fitting for any curvature point of the transition rib based on the analysis results to obtain a rib position transition fitting curve; In one embodiment, the rib rotation coefficients corresponding to each curvature point along the center line of a transition rib are obtained from the aforementioned steps and arranged into a one-dimensional coefficient sequence in the order of the arc length of the curve. The sequence uses the cumulative arc length of each sampling point on the center line as the horizontal axis index and the corresponding rib rotation coefficient as the vertical axis value, providing the original data basis for subsequent jump analysis and fitting. In order to identify the location of local morphological mutations on the transition rib, the system performs differential processing on the rib rotation coefficient sequence to obtain the coefficient change value between adjacent sampling points, and compares it with the preset jump threshold. When the change value at a certain position exceeds the threshold, it is determined to be a step jump point. The system records all jump points according to the center line arc length position to guide subsequent fitting segmentation.

[0032] Based on the detected jump point positions, the system divides the entire rib rotation coefficient sequence into several continuous segments. The coefficient changes in each segment are relatively smooth, without mutations; the segment boundary is the location of the jump point. This segmentation method ensures that there is no direct fitting across segments at the morphological mutation point, avoiding excessive smoothing or oscillation. For each smooth segment, the system calls the curve fitting module and uses cubic spline or other smooth interpolation methods to fit the coefficients and arc length data in the segment to generate a continuous and smooth transition curve. The fitting curves of each segment are naturally connected at the jump point but are not forced to be smoothed to retain the local mutation characteristics. During the fitting process, the system automatically adjusts the number of control points and the fitting accuracy to ensure that the entire curve maintains both smoothness and reflects local changes within the allowable error range.

[0033] After completing the fitting of all segments, the system concatenates the fitting curves of each segment in order of centerline arc length to obtain the final fitting curve for the entire transition rib. This curve is encapsulated as structured data, either as a list of discrete points or a parametric expression, and pushed to the visualization platform and forming process optimization module via a communication interface. On the visualization side, the fitting curve is displayed alongside the original sampling points, allowing designers to intuitively assess curve smoothness and localized mutations, allowing them to adjust mold bending strategies or simulation parameters accordingly.

[0034] Step S5: Using the fitted rib position transition curve, the rib position transition area is tested under load cycles to verify the design optimization performance of the rib position transition area.

[0035] In one embodiment, before the test, the forming process optimization module and the strength simulation module collaborate to generate a load cycle plan. The plan includes: the amplitude range of the cyclic load (such as from the lowest bending stress to the highest bending stress), the cycle frequency (such as 1Hz to 5Hz), the total number of cycles (such as 10,000 to 100,000 times), and environmental conditions such as test temperature and humidity. All parameters are preset by the user in the interface, and can also be automatically recommended based on material properties. The specimen containing the transition rib area is fixed in the upper and lower clamps of a dedicated fatigue testing machine to ensure that the transition area is uniformly stressed. Strain gauges, micro-displacement sensors or optical tracking markers are installed at key fitting positions on the transition rib curve to monitor local strain and micro-deformation in real time. The sensor data is connected to the test control host through a high-speed data acquisition device.

[0036] The test machine is started according to the preset cycle plan, so that the transition rib undergoes forward bending and reverse rebound in sequence. The test control host collects sensor data in real time at a microsecond sampling rate and monitors the load, displacement and strain curves to ensure that the load output and inflection point position of each cycle are highly consistent with the fitting curve. If an abnormal strain or early crack signal exceeding the warning threshold is detected, the system automatically pauses the test and saves the current data. After the test is completed, the collected full-process load-strain-displacement data is imported into the data processing module. The module first filters and reduces noise on the original signal, and then slices the data according to the position of the curvature point to obtain the strain history curve at each curvature point. Based on the relationship between the number of cycles and the strain amplitude, combined with the Miner linear cumulative damage model or other life prediction models, the degree of fatigue damage accumulation and the expected number of failure cycles at each curvature point are evaluated. The fatigue life analysis results are associated with the corresponding positions of the transition rib fitting curve and visualized to generate a color band or life cloud map to intuitively display the vulnerable parts and life distribution differences in the transition area.

