Solid rocket engine winding shell end socket stress visualization method

Abstract

The invention discloses a solid rocket engine winding shell end socket stress visualization method, and belongs to the technical field of solid rocket engines. The method comprises the steps that a finite element simulation model of the solid rocket engine winding shell end socket structure is constructed, mechanical property simulation analysis is conducted, and stress state analysis result data are obtained and subjected to post-processing; reading post-processed stress state analysis result data, and based on a principal stress trace theory, using a cylindrical coordinate system as a tracking basis, and using a dichotomy to control a tracking step length to generate a single principal stress line; the density generated by the principal stress line is regulated and controlled based on the spacing control parameters; and regulating and controlling the tracking linetype of the principal stress line based on the linetype control parameters, and drawing a stress visual image. According to the method, the problem that a traditional fiber winding process and a thin-layer solid structure lack process guiding significance on a stress visualization result is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of solid rocket engines, and in particular relates to a method for visualizing stress of a solid rocket engine wound casing head. Background Art

[0002] As the main load-bearing structure of the engine, the solid rocket engine casing has a key impact on the overall performance and safety of the rocket. With the development of industrial technology, the design and manufacturing technology of solid rocket engine casings have been continuously improved. The fiber-wound composite casing head structure has become the mainstream direction of casing design with its excellent material structural properties and pressure resistance and corrosion resistance. In the design process of the casing head, simulation stress analysis is the most critical reference tool. Traditional stress analysis methods mainly rely on theoretical calculations and empirical formulas, but with the improvement of computing power, through finite element analysis (FEA), designers can obtain detailed stress distribution information of the casing under various load conditions, thereby ensuring the safety and reliability of the design. The development of modern visualization technology makes the display of stress analysis results more intuitive. Through three-dimensional modeling and graphics rendering technology, complex stress distribution can be intuitively displayed in the form of color, shape, etc. There are many finite element simulation commercial software on the market (such as ANSYS, ABAQUS, etc.) that provide model stress analysis and visualization functions. These tools integrate powerful computing and graphics processing capabilities, and users can obtain detailed stress distribution diagrams through simple operations.

[0003] The existing commercial finite element simulation software mainly relies on finite element analysis cloud diagrams for characterization and analysis of the stress distribution of the head structure, which is difficult to provide a direct reference for the design of the shell head structure, resulting in unclear optimization direction of the process parameters of the shell head winding design, large uncertainty in single optimization, and long total optimization time. In addition, the existing open source stress direction visualization program (published by Wang Junpeng on GitHub) usually processes data based on .stress format files, while conventional commercial finite element simulation software, such as ABAQUS, cannot directly output .stress format files, requiring complex data processing, complicated procedures, and bringing a large operational burden to users. At the same time, this stress direction visualization method is based on grid node stress, and the principal stress traces (PSLs) are used to characterize the maximum stress direction at each node in the object when subjected to external forces. However, this method is not suitable for thin-layer solid structures, and it is difficult to completely draw the principal stress traces of the overall model, and it is impossible to clearly characterize the stress direction of the model.

[0004] Therefore, the present invention proposes a stress visualization method for a solid rocket engine wound case head based on principal stress traces, especially for the influence of fiber winding process and thin-layer solid structure on stress visualization in the solid rocket engine wound case head structure. At the same time, the human-computer interaction mode is optimized, and the visualization display of stress lines is adjusted by controlling parameters to reduce the burden on operators. Summary of the invention

[0005] Technical issues to be solved:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a stress visualization method for a solid rocket engine wound casing head, which solves the problem that traditional fiber winding processes and thin-layer solid structures lack process guidance for stress visualization results through a unique stress data post-processing process, a principal stress line generation and density control mechanism, and a linear trajectory control technology.

