Carrier rocket flight load analysis method based on flight measurement data

Abstract

The invention discloses a carrier rocket flight load analysis method based on flight measurement data, and relates to the technical field of spaceflight, and the method comprises the steps: measuring a flight load in a rocket flight process, and obtaining actual flight strain data and actual flight trajectory data; according to the actual flight strain data and a pre-constructed load-strain corresponding relation, calculating a rocket body total load of each station on the rocket body; calculating the rocket body static load of each station in the actual flight process by using the actual flight trajectory data; subtracting the corresponding static load of the rocket body from the total load of the rocket body at each station to obtain the dynamic load of the rocket body at each station; and optimizing the flight load dynamic load theoretical calculation method by using the rocket body static load of each station and the rocket body dynamic load of each station to obtain an optimized flight load calculation method. The rocket body structure load in the actual flight process can be obtained through load measurement in the flight process, and therefore the static load of actual flight and the dynamic load of actual flight are obtained in a back-stepping mode.

Description

Technical Field

[0001] The present application relates to the field of aerospace technology, and in particular to a method for analyzing the flight load of a launch vehicle based on flight measurement data. Background Art

[0002] During the flight, the launch vehicle is subject to external loads such as engine thrust, aerodynamic force, inertial force and control force. According to the load characteristics, the flight load can be divided into two parts: quasi-static load and dynamic load. For example, the engine rated thrust and steady wind cause longitudinal and lateral static loads; engine ignition, shutdown, separation, etc. will cause axial dynamic loads; transonic pressure pulsation, gusts, etc. during flight will cause lateral dynamic loads. Affected by the elasticity of the rocket body and the accuracy of the external load input, the analysis and evaluation of the dynamic load during flight is more difficult than that of the static load. With the development of large launch vehicles, the elastic frequency of the rocket body has decreased, and the proportion of dynamic loads during flight has increased. The dynamic load may account for 50% or more of the design load. The flight load directly affects the design of the rocket body structure. If the flight load given by the design is too small, it will directly affect the safety of the flight process. If the flight load is too large, the dead weight of the structure will increase, which will affect the launch performance of the launch vehicle.

[0003] Previous flight load analysis mainly relied on theoretical calculation and engineering analysis methods, which are conservative. In order to accurately grasp the rocket body load during flight, it is necessary to analyze the load experienced by the rocket body during actual flight through actual flight measurement parameters, and then optimize the flight load design method, reduce the conservatism of the flight load, and thus improve the carrying capacity of the launch vehicle.

[0004] The traditional flight load analysis method using theoretical calculation has a high accuracy in static load calculation, but has a large deviation in dynamic load calculation, which is mainly restricted by:

[0005] (1) During the design process, external load inputs such as transonic pulsating pressure and gusts during flight are obtained through simulation calculations, wind tunnel tests, or engineering experience. The accuracy of the external loads obtained is limited, which in turn affects the accuracy of flight load calculations.

[0006] (2) The external loads (especially dynamic loads) and the elasticity of the rocket body during flight are both time-varying data. When calculating the actual loads, it is necessary to select characteristic points for enveloping. The calculation method of the structural response under random loads is also conservative to a certain extent.

[0007] Based on the measured flight data, the analysis of the launch vehicle flight load can more accurately evaluate the rocket body flight load and optimize the flight load design method. For example, in the invention patent with application publication number CN116108558A and invention name A method for verifying the static load of a launch vehicle flight, a method for evaluating the static load mainly for the deviation of the overall parameters is introduced, but the analysis method related to the dynamic load part is not involved.

[0008] Therefore, it is necessary to propose a new launch vehicle flight load analysis method based on flight measurement data to solve the above problems. Summary of the invention

[0009] The purpose of this application is to provide a method for analyzing the flight load of a launch vehicle based on flight measurement data, to reversely infer the flight load using the measured data during the flight, and to optimize the design method of the flight load by distinguishing between dynamic loads and static loads, thereby improving the accuracy of the flight load and contributing to the structural optimization of the launch vehicle and the improvement of its carrying capacity.

