A method and device for tracking the evolution of the ablation topography interface of a composite material

Abstract

The present disclosure provides a composite material ablation morphology interface evolution tracking method and device. The method comprises the following steps: initialization step, ablation rate calculation step, grid point coordinate calculation step, morphology reconstruction step, burning tip determination step, reinforcement grid updating step, and evolution tracking and output step. The present disclosure proposes an evolution tracking method of composite material ablation morphology interface based on Lagrange method, which combines the ablation recession of virtual top surface and the determination strategy of reinforcement burning tip, greatly reduces the determination and reconstruction difficulty of non-physical distortion in the evolution process of interface grid, solves the grid distortion and distortion problem that may occur under the condition of ablation deformation, has the characteristics of high accuracy of morphology interface tracking and easy implementation of simulation tracking strategy, and the overall grid calculation amount of the scheme is small, so that the calculation efficiency is improved.

Description

Technical Field

[0001] This disclosure relates to the field of aircraft thermal protection design and evaluation technology, and in particular to a method, apparatus, storage medium and electronic device for tracking the evolution of composite material ablation morphology interfaces. Background Technology

[0002] In thermal boundary environments such as aerodynamic heating, material surfaces exhibit varying degrees of ablation. The accuracy of ablation shape evolution simulation is crucial for simulating material thermal response and evaluating thermal performance. Ablation shape evolution simulation falls under the category of tracking complex moving interfaces. Simulation methods applicable to this type of problem include the Eulerian method and the Lagrangian method. The Eulerian method generally requires a sufficiently fine mesh in the computational domain during the tracking of the ablated surface, thus requiring a relatively large computational load. The Lagrangian method, on the other hand, calculates the normal velocity of each mesh point on the ablated surface and generates new mesh points. At a new time point, it regenerates the ablated surface using all newly generated mesh points, requiring a relatively smaller mesh size. However, it needs to address mesh distortion and non-physical distortion issues that may arise due to interface mesh evolution.

[0003] Because the Lagrangian method generally requires the development of targeted mesh distortion and reconstruction strategies when dealing with mesh distortion and non-physical mesh distortion problems that may occur during interface mesh evolution, and the development is quite difficult, most current composite ablation morphology interface evolution tracking methods adopt the Eulerian method. These methods include the VOF (Volume of Fluid) method and the Level Set method, but these methods often require sufficiently fine mesh division of the computational domain, and the computational load is often very large when facing large deformation ablation problems, resulting in relatively low overall computational efficiency. Summary of the Invention

[0004] The purpose of this disclosure is to provide a method, apparatus, storage medium, and electronic device for tracking the evolution of ablation morphology interfaces of composite materials, so as to solve the above-mentioned problems existing in the prior art.

[0005] The embodiments of this disclosure adopt the following technical solution: an evolution tracking method for the ablation morphology interface of composite materials, comprising:

[0006] The initialization steps include at least: constructing a physical model of the composite material, and based on the size of the physical model, using two two-dimensional surface meshes to characterize the ablation plane of the matrix and the outer contour surface of the reinforcement, and setting a virtual top surface to describe the theoretical ablation position of the top of the reinforcement;

[0007] The ablation rate calculation step includes at least: calculating the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface based on the surface thermal environment parameters of the composite material.

[0008] The grid point coordinate calculation steps include at least: determining the ablation direction of each grid point, and determining the spatial coordinates of each grid point at the current time step in combination with the ablation rate of the grid point;

[0009] The topography reconstruction step includes at least: performing non-physical distortion network mesh reconstruction on the first topography interface formed by the spatial coordinates of all the grid points, and determining the reconstructed coordinates of each grid point after reconstruction to form a second topography interface;

[0010] The ablation determination step includes at least the following steps: updating the position of the virtual top surface at the current time step according to the ablation rate of the virtual top surface, determining the coordinates of the virtual top surface according to the reconstructed coordinates of all the grid points, determining the current area of ​​the virtual top surface according to the coordinates of the virtual top surface, and determining the ablation of the reinforcement if the current area is less than α times the original area of ​​the virtual top surface; otherwise, determining that the reinforcement is not ablated.

[0011] The augmentation mesh update step includes at least the following steps: if it is determined that the augmentation is not tipped, the virtual top surface is used as the actual top surface of the augmentation, and the updated coordinates of each mesh point in the actual top surface are determined according to the coordinates of the virtual top surface, and an interface topography network mesh is formed at the current time step; if it is determined that the augmentation is tipped, the actual height of the augmentation at the current time step is determined, and the reconstructed coordinates of all mesh points exceeding the actual height are deleted, so as to form an interface topography network mesh.

[0012] The evolution tracking and output steps include at least: detecting whether the evolution end time has been reached; if the evolution end time has not been reached, updating the time step and surface thermal environment parameters, and re-executing the ablation rate calculation step; if the evolution end time has been reached, outputting the interface morphology network mesh at each time step, and obtaining the evolution tracking results of the composite material ablation morphology interface.