[0007] The technical solution of the present invention is: a method for visualizing the stress of a solid rocket engine winding casing head, and the specific steps are as follows:

[0008] Construct a finite element simulation model of the solid rocket engine wound casing head structure, perform mechanical performance simulation analysis, obtain stress state analysis result data and perform post-processing;

[0009] After reading the processed stress state analysis result data, based on the principal stress trace theory, with the cylindrical coordinate system as the tracking basis, the dichotomy method is used to control the tracking step size to generate a single principal stress line;

[0010] The density of principal stress line generation is regulated based on spacing control parameters;

[0011] The tracing line type of the principal stress line is regulated based on the line type control parameters, and a stress visualization image is drawn.

[0012] A further technical solution of the present invention is: the post-processing method of the stress state analysis result data is:

[0013] Simplifying the stress state analysis result data, that is, outputting the unit integration point stress and node coordinate data of the shell sub-structure to be processed from the simulation results, and storing them in a general format data storage file;

[0014] Read the stress magnitude of the integration point in the cone shell reduced integration unit from the data storage file, set each row as a unit in the order of unit index number, and store it as a stress matrix in the order of natural output of the software. At this time, the row number index of the matrix is ​​the arrangement order number of the unit;

[0015] Read the node index data and node coordinate data of the cone shell reduced integration unit from the data storage file, set each row as a unit in the order of the unit node coordinates x, y, z, and store it as a node matrix in the order of the natural output of the software. At this time, the row number index of the matrix is ​​the number index of the node; set each row as a unit in the order of the index number of the node in the unit, and store it as a unit node index matrix in the order of the natural output of the software. At this time, the row number index of the matrix is ​​the arrangement order number of the unit;

[0016] Based on the number of units, a loop is traversed to extract the elements in the stress matrix and arrange them as a tensor matrix. The eigenvalues ​​and eigenvectors of the matrix are solved by the QR eigenvalue solution. They are arranged according to size and stored as a matrix in the order of eigenvalue and eigenvector space components. At this time, each row in the matrix is ​​the magnitude and direction of the principal stress of the unit integration point indexed by the row number.

[0017] A further technical solution of the present invention is: the specific operation of post-processing the stress state analysis result data is:

[0018] Use finite element simulation software to complete the simulation calculation of the solid rocket motor winding shell head structure;

[0019] Output model stress state data, store and output in the software common output format;

[0020] Load the model stress state data in the program;

[0021] Post-process the stress state analysis result data;

[0022] Output post-processed data and save it as a common format data storage file.

[0023] A further technical solution of the present invention is: the data storage file includes the number and coordinates of nodes, the number and index matrix of units, the position, value and direction of loads, the position and method of constraints, the magnitude and direction vector of principal stresses.

[0024] A further technical solution of the present invention is: the method for generating a single principal stress line is:

[0025] Select an element, use its integration point as the seed point, and start tracing its maximum or minimum principal stress line from this point based on the stress tracing scheme;

[0026] When the generation of the principal stress line of a seed point is completed, the candidate point closest to the initial seed point is selected as the new seed point according to the set stress trajectory distance parameter;

[0027] Repeat the above steps until all candidate points are tracked, that is, the integration of the principal stress lines based on the stress tensor field is completed.

[0028] A further technical solution of the present invention is: the stress tracking solution is a method for generating a single stress trajectory;

[0029] Randomly select or specify a unit as a seed to trace stress lines;

[0030] Set the step size from the first element along the principal stress direction to the next element;

[0031] After extending one step along the principal stress direction, it reaches the second element;

[0032] Repeat the above steps for the second unit until it reaches the boundary.

[0033] A further technical solution of the present invention is: the method of controlling the tracking step length using the bisection method based on the cylindrical coordinate system is:

[0034] Determine cell e i The current point P in i The spatial coordinate position of the unit is read, the number of the unit integration point is read and the principal stress direction of the unit integration point is extracted. The principal stress direction is converted into the cylindrical coordinate system. Integrate the derivative to obtain the distance P i Point, along Direction, arc length is the new test integration point P of step length x i+1 , determine whether it is in the original cell e i In the range of i Does not contain P i+1 , you need to determine the cell e i+1 ;

[0035] Define cell e i The cells next to each other are adjacent cells, and P is further tested. i+1 Is it located in e i Any adjacent cell e adj If P i+1 Not in e i or e adj Inside, reduce the step size x by bisection;

[0036] Until P i+1 Located in i or e adj Then the integration process starts at the integration point P i+1 and contains P i+1 Cell e i+1 restart.

