Evolution tracking method and device for ablation morphology interface of composite material

Abstract

The invention provides an evolution tracking method and device for a composite material ablation morphology interface. The method comprises an initialization step, an ablation rate calculation step, a grid point coordinate calculation step, a morphology reconstruction step, a burning tip judgment step, an enhancement body grid updating step and an evolution tracking and output step. The invention provides an evolution tracking mode of a composite material ablation morphology interface based on a Lagrangian method, and the method is combined with the ablation regression of a virtual top end surface and the strategy cooperative application of reinforcement burning tip judgment, thereby greatly reducing the judgment and reconstruction difficulty of non-physical distortion in an interface grid evolution process. According to the method, the problems of grid distortion and distortion possibly occurring under the ablation deformation condition are solved, the method has the advantages of being high in morphology interface tracking accuracy and easy in simulation tracking strategy implementation, meanwhile, the overall grid calculation amount of the scheme is small, and the calculation efficiency is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of aircraft thermal protection design and evaluation, and in particular to a method, device, storage medium and electronic equipment for tracking the evolution of composite material ablation morphology interface. Background Art

[0002] Under thermal boundary environments such as aerodynamic heating, different degrees of ablation will occur on the surface of the material. The accuracy of the simulation of the evolution of the ablation shape is crucial to the simulation of the thermal response of the material and the evaluation of the thermal performance. The simulation of the evolution of the ablation shape belongs to the tracking problem of complex moving interfaces. The simulation methods that can be used for such problems include the Euler method and the Lagrangian method. The Euler method generally requires that the grid division of the calculation area is fine enough in the process of tracking the ablation surface, so the amount of calculation required is relatively large. The Lagrangian method calculates the normal velocity of each grid point on the ablation surface and generates new grid points, and regenerates the ablation surface with all the newly generated grid points at the new moment. The grid size requirement is relatively small, but it is necessary to solve the grid distortion and non-physical distortion of the grid caused by the evolution of the interface grid.

[0003] Since 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 be caused by interface mesh evolution, and the research and development is difficult, most of the current methods for tracking the interface evolution of composite ablation morphology use the Euler method, which includes the VOF (Volume of Fluid) method, the Level Set method, etc. However, these methods often require the calculation area to be fine enough, and the amount of calculation when facing large deformation ablation problems is often large, and the overall calculation efficiency is relatively low. Summary of the invention

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

[0005] The embodiment of the present disclosure adopts the following technical solution: a method for tracking the evolution of composite material ablation morphology interface, comprising:

[0006] The initialization step at least includes: constructing a physical model of the composite material, and using two two-dimensional surface meshes to characterize the matrix ablation plane and the peripheral contour surface of the reinforcement according to the size of the physical model, and setting a virtual top surface for describing the theoretical ablation position of the top of the reinforcement;

[0007] The ablation rate calculation step at least comprises: calculating the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface according to the surface thermal environment parameters of the composite material;

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

[0009] The morphology reconstruction step at least includes: performing non-physical distortion network grid reconstruction on the first morphology 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 morphology interface;

[0010] The burn tip determination step at least includes: 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, and determining the current area of ​​the virtual top surface according to the coordinates of the virtual top surface, and determining that the reinforcement is burnt tip when the current area is less than α times the original area of ​​the virtual top surface, otherwise, determining that the reinforcement is not burnt tip;

[0011] The reinforcement mesh updating step at least includes: when it is determined that the reinforcement is not burnt, taking the virtual top surface as the actual top surface of the reinforcement, and determining the updated coordinates of each grid point in the actual top surface according to the coordinates of the virtual top surface, and forming an interface morphology network mesh at the current time step; when it is determined that the reinforcement is burnt, determining the actual height of the reinforcement at the current time step, and deleting the reconstructed coordinates of all grid points exceeding the actual height to form an interface morphology network mesh;

[0012] The evolution tracking and output step at least includes: detecting whether the evolution end time has been reached, updating the time step and the surface thermal environment parameters if the evolution end time has not been reached, and re-executing the ablation rate calculation step, and outputting the interface morphology network grid at each time step if the evolution end time has been reached to obtain the evolution tracking result of the composite material ablation morphology interface.