[0037] As an example of the present invention, refer to Figure 2 As shown, in this example, step S2 includes: Step S21: traverse the normal angle field, and mark the faces corresponding to the angles greater than or equal to a preset angle change threshold as transition candidate regions; Step S22: for the transition candidate region, establish a transition adjacency undirected graph of the set of adjacent facets that share edges or vertices with the transition candidate region; Step S23: extracting the connected domain of the transition adjacency undirected graph to obtain a number of connected face clusters, where each face cluster is a candidate for a spatially continuous angle mutation region; Step S24: For each connected cluster, calculate the number of facets, total area, maximum angle value, and average angle gradient, and perform region screening on the transition candidate regions to obtain the rib position transition region of the sheet metal part.

[0038] In one embodiment, reference Figure 3 First, the normal vector of each facet in the sheet metal CAD model is calculated, and the normal angle field is constructed by combining the normal angles between adjacent faces. Since the rib transition area in the sheet metal is usually accompanied by obvious local geometric mutations, its normal angle presents a sudden distribution in space. Therefore, the significant change in the normal angle can be used to preliminarily judge the potential transition area. To this end, a threshold value θ for the angle change is set, for example, 30 degrees. When the normal angle between adjacent faces is greater than or equal to this threshold, it can be considered that there is a potential transition structure here. These faces that meet the conditions are marked as transition candidate areas for subsequent fine recognition processing.

[0039] All faces marked as transition candidates in the CAD model are treated as nodes in a graph. If any two faces share an edge or vertex, undirected edges are established between them, thus forming a transition adjacency undirected graph based on face adjacency relationships. This graph effectively reflects the spatial structural continuity between candidate faces and helps identify the true topological connections between rib transition regions in the model. A standard graph traversal algorithm (such as depth-first search or breadth-first search) is used to extract all connected domains from the constructed transition adjacency undirected graph. Each connected domain consists of a set of spatially adjacent faces, representing a geometrically continuous region with a sudden change in angle. Since sheet metal ribs are typically spatially connected, these face clusters can be used as candidate rib transition regions, providing a basis for subsequent judgment.

[0040] For each connected cluster, the number of facets and total area it contains are counted to determine its structural scale. The maximum normal angle between facets within the region and the average gradient of the angle change of all adjacent facets are calculated to assess the degree of internal geometric mutation. If the number of facets in a connected cluster is lower than the set threshold or its average angle gradient is lower than the set gradient threshold, the region is considered to have no obvious transition characteristics and is not included in the final rib transition region. After this screening process, the remaining regions are the rib transition regions in the sheet metal part that have geometric mutation characteristics and are spatially continuous, which can be used for subsequent structural optimization, load analysis, or production process adjustments.

[0041] Preferably, calculating the number of facets, the total area, the maximum angle value, and the average angle gradient, and performing region screening on the transition candidate region further includes: For each connected cluster, extract all face center coordinates and vertex coordinate sets of the face; The longest axis distance in the main direction and the shortest axis distance in the secondary direction of the connected cluster are confirmed by the face-centered coordinates and vertex coordinate sets; According to a preset threshold range, the number of facets, total area, maximum angle value, and average angle gradient obtained by calculation are used to perform geometric angle distribution screening on the transition candidate area to obtain a first screening area; The aspect ratio of the minimum enclosing rectangle of the connected cluster in three-dimensional space is calculated based on the longest axis distance in the main direction and the shortest axis distance in the secondary direction, and the transition candidate area is geometrically screened by the aspect ratio to obtain the second screening area; The intersection area of ​​the first screening area and the second screening area is screened to obtain the rib position transition area of ​​the sheet metal part.