[0037] A further technical solution of the present invention is: the method for regulating the density of principal stress line generation based on the spacing control parameter is:

[0038] Set the control parameter for regulating the stress line spacing to m, which is the minimum number of spacing units between stress lines;

[0039] The control parameter m is used as the minimum number of spacing units between stress lines, and the space surrounded by m units around the first generated stress line is regarded as the "empty zone";

[0040] The cell closest to the seed outside the “empty zone” is used as the second seed to start tracing the next stress line;

[0041] Repeat the above steps until stress lines of all parts are drawn.

[0042] A further technical solution of the present invention is: the method for regulating the tracking line type of the principal stress line based on the line type control parameter is:

[0043] Set the linear control parameter for regulating the frequency of the pattern to n, which is the number of unit intervals between adjacent units in the stress line tracing process;

[0044] According to the linear control parameters of the seeding frequency, all cells within the area enclosed by the next cell with a spacing of n cells from the original cell are defined as adjacent cells, and the number of cell intervals selected as seeding point cells is controlled;

[0045] Stress line tracing is performed according to the method of generating a single principal stress line to draw a new stress line.

[0046] An electronic device comprises at least one processor and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for visualizing the stress of a solid rocket motor wound casing head.

[0047] Beneficial Effects

[0048] The beneficial effects of the present invention are as follows: the present invention proposes a stress visualization method for the head of a solid rocket engine wound shell based on the principal stress trace, and effectively solves the problem that stress visualization in the traditional fiber winding process lacks process guidance through a unique stress data post-processing process, a principal stress line generation and density control mechanism, and a linear trajectory control technology. Compared with the existing patents, the present invention simplifies the data processing process and improves the compatibility and processing efficiency of the data; the eigenvalue solution is used to accurately calculate the principal stress direction, and the binary step control is introduced in the cylindrical coordinate system to ensure the consistency and accuracy of the stress line in the high curvature and thin-layer shell structure, and solves the problem of stress line fracture when stress tracing to the thin layer boundary for the composite shell thin-layer structure in the existing invention. In addition, through the dynamic adjustment of the spacing and linear parameters, the optimization of the density and arrangement of the stress lines is achieved, and the clarity and process guidance value of the stress visualization image are significantly improved. The standardized and efficient data processing process of the method is seamlessly integrated with the finite element simulation software, providing a systematic and reusable visualization tool, significantly enhancing the guidance and efficiency of process optimization and engineering design, and showing significant creativity and novelty.

[0049] Compared with the existing stress line visualization results, Fig.10 As shown, the traditional fiber winding process lacks process guidance significance for stress visualization results, and the existing stress tracing method is prone to stress line fracture in high curvature and thin-layer structures. At the same time, the required data processing is complex, and only specific .stress format files can be read as data input, lacking standardization and efficiency. The present invention provides a systematic and standardized stress visualization method, which uses the principal stress trace as a processing reference for composite shells, thereby enhancing the process guidance significance of the results. The accuracy and consistency of stress lines are ensured by the eigenvalue solution and the binary step control based on the cylindrical coordinate system. Optimized data processing flow and stress line density control, such as Figure 7 As shown in the figure, the processing efficiency and image quality are improved. The stress distribution of the shell head structure is fully covered, such as Fig. 9 As shown, more accurate process optimization and design improvement are supported. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The data pre-processing flow chart for realizing stress visualization in the present invention.

[0051] Figure 2 This is a flow chart of post-processing of stress state data of the present invention.

[0052] Figure 3 This is a flow chart for converting input files of the stress visualization program of the present invention.

[0053] Figure 4 This is a stress visualization flow chart of the present invention.

[0054] Figure 5 A flow chart is generated for the single stress line trajectory of the present invention.

[0055] Figure 6 Search step size control tracking flow chart for the present invention.

[0056] Figure 7 This is a visualization comparison diagram of stress lines controlled by parameters of the present invention.