[0010] To achieve the above-mentioned purpose, the present application provides a method for analyzing the flight load of a launch vehicle based on flight measurement data, comprising the following steps: measuring the flight load during the rocket flight to obtain actual flight strain data and actual flight trajectory data; calculating the total load of the rocket body at each station on the rocket body according to the actual flight strain data and a pre-constructed load-strain correspondence relationship, wherein the total load of the rocket body is the load corresponding to the actual flight strain data in the pre-constructed load-strain correspondence relationship; the total load of the rocket body includes at least: axial force, shear force and bending moment; calculating the static load of the rocket body at each station during the actual flight using the actual flight trajectory data, wherein the static load of the rocket body includes at least: axial force, shear force and bending moment; obtaining the dynamic load of the rocket body at each station by subtracting the corresponding static load of the rocket body from the total load of the rocket body at each station; optimizing the theoretical calculation method of the flight load and dynamic load using the static load of the rocket body at each station and the dynamic load of the rocket body at each station to obtain an optimized flight load calculation method.

[0011] As mentioned above, optimizing the theoretical calculation method of the dynamic load of the flight load by using the static load of the arrow body at each station and the dynamic load of the arrow body at each station at least includes: correcting the elasticity of the arrow body according to the frequency domain characteristics of the measurement data; and correcting the excitation force function of the flight process according to the magnitude of the dynamic load and the distribution of the dynamic load along the arrow body.

[0012] As mentioned above, the specific method for correcting the elasticity of the arrow body according to the frequency domain characteristics of the measurement data is: by performing frequency domain analysis on the dynamic load of the arrow body at each station, the flight spectrum characteristics of the dynamic load of the arrow body at each station are obtained, and the theoretical calculated elastic characteristics of the arrow body are corrected according to the flight spectrum characteristics of the dynamic load of the arrow body at each station.

[0013] As above, the flight spectrum characteristics of the dynamic load of the arrow body at each station corresponding to different frequency bands are obtained by fast Fourier transform.

[0014] As above, the specific method for correcting the excitation force function of the flight process according to the magnitude of the dynamic load and the distribution of the dynamic load along the rocket body is: by comparing the magnitude of the dynamic load of the rocket body at each station in different frequency domains with the magnitude of the dynamic load obtained by the original input, by adjusting the external force function as a whole or adjusting the external force function of different positions of the rocket body according to the distribution of the dynamic load along the rocket body, so that the theoretically calculated dynamic load is close to the dynamic load of the rocket body at each position; the dynamic load of the rocket body at each station obtained by multiple flights is accumulated to obtain the dynamic load envelope during the rocket flight process, thereby optimizing the design load of the rocket body, and then guiding the optimization of the rocket body structure.

[0015] As above, the static load of the arrow body at each station during the actual flight process is calculated by theoretical methods or finite element models using actual flight trajectory data.

[0016] As above, wherein the theoretical method is the existing D'Alembert principle.

[0017] As mentioned above, the typical position of the rocket structure is used as the strain measurement position, and the actual flight strain data of the rocket body structure during the flight is obtained by attaching strain gauges at the strain measurement position, wherein the actual flight strain data at least includes: the axial strain data of the rocket body.

[0018] As mentioned above, the axial strain data of the rocket body at least includes: axial strain data at the fairing position, axial strain data at the instrument cabin position, axial strain data at the interstage position and axial strain data at the tail section position.

[0019] As above, where the shear force Q in the static load of the arrow body at the kth station 1k The calculation formula is: in: is the aerodynamic normal force coefficient acting on the pressure center of the arrow body corresponding to the i-th station; i∈[1,k], k is a natural number, indicating the number of stations; m 1i is the mass of the substation at the ith station; N1 is the derivative of the aerodynamic normal acceleration coefficient; N2 is the derivative of the aerodynamic normal rotation angular acceleration coefficient; x z is the center of mass of the arrow body; i is the line length corresponding to the i-th station; q represents the flight pressure; Sa represents the aerodynamic reference area, that is, the area of ​​the i-th station.

[0020] The beneficial effects achieved by this application are as follows:

[0021] (1) The launch vehicle flight load analysis method based on flight measurement data of the present application obtains the rocket body structure load during the actual flight process through load measurement during the flight, and then reversely infers the actual flight static load and the actual flight dynamic load.

[0022] (2) The launch vehicle flight load analysis method based on flight measurement data of the present application optimizes the flight load design method through the static load of actual flight and the dynamic load of actual flight. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0024] Figure 1 A flow chart of an embodiment of a method for analyzing a launch vehicle's flight load based on flight measurement data;

[0025] Figure 2 A schematic diagram of an embodiment of a pre-built load-strain correspondence;

[0026] Figure 3 A schematic diagram of an embodiment of the process of deriving the shear force caused by aerodynamic forces. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0028] like Figure 1-3 As shown, the present application provides a method for analyzing the flight load of a launch vehicle based on flight measurement data, comprising the following steps:

[0029] S1: Measure the flight load during the rocket flight and obtain the actual flight strain data and actual flight trajectory data.