[0042] In one embodiment, for each connected cluster, the coordinates of the face centers or vertices of all the facets it contains are first extracted to characterize the distribution of the region in three-dimensional space. Based on the extracted coordinate point set, principal component analysis (PCA) or spatial axis projection is used to determine the primary and secondary directions of the connected cluster in three-dimensional space. The primary direction is the direction with the widest distribution of the point cluster, and its corresponding axial distance is the longest wheelbase. The secondary direction is the direction with the narrowest distribution of the point cluster, and its corresponding axial distance is the shortest wheelbase. Then, based on preset angle and area screening thresholds, a comprehensive assessment is performed on the number of facets, total area, maximum angle value, and average angle gradient of each connected cluster. If all of these indicators for a cluster fall within a preset reasonable range, it is considered to have rib position transition characteristics in its geometric angle distribution and is retained as the first screening region. Next, based on the cluster's longest wheelbase in the primary direction and shortest wheelbase in the secondary direction, its minimum bounding rectangle (MBR) is constructed, and its aspect ratio is calculated. Empirically, typical rib transition regions exhibit elongated shapes, with aspect ratios generally exceeding a certain empirical threshold (e.g., 2.0). Based on this, all connected clusters are geometrically screened to obtain a second screening region that meets this aspect ratio requirement. Finally, the first and second screening regions are intersected, retaining only those connected clusters that meet both geometric angle distribution characteristics and geometric profile morphology characteristics as the final sheet metal rib transition regions. This dual screening strategy effectively eliminates misidentified regions due to unusual interference or sporadic angle changes, thereby accurately identifying structural regions with typical transition morphologies and geometric regularity.

[0043] Preferably, step S4 includes the following steps: Step S41: for each rib position transition region, extract the rib rotation coefficient sequence within the region and organize it into discrete angle change data in spatial order; Step S42: Perform step jump detection on the rotation coefficient sequence, identify the position interval where the angle changes suddenly, and mark it as a potential jump segment; Step S43: In each potential jump segment, based on the smooth change trend of the rib position transition area, extract the curvature points representing the transition characteristics and eliminate noise interference; Step S44: For any selected transition rib, a set of control points is collected based on the curvature point, including the first and last ends and the middle key points of the potential jump segment corresponding to the point, and curvature smoothing is performed on each potential jump segment according to the control point set to obtain a smoothed jump curve segment; Step S45: Mapping the smoothed jump curve segment back to the rib position transition region to perform transition curve fitting to obtain a rib position transition fitting curve.

[0044] In one embodiment, reference Figure 4For each rib structure within the transition region, a continuous sequence of rotation angle coefficients is calculated based on the normal angle information between adjacent facets on its skeleton line or surface curve. This sequence is then organized into spatially continuous discrete angle change data based on the spatial layout order of the ribs along their length, reflecting the degree of rib turning at different locations. The local change rate of the angle sequence is analyzed using the first-order difference or sliding window coefficient of variation method. When the angle change value within a certain segment exceeds the preset jump threshold, the segment is judged to have an angle mutation feature, i.e., a potential jump segment. The starting and ending points of each potential jump segment are marked as the jump segment boundary.

[0045] A curvature analysis method is used to perform a fine-grained scan of the geometric contours within the potential jump segment, extracting points with significant local curvature changes as curvature points. Combined with the curvature smoothness requirements of continuous segments within the region, interference points such as single-point mutations and sporadic fluctuations that may be caused by modeling errors or sampling noise are eliminated, retaining key feature points with practical transition significance in the structure. The control point set can be modeled using Bezier curves, B-splines, or other continuous curves. By fitting the start point, end point, and several intermediate curvature points, a smooth curve with continuous derivatives is formed, enabling it to accurately express the transition trend of the jump segment in space and avoid sharp changes in curvature. By back-mapping the generated jump curve segment in the original three-dimensional model space and calibrating the fitting error between the fitted curve and the actual rib contour, the fitting result is made to better fit the actual rib position geometry.

[0046] Preferably, step S44 includes the following steps: Step S441: For any selected transition rib, extract the curvature key points of the beginning, end, and middle mark of the segment within the range of its potential jump segment, and construct a control point set for the jump segment; Step S442: Arrange the control point set of each jump segment in a logical order and calculate the arc length distance between each point; Step S443: performing local smooth interpolation on the potential jump segment based on the control point set, and performing window filtering on the jump segment area adjacent to the control point during the smoothing process to obtain a smoothed jump curve segment; Step S444: confirming the curve endpoints of the jump curve segment after the primary smoothing, and introducing a curve transition zone according to the arc length distance to obtain the jump curve segment after the secondary smoothing.

[0047] In one embodiment, for any selected transition rib, firstly, the first and last endpoints of the segment are extracted within the identified potential jump segment. , end point And several curvature key points marked in the middle , construct the control point set of the jump segment , used for subsequent curvature smooth interpolation. All points in the , are logically sorted according to their natural order in the spatial direction of the rib line, and the arc length distance is calculated based on the 3D coordinate difference between adjacent control points , and get the distance sequence , for the subsequent smoothing weight allocation and transition band width determination.

