Method for calculating parameters of linearized model of aircraft landing gear

Abstract

The invention discloses a method for calculating linearization model parameters of an aircraft landing gear. The method comprises the following steps: step 1, obtaining construction parameters of an aircraft landing gear buffer and tires; step 2, according to the obtained construction parameters of the aircraft landing gear buffer and the tires, constructing a linearized simplified model rigidity and damping calculation model, including: calculating and considering the aircraft landing gear buffer principle linearized equivalent buffer rigidity; linear equivalent buffer damping considering the aircraft landing gear buffer principle is calculated; linear equivalent tire rigidity is calculated; linear equivalent tire damping is calculated; and step 3, calculating different aircraft landing gears to obtain calculation results of the different aircraft landing gears. According to the method, unknown rigidity and damping parameters in the linear model of the aircraft landing gear can be scientifically and accurately calculated; for the dynamic characteristics of the bridge structure under the complex aircraft load, the method greatly improves the calculation efficiency compared with refined numerical simulation while ensuring the precision of the calculation result.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge engineering, is used for dynamic performance analysis of aircraft load bridges, including taxiway bridges and runway bridges, and relates to a method for calculating parameters of a linearized model of an aircraft landing gear based on the energy equivalent principle. Background Art

[0002] With the continuous growth of civil aviation transportation and general aviation demand in my country, the number of airports continues to increase, and the number of airport expansion and new construction projects is also gradually increasing. While facing huge construction needs, airports are also facing new situations: on the one hand, due to the restrictions of existing infrastructure and construction land in the surrounding area, new runways or taxiways need to consider the intersection with existing or planned road and rail networks, rivers, pipelines, etc.; on the other hand, due to the restrictions of mountainous and coastal terrain, traditional high fill and reclamation methods have problems such as large engineering volume and environmental damage. The use of taxiway bridges and runway bridges is a good solution to the above problems. The calculation and evaluation of the dynamic performance of taxiway bridges and runway bridges is crucial, but the aircraft load is 8 to 30 times that of a standard vehicle load, and the load distribution range is small.

[0003] For the numerical simulation of aircraft loads, Ling Daosheng et al. proposed a semi-analytical finite element method suitable for the dynamic response analysis of mountain airport runways under aircraft moving loads, derived the corresponding finite element formulas, compiled a finite element analysis program, and verified the correctness of the calculation method and program through examples. Li Yue et al. simulated the aircraft wheel load moving cyclic loading process through a semi-sine waveform loading curve. Guo Chengchao et al. set a moving belt in the Abaqus model to limit the load movement range, and used Fortran language to write the code, considering loads such as vertical pressure and horizontal shear force, so as to realize the aircraft moving load loading. Qi Chunxiang, Liu Li, and Dong Qian all simplified the aircraft into a plane model with 4 degrees of freedom for finite element analysis, namely the vertical movement and longitudinal pitch rotation of the fuselage, the vertical movement of the front landing gear, and the vertical movement of the main landing gear. With the development of numerical simulation technology, Meng Xianfeng, Raju et al. used ADAMS / VI-Aircraft software to establish a refined three-dimensional numerical simulation model of the aircraft. Although accurate aircraft models can help reflect the vibration response information of aircraft components and have broad prospects in aircraft safety analysis, comfort analysis, etc., they are difficult to model and require a lot of calculations, making them unsuitable for bridge impact coefficient research.

[0004] From the above analysis, we can see that many scholars have achieved remarkable results in the areas of aircraft power issues and landing gear design improvements. However, the aircraft models currently used in related research are simplified plane models that do not consider the dynamic characteristics of the aircraft buffer, or are refined models with large computational complexity. Simplified aircraft dynamic analysis models that consider the principles of landing gear buffers are very rare, so further research is needed.

[0005] Aircraft landing gear buffers play an important role in buffering and shock absorption during aircraft landing and taxiing. Traditional buffer design and analysis methods usually use nonlinear analysis techniques to determine their stiffness, damping characteristics and structural response. However, the nonlinear model calculation is complex and requires a large amount of experimental data, which brings difficulties to the design and optimization process. Therefore, it is particularly important to consider the buffer principle to determine the stiffness and damping parameters for the existing simplified and efficient linear model. The parameters should be able to meet the fast calculation of the stiffness and damping of the simplified dynamic model of different types of aircraft while ensuring accuracy, and then it can be used for the dynamic analysis of aircraft-loaded bridges and provide guidance for the study of the dynamic characteristics of aircraft-bridge interaction. Summary of the invention

[0006] The purpose of the present invention is to provide a method for calculating the parameters of a linearized model of an aircraft landing gear, which solves the problem that the simplified aircraft model in the prior art does not fully consider the principle of the landing gear buffer, resulting in a lack of scientific connection between the model and the landing gear structural parameters.