[0013] This disclosure also provides an evolution tracking device for the ablation morphology interface of composite materials, including:

[0014] An initialization module is used to construct a physical model of the composite material, and based on the size of the physical model, two two-dimensional surface meshes are used to characterize the ablation plane of the matrix and the outer contour surface of the reinforcement, and a virtual top surface is set to describe the theoretical ablation position of the top of the reinforcement.

[0015] The ablation rate calculation module is used to calculate the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface based on the surface thermal environment parameters of the composite material.

[0016] The grid point coordinate calculation module is used to determine the ablation direction of each grid point and, in combination with the ablation rate of the grid point, determine the spatial coordinates of each grid point at the current time step.

[0017] The topography reconstruction module is used to perform non-physical distortion network mesh reconstruction on the first topography interface formed by the spatial coordinates of all the grid points, and to determine the reconstruction coordinates of each grid point after reconstruction, thus forming a second topography interface.

[0018] The ablation determination module is used to update the position of the virtual top surface at the current time step according to the ablation rate of the virtual top surface, determine the coordinates of the virtual top surface according to the reconstructed coordinates of all the grid points, and determine the current area of ​​the virtual top surface according to the coordinates of the virtual top surface. If the current area is less than α times the original area of ​​the virtual top surface, the reinforcement is determined to be ablated; otherwise, the reinforcement is determined not to be ablated.

[0019] The augmentation mesh update module is used to, when it is determined that the augmentation is not sharpened, use the virtual top surface as the actual top surface of the augmentation, and determine the updated coordinates of each mesh point in the actual top surface according to the coordinates of the virtual top surface, and form the interface topography mesh at the current time step; when it is determined that the augmentation is sharpened, determine the actual height of the augmentation at the current time step, and delete the reconstructed coordinates of all mesh points that exceed the actual height, so as to form the interface topography mesh.

[0020] The evolution tracking and output module is used to detect whether the evolution end time has been reached. If the evolution end time has not been reached, the time step and surface thermal environment parameters are updated, and the ablation rate calculation module is called again. If the evolution end time has been reached, the interface morphology network mesh at each time step is output to obtain the evolution tracking results of the composite material ablation morphology interface.

[0021] This disclosure also provides a storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described method for tracking the evolution of ablation morphology interfaces of composite materials.

[0022] This disclosure also provides an electronic device, including at least a memory and a processor. The memory stores a computer program, and the processor, when executing the computer program in the memory, implements the steps of the above-described method for tracking the evolution of ablation morphology interfaces of composite materials.

[0023] The beneficial effects of this disclosure are as follows: It proposes an evolution tracking method for the ablation morphology interface of composite materials based on the Lagrange method. By combining the ablation regression of the virtual top surface and the strategy of determining the ablation tip of the reinforcement, it significantly reduces the difficulty of determining and reconstructing non-physical distortions during the interface mesh evolution process. It solves the mesh distortion and deformation problems that may occur under ablation deformation. It has the characteristics of high accuracy in morphology interface tracking and easy implementation of simulation tracking strategy. At the same time, the overall mesh calculation volume of the scheme is small, which improves the computational efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, 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 recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the method for tracking the evolution of the ablation morphology interface of composite materials in the first embodiment of this disclosure;

[0026] Figure 2 This is a schematic diagram of the mesh division result in the first embodiment of this disclosure;

[0027] Figure 3 This is a schematic diagram showing the position of the virtual top surface in the first embodiment of this disclosure when it is not sharpened;

[0028] Figure 4 This is a schematic diagram showing the position of the virtual top surface in the case of sharpening in the first embodiment of this disclosure;

[0029] Figure 5 This is a typical simulation result of the ablation morphology evolution process of a typical single fiber in the first embodiment of this disclosure;

[0030] Figure 6 The above are typical simulation results of the ablation morphology of typical composite materials in the first embodiment of this disclosure;

[0031] Figure 7 This is a schematic diagram of the structure of the device for tracking the evolution of the ablation morphology interface of composite materials in the second embodiment of this disclosure. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0033] In thermal boundary environments such as aerodynamic heating, material surfaces exhibit varying degrees of ablation. The accuracy of ablation shape evolution simulation is crucial for simulating material thermal response and evaluating thermal performance. Ablation shape evolution simulation falls under the category of tracking complex moving interfaces. Simulation methods applicable to this type of problem include the Eulerian method and the Lagrangian method. The Eulerian method generally requires a sufficiently fine mesh in the computational domain during the tracking of the ablated surface, thus requiring a relatively large computational load. The Lagrangian method, on the other hand, calculates the normal velocity of each mesh point on the ablated surface and generates new mesh points. At a new time point, it regenerates the ablated surface using all newly generated mesh points, requiring a relatively smaller mesh size. However, it needs to address mesh distortion and non-physical distortion issues that may arise due to interface mesh evolution.

[0034] Because the Lagrangian method generally requires the development of targeted mesh distortion and reconstruction strategies when dealing with mesh distortion and non-physical mesh distortion problems that may occur during interface mesh evolution, and the development is quite difficult, most current composite ablation morphology interface evolution tracking methods adopt the Eulerian method. These methods include the VOF method and the Level Set method, but these methods often require sufficiently fine mesh division of the computational domain, and the computational load is often very large when facing large deformation ablation problems, resulting in relatively low overall computational efficiency.

