Composite solid propellant life prediction method, device, medium and equipment
By embedding the aging rate equation into the ABAQUS software and combining the UMAT and UVARM subroutines, the mechanical property changes of composite solid propellants are dynamically simulated, solving the problem of inaccurate lifetime prediction of composite solid propellants and achieving more accurate lifetime prediction and safety assessment.
Patent Information
- Application Number
- CN202510973901.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-15
- Publication Date
- 2025-10-28
AI Technical Summary
The existing technology for predicting the lifespan of composite solid propellants is inaccurate because existing simulation models fail to effectively characterize the dynamic decay characteristics of key mechanical properties such as propellant modulus and strength over aging time.
The aging rate equation is embedded in the UMAT subroutine of ABAQUS software to establish the time-varying relationship between mechanical performance characterization data and aging time. The target integration point data is obtained through the UVARM subroutine to calculate the safety factor and predict the life.
It improves the accuracy of composite solid propellant lifetime prediction, dynamically reflects the impact of the aging process, and ensures that the safety factor calculation takes into account the real-time coupling relationship between the material's load-bearing capacity and the structural stress state during the aging process.
Smart Images
Figure CN120850671A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solid rocket engine technology, and in particular to a method, apparatus, medium and equipment for predicting the lifetime of composite solid propellants. Background Technology
[0002] Solid propellants are characterized by their ability to be ready for use after a single processing, and they are destroyed when they age to the point of failure. Premature destruction can cause huge economic losses, so people hope that the service life of propellants can be as long as possible; however, if destruction is delayed, it can cause engine loss of control or even explosion during flight, resulting in unimaginable safety accidents and endangering personal lives. During long-term storage, the performance of composite solid propellants will gradually change due to various factors, eventually failing to meet the usage indicators and losing their value. This phenomenon is called the aging of composite solid propellants.
[0003] The bottleneck in the current technology for predicting the lifespan of composite solid propellants is that existing simulation models mostly use fixed mechanical parameters, which cannot characterize the dynamic decay characteristics of key mechanical properties such as propellant modulus and strength over aging time. Therefore, existing technologies lead to inaccurate predictions of the lifespan of composite solid propellants. Summary of the Invention
[0004] Therefore, it is necessary to provide a method, apparatus, medium, and equipment for predicting the lifespan of composite solid propellants to address the aforementioned technical problems.
[0005] The following technical solution is adopted in this specification: This specification provides a method for predicting the lifetime of composite solid propellants, including: Obtain mechanical property characterization data of composite solid propellants, and determine the aging rate equation based on the mechanical property characterization data; An aging rate equation is embedded in the UMAT subroutine of the ABAQUS software to establish the time-varying relationship between mechanical performance characterization data and aging time; the UMAT subroutine is used to simulate the time-varying characteristics of the mechanical performance characterization data of composite solid propellants over time. The UVARM subroutine of the ABAQUS software is used to obtain the data of the composite solid propellant under test at the target integration point, and the safety factor of the composite solid propellant under test is obtained by calculating the data of the target integration point through the time-varying characteristic relationship. The UVARM subroutine is used to solve the safety factor of the composite solid propellant. The data of the target integration point includes stress, strain, displacement, temperature field and cumulative time. Based on the safety factor of the composite solid propellant to be tested, the estimated lifetime of the composite solid propellant to be tested is determined.
[0006] Optionally, the mechanical property characterization data includes tensile strength aging data and elastic modulus aging data, and the aging rate equations include tensile strength decay equations and elastic modulus decay equations. The aging rate equation is determined based on mechanical property characterization data, specifically including: Based on the aging data of tensile strength and elastic modulus, respectively, the preset mathematical models were fitted using the least squares method to determine the data of temperature-tensile property change rate and temperature-elastic property change rate, respectively. Based on the temperature-tensile property rate of change data and the temperature-elastic property rate of change data, the linear equations corresponding to the Arrhenius equation were fitted using the least squares method to determine the tensile strength decay equation and the elastic modulus decay equation, respectively.
[0007] Optionally, the time-varying feature relationship is updated in real time; The method for real-time updating of time-varying feature relationships is as follows: The elastic modulus decay equation is invoked based on the time variable of the current calculation step to calculate the modulus decay, update the elastic modulus, and correct the material stiffness matrix through the Jacobian matrix to update the time-varying characteristic relationship.
