Method and system for measuring internal pressure of single-cavity undercarriage buffer during aircraft landing

Abstract

The invention belongs to the field of aviation structure design, and particularly relates to a method and system for measuring the internal pressure of a single-cavity undercarriage buffer during aircraft landing. Stress analysis is conducted on a piston rod, friction force between the piston rod and a plunger is ignored, and all loads of axial resultant force of the piston rod are determined; comprise the sum of the load of the air cavity acting on the piston rod in the circumferential direction, the load of oil acting on the bottom of the piston rod and the load of air cavity gas acting on the oil needle; determining gas cavity pressure according to the ideal gas state equation; the air cavity acts on the annular load of the piston rod, and the oil acts on the load of the bottom of the piston rod. And substituting the load of the gas of the gas cavity acting on the oil needle and the pressure of the gas cavity into the axial resultant force equation of the piston rod to obtain the pressure of the oil cavity. By establishing an axial force balance equation of the piston rod of the buffer, an expression of the internal pressure of the buffer during landing of the single-cavity undercarriage is given, and the internal pressure of the buffer during landing of an aircraft can be conveniently and quickly calculated.

Description

Technical Field

[0001] This application belongs to the field of aerospace structural design, and specifically relates to a method and system for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing. Background Technology

[0002] A schematic diagram of a single-chamber hydropneumatic landing gear is shown below. Figure 1 As shown, the air chamber is located at the top of the buffer, and the oil chamber is located at the bottom. A perforated baffle is installed between the plunger connected to the outer cylinder. The holes on the baffle are called oil holes. When the aircraft landing gear struts are compressed during landing, oil flows through the oil holes, generating damping force. The back-and-forth flow of oil through the oil holes absorbs and dissipates most of the landing impact energy. The design operating conditions of the internal components of the landing gear are usually caused by the pressure difference between the air chamber and the oil chamber. Therefore, it is necessary to calculate the pressure of the air chamber and oil chamber during landing to verify the strength of the internal components of the buffer. Summary of the Invention

[0003] To address the aforementioned issues, this application provides a method and system for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing, thereby resolving the problem of difficulty in accurately verifying the strength of internal components of the buffer in the prior art.

[0004] The technical solution of this application is: a method for managing the internal pressure of a single-chamber landing gear buffer during aircraft landing, comprising:

[0005] Force analysis is performed on the piston rod, ignoring the friction between the piston rod and the plunger, to determine the resultant force in the piston rod axially, including: the load of the gas chamber acting on the piston rod in the circumferential direction, the load of the oil acting on the bottom of the piston rod, and the load of the gas in the gas chamber acting on the oil needle.

[0006] Determine the pressure in the gas chamber based on the ideal gas law;

[0007] Substituting the loads acting on the piston rod circumferentially by the gas chamber, the loads acting on the bottom of the piston rod by the oil, the load of the gas in the gas chamber acting on the oil needle, and the gas chamber pressure into the equation for the axial resultant force of the piston rod, we obtain the oil chamber pressure.

[0008] Preferably, The load exerted by the air chamber on the piston rod in the circumferential direction is expressed as:

[0009] ;

[0010] in The air chamber pressure, The outer radius of the piston rod. Let be the inner radius of the piston rod.

[0011] Preferably, The load exerted by the oil on the bottom of the piston rod is expressed as:

[0012] ;

[0013] in For oil pressure, The cross-sectional area of ​​the needle oil is related to the compression stroke of the buffer. Related.

[0014] Preferably, The load exerted by the gas in the gas chamber on the oil needle is expressed as:

[0015] .

[0016] Preferably, the ideal gas law is: air chamber pressure The expression is:

[0017] ;

[0018] In the formula, The constant represents the air variability index. The initial pressure of the air chamber. This represents the initial volume of the air cavity.

[0019] Preferably, the expression for the oil cavity pressure is:

[0020] ;

[0021] In the formula, This represents the component of the vertical ground load on the buffer strut axis during landing.

[0022] Another technical solution of this application is: a system for managing the internal pressure of a single-chamber landing gear buffer during aircraft landing, comprising:

[0023] The piston rod resultant force calculation module is used to perform force analysis on the piston rod, ignore the friction between the piston rod and the plunger, and determine the various loads of the resultant force in the axial direction of the piston rod, including: the load of the gas chamber acting on the piston rod in the circumferential direction, the load of the oil acting on the bottom of the piston rod, and the sum of the load of the gas in the gas chamber acting on the oil needle.

[0024] The gas chamber pressure calculation module is used to determine the gas chamber pressure based on the ideal gas law.

[0025] The oil chamber pressure calculation module is used to calculate the circumferential load of the gas chamber on the piston rod and the load of the oil on the bottom of the piston rod. The load of the gas in the gas chamber acting on the oil needle and the gas chamber pressure are substituted into the axial resultant force equation of the piston rod to obtain the oil chamber pressure.

