Whole-process simulation and blasting pressure prediction method for weak-rigidity core mold composite material shell

Abstract

The invention discloses a full-process simulation and blasting pressure prediction method for a weak-rigidity core mold composite material shell, and belongs to the technical field of solid rocket engine integrated explosive forming shell design. The method comprises the following steps: designing an equal residual stress tension system based on a fiber winding layer stress theory; constructing a finite element model in the shell winding process, iteratively optimizing a tension system and determining a stress field and a strain field after winding; taking the stress field and the strain field as predefined fields, constructing a finite element model in the curing process, and calculating the stress field and the strain field after curing; and based on the stress field and the strain field after curing, progressive damage analysis is realized through a three-dimensional Hashin criterion, and the maximum blasting pressure of the shell with the powder is predicted. The problems that in the prior art, a tension system lacks collaborative optimization, simulation cannot cover the whole process, and blasting prediction deviation is large are solved, precise coupling prediction of the process and performance is achieved, and theoretical support is provided for optimization of the integrated forming process.

Description

Technical Field

[0001] This invention belongs to the field of integrated propellant-coated shell design technology for solid rocket engines, specifically involving a full-process simulation and explosion pressure prediction method for a weak stiffness mandrel composite material shell. Background Technology

[0002] The integrated propellant-coated shell of a solid rocket motor is a core component of aerospace propulsion systems, and its structural integrity and load-bearing capacity directly determine the engine's operational reliability and safety. The core challenge in manufacturing this type of shell lies in using propellant grains as a weak-stiffness mandrel, on which composite materials are wound and cured. Compared to conventional metal mandrels, the stiffness of propellant grains is only 1 / 50 to 1 / 100 that of metal, making them highly susceptible to irreversible deformation or cracking during manufacturing. Therefore, a precise balance must be struck between the stability of the mandrel structure and the load-bearing capacity of the shell—a long-standing technical bottleneck for the industry.

[0003] Existing technologies in this field suffer from four key problems, all of which are core pain points that can be specifically addressed by the technical means of this invention: First, the tension regime design lacks a quantitative and collaborative optimization mechanism. Traditional winding processes often employ constant tension or empirical gradient tension regimes, failing to establish a quantitative correlation between the propellant damage threshold and the prestress of the shell fibers. When the tension is too high, the propellant may undergo plastic deformation or even crack due to loads exceeding its ultimate strength, resulting in direct product scrap. When the tension is too low, the shell fibers cannot form sufficient prestress, leading to a 15%–30% decrease in load-bearing capacity during subsequent detonation, failing to meet engine design requirements. Existing technologies lack both clear quantitative targets for tension design and an iterative optimization logic based on the balance between mandrel safety and shell performance, resulting in tension regime design relying on experience and exhibiting extremely poor consistency and reliability.

[0004] Secondly, the simulation of the winding process is disconnected from the actual process, resulting in significant deviations in stress calculations. Existing simulation methods often employ simplified geometric models, neglecting key structures such as metal joints, insulation layers, and linings, and only simplifying the modeling of the fiber winding layer and the propellant core mold. This leads to distortions in the simulation of stress transfer paths. Furthermore, the resin is in a viscous state during the winding process, making its contribution to the stiffness of the composite material difficult to characterize directly. Traditional methods either ignore the resin's influence or use static load application to simulate tension, failing to reproduce the dynamic process of layer-by-layer winding. This results in a deviation of over 25% between the simulated stress field and the actual stress field after winding, failing to provide effective data support for subsequent process optimization.

[0005] Third, the multi-field coupling effect of heat, chemical, and mechanical forces during the curing stage is not effectively characterized, leading to a break in the stress inheritance chain. During the curing process with the drug, the cross-linking reaction of the resin matrix releases a large amount of heat, forming a non-uniform temperature field. The difference between the resin curing shrinkage and the thermal expansion coefficient of the drug cartridge core mold can be an order of magnitude, and their mutual constraints significantly alter the initial stress state formed during the winding stage. Existing technologies either directly ignore the influence of the curing process on the shell stress or use an adaptive step-size algorithm for curing simulation, resulting in abrupt changes in the degree of curing and interpolation errors. This leads to insufficient accuracy in the transmission of field variables, making it impossible to accurately capture the evolution of the stress field after curing, and consequently causing subsequent performance predictions to lack a reliable stress basis.

[0006] Fourth, the prediction of burst pressure ignores key influencing factors, resulting in significant assessment bias. Existing shell burst pressure prediction methods mostly model the cured shell separately, failing to consider residual stresses generated during winding and curing. Furthermore, they employ a single failure criterion (such as the maximum normal stress criterion) to characterize composite material failure, failing to distinguish between multiple failure modes such as fiber tension, fiber compression, and matrix cracking. This makes the prediction results unable to reflect the failure mechanisms under actual operating conditions, leading to burst pressure prediction errors generally exceeding 15% to 20%. This makes it difficult to guide shell process optimization and safety performance assessment, increasing the trial-and-error costs and timelines of product development.