[0035] To address the aforementioned problems, the first embodiment of this disclosure provides a method for tracking the evolution of the ablation morphology interface of a composite material. By performing a Lagrangian-based evolution analysis on the ablation morphology of the composite material at various time steps, the evolution process of the interface morphology is formed, as shown in the flowchart below. Figure 1 As shown, the main steps include the following:

[0036] S10, initialization steps, include at least: constructing a physical model of the composite material, and based on the size of the physical model, using two two-dimensional surface meshes to characterize the ablation plane of the matrix and the outer contour surface of the reinforcement, and setting a virtual top surface to describe the theoretical ablation position of the top of the reinforcement.

[0037] For a specific composite material, whose structure includes at least a reinforcement and a matrix, a physical model is first constructed based on the actual structure of the composite material. Then, using the specific dimensions of the physical model, a two-dimensional surface mesh is used to characterize the ablation plane of the matrix and the outer contour surface of the reinforcement. When meshing, the ablation plane of the matrix is ​​used as the reference. When meshing the outer contour surface of the reinforcement, the radial mesh lines are parallel to the ablation plane of the matrix, forming a mesh as shown below. Figure 2 The mesh generation result shown is denoted as n, where the number of mesh points in the reinforcement is denoted as n. r *n z n r n is the number of radial grid points. z The number of axial grid points is then defined. A virtual top surface is then set to characterize the theoretical ablation position of the top of the reinforcement before the ablation morphology of the cylindrical fiber reinforcement evolves into a cone, serving as a criterion for subsequent reinforcement tip ablation.

[0038] It should be noted that this embodiment establishes a coordinate system with the bottom end face of the reinforcement as the XY-axis plane and the normal direction of the XY-axis plane as the Z-axis direction, such as... Figure 1 As shown, the coordinates of each grid point are described based on this coordinate system. Corresponding to the virtual top surface, its initial position coincides with the substrate ablation plane, and its coordinates are denoted as z. up That is, it is mainly described by its height.

[0039] S20, the ablation rate calculation step includes at least: calculating the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface based on the surface thermal environment parameters of the composite material.

[0040] Ablation rate refers to the rate at which surface material is consumed or removed from a material under high temperature, high-speed airflow, or other extreme conditions due to thermochemical reactions. It is commonly used to describe the loss of material surface material over time and is a key parameter for evaluating a material's ablation resistance. The evolution of the ablation interface is a process that requires long-term tracking. In this embodiment, the ablation interface morphology is determined at each fixed time step, thereby enabling the tracking of the interface morphology evolution process. Therefore, by calculating the ablation rate at each time step, the accuracy of the interface morphology evolution can be effectively improved.

[0041] In the calculation of the ablation rate, the ablation rate step is affected by the physical and chemical properties of the material itself, and is also closely related to the external environmental conditions. Furthermore, different grid points may have different environmental conditions. In this embodiment, when calculating the ablation rate of each grid point, the surface thermal environment parameters of each grid point are used, including but not limited to the local temperature, pressure, and surface gas flow thermal environment parameters of the grid point. Moreover, as the time step increases, the surface thermal environment parameters of the grid point will also change.

[0042] In practical ablation rate calculations, common methods such as physical modeling, empirical formulas, and numerical simulations can be used. This embodiment employs thermochemical ablation theory, which can describe in detail the chemical reactions and mass migration processes of materials at high temperatures. It offers high accuracy in predicting ablation rates and has wider applicability. For composite materials, it more accurately reflects the ablation behavior of actual materials. More importantly, this embodiment addresses the issue of non-physical mesh distortion that may occur in the Lagrange method. The ablation rate provided by thermochemical ablation theory helps maintain mesh quality and simplifies the mesh reconstruction process.

[0043] S30, the grid point coordinate calculation steps include at least: determining the ablation direction of each grid point, and combining the ablation rate of the grid point to determine the spatial coordinates of each grid point at the current time step.

[0044] After determining the ablation rate of each grid point, the ablation direction of each grid point is determined. Combined with a fixed time step length, the new position of each grid point after ablation within the current time step can be determined and described using spatial coordinates. In some embodiments, the ablation direction can be calculated by combining the normal direction, local heat flow direction, chemical reaction front, etc. This embodiment mainly uses the four-point average normal as the ablation movement direction of the grid point. The ablation movement direction of each grid point is determined by calculating the average normal of the surrounding four grid points. This method ensures that a relatively reasonable ablation direction can be obtained even on complex three-dimensional shapes.

[0045] S40, the topography reconstruction step includes at least: performing non-physical distortion mesh reconstruction on the first topography interface formed by the spatial coordinates of all mesh points, and determining the reconstruction coordinates of each mesh point after reconstruction to form a second topography interface.

