Finite element modeling method for aircraft landing gear impact response

Abstract

The application belongs to the technical field of aircraft take-off and landing impact response analysis, and particularly relates to a finite element modeling method for aircraft take-off and landing impact response, which reduces modeling difficulty and modeling time through a modular feasible and rapid simplification method, can rapidly establish a finite element model for aircraft take-off and landing impact, adopts a reasonable simplification method to control key parameters, can avoid solver error caused by unreasonable element types, ensures the accuracy of simulation results, and in addition, the obtained finite element modeling is relatively simplified, can improve the speed of simulation calculation, and can meet the needs of engineering design in modeling efficiency, calculation efficiency and calculation accuracy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft take-off and landing impact response analysis, and particularly relates to a finite element modeling method for aircraft take-off and landing impact response. BACKGROUND

[0002] The aircraft lands on the ship and takes off, which will generate a large load impact in a short time, and may cause damage to the aircraft structure, seriously threatening the flight safety of the aircraft, and is an important working condition for aircraft strength analysis. At the same time, the dynamic response of each part of the aircraft body during the take-off and landing process is also a typical environment that needs to be covered in the mechanical environment test.

[0003] At present, the impact dynamics response simulation of the aircraft take-off and landing process mainly adopts an explicit dynamics simulation method. The explicit dynamics simulation method has great advantages in the simulation of large displacement, large rotation, structure collision, nonlinear oil damping simulation, etc. in the dynamic response calculation, but the pre-processing function of the finite element is not perfect, and there is no finite element rapid modeling method for the aircraft take-off and landing impact response.

[0004] The present application is proposed in view of the existence of the above technical defects. SUMMARY

[0005] The purpose of the present application is to provide a finite element modeling method for aircraft take-off and landing impact response, which quickly establishes an explicit dynamics finite element model by a modular simplification method, and provides an accurate analysis of the full aircraft arresting impact dynamics response.

[0006] The technical solution of the present application is:

[0007] A finite element modeling method for aircraft take-off and landing impact response, comprising:

[0008] Step one, using the existing full aircraft finite element model for the fuselage, wings and tail;

[0009] Step two, simplifying the modeling of the landing gear, retaining the buffer inner cylinder, outer cylinder, torsion arm, tire, strut, connection between the tire and the buffer, spring element simulating the tire characteristics, kinematic pair between the inner and outer cylinders, damping element and spring element between the inner and outer cylinders, and front traction rod and rear restraint rod on the front landing gear;

[0010] The buffer inner cylinder and outer cylinder use rigid plate shell elements, the torsion arm and strut use rigid beam elements, and the tire uses rigid body elements to simulate the shape;

[0011] The piston movement between the buffer inner cylinder and outer cylinder is realized by defining the kinematic pair, and the damping element and spring element in the piston movement direction between the inner and outer cylinders are used to simulate the energy absorption and energy dissipation performance of the buffer;

[0012] Spring elements are arranged between the tire and the bumper to simulate the mechanical properties of the tire;

[0013] The rear drag link uses a breakable connection unit to simulate the breaking situation according to a set breaking criterion;

[0014] Step three, simplify the model of the arresting gear hook, and keep the hook body, the roll-damping and retractable actuator, the hook head, the body hinge shaft, the arresting gear hook hinge shaft, and the lateral stabilizer;

[0015] The hook body and the hook head are simulated by rigid body elements;

[0016] The roll-damping and retractable actuator and the lateral stabilizer are simulated by damping elements;

[0017] The body hinge shaft and the arresting gear hook hinge shaft are simulated by kinematic pairs;

[0018] Step four, simplify the model of the arresting gear rope, and keep the first belt element and the second belt element;

[0019] The common node at the inner end of the first belt element and the second belt element is connected to the node on the hook head in the longitudinal symmetry plane of the arresting gear hook model;

[0020] The first node and the second node at the outer end of the first belt element and the second belt element are constrained;

[0021] Step five, simplify the model of the take-off booster, control the movement of the node of the front drag link on the catapult track by defining the forced velocity in the vertical and lateral directions as zero, and define the velocity curve in the heading direction;

[0022] A concentrated mass element is defined at the node of the front drag link on the catapult track to simulate the slider;

[0023] The catapult traction force in the heading direction is applied at the node of the front drag link on the catapult track;

[0024] Step six, simplify the model of the runway surface, simulate the runway surface with quadrilateral plate shell mesh, define the runway surface as a rigid body, and define the rigid body constraint as completely fixed;

[0025] Define the contact between the tire and the runway surface, with the runway surface as the main surface.

