Arresting hook bending fatigue spectrum calculation method and system

Abstract

The invention belongs to the technical field of shipboard aircraft landing gear fatigue design, and particularly relates to an arresting hook bending fatigue spectrum calculation method and system.The arresting hook bending fatigue spectrum calculation method comprises the steps that a spring unit and an arresting hook are combined to establish an arresting hook assembly kinetic model, and then a front landing gear and main landing gear kinetic model and a rigid airframe model of the arresting hook are established; a full-aircraft dynamic model is assembled; and applying an arresting force curve at a hook head of the arresting hook, solving, and finally forming an arresting hook bending spectrum through a time domain curve of an arresting hook damper. On the basis of GJB 67.6A-2008 stipulation, the arresting hook bending spectrum is additionally adopted for the arresting hook fatigue design spectrum, and the stress state of the arresting hook can be truly reflected. The arresting hook bending spectrum and the GJB 67.6A-2008 specified spectrum are combined for arresting hook structural part design or fatigue verification, the service life of the arresting hook can be reasonably determined, and aircraft safety is guaranteed.

Description

Technical Field

[0001] The present application belongs to the technical field of fatigue design of carrier-based aircraft landing gear, and in particular relates to a method and system for calculating bending fatigue spectrum of an arresting hook. Background Art

[0002] When the aircraft lands, the arresting hook engages with the arresting device cable on the aircraft carrier, and the arresting device absorbs and consumes the aircraft's directional kinetic energy, forcing the aircraft to stop in a short distance. The arresting load generated during this period is transmitted to the rear fuselage reinforcement frame through the arresting hook. The buffer is used to suppress the arresting hook from hitting the ship and rebounding, so that it can recover to fit the ship surface as soon as possible.

[0003] Generally, the arresting hook load spectrum calculation is carried out in accordance with GJB67.6A-2008. The provisions of the arresting hook load spectrum in GJB67.6A-2008 are as follows: for 90% of the arrested landings, the horizontal component of the arresting hook arresting resistance should be equal to the limit load. For the other 10% of the arrested landings, the force corresponding to the 90% upper percentile of the statistical distribution of the arresting resistance of the arresting device in the relevant standards under the 90% confidence level should be taken. For 90% of the arrested landings, the lateral force should be 0.6 times the landing design weight. For the other 10% of the arrested landings, the lateral force should be 1.0 times the landing design weight. The resultant force P on the arresting hook should be applied through a point half the radius of the cable groove away from the center line of the hook handle. The resultant force P should be applied in the following order: 0→P→0.5P→P→0.5P→P→0.

[0004] The arresting hook of a carrier aircraft usually hits the deck first and then slides the cable. After the arresting hook hits the deck or the cable, it swings up quickly, and the damper load reaches the maximum value. At this time, the arresting hook is in the maximum bending stress state.

[0005] GJB67.6A-2008 stipulates the horizontal load of the arresting force after the arresting hook is hung on the arresting cable, but does not stipulate the bending stress state of the arresting hook.

[0006] Therefore, how to design an arresting hook load spectrum that is more in line with the actual loading scenario of the arresting hook is a problem that needs to be solved. Summary of the invention

[0007] The purpose of the present application is to provide a method and system for calculating the bending fatigue spectrum of an arresting hook, so as to solve the problem that the existing arresting hook load spectrum fails to truly reflect the stress state of the arresting hook.

[0008] The technical solution of the present application is: a method for calculating the bending fatigue spectrum of an arresting hook, comprising:

[0009] The initial inflation pressure, compressed area, initial inflation volume, compression stroke of the piston rod and oil damping coefficient of the spring damper are obtained to establish a spring damper unit. The spring damper unit is then combined with the corresponding spring structure parameters to form a spring unit. The spring unit is combined with the arresting hook to establish the dynamic model of the arresting hook assembly.