[0046] Once the spatial coordinates of each grid point after ablation are determined, the first morphological interface formed by all grid points at the current time step can be identified. However, the morphology of each grid point within the first morphological interface may deviate from actual physical behavior, failing to reflect the true physical process. This is particularly problematic in morphological interface evolution tracking, severely impacting the accurate simulation of the ablation process. Therefore, this embodiment reconstructs the distorted grid point positions through grid reconstruction to form a second morphological interface, restoring the rationality of the grid division.

[0047] In this embodiment, the principle of initial mesh generation is still followed during reconstruction: the radial mesh lines of the reinforcement are parallel to the ablation plane of the substrate. Non-physical distortion meshes and non-parallel mesh lines are reconstructed on the first morphology interface, and the reconstructed coordinates of each mesh point are determined. Ensuring the parallelism of the radial mesh lines to the ablation plane of the substrate during reconstruction reduces the difficulty of non-physical distortion detection and reconstruction, and ensures better interface morphology tracking.

[0048] When performing a refactoring, you can refer to the following steps:

[0049] Step S1: Define the normal of the material matrix phase plane, perform horizontal expansion preprocessing on the curved space quadrilateral mesh of the initial shape of the ablation interface of a single cylindrical fiber to obtain a planar mesh, and update the ablation interface mesh points by interpolation according to the normal of the material matrix phase plane, so that all radial mesh lines of the ablation interface mesh are parallel to the mesh lines of the matrix plane, thereby obtaining the horizontal mesh of the ablation interface after horizontal processing, wherein the normal of the material matrix phase plane is the z-coordinate direction.

[0050] Step S2: Based on the horizontal grid of the ablation interface of a single cylindrical fiber, perform grid distortion judgment and reconstruction update for each layer of grid points; based on the grid layer, traverse and determine the intersecting line segments in the grid layer, determine the four grid points corresponding to the intersecting line segments in sequence according to the traversal direction, and determine the number of grid points between the first and last traversed grid points, as well as the number of grid points between the other two grid points. Move the grid points on the side with more grid points to the two grid points with fewer grid points and distribute them at equal distances. Finally, move the grid point closest to the intersection point and cover the intersection point to complete the grid reconstruction of the corresponding grid layer.

[0051] Step S3 involves completing the distortion judgment and reconstruction update of all mesh layers based on step S2, and completing the mesh reconstruction of each individual cylindrical fiber based on steps S1 to S2, thereby realizing the mesh reconstruction of the material ablation interface. This yields the coordinates of the spatial mesh points of the material ablation interface after reconstruction, ultimately obtaining the ablation shape mesh information without physical distortion or loss of quality at the current calculation time.

[0052] Step S1 specifically includes the following steps:

[0053] Step S11 defines the normal direction of the material matrix phase plane, where the normal direction of the material matrix phase plane is the z-coordinate direction. Before material ablation occurs, the fibers and the surrounding matrix form an initial plane, and the ablation direction of the matrix will always remain parallel to this matrix plane. That is, the material matrix phase plane is determined and not arbitrary.

[0054] Step S12: Based on the defined normal of the material matrix phase plane, the initial shape of the ablation interface of a single cylindrical fiber and the curved space quadrilateral mesh are horizontalized to obtain an nr×ns planar mesh, where nr is the number of circumferential meshes of the fiber and ns is the number of axial meshes of the fiber.

[0055] Step S13: Based on the planar mesh, reconstruct the z-axis spacing ΔZj1 (ΔZj1 > ΔZ1) according to the set mesh, where ΔZ1 is the z-axis spacing of the first layer mesh. From the first layer to the last layer (ns layer), take Zk = Zk-1 + ΔZj1, k = 1, 2, 3, ..., ns. Using Zk as the interpolation target height, for each column (1, 2, 3, ..., nr) of mesh points with the same index as the current layer number, perform interpolation updates based on the coordinate values ​​of the corresponding mesh points in the current column and current layer, as well as the coordinate values ​​of the original mesh points. This ensures that all radial mesh lines of the ablation interface mesh are parallel to the substrate plane, resulting in a "horizontally processed" ablation interface mesh. (Reference) Figure 3 The diagram shown is a schematic of the ablation interface mesh obtained after horizontal processing in this embodiment.

[0056] In this embodiment, the nr×ns planar mesh obtained through step S1 or step S12 does not require z-coordinate interpolation update for the unablated portion in the z-direction. Therefore, to reduce unnecessary "interpolation update" actions and save computer resources, it is necessary to first determine the mesh layer that needs "interpolation update," that is, to determine the mesh layer that needs to be reconstructed. Therefore, after step S1 updates the ablation interface mesh points through interpolation or before step S13, the following steps are also included:

[0057] Step S121: Based on the planar mesh, starting from the bottom mesh layer of the fiber planar mesh, determine the maximum z-coordinate of the mesh within the layer. j,max Is it higher than the z-coordinate value corresponding to the current position of the matrix phase plane? matrix If z j,max >z matrix If the value is 0, then it is the mesh layer that needs to be reconstructed. The mesh layers that need to be reconstructed are determined layer by layer from bottom to top.

[0058] In one specific embodiment, when determining the mesh layer to be reconstructed layer by layer from bottom to top, the mesh layers that need to be reconstructed are sequentially marked jt (t = 1, 2, 3, ..., nz).