[0026] Optionally, in the finite element modeling method for the aircraft take-off and landing impact response described above, in step two, the damping elements and the spring elements are defined and simulated by imported curves to simulate the energy absorption and dissipation performance of the bumper.

[0027] Optionally, in the finite element modeling method for aircraft take-off and landing impact response, in step two, the spring element is defined by importing a curve to simulate the mechanical properties of the tire.

[0028] Optionally, in the finite element modeling method for aircraft take-off and landing impact response, in step three, the damping element of the anti-sway-retractable actuator and the lateral stabilizer is set by importing a curve to define the specific performance parameters.

[0029] Optionally, in the finite element modeling method for aircraft take-off and landing impact response, in step four, the force-displacement relationship of the lateral belt element is obtained according to the actual longitudinal drag force and the angle geometric parameters of the lateral arresting device rope, and the properties of the first belt element and the second belt element are defined.

[0030] The present application has at least the following beneficial technical effects:

[0031] The present application provides a finite element modeling method for aircraft take-off and landing impact response, which reduces the modeling difficulty and modeling time through a modularized feasible and rapid simplification method, can quickly establish a finite element model for aircraft take-off and landing impact, controls key parameters using a reasonable simplification method, avoids solver errors caused by unreasonable element types, ensures the accuracy of simulation results, and further simplifies the obtained finite element modeling, improves the speed of simulation calculation, and meets the needs of engineering design in modeling efficiency, calculation efficiency and calculation accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic diagram of the finite element modeling method for aircraft take-off and landing impact response provided by the present application;

[0033] Figure 2 is a schematic diagram of the simplified modeling of the landing gear provided by the present application;

[0034] Figure 3 is a schematic diagram of the simplified modeling of the arresting device hook provided by the present application;

[0035] Figure 4 is a schematic diagram of the simplified modeling of the arresting device rope provided by the present application;

[0036] Figure 5 is a schematic diagram of the simplified modeling of the take-off assist device provided by the present application.

[0037] In order to better illustrate the present application, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product. In addition, the drawings are only used for illustrative purposes and cannot be understood as limiting the present application. DETAILED DESCRIPTION

[0038] In order to make the technical solutions of the present application and its advantages clearer, the technical solutions of the present application will be further clearly and completely described in detail below in combination with the drawings. It should be understood that the specific embodiments described herein are only part of the embodiments of the present application, which are only used to explain the present application, but not to limit the present application. It should be noted that, for the convenience of description, only parts related to the present application are shown in the drawings, and other related parts can be referred to the general design.

[0039] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present application should be the general meanings understood by the general skilled person in the field to which the present application belongs. The words indicating the position used in the description of the present application are only used to indicate the relative direction or positional relationship, and the relative positional relationship may also change accordingly when the absolute position of the described object changes. The "comprising" used in the description of the present application indicates that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, and other elements or objects are not excluded.

[0040] In addition, it should be further noted that, unless otherwise explicitly specified and limited, the "installation", "connection" and similar words used in the description of the present application should be understood in a broad sense, for example, the connection can be fixed connection, or detachable connection; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium, the skilled person in the art can understand the specific meaning of the present application according to the specific circumstances.

[0041] Before establishing the finite element model of the missile impact response of the aircraft, there is generally a full aircraft finite element model for static analysis or other dynamic analysis. The finite element model of the missile impact response of the aircraft is established on the basis of the existing full aircraft model, which can save a lot of manpower and time. However, the following key technical problems need to be solved:

[0042] First, the simplification method of the landing gear, how to retain the core parameters;

[0043] Second, the simplified modeling method of the arrestor hook;

[0044] Third, the simplified modeling method of the arrestor cable;

[0045] Fourth, the simplified modeling method of the take-off booster.

[0046] After the landing gear, the arrestor hook, the arrestor cable and the take-off booster are simplified, the simulation accuracy of physical quantities such as displacement, acceleration, stress and strain on the aircraft body should be ensured. For this purpose, the present application provides a finite element modeling method for the take-off and landing impact response of an aircraft, comprising the following steps.

[0047] Step one, the fuselage, wings, tail and other body structure, using the existing full machine finite element model.

[0048] Step two, the landing gear for simplified modeling.

[0049] According to the purpose of simulation analysis, the landing gear part focuses on the mechanical properties of the oil and gas buffer, the drag bar and the tire, and after simplified modeling, only the position information and key mechanical properties are retained.

