A method, device, equipment, medium and product for identifying surface damage of ablative material

Abstract

This application discloses a method, apparatus, device, medium, and product for identifying surface damage of ablation materials, relating to the field of ablation materials. The method includes: acquiring the temperature time-domain history of the bottom surface of the ablation material to be identified within a preset time period; establishing a damage identification model in finite element software based on the shape of the ablation material when undamaged, and setting the estimated damage on a moving temperature interface with a fixed temperature in the damage identification model; solving for the parameter values ​​of the estimated damage based on the temperature time-domain history and the heat transfer control equation of the damage identification model in the region below the moving temperature interface, to obtain the parameter values ​​of the surface damage parameters of the ablation material to be identified. This application can improve the accuracy and efficiency of identifying surface damage of ablation materials.

Description

Technical Field

[0001] This application relates to the field of ablation material damage identification, and in particular to a method, apparatus, equipment, medium, and product for identifying surface damage of ablation materials. Background Technology

[0002] Thermal protection systems, as a key component of hypersonic vehicles, protect the vehicle from severe aerodynamic heating during high-speed flight through the atmosphere. However, damage to these systems can occur due to impacts from space debris, vibrations, or oxidation, potentially leading to safety incidents.

[0003] Due to the harsh aerodynamic and thermal environment encountered by spacecraft during atmospheric flight, directly detecting damage to the surface of thermal protection systems using sensors placed on the outer surface is difficult. In related technical fields, a heat flow identification model is established to solve for the heat flow on the surface of ablated materials. This surface heat flow is then used to establish a damage identification model to identify surface damage in ablated materials. In this method, the estimated damage is established on the upper surface of the damage identification model, and then the damage parameters of the estimated damage are solved to obtain the surface damage parameters of the ablated material. However, ablation involves complex physicochemical changes, greatly increasing the nonlinearity between surface excitation and bottom surface stability response. Furthermore, the heat transfer control equations for ablation are much more complex than those for ordinary heat transfer. In finite element analysis, under the same model size and mesh density, the computation time for ablation is several times longer than that for ordinary heat transfer, resulting in low accuracy and efficiency in obtaining the damage parameters. Summary of the Invention

[0004] The purpose of this application is to provide a method, apparatus, equipment, medium, and product for identifying surface damage of ablation materials, which can improve the accuracy and efficiency of identifying surface damage of ablation materials.

[0005] To achieve the above objectives, this application provides the following solution:

[0006] In a first aspect, this application provides a method for identifying surface damage of ablation materials, including:

[0007] Obtain the temperature time-domain history of the bottom surface of the ablation material to be identified within a preset time period;

[0008] A damage identification model is established in finite element software based on the shape of the ablation material to be identified when it is undamaged, and the estimated damage is set on a moving temperature interface with a fixed temperature in the damage identification model; wherein, the shape includes the width and thickness of the ablation material to be identified, the material property parameters of the damage identification model are the material property parameters of the ablation material to be identified when it has not undergone pyrolysis, and the fixed temperature is the pyrolysis start temperature of the ablation material to be identified;

[0009] The parameter values ​​of the predicted damage are solved by the heat transfer control equation of the damage identification model in the region below the moving temperature interface, based on the temperature time-domain history and the damage identification model, to obtain the parameter values ​​of the surface damage parameters of the ablation material to be identified; wherein, the surface damage parameters include the damage center point, damage width and damage depth.

[0010] Furthermore, the expression for the heat transfer control equation of the damage identification model in the region below the moving temperature interface is as follows:

[0011]

[0012] Where ρ, C, and k are the density, specific heat, and thermal conductivity of the ablation material to be identified, respectively, and W(x,y,t) is the two-dimensional temperature field of the ablation material to be identified with width x and thickness y at time t.

[0013] Further, based on the temperature time-domain history and the heat transfer control equation of the damage identification model in the region below the moving temperature interface, the parameter values ​​of the predicted damage are solved to obtain the parameter values ​​of the surface damage parameters of the ablation material to be identified, including:

[0014] Initialize the parameter values ​​of the damage center point, damage width, damage depth, interface position, and temperature field of the ablation material to be identified;

[0015] The temperature difference between the upper and lower surfaces of the damage identification model is corrected using the time-domain histories of the damage center point, damage width, damage depth, and interface position parameters. An objective function is constructed with the goal of minimizing the corrected value. The temperature difference is the difference between the time-domain histories of the bottom surface temperature and the temperature time-domain histories.

[0016] The update formulas are determined based on the objective function, the time-domain history of the bottom surface temperature, and the corresponding sensitivity matrix. The update formulas include the update formulas for the time-domain history of the damage center point, the time-domain history of the damage width, the time-domain history of the damage depth, and the time-domain history of the interface position parameters.