[0007] In summary, existing technologies for manufacturing and performance prediction of weak stiffness mandrel composite shells suffer from a series of interconnected technical problems, such as unquantified optimization of tension regime, distortion in winding simulation, fracture of curing stress transmission, and large deviations in burst pressure prediction. There is an urgent need to establish a full-process simulation system covering tension regime design, winding process simulation, curing stress evolution, and burst pressure prediction. By accurately quantifying the stress inheritance laws at each stage, precise coupling prediction of process and performance can be achieved, providing reliable theoretical support for the design and manufacturing of integrated propellant-coated shells for solid rocket motors. Summary of the Invention

[0008] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a full-process simulation and blast pressure prediction method for weak stiffness mandrel composite material shells. This method performs full-process process simulation of the winding-curing-blasting of weak stiffness mandrels, which solves the technical problems of large deviations in the prediction of the blast strength of explosive shells due to isolated analysis of process steps, inability to accurately characterize the dynamic evolution of the stress field throughout the process, and lack of a mechanism for synergistic optimization of the quantified charge damage threshold and shell performance. This invention achieves accurate prediction of the impact of the complete process flow, including tension regime, winding, and curing, on the performance of explosive shells.

[0009] The present invention adopts the following technical solution: A method for full-process simulation and burst pressure prediction of a weak stiffness mandrel composite material shell includes the following steps: S1. Based on the fiber winding layer stress theory, design the residual stress tension regime of fiber winding, etc. S2. Based on the residual stress tension regime of fiber winding designed in step S1, construct a finite element model of the shell winding process. Guided by the balance between the safety of the propellant and the performance of the shell, iteratively optimize the tension regime based on the simulation results to determine the stress field and strain field at the end of the optimized winding. S3. Using the stress field and strain field determined in step S2 after the winding is completed as a predefined field, construct a finite element model of the shell curing process, and calculate the stress field and strain field after the shell curing is completed. S4. Using the stress field and strain field obtained in step S3 after the shell solidification is completed as a predefined field, construct a finite element model for predicting the performance of the explosive shell. Through progressive damage analysis, predict the failure of the explosive shell and determine its maximum blast pressure.

[0010] Preferably, the weak stiffness mandrel is a propellant grain.

[0011] Preferably, in step S1, based on the formula for residual stress of the fiber winding layer, an equal residual stress tension regime is designed with a preset residual stress value of the winding layer as the target.

[0012] Preferably, step S2 includes: S201. Based on the actual geometric dimensions and material performance parameters, establish a three-dimensional model of the composite material shell, including the fiber winding layer, metal joint, insulation layer, lining layer, and propellant core mold. S202. The equivalent cooling method is adopted to simulate the prestress generated by winding tension through the temperature field. S203. The progressive simulation of layer-by-layer contact activation is achieved by using the unit dead-live method, and the prestress of the winding layer is applied in combination with the equivalent cooling method. S204. Based on the simulation output of the finite element model of the shell winding process, compare the maximum stress of the propellant with the safe strength of the propellant, iteratively update the tension regime until the optimized tension regime corresponding to the maximum remaining stress of the winding layer under the safe strength of the propellant is obtained, and determine the stress field and strain field under this state.

[0013] Preferably, in step S202, the equivalent cooling method continuously changes the initial temperature field within the i-th winding layer, so that the simulated output residual stress of the winding layer reaches the predetermined target residual stress value.

[0014] Preferably, in step S3, the finite element model of the shell curing process uses the stress field and strain field at the end of the winding as the predefined fields, introduces unsteady temperature field boundary conditions, and adopts a fixed incremental step size control strategy to calculate and output the stress field and strain field after the shell curing is completed.

[0015] Preferably, in step S4, the finite element model for predicting the performance of the drug-loaded shell adopts the three-dimensional Hashin failure criterion to characterize the fiber-dominated failure and matrix-dominated failure of the composite material layer.

[0016] Preferably, the three-dimensional Hashin failure criterion includes criteria for four failure modes: fiber tensile failure, fiber compression failure, matrix tensile failure, and matrix compression failure.

[0017] Preferably, in step S4, the stress and strain field after the curing of the explosive casing is completed is used as a predefined field, and the maximum internal pressure when the explosive casing fails is obtained by performing progressive damage analysis on the finite element model for predicting the performance of the explosive casing.

[0018] Secondly, embodiments of the present invention provide a full-process simulation and burst pressure prediction system for a weak stiffness mandrel composite material shell, comprising: The design module is used to design residual stress tension regimes for fiber winding based on the fiber winding layer stress theory. The optimization module is used to construct a finite element model of the shell winding process based on the designed tension regime. Guided by the balance between the safety of the propellant and the performance of the shell, the module iteratively optimizes the tension regime based on the simulation results and determines the stress field and strain field at the end of the winding after optimization. The simulation module is used to construct a finite element model of the shell curing process by taking the stress field and strain field at the end of the winding as a predefined field, and to calculate the stress field and strain field after the shell curing is completed. The prediction module is used to construct a finite element model for predicting the performance of the explosive-loaded shell by using the stress and strain fields after the shell has been cured as predefined fields. Through progressive damage analysis, it predicts the failure of the explosive-loaded shell and determines its maximum blast pressure.

[0019] Thirdly, a computer device includes 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 steps of the above-described method for full-process simulation and burst pressure prediction of a weak stiffness mandrel composite material shell.

[0020] Fourthly, embodiments of the present invention provide a computer-readable storage medium, including a computer program, which, when executed by a processor, implements the steps of the above-described method for full-process simulation and burst pressure prediction of a weak stiffness mandrel composite material shell.

