A method for synthetically determining distributed loads of a complex transmission cabin section of a bundled rocket

Abstract

A kind of comprehensive determination method of complex force transmission cabin section distributed load of binding rocket, comprising: extracting the distributed load of all sub-loads, and converting to the load borne by core stage connecting cabin section in arrow body coordinate system;Based on the load borne by core stage connecting cabin section in arrow body coordinate system, the analytical model of the distributed load of all sub-loads is parameter fitted, and the analytical expression containing transverse main direction angle variable is obtained;Based on the analytical expression of transverse main direction angle variable, the longitudinal static load and the distributed load of other arbitrary direction sub-loads are combined to realize arbitrary direction load distribution coverage, and the combination result can obtain the comprehensive distributed binding load by inverse transformation.The method of the application makes the distributed binding load analytical, and the feasibility of combining each sub-load in any transverse main direction can be realized.

Description

Technical Field

[0001] This invention relates to a comprehensive method for determining distributed loads in complex force transmission modules of a rocket, and relates to the field of load design in aerospace engineering. Background Technology

[0002] In launch vehicle payload design, different calculation methods are first used to obtain different types of sub-loads based on the characteristics of different excitation sources. These sub-loads include longitudinal static loads, lateral static loads, sloshing loads, and lateral dynamic loads (fluttering loads, gust loads). Then, the sub-loads are combined to obtain the overall payload. Load integration design is relatively simple for handling scalar values. For example, the load on the main structural section of the rocket body includes shear force, bending moment, and axial compression. The overall payload can be obtained by taking the maximum value of each sub-load and performing probability calculations. Distributed payloads, however, are represented as vectors composed of multiple scalars. The severity of the load is also related to spatial distribution, and there is no clear or simple algorithm to obtain the overall payload. Taking a launch vehicle with four boosters as an example, the binding load borne by the core stage binding connection section is represented as a group of distributed binding loads at the four booster binding positions. This includes the axial force of the 12 connecting rods of the auxiliary binding mechanism, the constraint forces of 3 translational degrees of freedom in each main binding mechanism, and a total of 24 components of distributed payload vectors for the front and rear bindings. The severity assessment of loads requires consideration of multiple factors, including structural symmetry, load symmetry, load component distribution, and structural failure modes; individual load components cannot be treated separately. Distributed loads also present the problem of correlation with the direction of external excitation, meaning that the distributed loads in each sub-item are related to the direction of external excitation. For example, lateral static load calculations, whether performed separately for pitch and yaw channels or combined calculations, are all related to the direction of external excitation, while structural bearing capacity must consider all possibilities in the lateral direction; a comprehensive load cannot be obtained by simply superimposing the individual sub-items. Summary of the Invention

[0003] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and solve the problem of determining the distributed bundled load of complex force transmission modules in a bundled rocket.

[0004] The objective of this invention is achieved through the following technical solutions:

[0005] A comprehensive method for determining distributed loads in a complex force transmission section of a rocket includes:

[0006] Extract the distributed loads of all sub-loads and convert them to the loads borne by the core stage connecting section in the rocket body coordinate system;

[0007] Based on the load borne by the core stage connecting section in the rocket body coordinate system, the analytical model of the distributed load of all sub-loads is parametrically fitted to obtain an analytical expression that includes the lateral principal direction angle variable.

[0008] Based on the analytical expression that includes the lateral principal direction angle variable, the distributed loads of the longitudinal static load and the sub-item loads in other arbitrary directions are combined to achieve load distribution coverage in any direction. The combined result can be obtained by inverse transformation to obtain the integrated distributed bundled load.

