Method and system for forming inner panel of interlayer composite structural member

Abstract

The invention provides an interlayer composite material structural member inner panel forming method and system. The forming method comprises the steps that actual three-dimensional data of a formed interlayer composite material structural member inner core special-shaped face are obtained through a three-dimensional scanning method; according to the actual three-dimensional data, an inner panel digital model completely attached to the inner core special-shaped surface is reconstructed through three-dimensional modeling software; according to the inner panel digital model, performing simulation by adopting a material sheet expansion algorithm, and outputting a material sheet expansion graph; slitting the prepreg according to the material sheet expanded drawing to obtain an inner panel material sheet; and the inner panel material piece is laid and attached to the inner core special-shaped face, and real-time shape and position monitoring is carried out in the laying and attaching process. By means of the forming method, the precision and quality of slitting and paving of the material pieces can be remarkably improved, material waste is reduced, and the overall performance and production efficiency of the interlayer composite structural part are improved.

Description

Technical Field

[0001] This invention belongs to the field of composite material molding technology, and more specifically, relates to a method and system for molding the inner panel of a sandwich composite structure. Background Technology

[0002] Composite sandwich structures, with their superior specific strength, specific stiffness, and excellent fatigue and corrosion resistance, have become key components for achieving lightweight and high-performance designs in aerospace, high-end equipment manufacturing, and other fields. These structures typically consist of a low-density inner core and two layers of fiber composite panels bonded together via a co-curing process. The inner panels must precisely fit the irregularly shaped inner core surface designed to meet specific functions; the molding quality directly determines the overall performance and reliability of the component.

[0003] Currently, the inner panel forming of such components generally adopts the traditional process of "hand-laying prepreg - autoclave curing". In this process, because the outer panel surface is usually relatively flat and regular, the sheet unfolding and simulation based on computer-aided design models are relatively accurate and can be directly used to guide cutting and laying. The inner panel usually has irregular and complex shapes, which poses a great challenge to the sheet unfolding software simulation. When dealing with such complex irregular surfaces, the software has difficulty accurately simulating the actual shape, resulting in simulation results that are prone to distortion. This distortion makes the sheet cutting significantly different from the actual surface, making it unsuitable for direct laying.

[0004] Currently, production practices generally employ a trial-and-error manual correction method to modify prepreg sheets. This means repeatedly trying different sheet shapes and sizes until the most suitable solution is found. This method not only consumes a significant amount of manpower and time but also wastes prepreg material. Furthermore, manually modified sheets lack reproducibility and sustainability. Due to the lack of unified standards and methods in the trial-and-error process, each modification is based on specific circumstances, making it impossible to guarantee consistent results across different batches. This fails to meet the high consistency and stability requirements of mass production and cannot ensure product quality and performance. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for forming the inner panel of a sandwich composite structure. This method and system can improve the accuracy of sheet unfolding, reduce the number of times the sheet needs to be modified, reduce labor and time costs and prepreg costs, and improve the forming quality.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a method for forming the inner panel of a sandwich composite structural component, comprising: The actual three-dimensional data of the irregular surface of the inner core of the pre-formed sandwich composite structural component was obtained by using a three-dimensional scanning method. Based on the actual three-dimensional data, a digital model of the inner panel that fits the irregular surface of the inner core is reconstructed using three-dimensional modeling software. Based on the digital model of the inner panel, a material unfolding algorithm is used for simulation, and the unfolded material diagram is output. According to the unfolded diagram of the prepreg, the prepreg is cut to obtain the inner panel sheet; The inner panel sheet is laid onto the irregular surface of the inner core, and the shape and position are monitored in real time during the laying process.

[0007] In one embodiment, the actual three-dimensional data of the inner core irregular surface of the formed sandwich composite structure is obtained by using a three-dimensional scanning method, and a blue light three-dimensional scanning system is used for scanning.

[0008] In one embodiment, the blue light 3D scanning system uses a blue LED array with a wavelength of 440-460nm as a light source, and the blue light 3D scanning system uses a high-resolution CCD camera to acquire images.

