A joint simulation method for launch vehicle pipelines

Abstract

The present invention provides a launch vehicle pipeline joint simulation method, which at least includes the following steps: drawing a three-dimensional model of an engine system, a structural system and a pipeline system; performing joint simulation on the engine system, the structural system and the pipeline system, and obtaining the stress distribution of the structure under a static load condition; calculating the static load condition of the pipeline, a bracket and a boundary flange; calculating the dynamic load condition of the pipeline, the bracket and the boundary flange; obtaining the dynamic load after performing a comprehensive evaluation on the static load condition and the dynamic load condition; analyzing the strength of the dynamic load condition according to the dynamic load; performing a strength evaluation according to the stress distribution of the structure under the static load condition and the strength of the dynamic load condition, and if the strength meets expectations, terminating the joint simulation of the corresponding pipeline and related interfaces.

Description

Technical Field

[0001] The invention relates to the technical field of launch vehicle pipelines, in particular to a launch vehicle pipeline joint simulation method. Background Art

[0002] During the development phase, pipeline strength analysis is required for launch vehicle pipelines. The input conditions for pipeline analysis include pressure, temperature, deformation, and vibration conditions. The deformation is mainly provided by the cabin structure and the engine. The traditional design idea is that the cabin structure system and the engine system give the deformation of the pipeline docking position according to their own working conditions, ignoring the impact after the pipeline is installed. At the same time, when analyzing the pipeline, the structure and engine boundaries are also considered as fixed supports, ignoring the boundary effect of the local stiffness of the relevant structure. Therefore, the pipeline products designed by the traditional method are conservative, with large design margins and heavy weight. At the same time, the calculated loads on the structure and engine are also large, and the relevant structural design is also conservative.

[0003] Therefore, there is an urgent need to provide a joint simulation method with appropriate calculation volume and high calculation accuracy. Summary of the invention

[0004] In view of the above technical problems in the related art, the present invention provides a

[0005] The present invention provides a launch vehicle pipeline joint simulation method, comprising the following steps:

[0006] Step 1: Draw the three-dimensional models of the engine system, structural system and piping system;

[0007] Step 2: Jointly simulate the engine system, structural system and piping system, and obtain the stress distribution of the structure under static load conditions;

[0008] Step 3: Calculate the static load conditions of the pipeline, bracket and boundary flange;

[0009] Step 4: Calculate the dynamic load conditions of pipelines, brackets and boundary flanges;

[0010] Step 5: After comprehensive evaluation of static load conditions and dynamic load conditions, the dynamic load is obtained;

[0011] Step 6: Analyze the strength of dynamic load conditions according to dynamic load;

[0012] Step 7: Perform strength assessment based on the stress distribution of the structure under static load conditions and the strength under dynamic load conditions. If the strength meets expectations, end the joint simulation of the corresponding pipelines and related interfaces.

[0013] Furthermore, the method for drawing the three-dimensional models of the engine system, structural system and pipeline system is: drawing the three-dimensional model of the pipeline assembly layout; drawing the three-dimensional model of the section, the pipeline sliding bracket and the thrust bracket; and drawing the engine assembly and local three-dimensional model.

[0014] Furthermore, before the joint simulation of the engine system, the structural system and the piping system is performed, the steps include: assembling the three-dimensional models of the piping system, the structural system and the engine system together; and collecting material properties and load conditions.

[0015] Furthermore, in the process of joint simulation of the engine system, structural system and piping system, the main analysis conditions include: flight steady-state maximum internal pressure condition, flight steady-state minimum internal pressure condition, flight engine maximum swing angle condition, and water hammer condition.

[0016] Furthermore, the joint simulation process of the engine system, structural system and piping system includes: selecting component models according to the objects to be analyzed, retaining all load-bearing components on the main force transmission path in the component model; and reserving a part of the components at the analysis boundary to eliminate the influence of boundary effects.

[0017] Furthermore, the method for calculating the static load conditions of the pipeline, the bracket and the boundary flange is: based on the three-dimensional model of the sliding bracket and the thrust bracket, the three-directional displacements and one main rotation angle of the four corner points at the bottom of each sliding bracket and the thrust bracket, and the three-directional displacements and one main rotation angle of the center of the flange mouth, the static load conditions of the pipeline are calculated.

[0018] Furthermore, the method for calculating the dynamic load conditions of the pipeline, bracket and boundary flange is: according to the flight mechanics environment conditions and the local model of the structure and engine interface, the dynamic load conditions of the pipeline, bracket and boundary flange are calculated.