[0057] Figure 8 Visualization of stress lines for a homogeneous material shell.

[0058] Fig. 9 Schematic diagram of the operation steps of an embodiment of the present invention.

[0059] Fig.10 This is a comparison diagram of the effects of the present invention and the existing stress visualization on a composite material thin-wall shell structure. DETAILED DESCRIPTION

[0060] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0061] Based on the problems that the stress visualization method for the solid rocket engine wound shell head structure used in the prior art has difficulty in data post-processing, no process guidance for the stress visualization of the fiber winding process and the thin layer solid structure, and complex human-computer interaction operation, the present invention provides a solid rocket engine wound shell head stress visualization method based on the principal stress trace, and the specific steps are as follows:

[0062] Step 1: Construct a finite element simulation model of the solid rocket engine wound shell head structure, perform mechanical performance simulation analysis, obtain stress state analysis result data and perform post-processing;

[0063] Step 2: Read the stress state analysis result data after completion, based on the principal stress trace theory, with the cylindrical coordinate system as the tracking basis, use the dichotomy method to control the tracking step size, and generate a single principal stress line;

[0064] Step 3: Regulate the density of principal stress line generation based on the spacing control parameter;

[0065] Step 4: Adjust the tracing line type of the principal stress line based on the line type control parameters and draw a stress visualization image.

[0066] The present invention can be used to realize the visualization display of the principal stress trajectories of different areas and winding layers of the head, obtain the stress distribution trajectory diagram of the head structure, and analyze the influence of winding process parameters such as different areas, winding line types, yarn sizes, winding angles and different head reinforcement processes on the stress distribution of the head accordingly, so as to provide guidance and direct reference for the design, manufacture, optimization and reinforcement of the head structure of the solid rocket engine winding casing.

[0067] The above technical solution is further described below in conjunction with the accompanying drawings and specific embodiments. The intermediate transition parameters, functions, and matrices designed in the following steps are all examples, including but not limited to the following naming methods:

[0068] Reference Figure 1 As shown, this embodiment includes a pre-processing process for stress visualization data of a solid rocket engine wound casing head structure. The present invention is connected to commonly used commercial finite element analysis software, such as ABAQUS. The commonly used output format file of the commonly used commercial software is used as the initial file, and the output data is post-processed, and finally organized into a universal format data storage file as an input file for realizing stress visualization. This embodiment takes ABAQUS finite element analysis software as an example as simulation analysis software. Take its commonly used output format file (.rpt format file) as an example as a data output file. Take the universal format data storage file, .stress format file as an example as the output file of the stress visualization solution. The specific steps are as follows:

[0069] Step 1: Use ABAQUS finite element simulation commercial software to complete the simulation calculation of the solid rocket motor wound case head structure.

[0070] Step 2: Output the model stress state data and save it as a .rpt format file.

[0071] Step 3: Load the model stress state data in the program.

[0072] Step 4: Post-process the stress state data.

[0073] Step 5: Output the post-processed data as a .stress format file.

[0074] Reference Figure 2As shown, the stress state data is post-processed. The stress state data output from the commercial software is usually the magnitude of the principal stress of the node and unit integration point and the magnitude of the Cartesian stress. In this embodiment, the direction vector of the principal stress of each unit integration point in the Cartesian coordinate is also required. Therefore, it is necessary to reprocess the stress state data output from the commercial software, and use the eigenvalue method to solve the stress tensor matrix of each unit integration point to calculate the stress data that needs to be input. This embodiment takes the commercial software ABAQUS as an example to simulate and output data, and the output data file format takes the .rpt format as an example. The specific steps are as follows:

[0075] Step 1: Read the element integration point stress from the .rpt format file and store it as a stress matrix.

[0076] Step 2: Read the unit node index data and node coordinate data from the .rpt format file and store them as eleids and nodes matrices.

[0077] Step 3: Loop through the stress matrix, output the stress data of each unit integration point as a p matrix, and use the eigenvalue solution to obtain the magnitude and direction of the three principal stresses at each unit integration point.