[0013] The disclosed embodiment also provides a composite material ablation morphology interface evolution tracking device, comprising:

[0014] An initialization module is used to construct a 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 matrix ablation plane and the peripheral 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] an ablation rate calculation module, used to calculate the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface according to the surface thermal environment parameters of the composite material;

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

[0017] A morphology reconstruction module, used for performing non-physical distortion network grid reconstruction on the first morphology 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 morphology interface;

[0018] a burn tip determination module, used for 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, and determining the current area of ​​the virtual top surface according to the coordinates of the virtual top surface, and determining that the reinforcement is burnt tip when the current area is less than α times the original area of ​​the virtual top surface, otherwise, determining that the reinforcement is not burnt tip;

[0019] A reinforcement mesh updating module is used to, when it is determined that the reinforcement is not burnt, use the virtual top surface as the actual top surface of the reinforcement, and determine the updated coordinates of each grid point in the actual top surface according to the coordinates of the virtual top surface, and form an interface morphology mesh at the current time step; when it is determined that the reinforcement is burnt, determine the actual height of the reinforcement at the current time step, and delete the reconstructed coordinates of all grid points exceeding the actual height to form an interface morphology 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 re-called. If the evolution end time has been reached, the interface morphology network grid at each time step is output to obtain the evolution tracking result of the composite material ablation morphology interface.

[0021] The embodiment of the present disclosure further provides a storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for tracking the evolution of the ablation morphology interface of the composite material.

[0022] The embodiment of the present disclosure also provides an electronic device, comprising at least a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned method for tracking the evolution of the ablation morphology interface of the composite material when executing the computer program on the memory.

[0023] The beneficial effects of the embodiments of the present disclosure are as follows: a method for tracking the evolution of the ablation morphology interface of a composite material based on the Lagrangian method is proposed, which is combined with the ablation regression of the virtual top surface and the strategy for determining the burnt tip of the reinforcement for coordinated application, which greatly reduces the difficulty of determining and reconstructing non-physical distortion during the evolution of the interface mesh, solves the mesh distortion and distortion problems that may occur in the case of ablation deformation, has the characteristics of high accuracy in morphology interface tracking and easy implementation of simulation tracking strategies, and at the same time, the overall mesh calculation amount of the scheme is small, which improves the calculation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 It is a flow chart of the evolution tracking method of the composite material ablation morphology interface in the first embodiment of the present disclosure;

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

[0027] Figure 3 It is a schematic diagram of the position of the virtual top end surface in the case where the tip is not burned in the first embodiment of the present disclosure;

[0028] Figure 4 It is a schematic diagram of the position of the virtual top end surface in the case of burning tip in the first embodiment of the present disclosure;

[0029] Figure 5 The typical simulation results of the ablation morphology evolution process of a typical single fiber in the first embodiment of the present disclosure;

[0030] Figure 6 is a typical simulation result of the ablation morphology of a typical composite material in the first embodiment of the present disclosure;

[0031] Figure 7 It is a schematic diagram of the structure of the evolution tracking device of the composite material ablation morphology interface in the second embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the following will be combined with the drawings in one or more embodiments of this specification to clearly and completely describe the technical solutions in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this document.

[0033] Under thermal boundary environments such as aerodynamic heating, different degrees of ablation will occur on the surface of the material. The accuracy of the simulation of the evolution of the ablation shape is crucial to the simulation of the thermal response of the material and the evaluation of the thermal performance. The simulation of the evolution of the ablation shape belongs to the tracking problem of complex moving interfaces. The simulation methods that can be used for such problems include the Euler method and the Lagrangian method. The Euler method generally requires that the grid division of the calculation area is fine enough in the process of tracking the ablation surface, so the amount of calculation required is relatively large. The Lagrangian method calculates the normal velocity of each grid point on the ablation surface and generates new grid points, and regenerates the ablation surface with all the newly generated grid points at the new moment. The grid size requirement is relatively small, but it is necessary to solve the grid distortion and non-physical distortion of the grid caused by the evolution of the interface grid.