[0019] Furthermore, the method for comprehensively evaluating the static load conditions and dynamic load conditions is: comprehensively evaluating the static load conditions and dynamic load conditions of the pipeline; comprehensively evaluating the static load conditions and dynamic load conditions of the sliding bracket and the thrust bracket; and comprehensively evaluating the static load conditions and dynamic load conditions of the structure and engine-related interface flanges.

[0020] Furthermore, the dynamic load condition strength analysis based on the dynamic load at least includes: performing a dynamic load condition strength analysis on the bracket and flange of the tank shell structure; and performing a dynamic load condition strength analysis on the engine related interface flange.

[0021] Furthermore, the strength evaluation is performed based on the stress distribution of the structure under static load conditions and the strength under dynamic load conditions. If the evaluation result fails, the method returns to the first step to improve the three-dimensional model and perform analysis and calculation again.

[0022] Embodiments of the present invention

[0023] Those skilled in the art will recognize additional features and advantages upon reading the detailed description and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0025] Figure 1 It is a flow chart of the launch vehicle pipeline joint simulation method according to the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific embodiments. Spatial relationship terms such as "below", "below", "under...", "low", "above", "on...", "high", etc. are used to facilitate the description to explain the positioning of an element relative to a second element, indicating that these terms are intended to cover different orientations of the device in addition to orientations different from those shown in the figures. In addition, for example, "an element is above / below another element" can mean that the two elements are in direct contact, or it can mean that there are other elements between the two elements. In addition, terms such as "first", "second", etc. are also used to describe various elements, regions, parts, etc., and should not be regarded as limitations. Similar terms represent similar elements throughout the description.

[0027] See also Figure 1 In order to ensure the mechanical matching between systems and reduce the flight risk caused by the mismatch between systems, the present invention provides a launch vehicle pipeline joint simulation method. It at least includes the following steps:

[0028] S100, drawing a three-dimensional model of the engine system, the structural system and the piping system.

[0029] S200: Jointly simulate the engine system, structural system and piping system, and obtain the stress distribution of the structure under static load conditions.

[0030] S300. Calculate the static load conditions of pipelines, brackets and boundary flanges.

[0031] S400. Calculate the dynamic load conditions of pipelines, brackets and boundary flanges.

[0032] S500. After comprehensive evaluation of static load conditions and dynamic load conditions, the dynamic load is obtained.

[0033] S600. Analyze the strength of dynamic load conditions according to the dynamic load.

[0034] S700, perform strength assessment based on the stress distribution of the structure under static load conditions and the strength under dynamic load conditions. If the strength meets expectations, end the joint simulation of the corresponding pipelines and related interfaces.

[0035] The launch vehicle pipeline joint simulation method of the present invention obtains the real mechanical load of the mechanical interface according to the real product and boundary conditions, and obtains the load of the interface under the real boundary conditions by means of joint simulation. The joint simulation calculation results are used to confirm whether the mechanical performance of the mechanical interface has sufficient safety margin to ensure the coordination of the interface load.

[0036] The launch vehicle pipeline joint simulation method of the present invention performs joint simulation on an engine system, a structural system and a pipeline system, and the simulation software used includes ABAQUS and ANSYS workbench.

[0037] Furthermore, the method of drawing the three-dimensional models of the engine system, the structural system and the pipeline system in S100 is: drawing the three-dimensional model of the pipeline assembly layout, drawing the three-dimensional model of the section, the three-dimensional model of the pipeline sliding bracket and the thrust bracket, and drawing the engine assembly and local three-dimensional model.

[0038] Furthermore, before the joint simulation of the engine system, the structural system and the piping system is performed, the three-dimensional models of the piping system, the structural system and the engine system are assembled together, and material properties and load conditions are collected to facilitate the joint simulation of the engine system, the structural system and the piping system.

[0039] Among them, material properties and load conditions are important input conditions for joint simulation. Specifically, the load input for joint analysis mainly includes the following categories:

[0040] Section load at the structural boundary; temperature of the structural system, piping system and engine system under various working conditions; internal pressure of the structural system, piping system and engine system under various working conditions; thrust of the main engine and the swimming engine of the engine system; swing angle of the main engine and the swimming engine of the engine system; thrust of the servo push rod; water hammer pressure of the engine system and piping system under water hammer working condition.