[0017] The initial bottom surface temperature time-domain history of the damage identification model is calculated based on the initial temperature field of the ablation material to be identified and the heat transfer control equation of the damage identification model in the region below the moving temperature interface.

[0018] The function value of the objective function is calculated based on the initial values ​​of the time-domain history of the damage center point, the initial values ​​of the time-domain history of the damage width, the initial values ​​of the time-domain history of the damage depth, the initial time-domain history of the bottom surface temperature, and the time-domain history of the temperature.

[0019] If the function value of the objective function is less than the preset value, then the initial values ​​of the time-domain history of the damage center point, the initial value of the time-domain history of the damage width, and the initial values ​​of the time-domain history of the damage depth are determined to be the parameter values ​​of the surface damage parameters of the ablation material to be identified.

[0020] If the value of the objective function is greater than or equal to a preset value, then the initial values ​​of the time-domain history of the damage center point, the damage width, the damage depth, and the interface position parameter are updated according to the update formula until the value of the objective function meets the preset condition; wherein, the preset condition is that the difference between the values ​​of the objective function calculated in two adjacent update processes is less than a stop preset value.

[0021] Further, based on the initial temperature field of the ablation material to be identified and the heat transfer control equation of the damage identification model in the region below the moving temperature interface, the initial bottom surface temperature time-domain history of the damage identification model is calculated, including:

[0022] The preset duration is divided into multiple time steps;

[0023] A coordinate system is constructed with the lower left corner of the damage recognition model as the origin, the thickness direction as the y-axis, and the width direction as the x-axis. The spatial domain is uniformly divided into multiple grid nodes in the x and y directions.

[0024] The spatial domain is updated at each time step, and the position of each grid node is calculated;

[0025] The initial temperature of each grid node at the initial moment is obtained based on the initial temperature field of the ablation material to be identified.

[0026] The forward difference algorithm is used to update the time of each grid node;

[0027] The position of each grid node is updated using the center difference algorithm;

[0028] The initial temperature, updated time, updated position of each grid node, and the heat transfer control equation of the damage identification model in the region below the moving temperature interface are used to calculate the temperature of all grid nodes at all times, and the initial bottom surface temperature time-domain history of the damage identification model is obtained based on the temperature of all grid nodes at all times.

[0029] Furthermore, the sensitivity matrix includes a first sensitivity matrix, a second sensitivity matrix, a third sensitivity matrix, and a fourth sensitivity matrix, with the following expressions:

[0030]

[0031] Among them, J a Jb J c J dis(t) Let T be the first sensitivity matrix, the second sensitivity matrix, the third sensitivity matrix, and the fourth sensitivity matrix, respectively. Let a, b, c, and dis(t) be the time-domain histories of the damage center point, the damage width, the damage depth, and the interface position parameters, respectively. Let T be the transpose of the matrix. f This represents the time-domain history of the bottom surface temperature of the damage identification model.

[0032] Furthermore, the expression for the objective function is:

[0033]

[0034] Where S(a, b, c, dis(t)) is the objective function, Y is the temperature time-domain history, and α is the regularization coefficient.

[0035] Secondly, this application provides a device for identifying surface damage of ablation materials, comprising:

[0036] The data acquisition module is used to acquire the temperature time-domain history of the bottom surface of the ablation material to be identified within a preset time period;

[0037] The model building module is used to build a damage identification model in finite element software based on the shape of the ablation material to be identified when it is undamaged, and to set the estimated damage on a moving temperature interface with a fixed temperature in the damage identification model; wherein, the shape includes the width and thickness of the ablation material to be identified, the material property parameters of the damage identification model are the material property parameters of the ablation material to be identified when it has not undergone pyrolysis, and the fixed temperature is the pyrolysis start temperature of the ablation material to be identified;

[0038] The damage identification module is used to solve the parameter values ​​of the estimated damage based on the temperature time-domain history and the heat transfer control equation of the damage identification model in the region below the moving temperature interface, so as to obtain the parameter values ​​of the surface damage parameters of the ablation material to be identified; wherein, the surface damage parameters include the damage center point, damage width and damage depth.

[0039] Thirdly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method for identifying surface damage of ablation materials.

[0040] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method for identifying surface damage of ablation materials.

[0041] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method for identifying surface damage on ablated materials.