[0034] Since 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 be caused by interface mesh evolution, and the research and development is difficult, most of the current methods for tracking the interface evolution of composite ablation morphology use the Euler method, which includes the VOF method, the Level Set method, etc. However, these methods often require the calculation area to be fine enough, and the amount of calculation when facing large deformation ablation problems is often large, and the overall calculation efficiency is relatively low.

[0035] In order to solve the above problems, the first embodiment of the present disclosure provides a method for tracking the evolution of the ablation morphology interface of a composite material, by evolving the ablation morphology of the composite material at each time step based on the Lagrangian method to form an evolution process of the interface morphology, and the flow chart thereof is as follows: Figure 1 As shown, it mainly includes the following steps:

[0036] S10, an initialization step, at least includes: constructing a physical model of the composite material, and using two two-dimensional surface meshes to characterize the matrix ablation plane and the peripheral contour surface of the reinforcement according to the size of the physical model, and setting a virtual top surface for describing the theoretical ablation position of the top of the reinforcement.

[0037] For a specific composite material, whose structure includes at least reinforcement and matrix, a physical model is first constructed based on the actual structure of the composite material, and the matrix ablation plane and the outer contour surface of the reinforcement are meshed by two-dimensional surface meshes based on the specific size of the physical model. When meshing, the matrix ablation plane is used as the reference, and when meshing the outer contour surface of the reinforcement, the principle that its radial grid lines are parallel to the matrix ablation plane is adopted to form the following: Figure 2 The meshing result is shown in Figure 2, where the number of mesh points of the reinforcement is recorded as n. r *n z , n r is the number of radial grid points, n z is the number of axial grid points. Then a virtual top surface is 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, which serves as a criterion for the subsequent reinforcement tip burning.

[0038] It should be noted that the present embodiment establishes a coordinate system with the bottom end surface of the reinforcement body 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 in Figure 1, 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 coordinate is marked as z up , that is, it is described primarily by its height.

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

[0040] The ablation rate refers to the speed at which the material on the surface of a material is consumed or removed due to thermochemical reactions under high temperature, high-speed airflow or other extreme conditions. It is usually used to describe the loss of the material surface over time and is a key parameter for evaluating the ablation resistance of the material. The evolution process of the ablation interface is a process that requires long-term tracking. In this embodiment, the ablation interface morphology is determined at each time step in combination with a fixed time step, thereby realizing the tracking of the evolution process of the interface morphology. 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 step 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. Grid points at different locations may also have different environmental conditions. When calculating the ablation rate of each grid point, this embodiment is based on the surface thermal environment parameters of the location of each grid point, including but not limited to the local temperature, pressure and surface gas flow thermal environment parameters of the location of the grid point. As the time step increases, the surface thermal environment parameters of the grid point will also change.

[0042] When calculating the ablation rate in practice, common methods such as physical model method, empirical formula calculation method, numerical simulation method, etc. can be used. This embodiment uses the thermochemical ablation theory calculation method for calculation, which can describe in detail the chemical reaction and material migration process of materials at high temperatures, has high accuracy in predicting the ablation rate, and has wider adaptability. For composite materials, it can more accurately reflect the ablation behavior of actual materials. More importantly, this embodiment uses the ablation rate provided by the thermochemical ablation theory calculation method to help maintain the quality of the mesh and simplify the mesh reconstruction process in order to solve the problem of non-physical distortion of the mesh that may occur in the Lagrangian method.

[0043] S30, a grid point coordinate calculation step, at least includes: 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.

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

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

[0046] After 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 determined. However, the morphology of each grid in the first morphological interface may deviate from the actual physical behavior and cannot reflect the real physical process, especially in the evolution tracking of the morphological interface, which will seriously affect the accurate simulation of the ablation process. Therefore, this embodiment reconstructs the distorted grid point position by grid reconstruction to form a second morphological interface, so that it can restore the rationality of grid division.