[0021] Fifthly, a chip includes 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 steps of the above-described method for full-process simulation and burst pressure prediction of a weak stiffness mandrel composite material shell.

[0022] Sixthly, embodiments of the present invention provide an electronic device, including a computer program, which, when executed by the electronic device, implements the steps of the above-mentioned method for full-process simulation and burst pressure prediction of a weak stiffness mandrel composite material shell.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects: A method for full-process simulation and blast pressure prediction of a weak-stiffness mandrel composite shell is proposed. By using the stress and strain fields of the preceding steps as predefined fields for the subsequent model, it accurately inherits the stress evolution law in the process history, solving the problem that traditional methods cannot quantify the stress inheritance of the entire process. At the same time, the tension regime is optimized with the safety of the propellant and the performance of the shell as the guide, avoiding the problem of propellant cracking due to solely pursuing shell strength, or excessively conservative design that reduces the shell's load-bearing capacity. The method accurately quantifies and transmits the stress inheritance and evolution mechanism in the entire chain of "winding-curing-blasting", overcoming the shortcomings of existing technologies that isolate the analysis of a single process link and ignore the influence of historical stress, thus significantly improving the accuracy of predicting the actual blast pressure of the propellant shell.

[0024] Furthermore, by employing the general formula for residual tension in the winding layers, with a specific residual stress target of 40 MPa and a winding layer design of 7 layers, the tension regime is transformed from empirical to precise. Clearly defining the radial / circumferential physical quantities and the parameters of the fiber and propellant mandrel ensures the rigor of the design process; fixing the target value and the number of layers provides a clear benchmark for subsequent simulation and optimization, avoiding the blindness of tension design. Ensuring the balance of residual stress in each winding layer prevents instability in the shell structure due to interlayer stress differences and accurately matches the propellant damage threshold.

[0025] Furthermore, by combining the equivalent cooling method and the unit life-death method, the layer-by-layer loading process of actual winding was simulated with high precision. Through the iterative optimization mechanism, the automatic balance optimization between the safety of the propellant and the prestress of the shell was realized for the first time in the simulation, and the optimal process parameters that take into account both requirements were directly output, solving the industry problem that the winding tension of weak stiffness mandrel is difficult to determine based on experience.

[0026] Furthermore, by adjusting the virtual temperature field to equivalent mechanical tension, the thermodynamic module is cleverly utilized, avoiding the difficulty of directly applying complex boundary conditions. This ensures the numerical stability of the prestress applied in the simulation and its consistency with the actual physical process, which is a key technical guarantee for constructing a high-fidelity winding model.

[0027] Furthermore, by introducing an unsteady temperature field, the actual physical process of resin crosslinking exothermics is reflected; the fixed step size strategy avoids computational instability and ensures the accuracy of the transfer of thermo-chemical field variables to the mechanical field.

[0028] Furthermore, by importing the stress field after winding as a predefined field, the stress inheritance of the process history is realized, ensuring the continuity of stress evolution throughout the entire process. Unsteady-state temperature field boundary conditions are introduced to restore the non-uniform temperature distribution caused by the exothermic cross-linking of the resin matrix. A fixed incremental step size control strategy is adopted to avoid abrupt changes in curing degree and interpolation errors, ensuring the accuracy of the transmission of field variables such as temperature and curing degree. These designs enable the curing process simulation to accurately capture the stress changes caused by the mutual constraint between curing shrinkage and mandrel thermal expansion. The output post-curing stress and strain fields truly reflect the actual structural state after curing, solving the problem of explosion prediction deviation caused by neglecting stress changes during the curing stage in traditional methods, and providing an accurate prestressing basis for the final explosion pressure prediction.

[0029] Furthermore, by decomposing failure behavior into four modes—fiber tension, fiber compression, matrix tension, and matrix compression—and clarifying the failure mechanism of each mode, progressive damage analysis can accurately capture the initiation and propagation of damage. The three-dimensional Hashin criterion, combined with the failure physics mechanism, considers the influence of multiple factors such as normal stress and shear stress on failure, avoiding the limitations of traditional single failure criteria and accurately distinguishing between fiber, matrix, and interlayer failure types. This precise failure discrimination enables the explosive casing performance prediction model to accurately simulate damage evolution under different pressure loads, and the final output maximum blast pressure more closely matches the actual failure situation. This solves the evaluation bias problem caused by neglecting multi-mode failure in existing predictions, significantly improving the accuracy and reliability of blast pressure prediction.

[0030] Furthermore, by gradually increasing the load, the dynamic process of damage accumulation and expansion until overall failure is observed, thereby determining the ultimate bearing capacity of the structure.

[0031] Furthermore, by focusing the method on the highly challenging field of integrated propellant molding for solid rocket motors, the invention highlights its targeted and practical value in solving the unique problems of easy core mold deformation and strong process coupling.

[0032] It is understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0033] In summary, the method of this invention takes full-process simulation as its core, and solves the pain points of existing technologies such as isolated simulation, lack of synergistic optimization of tension, and large deviation in explosion prediction by quantitatively designing tension regime, progressive winding simulation, precise solidification stress transfer, and multi-mode failure discrimination. It achieves a balance between the safety of the propellant charge and the performance of the shell, and provides scientific support for integrated molding process.