[0010] The oil-gas performance of the oil-gas buffer is simulated by the spring damping unit, and the tire characteristics are simulated by the spring unit, and the dynamic models of the front landing gear and the main landing gear are established respectively;

[0011] The center of gravity position, the connection position between the landing gear and the fuselage, and the connection position between the arresting hook and the fuselage are defined respectively, and the rigid body model of the arresting hook is established;

[0012] The arresting hook assembly dynamics model, the front landing gear and main landing gear dynamics model, and the rigid body model are assembled into a full aircraft dynamics model using the energy-reflecting actual load transfer relationship;

[0013] The arresting hook is set to be in a fully extended and lowered state, the middle weight parameter is applied at the center of gravity of the whole aircraft dynamics model, the initial condition is applied at the center of gravity, the arresting resistance curve is applied at the hook head, and the solution is performed to obtain the time domain curve of the arresting hook damper;

[0014] Extract the maximum value F of the axial force of the arresting hook damper through the time domain curve max The angle α' and the arresting force L' at the same moment form the bending spectrum of the arresting hook.

[0015] Preferably, in the spring damping unit, the spring force F 1 =f(p 0 ,A,V 0 ,s), damping force

[0016]

[0017] Where: p 0 is the initial inflation pressure, A is the compressed area, V 0 is the initial inflation volume, s is the compression stroke of the piston rod, is the derivative of the compression stroke, and κ is the oil damping coefficient.

[0018] Preferably, the spring force in the tire characteristic is: T 1 =f(δ); where δ is the compression of the tire.

[0019] Preferably, the time domain curve includes the axial force F, the angle α between the damper and the horizontal plane of the aircraft structure, and the arresting force L.

[0020] Preferably, the weight parameters include weight and inertia; the initial conditions include the combined speed V E , sinking speed VV 、Aircraft pitch angle θ P .

[0021] Preferably, the arresting resistance L in the arresting resistance curve is f(x), where x is the distance the aircraft glides forward.

[0022] The arresting hook bending fatigue spectrum calculation method and system of the present application adds the arresting hook bending spectrum of the present application to the arresting hook fatigue design spectrum on the basis of GJB 67.6A-2008, which can truly reflect the stress state of the arresting hook. The arresting hook bending spectrum is combined with the spectrum specified in GJB 67.6A-2008 to design the arresting hook structure or perform fatigue verification, which can reasonably determine the arresting hook life and ensure the safety of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0024] Figure 1 It is a schematic diagram of the dynamic model of the arresting hook assembly in the background technology;

[0025] Figure 2 This is a schematic diagram of the overall process of this application;

[0026] Figure 3 This is a schematic diagram of the dynamic model of the arresting hook assembly of this application;

[0027] Figure 4 This is a schematic diagram of the arresting resistance curve for this application;

[0028] Figure 5 This is a schematic diagram of arresting hook loading for this application. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] A method for calculating the bending fatigue spectrum of an arresting hook, such as Figure 2 As shown, the following steps are included:

[0031] Step S100, obtaining the initial inflation pressure, compressed area, initial inflation volume, compression stroke of the piston rod and oil damping coefficient of the spring damping, establishing a spring damping unit, and then combining the spring damping unit with the corresponding spring structural parameters to form a spring unit, and combining the spring unit with the arresting hook to establish the arresting hook assembly dynamics model. The spring structural parameters include tire compression, etc.

[0032] The dynamic model of the arresting hook assembly is as follows: Figure 3 As shown, the damper is simulated by a spring damper unit, and the spring damper unit is specifically represented by a spring force and a resistance force.

[0033] Wherein, the spring force F 1 =f(p 0 ,A,V 0 ,s), damping force

[0034] Where: p 0 is the initial inflation pressure, A is the compressed area, V 0 is the initial inflation volume, s is the compression stroke of the piston rod, is the derivative of the compression stroke, and κ is the oil damping coefficient.