[0078] Reference Figure 3 As shown, the output post-processing data is a general format data storage file. This embodiment takes the .stress format file as an example and uses MATLAB software for programming. Since the .stress format file has its fixed format and corresponding syntax, the processed data is output according to the file format for subsequent calls. The specific steps are as follows:

[0079] Step 1: Create a .stress format file and open it, output dimension search keywords, and output unit search keywords.

[0080] Step 2: Output node search keywords, output node quantity, and output node coordinate data.

[0081] Step 3: Output the unit search keywords, output the number of units, and output the unit index data under the new node matrix based on the unit index matrix.

[0082] Step 4: Output node load search keywords and output node load data.

[0083] Step 5: Output node constraint search keywords and output node constraint data.

[0084] Step 6: Output Cartesian stress search keywords, and output the three principal stress magnitudes and principal stress direction vector data.

[0085] Step 7: Close the .stress format file.

[0086] The specific steps of the post-processing method of the stress state analysis result data are as follows:

[0087] Step 1: simplify the stress state analysis result data, that is, output the unit integration point stress and node coordinate data of the shell sub-structure to be processed from the simulation results, and store them in a general format data storage file;

[0088] Step 2: Read the stress magnitude of the integration point in the conical shell reduced integration unit from the data storage file, set each row as a unit in the order of the unit index number, and store it as a stress matrix in the order of the natural output of the software. At this time, the row number index of the matrix is ​​the arrangement order number of the unit;

[0089] Step 3: Read the node index data and node coordinate data of the cone shell reduced integration unit from the data storage file, set each row as a unit in the order of the unit node coordinates x, y, z, and store it as a node matrix in the order of the natural output of the software. At this time, the row number index of the matrix is ​​the node number index; set each row as a unit in the order of the index number of the node in the unit, and store it as a unit node index matrix in the order of the natural output of the software. At this time, the row number index of the matrix is ​​the arrangement order number of the unit;

[0090] Step 4: Loop through the elements based on the number of units, extract the elements in the stress matrix and arrange them as a tensor matrix. Use the QR eigenvalue solution to solve the eigenvalues ​​and eigenvectors of the matrix, arrange them according to size and store them as a matrix in the order of eigenvalue and eigenvector space components. At this time, each row in the matrix is ​​the magnitude and direction of the principal stress of the unit integration point indexed by the row number.

[0091] Reference Figure 4 As shown in the figure, the stress visualization method based on the principal stress trace is based on the generation of a single stress trace. In view of the influence of the thin layer structure in the shell head structure on the normal principal stress trace, the stress visualization method based on the principal stress trace is realized by selecting the unit integration point and tracing the unit by unit.

[0092] Specifically, the method for generating a single principal stress line in step 2 includes the following steps:

[0093] Step 1: Select an element and use its integration point as the seed point. Start tracing its maximum or minimum principal stress line from this point based on the stress tracing scheme.

[0094] Step 2: When the generation of the principal stress line of a seed point is completed, the candidate point closest to the initial seed point is selected as the new seed point according to the set stress trajectory distance parameter.

[0095] Step 3: Repeat step 1 until no candidate points are available, and achieve the integration of principal stress lines based on the stress tensor field.

[0096] Reference Figure 5 As shown in the figure, the stress tracking scheme is a method for generating a single stress trajectory: first, randomly select or specify a unit in the model as a seed to track the initial point of the stress line, set a step length along the principal stress direction from the first unit, and the step length ends at the next unit; then extend along the principal stress direction for a step length to reach the second unit; and repeat the operation in the second unit until the unit at the model boundary. The specific steps are as follows:

[0097] Step 1: Randomly select or specify a unit as a seed unit to trace the stress line.

[0098] Step 2: Set the tracking step size along the principal stress direction from the first element.

[0099] Step 3: Extend one step along the principal stress direction to reach the second element.

[0100] Step 4: Repeat steps 2 and 3 for the second unit until the boundary is reached.