[0050] The main structures retained for the landing gear modeling are the buffer inner cylinder 1, the buffer outer cylinder 2, the torsion arm 3, the tire 4, the strut 5, the connection 6 between the tire and the buffer, the spring element 7 simulating the tire properties, the kinematic pair 8 between the inner and outer cylinders, the damper element and the spring element 9 simulating the buffer between the inner and outer cylinders, and the front traction bar 10 and the rear drag bar 11 on the front landing gear, as shown in Figure 2 .

[0051] The buffer inner cylinder 1 and the buffer outer cylinder 2 use rigid plate shell elements, the torsion arm 3 and the strut 5 use rigid beam elements, and the tire 4 uses a rigid body element to simulate the shape.

[0052] The piston movement between the buffer inner cylinder 1 and the buffer outer cylinder 2 is realized by defining the kinematic pair 8, and the damper element and the spring element 9 in the direction of the piston movement between the inner cylinder 1 and the outer cylinder 2 are used to define the performance of the simulated buffer in absorbing energy and dissipating energy through the imported curve.

[0053] The spring element 7 is arranged between the tire 4 and the buffer, and the mechanical properties of the simulated tire are defined by importing a curve.

[0054] The rear drag bar 11 uses a breakable connection element to simulate the breaking situation according to the set breaking criterion. The breaking criterion is the size of the tension.

[0055] Step three, simplified modeling of the arrestor hook.

[0056] The arrestor hook is simplified and mainly simulated by rigid body elements and damper elements, but the rotation axis between the arrestor hook and the machine body is kept unchanged, the length of the arrestor hook and the position of the hook head are kept unchanged, the rotation between the arrestor hook and the machine body is simulated by using a kinematic pair, and the lateral stabilizer and the roll damping cylinder are simulated by using a damper element.

[0057] The main structures retained for the arrestor hook modeling are the hook body 21, the roll damping-retracting cylinder 22, the hook head 23, the machine body hinge shaft 24, the arrestor hook hinge shaft 25, and the lateral stabilizer 26, as shown in Figure 3 .

[0058] The hook body 21 and the hook head 23 use rigid body elements for simulation.

[0059] The sway-reducing-retracting-actuating-cylinder 22 and the lateral stabilizer 26 are simulated by using damping elements, and the specific performance parameters of the damping elements can be set by importing curves.

[0060] The body hinge axis 24 and the arresting gear hook hinge axis 25 are simulated by using kinematic pairs.

[0061] Step four, the arresting gear rope is simplified and modeled.

[0062] The arresting gear hook is simplified, and only the effect of the rope on the aircraft is considered, without evaluating the strength of the rope itself.

[0063] The arresting gear rope is modeled, and the main structures retained are the first belt element 31 and the second belt element 32.

[0064] The common node 33 at the inner end of the first belt element 31 and the second belt element 32 is connected to a node on the hook head 23 in the arresting gear hook model that is on the longitudinal symmetry plane.

[0065] The first node 34 and the second node 35 at the outer end of the first belt element 31 and the second belt element 32 are constrained.

[0066] According to the actual longitudinal drag force and the geometric parameters such as the angle of the lateral arresting gear rope, the force-displacement relationship of the lateral belt element is obtained, and the properties of the first belt element 31 and the second belt element 32 are defined.

[0067] Step five, the take-off assist device is simplified and modeled.

[0068] The arresting gear hook is simplified, and only the force of the take-off assist device on the aircraft is considered, with the action point being the node of the front tow bar 10 on the catapult track.

[0069] The take-off assist device is modeled, and at the node of the front tow bar 10 on the catapult track, the motion mode is controlled by defining the forced velocity in the vertical and lateral directions to be zero, and the velocity curve in the heading direction is defined.

[0070] At the node of the front tow bar 10 on the catapult track, a lumped mass element is defined to simulate the slider.

[0071] At the node of the front tow bar 10 on the catapult track, the catapult traction force in the heading direction is applied.

[0072] Step six, the runway surface is simplified and modeled.

[0073] The runway surface is modeled, and a certain length and width of quadrilateral plate shell mesh is used to simulate the runway surface 41, and the runway surface 41 is defined as a rigid body and a rigid body constraint is defined, which is completely fixed.

[0074] After the runway surface 41 is created, the aircraft 42 is placed on the upper part of the runway surface 41, defining the contact of the tires 4 with the runway surface 41, taking the runway surface 41 as the main surface, as shown in Figure 5

[0075] The finite element modeling method for the impact response of the aircraft takeoff and landing disclosed in the above embodiment adopts the existing full-aircraft finite element model for the aircraft body, wings, tail and other aircraft structures, and focuses on the simplified modeling of special parts related to the aircraft takeoff and landing. When modeling the landing gear, the mechanical properties of the oil and gas buffer, the restraining rod and the tire are mainly considered, and only the position information and key mechanical properties are retained after the simplified modeling.