[0048] Control point set and its corresponding distance sequence As a benchmark, local smooth interpolation is performed for each potential jump segment: at each control point Define the window length within the neighborhood of (It can be taken as the ratio of the sum of the distances between two adjacent segments), apply a filter (such as moving average or Gaussian filter) to the original curvature data within the window on the jump segment to remove high-frequency noise; use curve fitting methods such as cubic B-spline or Bezier curve to interpolate the point set after window filtering to construct a point with Continuous smooth transition curve segment S¹.

[0049] Confirm the jump curve segment after smoothing The endpoints of the curve , and introduce a transition zone at each end point according to the pre-calculated arc length sequence ( ,in is the empirical coefficient), and a gradually weakening window function (such as cosine weighting) is used to perform a secondary smoothing process on the curvature gradient in the transition zone to obtain the final secondary smooth jump curve segment. .Will Mapping back to the original rib position transition area completes the curvature smoothing of the potential jump segment and provides a high-precision control curve for the transition curve fitting of the entire rib line.

[0050] Preferably, for each jump segment control point set, arranging the points in a logical order includes: For each jump segment control point set, the three-dimensional Euclidean distance between adjacent control points is calculated according to the spatial projection order of the control points on the transition rib, and the distance parameter of each control point is accumulated; Normalize the distance parameter to a parameterized coordinate in the interval [0,1] as the position weight of each control point; Each control point in the control point set is sorted in ascending order and checked for proximity based on the position weight. If the distance between any two adjacent control points exceeds a preset threshold, an intermediate compensation point in the interval is inserted to perform a logical order point arrangement.

[0051] In one embodiment, to ensure continuity and spatial logical order in the curvature fitting process of the jump segment, the control point set of each jump segment needs to be arranged in a logical order before constructing the control point curve. Specifically, the following steps are performed: for each jump segment, the three-dimensional Euclidean distance between adjacent control points is calculated according to the spatial projection order of the control points on the transition rib, and the distance parameter of each control point is accumulated; the distance parameter is normalized to a parameterized coordinate in the interval [0, 1] as the position weight of each control point; each control point in the control point set is sorted in ascending order and the neighbor distance is checked based on the position weight. If the distance between any two adjacent control points exceeds a preset threshold, an intermediate compensation point in the interval is inserted to perform a logical order point arrangement.

[0052] Specifically, for the set of control points in the transition segment, the absolute coordinates of each control point in 3D space are first extracted. These points are then projected onto the reference direction of the transition bar (which can be the principal axis or the principal direction of curvature) to obtain the linear sequence of the control points. Based on this spatial sequence, the 3D Euclidean distances between adjacent control points are calculated and accumulated to form a distance parameter representing the "cumulative path length" of each control point along the entire transition bar.

[0053] Next, the cumulative path length is normalized to the interval [0, 1] and used as the parameterized position weights of the control points. This normalization helps maintain the balance and controllability of the curvature transition during the curve fitting or interpolation phase. The control points are sorted in ascending order using the parameterized position weights to ensure that their spatial arrangement conforms to the logical continuity of the transition direction.

[0054] After sorting, the control point sequence is further verified to determine whether the Euclidean distance between any two adjacent control points exceeds a preset distance threshold (e.g., a certain proportional coefficient of the rib length, such as 0.1 × L). If the distance between a pair of control points exceeds the threshold, it indicates that the area has sparse sampling or a sudden transition. In this case, an intermediate compensation point is inserted between the two points. The intermediate compensation point can be obtained through linear interpolation or curvature trend extrapolation to enhance the uniformity of the control point distribution and the stability of the fitting curve.

[0055] Preferably, if the distance between any two adjacent control points exceeds a preset threshold, the intermediate compensation point inserted into the interval further includes: If the distance between any two adjacent control points exceeds a preset threshold, then for any pair of adjacent control points, the number of intermediate compensation points is determined based on the spatial distance and shape changes of the adjacent control points; Based on the number of intermediate compensation points, the intermediate compensation points are evenly distributed along the curve direction between two adjacent control points; For each intermediate compensation point, the coordinates of the intermediate compensation point in three-dimensional space are calculated by referring to the positions of its adjacent points and the direction of the curve; According to coordinate synchronization, each intermediate compensation point is assigned a curve curvature value consistent with its surrounding adjacent control points, and is sequentially inserted into the jump segment and marked as an intermediate compensation point.