[0026] Preferably, The load exerted by the air chamber on the piston rod in the circumferential direction is expressed as:

[0027] ;

[0028] in The air chamber pressure, The outer radius of the piston rod. Let be the inner radius of the piston rod.

[0029] Preferably, The load exerted by the oil on the bottom of the piston rod is expressed as:

[0030] ;

[0031] in For oil pressure, The cross-sectional area of ​​the needle oil is related to the compression stroke of the buffer. Related.

[0032] Preferably, The load exerted by the gas in the gas chamber on the oil needle is expressed as:

[0033] .

[0034] Preferably, the ideal gas law is: air chamber pressure The expression is:

[0035] ;

[0036] In the formula, The constant represents the air variability index. The initial pressure of the air chamber. This represents the initial volume of the air cavity.

[0037] Preferably, the expression for the oil cavity pressure is:

[0038] ;

[0039] In the formula, This represents the component of the vertical ground load on the buffer strut axis during landing.

[0040] The method and system for controlling the internal pressure of a single-chamber landing gear buffer during landing, as described in this application, have the following advantages:

[0041] By establishing the axial force balance equation of the buffer piston rod, an expression for the internal pressure of the buffer during landing of a single-chamber landing gear is given. This allows for convenient and quick calculation of the internal pressure of the buffer during aircraft landing, providing input for the strength calculation of internal components of the buffer. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the overall process of this application;

[0043] Figure 2 This is a schematic diagram of the single-chamber landing gear buffer of this application;

[0044] Figure 3 This is a schematic diagram of the forces acting on the piston rod in this application. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0046] The first aspect of this application provides a method for analyzing the internal pressure of a single-chamber landing gear buffer during aircraft landing. The method theoretically analyzes the internal pressure of the buffer during landing of a single-chamber hydropneumatic landing gear, and obtains the pressure expressions for the air chamber and oil chamber of the landing gear buffer of this type of landing gear, providing input for the strength verification of internal components.

[0047] like Figures 1-3 Specifically, it includes the following steps:

[0048] Step S100: Perform a force analysis on the piston rod, ignoring the friction between the piston rod and the plunger, and determine the various loads of the resultant force in the axial direction of the piston rod, including: the load of the gas chamber acting on the piston rod in the circumferential direction, the load of the oil acting on the bottom of the piston rod, and the sum of the load of the gas in the gas chamber acting on the oil needle.

[0049] Preferably, the resultant force along the piston rod in the axial direction can be expressed as:

[0050]

[0051] The resultant force of the piston rod, i.e. the vertical load on the landing gear, is a known parameter;

[0052] The load exerted by the air chamber on the piston rod in the circumferential direction is expressed as:

[0053] .

[0054] in The air chamber pressure, The outer radius of the piston rod. The inner radius of the piston rod;

[0055] The load exerted by the oil on the bottom of the piston rod is expressed as:

[0056] .

[0057] in For oil pressure, The cross-sectional area of ​​the needle oil is related to the compression stroke of the buffer. Related;

[0058] The load exerted by the gas in the gas chamber on the oil needle is expressed as:

[0059] .

[0060] Step S200: Determine the pressure in the gas chamber according to the ideal gas law;

[0061] Preferably, the ideal gas law is: air chamber pressure The expression is:

[0062] ;

[0063] In the formula, The constant represents the air variability index. The initial pressure of the air chamber. This represents the initial volume of the air cavity.

[0064] In step S300, the loads acting on the piston rod circumferentially by the gas chamber, the loads acting on the bottom of the piston rod by the oil, the load of the gas in the gas chamber acting on the oil needle, and the gas chamber pressure are substituted into the piston rod axial resultant force equation to obtain the oil chamber pressure.

[0065] Preferably, the expression for the oil cavity pressure is:

[0066] ;

[0067] In the formula, This represents the component of the vertical ground load on the buffer strut axis during landing.

[0068] As another specific implementation, a system for managing the internal pressure of a single-chamber landing gear buffer during aircraft landing includes:

[0069] The piston rod resultant force calculation module is used to perform force analysis on the piston rod, ignore the friction between the piston rod and the plunger, and determine the resultant force in the axial direction of the piston rod, including: the sum of the load of the gas chamber acting on the piston rod in the circumferential direction, the load of the oil acting on the bottom of the piston rod, and the load of the gas in the gas chamber acting on the oil needle.

[0070] The gas chamber pressure calculation module is used to determine the gas chamber pressure based on the ideal gas law.

[0071] The oil chamber pressure calculation module is used to calculate the circumferential load of the gas chamber on the piston rod and the load of the oil on the bottom of the piston rod. The load of the gas in the gas chamber acting on the oil needle and the gas chamber pressure are substituted into the axial resultant force equation of the piston rod to obtain the oil chamber pressure.

[0072] Preferably, The load exerted by the air chamber on the piston rod in the circumferential direction is expressed as:

[0073] ;

[0074] in The air chamber pressure, The outer radius of the piston rod. Let be the inner radius of the piston rod.