[0047] When actually reconstructing in this embodiment, the principle of initial grid division is still followed, that is, the radial grid lines of the reinforcement body are parallel to the ablation plane of the substrate, and the non-physical distortion grid is judged and the non-parallel grid lines are reconstructed for the first morphological interface, and the reconstruction coordinates of each grid point after reconstruction are determined. During the reconstruction process, ensuring that the radial grid lines are parallel to the ablation plane of the substrate can reduce the difficulty of judging and reconstructing non-physical distortion and ensure a better interface morphology tracking effect.

[0048] When refactoring, you can refer to the following steps to implement it:

[0049] Step S1, defining the normal direction of the material matrix phase plane, performing horizontal expansion preprocessing on the curved space quadrilateral grid of the initial shape of the ablation interface of a single cylindrical fiber to obtain a plane grid, and updating the ablation interface grid points by interpolation according to the normal direction of the material matrix phase plane, so that all radial grid lines of the ablation interface grid are parallel to the matrix plane grid lines, thereby obtaining the horizontal grid of the ablation interface after horizontal processing, wherein the normal direction 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, the grid distortion judgment and reconstruction update are performed on each layer of grid points; based on the grid layer, the intersecting line segments in the grid layer are traversed and determined, and the four grid points corresponding to the intersecting line segments are determined in turn according to the traversal direction, and the number of grid points between the first and last traversed two grid points, as well as the number of grid points between the other two grid points are determined, and the grid points on the side with more numbers are moved to between the two grid points with less numbers, and are distributed at equal distances, and finally the grid points closest to the intersection are moved and cover the intersection to complete the grid reconstruction of the corresponding grid layer.

[0051] Step S3, according to step S2, complete the distortion judgment and reconstruction update of all grid layers, and according to step S1 to step S2, complete the grid reconstruction of each single cylindrical fiber, so as to achieve the reconstruction of the material ablation interface grid. Thus, the coordinates of the spatial grid points of the material ablation interface after reconstruction are obtained, and finally the ablation shape grid information without physical distortion and distortion at the current calculation time is obtained.

[0052] Step S1 specifically includes the following steps:

[0053] Step S11, define the normal direction of the material matrix phase plane, wherein the normal direction of the material matrix phase plane is the z coordinate direction. Before material ablation occurs, the fiber and the surrounding matrix will form an initial plane, and the ablation direction of the matrix will always remain parallel to the matrix plane, that is, the material matrix phase plane is determined and not arbitrary.

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

[0055] Step S13, based on the plane grid, according to the set grid reconstruction z-direction spacing ΔZj1 (ΔZj1>ΔZ1), where ΔZ1 is the first layer grid z-direction spacing, starting from the first layer to the last layer (ns layer), take Zk=Zk-1+ΔZj1, k=1,2,3,…,ns, respectively, take Zk value as the interpolation target height, for each column (1,2,3,…,nr) of grid points with the same sequence number as the current layer number, based on the coordinate values ​​of the grid points with corresponding numbers in the current column and the current layer and the coordinate values ​​of the original grid points, interpolation update is performed, so that all radial grid lines of the ablation interface grid are parallel to the substrate plane, and the ablation interface grid after "horizontalization" processing is obtained. Reference Figure 3 As shown, it is a schematic diagram of the ablation interface grid obtained after the horizontal processing provided in this embodiment.

[0056] In this embodiment, the nr×ns plane grid obtained by step S1 or step S12 does not need to perform interpolation update on the z coordinate of the portion that is not ablated in the z direction. Therefore, in order to reduce unnecessary "interpolation update" actions and save computer resources, it is necessary to first determine the grid layer that needs to be "interpolated and updated", that is, determine the grid layer that needs to be reconstructed. Therefore, after step S1 updates the ablation interface grid points by interpolation or before step S13, the following steps are also included:

[0057] Step S121, based on the plane grid, starting from the bottom grid layer of the fiber plane grid, determine the maximum z coordinate z of the grid in the layer j,max Is it higher than the z coordinate value z corresponding to the current position of the matrix phase plane? matrix , if z j,max >z matrix , then it is the grid layer that needs to be reconstructed, and the grid layer that needs to be reconstructed is determined layer by layer from bottom to top.