[0041] Furthermore, in the process of joint simulation of the engine system, structural system and piping system, the main analysis conditions include: flight steady state maximum internal pressure condition, flight steady state minimum internal pressure condition, flight engine maximum swing angle condition, water hammer condition. Envelope values ​​should be selected for each condition to analyze the 6-DOF displacement and 6-DOF force and moment at the joint and sliding bracket of the piping system, structural system and engine system.

[0042] Furthermore, the joint simulation process of the engine system, the structural system and the piping system includes: selecting a component model according to the object to be analyzed, retaining all load-bearing components on the main force transmission path in the component model, and reserving a part of the components at the analysis boundary to eliminate the influence of the boundary effect.

[0043] Specifically, the component models that need to be included should be selected according to the object to be analyzed. The analysis model that should be retained should include all the load-bearing components on the main force transmission path where the object to be analyzed is located, and a part of the components should be retained at the analysis boundary to eliminate the influence of the boundary effect. The joint analysis model processing should minimize the number of overall grids. The tank barrel section, front and rear bottom and short shell of the structural system use shell elements, and the number of structural units using solid elements for the rest should be as small as possible. The pipelines of the pipeline system use shell elements, and the flanges are simplified as much as possible without affecting the overall stiffness. The frame of the engine system is recommended to use beam elements first, followed by shell elements. It is recommended to use stiffness equivalent models for other components with complex structures and large stiffness. The compensator of the pipeline system uses a 6-degree-of-freedom bushing unit, and nonlinear stiffness should be given in the axial direction. Under the premise of not affecting the overall stiffness of the structure, it is recommended to use common nodes, binding, MPC and other constraints between the components. It is recommended that the fixed support boundary condition be applied to the structural system, and the application position is to add an additional section of the structural system on the basis of the analysis model to eliminate the local influence of the boundary on the joint simulation model.

[0044] Furthermore, the method of S300 for calculating the static load conditions of pipelines, brackets and boundary flanges is as follows: based on the three-dimensional models of the sliding brackets and thrust brackets, combined with the three-directional displacements and one main rotation angle of the four corner points at the bottom of each sliding bracket and thrust bracket, and the three-directional displacements and one main rotation angle of the center of the flange mouth, the static load conditions of the pipeline are calculated.

[0045] Specifically, after applying displacement and rotation to the pipeline, bracket and boundary flange, pressure load and temperature environment are applied to the pipeline according to the working conditions to obtain the stress level of the products on the pipeline, bracket and boundary flange. Under the comprehensive conditions of various loads, the stress level of each product is kept from yielding as much as possible, and local small-scale yield is allowed.

[0046] Furthermore, the method for calculating the dynamic load conditions of the pipeline, the bracket and the boundary flange in S400 is: the dynamic load conditions of the pipeline, the bracket and the boundary flange are calculated according to the flight mechanics environment conditions and the local model of the structure and the engine interface.

[0047] Specifically, when the product is subjected to the above-mentioned static load conditions, dynamic loads are applied according to mechanical environmental conditions. Low-frequency sinusoidal vibration analysis is first performed to record the maximum vibration stress at each dangerous position of the structure. Random vibration analysis is then performed to record the maximum vibration stress at each dangerous position of the structure, and finally fatigue analysis is performed. Regarding vibration fatigue analysis, if the linear superposition of the vibration stress at the dangerous point and the static stress does not enter yield, high-cycle fatigue assessment is used, otherwise low-cycle fatigue is used, and all the above damage coefficients are accumulated, requiring the damage coefficient not to exceed 0.2.

[0048] Further, S500 obtains the dynamic load after comprehensively evaluating the static load condition and the dynamic load condition, wherein the method for comprehensively evaluating the static load condition and the dynamic load condition is: comprehensively evaluating the static load condition and the dynamic load condition of the pipeline. Comprehensively evaluating the static load condition and the dynamic load condition of the sliding bracket and the thrust bracket. And comprehensively evaluating the static load condition and the dynamic load condition of the structure and the engine-related interface flange. After the evaluation, the dynamic load of the pipeline, the dynamic load of the sliding bracket and the thrust bracket, and the dynamic load of the structure and the engine-related interface flange are obtained.

[0049] Furthermore, S600 analyzing the dynamic load condition strength according to the dynamic load at least includes: performing a dynamic load condition strength analysis on the bracket and flange of the tank shell structure, and performing a dynamic load condition strength analysis on the engine related interface flange.