[0009] In one embodiment, based on the actual three-dimensional data, the digital model of the inner panel that fits the irregular surface of the inner core is reconstructed using three-dimensional modeling software. The reconstruction of the digital model of the inner panel is carried out using a non-uniform rational B-spline modeling method, and the first derivative or second derivative between adjacent surface patches is ensured to be continuous.

[0010] In one embodiment, based on the digital model of the inner panel, a sheet unfolding algorithm is used for simulation, and the unfolded sheet diagram is output, including: Adjust the mesh accuracy during the sheet unfolding simulation process; Anisotropic mechanical parameters of fiber composite materials are introduced into the simulation, and the mechanical parameters include at least the elastic modulus and Poisson's ratio; Geometric compensation is performed on the shape of the unfolded sheet based on the material's stress-strain curve and bending radius.

[0011] In one embodiment, before cutting the prepreg according to the unfolded sheet diagram to obtain the inner panel sheet, the method further includes: planning a cutting area on the digital model of the inner panel to divide the inner panel into multiple sub-regions; and performing unfolding simulation on each of the sub-regions using a sheet unfolding algorithm to obtain the unfolded sheet diagrams and dimensions of multiple sub-sheets.

[0012] In one embodiment, the prepreg is cut according to the unfolded diagram of the sheet to obtain the inner panel sheet. The cutting is carried out using a cutting device, and the cutting size error is controlled within ±0.1mm. The cutting speed is controlled at 50-500mm / s, and the cutting pressure is controlled at 0.1-1MPa.

[0013] In one embodiment, the inner panel sheet is laid onto the inner core irregular surface, and real-time shape and position monitoring is performed during the laying process. The real-time shape and position monitoring adopts optical measurement and laser tracking technology. When the deviation between the sheet and the theoretical surface is detected to exceed a set threshold, the laying is paused and adjustments are made.

[0014] In one embodiment, the set threshold is ±2mm.

[0015] A second aspect of the present invention provides a molding system for an inner panel of a sandwich composite structure, used to perform the molding method for an inner panel of a sandwich composite structure as described above, the molding system comprising: The data acquisition module includes a 3D scanning device, used to acquire the actual 3D point cloud data of the inner core irregular surface; The data processing and modeling module includes a computer equipped with 3D modeling software, used to process point cloud data and reconstruct the digital model of the inner panel. The sheet design and simulation module is used to run the sheet unfolding algorithm and output the unfolded sheet diagram; An automated cutting device is used to cut the prepreg according to the unfolded diagram of the material sheet; The tiling and monitoring module includes a tiling workbench and optical measurement and laser tracking equipment for real-time monitoring of the tiling process.

[0016] The method for forming the inner panel of a sandwich composite structure provided by the present invention includes: acquiring actual three-dimensional data of the irregular surface of the inner core of the formed sandwich composite structure using a three-dimensional scanning method; reconstructing a digital model of the inner panel that fits with the irregular surface of the inner core using three-dimensional modeling software based on the actual three-dimensional data; performing simulation using a sheet unfolding algorithm based on the digital model of the inner panel and outputting a sheet unfolding diagram; cutting the prepreg according to the sheet unfolding diagram to obtain inner panel sheets; and laying the inner panel sheets onto the irregular surface of the inner core, while performing real-time shape and position monitoring during the laying process. This method for forming the inner panel of sandwich composite structural components directly obtains data from actual workpieces, eliminating the initial errors caused by the inconsistency between theoretical models and physical objects in traditional methods. By simulating material properties, it predicts and solves problems such as wrinkling and gaps that may occur during installation. It transforms the trial-and-error process that relies on personal experience into a standardized process based on data, ensuring high consistency and quality stability of different batches of products. This meets the prerequisite for mass production, significantly reduces repeated modifications, material waste, and time losses caused by inaccurate material sheets, and effectively improves production efficiency and economic benefits. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of the method for forming the inner panel of a sandwich composite structure provided in an embodiment of the present invention; Figure 2 This is a bottom view of a sandwich composite structure provided in an embodiment of the present invention; Figure 3 This is an isometric view of a sandwich composite structure provided in an embodiment of the present invention; Figure 4 The image shows a right view of a sandwich composite structure provided in an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms “comprising” and “having” as used herein, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0021] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. It should be understood that the term "and / or" as used herein is merely a description of the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A alone, A and B simultaneously, and B alone. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] Currently, sandwich structure components are formed by manually laying fiber prepreg followed by autoclave curing. While laying the outer panel, due to its relatively flat surface, allows for high accuracy in unfolding and cutting a single sheet, laying the inner panel (the upper panel of the sandwich core) is challenging due to its complex irregular surface. Simulating the unfolding process using sheet unfolding software is difficult and prone to distortion, resulting in significant discrepancies between the sheet cut and the actual surface. Laying the inner panel requires repeated trial-and-error modifications, incurring substantial manpower, time, and prepreg costs. Furthermore, relying on experience and simple manual calculations leads to errors in cutting dimensions, making it difficult to meet high-precision requirements. Manually modified sheets lack reproducibility and sustainability, making them unsuitable for mass production. To address these issues, this invention proposes a method and system for forming the inner panel of sandwich composite structure components, improving simulation accuracy and cutting precision. This solves the problems of distorted unfolding and inaccurate cutting of inner panel sheets in existing technologies, as well as unsuitability for mass production, thereby improving production efficiency and product quality.