[0008] Optionally, the safety factor of the composite solid propellant to be tested includes the maximum elongation safety factor, the tensile strength safety factor, and the dewetting damage safety factor; The formula for calculating the maximum elongation safety factor is: in, This represents the safety factor for maximum elongation. This indicates the maximum elongation of the propellant after aging. This indicates the actual elongation rate under the current operating conditions; The formula for calculating the tensile strength safety factor is: in, This represents the safety factor for tensile strength. Indicates the tensile strength of the propellant after aging. This indicates the actual stress under the current operating conditions; The formula for calculating the safety factor for dehumidification damage is: in, Indicates the safety factor for dehumidification damage. Indicates the initial porosity of the propellant. This indicates the porosity under the current operating conditions. This indicates the actual strain under the current operating conditions. Represents the natural constant.
[0009] Optionally, a constitutive model of composite solid propellant materials is applied in the UMAT subroutine; The constitutive model of composite solid propellant materials is a custom material model used to describe the mechanical behavior of composite solid propellants.
[0010] Optionally, the method further includes: The UVARM subroutine is used to map the safety factor to field variables, and a three-dimensional damage distribution cloud map is generated in the ABAQUS software post-processing.
[0011] This specification provides a composite solid propellant lifetime prediction device, comprising: The data acquisition module is specifically used to acquire mechanical property characterization data of composite solid propellants and determine the aging rate equation based on the mechanical property characterization data. The data processing module is specifically used to embed the aging rate equation into the UMAT subroutine of the ABAQUS software to establish the time-varying relationship between mechanical performance characterization data and aging time. The UMAT subroutine is used to simulate the time-varying characteristics of the mechanical performance characterization data of the composite solid propellant over time. The UVARM subroutine of the ABAQUS software acquires data of the composite solid propellant under test at the target integration point, and calculates the safety factor of the composite solid propellant under test using the time-varying characteristic relationship. The UVARM subroutine is used to solve for the safety factor of the composite solid propellant; the data at the target integration point includes stress, strain, displacement, temperature field, and cumulative time. The life prediction module is specifically used to determine the life prediction value of the composite solid propellant under test based on the safety factor of the composite solid propellant under test.
[0012] This specification provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for predicting the lifetime of composite solid propellants.
[0013] This specification 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 program to implement the above-described composite solid propellant lifetime prediction method.
[0014] The above-mentioned technical solutions adopted in this specification can achieve the following beneficial effects: In the composite solid propellant lifetime prediction method provided in this specification, by establishing a time-varying characteristic relationship between mechanical property characterization data and aging time, lifetime prediction is based on the physical mechanism of material aging rather than simple empirical extrapolation. The aging rate equation is embedded in the ABAQUS UMAT subroutine, so that the mechanical behavior (constitutive relation) of the material can dynamically and accurately reflect the influence of the aging process, thereby improving the accuracy of composite solid propellant lifetime prediction.
[0015] Another bottleneck in the current technology for predicting the lifespan of composite solid propellants is that conventional safety factor calculations are based on initial mechanical properties and do not consider the real-time coupling relationship between material load-bearing capacity and structural stress state during aging. To address this issue, this invention combines dynamic performance data with propellant data at the target integration point to calculate the current safety factor and the final lifespan estimate, thereby effectively assessing the propellant's operational safety and lifespan. By calculating the safety factor of the composite solid propellant under test using time-varying characteristic relationships from the target integration point data, including stress, strain, displacement, temperature field, and cumulative time, the accuracy of composite solid propellant lifespan prediction can be further improved. Attached Figure Description
[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0017] Figure 1 This document provides a schematic flowchart of a method for predicting the lifetime of a composite solid propellant. Figure 2 A schematic diagram of the test specimen and fixture designed for propellants; Figure 3 This is a schematic diagram of a composite solid propellant lifetime prediction device provided in this specification; Figure 4 This specification provides a schematic diagram of a computer device for implementing a method for predicting the lifetime of composite solid propellants. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of this specification clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without creative effort are within the scope of protection of this application.