[0009] In one embodiment of the present invention, the analytical model for lateral static load includes:

[0010] Analytical model of equivalent load for auxiliary binding:

[0011]

[0012] Main bundle equivalent load analytical model:

[0013]

[0014] In the formula:

[0015] b — Subscript b, the serial number of the binding organization, b = 1, 2, 3, 4, ...;

[0016] α b —The quadrant angle of the location of the binding mechanism in serial number b, with a value range of 0 to 360°;

[0017] α—The principal direction angle of the lateral load, ranging from 0 to 360°;

[0018] {F fk,b}——Auxiliary binding equivalent load vector;

[0019] {F zk,b}——Main binding equivalent load vector, b is the binding mechanism number;

[0020] R x,b —The moment component of the equivalent binding load in the X-axis direction in the rocket body coordinate system;

[0021] F x,b —Equivalent binding load force component in the X-axis direction in the rocket body coordinate system;

[0022] F y,b —The force component of the equivalent binding load in the Y-axis direction in the rocket body coordinate system;

[0023] F z,b —Equivalent binding load force component in the Z-axis direction in the rocket body coordinate system;

[0024] A1, B1, C1, D1, E1, A2, B2, C2, D2, and E2 are all constant parameters.

[0025] In one embodiment of the present invention, the equivalent binding load analytical model of the lateral dynamic load includes:

[0026] Analytical model of equivalent load for auxiliary binding:

[0027]

[0028] Main bundle equivalent load analytical model:

[0029]

[0030] In the formula:

[0031] b — Subscript b, the serial number of the binding organization, b = 1, 2, 3, 4, ...;

[0032] α b —The quadrant angle of the location of the binding mechanism in serial number b, with a value range of 0 to 360°;

[0033] α—The principal direction angle of the lateral load, ranging from 0 to 360°;

[0034] {F fk,b}——Auxiliary binding equivalent load vector;

[0035] {F zk,b}——Main bundle equivalent load vector;

[0036] R x,b —Equivalent binding load torque component in the X-axis direction of the rocket body coordinate system;

[0037] F x,b —Force component in the X-axis direction under the equivalent binding load in the rocket body coordinate system;

[0038] F y,b —Force component in the Y-axis direction under the equivalent binding load in the rocket body coordinate system;

[0039] F z,b —Force component in the Z-axis direction under the equivalent binding load in the rocket body coordinate system;

[0040] [T z,b — Coordinate transformation matrix, transforming from the booster coordinate system to the rocket body coordinate system;

[0041] [T fk,b — Equivalent load transformation matrix, which is related to the distribution position of the three links of each auxiliary binding mechanism in the booster coordinate system;

[0042] K1, K2 — First-order and second-order modal generalized stiffness based on mass normalization;

[0043] —Auxiliary bundled load vectors in first- and second-order modal generalized loads based on mass normalization. Represents first-order and second-order modes;

[0044] —The main bound load vector in the first- and second-order modal generalized loads based on mass normalization;

[0045] A3, A4 — Constant parameters.

[0046] In one embodiment of the present invention, the distributed bundled load includes a main bundled load and an auxiliary bundled load.

[0047] In one embodiment of the present invention, the sub-loads include longitudinal static load, lateral static load, sway load, flutter load, and gust load.

[0048] In one embodiment of the present invention, the analytical expression for the comprehensive load of the distributed equivalent bundled load is:

[0049]

[0050] In the formula:

[0051] j——subscript j, the number of the sub-loads other than the longitudinal static load, j=1~N;

[0052] α j —The transverse principal direction of the j-th sub-item load, with a value range of 0 to 360°;

[0053] {F} — Distributed equivalent bundled load vector of the comprehensive load;

[0054] {F0}——Distributed equivalent bundled load vector of longitudinal static load;

[0055] {F j (α j )}——The j-th component load with respect to variable α j Analytical model.

[0056] In one embodiment of the present invention, the inverse transformation formula for the auxiliary binding load is:

[0057]

[0058] In the formula: [T z ] -1 —Coordinate system inverse transformation matrix, transforming from the rocket body coordinate system to the booster coordinate system;

[0059] [T fk ] -1 — Equivalent load inverse transformation matrix;

[0060] R x —Auxiliary binding equivalent load, torque component in the X-axis direction in the rocket body coordinate system;

[0061] F y —Auxiliary binding equivalent load, force component in the Y-axis direction in the rocket body coordinate system;

[0062] F z —Auxiliary binding equivalent load, force component in the Z-axis direction in the rocket body coordinate system;

[0063] N1, N2, N3 — Auxiliary binding loads, the internal force loads of the three connecting rods numbered 1, 2, and 3 in sequence. The values ​​are positive when the rods are under tension and negative when they are under compression.