[0007] In order to realize the above technical solutions adopted by the present invention,

[0008] In a first aspect, the present invention provides a method for calculating parameters of a linearized model of an aircraft landing gear, which specifically comprises the following steps:

[0009] Step 1: Obtain the structural parameters of the aircraft landing gear buffer and tire, including: initial pressure P0, buffer effective cross-sectional area A s , the initial volume of the low pressure chamber V l0 、The initial volume of the high pressure chamber V h0 , oil density ρ, buffer effective oil pressure area A h , Damping hole flow coefficient C d , Main oil hole area A d , Oil return hole area A r , Tire elastic modulus E t , tire vertical width B, tire diameter D, tire vertical deformation δ t , tire material density ρ t and tire thickness h t ;

[0010] Step 2, constructing a linear simplified model stiffness and damping calculation model based on the structural parameters of the aircraft landing gear buffer and tire obtained in step 1, including:

[0011] (1) Calculate the equivalent buffer stiffness considering the linearization principle of the aircraft landing gear buffer:

[0012]

[0013] Where γ is the polytropic process index; P0 is the initial pressure of the high-pressure chamber and the low-pressure chamber; A s is the effective cross-sectional area of ​​the buffer; V l0 is the initial volume of the low-pressure chamber; V h0 is the initial volume of the high pressure chamber.

[0014] (2) Calculate the equivalent buffer damping considering the linearization principle of the aircraft landing gear buffer:

[0015]

[0016] Where, ρ is the oil density; A h C is the effective oil pressure area of ​​the buffer; d is the flow coefficient of the damping hole; A d A is the main oil hole area; r is the oil return hole area.

[0017] (3) Calculate the linearized equivalent tire stiffness:

[0018]

[0019] Among them, E t is the elastic modulus of the tire; B is the vertical width of the tire; δ t is the vertical deformation of the tire; D is the tire diameter.

[0020] (4) Calculate the linearized equivalent tire damping:

[0021]

[0022] Where ξ is the damping ratio of the tire material and structure; ρ t is the density of the tire material; h t is the tire thickness;

[0023] Step 3, according to the linear simplified model stiffness and damping calculation model constructed in step 2, different aircraft landing gears are calculated to obtain calculation results of different aircraft landing gears.

[0024] Furthermore, the effective cross-sectional area A of the buffer s Measured by laser ranging;

[0025] The initial volume V of the low pressure chamber l0 and the initial volume V of the high pressure chamber h0 All were measured by water displacement method;

[0026] The vertical deformation of the tire δ t Measured using a displacement sensor or laser distance meter under static or dynamic load.

[0027] Furthermore, the polytropic process index γ is 1.4.

[0028] Furthermore, the damping ratio ξ of the tire material and structure is 0.1 to 0.3.

[0029] In a second aspect, the present invention provides a device for calculating parameters of a linearized model of an aircraft landing gear, comprising the following modules:

[0030] Aircraft landing gear buffer and tire structural parameter acquisition module, used to obtain the structural parameters of the aircraft landing gear buffer and tire, including: initial pressure P0, buffer effective cross-sectional area A s , the initial volume of the low pressure chamber V l0 、The initial volume of the high pressure chamber V h0 , oil density ρ, buffer effective oil pressure area A h , Damping hole flow coefficient C d , Main oil hole area A d , Oil return hole area A r , Tire elastic modulus E t , tire vertical width B, tire diameter D, tire vertical deformation δ t , tire material density ρ t and tire thickness h t ;

[0031] The calculation model construction module is used to construct a linear simplified model stiffness and damping calculation model according to the aircraft landing gear buffer and tire structural parameters obtained by the aircraft landing gear buffer and tire structural parameter acquisition module, including:

[0032] (1) Calculate the equivalent buffer stiffness considering the linearization principle of the aircraft landing gear buffer:

[0033]

[0034] Where γ is the polytropic process index; P0 is the initial pressure of the high-pressure chamber and the low-pressure chamber; A s is the effective cross-sectional area of ​​the buffer; V l0 is the initial volume of the low-pressure chamber; V h0 is the initial volume of the high pressure chamber.