[0024] The method and system for forming the inner panel of the sandwich composite structure provided by the present invention will be described in detail below with reference to specific embodiments.

[0025] Figure 1 This is a flowchart of the method for forming the inner panel of a sandwich composite structure according to an embodiment of the present invention. Figure 2 This is a bottom view of a sandwich composite structure provided in an embodiment of the present invention. Figure 3 This is an isometric view of a sandwich composite structure provided in an embodiment of the present invention. Figure 4 This is a right view of the sandwich composite structure provided in an embodiment of the present invention. Please refer to [link / reference]. Figures 1-4 The first aspect of this embodiment provides a method for forming the inner panel of a sandwich composite structure, including the following steps: S101. Use a 3D scanning method to obtain the actual 3D data of the irregular surface of the inner core of the pre-formed sandwich composite structural component; Specifically, this step occurs after the outer panel 1 and inner core 2 of the sandwich structure have been laid and pre-cured. At this point, the irregular surface of the inner core 2 has been formed. Using a non-contact 3D scanner, the exposed irregular surface of the inner core 2 is scanned from all angles to obtain high-density point cloud data characterizing its true geometry. 3D scanning technology can quickly and accurately acquire the shape information of the irregular surface, providing basic data for subsequent modeling and sheet unfolding.

[0026] S102. Based on the actual three-dimensional data, reconstruct the digital model of the inner panel that fits the irregular surface of the inner core using three-dimensional modeling software; Specifically, the actual 3D data obtained in the previous step is imported into professional 3D modeling software (such as CATIA, Geomagic, etc.). The software uses this point cloud data as constraints and benchmarks, and through surface fitting or reverse engineering functions, constructs a closed digital surface model of the inner panel 3 that fits the irregular surface of the inner core 2 in 3D space. S103. Based on the digital model of the inner panel, a sheet unfolding algorithm is used for simulation, and the unfolded sheet diagram is output. Specifically, using the high-precision digital model of the inner panel 3 generated in the previous step as input, the sheet unfolding simulation module is started. This module uses algorithms based on the finite element method or geometric unfolding theory to "flatten" the three-dimensional, complex NURBS surface model into one or more two-dimensional planar graphics, i.e., the sheet unfolding diagram. This process simulates the physical process of prepreg deforming from a planar state and bonding to an irregular surface in a virtual environment.

[0027] S104. According to the unfolded diagram of the prepreg, the prepreg is cut to obtain the inner panel sheet; Specifically, the simulation output of the prepreg unfolded diagram (usually in DXF or IGES format) is imported into the control system of a CNC cutting machine (such as a vibrating knife, ultrasonic knife, or laser cutting machine). Based on the graphic data, the cutting machine automatically cuts the prepreg roll or large-format sheet to obtain an inner panel 3 sheet that perfectly matches the design shape.

[0028] S105. Lay the inner panel sheet onto the inner core irregular surface and monitor its shape and position in real time during the laying process.

[0029] Specifically, operators or automated installation equipment lay the slit sheets onto the corresponding irregular surface of the inner core 2. During this process, an optical photogrammetry system or laser tracker integrated into the installation station continuously measures the three-dimensional coordinates of key feature points of the sheet and compares them with the theoretical model in real time.