[0076] The finite element modeling method for the impact response of the aircraft takeoff and landing disclosed in the above embodiment reduces the modeling difficulty and modeling time through the modularized feasible and rapid simplified method, can quickly establish the finite element model for the aircraft takeoff and landing, controls the key parameters by using a reasonable simplified method, can avoid the solver error caused by unreasonable element type, ensures the accuracy of the simulation result, in addition, the obtained finite element modeling is relatively simplified, can improve the simulation calculation speed, and can meet the needs of engineering design in modeling efficiency, calculation efficiency and calculation accuracy.

[0077] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings, and those skilled in the art should understand that the protection scope of the present application is obviously not limited to these specific embodiments, and those skilled in the art can make equivalent changes or replacements to the related technical features without deviating from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.​

Claims

1. A finite element modeling method of an aircraft landing gear for takeoff and landing impact response, characterized in that, It comprises: Step one, the fuselage, wings, tail, using the existing full machine finite element model; Step two, the landing gear is simplified modeling, retaining the buffer inner tube (1), outer tube (2), torsion arm (3), tire (4), strut (5), the connection between the tire and the buffer (6), spring element (7) simulating the tire characteristics, the motion pair (8) between the inner and outer tube, the damping element and spring element (9) between the inner and outer tube to simulate the buffer, and the front traction rod (10) and the rear traction rod (11) on the front landing gear; Buffer inner tube (1), outer tube (2) using rigid shell element, torsion arm (3), strut (5) using rigid beam element, tire (4) using rigid body element to simulate the shape; Through the definition of motion pair (8) to realize the piston movement between the buffer inner tube (1) and the outer tube (2), and the damping element and spring element (9) between the inner tube (1) and the outer tube (2) in the direction of piston movement, simulate the performance of energy absorption and dissipation of the buffer; Spring element (7) is arranged between tire (4) and buffer, which simulates the mechanical properties of tire; The rear traction rod (11) uses a breakable connection unit to simulate the breaking situation according to the set breaking criterion; Step three, the hook of the arrestor is simplified modeling, retaining the hook body (21), the roll reduction-retracting cylinder (22), the hook head (23), the body hinge shaft (24), the arrestor hook hinge shaft (25), the lateral stabilizer (26); Hook body (21), hook head (23) using rigid body element simulation; Roll reduction-retracting cylinder (22), lateral stabilizer (26) using damping element simulation; Body hinge shaft (24), arrestor hook hinge shaft (25) using motion pair simulation; Step four, the arrestor rope is simplified modeling, retaining the first belt element (31) and the second belt element (32); The common node (33) at the outer end of the first belt element (31) and the second belt element (32) is connected with the node on the hook head (23) in the longitudinal symmetry plane in the arrestor hook model; The first node (34) and the second node (35) at the outer end of the first belt element (31) and the second belt element (32) are constrained; Step five, the take-off booster is simplified modeling, the node of the front traction rod (10) on the catapult rail is controlled by defining the forced velocity as zero in the vertical and lateral directions, and the velocity curve in the heading direction is defined; A concentrated mass unit is defined at the node of the front traction rod (10) on the catapult rail to simulate the slider; The catapult traction force in the heading direction is applied at the node of the front traction rod (10) on the catapult rail; Step six, the runway surface is simplified modeling, the runway surface (41) is simulated by quadrilateral shell grid, and the runway surface (41) is defined as a rigid body and a rigid body constraint is defined, which is completely fixed; The contact between the tire (4) and the runway surface (41) is defined, and the runway surface (41) is the main surface.

2. The finite element modeling method for aircraft take-off and landing impact response according to claim 1, characterized in that, In step 2, the damper element and spring element (9) are defined by importing curves to simulate the energy absorption and dissipation performance of the shock absorber.

3. The finite element modeling method for the impact response of an airplane taking off and landing according to claim 1, characterized in that, In step 2, the spring element (7) is defined by importing curves to simulate the mechanical properties of the tire.

4. The finite element modeling method for the impact response of an airplane taking off and landing according to claim 1, characterized in that, In step 3, the damper element simulating the anti-sway-retractable actuator (22) and the lateral stabilizer (26) is set by importing curves to define the specific performance parameters.

5. The finite element modeling method for the impact response of an airplane taking off and landing according to claim 1, characterized in that, In step 4, the force-displacement relationship of the lateral belt element is obtained according to the actual longitudinal drag force and the angle and geometric parameters of the lateral arresting device rope, and the properties of the first belt element (31) and the second belt element (32) are defined.

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