[0019] The existing methods for predicting the aging life of mechanical properties are as follows: 1. Geometric Modeling and Mesh Generation: Based on the actual size and shape of the propellant, construct a geometric model and perform reasonable mesh generation.
[0020] 2. Load and Boundary Condition Application: Various loads and boundary conditions are applied to the geometric model, including self-weight and curing cooling. The application of these loads needs to be combined with actual working conditions to ensure that the simulation results match the actual situation.
[0021] 3. Finite Element Analysis: Using the finite element analysis method, the stress and strain distribution under different working conditions is calculated. Finite element analysis can provide detailed mechanical property data, providing a basis for subsequent life prediction.
[0022] 4. Uniaxial constant-velocity tensile test: For propellants, the specimen and fixture are designed according to the national standard "QJ 924-85 Uniaxial tensile test method for composite solid propellants", such as... Figure 2 As shown, Figure 2 This diagram shows the specimen and fixture designed for the propellant. Uniaxial constant-speed tensile tests were conducted on the propellant samples using an electronic universal testing machine at a test temperature of 25℃±2℃. The tensile speed during the constant-speed tensile test was 100 mm / min. The maximum elongation of the propellant specimen was obtained experimentally. initial modulus and tensile strength The data.
[0023] 5. Lifetime prediction: Lifetime prediction methods are usually based on aging models such as the Arrhenius equation, which predict the remaining life of the propellant by analyzing the changes in mechanical properties over time.
[0024] Common logarithmic, linear, and exponential models are as follows: (1) (2) (3) In the formula, Indicates time Corresponding performance; Indicates the initial performance value (usually a constant); This represents the constant representing the rate of change of performance in relation to temperature; This represents the aging time, expressed in days (d). Exponential models are generally used to predict propellant performance.
[0025] Performance change rate constant With thermodynamic temperature The relevant Arrhenius equation is as follows: (4) in, Represents the frequency factor; It represents the apparent activation energy, with units of joules per mole (J / mol). This represents the molar gas constant, with units of joules per Kelvin [J / (K·mol)]. The unit is Kelvin (K). Represents the natural constant.
[0026] When calculating the performance change rate constant K, for equation (1), let... X = logt , Y = P , a = P 0 , b = K For the linear model in equation (2), let , , a = P 0 , b = K For the exponential model in equation (3), let... X = t , Y = lnP , a = lnP 0 , b = -K Therefore, all three models mentioned above can be used. Y = a + bX Represent it using the equation of a straight line. Then calculate it using the least squares method. , and correlation coefficient The specific calculation method is as follows:
[0027] (5) (6) (7) in: (8) (9) (10) (11) (12) In equations (5)-(12): The logarithmic mean of the aging time t. This represents the average value of performance P.
[0028] Comparing the value with the critical value can be used to determine the magnitude of the correlation between variables and to perform a correlation test. This is done with a confidence level of 80% (significance level of 0.2) and degrees of freedom... Found The value, and compared with the calculated value. Value comparison, if Then X and Y have a linear relationship, and the value of b is the constant K, which represents the rate of change of performance at that temperature; if If the relationship between X and Y is not linear, a more suitable mathematical aging model should be selected. The rate of change of the propellant's mechanical properties can be obtained using the above method. Combining the finite element calculation results with the mechanical property data obtained from the aging model, the damage state of the propellant can be comprehensively judged, and its service life can be predicted.
[0029] The aforementioned existing technologies suffer from two significant drawbacks: First, when using static mechanical parameters for modeling and analysis, the time-varying characteristics of the propellant material's mechanical properties during long-term storage are not adequately considered, leading to significant deviations in lifetime prediction results. Second, current damage criteria primarily rely on single mechanical index thresholds, lacking a systematic consideration of the material damage evolution mechanism under multi-field coupling effects, resulting in an overly simplistic assessment dimension. These technical limitations not only affect the accuracy of lifetime prediction but also hinder the improvement of the solid rocket motor reliability assessment system.
[0030] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.
[0031] Figure 1 This is a schematic diagram of a composite solid propellant lifetime prediction method described in this specification, which specifically includes the following steps: S101: Obtain the mechanical property characterization data of the composite solid propellant and determine the aging rate equation based on the mechanical property characterization data.
[0032] In this embodiment, the mechanical property characterization data includes tensile strength aging data and elastic modulus aging data, and the aging rate equations include tensile strength decay equations and elastic modulus decay equations.