[0030] The molding method for the inner panel 3 of the sandwich composite structure in this embodiment starts from the existing real inner core 2, creates its digital model through 3D scanning, performs precise modeling and physical simulation on this digital model in the digital world, predicts and optimizes the molding process, and generates the optimal unfolded diagram. The optimized unfolded diagram is used to guide physical production (cutting and laying), and the consistency between the physical execution process and the digital plan is ensured through real-time monitoring.

[0031] The forming method of the inner panel 3 of the sandwich composite structure in this embodiment includes the following steps: obtaining the actual three-dimensional data of the irregular surface of the inner core 2 of the formed sandwich composite structure using a three-dimensional scanning method; reconstructing the digital model of the inner panel 3 that fits with the irregular surface of the inner core 2 using three-dimensional modeling software based on the actual three-dimensional data; performing simulation using a sheet unfolding algorithm based on the digital model of the inner panel 3 and outputting a sheet unfolding diagram; cutting the prepreg according to the sheet unfolding diagram to obtain the inner panel 3 sheet; laying the inner panel 3 sheet onto the irregular surface of the inner core 2 and performing real-time shape and position monitoring during the laying process. This method directly obtains data from actual workpieces, eliminating the initial errors caused by the inconsistency between the CAD theoretical model and the actual object in traditional methods. By simulating material properties, it predicts and solves problems such as wrinkling and gaps that may occur during installation. It transforms the trial-and-error process that relies on personal experience into a standardized process based on data, ensuring high consistency and quality stability of different batches of products. This lays the foundation for mass production, significantly reducing repeated modifications, material waste, and time losses caused by inaccurate material pieces, and effectively improving production efficiency and economic benefits.

[0032] Furthermore, in acquiring the actual three-dimensional data of the irregular surface of the inner core 2 of the formed sandwich composite structure using a three-dimensional scanning method, a blue light three-dimensional scanning system is used for scanning. Preferably, the blue light three-dimensional scanning system uses a blue LED array with a wavelength of 440-460nm as the light source, and the blue light three-dimensional scanning system uses a high-resolution CCD camera to acquire images.

[0033] Specifically, this embodiment employs a high-power blue LED array with a wavelength of 450nm and an average radiant power of 0.5mW. The LED array is distributed around the scanning head to form a uniform blue light illumination field. The selection of the blue light wavelength is based on the optical characteristics of the materials of the inner core 2 and outer panel 1 of the sandwich composite structure. This wavelength of blue light can produce the best reflection effect on the material surface, reducing light scattering and absorption, and improving scanning accuracy. This embodiment uses a high-sensitivity CCD camera with high-resolution pixels, which can ensure the acquisition of clear, high-resolution images at a certain working distance. The camera arrangement in this embodiment adopts a multi-angle, multi-directional approach to ensure full coverage of the irregular surface of the inner core 2. The corresponding scanning speed is set according to the complexity of the irregular surface of the inner core 2 and the material characteristics. For example, for relatively flat and simple areas, the scanning speed can be appropriately increased, but it cannot exceed the maximum scanning speed. For complex irregular surfaces, such as areas with large curvature changes and sharp edges, the scanning speed should be reduced to the minimum scanning speed, because excessively fast scanning speed will lead to image blurring and loss of measurement points.

[0034] This embodiment uses a blue light 3D scanning system, further specifying the light source as a blue LED array with a wavelength of 440-460nm, and the image sensor as a high-resolution CCD camera. Blue light has a shorter wavelength than traditional white light or lasers, resulting in finer light spots when scanning composite materials with indistinct surface textures, and is less affected by ambient light interference, thus obtaining higher precision and higher resolution point cloud data. The high-resolution CCD camera ensures sufficient detail is captured. This configuration significantly improves the scanning accuracy and point cloud quality of the core 2 with subtle features or smooth surfaces, providing an optimal data foundation for subsequent high-precision modeling.

[0035] Furthermore, in the process of reconstructing the digital model of the inner panel 3 that fits the irregular surface of the inner core 2 using 3D modeling software based on the actual 3D data, the non-uniform rational B-spline (NURBS) modeling method is used to reconstruct the digital model of the inner panel 3, and to ensure that the first derivative or the second derivative is continuous between adjacent surface patches.