[0042] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0043] This application provides a method, apparatus, equipment, medium, and product for identifying surface damage of ablation materials. By constructing a damage identification model and setting the estimated damage on the moving temperature interface in the damage identification model, the parameter values ​​of the surface damage parameters of the ablation material to be identified are solved using the heat transfer control equation of the region below the moving temperature interface. In the solution process, the complex ablation behavior in the region above the moving temperature interface is not considered, which greatly improves the calculation speed. At the same time, only the response between the bottom surface temperature and the moving temperature interface in the linear part is considered, which improves the accuracy of surface damage identification. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is an application environment diagram of a method for identifying surface damage of ablation materials according to an embodiment of this application;

[0046] Figure 2 A flowchart illustrating a method for identifying surface damage of ablation materials according to an embodiment of this application;

[0047] Figure 3 This is a schematic diagram of a surface damage identification model for ablation materials provided in one embodiment of this application;

[0048] Figure 4 for Figure 2 A detailed flowchart illustrating the steps of the method for identifying surface damage in ablated materials;

[0049] Figure 5 A comparison diagram of surface damage identification results and actual damage of an ablation material provided in an embodiment of this application;

[0050] Figure 6 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] The surface damage identification method for ablation materials provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be set up independently, integrated into server 104, or placed in the cloud or on another server. Terminal 102 can send the temperature time-domain history of the bottom surface of the ablated material to be identified within a preset time period to server 104. After receiving the temperature time-domain history, server 104, based on the temperature time-domain history of the bottom surface of the ablated material to be identified within the preset time period and the heat transfer control equation of the damage identification model in the region below the moving temperature interface, solves for the estimated damage parameter values ​​to obtain the surface damage parameters of the ablated material to be identified. Server 104 can then feed back the obtained surface damage parameter values ​​of the ablated material to terminal 102. In addition, in some embodiments, the method for identifying surface damage of ablated materials can also be implemented by the server 104 or the terminal 102 alone. For example, the terminal 102 can directly process the temperature time-domain history of the bottom surface of the ablated material to be identified within a preset time period, or the server 104 can obtain the temperature time-domain history of the bottom surface of the ablated material to be identified within a preset time period from the data storage system and process it.

[0054] The terminal 102 can be, but is not limited to, various desktop computers, laptops, smartphones, and tablets. The server 104 can be implemented using a standalone server or a server cluster consisting of multiple servers, or it can be a cloud server.

[0055] In one exemplary embodiment, such as Figure 2 As shown, a method for identifying surface damage of ablation materials is provided. This method is executed by a computer device, specifically by a terminal or server alone, or by both a terminal and a server. In this embodiment, the method is applied to... Figure 1Taking server 104 as an example, the explanation includes the following steps 201 to 203. Wherein:

[0056] Step 201: Obtain the temperature time-domain history of the bottom surface of the ablation material to be identified within a preset time period.

[0057] Specifically, in order to obtain the temperature time-domain history that can describe the response changes in real time, the temperature time-domain history is collected by a thermocouple sensor placed on the bottom of the ablation material to be identified.

[0058] Step 202: Based on the shape of the ablation material to be identified when it is undamaged, a damage identification model is established in the finite element software, and the estimated damage is set on a moving temperature interface with a fixed temperature in the damage identification model; wherein, the shape includes the width and thickness of the ablation material to be identified, the material property parameters of the damage identification model are the material property parameters of the ablation material to be identified when it has not undergone pyrolysis, and the fixed temperature is the pyrolysis start temperature of the ablation material to be identified.

[0059] Specifically, the position of the moving temperature interface in the damage identification model changes over time. Initially, it starts from the upper surface of the damage identification model and moves along the thickness direction, with the direction perpendicular to the bottom surface being the thickness direction. Interface position parameters are defined to describe the positional change of the moving temperature interface within the damage identification model.

[0060] The predicted damage is established on the moving temperature interface and is controlled by three constant parameters: damage center point (controlling the location of the center point of the damage width), damage width (controlling the damage width), and damage depth (controlling the damage depth). The damage shape curve is generated by interpolation between the parameters damage width and damage depth. The constant parameters damage center point, damage width, and damage depth only describe the initial damage. To simulate the diffusion process of heat in the ablation material to be identified, the damage shape curve diffuses outward in the normal direction, and the diffusion distance is equal to dis(t).

[0061] The damage identification model does not participate in the calculation of the region above the moving temperature interface; therefore, it is unnecessary to calculate the heat flux on the upper surface of the damage identification model. The expression for the heat transfer control equation of the damage identification model in the region below the moving temperature interface is as follows:

[0062]

[0063] Where ρ, C, and k are the density, specific heat, and thermal conductivity of the ablation material to be identified, respectively, and W(x,y,t) is the two-dimensional temperature field of the ablation material to be identified with width x and thickness y at time t.