[0033] The aging rate equation is determined based on mechanical property characterization data, specifically including: Based on the aging data of tensile strength and elastic modulus, respectively, the preset mathematical models were fitted using the least squares method to determine the data of temperature-tensile property change rate and temperature-elastic property change rate, respectively. Based on the temperature-tensile property rate of change data and the temperature-elastic property rate of change data, the linear equations corresponding to the Arrhenius equation were fitted using the least squares method to determine the tensile strength decay equation and the elastic modulus decay equation, respectively.
[0034] For example, in order to obtain the mechanical property characterization data of the propellant sample under test at different test temperatures and the corresponding time data, the following two experiments can be conducted: 1. Accelerated aging test at high temperature under different constant stresses High-temperature accelerated aging tests were conducted in an oil bath chamber with a temperature accuracy of ±1℃; the relative humidity of the test environment was less than 50%RH. The tests were conducted according to QJ2328A-2005 "High-Temperature Accelerated Aging Test Method for Composite Solid Propellants". Aging samples were taken at each aging temperature. Different propellant samples were obtained. (in i A value of 1 indicates an aging temperature of The results, among which j A value of 1 indicates an aging time of [value missing]. (Results)
[0035] 2. Mechanical property characterization experiments after aging The propellant samples obtained in Experiment 1 underwent uniaxial constant-speed tensile testing using an electronic universal testing machine at a test temperature of 25℃±2℃. The tensile speed during the constant-speed tensile test was 100 mm / min. The mechanical property characterization data of the propellant samples were obtained through the experiment: maximum elongation... initial modulus and tensile strength The data.
[0036] Optionally, the mechanical performance characterization data in this embodiment may also include other data, such as elastic modulus aging data, etc., without specific limitations.
[0037] For example, after obtaining the mechanical property characterization data, time data, and data at different test temperatures in S101 above (using the propellant sample) (in A value of 1 represents the tensile strength at an aging temperature of 50°C. For example, the following steps can be performed: Taking the logarithm of both sides of equation (3) yields: (13) make: , , , The equation can be transformed into a linear equation as follows: .
[0038] Tensile strength from mechanical property characterization data is used as... The corresponding time is Substitute The unknown coefficients can be obtained from equations (5)-(12). Substituting these unknown coefficients into equation (3), the tensile strength of the propellant at an aging temperature of 50℃ can be obtained. The regression equation for one temperature can be derived by analogy, and the regression equations for other temperatures can be obtained by analogy.
[0039] Take the logarithm of both sides of equation (4), and let... , , , The equation can be transformed into a linear equation as follows: .
[0040] Substituting the above unknown coefficients into equation (3) yields the following results. for Its corresponding temperature is Substitute By fitting the equation, the coefficients can be obtained, and then the coefficients can be substituted back into equation (3). Take the initial value of tensile strength. This yields the tensile strength decay equation for the propellant.
[0041] For example, the initial elastic modulus decay equation in this embodiment can be: in, This indicates the rate of change of the elastic modulus. Indicates the initial modulus. This represents the constant representing the rate of change of performance in relation to temperature; This indicates the aging time, expressed in days (d).
[0042] The method for obtaining the elastic modulus decay equation can refer to the method for generating the tensile strength decay equation. First, the aging mechanical properties (elastic modulus aging data) of the propellant can be obtained through high-temperature accelerated aging tests. The corresponding propellant mechanical properties can then be fitted using the Arrhenius equation to obtain the elastic modulus decay equation.
[0043] For example, in the formula for calculating the safety factor for dehumidification damage, This represents the initial porosity of the propellant, before it is subjected to load, and is a damage variable. As porosity increases during loading, the damage variable... It also gradually increases. When When it approaches 0, the damage The value gradually approaches 1, indicating that the propellant is nearing damage.
[0044] Based on this, in one or more embodiments of this specification, the executing entity can be a hardware device or system with multimodal data acquisition, processing and analysis capabilities, including servers, edge computing devices, etc.
[0045] The server mentioned in this manual can be a server set up on a business platform, or a device such as a desktop computer or laptop computer capable of executing the solution described in this manual. For ease of explanation, the following description will only focus on the server as the execution subject.