[0056] In one embodiment, during the logical sequence arrangement of the control point set of a transition segment, if the spatial distance between any two adjacent control points exceeds a preset threshold, intermediate compensation points are inserted within this interval to ensure uniform distribution of the control points and continuity of the curve fitting. This process includes the following steps: if the distance between any two adjacent control points exceeds the preset threshold, for any pair of adjacent control points, the number of intermediate compensation points is determined based on the spatial distance and shape variation of the adjacent control points; based on the number of intermediate compensation points, the intermediate compensation points are evenly distributed along the curve direction between the two adjacent control points; for each intermediate compensation point, the coordinates of the intermediate compensation point in three-dimensional space are calculated by referring to the positions of its adjacent points and the direction of the curve; based on the coordinates, each intermediate compensation point is synchronously assigned a curve curvature value consistent with its surrounding adjacent control points, and each intermediate compensation point is sequentially inserted into the transition segment and marked as an intermediate compensation point.

[0057] Specifically, for any pair of adjacent control points and , first calculate the three-dimensional Euclidean distance between them When the distance is greater than the set threshold (For example, 10% of the total length of the transition section), further determine the shape change within this interval, such as the local curvature change rate or the normal angle change rate. If the curvature changes significantly, increase the density of compensation points. Based on the above distance and change indicators, determine the number of intermediate compensation points to be inserted. , it is preferred to distribute the number of supplementary points in proportion to the distance length.

[0058] Based on the determined number of compensation points, and The connecting line segment is divided into equidistant segments, and the compensation points are evenly distributed on the segment. In order to ensure the rationality of the compensation points in the direction of the spatial curve and avoid the generation of unrealistic broken line effects, it is necessary to further perform interpolation optimization based on the direction of the curve between the two points.

[0059] For each intermediate compensation point By using linear, Bezier, or B-spline interpolation, the coordinates of the position in 3D space are accurately calculated, combining the 3D coordinates of its left and right adjacent control points with the curve trend. The curvature information of its neighboring points is also referenced to assign a curvature value (such as the local normal angle and derivative rate of change) consistent with the curve trend at that location, ensuring a continuous transition between the geometric characteristics of the compensation point and the original control point. Finally, the generated intermediate compensation points are inserted into the jump segment control point set in their logical order and marked as intermediate compensation points.

[0060] Preferably, the load cycle setting process includes: constructing a standard loading condition that matches the rib transition area, setting the amplitude, frequency and duration parameters of the load cycle, wherein: the amplitude range of the load cycle is set to 20MPa to 80MPa; the frequency of the load cycle is set to 0.5Hz to 5Hz; the setting of the duration parameters includes: the single loading time lasts 5 seconds to 20 seconds, and the total number of cycles is not less than 5000 times or until the critical fatigue state is reached.

[0061] In one embodiment, a standard loading condition matching the rib transition region is constructed by setting a cyclic load amplitude of 20MPa to 80MPa, a frequency of 0.5Hz to 5Hz, and a loading duration of 5 to 20 seconds. This not only fully simulates various loading scenarios encountered in actual service but also effectively verifies the fatigue performance optimization effect of the transition curve design. The total number of cycles is no less than 5000 or until the critical fatigue state is reached, ensuring high reliability, repeatability, and engineering adaptability of the test, providing a scientific basis for subsequent structural optimization.

[0062] In another embodiment, the load cycle can be set to a higher-intensity and more complex loading condition. For example, the cyclic load amplitude range can be expanded to 30 MPa to 100 MPa, the frequency can be set to 0.2 Hz to 10 Hz, and a stepped or random amplitude loading mode can be introduced. Duration parameters can be set, including: the single loading time can be adjusted to 3 to 30 seconds based on the actual structural response, and the total number of cycles can be set to more than 10,000 or automatically terminated based on the accumulated fatigue damage results monitored in real time. This setting helps evaluate the durability performance of the rib transition area under extreme or complex service conditions, enhances the robustness verification capability of the structural design, and more closely meets the requirements for transition design stability under actual operating conditions.