[0075] Preferably, The load exerted by the oil on the bottom of the piston rod is expressed as:

[0076] ;

[0077] in For oil pressure, The cross-sectional area of ​​the needle oil is related to the compression stroke of the buffer. Related.

[0078] Preferably, The load exerted by the gas in the gas chamber on the oil needle is expressed as:

[0079] .

[0080] Preferably, the ideal gas law is: air chamber pressure The expression is:

[0081] ;

[0082] In the formula, The constant represents the air variability index. The initial pressure of the air chamber. This represents the initial volume of the air cavity.

[0083] Preferably, the expression for the oil cavity pressure is:

[0084] ;

[0085] In the formula, This represents the component of the vertical ground load on the buffer strut axis during landing.

[0086] In summary, this application has the following advantages:

[0087] By establishing the axial force balance equation of the buffer piston rod, an expression for the internal pressure of the buffer during landing of a single-chamber landing gear is given. This allows for convenient and quick calculation of the internal pressure of the buffer during aircraft landing, providing input for the strength calculation of internal components of the buffer.

[0088] In a specific instance, the pressure inside the buffer of a single-chamber landing gear of an aircraft during landing is measured. The initial pressure of the air chamber is known. The initial volume of the air chamber is 1.6 MPa. 13,000,000 mm 3 The inner radius of the piston rod is The outer radius of the piston rod is Compression The piston rod axial force is 89mm. 350,000 N, atmospheric variability index Take 1.1, the cross-sectional area of ​​the oil needle is .

[0089] Calculate the air chamber pressure: ;

[0090] Oil chamber pressure: =15.18MPa.

[0091] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing, characterized in that, include: Force analysis is performed on the piston rod, ignoring the friction between the piston rod and the plunger, to determine the various loads of the resultant force in the axial direction of the piston rod, including: the load of the gas chamber acting on the piston rod in the circumferential direction, the load of the oil acting on the bottom of the piston rod, and the sum of the load of the gas in the gas chamber acting on the oil needle. Determine the pressure in the gas chamber based on the ideal gas law; Substituting the loads of the gas chamber acting on the piston rod circumferentially, the loads of the oil acting on the bottom of the piston rod, the loads of the gas in the gas chamber acting on the oil needle, and the gas chamber pressure into the equation of the axial resultant force of the piston rod, the oil chamber pressure is obtained.

2. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 1, characterized in that, The load exerted by the air chamber on the piston rod in the circumferential direction is expressed as: ； in The air chamber pressure, The outer radius of the piston rod. Let be the inner radius of the piston rod.

3. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 2, characterized in that... The load exerted by the oil on the bottom of the piston rod is expressed as: ； in For oil pressure, The cross-sectional area of ​​the needle oil is related to the compression stroke of the damper. Related.

4. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 3, characterized in that, The load exerted by the gas in the gas chamber on the oil needle is expressed as: 。 5. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 4, characterized in that... The ideal gas law is air chamber pressure The expression is: ； In the formula, The constant represents the air variability index. The initial pressure of the air chamber. This represents the initial volume of the air chamber.

6. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 5, characterized in that, The expression for the oil chamber pressure is: ； In the formula, This represents the component of the vertical ground load on the buffer strut axis during landing.

7. A system for managing the internal pressure of a single-chamber landing gear buffer during aircraft landing, comprising the method described in any one of claims 1-6, characterized in that, include: The piston rod resultant force calculation module is used to perform force analysis on the piston rod, ignore the friction between the piston rod and the plunger, and determine the resultant force in the axial direction of the piston rod, including: the sum of the load of the gas chamber acting on the piston rod in the circumferential direction, the load of the oil acting on the bottom of the piston rod, and the load of the gas in the gas chamber acting on the oil needle. The gas chamber pressure calculation module is used to determine the gas chamber pressure based on the ideal gas law. The oil chamber pressure calculation module is used to substitute the loads acting on the piston rod circumferentially by the gas chamber, the loads acting on the bottom of the piston rod by the oil, the loads acting on the oil needle by the gas in the gas chamber, and the gas chamber pressure into the piston rod axial resultant force equation to obtain the oil chamber pressure.

8. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 7, characterized in that, The load exerted by the air chamber on the piston rod in the circumferential direction is expressed as: ； in The air chamber pressure, The outer radius of the piston rod. Let be the inner radius of the piston rod.

9. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 7, characterized in that... The load exerted by the oil on the bottom of the piston rod is expressed as: ； in For oil pressure, The cross-sectional area of ​​the needle oil is related to the compression stroke of the damper. Related.

10. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 7, characterized in that, The load exerted by the gas in the gas chamber on the oil needle is expressed as: 。 11. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 7, characterized in that, The ideal gas law is air chamber pressure The expression is: ； In the formula, The constant represents the air variability index. The initial pressure of the air chamber. This represents the initial volume of the air chamber.

12. The method for controlling the internal pressure of a single-chamber landing gear buffer during aircraft landing as described in claim 7, characterized in that, The expression for the oil chamber pressure is: ； In the formula, This represents the component of the vertical ground load on the buffer strut axis during landing.

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