[0058] In a specific embodiment, when determining the grid layers to be reconstructed layer by layer from bottom to top, the grid layers determined to be reconstructed are marked jt (t=1, 2, 3, ..., nz) in sequence.

[0059] In one embodiment, the material ablation grid evolution process is likely to result in grid line crossing. The grid after the "horizontalization" processing in step S1 will also result in grid line crossing. Therefore, after the z coordinates of all grid points are processed through the above steps S11-S13, the x, y coordinates of each layer of grid need to be judged and reconstructed and updated. The distortion judgment is the question of whether the line segments between the grid points in the plane are crossed.

[0060] In a specific embodiment, based on the horizontal grid of the ablation interface of a single cylindrical fiber, the steps of determining grid distortion and reconstructing and updating each layer of grid points are as follows:

[0061] Step S21: based on any grid layer, all grid point coordinates in the plane are numbered in counterclockwise order.

[0062] Step S22, according to the grid point sequence number i from 1 to nr-3, determine in sequence whether the grid line PiPi+1 is connected to the grid lines Pi+1Pi+2, Pi+2Pi+3, ..., Is there an intersection? If there is an intersection, go to step S23. If there is no intersection, perform grid line intersection judgment based on the next (i+1) grid point.

[0063] Step S23, if there is a mesh segment intersection, the four mesh points corresponding to the crossed mesh lines are numbered in ascending order as calculation point ①, calculation point ②, calculation point ③ and calculation point ④, and the intersection point is numbered Pc.

[0064] Step S24, respectively counting the number of grid points between calculation points ②, ③ and calculation points ①, ④ as N23 and N14;

[0065] Step S25, if N 23 ≤N 14 , all the grid points between the two grid points corresponding to the calculation points ② and ③ are horizontally moved and evenly distributed between the two grid points corresponding to the calculation points ① and ④, and the grid point closest to Pc is moved to cover the Pc point.

[0066] Step S26, on the contrary, if N 23 >N 14 , all grid points between the two grid points corresponding to calculation points ① and ④ are horizontally moved and evenly distributed between the two grid points corresponding to calculation points ② and ③, and the grid point closest to Pc is moved to point Pc.

[0067] Step S27, repeat steps S23 to S26 until the grid points are completed. Distortion judgment and reconstruction processing of grid points.

[0068] Compared with other grid reconstruction methods, the method of this embodiment pre-processes the spatial quadrilateral grid of the composite material ablation interface by "horizontalization", so that the judgment of whether the ablation interface grid is distorted only needs to be performed within the plane grid points after each layer is "horizontalized", which solves the problem of difficulty in judging the grid distortion of the composite material ablation interface under large ablation deformation conditions, and practice shows that it has high accuracy and analysis efficiency. Compared with other grid reconstruction methods, the method of this embodiment attributes the grid distortion problem that may occur in the evolution process of the composite material ablation interface to the intersection problem of line segments in the plane, and further summarizes the intersection problem into two situations for reconstruction processing respectively. It has the characteristics of high grid distortion judgment efficiency and fast distortion reconstruction processing speed, which is conducive to improving the comprehensive simulation efficiency of the composite material ablation interface grid evolution process.