[0035] (2) Calculate the equivalent buffer damping considering the linearization principle of the aircraft landing gear buffer:

[0036]

[0037] Where, ρ is the oil density; A h C is the effective oil pressure area of ​​the buffer; d is the flow coefficient of the damping hole; A d A is the main oil hole area; ris the oil return hole area.

[0038] (3) Calculate the linearized equivalent tire stiffness:

[0039]

[0040] Among them, E t is the elastic modulus of the tire; B is the vertical width of the tire; δ t is the vertical deformation of the tire; D is the tire diameter.

[0041] (4) Calculate the linearized equivalent tire damping:

[0042]

[0043] Where ξ is the damping ratio of the tire material and structure; ρ t is the density of the tire material; h t is the tire thickness;

[0044] The calculation module calculates different aircraft landing gears according to the linearized simplified model stiffness and damping calculation model constructed by the calculation model construction module, and obtains calculation results of different aircraft landing gears.

[0045] In a third aspect, the present invention provides an electronic device, the electronic device comprising:

[0046] A memory for storing executable instructions;

[0047] The processor is used to implement the method for calculating the linearization model parameters of the aircraft landing gear provided by the first aspect of the present invention when executing the executable instructions or computer programs stored in the memory.

[0048] In a fourth aspect, the present invention provides a computer-readable storage medium storing executable instructions or a computer program, characterized in that when the executable instructions are executed by a processor, the method for calculating the linearization model parameters of the aircraft landing gear provided in the first aspect of the present invention is implemented.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] The method of the present invention establishes the relationship between the aircraft linear model considering the landing gear buffer principle and the internal structural parameters of the landing gear based on the energy equivalence principle, and provides a scientific calculation method for the unknown stiffness and damping parameters of the existing aircraft landing gear linearization model. Through this method, the unknown stiffness and damping parameters in the existing aircraft landing gear linearization model can be calculated scientifically and accurately; for the dynamic characteristics of the bridge structure under complex aircraft loads, this method greatly improves the calculation efficiency compared to the refined numerical simulation while ensuring the accuracy of the calculation results. A scientific connection is established between the unknown stiffness and damping values ​​of the existing aircraft simplified model and the landing gear structural parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a simplified diagram of an aircraft landing gear model.

[0052] The technical solution of the present invention is further explained below in conjunction with the accompanying drawings and specific implementation methods. DETAILED DESCRIPTION

[0053] like Figure 1 As shown, the calculation method of the aircraft landing gear linearization model parameters provided by the present invention specifically includes the following steps:

[0054] Step 1: Obtain the structural parameters of the aircraft landing gear buffer and tire, including: initial pressure P0, buffer effective cross-sectional area A s , the initial volume of the low pressure chamber V l0 、The initial volume of the high pressure chamber V h0 , oil density ρ, buffer effective oil pressure area A h , Damping hole flow coefficient C d , Main oil hole area A d , Oil return hole area A r , Tire elastic modulus E t , tire vertical width B, tire diameter D, tire vertical deformation δ t , tire material density ρ t and tire thickness h t .

[0055] The specific ways to obtain these parameters are as follows:

[0056] (1) Initial pressure P0: Many landing gear buffer designs reserve pressure measuring ports on the high-pressure chamber and the low-pressure chamber. These pressure measuring ports are generally located on the outer shell of the buffer for easy installation. Through these pressure measuring ports, the pressure sensor can be directly connected to the inside of the cavity to monitor the initial pressure of the high-pressure chamber and the low-pressure chamber in real time. If there are no dedicated pressure measuring ports, holes can be drilled on the outer shell of the high-pressure chamber and the low-pressure chamber to install the pressure sensor. This installation method requires ensuring that the sensor is in contact with the gas or liquid inside the cavity and maintains good sealing to prevent leakage.

[0057] (2) Buffer effective cross-sectional area A s : Calculation through geometric design of the buffer or measurement using a measuring instrument (such as a laser rangefinder) are both common methods in this field.

[0058] (3) Initial volume V l0 and V h0 : Calculation based on the design drawings of the buffer, or direct measurement by water displacement method, are both commonly used methods in this field.