[0035] Step S200, similar to the dynamic models of the front landing gear and the main landing gear, the oil-gas performance of the oil-gas buffer is simulated by the spring damping unit, and the tire characteristics are simulated by the spring unit, and the dynamic models of the front landing gear and the main landing gear are established respectively.

[0036] Among them, the spring force F of the oil-gas buffer 2 =f(p 0 ,A,V 0 ,s), damping force

[0037] Where: p 0 is the initial inflation pressure, A is the compressed area, V 0 is the initial inflation volume, s is the compression stroke of the piston rod, is the derivative of the compression stroke, and κ is the oil damping coefficient.

[0038] The spring force in the tire characteristics is: T 1 =f(δ); where δ is the compression of the tire.

[0039] Step S300, respectively defining the center of gravity position, the connection position between the landing gear and the fuselage, and the connection position between the arresting hook and the fuselage, and establishing a rigid body model of the arresting hook.

[0040] The rigid body model can reflect the state in which the arresting hook does not change in shape and size when subjected to external force. Combined with the dynamic models of the front landing gear and main landing gear, it can fully reflect the overall state of the arresting hook.

[0041] Step S400, assembling the arresting hook assembly dynamics model, the front landing gear and main landing gear dynamics models, and the rigid body model into a full aircraft dynamics model using a relationship that can reflect the actual load transfer.

[0042] The actual transmission relationship of energy reaction is to establish the energy transfer equations between each other, so as to establish the node correspondence of each model, wherein the input and output relationship of energy of each model can be obtained by collecting existing data.

[0043] Step S500, setting the arresting hook to be in a fully extended and lowered state, applying a medium weight parameter at the center of gravity of the whole aircraft dynamics model, applying an initial condition at the center of gravity, applying an arresting resistance curve at the hook head of the arresting hook, and solving to obtain a time domain curve of the arresting hook damper axial force F, the angle α between the damper and the horizontal plane of the aircraft structure, and the arresting resistance L;

[0044] The arresting hook is in the fully extended and lowered state. The weight parameter (excluding the weight parameters of the landing gear and the arresting hook) is applied to the center of gravity of the whole aircraft dynamics model. The weight parameter includes weight and inertia.

[0045] Initial conditions are applied at the center of gravity, including the combined speed V on the ship. E , sinking speed V V 、Aircraft pitch angle θ P .

[0046] The arresting resistance curve is applied to the hook head of the arresting hook, and the arresting resistance L = f(x), where x is the distance the aircraft glides forward.

[0047] Step S600, extracting the maximum value F of the axial force of the arresting hook damper max The angle α' and the arresting force L' at the same time form the arresting hook bending spectrum and the real stress state of the arresting hook.

[0048] Through the above design, the arresting hook fatigue design spectrum is added with the arresting hook bending spectrum of the present application on the basis of the provisions of GJB 67.6A-2008, which can truly reflect the stress state of the arresting hook. The arresting hook bending spectrum is combined with the spectrum specified in GJB67.6A-2008 to design the arresting hook structure or perform fatigue verification, which can reasonably determine the arresting hook life and ensure the safety of the aircraft.

[0049] As a specific implementation, a system for calculating bending fatigue spectrum of an arresting hook is also included, including:

[0050] The module for establishing the arresting hook model obtains the initial inflation pressure, compressed area, initial inflation volume, compression stroke of the piston rod and oil damping coefficient of the spring damping, establishes a spring damping unit, and then combines the spring damping unit with the corresponding spring structure parameters to form a spring unit. The spring unit is combined with the arresting hook to establish the dynamic model of the arresting hook assembly.