[0046] S102: Embed the aging rate equation in the UMAT subroutine of the ABAQUS software to establish the time-varying relationship between mechanical performance characterization data and aging time; wherein, the UMAT subroutine is used to simulate the time-varying characteristics of the mechanical performance characterization data of composite solid propellants as a function of time.
[0047] In this embodiment, the time-varying feature relationship is updated in real time; The method for real-time updating of time-varying feature relationships is as follows: The elastic modulus decay equation is invoked based on the time variable of the current calculation step to calculate the modulus decay, update the elastic modulus, and correct the material stiffness matrix through the Jacobian matrix to update the time-varying characteristic relationship.
[0048] The constitutive model of composite solid propellant materials is applied in the UMAT subroutine; The constitutive model of the composite solid propellant material is a custom material model used to describe the mechanical behavior of the composite solid propellant.
[0049] Optionally, before S102, a geometric model corresponding to the target propellant can be constructed based on the geometry of the target propellant, and corresponding boundary conditions and various loads can be applied.
[0050] For example, this invention achieves the simulation of time-varying material parameters by developing an ABAQUS User Material Subroutine (UMAT). The UMAT, a user-defined material constitutive model interface developed using the Fortran language, can effectively characterize the evolution of the mechanical properties of solid propellants over aging time. Its advantage lies in the fact that the ABAQUS solver calls the user-defined material constitutive relation through the UMAT subroutine in each increment step, thereby updating the material state variables in real time.
[0051] To address the propellant aging problem, the aging rate of material parameters was embedded in UMAT, establishing a correlation between mechanical properties (such as modulus, Poisson's ratio, etc.) and aging time. This numerical implementation method maintains the numerical stability of finite element solutions and achieves refined simulation of complex aging behavior.
[0052] The tensile strength decay equation and the elastic modulus decay equation can be embedded into the UMAT subroutine using the constitutive model parameterization method. The specific implementation path is as follows: in the material state update algorithm, based on the time variable of the current calculation step... The modulus attenuation is calculated by calling equation (1) in real time, and the material stiffness matrix is dynamically corrected by updating the Jacobian matrix.
[0053] S103: The UVARM subroutine of the ABAQUS software is used to obtain the data of the composite solid propellant under test at the target integration point, and the data of the target integration point is used to calculate the safety factor of the composite solid propellant under test through time-varying characteristic relationship; the UVARM subroutine is used to solve the safety factor of the composite solid propellant, and the data of the target integration point includes stress, strain, displacement, temperature field and cumulative time.
[0054] For example, addressing the limitations of ABAQUS software in calculating the safety factor, this invention implements the calculation of the propellant safety factor by writing a UVARM subroutine. The UVARM interface allows real-time acquisition of integration point data such as stress, strain, displacement, temperature field, and cumulative time. By combining aging performance data with the current stress and strain state of the propellant grain, precise calculations are performed to obtain the propellant grain's safety factor and life prediction.
[0055] S104: Determine the estimated lifetime of the composite solid propellant to be tested based on its safety factor.
[0056] In this embodiment, the safety factor of the composite solid propellant to be tested includes the maximum elongation safety factor, the tensile strength safety factor, and the dewetting damage safety factor; The formula for calculating the maximum elongation safety factor is as follows: in, This represents the safety factor for maximum elongation. This indicates the maximum elongation of the propellant after aging. This indicates the actual elongation rate under the current operating conditions; The formula for calculating the tensile strength safety factor is: in, This represents the safety factor for tensile strength. Indicates the tensile strength of the propellant after aging. This indicates the actual stress under the current operating conditions; The formula for calculating the dehumidification damage safety factor is as follows: in, Indicates the safety factor for dehumidification damage. Indicates the initial porosity of the propellant. This indicates the porosity under the current operating conditions. This indicates the actual strain under the current operating conditions. Represents the natural constant.
[0057] In this embodiment, the method further includes: using the UVARM subroutine to map the safety factor into a field variable, and generating a three-dimensional damage distribution cloud map in the ABAQUS software post-processing.