[0050] The launch vehicle pipeline joint simulation method of the present invention can perform dynamic load strength analysis of the bracket and flange of the tank shell structure according to the dynamic load of the pipeline bracket and the related flange, and superimpose the structural stress distribution of the static load (flight condition) to evaluate the strength of the structure. The engine professional performs dynamic load strength analysis of the engine-related interface flanges, and superimposes the structural stress distribution of the static load (flight condition) to evaluate the strength of the engine interface flange. If the above evaluation is passed, the joint simulation of the pipeline and related interfaces is closed. If the evaluation result fails, it is necessary to return to the first step to improve the model and perform analysis and calculation again.

[0051] The launch vehicle pipeline joint simulation method of the present invention gives full play to the professional advantages of structural strength calculation, pipeline simulation calculation and engine simulation calculation, has a moderate calculation scale, greatly improves the calculation accuracy of pipelines and related interface products, reduces the influence of boundary effects, reduces the weight of products, and contributes to improving the carrying capacity of rockets.

[0052] The above embodiments can be combined with each other and have corresponding technical effects.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A launch vehicle pipeline joint simulation method, characterized in that: At least the following steps are included: Draw three-dimensional models of engine system, structural system and piping system; Conduct joint simulation of the engine system, structural system and piping system, and obtain the stress distribution of the structure under static load conditions; Calculate static load cases for piping, brackets and boundary flanges; Calculate dynamic load cases for piping, brackets and boundary flanges; The dynamic load is obtained after comprehensive evaluation of static load conditions and dynamic load conditions; Analyze the strength of dynamic load conditions according to dynamic load; Perform strength assessment based on the stress distribution of the structure under static load conditions and the strength under dynamic load conditions. If the strength meets expectations, end the joint simulation of the corresponding pipelines and related interfaces. The method for drawing the three-dimensional models of the engine system, the structural system and the pipeline system comprises: drawing a three-dimensional model of the pipeline assembly layout; Draw the 3D model of the section, pipeline sliding bracket and thrust bracket; as well as Draw engine assembly and local 3D models; The joint simulation process of the engine system, structural system and piping system includes: Select a component model according to the object to be analyzed, and retain all load-bearing components on the main force transmission path in the component model; A portion of components is reserved at the analysis boundary to eliminate the influence of boundary effects.

2. The launch vehicle pipeline joint simulation method according to claim 1, characterized in that: Before the joint simulation of the engine system, the structural system and the pipeline system is performed, the method includes: assembling the three-dimensional models of the pipeline system, the structural system and the engine system together; Collect material properties and load cases.

3. The launch vehicle pipeline joint simulation method according to claim 2 is characterized in that: During the joint simulation of the engine system, structural system and piping system, the main analysis conditions include: maximum internal pressure condition in steady flight, minimum internal pressure condition in steady flight, maximum engine swing angle condition in flight, and water hammer condition.

4. The launch vehicle pipeline joint simulation method according to claim 1, characterized in that: The method for calculating the static load conditions of the pipeline, bracket and boundary flange is: The static load condition calculation of the pipeline is carried out based on the three-dimensional model of the sliding bracket and the thrust bracket, the three-directional displacements and one main rotation angle of the four corner points at the bottom of each sliding bracket and the thrust bracket, and the three-directional displacements and one main rotation angle of the flange center.

5. The launch vehicle pipeline joint simulation method according to claim 1, characterized in that: The method for calculating the dynamic load conditions of the pipeline, bracket and boundary flange is: Dynamic load cases for pipes, brackets and boundary flanges are calculated based on flight dynamics environmental conditions and local models of the structure and engine interface.

6. The launch vehicle pipeline joint simulation method according to claim 1, characterized in that: The method for comprehensive evaluation of static and dynamic load conditions is: Comprehensively evaluate the static and dynamic load conditions of the pipeline; Comprehensive evaluation of static and dynamic load conditions of sliding brackets and thrust brackets; as well as Comprehensive evaluation of static and dynamic load conditions is performed on the structure and engine-related interface flanges.

7. The launch vehicle pipeline joint simulation method according to claim 1, characterized in that: Analyzing the strength of dynamic load conditions according to the dynamic load at least includes: Conduct dynamic load strength analysis of the brackets and flanges of the tank shell structure; and Conduct dynamic load strength analysis of engine-related interface flanges.

8. The launch vehicle pipeline joint simulation method according to claim 1, characterized in that: The strength assessment is performed based on the stress distribution of the structure under static load conditions and the strength under dynamic load conditions. If the assessment result fails, the process returns to the first step to improve the three-dimensional model and perform analysis and calculation again.

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