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

[0070] The burnt tip phenomenon refers to the formation of a sharp point at the top of the reinforcement due to ablation, and the determination of the burnt tip phenomenon is an important step in the process of tracking the evolution of the material ablation interface morphology. It not only helps to accurately capture the changes in the geometric characteristics of the material surface, but also helps to improve the simulation accuracy and calculation efficiency. When the present embodiment performs burnt tip determination, the position of the virtual top surface is first updated, and the ablation rate of the virtual top surface is synchronously calculated in the ablation rate calculation step. The theoretical position of the top surface of the reinforcement after ablation can be determined in combination with the time step; then, based on the reconstructed coordinates of each grid point, the coordinates of the virtual top surface at the current position are determined. In fact, the coordinates of each point on the periphery of the virtual top surface can be obtained by interpolation algorithm based on the reconstructed coordinates of the grid points, and the area A of the virtual top surface at this time is determined based on the above coordinates. up , as the basis for determining the burning tip.

[0071] Specifically, the determination coefficient α of the fiber morphology evolving into a cone is predefined, and the area A of the virtual top surface is up When the area of ​​the virtual top surface is smaller than α times, the reinforcement morphology is determined to have evolved into a cone, otherwise, the reinforcement is determined to have not been burnt to a point. In some embodiments, the value of the determination coefficient α should be smaller than 1.0E-5. Figure 3The schematic diagram shows the position of the virtual top surface when the tip is not burned. Figure 4 The position of the virtual top surface in the case of burnt tip is shown.

[0072] S60, reinforcement mesh updating step, at least includes: when it is determined that the reinforcement is not burnt, taking the virtual top surface as the actual top surface of the reinforcement, and determining the updated coordinates of each grid point in the actual top surface according to the current coordinates of the virtual top surface, and forming an interface morphology mesh at the current time step; when it is determined that the reinforcement is burnt, determining the actual height of the reinforcement at the current time step, and deleting the reconstructed coordinates of all grid points exceeding the actual height to form an interface morphology mesh.

[0073] For the two different ablation situations determined in step S50, this embodiment adopts different methods to update the reinforcement mesh to ensure the mesh quality and calculation 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 morphological interface is as follows: Figure 3 As shown, the virtual top surface is used as the actual top surface of the reinforcement body, and the height is higher than the virtual top surface z up The grid points of the second morphological interface are deleted, and the coordinates of each grid point in the actual top surface are determined according to the coordinates of the virtual end surface obtained in the burn tip determination step, and the reconstructed coordinates of the undeleted grid points are further combined to form the interface morphology grid at the current time step. For the case of the reinforced body burn tip, the positional relationship between the virtual top surface and the second morphological interface is as follows: Figure 4 As shown, at this time, the top of the reinforcement has degenerated into a sharp point, and the height z of the highest point of the current second morphology interface must be matrix and the current height z of the virtual top surface up The height corresponding to the minimum radial cross-sectional area of ​​the reinforcement is calculated as the actual height z of the actual morphology of the reinforcement at the current time step. max , and in the second morphology interface, delete the reconstructed coordinates of the grid points whose height is greater than the actual height to form the interface morphology grid at the current time step.

[0074] In this embodiment, taking into account the characteristics of geometric changes in the material ablation process, especially when a sharp point is 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 grid; at the same time, by removing invalid grid points, the calculation of the number of grid points in the next time step can be further reduced, thereby achieving the purpose of improving calculation efficiency.

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

[0076] After step S60 is executed, the mesh situation of the composite material ablation morphology interface at the current time step can be obtained, and then a judgment is made as to 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 the surface thermal environment parameters are updated, and the ablation rate calculation step is re-executed, and the cycle is repeated until the evolution end time. 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 the time steps before the end of the evolution is output, and sorted according to the time step to obtain the evolution tracking result of the composite material ablation morphology interface.

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

[0078] This embodiment proposes a method for tracking the evolution of the ablation morphology interface of a composite material based on the Lagrangian method, which is combined with the ablation regression of the virtual top surface and the strategy for determining the burnt tip of the reinforcement. It greatly reduces the difficulty of determining and reconstructing non-physical distortion during the evolution of the interface mesh, solves the mesh distortion and distortion problems that may occur in the case of ablation deformation, and has the characteristics of high accuracy in morphology interface tracking and easy implementation of simulation tracking strategies. At the same time, the overall mesh calculation amount of the scheme is small, which improves the calculation efficiency.