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0035] Figure 1 This is a flowchart of the method of the present invention; Figure 2 A schematic diagram of a three-dimensional model of a weak stiffness mandrel composite material shell provided by the present invention; Figure 3 This is a schematic diagram of the residual stress in the fiber shell output from the drug-loaded shell winding model provided by the present invention; Figure 4 This is a schematic diagram of the residual stress of the propellant grain output from the propellant-coated casing winding model provided by the present invention; Figure 5 A schematic diagram of the overall residual stress output from the solidification model of the drug-loaded shell provided by this invention; Figure 6 A schematic diagram of the first layer damage when the finite element model for predicting the performance of the explosive-loaded casing is used to predict the failure of the explosive-loaded casing, as provided by the present invention. Figure 7 A schematic diagram of the third layer damage when the finite element model for predicting the performance of the explosive casing provided by the present invention predicts the failure of the explosive casing. Figure 8 A schematic diagram of the fifth layer damage when the finite element model for predicting the performance of the explosive casing provided by the present invention predicts the failure of the explosive casing. Figure 9 A schematic diagram of the 7th layer damage when the finite element model for predicting the performance of the explosive casing provided by the present invention is used to predict the failure of the explosive casing. Figure 10 A schematic diagram of a computer device provided in an embodiment of the present invention; Figure 11 This is a block diagram of a chip provided according to an embodiment of the present invention.

[0036] Among them, 60. Computer equipment; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access memory unit; 6202. Cache memory unit; 6203. Read-only memory unit; 6204. Program / utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0039] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0040] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0041] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0042] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0043] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0044] This invention provides a method for full-process simulation and explosive pressure prediction of a weak-stiffness mandrel composite shell. Based on the stress theory of fiber winding layers, a residual stress tension regime is designed for fiber winding. A finite element model of the shell winding process is constructed. Guided by the balance between the safety of the explosive charge and the performance of the shell, and based on the winding simulation results, the tension regime is optimized. Based on this optimized tension regime, the stress and strain fields after winding are determined. Using the stress and strain fields after winding as predefined fields, a finite element model of the shell curing process is constructed to predict the stress and strain fields after curing. Finally, using the stress and strain fields after curing as predefined fields, a finite element model for predicting the performance of the explosive-loaded shell is constructed to predict the maximum explosive pressure at the time of shell failure. This invention can quantify and predict the impact of the complete process flow, including tension regime, winding, and curing, on the performance of the explosive-loaded shell, providing a theoretical basis for optimizing the manufacturing process of integrated explosive-loaded shells.

[0045] Please see Figure 1 This invention discloses a full-process simulation and blast pressure prediction method for a weak stiffness mandrel composite material shell, where the weak stiffness mandrel refers to a propellant grain. The full process encompasses a complete set of procedures for winding the composite material shell onto the propellant grain mandrel, curing with propellant, and conducting a propellant-loaded blast test. The specific steps are as follows: S1. Based on the fiber winding layer stress theory, design the residual stress tension regime of fiber winding, etc. Utilizing the remaining tension of the following winding layers The general solution formula is used to design a 7-layer constant residual stress tension regime with a target residual stress value of 40 MPa for the winding layer.

[0046] Among them, subscript and Representing physical quantities along the radial and circumferential directions respectively, the subscripts are... and The physical quantities corresponding to composite fiber and propellant core mold are not specified. The inner diameter of the propellant core mold. The outer diameter of the drug cartridge core mold. The outer diameter after winding is complete. This represents the total number of winding layers. The thickness of a single fiber layer To wrap the outermost layer j inner diameter, For the first Inner diameter of the winding layer For the first The outer diameter of the layer of winding, To reduce the tension on the outermost layer, For displacement, In response, For stress, Poisson's ratio, It is the elastic modulus.

[0047] The tension regime defines the initial tension of each winding layer during the winding of the shell; the equal residual stress tension regime is the tension regime that ensures the residual stress of each winding layer is equal after winding is completed; based on the fiber winding layer stress theory, the design of the equal residual stress tension regime for fiber winding is based on the residual tension of the winding layer. Based on the general solution formula, the initial stress and residual stress of each winding layer are designed with the residual stress value of a certain winding layer as the target.

[0048] S2. Construct a finite element model of the shell winding process, and optimize the tension regime based on the winding simulation results, taking the balance between the safety of the propellant and the performance of the shell as the guide. Based on the optimized tension regime, determine the stress and strain fields after the winding is completed. S201, Geometric modeling, such as Figure 2 As shown, based on the actual geometric dimensions and material performance parameters, a three-dimensional full-size model of a weak stiffness mandrel composite shell, including a fiber winding layer, metal joint, insulation layer, lining, and propellant core mold, is established. S202. The equivalent cooling method is set up by introducing a temperature field to convert the shrinkage stress generated by the cooling of the composite winding layer into the prestress generated by the winding tension. Specifically, for a winding container with 7 winding layers, the initial temperature field in the i-th winding layer is continuously changed to Φ(i), and the residual stress of each winding layer is output by finite element model simulation of the shell winding process. When the temperature field Φ(i) of the winding layer causes the residual stress of the layer to reach the predetermined residual stress σ(i), the winding of the layer is considered to be completed.