[0064] The bottom surface temperature of the damage identification model is entirely determined by the position and shape of the moving temperature interface, and the damage at the initial moment of the moving temperature interface is the damage to be identified, such as... Figure 3 As shown, Figure 3 The damage location control point is controlled by the damage center point, damage width, and damage depth.

[0065] Step 203: Solve the estimated damage parameter values ​​based on the temperature time-domain history and the heat transfer control equation of the damage identification model in the region below the moving temperature interface to obtain the parameter values ​​of the surface damage parameters of the ablation material to be identified; wherein, the surface damage parameters include the damage center point, damage width, and damage depth. Specifically, this includes steps 301-307:

[0066] Step 301: Initialize the parameter values ​​of the damage center point, damage width, damage depth, interface position, and temperature field of the ablation material to be identified.

[0067] Step 302: The temperature difference between the upper and lower surfaces of the damage identification model is corrected using the time-domain history of the damage center point, the time-domain history of the damage width, the time-domain history of the damage depth, and the time-domain history of the interface position parameters. An objective function is constructed with the goal of minimizing the corrected value. The temperature difference is the difference between the time-domain history of the bottom surface temperature and the time-domain history of the bottom surface temperature.

[0068] The expression for the objective function is:

[0069]

[0070] Where S(a, b, c, dis(t)) is the objective function, Y is the temperature time-domain history, T is the transpose of the matrix, and α is the regularization coefficient.

[0071] Step 303: Determine the update formulas based on the objective function, the time-domain history of the bottom surface temperature, and the corresponding sensitivity matrix. The update formulas include the update formulas for the time-domain history of the damage center point, the time-domain history of the damage width, the time-domain history of the damage depth, and the time-domain history of the interface position parameters.

[0072] The sensitivity matrix includes a first sensitivity matrix, a second sensitivity matrix, a third sensitivity matrix, and a fourth sensitivity matrix, with the following expressions:

[0073]

[0074] Among them, J a J b J c J dis(t)Let T be the first sensitivity matrix, the second sensitivity matrix, the third sensitivity matrix, and the fourth sensitivity matrix, respectively. Let a, b, c, and dis(t) be the time-domain histories of the damage center point, the damage width, the damage depth, and the interface position parameters, respectively. Let T be the transpose of the matrix. f This represents the time-domain history of the bottom surface temperature of the damage identification model.

[0075] The update formulas for the time-domain histories of the damage center point, damage width, damage depth, and interface position parameters are as follows:

[0076]

[0077]

[0078] Among them, a k+1 For the time-domain history of the damage center point after the (k+1)th update, a k Let I be the time-domain history of the damage center point after the k-th update, where I is the identity matrix and b is the time-domain history of the damage center point. k+1 For the time-domain history of the damage width after the (k+1)th update, b k For the time-domain history of the damage width after the k-th update, c k+1 For the time-domain history of the damage depth after the (k+1)th update, c k Let [dis(t)] be the time-domain history of the damage depth after the k-th update. k+1 Let [dis(t)] be the time-domain history of the interface position parameters after the (k+1)th update. k This represents the time-domain history of the interface position parameters after the kth update.

[0079] Step 304: Calculate the initial bottom surface temperature time-domain history of the damage identification model based on the initial temperature field of the ablation material to be identified and the heat transfer control equation of the damage identification model in the region below the moving temperature interface. Specifically, this includes steps 31-37:

[0080] Step 31: Divide the preset duration into multiple time steps.

[0081] Specifically, using Δt as the time interval, the preset duration t of the temperature time-domain history collected in step 201 is... total Divided into S time steps, its expression is:

[0082]

[0083] Step 32: Construct a coordinate system with the lower left corner of the damage recognition model as the origin, the thickness direction as the y-axis, and the width direction as the x-axis, as follows: Figure 3As shown, the spatial domain is uniformly divided into multiple grid nodes in the x and y directions. In the x direction, the length of each grid is Δx; in the y direction, the length of each grid is Δy.

[0084] Since the parameter values ​​of the damage center point, damage width, damage depth, interface position, and temperature field of the ablation material to be identified were initialized in step 301, the position and shape of the moving temperature interface are determined, denoted as Interface(x,t). Therefore, the spatial discretization formula is:

[0085]

[0086]

[0087] Where N and M are the number of grids in the x and y directions, respectively, and x total The thickness of the damage identification model is given by the temperature field at each grid node. i is the index in the x-direction, j is the index in the y-direction, n is the time step index, i = 0, 1, 2…N, j = 0, 1, 2…M, n = 0, 1, 2…S.

[0088] Step 33: Update the spatial domain at each time step and calculate the position of each grid node.

[0089] Step 34: Obtain the initial temperature of each grid node at the initial moment based on the initial temperature field of the ablation material to be identified.