[0064] In one embodiment of the present invention, the inverse transformation formula for the main binding load is:

[0065]

[0066] In the formula: [T z ] -1 —Coordinate system inverse transformation matrix, transforming from the rocket body coordinate system to the booster coordinate system;

[0067] F x —Equivalent load of main binding, force component in the X-axis direction in the rocket body coordinate system;

[0068] F y —Equivalent load of main binding, force component in the Y-axis direction in the rocket body coordinate system;

[0069] F z —Equivalent load of main binding, force component in the Z-axis direction in the rocket body coordinate system;

[0070] N4—Main binding load, force component in the Xz axis direction under the booster coordinate system;

[0071] N5—Main binding load, force component in the Yz axis direction under the booster coordinate system;

[0072] N6—Main binding load, force component in the Zz axis direction under the booster coordinate system.

[0073] In one embodiment of the present invention, a binding mechanism is used to connect the booster and the core stage rocket body so that the two do not move relative to each other and to realize the transmission of the interaction force between the two during rocket flight.

[0074] In one embodiment of the present invention, the main binding mechanism is a ball joint structure that constrains three translational degrees of freedom and transmits three translational force loads; the auxiliary binding mechanism is a three-bar linkage, in which each bar only bears tensile and compressive loads along the axial direction of the bar.

[0075] A comprehensive method for determining distributed loads in a complex force transmission section of a rocket includes:

[0076] S1. Extract the distributed bundled loads of each sub-item load;

[0077] S2. The distributed bundled loads of each sub-item load are equivalently converted into equivalent bundled loads acting on the core stage connecting section in the rocket body coordinate system, thus obtaining the distributed equivalent bundled loads of each sub-item load.

[0078] S3. Establish analytical expressions for distributed equivalent bundled loads. Classify loads according to lateral static loads, lateral dynamic loads, and auxiliary and main bundles. Select analytical models for different distributed equivalent bundled loads. Use the distributed equivalent bundled load data obtained in S2 to perform parameter fitting, obtaining analytical expressions for the distributed bundled equivalent loads of each component load. The analytical expressions for distributed bundled equivalent loads include the lateral principal direction angle α. j variable;

[0079] S4. Based on the analytical expression of the distributed bundled equivalent load of the sub-items load described in S3, the comprehensive load analytical expression of the distributed equivalent bundled load is obtained by combining the longitudinal static load with the transverse sub-items load of any transverse principal direction angle.

[0080] S5. Based on the analytical expression of the comprehensive load of the distributed equivalent bundled load described in S4, the comprehensive distributed bundled load is obtained through the relative load equivalent inverse transformation, that is, the comprehensive load of the distributed bundled load.

[0081] Compared with the prior art, the present invention has the following advantages:

[0082] (1) The method for determining the distributed bundled load of complex force transmission compartment of bundled rocket proposed in this invention proposes an analytical model of the lateral load with respect to any lateral main direction, so as to make the distributed bundled load analytical.

[0083] (2) This invention obtains parameters through fitting and realizes the analytical expression of each sub-item load for any main transverse direction;

[0084] (3) The comprehensive load analytical expression of the distributed equivalent bundled load of the present invention contains different lateral main directions of each sub-item load, which realizes the feasibility of combining each sub-item load in any lateral main direction.