[0063] Preferably, using the fitted rib position transition curve to test the rib position transition area under load cycles includes: The rib transition area is tested based on a set load cycle. During the loading process, the strain response data and microcrack growth behavior of the transition area are collected in real time, and key indicators are recorded. These key indicators include: local strain peak, number of cycles in the initial stage of crack growth, and the rate of decrease in structural stiffness under cyclic loading. After completing the preset number of cycles, non-destructive testing is performed on the reinforcement transition area to identify micro-damage or local instability characteristics within the structure. The final accumulated number of cycles and key indicators are judged based on the structural failure judgment criteria to obtain comparative results; the cyclic load resistance of the reinforcement transition area under the optimized design is evaluated, thereby generating load response data and fatigue life prediction reports.

[0064] In one embodiment, a transition region model formed from the fitted rib position transition curves is used to set specific load cycle parameters, including upper and lower load limits, loading frequency, and total number of cycles, to simulate the stress conditions under real-world conditions. This transition region model is mounted on a dedicated test platform, and cyclic loading is applied to it via a servo-controlled loading device.

[0065] During the cyclic loading process, strain gauges, displacement sensors, and digital image correlation (DIC) sensors were used to collect real-time strain response data from the rib transition zone, simultaneously monitoring the initiation and propagation of microcracks on the surface and near the surface. Key performance indicators recorded included: peak local strain; number of cycles corresponding to the initial stage of crack propagation; and the rate of decrease in structural stiffness under cyclic loading.

[0066] After completing the preset number of load cycles, non-destructive testing (NDT) such as ultrasonic scanning, eddy current testing, or X-ray imaging is performed on the rib transition area to identify any instability features such as micro-damage, material delamination, or local buckling within the structure.

[0067] Key metrics such as peak strain, crack evolution behavior, stiffness degradation rate, and cumulative number of cycles recorded are compared with structural failure criteria to comprehensively assess the cyclic load-bearing performance of the rib transition region under the current optimized design. Load response data and fatigue life prediction reports are generated based on historical data and regression models to assess the reliability of the structure under long-term service conditions. If the assessment results indicate fatigue performance bottlenecks in certain areas, these are further fed back into the rib curve fitting and optimization design process, forming a closed-loop structural optimization loop based on test verification.

[0068] like Figure 5 , which is a functional module diagram of a structural parameter optimization design system based on sheet metal parts provided by an embodiment of the present invention.

[0069] The sheet metal component-based structural parameter optimization design system 100 described in the present invention can be installed in an electronic device. Depending on the functionality implemented, the sheet metal component-based structural parameter optimization design system 100 can include a model building module 101, a region screening module 102, a rotation angle calculation module 103, a curve fitting module 104, and an optimization testing module 105. A module, also referred to as a unit, is a series of computer program segments that can be executed by an electronic device processor and perform a fixed function, and is stored in the electronic device's memory.

[0070] The model building module 101 is used to obtain sheet metal structural parameters input by the user; and build a sheet metal CAD model based on the sheet metal structural parameters; The region screening module 102 is configured to derive the normal vectors and face center coordinates of all facets in the sheet metal part from the sheet metal part CAD model to calculate a normal angle field; and to identify the rib transition region of the sheet metal part based on the normal angle field and a preset angle change threshold. The rotation angle calculation module 103 is used to determine the total transition arc length of any transition rib in the rib position transition area, and calculate the rib rotation angle coefficient at each curvature point of the transition rib based on the curvature point distribution of the transition rib; The curve fitting module 104 is used to perform a step jump analysis on the rib position transition area using the rib rotation coefficient, and perform rib position transition curve fitting on the curvature point of any transition rib based on the analysis result to obtain a rib position transition fitting curve; The optimization test module 105 is used to test the rib position transition area under load cycles using the fitted rib position transition curve to verify the design optimization performance of the rib position transition area.

[0071] In detail, the modules in the sheet metal component-based structural parameter optimization design system 100 according to the embodiment of the present invention are used in the same manner as above. Figure 1 The same technical means are used as the structural parameter optimization design method based on sheet metal parts described in , and can produce the same technical effects, so they will not be repeated here.

[0072] The present invention is therefore intended to be illustrative and non-restrictive in all respects, with the scope of the invention being defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the application documents are intended to be embraced within the present invention.