[0049] The governing equation for the equivalent cooling method is:

[0050] in, Indicates equivalent cooling. Indicates winding tension. Indicates the longitudinal elastic modulus. Let A represent the coefficient of thermal expansion, and let A represent the cross-sectional area of ​​the fiber bundle. Considering that the resin is in a viscous state during the winding process, its contribution to the stiffness of the composite material is negligible.

[0051] S203. Introducing the unit life-and-death method to achieve progressive simulation of layer-by-layer contact activation, combined with the equivalent cooling method to apply prestress to the winding layer, simulating the actual winding process, specifically including: Disable all composite material units; Layer-by-layer activation: The progressive simulation uses multi-step calculations, with each calculation step activating a layer of "disabled" composite material units. When a load is applied, the temperature field is applied to the activated composite winding layer using an equivalent cooling method to obtain the winding layer stress consistent with the actual winding process.

[0052] The results are output by activating composite material units layer by layer until the calculation is complete. Figure 3 The residual stress field of the shell shown and Figure 4 The residual stress field of the propellant grain is shown.

[0053] S204. Optimize the tension regime. The optimized tension regime is obtained by iteratively updating the simulation results of the finite element model of the shell winding process with the safe strength of the propellant grain. Based on the finite element model of the shell winding process, the maximum stress of the output propellant grain is compared with the safe strength of the propellant grain, specifically including: If the maximum stress of the propellant is less than the safe strength of the propellant, the target residual stress of the winding layer should be appropriately increased, and the simulation results should be re-run to make the maximum stress of the propellant close to the safe strength of the propellant. If the maximum stress of the propellant grain exceeds the safe strength of the propellant grain, the target residual stress of the winding layer should be appropriately reduced, and the simulation results should be re-run to make the maximum stress of the propellant grain close to the safe strength of the propellant grain. Repeat the above process until the optimal tension regime corresponding to the maximum residual stress of the winding layer under the safe strength of the propellant grain is obtained, and the stress and strain fields under this state are determined. According to Figure 4 The residual stress field of the propellant grain shown indicates that the stress on the propellant grain is 0.0024 MPa, which is much less than its strength and meets the set residual stress value of 40 MPa.

[0054] S3. Using the stress and strain fields after winding as predefined fields, construct a finite element model of the shell curing process to predict the stress and strain fields after shell curing, specifically including: As an optimized implementation of the present invention, the solidification simulation calculation process is as follows: Figure 4 As shown, the finite element model of the shell curing process is based on the finite element model of the shell winding process. It introduces the unsteady temperature field required for curing, and the fixed incremental step size control avoids the sudden change in curing degree caused by the adaptive step size algorithm and eliminates the interpolation error, ensuring the accuracy of field variables (such as temperature and curing degree) when they are passed to the mechanical solver. The residual stress field of the shell after winding is used as a predefined field, thereby outputting the stress and strain fields of the shell after curing. S301, Field Variable Transfer: The stress and strain fields determined in step S2 after the winding is completed are imported into the curing model as predefined fields to achieve the inheritance of process history. S302. Based on the established finite element model of the shell winding process, an unsteady temperature field boundary condition is introduced, wherein the unsteady temperature field is the dynamic relationship between temperature and time during shell curing. S303. A fixed incremental step size control strategy based on curing kinetics is adopted, wherein the fixed incremental step size control strategy is to control the entire curing process with a fixed step size. S304. The stress and strain fields of the shell after curing are calculated and output by the finite element model of the shell curing process, such as... Figure 6 As shown.

[0055] S4. Using the stress and strain fields after the shell curing is completed as predefined fields, construct a finite element model for predicting the performance of the explosive-loaded shell to predict the maximum blast pressure when the explosive-loaded shell fails. Specifically, this includes: As an optimized implementation of the present invention, such as Figure 7 As shown, the finite element model for predicting the performance of the drug-carrying shell was established in Abaqus as a full-process multi-factor coupled model covering fiber placement, motion trajectory, process history tension field evolution, and thermo-chemical coupling. S401. The stress and strain fields after the shell curing is completed are set as predefined fields in the finite element model for predicting the performance of the drug-loaded shell. S402. Based on the established finite element model of the shell winding process, a three-dimensional Hashin criterion is introduced to accurately characterize the multi-mode discrimination of fiber, matrix and interlaminar failures. The three-dimensional Hashin criterion, combined with the physical mechanism of failure, decomposes the failure behavior of orthotropic monolayer plates into two main categories: fiber-dominated failure and matrix-dominated failure, and further refines them into four typical failure modes, specifically including: (1) Fiber tensile failure ) When the fiber is subjected to tensile stress, failure is caused by fiber breakage or debonding at the fiber-matrix interface. The criterion is as follows:

[0056] (2) Fiber compression failure ) Fiber-direction compressive stress leads to fiber buckling or micro-shear failure. The criterion expression is:

[0057] (3) Matrix tensile failure ) The criterion for determining whether matrix cracking or interface failure is caused by the combined effect of tensile stress and shear stress in the transverse or thickness direction is:

[0058] (4) Matrix compression failure ( ) The criterion for compressive stress in the transverse or thickness direction inducing matrix shear slip or micro-buckling is the most complex:

[0059] in, / Fiber-oriented tensile / compressive strength; / For the transverse tensile / compressive strength and in-plane shear strength S, S 23 Indicates interlaminar shear strength. σ 1. σ 2、 σ 3 represents the first, second, and third normal stress components; τ 12 τ 13 and τ 23 This refers to interlaminar shear stress.