[0085] (4) The present invention can ensure the sufficiency of the strength verification of the binding connection section through an unlimited number of combinations. Attached Figure Description

[0086] Figure 1 This is a flowchart of the steps of the method of the present invention;

[0087] Figure 2 Schematic diagram of distributed bundled loads;

[0088] Figure 3Schematic diagram of auxiliary binding load components;

[0089] Figure 4 Schematic diagram of the main binding load components. Detailed Implementation

[0090] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0091] The coordinate system in this invention is defined as follows:

[0092] Rocket body coordinate system O-XYZ: The circumferential references of the rocket are represented by I, II, III, and IV. The origin of the coordinate system O is the center of mass of the entire rocket. The X-axis is along the longitudinal axis of the rocket and points towards the nose. The Y-axis is in the longitudinal symmetry plane of the rocket, perpendicular to the OX-axis, and points from I to the III reference, which is the III reference line of the rocket body. The Z-axis, together with the X and Y axes, forms a right-handed coordinate system.

[0093] The booster coordinate system Oz-XzYzZz: the subscript z is the abbreviation of the Chinese pinyin for booster, the origin of the coordinate system Oz is the center of mass of the booster, the Xz axis coincides with the longitudinal axis of the booster and points towards the head as positive; the Yz axis is in a plane perpendicular to the longitudinal axis of the booster and points from the center of the booster to the center of the core stage; the Zz axis is determined according to the right-hand rule.

[0094] The compartments and mechanisms in this invention are defined as follows:

[0095] Complex force transmission section: refers to the binding mechanism (including main binding and auxiliary binding) of the rocket and the rocket body structural section that connects the binding mechanism.

[0096] The binding mechanism is used to connect the boosters and the core stage of the rocket, preventing relative motion between them and transmitting the interaction forces between them during flight. Binding rockets typically contain two or more boosters, each connected to the core stage, requiring at least one main binding mechanism and one auxiliary binding mechanism. The main binding mechanism is a ball-joint structure, constraining three translational degrees of freedom and transmitting three translational force loads. The auxiliary binding mechanism is a three-bar linkage, with each bar only bearing tensile and compressive loads along its axial direction.

[0097] The load in this invention is defined as follows:

[0098] Binding load: refers to the internal force load borne by the binding mechanism; according to the type of binding mechanism (main binding mechanism, auxiliary binding mechanism), it is divided into main binding load and auxiliary binding load, such as... Figure 3 and Figure 4 As shown.

[0099] Equivalent binding load: refers to the equivalent force and moment exerted by the binding mechanism on the core stage structural section in the rocket body coordinate system, including the main binding equivalent load and the auxiliary binding equivalent load.

[0100] Auxiliary binding load: refers to the internal force load borne by the auxiliary binding mechanism. Each set of auxiliary binding mechanism contains 3 load components N1, N2, and N3, which refer to the internal force load of the three connecting rods numbered 1, 2, and 3 respectively. The value is positive when the rod is under tension and negative when it is under compression.

[0101] Main binding load: refers to the internal force load borne by the main binding mechanism. Each main binding mechanism contains three load components N4, N5, and N6, which are the Xz-axis, Yz-axis, and Zz-axis components in the booster coordinate system, respectively, with the point of application at the center of the ball joint. The direction of each component indicates the direction of the force exerted by the booster on the core stage; a negative value indicates the opposite direction of the force.

[0102] Auxiliary binding equivalent load: refers to the equivalent force and torque exerted by the auxiliary binding mechanism on the core stage in the rocket body coordinate system. Each auxiliary binding mechanism contains three components R. x F y F z These represent the torque along the X-axis and the force along the Y and Z axes in the rocket's coordinate system, respectively. The point of application is the center point of the nearest position on the outer boundary of the line connecting the center of the core stage and the center of the booster, within the transverse plane of the auxiliary binding mechanism.

[0103] Main binding equivalent load: refers to the force exerted by the main binding mechanism on the core stage in the rocket body coordinate system. Each main binding mechanism contains three components F. x F y F z These are the forces acting along the X, Y, and Z axes of the rocket's coordinate system, respectively.

[0104] Distributed bundled loads: In a bundled rocket that bundles multiple boosters, this refers to the collection of bundled loads from all the bundling mechanisms distributed across different locations in space. For example... Figure 2

[0105] Distributed equivalent bundled load: refers to the set of equivalent bundled loads of all bundled mechanisms distributed in different spatial locations in a bundled rocket that bundles multiple boosters.