[0073] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be construed in the widest possible manner consistent with the principles and novel features disclosed herein.

Claims

1. A structural parameter optimization design method based on sheet metal parts, characterized in that: The following steps are involved: Step S1: Obtaining sheet metal structural parameters input by the user; Build sheet metal CAD models based on sheet metal structural parameters; Step S2: deriving the normal vectors and face center coordinates of all facets in the sheet metal part from the sheet metal part CAD model to calculate the normal angle field; determining the rib transition area of ​​the sheet metal part based on the normal angle field and a preset angle change threshold; Step S3: for any transition rib in the rib position transition area, determine the total transition arc length of the transition rib, and calculate the rib rotation coefficient at each curvature point of the transition rib based on the curvature point distribution of the transition rib; Step S4: performing a step jump analysis on the rib position transition area using the rib rotation coefficient, and performing rib position transition curve fitting for any curvature point of the transition rib based on the analysis results to obtain a rib position transition fitting curve; Step S5: Using the fitted rib position transition curve, the rib position transition area is tested under load cycles to verify the design optimization performance of the rib position transition area.

2. The structural parameter optimization design method based on sheet metal parts according to claim 1 is characterized in that: Based on the normal angle field and the preset angle change threshold, the rib transition area of ​​the sheet metal part is confirmed to include: Traverse the normal angle field and mark the faces corresponding to the angles greater than or equal to the preset angle change threshold as transition candidate areas; For the transition candidate area, establish a transition adjacency undirected graph of the adjacent face sets that share edges or vertices with it; Extract the connected domain of the transition adjacency undirected graph to obtain several connected facet clusters, where each facet cluster is a candidate for a spatially continuous angle mutation region; For each connected cluster, the number of facets, total area, maximum angle value, and average angle gradient are calculated, and the transition candidate areas are screened to obtain the rib position transition area of ​​the sheet metal part.

3. The structural parameter optimization design method based on sheet metal parts according to claim 2, characterized in that: Calculating the number of facets, total area, maximum angle value, and average angle gradient, and screening the candidate transition areas also includes: For each connected cluster, extract all face center coordinates and vertex coordinate sets of the face; The longest axis distance in the main direction and the shortest axis distance in the secondary direction of the connected cluster are confirmed by the face-centered coordinates and vertex coordinate sets; According to the preset threshold range, the number of facets, total area, maximum angle value and average angle gradient calculated are used to perform geometric angle distribution screening on the transition candidate area to obtain a first screening area; The aspect ratio of the minimum enclosing rectangle of the connected cluster in three-dimensional space is calculated based on the longest axis distance in the main direction and the shortest axis distance in the secondary direction, and the transition candidate area is geometrically screened by the aspect ratio to obtain the second screening area; The intersection area of ​​the first screening area and the second screening area is screened to obtain the rib position transition area of ​​the sheet metal part.

4. The structural parameter optimization design method based on sheet metal parts according to claim 1 is characterized in that: Step S4 includes the following steps: Step S41: for each rib position transition region, extract the rib rotation coefficient sequence within the region and organize it into discrete angle change data in spatial order; Step S42: Perform step jump detection on the rotation coefficient sequence, identify the position interval where the angle changes suddenly, and mark it as a potential jump segment; Step S43: In each potential jump segment, based on the smooth change trend of the rib position transition area, extract the curvature points representing the transition characteristics and eliminate noise interference; Step S44: For any selected transition rib, a set of control points is collected based on the curvature point, including the first and last ends and the middle key points of the potential jump segment corresponding to the point, and curvature smoothing is performed on each potential jump segment according to the control point set to obtain a smoothed jump curve segment; Step S45: Mapping the smoothed jump curve segment back to the rib position transition region to perform transition curve fitting to obtain a rib position transition fitting curve.

5. The structural parameter optimization design method based on sheet metal parts according to claim 4 is characterized in that: Step S44 includes the following steps: Step S441: For any selected transition rib, extract the curvature key points of the beginning, end, and middle mark of the segment within the range of its potential jump segment, and construct a control point set for the jump segment; Step S442: Arrange the control point set of each jump segment in a logical order and calculate the arc length distance between each point; Step S443: performing local smooth interpolation on the potential jump segment based on the control point set, and performing window filtering on the jump segment area adjacent to the control point during the smoothing process to obtain a smoothed jump curve segment; Step S444: confirming the curve endpoints of the jump curve segment after the primary smoothing, and introducing a curve transition zone according to the arc length distance to obtain the jump curve segment after the secondary smoothing.