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

[0080] Initialization module 10 is used to construct a 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 matrix ablation plane and the peripheral 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 according to the surface thermal environment parameters of the composite material;

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

[0083] A morphology reconstruction module 40 is used to perform non-physical distortion grid reconstruction on the first morphology interface formed by the spatial coordinates of all grid points, and determine the reconstructed coordinates of each grid point after reconstruction to form a second morphology interface;

[0084] The burnt tip 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, 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, it is determined that the reinforcement is burnt tip, otherwise, it is determined that the reinforcement is not burnt tip;

[0085] The reinforcement mesh updating module 60 is used to, when it is determined that the reinforcement is not burnt, use the virtual top surface as the actual top surface of the reinforcement, and determine the updated coordinates of each grid point in the actual top surface according to the coordinates of the virtual top surface, and form the interface morphology mesh at the current time step; when it is determined that the reinforcement is burnt, determine the actual height of the reinforcement at the current time step, and delete the reconstructed coordinates of all grid points exceeding the actual height to form the interface morphology 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 re-called. If the evolution end time has been reached, the interface morphology grid at each time step is output to obtain the evolution tracking result of the composite material ablation morphology interface.

[0087] In some embodiments, the initialization module 10 specifically divides the outer contour surface grid of the reinforcement body by adopting the principle that the radial grid lines are kept parallel to the ablation plane of the substrate.

[0088] In some embodiments, the ablation rate calculation module 20 specifically uses a 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 morphology reconstruction module 40 specifically adopts the principle of keeping the radial grid lines parallel to the substrate ablation plane, performs non-physical distortion grid judgment and reconstruction calculation of non-parallel grid lines on the first morphology interface, and determines the reconstruction coordinates of each grid point after reconstruction to form a second morphology interface.

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

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

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

[0093] This embodiment proposes a method for tracking the evolution of the ablation morphology interface of a composite material based on the Lagrangian method, and synergistically applies the strategy of ablation regression of the virtual top surface and determination of the burnt tip of the reinforcement, which greatly reduces the difficulty of determining and reconstructing non-physical distortion during the evolution of the interface mesh, and solves the problems of mesh distortion and distortion that may occur in the case of ablation deformation. It has the characteristics of high accuracy in morphology interface tracking and easy implementation of simulation tracking strategies. At the same time, the overall mesh calculation amount of the scheme is small, which improves the calculation efficiency.

[0094] Based on the same inventive concept, the third embodiment of the present 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 the composite material ablation morphology interface described in the first embodiment of the present disclosure.

[0095] Based on the same inventive concept, the fourth embodiment of the present disclosure provides an electronic device, comprising at least a memory and a processor, wherein a computer program is stored on the memory, and when the processor executes the computer program on the memory, the processor implements the steps of the method for tracking the evolution of the ablation morphology interface of the composite material described in the first embodiment of the present disclosure.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements 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 disclosure.

Claims

1. A method for tracking the evolution of composite material ablation morphology interface, characterized in that: include: The initialization step at least includes: constructing a physical model of the composite material, and using two two-dimensional surface meshes to characterize the matrix ablation plane and the peripheral contour surface of the reinforcement according to the size of the physical model, and setting a virtual top surface for describing the theoretical ablation position of the top of the reinforcement; The ablation rate calculation step at least comprises: calculating the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface according to the surface thermal environment parameters of the composite material; The grid point coordinate calculation step at least includes: determining the ablation direction of each of the grid points, and determining the spatial coordinates of each of the grid points at the current time step in combination with the ablation rate of the grid points; The morphology reconstruction step at least includes: performing non-physical distortion grid reconstruction on the first morphology 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 morphology interface; The burn tip determination step at least includes: 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, and determining the current area of ​​the virtual top surface according to the coordinates of the virtual top surface, and determining that the reinforcement is burnt tip when the current area is less than α times the original area of ​​the virtual top surface, otherwise, determining that the reinforcement is not burnt tip; The reinforcement mesh updating step at least includes: when it is determined that the reinforcement is not burnt, taking the virtual top surface as the actual top surface of the reinforcement, and determining the updated coordinates of each grid point in the actual top surface according to the coordinates of the virtual top surface, and forming an interface morphology mesh at the current time step; when it is determined that the reinforcement is burnt, determining the actual height of the reinforcement at the current time step, and deleting the reconstructed coordinates of all grid points exceeding the actual height to form an interface morphology mesh; The evolution tracking and output step at least includes: detecting whether the evolution end time has been reached, updating the time step and the surface thermal environment parameters if the evolution end time has not been reached, and re-executing the ablation rate calculation step, and outputting the interface morphology grid at each time step if the evolution end time has been reached to obtain the evolution tracking result of the composite material ablation morphology interface.