[0030] Specifically, the typical position of the rocket structure is used as the strain measurement position, and the actual flight strain data of the rocket body structure during the flight is obtained by attaching strain gauges at the strain measurement position, wherein the actual flight strain data at least includes: the axial strain data of the rocket body. The axial strain data of the rocket body at least includes: the axial strain data of the fairing position, the axial strain data of the instrument cabin position, the axial strain data of the interstage position, and the axial strain data of the tail position.

[0031] Furthermore, the middle of the arrow body (i.e., the area with large lateral bending dynamic load) and / or the bottom of the arrow body (i.e., the area with large axial load) are selected as the strain measurement position, and the strain gauge is set in the middle of the arrow body and / or the area with simple structure on the bottom of the arrow body, so that the correspondence between the measured strain data and the load can be more accurate. In addition, since the arrow body load mainly causes axial strain, if the measurement channel is limited, only the axial strain data of the arrow body can be measured.

[0032] During the flight, the actual flight trajectory data of each flight is obtained through telemetry. The actual flight trajectory data at least includes: altitude, speed, engine thrust, aerodynamic force, angle of attack and control force.

[0033] S2: Calculate the total arrow body load at each station on the arrow body according to the actual flight strain data and the pre-constructed load-strain correspondence relationship, wherein the total arrow body load is the load corresponding to the actual flight strain data in the pre-constructed load-strain correspondence relationship; the total arrow body load includes at least: axial force, shear force and bending moment.

[0034] Specifically, through finite element simulation and ground tests, the strain data of typical positions of the rocket structure under different loads are obtained, and the load-strain correspondence of the typical structure is established according to the strain data of the typical positions of the rocket structure, and the load-strain correspondence of the typical structure is used as the pre-constructed load-strain correspondence. The rocket structure is in the elastic range during flight, so the load-strain correspondence is a linear relationship.

[0035] Among them, Figure 2 As shown in the figure, the pre-built load-strain correspondence is compared with the actual flight strain data (ie: Figure 1 The load corresponding to the microstrain in Figure 1 The load in / KN) is taken as the total load of the rocket body.

[0036] Wherein, each station is a different position on the arrow body. For an embodiment of each station, see Figure 3 , for example: Q1, Q2, Q 4-1 and Q4 are all positions, but positions are not limited to Q1, Q2, Q 4-1 and Q4.

[0037] S3: Calculate the static load of the arrow body at each station during the actual flight process using the actual flight trajectory data, wherein the static load of the arrow body includes at least: axial force, shear force and bending moment.

[0038] Furthermore, the static load of the arrow body at each position during the actual flight is calculated using theoretical methods or finite element models using actual flight trajectory data.

[0039] Specifically, through the rocket mass characteristics, engine thrust, aerodynamic force, control force and other external loads, theoretical methods or finite element models are used to calculate the static load of the cross section corresponding to each position of the rocket during flight.

[0040] Furthermore, the theoretical method is the existing D'Alembert principle, but is not limited to the D'Alembert principle. The present application is preferably: calculating the static load of the rocket body during flight by using the D'Alembert principle.

[0041] Among them, taking the transverse shear force as an example, the calculation method of the static load of the rocket body is as follows:

[0042] like Figure 3 As shown, the top of the arrow body is taken as the origin, the length direction of the arrow body from the top of the arrow body to the tail of the arrow body is taken as the X-axis, and the direction perpendicular to the X-axis is taken as the Y-axis, and the Y-axis is located on the right side of the origin.

[0043] During free flight, the shear force Q in the static load of the rocket body at the kth station is 1k The calculation formula is:

[0044]

[0045] in: is the aerodynamic normal force coefficient acting on the pressure center of the arrow body corresponding to the i-th station; i∈[1,k], k is a natural number, indicating the number of stations; m 1i is the mass of the substation at the ith station; N1 is the derivative of the aerodynamic normal acceleration coefficient; N2 is the derivative of the aerodynamic normal rotation angular acceleration coefficient; x z is the center of mass of the arrow body; i is the line length corresponding to the i-th station; q represents the flight pressure; Sa represents the aerodynamic reference area, that is, the area of ​​the i-th station.