6. The structural parameter optimization design method based on sheet metal parts according to claim 5 is characterized in that: For each jump segment control point set, the points are arranged in logical order and include: For each jump segment control point set, the three-dimensional Euclidean distance between adjacent control points is calculated according to the spatial projection order of the control points on the transition rib, and the distance parameter of each control point is accumulated; Normalize the distance parameter to a parameterized coordinate in the interval [0,1] as the position weight of each control point; Each control point in the control point set is sorted in ascending order and checked for proximity based on the position weight. If the distance between any two adjacent control points exceeds a preset threshold, an intermediate compensation point in the interval is inserted to perform a logical order point arrangement.

7. The structural parameter optimization design method based on sheet metal parts according to claim 6, characterized in that: If the distance between any two adjacent control points exceeds a preset threshold, the intermediate compensation points inserted into the interval also include: If the distance between any two adjacent control points exceeds a preset threshold, then for any pair of adjacent control points, the number of intermediate compensation points is determined based on the spatial distance and shape changes of the adjacent control points; Based on the number of intermediate compensation points, the intermediate compensation points are evenly distributed along the curve direction between two adjacent control points; For each intermediate compensation point, the coordinates of the intermediate compensation point in three-dimensional space are calculated by referring to the positions of its adjacent points and the direction of the curve; According to coordinate synchronization, each intermediate compensation point is assigned a curve curvature value consistent with its surrounding adjacent control points, and is sequentially inserted into the jump segment and marked as an intermediate compensation point.

8. The structural parameter optimization design method based on sheet metal parts according to claim 1 is characterized in that: The load cycle setting process includes: constructing a standard loading condition that matches the rib transition area, setting the amplitude, frequency and duration parameters of the load cycle, among which: the amplitude of the load cycle is set to range from 20MPa to 80MPa; the frequency of the load cycle is set to 0.5Hz to 5Hz; the duration parameter setting includes: the single loading time lasts from 5 seconds to 20 seconds, and the total number of cycles is not less than 5000 times or until the critical fatigue state is reached.

9. The structural parameter optimization design method based on sheet metal parts according to claim 8, characterized in that: The rib position transition area is tested under load cycles using the fitted rib position transition curve, including: The rib transition area is tested based on a set load cycle. During the loading process, the strain response data and microcrack growth behavior of the transition area are collected in real time, and key indicators are recorded. These key indicators include: local strain peak, number of cycles in the initial stage of crack growth, and the rate of decrease in structural stiffness under cyclic loading. After completing the preset number of cycles, non-destructive testing is performed on the reinforcement transition area to identify micro-damage or local instability characteristics within the structure. The final accumulated number of cycles and key indicators are judged based on the structural failure judgment criteria to obtain comparative results; the cyclic load resistance of the reinforcement transition area under the optimized design is evaluated, thereby generating load response data and fatigue life prediction reports.

10. A structural parameter optimization design system based on sheet metal parts, characterized in that: For executing the structural parameter optimization design method based on sheet metal parts according to claim 1, the structural parameter optimization design system based on sheet metal parts comprises: The model building module is used to obtain the sheet metal structural parameters input by the user; and build a sheet metal CAD model based on the sheet metal structural parameters; The region screening module is used to derive the normal vectors and face center coordinates of all facets in the sheet metal part from the sheet metal part CAD model to calculate the normal angle field; based on the normal angle field and the preset angle change threshold, the rib transition area of ​​the sheet metal part is determined; The rotation angle calculation module is used to determine the total transition arc length of any transition rib in the rib transition area, and calculate the rib rotation angle coefficient at each curvature point of the transition rib based on the distribution of the curvature points of the transition rib; The curve fitting module is used to perform step jump analysis on the rib position transition area through the rib rotation coefficient, and to fit the rib position transition curve for the curvature point of any transition rib based on the analysis results to obtain the rib position transition fitting curve; The optimization test module is used to use the fitted rib transition curve to test the rib transition area under load cycles to verify the design optimization performance of the rib transition area.

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