[0059] In one embodiment, the evolution of the ablation mesh is likely to result in mesh line intersections. The mesh after the "horizontalization" process in step S1 will also result in mesh line intersections. Therefore, after processing the z coordinates of all mesh points through the above steps S11-S13, it is necessary to determine and reconstruct the distortion of the x and y coordinates of each layer of mesh. The distortion determination is the problem of whether the line segments between mesh points in the plane intersect.

[0060] In one specific embodiment, based on the horizontal mesh of the ablation interface of a single cylindrical fiber, the specific steps for mesh distortion judgment and reconstruction update of each mesh point are as follows:

[0061] Step S21: Based on any grid layer, number the coordinates of all grid points in the plane in counterclockwise order.

[0062] Step S22: According to the grid point index i from 1 to nr-3, sequentially determine the grid line PiPi+1 and grid lines Pi+1Pi+2, Pi+2Pi+3, ... If there is an intersection, proceed to step S23; otherwise, determine the intersection of grid lines based on the next (i+1) grid point.

[0063] In step S23, if grid segments intersect, the four grid points corresponding to the intersecting grid lines are numbered sequentially from smallest to largest as calculation point ①, calculation point ②, calculation point ③, and calculation point ④, and the intersection point is numbered Pc.

[0064] Step S24: Count the number of grid points between calculation points ② and ③ and calculation points ① and ④ respectively, which are N23 and N14.

[0065] Step S25, if N 23 ≤N 14 Then, all grid points located between the two grid points corresponding to calculation points ② and ③ will be moved horizontally and distributed at equal distances between the two grid points corresponding to calculation points ① and ④, and the grid point closest to Pc will be moved and cover point Pc.

[0066] Step S26, conversely, if N 23 >N 14 Then, all grid points located between the two grid points corresponding to calculation points ① and ④ will be moved horizontally and distributed at equal distances between the two grid points corresponding to calculation points ② and ③, and the grid point closest to Pc will be moved to point Pc.

[0067] Step S27: Repeat steps S23 to S26 until the grid points are completed. Distortion detection and reconstruction of grid points.

[0068] Compared to other mesh reconstruction methods, the method in this embodiment preprocesses the spatial quadrilateral mesh of the composite ablation interface by "horizontalizing" it. This allows the determination of whether the ablation interface mesh is distorted to be performed only within the planar mesh points of each "horizontallyized" layer, solving the problem of difficult mesh distortion judgment in composite ablation interfaces under large ablation deformation conditions. Practice has shown that it has high accuracy and analysis efficiency. Compared to other mesh reconstruction methods, this embodiment reduces the mesh distortion problem that may occur during the evolution of the composite ablation interface to the intersection problem of line segments in the plane, and further categorizes the intersection problem into two cases for separate reconstruction processing. This method features high efficiency in mesh distortion judgment and fast distortion reconstruction processing, which is beneficial to improving the overall simulation efficiency of the composite ablation interface mesh evolution process.

[0069] S50, the burn-off determination step includes at least the following: updating the position of the virtual top surface at the current time step according to the ablation rate of the virtual top surface, determining the coordinates of the virtual top surface according to the reconstructed coordinates of all grid points, determining the current area of ​​the virtual top surface according to the coordinates of the virtual top surface, and determining that the reinforcement is burn-off if the current area is less than α times the original area of ​​the virtual top surface; otherwise, determining that the reinforcement is not burn-off.

[0070] Burnt-sharp phenomenon refers to the formation of sharp points at the top of the reinforcement due to ablation. Identifying burnt-sharp phenomena is a crucial step in tracking the evolution of the material's ablation interface morphology. It not only helps accurately capture changes in the material's surface geometry but also improves simulation accuracy and computational efficiency. In this embodiment, burnt-sharp identification first involves updating the position of the virtual top surface. The ablation rate of the virtual top surface is calculated synchronously during the ablation rate calculation step. Combined with the time step, the theoretical position of the reinforcement's top surface after ablation can be determined. Subsequently, based on the reconstructed coordinates of each grid point, the coordinates of the virtual top surface at its current position are determined. In practice, the coordinates of each point on the outer periphery of the virtual top surface can be obtained from the reconstructed coordinates of the grid points using an interpolation algorithm. Based on these coordinates, the area A of the virtual top surface at this point is determined. up This serves as the basis for determining whether the tip is burnt.

[0071] Specifically, a criterion coefficient α is predefined for the fiber morphology to evolve into a cone, and the area A of the virtual apex surface is... up If the area is less than α times the original area of ​​the virtual top surface, the reinforcement is determined to have evolved into a cone shape; otherwise, the reinforcement is determined not to have been sharpened. In some embodiments, the value of the determination coefficient α should be less than 1.0E-5. Figure 3This diagram shows the position of the virtual top surface when it is not scorched. Figure 4 This shows the position of the virtual top surface when the tip is burned.