[0106] Sub-loads refer to the different loads exerted on the rocket's structure during flight by various factors (such as engine thrust, lateral aerodynamic forces, control forces, fluid sloshing, gusts, and pulses). These loads include at least longitudinal static loads, lateral static loads, sloshing loads, gust loads, and flutter loads. Sloshing loads, gust loads, and flutter loads can also be classified as lateral dynamic loads. Lateral static loads and lateral dynamic loads can also be classified as lateral loads.

[0107] Combined load: refers to the load that the rocket body structure bears when it is subjected to multiple factors simultaneously during flight.

[0108] A comprehensive method for determining distributed loads in complex force transmission sections of a rocket, such as... Figure 1 As shown, the specific implementation process is as follows:

[0109] S1. Extract the sub-item loads. Extract the distributed bundled loads (including main bundled loads and auxiliary bundled loads) of the complex force transmission section from the calculation results of the sub-item loads of the bundled rocket. The sub-item loads include longitudinal static loads, lateral static loads, sway loads, flutter loads, and gust loads.

[0110] S2. Equivalent transformation of binding loads: the main binding load is transformed into the main binding equivalent load in the rocket body coordinate system; the auxiliary binding load is transformed into the auxiliary binding equivalent load in the rocket body coordinate system.

[0111] Equivalent conversion formula for auxiliary binding equivalent load:

[0112]

[0113] In the formula:

[0114] {F fk}——Auxiliary binding equivalent load vector;

[0115] R x —Equivalent binding load, torque component in the X-axis direction in the rocket body coordinate system;

[0116] F y —Equivalent binding load, force component in the Y-axis direction in the rocket body coordinate system;

[0117] F z —Equivalent binding load, force component in the Z-axis direction in the rocket body coordinate system;

[0118] [T z — Coordinate transformation matrix, transforming from the booster coordinate system to the rocket body coordinate system;

[0119] [T fk — Equivalent load transformation matrix, which is related to the distribution position of the three links of each auxiliary binding mechanism in the booster coordinate system;

[0120] N1, N2, N3 — Auxiliary binding loads, the internal force loads of the three connecting rods numbered 1, 2, and 3 in sequence. The values ​​are positive when the rods are under tension and negative when they are under compression.

[0121] Equivalent conversion formula for main bundle equivalent load:

[0122]

[0123] In the formula:

[0124] {F zk}——Main bundle equivalent load vector;

[0125] F x —Equivalent binding load, force component in the X-axis direction in the rocket body coordinate system;

[0126] F y —Equivalent binding load, force component in the Y-axis direction in the rocket body coordinate system;

[0127] F z —Equivalent binding load, force component in the Z-axis direction in the rocket body coordinate system;

[0128] [T z — Coordinate transformation matrix, transforming from the booster coordinate system to the rocket body coordinate system;

[0129] N4—Main binding load, force component in the Xz axis direction under the booster coordinate system;

[0130] N5—Main binding load, force component in the Yz axis direction under the booster coordinate system;

[0131] N6—Main binding load, force component in the Zz axis direction under the booster coordinate system.

[0132] S3 selects an analytical model to fit the distributed equivalent bundled loads of each load.

[0133] In each load component, the longitudinal static load has a fixed direction and magnitude, requiring no special treatment. However, the lateral load needs to consider the possibility of arbitrary directions within the lateral plane. By fitting parameters to the analytical model of the distributed equivalent bundled load, the bundled loads with respect to their spatial distribution are analytically represented, enabling rotation in any direction within the lateral plane. Different analytical models are selected for the lateral loads based on their classification as lateral static loads and lateral dynamic loads.