[0036] Specifically, based on the imported 3D data and the created benchmark, the initial modeling of the inner panel 3 begins. Using the software's surface generation tool, the approximate surface shape of the inner panel 3 is generated according to the point cloud data and topology of the irregular surface of the inner core 2. When the irregular surface of the inner core 2 has complex curvature changes, the NURBS surface modeling method is adopted. For irregular surfaces with multiple local features, they are divided into several sub-regions for separate modeling, and then the sub-surfaces are merged into a complete inner panel surface through Boolean operations and other methods. During this process, the first derivative continuity (G1 continuity, i.e., tangent continuity) or second derivative continuity (G2 continuity, i.e., curvature continuity) between adjacent surface patches is ensured to guarantee the smoothness of the inner panel 3 surface.

[0037] After the initial modeling in this embodiment is completed, the fit between the inner panel 3 and the irregular surface of the inner core 2 is checked using software analysis tools (such as Distance Analysis in Catia). The distance deviation between them is calculated, and for areas with a distance deviation exceeding 0.75mm, local adjustments are made. The curved surface of the inner panel 3 is fine-tuned using the software's deformation tools, such as stretching, twisting, and scaling. Simultaneously, the irregular surface of the inner core 2 can be displayed semi-transparently for a more intuitive observation of the fit. During the adjustment process, the quality parameters of the curved surface of the inner panel 3, such as Gaussian curvature and average curvature, are checked to ensure that the adjusted surface still meets the design requirements. If the irregular surface of the inner core 2 has specific functional areas (such as mounting holes, reinforcing ribs, etc.), the accurate matching of the inner panel 3 at these locations must be ensured.

[0038] This embodiment explicitly adopts the NURBS (Non-Uniform Rational B-Spline) surface modeling method. Adjacent surface patches satisfy G1 or G2 continuity. NURBS is an industry-standard surface representation method that can accurately describe complex freeform surfaces. G1 and G2 continuity means that the surface transitions smoothly at the connection point without sharp creases or curvature abrupt changes. This embodiment ensures that the reconstructed digital model is not only accurate but also smooth. The smooth model in this embodiment is crucial for subsequent sheet unfolding simulation, which can avoid simulation calculation divergence or unrealistic stress concentration caused by mathematical flaws in the model itself (such as sharp edges), thereby improving the reliability and manufacturability of the unfolding results.

[0039] Preferably, the step of simulating the unfolding algorithm based on the digital model of the inner panel 3 and outputting the unfolded sheet diagram includes: adjusting the grid accuracy during the unfolding simulation process; Specifically, increasing the mesh resolution allows the simulation model to more closely approximate the actual structure, thus more accurately reflecting the complexity of the surface. This embodiment allows for the gradual increase of mesh density, observation of changes in the fitting effect, and finding a suitable mesh accuracy. Anisotropic mechanical parameters of fiber composite materials are introduced into the simulation, including at least the elastic modulus and Poisson's ratio. Specifically, this embodiment takes into account the characteristics of fiber composite materials, such as fiber orientation and strength, to ensure the mechanical properties of the inner panel 3. For example, this embodiment carefully examines and corrects the mechanical property parameters of the composite material, such as elastic modulus and Poisson's ratio, to ensure that these parameters accurately reflect the characteristics of the actual material, thereby improving the accuracy of the simulation.

[0040] Geometric compensation is performed on the shape of the unfolded sheet based on the material's stress-strain curve and bending radius.

[0041] Specifically, the software's unfolding function is used to unfold the inner panel 3 surface into a planar shape. During the unfolding process, the physical properties of the material, such as thickness and ductility, must be considered. Based on factors such as the material's stress-strain curve and bending radius, the shape of the unfolded sheet is optimized. The unfolded sheet is checked for issues such as self-intersection and excessive stretching. If the maximum stretching rate of the sheet exceeds the allowable stretching rate, the modeling of the inner panel 3 needs to be readjusted or a suitable material needs to be selected. Simultaneously, necessary process allowances, such as cutting allowances and bending allowances, are added to the sheet during the unfolding process to meet the requirements of subsequent processing techniques.