[0072] S60, the reinforcement mesh update step includes at least the following: if the reinforcement is determined not to be spiked, the virtual top surface is used as the actual top surface of the reinforcement, and the updated coordinates of each mesh point in the actual top surface are determined according to the current coordinates of the virtual top surface, and the interface topography mesh is formed at the current time step; if the reinforcement is determined to be spiked, the actual height of the reinforcement at the current time step is determined, and the reconstructed coordinates of all mesh points exceeding the actual height are deleted, so as to form the interface topography mesh.

[0073] For the two different ablation scenarios determined in step S50 above, this embodiment employs different methods when updating the reinforcement mesh to ensure mesh quality and computational efficiency during the simulation. Specifically, for the case where the reinforcement is not ablated, the positional relationship between the virtual top surface and the second morphology interface is as follows: Figure 3 As shown, at this point, the virtual top surface is used as the actual top surface of the augmented body, and the height is higher than the virtual top surface z. up The mesh points of the second morphology interface are deleted, and the coordinates of each mesh point in the actual top surface are determined based on the coordinates of the virtual end face obtained in the burnt-out determination step. This coordinates are then combined with the reconstructed coordinates of the remaining mesh points to form the interface morphology mesh for the current time step. For the case of reinforced body burnt-out, the positional relationship between the virtual top surface and the second morphology interface is as follows: Figure 4 As shown, the top of the reinforced body has now degenerated into a cusp, and the height z of the highest point of the current second topographic interface is required. matrix and the current height z of the virtual top face up The height corresponding to the minimum radial cross-sectional area of ​​the reinforcement is calculated and used as the actual height z of the reinforcement's actual shape at the current time step. max In the second morphology interface, the reconstructed coordinates of grid points with heights greater than the actual heights are deleted to form the interface morphology grid at the current time step.

[0074] In this embodiment, considering the characteristics of geometric morphology changes during material ablation, especially when sharp points are formed at the top of the reinforcement, in order to ensure the accuracy and efficiency of the simulation process, two different processing methods are combined to determine the interface morphology mesh. At the same time, by removing invalid mesh points, the number of mesh points calculated in the next time step can be further reduced, thereby improving computational efficiency.

[0075] S70, the evolution tracking and output steps, include at least: detecting whether the evolution end time has been reached; if the evolution end time has not been reached, updating the time step and surface thermal environment parameters, and re-executing the ablation rate calculation step; if the evolution end time has been reached, outputting the interface morphology mesh at each time step, and obtaining the evolution tracking results of the composite material ablation morphology interface.

[0076] After step S60 is executed, the mesh of the ablation morphology interface of the composite material at the current time step can be obtained. Then, it is determined whether the evolution end time has been reached. If the current time step has not reached the evolution end time, the evolution tracking of the next time step is required. At this time, the time step and surface thermal environment parameters are updated, and the ablation rate calculation step is re-executed. This process is repeated until the evolution end time is reached. If the evolution end time has been reached after the current time step, the cross-sectional morphology mesh corresponding to each time step in all time steps before the evolution end is output and sorted according to the time step to obtain the evolution tracking result of the ablation morphology interface of the composite material.

[0077] It should be noted that this embodiment is applicable to, but not limited to, tracking and simulating the ablation morphology interface evolution process at the particle / fiber scale, fiber bundle scale, and macroscopic model component scale of various fiber-reinforced composite materials and particle-reinforced composite materials. Figure 5 Typical simulation results of the evolution of ablation morphology in a single fiber are shown. Figure 6 Typical simulation results of ablation morphology of typical composite materials are shown.

[0078] This embodiment proposes an evolution tracking method for the ablation morphology interface of composite materials based on the Lagrange method. By combining the ablation regression of the virtual top surface and the strategy of determining the ablation tip of the reinforcement, the difficulty of determining and reconstructing non-physical distortions during the interface mesh evolution is greatly reduced. It solves the mesh distortion and deformation problems that may occur under ablation deformation. It has the characteristics of high accuracy in morphology interface tracking and easy implementation of simulation tracking strategy. At the same time, the overall mesh computation is small, which improves the computational efficiency.

[0079] Based on the same inventive concept, the second embodiment of this disclosure provides an evolution tracking device for the ablation morphology interface of a composite material, the structural schematic diagram of which is shown below. Figure 7 As shown, it mainly includes the following modules:

[0080] Initialization module 10 is used to construct the physical model of the composite material, and according to the size of the physical model, two two-dimensional surface meshes are used to characterize the ablation plane of the matrix and the outer contour surface of the reinforcement, and a virtual top surface is set to describe the theoretical ablation position of the top of the reinforcement.

[0081] The ablation rate calculation module 20 is used to calculate the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface based on the surface thermal environment parameters of the composite material.

[0082] The grid point coordinate calculation module 30 is used to determine the ablation direction of each grid point and, in combination with the ablation rate of the grid point, determine the spatial coordinates of each grid point at the current time step.

[0083] The topography reconstruction module 40 is used to perform non-physical distortion mesh reconstruction on the first topography interface formed by the spatial coordinates of all grid points, and to determine the reconstruction coordinates of each grid point after reconstruction, thus forming a second topography interface.