[0059] (4) Oil density ρ: Use a densitometer to measure the oil density under standard conditions. The densitometer can be installed in the oil pipe or oil circuit system connected to the oil storage chamber of the oil buffer, so as to ensure that the densitometer can contact the oil in the buffer in real time during operation. If the system allows, the densitometer can be installed on a bypass pipe, and a part of the oil is introduced into the bypass through the control valve for density measurement, so as not to affect the normal operation of the buffer. For some oil buffers with more complex designs, it is possible to consider reserving a density measurement cavity inside the buffer and using a built-in densitometer for real-time measurement.

[0060] (5) Buffer effective oil pressure area A h : Obtained through conventional calculations combining the structural characteristics and geometry of the buffer.

[0061] (6) Damping hole flow coefficient C d :Measured by fluid dynamics experiments, the flow rate through the damping orifice is recorded using a flow meter. The flow meter can be installed on the inlet or outlet oil pipe of the damping orifice to directly measure the fluid flow through the damping orifice. This installation method can accurately capture the changes in flow rate, especially the instantaneous flow rate when the oil passes through the damping orifice. If the buffer has a dedicated return oil line, the flow meter can be installed here, because the flow rate of the return oil pipe is usually equal to the flow rate through the damping orifice. This can avoid installing the flow meter directly in the high-pressure area, improving the simplicity and safety of installation.

[0062] (7) Main oil hole and oil return hole area A d and A r: Calculation based on the pore size and number, or measurement of the geometric parameters of the pores using a microscope are both commonly used methods in this field.

[0063] (8) Tire elastic modulus E t : It can be obtained by material testing, such as using a tensile testing machine to measure the elastic modulus of the tire material.

[0064] (9) Tire vertical width B and diameter D: Measure the tire size directly using precision measuring tools such as calipers.

[0065] (10) Tire vertical deformation δ t : Measure the deformation of the tire under static or dynamic load, using displacement sensors or laser rangefinders.

[0066] (11) Density of tire material ρ t and thickness h t : The density of the tire material is determined by sampling and experiment, and the thickness of the tire is directly measured using a vernier caliper.

[0067] Step 2, constructing a linear simplified model stiffness and damping calculation model based on the structural parameters of the aircraft landing gear buffer and tire obtained in step 1, including:

[0068] (1) Calculate the equivalent buffer stiffness considering the linearization principle of the aircraft landing gear buffer:

[0069]

[0070] Among them, γ is the polytropic process index, and the adiabatic process γ = 1.4; P0 is the initial pressure of the high-pressure chamber and the low-pressure chamber. In the initial reference state of the air spring (i.e., static equilibrium state), the initial pressures of the high-pressure chamber and the low-pressure chamber are equal. Because in the static state where the system is not subjected to external loads and no displacement or compression occurs, the two chambers are in equilibrium. ; A s is the effective cross-sectional area of ​​the buffer; V l0 is the initial volume of the low-pressure chamber; V h0 is the initial volume of the high pressure chamber.

[0071] (2) Calculate the equivalent buffer damping considering the linearization principle of the aircraft landing gear buffer:

[0072]

[0073] Where, ρ is the oil density; A h C is the effective oil pressure area of ​​the buffer; d is the flow coefficient of the damping hole; A d A is the main oil hole area; r is the oil return hole area.

[0074] (3) Calculate the linearized equivalent tire stiffness:

[0075]

[0076] Among them, E t is the elastic modulus of the tire; B is the vertical width of the tire; δ t is the vertical deformation of the tire; D is the tire diameter.

[0077] (4) Calculate the linearized equivalent tire damping:

[0078]

[0079] Where ξ is the damping ratio of the tire material and structure, which is generally 0.1 to 0.3; ρ t is the density of the tire material; h t is the tire thickness.

[0080] The calculation formulas in the above linear simplified model stiffness and damping calculation model are obtained based on the following analysis:

[0081] 1. Construction of nonlinear model and calculation of air spring stiffness:

[0082] (1) For the aircraft landing gear structure, the buffer force can be divided into the air spring force F as and oil damping force F d Two parts, namely: F ci =F as +F d

[0083] (2) The air spring force F mentioned in (1) as It can be calculated by the following formula:

[0084] Where P0 is the initial pressure of the high-pressure chamber and the low-pressure chamber; V l0 is the initial volume of the low-pressure chamber; V h0 is the initial volume of the high pressure chamber; A s is the effective cross-sectional area of ​​the buffer; γ is the polytropic process index, and for the adiabatic process γ=1.4.