[0134] (1) Analytical model of equivalent binding load for lateral static load

[0135] Analytical model of equivalent load for auxiliary binding:

[0136]

[0137] Main bundle equivalent load analytical model:

[0138]

[0139] In the formula:

[0140] b — Subscript b, the serial number of the binding organization, b = 1, 2, 3, 4, ...;

[0141] α b —The quadrant angle of the location of the binding mechanism in serial number b, with a value range of 0 to 360°;

[0142] α—The principal direction angle of the lateral load, ranging from 0 to 360°;

[0143] {F fk,b}——Auxiliary binding equivalent load vector, where b is the binding mechanism number;

[0144] {F zk,b}——Main binding equivalent load vector, b is the binding mechanism number;

[0145] R x,b —Equivalent binding load, the moment component in the X-axis direction in the rocket body coordinate system, where b is the binding mechanism number;

[0146] F x,b —Equivalent binding load, force component in the X-axis direction in the rocket body coordinate system, where b is the binding mechanism number;

[0147] F y,b —Equivalent binding load, force component in the Y-axis direction in the rocket body coordinate system, where b is the binding mechanism number;

[0148] F z,b —Equivalent binding load, force component in the Z-axis direction in the rocket body coordinate system, where b is the binding mechanism number;

[0149] A1,B1,C1,D1,E1,A2,B2,C2,D2,E2 — Constant parameters.

[0150] (2) Analytical model of equivalent binding load for lateral dynamic load

[0151] Analytical model of equivalent load for auxiliary binding:

[0152]

[0153] Main bundle equivalent load analytical model:

[0154]

[0155] In the formula:

[0156] b — Subscript b, the serial number of the binding organization, b = 1, 2, 3, 4, ...;

[0157] α b —The quadrant angle of the location of the binding mechanism in serial number b, with a value range of 0 to 360°;

[0158] α—The principal direction angle of the lateral load, ranging from 0 to 360°;

[0159] {F fk,b}——Auxiliary binding equivalent load vector, where b is the binding mechanism number;

[0160] {F zk,b}——Main binding equivalent load vector, b is the binding mechanism number;

[0161] R x,b —Equivalent binding load, torque component in the X-axis direction in the rocket body coordinate system, where b is the binding mechanism number;

[0162] F x,b —Equivalent binding load, force component in the X-axis direction in the rocket body coordinate system, where b is the binding mechanism number;

[0163] F y,b —Equivalent binding load, force component in the Y-axis direction in the rocket body coordinate system, where b is the binding mechanism number;

[0164] F z,b —Equivalent binding load, force component in the Z-axis direction in the rocket body coordinate system, where b is the binding mechanism number;

[0165] [T z,b — Coordinate system transformation matrix, transforming from the booster coordinate system to the rocket body coordinate system, where b is the serial number of the binding mechanism;

[0166] [T fk,b — Equivalent load transformation matrix, which is related to the distribution position of the three-link linkage of each auxiliary binding mechanism in the booster coordinate system, where b is the binding mechanism number;

[0167] K1, K2 — First-order and second-order modal generalized stiffness based on mass normalization;

[0168] —Based on the auxiliary binding load vector in the first and second modal generalized loads with mass normalization, where b is the binding mechanism number. Represents first-order and second-order modes;

[0169] —Based on the main binding load vector in the first and second-order modal generalized loads with mass normalization, where b is the binding mechanism number. It represents the first-order and second-order modes.

[0170] A3, A4 — Constant parameters;

[0171] Based on the distributed equivalent bundled load data of each sub-load obtained in step S2 above, the constant parameters A, B, C, D, and E in each analytical model are obtained by fitting the model parameters, thus obtaining the analytical expression of the distributed equivalent bundled load of each sub-load. The distributed equivalent bundled load in any transverse load principal direction can be calculated by rotating the transverse load principal direction angle α.

[0172] S4 Distributed Equivalent Bundled Load Synthesis. By combining the analytical models of the distributed equivalent bundled loads for each component load, the comprehensive analytical expression of the distributed equivalent bundled load is obtained:

[0173]

[0174] In the formula:

[0175] j——subscript j, the number of the sub-loads other than the longitudinal static load, j=1~N;

[0176] α j —The transverse principal direction of the j-th sub-item load, with a value range of 0 to 360°;

[0177] {F} — Distributed equivalent bundled load vector of the comprehensive load;

[0178] {F0}——Distributed equivalent bundled load vector of longitudinal static load;

[0179] {F j (α j )}——The j-th component load with respect to variable α j The analytical model is obtained by taking the parameters in step S3 above.