[0084] The ablation determination module 50 is used to update the position of the virtual top surface at the current time step according to the ablation rate of the virtual top surface, and determine the coordinates of the virtual top surface according to the reconstructed coordinates of all grid points, and determine the current area of ​​the virtual top surface according to the coordinates of the virtual top surface. If the current area is less than α times the original area of ​​the virtual top surface, the reinforcement is determined to be ablated; otherwise, the reinforcement is determined not to be ablated.

[0085] The reinforcement mesh update module 60 is used to determine the actual top surface of the reinforcement when it is determined that the reinforcement is not burned, and to determine the updated coordinates of each mesh point in the actual top surface according to the coordinates of the virtual top surface, and to form the interface topography mesh at the current time step; when it is determined that the reinforcement is burned, it determines the actual height of the reinforcement at the current time step, and deletes the reconstructed coordinates of all mesh points that exceed the actual height, so as to form the interface topography mesh.

[0086] The evolution tracking and output module 70 is used to detect whether the evolution end time has been reached. If the evolution end time has not been reached, the time step and surface thermal environment parameters are updated, and the ablation rate calculation module is called again. If the evolution end time has been reached, the interface morphology mesh at each time step is output to obtain the evolution tracking results of the ablation morphology interface of the composite material.

[0087] In some embodiments, the initialization module 10 specifically adopts the principle of keeping the radial grid lines parallel to the ablation plane of the substrate to divide the outer contour surface grid of the reinforcement.

[0088] In some embodiments, the ablation rate calculation module 20 specifically uses the thermochemical ablation theory calculation method to calculate the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface.

[0089] In some embodiments, the topography reconstruction module 40 specifically adopts the principle of keeping the radial grid lines parallel to the ablation plane of the substrate, performs non-physical distortion grid judgment and non-parallel grid line reconstruction calculation on the first topography interface, and determines the reconstruction coordinates of each grid point after reconstruction to form a second topography interface.

[0090] In some embodiments, the burnt tip determination module 50 is specifically used to determine the coordinates of the outer periphery of the virtual top surface by means of the reconstructed coordinates of all the grid points through an interpolation algorithm.

[0091] In some embodiments, the augmentation mesh update module 60 is specifically used to calculate the height corresponding to the minimum radial cross-sectional area of ​​the augmentation body between the height of the highest point of the second topographic interface and the current height of the virtual top surface, as the actual height of the actual topographic shape of the augmentation body at the current time step, and to delete the reconstructed coordinates of mesh points whose height is greater than the actual height in the second topographic interface.

[0092] It should be noted that this embodiment is applicable to, but not limited to, tracking and simulating the ablation morphology interface evolution process at the particle / fiber scale, fiber bundle scale, and macroscopic model component scale of various fiber-reinforced composite materials and particle-reinforced composite materials. The specific functions that each module can achieve in this embodiment have been described in detail in the first embodiment, and will not be repeated here.

[0093] This embodiment proposes an evolution tracking method for the ablation morphology interface of composite materials based on the Lagrange method. By combining the ablation regression of the virtual top surface with the strategy of determining the ablation tip of the reinforcement, the difficulty of determining and reconstructing non-physical distortions during the interface mesh evolution is greatly reduced. It solves the mesh distortion and deformation problems that may occur under ablation deformation. It has the characteristics of high accuracy in morphology interface tracking and easy implementation of simulation tracking strategy. At the same time, the overall mesh computation is small, which improves the computational efficiency.

[0094] Based on the same inventive concept, the third embodiment of this disclosure provides a storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for tracking the evolution of ablation morphology interfaces of composite materials as described in the first embodiment of this disclosure.

[0095] Based on the same inventive concept, the fourth embodiment of this disclosure provides an electronic device, including at least a memory and a processor. The memory stores a computer program, and when the processor executes the computer program in the memory, it implements the steps of the method for tracking the evolution of ablation morphology interfaces of composite materials as described in the first embodiment of this disclosure.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure 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 this disclosure.

Claims

1. A method for tracking the evolution of ablation morphology interfaces of composite materials, characterized in that, include: The initialization steps include at least: constructing a physical model of the composite material, and based on the size of the physical model, using two two-dimensional surface meshes to characterize the ablation plane of the matrix and the outer contour surface of the reinforcement, and setting a virtual top surface to describe the theoretical ablation position of the top of the reinforcement; The ablation rate calculation step includes at least: calculating the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface based on the surface thermal environment parameters of the composite material. The grid point coordinate calculation steps include at least: determining the ablation direction of each grid point, and determining the spatial coordinates of each grid point at the current time step in combination with the ablation rate of the grid point; The topography reconstruction step includes at least: performing non-physical distortion mesh reconstruction on the first topography interface formed by the spatial coordinates of all the mesh points, and determining the reconstruction coordinates of each mesh point after reconstruction to form a second topography interface; The ablation determination step includes at least the following steps: updating the position of the virtual top surface at the current time step according to the ablation rate of the virtual top surface, determining the coordinates of the virtual top surface according to the reconstructed coordinates of all the grid points, determining the current area of ​​the virtual top surface according to the coordinates of the virtual top surface, and determining the ablation of the reinforcement if the current area is less than α times the original area of ​​the virtual top surface; otherwise, determining that the reinforcement is not ablated. The augmentation mesh update step includes at least the following: if it is determined that the augmentation is not tipped, the virtual top surface is used as the actual top surface of the augmentation, and the updated coordinates of each mesh point in the actual top surface are determined according to the coordinates of the virtual top surface, and an interface topography mesh is formed at the current time step; if it is determined that the augmentation is tipped, the actual height of the augmentation at the current time step is determined, and the reconstructed coordinates of all mesh points exceeding the actual height are deleted to form an interface topography mesh. The evolution tracking and output steps include at least: detecting whether the evolution end time has been reached; if the evolution end time has not been reached, updating the time step and surface thermal environment parameters, and re-executing the ablation rate calculation step; if the evolution end time has been reached, outputting the interface morphology mesh at each time step, and obtaining the evolution tracking results of the composite material ablation morphology interface.