[0058] For example, the degree of material damage is quantitatively assessed based on the maximum elongation coefficient, tensile strength coefficient, and desiccation damage coefficient, and a safety factor is calculated comprehensively. The final life assessment value is determined using the minimum value principle of the triaxial criteria, that is, the minimum value among the performance indicators is used as the safety factor. As shown in the following formula:
[0059] in, These are the maximum elongation coefficient, tensile strength coefficient, and dehumidification damage coefficient, respectively. This is for the safety factor.
[0060] Ultimately, through UVARM, The data is mapped to field variables, and a three-dimensional damage distribution cloud map is generated in ABAQUS post-processing.
[0061] based on Figure 1 The composite solid propellant lifetime prediction method shown establishes a time-varying characteristic relationship between mechanical performance characterization data and aging time, so that lifetime prediction is based on the physical mechanism of material aging rather than simple empirical extrapolation. The aging rate equation is embedded in the ABAQUS UMAT subroutine, so that the mechanical behavior (constitutive relation) of the material can dynamically and accurately reflect the influence of the aging process, thereby improving the accuracy of composite solid propellant lifetime prediction.
[0062] Another bottleneck in the current technology for predicting the lifespan of composite solid propellants is that conventional safety factor calculations are based on initial mechanical properties and do not consider the real-time coupling relationship between material load-bearing capacity and structural stress state during aging. To address this issue, this invention combines dynamic performance data with propellant data at the target integration point to calculate the current safety factor and the final lifespan estimate, thereby effectively assessing the propellant's operational safety and lifespan. By calculating the safety factor of the composite solid propellant under test using time-varying characteristic relationships from the target integration point data, including stress, strain, displacement, temperature field, and cumulative time, the accuracy of composite solid propellant lifespan prediction can be further improved.
[0063] When applying the composite solid propellant lifetime prediction method provided in this manual, it is not necessary to consider... Figure 1 The steps shown are executed in sequence. The specific execution order of each step can be determined as needed, and this manual does not impose any restrictions on it.
[0064] The above are one or more embodiments of the composite solid propellant lifetime prediction method provided in this specification. Based on the same idea, this specification also provides a corresponding composite solid propellant lifetime prediction device, such as... Figure 3 As shown.
[0065] Figure 3 A schematic diagram of a composite solid propellant lifetime prediction device provided in this specification includes: The data acquisition module is specifically used to acquire mechanical property characterization data of composite solid propellants and determine the aging rate equation based on the mechanical property characterization data. The data processing module is specifically used to embed the aging rate equation into the UMAT subroutine of the ABAQUS software to establish the time-varying relationship between mechanical performance characterization data and aging time. The UMAT subroutine is used to simulate the time-varying characteristics of the mechanical performance characterization data of the composite solid propellant over time. The UVARM subroutine of the ABAQUS software acquires data of the composite solid propellant under test at the target integration point, and calculates the safety factor of the composite solid propellant under test using the time-varying characteristic relationship. The UVARM subroutine is used to solve for the safety factor of the composite solid propellant; the data at the target integration point includes stress, strain, displacement, temperature field, and cumulative time. The life prediction module is specifically used to determine the life prediction value of the composite solid propellant under test based on the safety factor of the composite solid propellant under test.
[0066] Specific limitations regarding the composite solid propellant lifetime prediction device can be found in the limitations of the composite solid propellant lifetime prediction method described above, and will not be repeated here. Each module in the aforementioned composite solid propellant lifetime prediction device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.
[0067] This specification also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described... Figure 1 A method for predicting the lifetime of composite solid propellants is provided.
[0068] This instruction manual also provides Figure 4 The schematic diagram of the computer device shown is as follows: Figure 4 At the hardware level, the computer device includes a processor, internal bus, network interface, memory, and non-volatile memory, and may also include other hardware required for business operations. The processor reads the corresponding computer program from the non-volatile memory into memory and then runs it to achieve the above-mentioned functions. Figure 1 A method for predicting the lifetime of composite solid propellants is provided.
[0069] 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 methods described above. Any references to memory, storage, 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, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.
[0070] 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.