[0090] Step 35: Update the time of each grid node using the forward difference algorithm.

[0091] Specifically, the discrete-time derivative is obtained using the forward difference algorithm:

[0092]

[0093] Among them, W i,j n =W(i*Δx,j*Δy(i*Δx,n*Δt),n*Δt).

[0094] Step 36: Update the position of each grid node using the central difference algorithm.

[0095] Specifically, the second-order spatial derivative is discretized using the central difference algorithm:

[0096]

[0097] Step 37: Calculate the temperature of all grid nodes at all times using the initial temperature, updated time, updated position of each grid node, and the heat transfer control equation of the damage identification model in the region below the moving temperature interface. Obtain the time-domain history of the initial bottom surface temperature of the damage identification model based on the temperature of all grid nodes at all times.

[0098] Substituting formulas (15) and (16) into formula (1), we get:

[0099]

[0100] Rearranging the terms of formula (17) yields:

[0101]

[0102] Discrete boundary conditions:

[0103] Given that the moving temperature interface has a moving boundary with a fixed temperature, and is represented by the function Interface(x,t), then the temperature on the moving boundary is expressed as:

[0104] W(x,Interface(x,t),t)=T fix (19);

[0105] Among them, T fix The pyrolysis start temperature of the ablation material to be identified.

[0106] The base of the damage identification model is an adiabatic boundary with a normal temperature derivative of zero.

[0107]

[0108] Transform the boundary conditions of the adiabatic and moving boundaries into discrete form:

[0109] W i，M =T fix (twenty one);

[0110] W i，1 =W i，0 (twenty two);

[0111] Among them, W i，M For the temperature field of the damage identification model at x = i*Δx and y = M*Δy, W i，1 For the temperature field of the damage identification model at x = i*Δx and y = 1*Δy, W i，0 The temperature field of the damage identification model at x = i*Δx, y = 0.

[0112] If the initial temperature of the ablation material to be identified is set to room temperature, and the initial temperature field does not cover the boundary conditions, then:

[0113] W 0 =W initial (twenty three);

[0114] Among them, W 0 W represents the initial temperature of the ablation material to be identified. initial Room temperature.

[0115] Solving equation (18), when n=0, all the right-hand side of equation (18) is known, so the temperature at any point in the temperature field at time n=1 can be calculated. By traversing all grid nodes, the temperature field at time n=1 can be obtained. By traversing all grid nodes at all times, the time-domain history of the entire temperature field can be obtained, thus obtaining the initial bottom surface temperature time-domain history of the damage identification model.

[0116] Step 305: Calculate the function value of the objective function based on the initial value of the time-domain history of the damage center point, the initial value of the time-domain history of the damage width, the initial value of the time-domain history of the damage depth, the time-domain history of the initial bottom surface temperature, and the time-domain history of the temperature.

[0117] Substitute the initial values ​​of the time-domain history of the damage center point, the initial values ​​of the time-domain history of the damage width, the initial values ​​of the time-domain history of the damage depth, the time-domain history of the initial bottom surface temperature, and the time-domain history of the temperature into formula (2) to obtain the function value of the objective function. Then, determine whether the function value of the objective function meets the stopping criterion. The stopping criterion includes a stopping condition and a preset condition. The stopping condition is that the function value of the objective function is less than the preset value. The preset condition is that the difference between the function values ​​of the objective function calculated in two adjacent update processes is less than the stopping preset value.

[0118] If the stopping criterion is met, proceed to step 306; if the stopping criterion is not met, proceed to step 307.

[0119] Specifically, after calculating the function value of the objective function using the initial values ​​of the time-domain history of the damage center point, the initial values ​​of the time-domain history of the damage width, the initial values ​​of the time-domain history of the damage depth, and the time-domain history of the initial bottom surface temperature, the stopping criterion is the stopping condition. The function value of the objective function is judged using the stopping condition. If the stopping condition is not met, i.e., the stopping criterion is not met, then step 307 is executed.

[0120] Step 306: If the function value of the objective function is less than a preset value, then the initial values ​​of the time-domain history of the damage center point, the initial value of the time-domain history of the damage width, and the initial values ​​of the time-domain history of the damage depth are determined to be the parameter values ​​of the surface damage parameters of the ablation material to be identified.

[0121] The expression for the stopping condition is:

[0122] S(a,b,c,dis(t))<0.1(24).

[0123] Step 307: If the function value of the objective function is greater than or equal to a preset value, then the initial values ​​of the time-domain history of the damage center point, the damage width, the damage depth, and the interface position parameter are updated according to the update formula until the function value of the objective function meets the preset condition.