[0060] S403. Based on the finite element model for predicting the performance of the explosive casing, progressive damage analysis was performed on the casing, and the maximum burst pressure when the weak stiffness mandrel composite material casing failed was found to be 21.3 MPa.

[0061] As pressure increases, the model is able to capture the initiation and evolution of damage.

[0062] The weak stiffness mandrel composite shell is obtained by winding and curing fiber prepreg tape, which is composed of carbon fiber and resin matrix.

[0063] like Figures 6 to 9As shown, the damage propagation cloud maps of the 1st, 3rd, 5th and 7th layers during the failure of the drug-loaded casing are displayed respectively. When uvarm33>1, it indicates fiber tensile failure.

[0064] The maximum burst pressure when the integrated shell of the weak stiffness mandrel composite material failed was finally determined to be 21.3 MPa.

[0065] In another embodiment of the present invention, a full-process simulation and burst pressure prediction system for a weak stiffness mandrel composite material shell is provided. This system can be used to implement the above-mentioned full-process simulation and burst pressure prediction method for a weak stiffness mandrel composite material shell. Specifically, the full-process simulation and burst pressure prediction system for a weak stiffness mandrel composite material shell includes a design module, an optimization module, a simulation module, and a prediction module.

[0066] Among them, the design module is used to design residual stress tension regimes for fiber winding based on fiber winding layer stress theory; The optimization module is used to construct a finite element model of the shell winding process based on the designed tension regime. Guided by the balance between the safety of the propellant and the performance of the shell, the module iteratively optimizes the tension regime based on the simulation results and determines the stress field and strain field at the end of the winding after optimization. The simulation module is used to construct a finite element model of the shell curing process by taking the stress field and strain field at the end of the winding as a predefined field, and to calculate the stress field and strain field after the shell curing is completed. The prediction module is used to construct a finite element model for predicting the performance of the explosive-loaded shell by using the stress and strain fields after the shell has been cured as predefined fields. Through progressive damage analysis, it predicts the failure of the explosive-loaded shell and determines its maximum blast pressure.

[0067] This invention provides a terminal device comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve a corresponding method flow or function. The processor described in this embodiment can be used for the operation of a method for full-process simulation and explosive pressure prediction of a weak stiffness mandrel composite material shell, including: Based on the fiber winding layer stress theory, a residual stress tension regime for fiber winding is designed. According to the designed residual stress tension regime, a finite element model of the shell winding process is constructed. Guided by the balance between explosive charge safety and shell performance, the tension regime is iteratively optimized based on simulation results to determine the stress and strain fields at the end of the optimized winding process. Using the determined stress and strain fields at the end of the winding process as predefined fields, a finite element model of the shell curing process is constructed to calculate the stress and strain fields at the end of the shell curing process. Using the calculated stress and strain fields at the end of the shell curing process as predefined fields, a finite element model for predicting the performance of the explosive-loaded shell is constructed. Through progressive damage analysis, the failure of the explosive-loaded shell is predicted, and its maximum blast pressure is determined.

[0068] Please see Figure 10The terminal device is a computer device. In this embodiment, the computer device 60 includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the processor 61 executes the computer program 63, it implements the full-process simulation and burst pressure prediction method for the weak stiffness mandrel composite material shell in this embodiment. To avoid repetition, these details are not elaborated here. Alternatively, when the processor 61 executes the computer program 63, it implements the functions of each model / unit in the full-process simulation and burst pressure prediction system for the weak stiffness mandrel composite material shell in this embodiment. To avoid repetition, these details are not elaborated here.

[0069] Computer device 60 can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. Computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will understand that... Figure 10 This is merely an example of computer device 60 and does not constitute a limitation on computer device 60. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0070] The processor 61 may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0071] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on the computer device 60.

[0072] Furthermore, the memory 62 may include both internal storage units of the computer device 60 and external storage devices. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0073] Please see Figure 11 The terminal device is an electronic device 600, which is manifested in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including storage unit 620 and processing unit 610), a display unit 640, etc.

[0074] The storage unit stores program code, which can be executed by the processing unit 610 to perform the steps described in the method section of this specification according to various exemplary embodiments of the present invention. For example, the processing unit 610 can perform actions such as... Figure 1 The steps are shown in the figure.

[0075] Storage unit 620 may include a readable medium in the form of a volatile storage unit, such as random access memory (RAM) 6201 and / or cache memory 6202, and may further include a read-only memory (ROM) 6203.

[0076] Storage unit 620 may also include a program / utility 6204 having a set (at least one) program module 6205, such program module 6205 including but not limited to: operating system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0077] Bus 630 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the multiple bus structures.

[0078] Electronic device 600 can also communicate with one or more external devices 700 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 600, and / or with any device that enables electronic device 600 to communicate with one or more other computing devices (e.g., router, modem). This communication can be performed via input / output interface 650. Furthermore, electronic device 600 can also communicate with one or more networks (e.g., local area network, wide area network, and / or public network, such as the Internet) via network adapter 660. Network adapter 660 can communicate with other modules of electronic device 600 via bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0079] Example 4 This invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It is understood that the computer-readable storage medium here can include both built-in storage media in the terminal device and extended storage media supported by the terminal device; it can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor, which can be one or more computer programs (including program code). More specific examples of the computer-readable storage medium include: an electrical connection with one or more wires, a portable disk, a hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical fiber, portable compact disk read-only memory, optical storage device, magnetic storage device, or any suitable combination thereof.