[0180] The analytical expression for the comprehensive load is about the principal directions α of each component load. j The analytical expression can, in principle, combine the individual loads in any principal direction.

[0181] S5 obtains the combined load of the distributed bundled loads through inverse transformation.

[0182] Formula for calculating the inverse transformation of auxiliary binding load:

[0183]

[0184] In the formula: [T z ] -1 —Coordinate system inverse transformation matrix, transforming from the rocket body coordinate system to the booster coordinate system;

[0185] [T fk ] -1 — Equivalent load inverse transformation matrix.

[0186] R x —Auxiliary binding equivalent load, torque component in the X-axis direction in the rocket body coordinate system;

[0187] F y —Auxiliary binding equivalent load, force component in the Y-axis direction in the rocket body coordinate system;

[0188] F z—Auxiliary binding equivalent load, force component in the Z-axis direction in the rocket body coordinate system;

[0189] N1, N2, N3 — Auxiliary binding loads, the internal force loads of the three connecting rods numbered 1, 2, and 3 in sequence. The values ​​are positive when the rods are under tension and negative when they are under compression.

[0190] Formula for calculating the inverse transformation of the main binding load:

[0191]

[0192] In the formula: [T z ] -1 — Coordinate system inverse transformation matrix, transforming from the rocket body coordinate system to the booster coordinate system.

[0193] F x —Equivalent load of main binding, force component in the X-axis direction in the rocket body coordinate system;

[0194] F y —Equivalent load of main binding, force component in the Y-axis direction in the rocket body coordinate system;

[0195] F z —Equivalent load of main binding, force component in the Z-axis direction in the rocket body coordinate system;

[0196] N4—Main binding load, force component in the Xz axis direction under the booster coordinate system;

[0197] N5—Main binding load, force component in the Yz axis direction under the booster coordinate system;

[0198] N6—Main binding load, force component in the Zz axis direction under the booster coordinate system.

[0199] According to the present invention, the analytical expression of the load of the core stage main binding section for any combination of the loads in any direction is obtained. Taking the main directions of each component in the same or opposite direction can usually obtain the most severe working conditions.

[0200] The present invention proposes a comprehensive method for distributed bundled loads of complex force transmission compartments in bundled rockets. By fitting the parameters of the analytical model with each component load, the analytical expression of the distributed load in any main direction is obtained. This enables the combination of longitudinal static load and each component lateral load in any direction, and by selecting a series of directional combinations, the comprehensive load of the distributed loads of the complex force transmission compartments is obtained.

[0201] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0202] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A comprehensive method for determining distributed loads in a complex force transmission section of a rocket, characterized in that, include: Extract the distributed loads of all sub-loads and convert them to the loads borne by the core stage connecting section in the rocket body coordinate system; Based on the load borne by the core stage connecting section in the rocket body coordinate system, the analytical model of the distributed load of all sub-loads is parametrically fitted to obtain an analytical expression that includes the lateral principal direction angle variable. Based on the analytical expression that includes the lateral principal direction angle variable, the distributed load of longitudinal static load and other arbitrary direction component loads is combined to achieve arbitrary direction load distribution coverage. The combined result can be obtained by inverse transformation to obtain the integrated distributed bundled load. The analytical model for lateral static load includes: Analytical model of equivalent load for auxiliary binding: Main bundle equivalent load analytical model: In the formula: —subscript b Bundling organization serial number =1,2,3,4,…; ——Serial Number b The quadrant angle of the location of the binding mechanism, ranging from 0 to 360°; —The principal direction angle of the lateral load, with a value range of 0~360°; —Auxiliary binding equivalent load vector; —Main bundled equivalent load vector, b For the serial number of the bundling organization; —The moment component of the equivalent binding load in the X-axis direction in the rocket body coordinate system; —Equivalent binding load force component in the X-axis direction in the rocket body coordinate system; —The force component of the equivalent binding load in the Y-axis direction in the rocket body coordinate system; —Equivalent binding load force component in the Z-axis direction in the rocket body coordinate system; A 1 ,B 1 ,C 1 ,D 1 ,E 1 , A 2 ,B 2 ,C 2 ,D 2 ,E Both are constant parameters; The equivalent binding load analytical model for lateral dynamic loads includes: Analytical model of equivalent load for auxiliary binding: Main bundle equivalent load analytical model: In the formula: — Coordinate transformation matrix, transforming from the booster coordinate system to the rocket body coordinate system; —The equivalent load transformation matrix is ​​related to the distribution position of the three links of each auxiliary binding mechanism in the booster coordinate system; , — First-order and second-order modal generalized stiffness based on mass normalization; , —Auxiliary bundled load vectors in first- and second-order modal generalized loads based on mass normalization. , Represents first-order and second-order modes; , —The main bound load vector in the first- and second-order modal generalized loads based on mass normalization; A 3 ，A 4 — Constant parameters; , , —Auxiliary binding load; —Main binding load, force component in the Xz axis direction in the boosting coordinate system; —Main binding load, force component in the Yz axis direction in the boosting coordinate system; —Main binding load, force component in the Zz axis direction under the boosting coordinate system.