[0124] In step 307, the function value of the objective function is calculated using the updated time-domain history of the damage center point, the updated time-domain history of the damage width, the updated time-domain history of the damage depth, and the updated time-domain history of the interface position parameters. At this point, the stopping criterion is a preset condition, and the function value of the objective function is judged using the preset condition.

[0125] The expression for the preset condition is:

[0126] |S(a k+1 ,b k+1 ,c k+1 [dis(t)] k+1 )-S(a k ,b k ,c k [dis(t)] k )|≤1% (25).

[0127] In an exemplary embodiment, the process from obtaining the temperature time-domain history of the bottom surface of the ablation material to identify the damage treatment process on the upper surface of the ablation material is as follows: Figure 4 As shown, reading the temperature signal obtains the time-domain temperature history of the bottom surface of the ablation material to be identified within a preset time period. A damage identification model is established. The estimated damage is set in the moving temperature interface of the damage identification model. An initial guess is given, which initializes the parameter values ​​of the damage center point, damage width, damage depth, interface position, and the temperature field of the ablation material to be identified. The bottom surface temperature is calculated, which calculates the time-domain temperature history of the bottom surface of the ablation material to be identified. The function value of the objective function is calculated, and it is determined whether the function value of the objective function meets the stopping criterion. At this time, the stopping criterion is the stopping condition. If yes, the surface damage parameter value is output. If no, each sensitivity matrix is ​​calculated, including the first sensitivity matrix, the second sensitivity matrix, the third sensitivity matrix, and the fourth sensitivity matrix. The estimated value of the surface damage parameter is calculated. Based on the estimated value of the surface damage parameter, the surface damage parameter value in the damage identification model is updated, that is, the estimated damage parameter value on the moving temperature interface. Based on this, the bottom surface temperature is recalculated until the objective function meets the stopping criterion. At this time, the stopping criterion is the preset condition.

[0128] A study on surface damage identification was conducted using carbonized ablation materials as an example. An ablation material model with a width of 100 mm and a thickness of 20 mm was constructed. A 40 mm wide and 10 mm deep damage was found at the center of the upper surface of the model. A coordinate system was constructed with the lower left corner of the model as the origin, the thickness direction as the y-axis, and the width direction as the x-axis. Thermocouple sensors were placed at positions (0,0), (50,0), and (100,0) on the bottom surface of the model. An arbitrary heat flux load was applied to the upper surface of the model. The temperature time-domain history was collected using temperature sensors, and the surface damage identification method for ablation materials proposed in this application was used to identify the surface damage of the model. Figure 5 As shown, the damage identified using the method in this application matches the actual damage very closely, demonstrating the effectiveness of the method in this application.

[0129] Based on the same inventive concept, this application also provides an ablation material surface damage identification device for implementing the ablation material surface damage identification method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the ablation material surface damage identification device provided below can be found in the limitations of the ablation material surface damage identification method described above, and will not be repeated here.

[0130] In one exemplary embodiment, an ablation material surface damage identification device is provided, comprising:

[0131] The data acquisition module is used to acquire the temperature time-domain history of the bottom surface of the ablation material to be identified within a preset time period.

[0132] The model building module is used to build a damage identification model in finite element software based on the shape of the ablation material to be identified when it is undamaged, and to set the estimated damage on a moving temperature interface with a fixed temperature in the damage identification model; wherein, the shape includes the width and thickness of the ablation material to be identified, the material property parameters of the damage identification model are the material property parameters of the ablation material to be identified when it has not undergone pyrolysis, and the fixed temperature is the pyrolysis start temperature of the ablation material to be identified.

[0133] The damage identification module is used to solve the parameter values ​​of the estimated damage based on the temperature time-domain history and the heat transfer control equation of the damage identification model in the region below the moving temperature interface, so as to obtain the parameter values ​​of the surface damage parameters of the ablation material to be identified; wherein, the surface damage parameters include the damage center point, damage width and damage depth.

[0134] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 6As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program implements a method for identifying surface damage on ablated materials.