[0042] This embodiment proposes three specific optimization measures for the material sheet unfolding simulation process: ① adjusting mesh accuracy; ② introducing anisotropic material parameters; ③ performing geometric compensation based on material physical properties. In the simulation software, the model is divided into finite element meshes, with local refinement applied to areas with high curvature to ensure the capture of complex deformations. In the material property library, elastic modulus, Poisson's ratio, and shear modulus are set for the prepreg in different fiber directions, such as 0° and 90°, to ensure its mechanical behavior is consistent with real materials. After initial unfolding, the simulation algorithm calculates the strain in each region of the material sheet. For regions predicted to be overstretched, the algorithm automatically enlarges the size of the corresponding region in the unfolded diagram; for regions predicted to accumulate and wrinkle, it automatically reduces the size. The final unfolded diagram obtained in this embodiment is a "smart drawing" that has pre-compensated for material deformation. The material sheets cut from this drawing can naturally and conformably adapt to irregular surfaces during actual installation, greatly improving the success rate of the first installation.

[0043] Furthermore, before cutting the prepreg according to the unfolded diagram to obtain the inner panel sheet, the method further includes: planning a cutting area on the digital model of the inner panel 3 to divide the inner panel 3 into multiple sub-regions; Specifically, based on the data from precise modeling, the material sheet is virtually slit and simulated in 3D modeling software. During the simulation, factors such as the parameter characteristics of the cutting equipment, the material properties of the prepreg, the mechanical performance requirements of the structural components, shape characteristics, and the difficulty of the laying process are fully considered. The inner panel 3 of the structural component is analyzed and planned to ensure the operability and accuracy of each area in the subsequent laying process, and to make the connection between areas more reasonable, thereby optimizing the overall structure. While meeting the strength requirements of the structural component, the inner panel 3 is divided into several smaller areas. The division of these smaller areas is determined based on the shape, size, and laying process requirements of the inner panel 3, aiming to reduce the complexity of each area to facilitate subsequent laying operations. For example, the inner panel 3 is slit along the prepreg angle. If the layup angle is 45°, the slit direction must also follow 45° to avoid breaking the fibers. Considering strength, the size of the slit sheet is not less than 0.1 square meters.

[0044] The unfolding algorithm is used to perform unfolding simulation on each of the sub-regions to obtain multiple unfolded diagrams and dimensions of the sub-sheets.

[0045] Specifically, the slit pieces are simulated in 3D modeling software using a specific unfolding algorithm to obtain the shape and size data of the unfolded pieces, and the unfolded pieces are numbered and marked.

[0046] Furthermore, in the process of cutting the prepreg according to the unfolded diagram of the sheet to obtain the inner panel sheet, the cutting is carried out using a cutting device, the cutting size error is controlled within ±0.1mm, the cutting speed is controlled within 50-500mm / s, and the cutting pressure is controlled within 0.1-1MPa.

[0047] Specifically, the unfolded material sheet data is transmitted to the control system of the material sheet cutting process, driving the cutting equipment to perform the actual slitting operation on the prepreg. During the slitting process, a high-precision cutting device is used, which operates according to preset parameters and has precise positioning and size control functions, enabling the size error of the material sheet to be controlled within ±0.1mm, preferably ±0.05mm. In this embodiment, the cutting speed, cutting pressure, and other parameters are precisely set according to the type of prepreg (such as carbon fiber prepreg, glass fiber prepreg, etc.) and thickness. The cutting speed is generally controlled between 50-500mm / s, and the cutting pressure is adjusted between 0.1MPa-1MPa according to the thickness of the prepreg to avoid damage to the prepreg such as tearing, delamination, and fiber breakage during slitting, ensuring the integrity and performance of the material sheet are not compromised.

[0048] Furthermore, the inner panel 3 sheet is laid onto the irregular surface of the inner core 2, and real-time position monitoring is performed during the laying process. The real-time position monitoring adopts optical measurement and laser tracking technology. When the deviation between the sheet and the theoretical surface exceeds a set threshold, the laying is paused and adjustments are made. Preferably, the set threshold is ±2mm.