[0085] (3) Nonlinear stiffness k of the air spring in the buffer as is the air spring force F as The displacement y of the buffer relative to the fuselage i -y M The first-order derivative of is expressed as

[0086]

[0087] 2. Linearization process of air spring stiffness based on energy equivalence principle:

[0088] (4) Use mathematical analysis to linearize the complex nonlinear equation. According to the energy equivalence principle, the linearized spring stiffness k as,linear and nonlinear air spring stiffness have the same elastic energy at the same displacement amplitude.

[0089] (5) The air spring force F mentioned in (1) above as The nonlinear elastic energy generated is

[0090]

[0091] (6) Stiffness k after linearization as,linear The elastic energy generated is

[0092]

[0093] (7) According to the energy equivalence principle described in (4), (5) and (6) are equal, that is, E linear =E nonlinear For the convenience of calculation, let Δy = y i -y M , and replace F in (2) as Substituting the expression of into (5), we get the following formula:

[0094]

[0095] (8) According to the Tylor expansion in mathematical methods, the nonlinear F as After linearization, we have the following formula:

[0096] Under the initial static equilibrium condition, F in the above formula as (0) = 0

[0097] So there is F as It can be approximated by the linear stiffness and displacement y of the buffer relative to the fuselage i -y M The product of

[0098]

[0099] (9) The linear stiffness k can be inversely calculated from the last equation in (8): as,linear for:

[0100]

[0101] (10) Replace (2) with F as Substituting the expression into (9) we can get:

[0102] Combining similar terms, the air spring stiffness can be calculated according to the following formula:

[0103]

[0104] Among them, k ci is the linearized stiffness considering the buffer principle, that is, the linearized stiffness considering the influence of oil and gas inside the buffer. i is n / r / l, which are the front landing gear, left main landing gear and right main landing gear respectively.

[0105] 3. Calculation of buffer oil damping

[0106] (11) The oil damping force F mentioned in (1) d Establishing a connection with the buffer's own structural parameters, this formula can be used to calculate:

[0107]

[0108] Where ΔP is the pressure difference; A h is the effective oil pressure area of ​​the buffer; ρ is the oil density; v p Positive stroke speed; v r A is the reverse stroke speed; d A is the main oil hole area; r is the oil return hole area.

[0109] (12) According to the basic mechanics of landing gear buffer, the actual flow rate of oil

[0110] (13) Oil damping force F d It can also be expressed as: F d =c d v oil 2 .

[0111] 4. Oil damping linearization based on RMS method

[0112] (14) The nonlinear damping force in (13) is equivalently linearized using another mathematical method other than the equivalent capacity principle, namely the root mean square (RMS) value, which can be expressed as:

[0113]

[0114] (15) Assuming the oil flow rate v oil The average value over a period of time is but

[0115]

[0116] (16) According to the RMS value principle mentioned in (14), there exists an equivalent linear damping coefficient c d,eq Make the RMS value of the linear system equal to the RMS value of the nonlinear system.

[0117] (17) According to (16), the equivalent linear system F d,eq =c d,eq v oil , the RMS value of the system is:

[0118] (18) According to the principle of equal RMS value,

[0119]

[0120] (19) According to (18), the equivalent damping can be expressed as

[0121]

[0122] (20) Substitute the equivalent damping obtained in (19) into the solution of the equivalent oil damping force,

[0123] (21) The oil damping force can be approximately equal to the product of the equivalent damping and the oil flow rate, that is,

[0124]

[0125] (22) According to (21), and considering the relationship between the construction parameters and the oil damping force in (11), it can be obtained:

[0126]

[0127] (23) According to (22), the linear damping considering the buffer principle can be solved as:

[0128]

[0129] 5. Establishment of landing gear tire mechanical relationship and calculation and linearization of tire stiffness and damping

[0130] (24) A similar method is used to obtain the linear stiffness and damping of the above buffer to establish the relationship between the tire force stiffness and damping and its internal structural parameters. Assuming that the tire is a torus, its relevant parameters are: mass m t , diameter D, width B, vertical stiffness k ti (i is n / r / l), vertical damping c ti , vertical deformation δ t , deformation speed Elastic modulus E t, ground contact area A t , ground length l t .