2. The evolution tracking method according to claim 1, characterized in that: In the initialization step, the outer contour surface grid of the reinforcement body is divided into grids based on the principle that the radial grid lines are kept parallel to the substrate ablation plane.

3. The evolution tracking method according to claim 1, characterized in that: In the ablation rate calculation step, a thermochemical ablation theory calculation method is used to calculate the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface.

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

5. The evolution tracking method according to claim 1, characterized in that: In the burn tip determination step, determining the coordinates of the virtual top surface according to the reconstructed coordinates of all the grid points includes: The coordinates of the outer periphery of the virtual top surface are determined by an interpolation algorithm from the reconstructed coordinates of all the grid points.

6. The evolution tracking method according to claim 1, characterized in that: In the reinforcement body grid updating step, determining the actual height of the reinforcement body at the current time step and deleting the reconstructed coordinates of all grid points exceeding the actual height include: Between the height of the highest point of the second morphology interface and the current height of the virtual top surface, the height corresponding to the minimum radial cross-sectional area of ​​the reinforcement is calculated as the actual height of the actual morphology of the reinforcement at the current time step, and in the second morphology interface, the reconstructed coordinates of the grid points whose heights are greater than the actual height are deleted.

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

8. A device for tracking the evolution of composite material ablation morphology interface, characterized in that: include: An initialization module is used to construct a 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 matrix ablation plane and the peripheral contour surface of the reinforcement, and a virtual top surface is set to describe the theoretical ablation position of the top of the reinforcement; an ablation rate calculation module, used to calculate the ablation rate of each grid point of the reinforcement and the ablation rate of the virtual top surface according to the surface thermal environment parameters of the composite material; A grid point coordinate calculation module, used to determine the ablation direction of each of the grid points, and determine the spatial coordinates of each of the grid points at the current time step in combination with the ablation rate of the grid points; A morphology reconstruction module, used for performing non-physical distortion grid reconstruction on the first morphology 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 morphology interface; a burn tip determination module, used for 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, and determining the current area of ​​the virtual top surface according to the coordinates of the virtual top surface, and determining that the reinforcement is burnt tip when the current area is less than α times the original area of ​​the virtual top surface, otherwise, determining that the reinforcement is not burnt tip; A reinforcement mesh updating module is used to, when it is determined that the reinforcement is not burnt, use the virtual top surface as the actual top surface of the reinforcement, and determine the updated coordinates of each grid point in the actual top surface according to the coordinates of the virtual top surface, and form an interface morphology mesh at the current time step; when it is determined that the reinforcement is burnt, determine the actual height of the reinforcement at the current time step, and delete the reconstructed coordinates of all grid points exceeding the actual height to form an interface morphology 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 re-called. If the evolution end time has been reached, the interface morphology grid at each time step is output to obtain the evolution tracking result 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 a processor, the steps of the method for tracking the evolution of the composite material ablation morphology interface according to any one of claims 1 to 7 are implemented.

10. An electronic device, comprising at least a memory and a processor, wherein a computer program is stored in the memory, wherein: The processor implements the steps of the method for tracking the evolution of the composite material ablation morphology interface according to any one of claims 1 to 7 when executing the computer program on the memory.

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