[0046] in, is the derivative of the normal force coefficient corresponding to the i-th station.

[0047] Assuming that the arrow body is divided into S+1 positions, the overall aerodynamic normal force coefficient derivative of the arrow body is: Where S is a natural number, i∈[1,S+1]. The derivative of the aerodynamic normal force coefficient acts on the pressure center of the arrow body, and the derivative of the aerodynamic normal force coefficient is divided by the mass m1 of the arrow body (where And m 1i is the substation quality at the ith station), we can get It is called the derivative of the aerodynamic normal acceleration coefficient. The normal acceleration of the rocket body caused by the aerodynamic normal force is: Arrow body center of mass Arrow body pressure The moment of inertia of the arrow body J = (x z -x i ) 2 ·m 1i , thus obtaining the derivative of the aerodynamic normal rotation angular acceleration coefficient The angular acceleration of the rocket body caused by the aerodynamic normal force is ).

[0048] S4: The total arrow body load at each station is subtracted from the corresponding arrow body static load to obtain the arrow body dynamic load at each station.

[0049] Specifically, the dynamic load of the arrow body at each station obtained by subtracting the corresponding static load of the arrow body from the total load of the arrow body at each station is the dynamic load of the arrow body during the actual flight.

[0050] S5: The flight load and dynamic load theoretical calculation method is optimized by using the static load of the arrow body at each station and the dynamic load of the arrow body at each station to obtain an optimized flight load calculation method.

[0051] Specifically, the flight load dynamic load theoretical calculation method includes: a static load calculation method and a dynamic load calculation method.

[0052] Among them, the static load calculation method is: through the rocket mass characteristics, engine thrust, aerodynamic force, control force and other external loads, use theoretical methods or finite element models to calculate the static load of the cross-section corresponding to each position of the rocket during the flight.

[0053] The dynamic load calculation method is: through the dynamic characteristics of the rocket, transonic pulsating pressure, gust external load, through theoretical methods or finite element models to calculate the dynamic load of the cross section corresponding to each position of the rocket during flight. The dynamic load calculation principle is:

[0054] For an elastic beam with infinite degrees of freedom, the dynamic load calculation method is discretized into the elastic vibration equation of a multi-degree-of-freedom system, which is expressed as follows:

[0055]

[0056] in, is the generalized acceleration corresponding to the j-th vibration mode; is the generalized velocity corresponding to the j-th vibration mode; q j is the generalized displacement corresponding to the j-th vibration mode; ξ j is the j-th order elastic vibration modal damping of the beam; ω j is the j-th order elastic vibration circular frequency; M j is the generalized mass corresponding to the j-th vibration mode, φ j is the j-th order elastic vibration mode of the beam, x represents the cross section at any station; l is the length of the arrow body; represents the j-th order generalized mass of the entire rocket beam calculated by integration; m(x) represents the mass characteristic of the rocket body; dx represents the integral along the length of the rocket; N j (t) represents the external generalized force corresponding to the j-th vibration mode; t represents time.

[0057] The solution of the elastic vibration equation depends on the exciting force f(x,t). j When determined, the elastic displacement of the beam is obtained Among them, q j (x) represents the jth-order generalized coordinate corresponding to the x-coordinate of the rocket body. The shear force and bending moment values ​​at the section x at any position of the rocket are obtained by the following calculation formula. The expression of the shear force Q(x) at the section x at any position of the rocket is:

[0058]

[0059] Where EI is the bending stiffness of the arrow body, which is set as a constant; is the symbol of partial differential in mathematics; y represents the deflection of the beam; φ j (x) is the j-th elastic vibration mode of the beam, x represents the cross section at any station; q j represents the generalized displacement corresponding to the j-th vibration mode; Q j ′ represents the vibration mode φ j The corresponding modal shear force.

[0060] Among them, the expression of the bending moment M(x) at the section x of any position of the rocket is:

[0061]

[0062] Where EI is the bending stiffness of the arrow body, which is set as a constant; M j ′ is related to the vibration mode φ j The corresponding modal bending moment.

[0063] Specifically, when the bending stiffness EI of the rocket body is not a constant, the i-th order elastic vibration circular frequency ω is obtained from the finite element calculation of the rocket body lateral vibration: j 、Vibration type φ j , and vibration mode φ jThe corresponding modal shear force Q j ′ and vibration mode φ j The corresponding modal bending moment M j ′ data.