[0049] Specifically, according to the pre-planned area and laying sequence, the slits and unfolded sheets are laid one by one onto the sandwich panel. During the laying process, advanced technologies such as optical measurement and laser tracking are used to monitor the process in real time. The optical measurement system emits a specific light beam and receives reflected light signals to accurately acquire information such as the position, shape, and relative height of the sheet to the ideal surface. The laser tracking system tracks and records the movement trajectory of the sheet with high precision. Once a deviation between the sheet and the surface is detected, such as a deviation exceeding ±2mm, the manual laying operation is immediately suspended. The ±2mm threshold in this embodiment is a typical value set based on the general accuracy requirements of composite material laying processes, ensuring both quality and practical engineering operability. This embodiment uses the deviation data fed back by the monitoring system to manually adjust the position of the sheet. After adjustment, the laying process continues, thereby effectively improving the accuracy of laying and reducing the scrap rate caused by accumulated deviations, while also improving the overall efficiency of manual laying to a certain extent. In this embodiment, key parameters such as vacuum bag pre-extraction pressure and pre-extraction time are controlled during the laying process. For example, based on the core material (such as honeycomb core material, foam core material, etc.) used in the sandwich composite structure, the type of prepreg (such as carbon fiber prepreg, glass fiber prepreg, etc.), and the design thickness and dimensions of the panel, the optimal vacuum bag pre-extraction pressure range and pre-extraction time interval are determined through extensive experiments and theoretical analysis. For instance, for a specific carbon fiber prepreg and sandwich structure, the pre-extraction pressure is controlled between -20 kPa and -80 kPa, and the pre-extraction time is set to 10 to 20 minutes. This ensures that the inner panel 3 and the inner core 2 can form a good and stable bond strength during the installation process, avoiding weak bonding due to insufficient pressure or material damage due to excessive pressure.

[0050] The method for forming the inner panel of sandwich composite structural components in this embodiment can significantly improve the accuracy and quality of sheet cutting and laying, reduce material waste, and enhance the overall performance and production efficiency of composite structural components. It is applicable to the manufacturing needs of high-performance composite structural components in multiple fields such as aerospace, automobile manufacturing, and high-end equipment manufacturing.

[0051] The method for forming the inner panel of the sandwich composite structure in this invention directly obtains data from the actual workpiece, eliminating the initial error caused by the inconsistency between the theoretical model and the actual object in traditional methods. By simulating the material properties, it predicts and solves problems such as wrinkling and gaps that may occur during installation. It transforms the trial-and-error process that relies on personal experience into a standardized process based on data, ensuring high consistency and quality stability of different batches of products, meeting the prerequisite for mass production, and significantly reducing repeated modifications, material waste, and time loss caused by inaccurate material sheets, effectively improving production efficiency and economic benefits.

[0052] The second aspect of this embodiment provides a molding system for the inner panel of a sandwich composite structure, used to execute the molding method for the inner panel of a sandwich composite structure as described in the above embodiment. The molding system includes a data acquisition module, a data processing and modeling module, a sheet design and simulation module, an automated cutting device, and a laying and monitoring module. The data acquisition module includes a 3D scanning device used to acquire actual 3D point cloud data of the irregular surface of the inner core. The data processing and modeling module includes a computer installed with 3D modeling software. The computer is used to process the point cloud data and reconstruct the digital model of the inner panel. The sheet design and simulation module is used to run a sheet unfolding algorithm and output a sheet unfolding diagram. The automated cutting device is used to cut the prepreg according to the sheet unfolding diagram. The laying and monitoring module includes a laying workbench and an optical measurement and laser tracking device for real-time monitoring of the laying process.

[0053] The molding system in this embodiment seamlessly integrates five key stages: data acquisition, computer modeling, simulation design, automatic material feeding, and laying monitoring. These stages are achieved through a data acquisition module, a data processing and modeling module, a sheet design and simulation module, automated cutting equipment, and a laying and monitoring module. This transforms a discrete process reliant on manual experience into a standardized, controllable digital workflow. At the hardware level, this fundamentally solves the problems of large fluctuations in molding quality, significant material waste, and the inability to meet the requirements of consistent mass production caused by the complex shape of the inner panel. This improves the production quality and efficiency of sandwich composite structural components.