Claims
1. A method for predicting the lifetime of a composite solid propellant, characterized in that, include Obtain mechanical property characterization data of composite solid propellants, and determine the aging rate equation based on the mechanical property characterization data; An aging rate equation is embedded in the UMAT subroutine of the ABAQUS software to establish the time-varying relationship between mechanical performance characterization data and aging time; the UMAT subroutine is used to simulate the time-varying characteristics of the mechanical performance characterization data of composite solid propellants over time. The UVARM subroutine of the ABAQUS software is used to obtain the data of the composite solid propellant under test at the target integration point, and the safety factor of the composite solid propellant under test is obtained by calculating the data of the target integration point through the time-varying characteristic relationship. The UVARM subroutine is used to solve the safety factor of the composite solid propellant. The data of the target integration point includes stress, strain, displacement, temperature field and cumulative time. Based on the safety factor of the composite solid propellant to be tested, the estimated lifetime of the composite solid propellant to be tested is determined.
2. The method for predicting the lifetime of composite solid propellants as described in claim 1, characterized in that, The mechanical property characterization data includes tensile strength aging data and elastic modulus aging data, and the aging rate equations include tensile strength decay equations and elastic modulus decay equations. The determination of the aging rate equation based on mechanical property characterization data specifically includes: Based on the aging data of tensile strength and elastic modulus, respectively, the preset mathematical models were fitted using the least squares method to determine the data of temperature-tensile property change rate and temperature-elastic property change rate, respectively. Based on the temperature-tensile property rate of change data and the temperature-elastic property rate of change data, the linear equations corresponding to the Arrhenius equation were fitted using the least squares method to determine the tensile strength decay equation and the elastic modulus decay equation, respectively.
3. The method for predicting the lifetime of composite solid propellants as described in claim 1, characterized in that, The time-varying feature relationship is updated in real time; The method for real-time updating of the time-varying feature relationship is as follows: The elastic modulus decay equation is invoked based on the time variable of the current calculation step to calculate the modulus decay, update the elastic modulus, and correct the material stiffness matrix through the Jacobian matrix to update the time-varying characteristic relationship.
4. The method for predicting the lifetime of composite solid propellants as described in claim 1, characterized in that, The safety factor of the composite solid propellant to be tested includes the maximum elongation safety factor, the tensile strength safety factor, and the dewetting damage safety factor. The formula for calculating the maximum elongation safety factor is as follows: in, This represents the safety factor for maximum elongation. This indicates the maximum elongation of the propellant after aging. This indicates the actual elongation rate under the current operating conditions; The formula for calculating the tensile strength safety factor is: in, This represents the safety factor for tensile strength. Indicates the tensile strength of the propellant after aging. This indicates the actual stress under the current operating conditions; The formula for calculating the dehumidification damage safety factor is as follows: in, Indicates the safety factor for dehumidification damage. Indicates the initial porosity of the propellant. This indicates the porosity under the current operating conditions. This indicates the actual strain under the current operating conditions. Represents the natural constant.
5. The method for predicting the lifetime of composite solid propellants as described in claim 1, characterized in that, The constitutive model of composite solid propellant materials is applied in the UMAT subroutine; The constitutive model of the composite solid propellant material is a custom material model used to describe the mechanical behavior of the composite solid propellant.
6. The method for predicting the lifetime of composite solid propellants as described in claim 1, characterized in that, The method further includes: The UVARM subroutine is used to map the safety factor to field variables, and a three-dimensional damage distribution cloud map is generated in the ABAQUS software post-processing.
7. A composite solid propellant lifetime prediction device, characterized in that, include: The data acquisition module is specifically used to acquire mechanical property characterization data of composite solid propellants and determine the aging rate equation based on the mechanical property characterization data. The data processing module is specifically used to embed the aging rate equation into the UMAT subroutine of the ABAQUS software to establish the time-varying relationship between mechanical performance characterization data and aging time. The UMAT subroutine is used to simulate the time-varying characteristics of the mechanical performance characterization data of the composite solid propellant over time. The UVARM subroutine of the ABAQUS software acquires data of the composite solid propellant under test at the target integration point, and calculates the safety factor of the composite solid propellant under test using the time-varying characteristic relationship. The UVARM subroutine is used to solve for the safety factor of the composite solid propellant; the data at the target integration point includes stress, strain, displacement, temperature field, and cumulative time. The life prediction module is specifically used to determine the life prediction value of the composite solid propellant under test based on the safety factor of the composite solid propellant under test.
8. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the method described in any one of claims 1 to 6.
9. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described in any one of claims 1 to 6.