[0101] Reference Figure 6 As shown, the method of using the cylindrical coordinate system as the tracking basis and using the dichotomy method to control the tracking step size: Since the present invention is aimed at a composite material wound shell, the model is approximately an axisymmetric model. The existing stress tracking method is very easy to track to the boundary in a high curvature and thin layer structure. Therefore, the present invention uses the cylindrical coordinate system dichotomy method to track stress to ensure the continuity of the stress line. In the stress tracking process, take this as an example: take the controllable variable x as the step size, and move the principal stress line from the cell e i The current point P in i Integrate to a new point P i+1 The specific steps are as follows:

[0102] Step 1: Determine cell e i The current point P in i The spatial coordinate position of the unit is read, the number of the unit integration point is read and the principal stress direction of the unit integration point is extracted. The principal stress direction is converted into the cylindrical coordinate system. Integrate the derivative to obtain the distance P i Point, along Direction, arc length is the new test integration point P of step length x i+1 , determine whether it is in the original cell e i In the range of i Does not contain P i+1 , you need to determine the cell e i+1 ;

[0103] Step 2: Example definition cell e i The cells next to each other are adjacent cells, and P is further tested. i+1 Is it located in e i Any adjacent cell e adj If P i+1 Not in e i or e adj Inside, reduce the step size x by bisection;

[0104] Step 3: Until P i+1 Located in i or e adj Then the integration process starts at the integration point P i+1 and contains P i+1 Cell e i+1 restart.

[0105] Reference Figure 7 As shown, the method of regulating the density of the main stress line generation based on the spacing control parameter. The present invention sets three control parameters, which directly affect the angle of stress line tracking by directly changing the seed density of the seed unit; directly affect the distance between stress lines by directly changing the production spacing of the stress trace; and directly affect the thickness of the stress line by directly changing the relative width of the image stress line. Thus, a multi-angle, multi-level, and diversified display effect is achieved.

[0106] The specific steps are as follows:

[0107] Step 1: Set the frequency control parameters of the cloth.

[0108] Step 2: Control the number of intervals between the elements selected at the seeding point.

[0109] Step 3: Set the control parameters for adjusting the stress line spacing.

[0110] Step 4: According to the control parameters, the space with a specified distance around the first generated stress line is used as an "empty zone".

[0111] Step 5: Use the cell closest to the seed outside the "empty zone" as the second seed and start tracing the next stress line.

[0112] Step 6: Repeat steps 2 and 3 until stress lines of all parts are drawn.

[0113] Step 7: Set the stress line width control parameters.

[0114] Step 8: Based on the control parameters in step 3, the scaling factor of the stress line width is calculated through the "empty band" parameter.

[0115] Reference Figure 8As shown, stress visualization based on stress traces is implemented for a homogeneous material shell. In this embodiment, a shell structure made of homogeneous aluminum material is used and analyzed using stress visualization technology.

[0116] This embodiment uses a shell size of φ480mm as an example, and the specific steps are as follows:

[0117] Step 1: Create a 3D model of the shell and apply predetermined load conditions to the model.

[0118] Step 2: Use finite element analysis software to perform stress analysis on the model and obtain the stress distribution data of the shell under internal pressure load conditions.

[0119] Step 3: Post-process the stress state analysis result data of the homogeneous material shell head structure to obtain the magnitude and direction of the principal stress at the unit integration point.

[0120] Step 4: Read the data and generate a single principal stress line based on the principal stress trace theory and the bisection method to control the tracking step size.

[0121] Step 5: Generate all principal stress lines based on control parameter regulation.

[0122] Step 6: Based on the control parameter regulation, the user can finally control the display effect of the stress line by adjusting the parameters.

[0123] Reference Fig. 9 As shown, the specific operation steps of the method for visualizing the stress of the solid rocket engine winding shell head based on the principal stress trace in this embodiment are as follows:

[0124] According to the specific operation methods described in the above decomposed embodiments, taking a φ480mm shell as an example, the fiber winding angle is 23.5°, and the shell is wound with 2 longitudinal winding layers and 4 circumferential winding layers, wherein each longitudinal winding layer consists of two layers along the radial winding angle of the shell meridian plane. The specific implementation steps are as follows:

[0125] Step 1: Reference Fig. 9 In Figure a, a three-dimensional model of the shell is established based on the finite element analysis commercial software, and predetermined load conditions are applied to the model.