[0135] Those skilled in the art will understand that Figure 6 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0136] In one exemplary embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0137] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0138] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0139] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0140] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0141] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0142] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for identifying surface damage in ablation materials, characterized in that, The method for identifying surface damage in ablation materials includes: Obtain the temperature time-domain history of the bottom surface of the ablation material to be identified within a preset time period; A damage identification model is established in finite element software based on the shape of the ablation material to be identified when it is undamaged, and the estimated damage is set on a moving temperature interface with a fixed temperature in the damage identification model; wherein, the shape includes the width and thickness of the ablation material to be identified, the material property parameters of the damage identification model are the material property parameters of the ablation material to be identified when it has not undergone pyrolysis, and the fixed temperature is the pyrolysis start temperature of the ablation material to be identified; The parameter values ​​of the predicted damage are solved based on the temperature time-domain history and the heat transfer control equation of the damage identification model in the region below the moving temperature interface to obtain the parameter values ​​of the surface damage parameters of the ablation material to be identified; specifically, this includes: initializing the parameter values ​​of the damage center point, the damage width, the damage depth, the interface position parameters, and the temperature field of the ablation material to be identified. The temperature difference between the upper and lower surfaces of the damage identification model is corrected using the time-domain histories of the damage center point, damage width, damage depth, and interface position parameters. An objective function is constructed with the goal of minimizing the corrected value. The temperature difference is the difference between the time-domain histories of the bottom surface temperature and the temperature time-domain histories. The update formulas are determined based on the objective function, the time-domain history of the bottom surface temperature, and the corresponding sensitivity matrix. These update formulas include those for the time-domain history of the damage center point, the damage width, the damage depth, and the interface position parameters. The expressions are as follows: Among them, a k+1 This is the time-domain history of the damage center point after the (k+1)th update. and These are the first, second, third, and fourth sensitivity matrices after the k-th update, respectively, where Y represents the temperature time-domain history, and T... f k The bottom surface temperature time-domain history of the damage identification model after the k-th update is given, where α is the regularization coefficient. k Let I be the time-domain history of the damage center point after the k-th update, where I is the identity matrix and b is the time-domain history of the damage center point. k+1 For the time-domain history of the damage width after the (k+1)th update, b k For the time-domain history of the damage width after the k-th update, c k+1 For the time-domain history of the damage depth after the (k+1)th update, c k Let [dis(t)] be the time-domain history of the damage depth after the k-th update. k+1 Let [dis(t)] be the time-domain history of the interface position parameters after the (k+1)th update. k The time-domain history of the interface position parameters after the k-th update; The initial bottom surface temperature time-domain history of the damage identification model is calculated based on the initial temperature field of the ablation material to be identified and the heat transfer control equation of the damage identification model in the region below the moving temperature interface. The function value of the objective function is calculated based on the initial values ​​of the time-domain history of the damage center point, the initial values ​​of the time-domain history of the damage width, the initial values ​​of the time-domain history of the damage depth, the initial time-domain history of the bottom surface temperature, and the time-domain history of the temperature. If the function value of the objective function is less than the preset value, then the initial values ​​of the time-domain history of the damage center point, the initial value of the time-domain history of the damage width, and the initial values ​​of the time-domain history of the damage depth are determined to be the parameter values ​​of the surface damage parameters of the ablation material to be identified. If the value of the objective function is greater than or equal to a preset value, then the initial values ​​of the time-domain history of the damage center point, the damage width, the damage depth, and the interface position parameters are updated according to the update formula until the value of the objective function meets the preset condition. The preset condition is that the difference between the function values ​​of the objective function calculated in two adjacent update processes is less than a stop preset value. The surface damage parameters include the damage center point, the damage width, and the damage depth.

2. The method for identifying surface damage of ablation materials according to claim 1, characterized in that, The expression for the heat transfer control equation of the damage identification model in the region below the moving temperature interface is as follows: Where ρ, C, and k are the density, specific heat, and thermal conductivity of the ablation material to be identified, respectively, and W(x,y,t) is the two-dimensional temperature field of the ablation material with width x and thickness y at time t.

3. The method for identifying surface damage of ablation materials according to claim 2, characterized in that, The initial bottom surface temperature time-domain history of the damage identification model is calculated based on the initial temperature field of the ablation material to be identified and the heat transfer control equation of the damage identification model in the region below the moving temperature interface, including: The preset duration is divided into multiple time steps; A coordinate system is constructed with the lower left corner of the damage recognition model as the origin, the thickness direction as the y-axis, and the width direction as the x-axis. The spatial domain is uniformly divided into multiple grid nodes in the x and y directions. The spatial domain is updated at each time step, and the position of each grid node is calculated; The initial temperature of each grid node at the initial moment is obtained based on the initial temperature field of the ablation material to be identified. The forward difference algorithm is used to update the time of each grid node; The position of each grid node is updated using the center difference algorithm; The initial temperature, updated time, updated position of each grid node, and the heat transfer control equation of the damage identification model in the region below the moving temperature interface are used to calculate the temperature of all grid nodes at all times, and the initial bottom surface temperature time-domain history of the damage identification model is obtained based on the temperature of all grid nodes at all times.