[0051] The landing gear model building module simulates the oil-gas performance of the oil-gas buffer through the spring damping unit, simulates the tire characteristics through the spring unit, and establishes the dynamic models of the front landing gear and the main landing gear respectively;

[0052] The rigid body model building module defines the center of gravity position, the connection position between the landing gear and the body, and the connection position between the arresting hook and the body, and builds the rigid body model of the arresting hook;

[0053] The whole aircraft dynamics model building module assembles the arresting hook assembly dynamics model, the front landing gear and main landing gear dynamics model, and the rigid body model into the whole aircraft dynamics model by using the actual load-transfer relationship;

[0054] The time domain curve establishment module sets the arresting hook to be in a fully extended and lowered state, applies the middle weight parameter at the center of gravity of the whole aircraft dynamics model, applies the initial condition at the center of gravity, applies the arresting resistance curve at the hook head, and solves it to obtain the time domain curve of the arresting hook damper;

[0055] The arresting hook bending spectrum establishment module extracts the maximum value F of the axial force of the arresting hook damper through the time domain curve max The angle α' and the arresting force L' at the same moment form the bending spectrum of the arresting hook.

[0056] Preferably, in the spring damping unit, the spring force F 1 =f(p 0 ,A,V 0 ,s), damping force

[0057]

[0058] Where: p 0 is the initial inflation pressure, A is the compressed area, V 0 is the initial inflation volume, s is the compression stroke of the piston rod, is the derivative of the compression stroke, and κ is the oil damping coefficient.

[0059] Preferably, the spring force in the tire characteristic is: T 1 =f(δ); where δ is the compression of the tire.

[0060] Preferably, the time domain curve includes the axial force F, the angle α between the damper and the horizontal plane of the aircraft structure, and the arresting force L.

[0061] Preferably, the weight parameters include weight and inertia; the initial conditions include the combined speed V E , sinking speed V V 、Aircraft pitch angle θ P .

[0062] Preferably, the arresting resistance L in the arresting resistance curve is f(x), where x is the distance the aircraft glides forward.

[0063] As a specific implementation method, the following is described with a specific example:

[0064] The bending fatigue spectrum calculation of the arresting hook of a certain type of aircraft is carried out according to the technical solution in step S500.

[0065] The weight is the maximum landing weight G ZLmax 、V E =190km / h, V V =3.6m / s,θ P =3°, the arresting resistance curve is as follows Figure 4 shown.

[0066] By solving the whole machine dynamics model, it is found that the damper axial force reaches the maximum value F max When α'=33°, the resistance along the hook rod axis is L'=47kN. The loading diagram is as follows Figure 5 As shown, the moment around the connection point O between the arresting hook and the fuselage is balanced by the inertial force, which is the same as the actual state, and therefore can better reflect the real state of the arresting hook.

[0067] Finally, it should be noted that: the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0068] Finally: 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 principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for calculating bending fatigue spectrum of an arresting hook, characterized in that: include: The initial inflation pressure, compressed area, initial inflation volume, compression stroke of the piston rod and oil damping coefficient of the spring damper are obtained to establish a spring damper unit. The spring damper unit is then combined with the corresponding spring structure parameters to form a spring unit. The spring unit is combined with the arresting hook to establish the dynamic model of the arresting hook assembly. The oil-gas performance of the oil-gas buffer is simulated by the spring damping unit, and the tire characteristics are simulated by the spring unit, and the dynamic models of the front landing gear and the main landing gear are established respectively; The center of gravity position, the connection position between the landing gear and the fuselage, and the connection position between the arresting hook and the fuselage are defined respectively, and the rigid body model of the arresting hook is established; The arresting hook assembly dynamics model, the front landing gear and main landing gear dynamics model, and the rigid body model are assembled into a full aircraft dynamics model using the energy-reflecting actual load transfer relationship; The arresting hook is set to be in a fully extended and lowered state, the middle weight parameter is applied at the center of gravity of the whole aircraft dynamics model, the initial condition is applied at the center of gravity, the arresting resistance curve is applied at the hook head, and the solution is performed to obtain the time domain curve of the arresting hook damper; Extract the maximum value F of the axial force of the arresting hook damper through the time domain curve max The angle α' and the arresting force L' at the same moment form the bending spectrum of the arresting hook.