[0126] Step 2: Reference Fig. 9 Figure b: The stress analysis of the model is performed using finite element analysis software.

[0127] Step 3: Reference Fig. 9 Figure c in the middle obtains the stress distribution data of the shell under internal pressure load conditions.

[0128] Step 4: Post-process the stress state analysis result data of the homogeneous material shell head structure. Obtain the magnitude and direction of the principal stress at the unit integration point. Fig. 9 In Figure d, for the convenience of display, the principal stress direction distribution diagram of the unit integration point can be output here for reference and comparison.

[0129] Step 5: Read the data, and generate a single principal stress line based on the principal stress trace theory and the bisection method to control the tracking step in the cylindrical coordinate system.

[0130] Step 6: Generate all principal stress lines based on the stress line spacing control parameter regulation.

[0131] Step 7: Reference Fig. 9 In Figure e, based on the stress line type control parameter regulation, the user can ultimately control the display effect of the stress line by adjusting the parameters.

[0132] Reference Fig.10 As shown, this embodiment uses the existing stress visualization method as a comparison, selects a solid rocket engine wound shell, that is, a thin-walled structure, and adopts a conical shell unit model to compare the stress visualization effect.

[0133] It can be clearly seen that the images of the existing stress visualization method show obvious stress line fracture, discontinuity, sparseness and other states, and it is impossible to provide guidance or optimization on the processing technology based on its stress state. The stress state display is not intuitive, which means that the existing stress visualization method is not suitable for the thin-walled structure of the composite shell, and its restrictions on input files make it impossible for some commercial software to directly use its data interface.

[0134] The image of the stress visualization method of the present invention in this embodiment shows obvious continuity of stress lines, appropriate density, and integrity of the coating around the axisymmetric shell. It can provide guidance and optimization for the winding process, laying process, etc. of the composite shell, and can intuitively display its stress state. At the same time, it optimizes the data structure and can be compatible with the data output of various commercial software.

[0135] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A method for visualizing stress of a solid rocket engine wound casing head, characterized in that The specific steps are as follows: Construct a finite element simulation model of the solid rocket engine wound casing head structure, perform mechanical performance simulation analysis, obtain stress state analysis result data and perform post-processing; After reading the processed stress state analysis result data, based on the principal stress trace theory, with the cylindrical coordinate system as the tracking basis, the dichotomy method is used to control the tracking step size to generate a single principal stress line; The density of principal stress line generation is regulated based on spacing control parameters; The tracing line type of the principal stress line is regulated based on the line type control parameters, and a stress visualization image is drawn.

2. According to claim 1, a method for visualizing stress of a solid rocket motor wound casing head, characterized in that: The post-processing method of the stress state analysis result data is: Simplifying the stress state analysis result data, that is, outputting the unit integration point stress and node coordinate data of the shell sub-structure to be processed from the simulation results, and storing them in a general format data storage file; Read the stress magnitude of the integration point in the cone shell reduced integration unit from the data storage file, set each row as a unit in the order of unit index number, and store it as a stress matrix in the order of natural output of the software. At this time, the row number index of the matrix is ​​the arrangement order number of the unit; Read the node index data and node coordinate data of the cone shell reduced integration unit from the data storage file, set each row as a unit in the order of the unit node coordinates x, y, z, and store it as a node matrix in the order of the natural output of the software. At this time, the row number index of the matrix is ​​the number index of the node; set each row as a unit in the order of the index number of the node in the unit, and store it as a unit node index matrix in the order of the natural output of the software. At this time, the row number index of the matrix is ​​the arrangement order number of the unit; Based on the number of units, a loop is traversed to extract the elements in the stress matrix and arrange them as a tensor matrix. The eigenvalues ​​and eigenvectors of the matrix are solved by the QR eigenvalue solution. They are arranged according to size and stored as a matrix in the order of eigenvalue and eigenvector space components. At this time, each row in the matrix is ​​the magnitude and direction of the principal stress of the unit integration point indexed by the row number.