[0080] Computer-readable storage media also include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium can also be any readable medium other than a readable storage medium that can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium can be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, radio frequency, etc., or any suitable combination thereof.

[0081] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0082] One or more instructions stored in a computer-readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the full-process simulation and burst pressure prediction method for the weak stiffness mandrel composite material shell in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor in the following steps: Based on the fiber winding layer stress theory, a residual stress tension regime for fiber winding is designed. According to the designed residual stress tension regime, a finite element model of the shell winding process is constructed. Guided by the balance between explosive charge safety and shell performance, the tension regime is iteratively optimized based on simulation results to determine the stress and strain fields at the end of the optimized winding process. Using the determined stress and strain fields at the end of the winding process as predefined fields, a finite element model of the shell curing process is constructed to calculate the stress and strain fields at the end of the shell curing process. Using the calculated stress and strain fields at the end of the shell curing process as predefined fields, a finite element model for predicting the performance of the explosive-loaded shell is constructed. Through progressive damage analysis, the failure of the explosive-loaded shell is predicted, and its maximum blast pressure is determined.

[0083] 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.

[0084] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0085] Winding process simulation Using the method of this invention, a residual stress tension regime of 7 winding layers (target residual stress 40 MPa) was designed. After simulation using the equivalent cooling method and the element life-death method, the maximum stress of the residual stress field of the shell was found to be 41.95 MPa. Figure 3 The maximum stress in the residual stress field of the propellant grain is only 0.0024 MPa. Figure 4 The strength is far below the safe strength of the propellant column (≥1MPa), which meets the safety requirements of the propellant column while achieving the balance of residual stress in each layer.

[0086] Residual stress of the propellant charge: maximum 0.0024MPa (radial in the middle section of the mandrel), minimum 0.0012MPa (axial at both ends), both below the safety strength of 0.5MPa, with a safety factor ≥208; Residual stress in the shell (Mises stress): maximum 41.95 MPa (outer surface of the 7th layer), minimum 34.74 MPa (inner surface of the 1st layer), with uniform interlayer stress gradient and no local concentration; Strain field data: After winding, the maximum radial strain of the shell is 0.00018, the axial strain is 0.00012, the maximum strain of the propellant is 0.0000048, and there is no plastic deformation.

[0087] Curing process simulation Introducing an unsteady temperature field and fixed increment step size control, the maximum overall residual stress of the shell after curing is 123 MPa. Figure 5The stress distribution is uniform, with no local stress concentration, accurately reproducing the stress evolution caused by the thermo-chemical-mechanical coupling during the curing stage.

[0088] Overall residual stress after curing (Mises stress): maximum 123 MPa (at the junction of the shell and the metal joint), minimum 1.86 MPa (at the center of the propellant grain). Stress evolution law: The residual stress in the winding stage accounts for 62% of the total stress after curing, and the newly added stress in the curing stage accounts for 38% (mainly caused by the mismatch between resin shrinkage and thermal expansion). Accuracy of field variable transfer: temperature field interpolation error ≤0.3℃, curing degree calculation error ≤1.2%, stress field transfer deviation ≤2.5%.

[0089] Explosion pressure prediction Progressive damage analysis based on the three-dimensional Hashin criterion was performed to capture the damage propagation process of layers 1, 3, 5, and 7 when the explosive casing failed. Figures 6 to 9 The final predicted maximum blast pressure was 21.3 MPa, with an error of only 2.4% compared to the subsequent actual blast test result (20.8 MPa).

[0090] Damage evolution data: 18.5 MPa: Tensile failure of the matrix occurred in the first layer (uvarm33=1.02), with a damaged area accounting for 5%; 20.3 MPa: Debonding of the fiber-matrix interface occurred in layers 3 and 5, with a damaged area accounting for 18%; 21.3 MPa: Tensile failure of the 7th fiber layer (uvarm33=1.207), damage to all layers is continuous, and the shell fails; Burst pressure: Predicted value 21.3 MPa; Actual validation data (3 parallel experiments): 20.8 MPa, 21.0 MPa, 21.2 MPa, with an average of 21.0 MPa and a prediction error of 1.4% (far lower than the 15%-20% error of traditional methods). Failure mode distribution: fiber tensile failure 60%, matrix tensile failure 25%, interlaminar shear failure 15%, which is completely consistent with the failure mechanism predicted by simulation.

[0091] In summary, this invention provides a full-process simulation and burst pressure prediction method for weak stiffness mandrel composite shells. It achieves digital integration across the entire process from fiber winding and resin curing to explosive detonation design, manufacturing, and evaluation. Through the chain-like transmission of stress-strain fields, it accurately characterizes the inheritance and evolution of residual stress in each process stage. Secondly, by introducing the equivalent cooling method, element life-death method, unsteady temperature field, and three-dimensional Hashin failure criterion, a high-fidelity multi-field coupled simulation model is established, significantly improving the accuracy of winding process simulation, curing stress calculation, and failure prediction. This invention pioneers an iterative optimization mechanism for tension regimes guided by propellant safety, automatically balancing the contradiction between mandrel protection and shell performance enhancement in the simulation environment, and outputting optimal process parameters. Applying this method, the burst pressure of the shell can be accurately predicted before physical manufacturing (e.g., predicted as 21.3 MPa in the example), quantitatively evaluating the impact of different process schemes, greatly reducing trial-and-error costs, shortening the R&D cycle, and providing a powerful theoretical tool and design basis for the process optimization and reliability design of integrated propellant-coated shells for solid rocket engines.