2. The comprehensive determination method according to claim 1, characterized in that, Distributed bundled loads include primary bundled loads and secondary bundled loads.

3. The comprehensive determination method according to claim 1, characterized in that, The sub-loads include longitudinal static load, lateral static load, sway load, buffeting load, and gust load.

4. The comprehensive determination method according to claim 1, characterized in that, The analytical expression for the combined load of the distributed equivalent bundled load is: In the formula: —subscript j The sub-load numbers other than longitudinal static loads, j= 1~ N ; ——No. The transverse principal direction of the sub-item load, with a value range of 0~360°; —Distributed equivalent bundled load vector of the combined load; —Distributed equivalent bundled load vector of longitudinal static load; ——No. Item loads with respect to variables Analytical model.

5. The comprehensive determination method according to claim 1, characterized in that, The inverse transformation formula for auxiliary binding load is: In the formula: —Coordinate system inverse transformation matrix, transforming from the rocket body coordinate system to the booster coordinate system; — Equivalent load inverse transformation matrix; —Auxiliary binding equivalent load, torque component in the X-axis direction in the rocket body coordinate system; —Auxiliary binding equivalent load, force component in the Y-axis direction in the rocket body coordinate system; —Auxiliary binding equivalent load, force component in the Z-axis direction in the rocket body coordinate system; , , —Auxiliary binding load, the internal force load of the three connecting rods numbered 1, 2, and 3 in sequence. The value is positive when the rod is under tension and negative when it is under compression.

6. The comprehensive determination method according to claim 1, characterized in that, The inverse transformation formula for the main binding load is: In the formula: —Coordinate system inverse transformation matrix, transforming from the rocket body coordinate system to the booster coordinate system; —Equivalent load of main binding, force component in the X-axis direction in the rocket body coordinate system; —Equivalent load of main binding, force component in the Y-axis direction in the rocket body coordinate system; —Equivalent load of main binding, force component in the Z-axis direction in the rocket body coordinate system; —Main binding load, force component in the Xz axis direction in the boosting coordinate system; —Main binding load, force component in the Yz axis direction in the boosting coordinate system; —Main binding load, force component in the Zz axis direction under the boosting coordinate system.

7. The comprehensive determination method according to any one of claims 1 to 6, characterized in that, The binding mechanism is used to connect the booster and the core stage of the rocket body, so that the two do not move relative to each other and to transmit the interaction force between them during rocket flight.

8. The comprehensive determination method according to any one of claims 1 to 6, characterized in that, The main binding mechanism is a ball joint structure, which constrains three translational degrees of freedom and transmits three translational force loads; the auxiliary binding mechanism is a three-bar linkage, where each bar only bears tensile and compressive loads along the axial direction of the bar.

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