4. The method for identifying surface damage of ablation materials according to claim 2, characterized in that, The sensitivity matrix includes a first sensitivity matrix, a second sensitivity matrix, a third sensitivity matrix, and a fourth sensitivity matrix, with the following expressions: Among them, J a J b J c J dis(t) Let T be the first sensitivity matrix, the second sensitivity matrix, the third sensitivity matrix, and the fourth sensitivity matrix, respectively. Let a, b, c, and dis(t) be the time-domain histories of the damage center point, the damage width, the damage depth, and the interface position parameters, respectively. Let T be the transpose of the matrix. f This represents the time-domain history of the bottom surface temperature of the damage identification model.

5. The method for identifying surface damage of ablation materials according to claim 4, characterized in that, The expression for the objective function is: Where S(a, b, c, dis(t)) is the objective function, Y is the temperature time-domain history, and α is the regularization coefficient.

6. A device for identifying surface damage of ablation materials, characterized in that, The ablation material surface damage identification device includes: The data acquisition module is used to acquire the temperature time-domain history of the bottom surface of the ablation material to be identified within a preset time period; The model building module is used to build a damage identification model in finite element software based on the shape of the ablation material to be identified when it is undamaged, and to set the estimated damage on a moving temperature interface with a fixed temperature in the damage identification model; wherein, the shape includes the width and thickness of the ablation material to be identified, the material property parameters of the damage identification model are the material property parameters of the ablation material to be identified when it has not undergone pyrolysis, and the fixed temperature is the pyrolysis start temperature of the ablation material to be identified; The damage identification module is used to solve the parameter values ​​of the estimated damage based on the temperature time-domain history and the heat transfer control equation of the damage identification model in the region below the moving temperature interface, so as to obtain the parameter values ​​of the surface damage parameters of the ablation material to be identified; specifically, it includes an initialization module, which is used to initialize the parameter values ​​of the damage center point, the damage width, the damage depth, the interface position parameter, and the temperature field of the ablation material to be identified. The objective function construction module is used to correct the temperature difference between the upper and lower surfaces of the damage identification model using the time-domain histories of the damage center point, damage width, damage depth, and interface position parameters, and constructs an objective function with the goal of minimizing the corrected value; wherein, the temperature difference is the difference between the time-domain histories of the bottom surface temperature and the temperature time-domain histories. The update module is used to determine update formulas based on the objective function, the time-domain history of the bottom surface temperature, and the corresponding sensitivity matrix. The update formulas include those for the time-domain history of the damage center point, the damage width, the damage depth, and the interface position parameters, with the following expressions: Among them, a k+1 This is the time-domain history of the damage center point after the (k+1)th update. and These are the first, second, third, and fourth sensitivity matrices after the k-th update, respectively, where Y represents the temperature time-domain history, and T... k f The bottom surface temperature time-domain history of the damage identification model after the k-th update is given, where α is the regularization coefficient. k Let I be the time-domain history of the damage center point after the k-th update, where I is the identity matrix and b is the time-domain history of the damage center point. k+1 For the time-domain history of the damage width after the (k+1)th update, b k For the time-domain history of the damage width after the k-th update, c k+1 For the time-domain history of the damage depth after the (k+1)th update, c k Let [dis(t)] be the time-domain history of the damage depth after the k-th update. k+1 Let [dis(t)] be the time-domain history of the interface position parameters after the (k+1)th update. k The time-domain history of the interface position parameters after the k-th update; The first calculation module is used to calculate the time-domain history of the initial bottom surface temperature of the damage identification model based on the initial temperature field of the ablation material to be identified and the heat transfer control equation of the damage identification model in the region below the moving temperature interface. The objective function calculation module is used to calculate the function value of the objective function based on the initial value of the time-domain history of the damage center point, the initial value of the time-domain history of the damage width, the initial value of the time-domain history of the damage depth, the time-domain history of the initial bottom surface temperature, and the time-domain history of the temperature. The first determining module is used to determine the initial values ​​of the time-domain history of the damage center point, the initial value of the time-domain history of the damage width, and the initial value of the time-domain history of the damage depth as the parameter values ​​of the surface damage parameters of the ablation material to be identified if the function value of the objective function is less than a preset value. The second determining module is used to update the initial values ​​of the time-domain history of the damage center point, the initial value of the time-domain history of the damage width, the initial value of the time-domain history of the damage depth, and the initial value of the time-domain history of the interface position parameters according to the update formula if the function value of the objective function is greater than or equal to a preset value, until the function value of the objective function meets the preset condition; wherein, the preset condition is that the difference between the function values ​​of the objective function calculated in two adjacent update processes is less than a stop preset value, and the surface damage parameters include the damage center point, the damage width, and the damage depth.

7. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the ablation material surface damage identification method according to any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for identifying surface damage of ablation materials as described in any one of claims 1-5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for identifying surface damage of ablation materials as described in any one of claims 1-5.

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