3. According to claim 2, a method for visualizing stress of a solid rocket engine wound casing head, characterized in that: The specific post-processing operations of the stress state analysis result data are as follows: Use finite element simulation software to complete the simulation calculation of the solid rocket motor winding shell head structure; Output model stress state data, store and output in the software common output format; Load the model stress state data in the program; Post-process the stress state analysis result data; Output post-processed data and save it as a common format data storage file.

4. According to claim 2, a method for visualizing stress of a solid rocket motor wound casing head, characterized in that: The data storage file includes the number and coordinates of nodes, the number and index matrix of elements, the position, value and direction of loads, the position and method of constraints, the magnitude and direction vector of principal stresses.

5. According to claim 2, a method for visualizing stress of a solid rocket motor wound casing head, characterized in that: The method for generating a single principal stress line is: Select an element, use its integration point as the seed point, and start tracing its maximum or minimum principal stress line from this point based on the stress tracing scheme; When the generation of the principal stress line of a seed point is completed, the candidate point closest to the initial seed point is selected as the new seed point according to the set stress trajectory distance parameter; Repeat the above steps until all candidate points are tracked, that is, the integration of the principal stress lines based on the stress tensor field is completed.

6. A method for visualizing stress of a solid rocket motor wound casing head according to claim 5, characterized in that: The stress tracking scheme is a method for generating a single stress trajectory; Randomly select or specify a unit as a seed to trace stress lines; Set the step size from the first element along the principal stress direction to the next element; After extending one step along the principal stress direction, it reaches the second element; Repeat the above steps for the second unit until it reaches the boundary.

7. A method for visualizing stress of a solid rocket motor wound casing head according to claim 6, characterized in that: The method of using the cylindrical coordinate system as the tracking basis and using the dichotomy method to control the tracking step size is: Determine cell e i The current point P in i The spatial coordinate position of the unit is read, the number of the unit integration point is read and the principal stress direction of the unit integration point is extracted. The principal stress direction is converted into the cylindrical coordinate system. Integrate the derivative to obtain the distance P i Point, along Direction, arc length is the new test integration point P of step length x i+1 , determine whether it is in the original cell e i In the range of i Does not contain P i+1 , you need to determine the cell e i+1 ; Define cell e i The cells immediately surrounding it are adjacent cells, and P is further tested. i+1 Is it located in e i Any adjacent cell e adj If P i+1 Not in e i or e adj Inside, reduce the step size x by bisection; Until P i+1 Located in i or e adj Then the integration process starts at the integration point P i+1 and contains P i+1 Cell e i+1 restart.

8. A method for visualizing stress of a solid rocket motor wound casing head according to claim 7, characterized in that: The method for regulating the density of principal stress line generation based on the spacing control parameter is: Set the control parameter for regulating the stress line spacing to m, which is the minimum number of spacing units between stress lines; The control parameter m is used as the minimum number of cells between stress lines, and the space surrounded by m cells around the first generated stress line is used as the "empty zone"; The cell closest to the seed outside the "empty zone" is used as the second seed to start tracing the next stress line; Repeat the above steps until stress lines of all parts are drawn.

9. A method for visualizing stress of a solid rocket motor wound casing head according to claim 8, characterized in that: The method for regulating the tracking line type of the principal stress line based on the line type control parameter is: Set the linear control parameter for regulating the frequency of the pattern to n, which is the number of unit intervals between adjacent units in the stress line tracing process; According to the linear control parameters of the seeding frequency, all cells within the area enclosed by the next cell with a spacing of n cells from the original cell are defined as adjacent cells, and the number of cell intervals selected as seeding point cells is controlled; Stress line tracing is performed according to the method of generating a single principal stress line to draw a new stress line.

10. An electronic device, characterized in that: It includes at least one processor and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for visualizing the stress of the solid rocket engine wound casing head as described in any one of claims 1 to 9.

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