[0054] In the above description, the terms "an embodiment," "some embodiments," "example," "specific example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples. The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for forming the inner panel of a sandwich composite structural component, characterized in that, Includes the following steps: The actual three-dimensional data of the irregular surface of the inner core of the pre-formed sandwich composite structural component was obtained by using a three-dimensional scanning method. Based on the actual three-dimensional data, a digital model of the inner panel that fits the irregular surface of the inner core is reconstructed using three-dimensional modeling software. Based on the digital model of the inner panel, a material unfolding algorithm is used for simulation, and the unfolded material diagram is output. According to the unfolded diagram of the prepreg, the prepreg is cut to obtain the inner panel sheet; The inner panel sheet is laid onto the irregular surface of the inner core, and the shape and position are monitored in real time during the laying process.

2. The method for forming the inner panel of a sandwich composite structure according to claim 1, characterized in that: In the process of obtaining the actual three-dimensional data of the inner core irregular surface of the pre-formed sandwich composite structural component using a three-dimensional scanning method, a blue light three-dimensional scanning system is used for scanning.

3. The method for forming the inner panel of a sandwich composite structure according to claim 2, characterized in that: The blue light 3D scanning system uses a blue LED array with a wavelength of 440-460nm as the light source and a high-resolution CCD camera to acquire images.

4. The method for forming the inner panel of a sandwich composite structure according to claim 1, characterized in that... Based on the actual three-dimensional data, the digital model of the inner panel that fits the irregular surface of the inner core is reconstructed using three-dimensional modeling software. The non-uniform rational B-spline modeling method is used to reconstruct the digital model of the inner panel, and the first derivative or second derivative is continuous between adjacent surface patches.

5. The method for forming the inner panel of a sandwich composite structure according to claim 1, characterized in that: Based on the digital model of the inner panel, a sheet unfolding algorithm is used for simulation, and the unfolded sheet diagram is output, including: Adjust the mesh accuracy during the sheet unfolding simulation process; Anisotropic mechanical parameters of fiber composite materials are introduced into the simulation, and the mechanical parameters include at least the elastic modulus and Poisson's ratio; Geometric compensation is performed on the shape of the unfolded sheet based on the material's stress-strain curve and bending radius.

6. The method for forming the inner panel of a sandwich composite structure according to claim 1 or 5, characterized in that: Before cutting the prepreg according to the unfolded diagram to obtain the inner panel sheet, the process further includes: Plan and divide the inner panel into multiple sub-regions on the digital model of the inner panel; The unfolding algorithm is used to perform unfolding simulation on each of the sub-regions to obtain multiple unfolded diagrams and dimensions of the sub-sheets.

7. The method for forming the inner panel of a sandwich composite structure according to claim 6, characterized in that: According to the unfolded diagram of the material sheet, the prepreg is cut to obtain the inner panel material sheet. The cutting is carried out by a cutting device, and the cutting size error is controlled within ±0.1mm. The cutting speed is controlled at 50-500mm / s, and the cutting pressure is controlled at 0.1-1MPa.

8. The method for forming the inner panel of a sandwich composite structure according to claim 1, characterized in that: The inner panel sheet is laid onto the irregular surface of the inner core, and real-time shape and position monitoring is performed during the laying process. The real-time shape and position monitoring adopts optical measurement and laser tracking technology. When the deviation between the sheet and the theoretical surface exceeds the set threshold, the laying is paused and adjustments are made.

9. The method for forming the inner panel of a sandwich composite structure according to claim 8, characterized in that: The set threshold is ±2mm.

10. A forming system for an inner panel of a sandwich composite structure, used to perform the forming method for an inner panel of a sandwich composite structure as described in any one of claims 1-9, characterized in that, The molding system includes: The data acquisition module includes a 3D scanning device, used to acquire the actual 3D point cloud data of the inner core irregular surface; The data processing and modeling module includes a computer equipped with 3D modeling software, used to process point cloud data and reconstruct the digital model of the inner panel. The sheet design and simulation module is used to run the sheet unfolding algorithm and output the unfolded sheet diagram; An automated cutting device is used to cut the prepreg according to the unfolded diagram of the material sheet; The tiling and monitoring module includes a tiling workbench and optical measurement and laser tracking equipment for real-time monitoring of the tiling process.

Images