[0064] If the excitation force function f(x,t) = F(x)ξ(t), where F(x) represents the external force function that varies at different positions along the arrow body; ξ(t) is a random function of time. It can be shown that the displacement mean square response for:

[0065]

[0066] In the formula, represents integral calculation; f(ω) is the input power spectral density; z(ω) is the arrow body transfer function.

[0067] in:

[0068]

[0069] Where f(ω) is the input power spectrum density; l is the length of the arrow body; φ j (x) is the j-th order elastic vibration mode of the beam, x represents the cross section at any station; M j is the generalized mass corresponding to the j-th vibration mode; ω j is the j-th order elastic vibration circular frequency; ω represents the circular frequency.

[0070] Among them, the j-th order generalized displacement mean square response for:

[0071]

[0072] In the formula, ξ j represents the j-th order elastic vibration modal damping of the beam; f(ω j ) represents the input power spectral density; π is pi.

[0073] Furthermore, the theoretical calculation method of the dynamic load of the flight load is optimized by using the static load of the arrow body at each station and the dynamic load of the arrow body at each station (i.e., load optimization), which at least includes: correcting the elasticity of the arrow body according to the frequency domain characteristics of the measurement data; and correcting the excitation force function of the flight process according to the magnitude of the dynamic load and the distribution of the dynamic load along the arrow body.

[0074] Furthermore, the specific method for correcting the elasticity of the arrow body according to the frequency domain characteristics of the measurement data is: by performing frequency domain analysis on the dynamic load of the arrow body at each station, the flight spectrum characteristics of the dynamic load of the arrow body at each station are obtained, and the theoretically calculated elastic characteristics of the arrow body are corrected according to the flight spectrum characteristics of the dynamic load of the arrow body at each station.

[0075] Specifically, by performing frequency domain analysis on the dynamic load of the arrow body at each position, the distribution characteristics of the dynamic load of the arrow body at each position at different frequencies can be obtained. The distribution is larger at the first three natural frequencies of the arrow body. Therefore, the theoretically calculated elastic characteristics of the arrow body are corrected according to the flight frequency spectrum characteristics of the dynamic load of the arrow body at each position.

[0076] Furthermore, the flight spectrum characteristics of the dynamic load of the rocket body at each station corresponding to different frequency bands are obtained through FFT transformation (Fast Fourier Transform) for use in subsequent optimization.

[0077] Furthermore, according to the magnitude of the dynamic load and the distribution of the dynamic load along the rocket body, the specific method for correcting the excitation force function of the flight process is as follows: by comparing the magnitude of the dynamic load of the rocket body at each station in different frequency domains with the magnitude of the dynamic load obtained by the original input, the external force function is adjusted as a whole or the external force function of different stations of the rocket body is adjusted according to the distribution of the dynamic load along the rocket body, so that the theoretically calculated dynamic load is close to the dynamic load of the rocket body at each station; the dynamic load of the rocket body at each station obtained through multiple flights is accumulated to obtain the dynamic load envelope during the rocket flight process, so as to optimize the design load of the rocket body, and then guide the optimization of the rocket body structure.

[0078] Specifically, the present application mainly optimizes the dynamic load, and the optimized flight load calculation method is more accurate.

[0079] The beneficial effects achieved by this application are as follows:

[0080] (1) The launch vehicle flight load analysis method based on flight measurement data of the present application obtains the rocket body structure load during the actual flight process through load measurement during the flight, and then reversely infers the actual flight static load and the actual flight dynamic load.

[0081] (2) The launch vehicle flight load analysis method based on flight measurement data of the present application optimizes the flight load design method through the static load of actual flight and the dynamic load of actual flight.

[0082] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the scope of protection of the present application is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application. Obviously, those skilled in the art may make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the protection scope of the present application and its equivalent technology, the present application is also intended to include these modifications and variations.