2. The method for calculating the bending fatigue spectrum of the arresting hook according to claim 1, characterized in that: In the spring damping unit, the spring force F1 = f(p0, A, V0, s), the damping force Where: p0 is the initial inflation pressure, A is the compression area, V0 is the initial inflation volume, s is the compression stroke of the piston rod, is the derivative of the compression stroke, and κ is the oil damping coefficient.

3. The method for calculating the bending fatigue spectrum of the arresting hook according to claim 1, characterized in that: The spring force in the tire characteristic is: T1 = f(δ); where: δ is the compression of the tire.

4. The method for calculating the bending fatigue spectrum of the arresting hook according to claim 1, characterized in that: The time domain curve includes the axial force F, the angle α between the damper and the horizontal plane of the aircraft structure, and the arresting force L.

5. The method for calculating the bending fatigue spectrum of the arresting hook according to claim 1, characterized in that: The weight parameters include weight and inertia; the initial conditions include the combined speed V E , sinking speed V V 、Aircraft pitch angle θ P .

6. The method for calculating the bending fatigue spectrum of the arresting hook according to claim 1, characterized in that: The arresting resistance L in the arresting resistance curve is f(x), where x is the distance the aircraft glides forward.

7. A system for calculating bending fatigue spectrum of an arresting hook, using the calculation method according to any one of claims 1 to 6, characterized in that: include: The module for establishing the arresting hook model obtains the initial inflation pressure, compressed area, initial inflation volume, compression stroke of the piston rod and oil damping coefficient of the spring damping, establishes a spring damping unit, and then combines the spring damping unit with the corresponding spring structure parameters to form a spring unit. The spring unit is combined with the arresting hook to establish the dynamic model of the arresting hook assembly. The landing gear model building module simulates the oil-gas performance of the oil-gas buffer through the spring damping unit, simulates the tire characteristics through the spring unit, and establishes the dynamic models of the front landing gear and the main landing gear respectively; The rigid body model building module defines the center of gravity position, the connection position between the landing gear and the body, and the connection position between the arresting hook and the body, and builds the rigid body model of the arresting hook; The whole aircraft dynamics model building module assembles the arresting hook assembly dynamics model, the front landing gear and main landing gear dynamics model, and the rigid body model into the whole aircraft dynamics model by using the actual load-transfer relationship; The time domain curve establishment module sets the arresting hook to be in a fully extended and lowered state, applies the middle weight parameter at the center of gravity of the whole aircraft dynamics model, applies the initial condition at the center of gravity, applies the arresting resistance curve at the hook head, and solves it to obtain the time domain curve of the arresting hook damper; Arresting hook bending spectrum establishment module, extracting the maximum value F of the axial force of the arresting hook damper through the time domain curve max The angle α' and the arresting force L' at the same moment form the bending spectrum of the arresting hook.

8. The method for calculating the bending fatigue spectrum of the arresting hook according to claim 7, characterized in that: In the spring damping unit, the spring force F1 = f(p0, A, V0, s), the damping force Where: p0 is the initial inflation pressure, A is the compression area, V0 is the initial inflation volume, s is the compression stroke of the piston rod, is the derivative of the compression stroke, and κ is the oil damping coefficient.

9. The method for calculating the bending fatigue spectrum of the arresting hook according to claim 7, characterized in that: The spring force in the tire characteristic is: T1 = f(δ); where: δ is the compression of the tire.

10. The method for calculating the bending fatigue spectrum of an arresting hook according to claim 7, characterized in that: The time domain curve includes the axial force F, the angle α between the damper and the horizontal plane of the aircraft structure, and the arresting force L.

11. The method for calculating the bending fatigue spectrum of an arresting hook according to claim 7, characterized in that: The weight parameters include weight and inertia; the initial conditions include the combined speed V E , sinking speed V V 、Aircraft pitch angle θ P .

12. The method for calculating the bending fatigue spectrum of an arresting hook according to claim 7, characterized in that: The arresting resistance L in the arresting resistance curve is f(x), where x is the distance the aircraft glides forward.

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