2. The evolutionary tracing method according to claim 1, characterized in that, In the initialization step, the outer contour surface mesh of the reinforcement is divided according to the principle that the radial mesh lines are parallel to the ablation plane of the substrate.

3. The evolutionary tracing method according to claim 1, characterized in that, In the ablation rate calculation step, the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface are calculated using the thermochemical ablation theory calculation method.

4. The evolution tracking method according to claim 1, characterized in that, In the morphology reconstruction step, the principle of keeping the radial grid lines parallel to the ablation plane of the substrate is adopted to perform non-physical distortion grid judgment and non-parallel grid line reconstruction calculation on the first morphology interface, and determine the reconstruction coordinates of each grid point after reconstruction to form the second morphology interface.

5. The evolution tracking method according to claim 1, characterized in that, In the burnt-out determination step, determining the coordinates of the virtual top surface based on the reconstructed coordinates of all the grid points includes: The coordinates of the outer perimeter of the virtual top surface are determined by an interpolation algorithm using the reconstructed coordinates of all the grid points.

6. The evolutionary tracing method according to claim 1, characterized in that, In the augmentation mesh update step, determining the actual height of the augmentation at the current time step and deleting the reconstructed coordinates of all mesh points exceeding the actual height includes: Between the height of the highest point on the second topographic interface and the current height of the virtual top surface, calculate the height corresponding to the minimum radial cross-sectional area of ​​the augmentation as the actual height of the augmentation's actual topographic shape at the current time step. In the second topographic interface, delete the reconstructed coordinates of grid points whose height is greater than the actual height.

7. The evolution tracking method according to any one of claims 1 to 6, characterized in that, The composite material includes at least fiber-reinforced composite material or particle-reinforced composite material.

8. A device for tracking the evolution of ablation morphology interfaces of composite materials, characterized in that, include: An initialization module is used to construct a physical model of the composite material, and based on the size of the physical model, two two-dimensional surface meshes are used to characterize the ablation plane of the matrix and the outer contour surface of the reinforcement, and a virtual top surface is set to describe the theoretical ablation position of the top of the reinforcement. The ablation rate calculation module is used to calculate the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface based on the surface thermal environment parameters of the composite material. The grid point coordinate calculation module is used to determine the ablation direction of each grid point and, in combination with the ablation rate of the grid point, determine the spatial coordinates of each grid point at the current time step. The topography reconstruction module is used to perform non-physical distortion mesh reconstruction on the first topography interface formed by the spatial coordinates of all the mesh points, and to determine the reconstruction coordinates of each mesh point after reconstruction, thus forming a second topography interface. The ablation determination module is used to update the position of the virtual top surface at the current time step according to the ablation rate of the virtual top surface, determine the coordinates of the virtual top surface according to the reconstructed coordinates of all the grid points, and determine the current area of ​​the virtual top surface according to the coordinates of the virtual top surface. If the current area is less than α times the original area of ​​the virtual top surface, the reinforcement is determined to be ablated; otherwise, the reinforcement is determined not to be ablated. The augmentation mesh update module is used to, when it is determined that the augmentation is not sharpened, use the virtual top surface as the actual top surface of the augmentation, and determine the updated coordinates of each mesh point in the actual top surface according to the coordinates of the virtual top surface, and form the interface topography mesh at the current time step; when it is determined that the augmentation is sharpened, determine the actual height of the augmentation at the current time step, and delete the reconstructed coordinates of all mesh points that exceed the actual height, so as to form the interface topography mesh. The evolution tracking and output module is used to detect whether the evolution end time has been reached. If the evolution end time has not been reached, the time step and surface thermal environment parameters are updated, and the ablation rate calculation module is called again. If the evolution end time has been reached, the interface morphology mesh at each time step is output to obtain the evolution tracking results of the composite material ablation morphology interface.

9. A storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for tracking the evolution of the ablation morphology interface of the composite material as described in any one of claims 1 to 7.

10. An electronic device, comprising at least a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program on the memory, it implements the steps of the method for tracking the evolution of the ablation morphology interface of the composite material as described in any one of claims 1 to 7.

Images