Claims

1. A method for analyzing the flight load of a launch vehicle based on flight measurement data, characterized in that: The steps include: Measure the flight load of the rocket during flight and obtain actual flight strain data and actual flight trajectory data; Calculating the total load of the arrow body at each station on the arrow body according to the actual flight strain data and the pre-constructed load-strain correspondence relationship, wherein the total load of the arrow body is the load corresponding to the actual flight strain data in the pre-constructed load-strain correspondence relationship; the total load of the arrow body includes at least: axial force, shear force and bending moment; Using actual flight trajectory data, the static load of the arrow body at each station during the actual flight process is calculated, wherein the static load of the arrow body includes at least: axial force, shear force and bending moment; The dynamic load of the arrow body at each station is obtained by subtracting the corresponding static load of the arrow body from the total load of the arrow body at each station. The static load of the rocket body at each station and the dynamic load of the rocket body at each station are used to optimize the theoretical calculation method of the flight load and dynamic load, and the optimized flight load calculation method is obtained.

2. The method for analyzing the flight load of a launch vehicle based on flight measurement data according to claim 1, characterized in that: Optimizing the theoretical calculation method of the flight load dynamic load by using the static load of the arrow body at each station and the dynamic load of the arrow body at each station at least includes: correcting the elasticity of the arrow body according to the frequency domain characteristics of the measurement data; and correcting the excitation force function of the flight process according to the dynamic load magnitude and the distribution of the dynamic load along the arrow body.

3. The method for analyzing the flight load of a launch vehicle based on flight measurement data according to claim 2, characterized in that: The specific method for correcting the elasticity of the arrow body according to the frequency domain characteristics of the measurement data is as follows: by performing frequency domain analysis on the dynamic load of the arrow body at each station, the flight spectrum characteristics of the dynamic load of the arrow body at each station are obtained, and the theoretically calculated elastic characteristics of the arrow body are corrected according to the flight spectrum characteristics of the dynamic load of the arrow body at each station.

4. The method for analyzing the flight load of a launch vehicle based on flight measurement data according to claim 3, characterized in that: The flight spectrum characteristics of the rocket body dynamic load at each station corresponding to different frequency bands are obtained through fast Fourier transform.

5. The method for analyzing the flight load of a launch vehicle based on flight measurement data according to claim 2, characterized in that: The specific method for correcting the excitation force function of the flight process according to the magnitude of the dynamic load and the distribution of the dynamic load along the rocket body is as follows: by comparing the magnitude of the dynamic load of the rocket body at each station in different frequency domains with the magnitude of the dynamic load obtained by the original input, the external force function is adjusted as a whole or the external force function of different stations of the rocket body is adjusted according to the distribution of the dynamic load along the rocket body, so that the theoretically calculated dynamic load is close to the dynamic load of the rocket body at each station; the dynamic load of the rocket body at each station obtained through multiple flights is accumulated to obtain the dynamic load envelope during the rocket flight process, so as to optimize the design load of the rocket body and guide the optimization of the rocket body structure.

6. The method for analyzing the flight load of a launch vehicle based on flight measurement data according to claim 1, characterized in that: The static load of the arrow body at each position during the actual flight process is calculated using theoretical methods or finite element models using actual flight trajectory data.

7. The method for analyzing the flight load of a launch vehicle based on flight measurement data according to claim 6, characterized in that: The theoretical method is the existing D'Alembert principle.

8. The method for analyzing the flight load of a launch vehicle based on flight measurement data according to claim 1, characterized in that: The typical positions of the rocket structure are used as strain measurement positions, and the actual flight strain data of the rocket body structure during flight is obtained by attaching strain gauges at the strain measurement positions, wherein the actual flight strain data at least includes: the axial strain data of the rocket body.

9. The method for analyzing the flight load of a launch vehicle based on flight measurement data according to claim 8, characterized in that: The axial strain data of the rocket body at least includes: axial strain data at the fairing position, axial strain data at the instrument cabin position, axial strain data at the interstage position and axial strain data at the tail section position.

10. The method for analyzing launch vehicle flight load based on flight measurement data according to claim 1, characterized in that: Shear force Q in the static load of the rocket body at the kth station 1k The calculation formula is: in: is the aerodynamic normal force coefficient acting on the pressure center of the arrow body corresponding to the i-th station; i∈[1,k], k is a natural number, indicating the number of stations; m 1i is the mass of the substation at the ith station; N1 is the derivative of the aerodynamic normal acceleration coefficient; N2 is the derivative of the aerodynamic normal rotation angular acceleration coefficient; x z is the center of mass of the arrow body; x i is the line length corresponding to the i-th station; q represents the flight pressure; Sa represents the aerodynamic reference area, that is, the area of ​​the i-th station.

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