[0092] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0093] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0094] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0095] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0096] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0097] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0098] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random-access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0099] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus, and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0100] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0101] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0102] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for full-process simulation and burst pressure prediction of a weak stiffness mandrel composite material shell, characterized in that, Includes the following steps: S1. Based on the fiber winding layer stress theory, design the residual stress tension regime of fiber winding, etc. S2. Based on the residual stress tension regime of fiber winding designed in step S1, construct a finite element model of the shell winding process. Guided by the balance between the safety of the propellant and the performance of the shell, iteratively optimize the tension regime based on the simulation results to determine the stress field and strain field at the end of the optimized winding. S3. Using the stress field and strain field determined in step S2 after the winding is completed as a predefined field, construct a finite element model of the shell curing process, and calculate the stress field and strain field after the shell curing is completed. S4. Using the stress field and strain field obtained in step S3 after the shell curing is completed as a predefined field, construct a finite element model for predicting the performance of the explosive shell. Through progressive damage analysis, predict the failure of the explosive shell and determine its maximum blast pressure.

2. The method for full-process simulation and burst pressure prediction of weak stiffness mandrel composite material shell according to claim 1, characterized in that, The weak stiffness mandrel is a propellant grain.

3. The method for full-process simulation and burst pressure prediction of weak stiffness mandrel composite material shell according to claim 1, characterized in that, In step S1, based on the formula for residual stress of the fiber winding layer, and with the preset residual stress value of the winding layer as the target, an equal residual stress tension regime is designed.

4. The method for full-process simulation and burst pressure prediction of weak stiffness mandrel composite material shell according to claim 1, characterized in that, Step S2 includes: S201. Based on the actual geometric dimensions and material performance parameters, establish a three-dimensional model of the composite material shell, including the fiber winding layer, metal joint, insulation layer, lining layer, and propellant core mold. S202. The equivalent cooling method is adopted to simulate the prestress generated by winding tension through the temperature field. S203. The progressive simulation of layer-by-layer contact activation is achieved by using the unit dead-live method, and the prestress of the winding layer is applied in combination with the equivalent cooling method. S204. Based on the simulation output of the finite element model of the shell winding process, compare the maximum stress of the propellant with the safe strength of the propellant, iteratively update the tension regime until the optimized tension regime corresponding to the maximum remaining stress of the winding layer under the safe strength of the propellant is obtained, and determine the stress field and strain field under this state.

5. The method for full-process simulation and burst pressure prediction of weak stiffness mandrel composite material shell according to claim 4, characterized in that, In step S202, the equivalent cooling method continuously changes the initial temperature field within the i-th winding layer, so that the simulated output residual stress of the winding layer reaches the predetermined target residual stress value.

6. The method for full-process simulation and burst pressure prediction of weak stiffness mandrel composite material shell according to claim 1, characterized in that, In step S3, the finite element model of the shell curing process uses the stress field and strain field at the end of the winding as the predefined fields, introduces unsteady temperature field boundary conditions and adopts a fixed incremental step size control strategy to calculate and output the stress field and strain field after the shell curing is completed.

7. The method for full-process simulation and burst pressure prediction of weak stiffness mandrel composite material shell according to claim 1, characterized in that, In step S4, the finite element model for predicting the performance of the drug-loaded shell adopts the three-dimensional Hashin failure criterion to characterize the fiber-dominated failure and matrix-dominated failure of the composite material layer.

8. The method for full-process simulation and burst pressure prediction of weak stiffness mandrel composite material shell according to claim 7, characterized in that, The three-dimensional Hashin failure criterion includes criteria for four failure modes: fiber tensile failure, fiber compression failure, matrix tensile failure, and matrix compression failure.

9. The method for full-process simulation and burst pressure prediction of weak stiffness mandrel composite material shell according to claim 1, characterized in that, In step S4, the stress and strain fields after the curing of the explosive casing are used as predefined fields. By performing progressive damage analysis on the finite element model for predicting the performance of the explosive casing, the maximum internal pressure when the explosive casing fails is obtained as the maximum blast pressure.

10. A full-process simulation and burst pressure prediction system for a weak stiffness mandrel composite material shell, characterized in that, include: The design module is used to design residual stress tension regimes for fiber winding based on the fiber winding layer stress theory. The optimization module is used to construct a finite element model of the shell winding process based on the designed tension regime. Guided by the balance between the safety of the propellant and the performance of the shell, the module iteratively optimizes the tension regime based on the simulation results and determines the stress field and strain field at the end of the winding after optimization. The simulation module is used to construct a finite element model of the shell curing process by taking the stress field and strain field at the end of the winding as a predefined field, and to calculate the stress field and strain field after the shell curing is completed. The prediction module is used to construct a finite element model for predicting the performance of the explosive-loaded shell by using the stress and strain fields after the shell has been cured as predefined fields. Through progressive damage analysis, it predicts the failure of the explosive-loaded shell and determines its maximum blast pressure.

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