[0131] Similarly, the stiffness and damping of the tire can also be linearized. The detailed process will not be repeated here. Finally, we can get:

[0132]

[0133] (25)The damping of the tire can be expressed as:

[0134]

[0135] Where ξ is the damping ratio of the tire material and structure, which is generally between 0.1 and 0.3. t =ρ t V t

[0136] Among them, ρ t is the density of the tire material, V t is the volume of the tire. For a simplified model, the tire is approximated as a hollow ring. Among them, h t is the tire thickness;

[0137] Put k in (24) ti and m t Substituting the calculation formula into the initial tire stiffness damping expression, we can get:

[0138]

[0139] 6. Aircraft landing gear buffer and tire linear model integration

[0140] (26) (10), (23), (24) and the last equation in (25) can form the mathematical relationship between stiffness, damping and basic structural parameters of the landing gear in the mathematically simplified mass-stiffness-damping model of the landing gear considering the buffer principle. It can be used for different types of aircraft landing gear systems and to simplify their dynamic performance, and then the simplified model can be used for the dynamic characteristics analysis and evaluation of aircraft load bridges.

[0141] Step 3, according to the linear simplified model stiffness and damping calculation model constructed in step 2, different aircraft landing gears are calculated to obtain calculation results of different aircraft landing gears.

[0142] The results obtained in this step can be used for subsequent dynamic analysis of the bridge under aircraft loads.

[0143] From the above, the method of the present invention linearizes the air spring stiffness and damping by using energy equivalent distance. This solution overcomes the following difficulties:

[0144] ① Complexity of nonlinear elastic characteristics: The nonlinear stiffness characteristics of landing gear air springs are susceptible to multiple effects of compression, temperature and gas state, and to convert them into linear stiffness parameters, it is necessary to overcome their complex nonlinear constitutive relations. Since the nonlinear characteristics of air springs fluctuate significantly with changes in pressure and volume, it is difficult to meet the accuracy requirements only through simplified mechanical relationships.

[0145] ② Difficulty in applying the energy equivalence principle: The application of the energy equivalence principle is usually used in simple mechanical systems, while the energy absorption process of air springs involves the dynamic process of gas expansion and compression, which requires accurate modeling of energy changes under different working conditions. In addition, in order to achieve linearization, the energy absorption characteristics of the nonlinear system need to be equivalent to a single linear stiffness coefficient. This conversion process involves complex integration and approximation methods, which is extremely challenging. The stiffness and damping parameters determined by the method of the present invention can meet the rapid calculation of stiffness and damping of simplified dynamic models of different types of aircraft while ensuring accuracy. It can then be used for the dynamic analysis of aircraft-loaded bridges and provide guidance for the study of the dynamic characteristics of aircraft-bridge interactions. Its application in the dynamic analysis of aircraft-loaded bridges is as follows:

[0146] ① Establish a mass-spring-damper model: Use linearized stiffness and damping parameters to construct a simplified aircraft model, and use a mass-spring-damper system to represent the dynamic characteristics of the aircraft during taxiing.

[0147] This model is used to simulate the moving loads and damping effects of an aircraft.

[0148] ②Construct a bridge-aircraft coupling system: Combine the finite element model of the aircraft bridge with the simplified aircraft model to form a coupling system. The bridge model should include the structural units of the bridge and the supporting boundary conditions to accurately reflect the mechanical properties of the bridge.

[0149] ③ Apply taxiing load: Apply dynamic loads based on the aircraft taxiing speed, direction and load in the simulation. Through linearized stiffness and damping parameters, control the transmission mode of impact force during aircraft taxiing and simulate the actual dynamic effect of landing gear on the bridge.

[0150] ④ Calculate the dynamic response of the aircraft bridge: Perform time history analysis to calculate the stress, deformation and vibration response of the bridge under different taxiing speeds and aircraft weight conditions, and evaluate the dynamic performance of the bridge.

Claims

1. A method for calculating the parameters of a linearized model of an aircraft landing gear, characterized in that (This sentence is a summary and cannot be placed in the claims, but can be placed in the specification), specifically including the following steps: Step 1: Obtain the structural parameters of the aircraft landing gear buffer and tire, including: initial pressure P0, buffer effective cross-sectional area A s , the initial volume of the low pressure chamber V l0 、The initial volume of the high pressure chamber V h0 , oil density ρ, buffer effective oil pressure area A h , Damping hole flow coefficient C d , Main oil hole area A d , Oil return hole area A r , Tire elastic modulus E t , tire vertical width B, tire diameter D, tire vertical deformation δ t , tire material density ρ t and tire thickness h t ; Step 2, constructing a linear simplified model stiffness and damping calculation model based on the structural parameters of the aircraft landing gear buffer and tire obtained in step 1, including: (1) Calculate the equivalent buffer stiffness considering the linearization principle of the aircraft landing gear buffer: Where γ is the polytropic process index; P0 is the initial pressure of the high-pressure chamber and the low-pressure chamber; A s is the effective cross-sectional area of ​​the buffer; V l0 is the initial volume of the low-pressure chamber; V h0 is the initial volume of the high pressure chamber. (2) Calculate the equivalent buffer damping considering the linearization principle of the aircraft landing gear buffer: Where, ρ is the oil density; A h C is the effective oil pressure area of ​​the buffer; d is the flow coefficient of the damping hole; A d A is the main oil hole area; r is the oil return hole area. (3) Calculate the linearized equivalent tire stiffness: Among them, E t is the elastic modulus of the tire; B is the vertical width of the tire; δ t is the vertical deformation of the tire; D is the tire diameter. (4) Calculate the linearized equivalent tire damping: Where ξ is the damping ratio of the tire material and structure; ρ t is the density of the tire material; h t is the tire thickness; Step 3, according to the linear simplified model stiffness and damping calculation model constructed in step 2, different aircraft landing gears are calculated to obtain calculation results of different aircraft landing gears.

2. The method for calculating the parameters of the linearized model of an aircraft landing gear according to claim 1, characterized in that: The effective cross-sectional area of ​​the buffer A s Measured by laser ranging; The initial volume V of the low pressure chamber l0 and the initial volume V of the high pressure chamber h0 All were measured by water displacement method; The vertical deformation of the tire δ t Measured using a displacement sensor or laser distance meter under static or dynamic load.

3. The method for calculating the parameters of the linearized model of an aircraft landing gear according to claim 1, characterized in that: The polytropic process index γ is 1.

4.

4. The method for calculating the parameters of the linearized model of an aircraft landing gear according to claim 1, characterized in that: The damping ratio ξ of the tire material and structure is 0.1 to 0.

3.

5. A device for calculating parameters of a linearized model of an aircraft landing gear, characterized in that: Includes the following modules: Aircraft landing gear buffer and tire structural parameter acquisition module, used to obtain the structural parameters of the aircraft landing gear buffer and tire, including: initial pressure P0, buffer effective cross-sectional area A s , the initial volume of the low pressure chamber V l0 、The initial volume of the high pressure chamber V h0 , oil density ρ, buffer effective oil pressure area A h , Damping hole flow coefficient C d , Main oil hole area A d , Oil return hole area A r , Tire elastic modulus E t , tire vertical width B, tire diameter D, tire vertical deformation δ t , tire material density ρ t and tire thickness h t ; The calculation model construction module is used to construct a linear simplified model stiffness and damping calculation model according to the aircraft landing gear buffer and tire structural parameters obtained by the aircraft landing gear buffer and tire structural parameter acquisition module, including: (1) Calculate the equivalent buffer stiffness considering the linearization principle of the aircraft landing gear buffer: Where γ is the polytropic process index; P0 is the initial pressure of the high-pressure chamber and the low-pressure chamber; A s is the effective cross-sectional area of ​​the buffer; V l0 is the initial volume of the low-pressure chamber; V h0 is the initial volume of the high pressure chamber. (2) Calculate the equivalent buffer damping considering the linearization principle of the aircraft landing gear buffer: Where, ρ is the oil density; A h C is the effective oil pressure area of ​​the buffer; d is the flow coefficient of the damping hole; A d A is the main oil hole area; r is the oil return hole area; (3) Calculate the linearized equivalent tire stiffness: Among them, E t is the elastic modulus of the tire; B is the vertical width of the tire; δ t is the vertical deformation of the tire; D is the tire diameter; (4) Calculate the linearized equivalent tire damping: Where ξ is the damping ratio of the tire material and structure; ρ t is the density of the tire material; h t is the tire thickness; The calculation module calculates different aircraft landing gears according to the linearized simplified model stiffness and damping calculation model constructed by the calculation model construction module, and obtains calculation results of different aircraft landing gears.

6. An electronic device, characterized in that: The electronic device comprises: A memory for storing executable instructions; a processor for executing the executable instructions or computer programs stored in the memory to implement the method according to any one of claims 1 to 4.

7. A computer-readable storage medium storing executable instructions or a computer program, characterized in that: When the executable instructions are executed by a processor, the method according to any one of claims 1 to 4 is implemented.

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