Finite element modeling method for taking-off and landing impact response of airplane

Abstract

The invention 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 the modeling difficulty and the modeling time through a modularized feasible and rapid simplification method, can rapidly establish a finite element model for aircraft take-off and landing impact, and improves the modeling efficiency. A reasonable simplification method is adopted to control key parameters, solver error reporting caused by unreasonable unit types and the like can be avoided, the precision of simulation results is guaranteed, in addition, obtained finite element modeling is simplified, the speed of simulation calculation can be increased, and the requirements of engineering design can be met in modeling efficiency, calculation efficiency and calculation precision.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft takeoff and landing impact response analysis, and specifically relates to a finite element modeling method for aircraft takeoff and landing impact response. Background Art

[0002] When an aircraft lands or takes off from a ship, a large load impact will occur in a short period of time, which may cause damage to the fuselage structure and seriously threaten the flight safety of the aircraft. This is an important working condition for aircraft strength analysis. At the same time, the dynamic response of various parts of the fuselage during takeoff and landing is also a typical environment that needs to be covered by mechanical environmental testing.

[0003] At present, explicit dynamics simulation methods are mainly used for the simulation of impact dynamic response of aircraft takeoff and landing. The explicit dynamics simulation method has great advantages in dynamic response calculation, such as large displacement and large rotation, simulation of structural collision, and simulation of nonlinear oil damping, but it is not perfect in the pre-processing function of finite element, and there is no finite element fast modeling method for the impact response of aircraft takeoff and landing.

[0004] This application is proposed in view of the above-mentioned technical defects. Summary of the invention

[0005] The purpose of this application is to provide a finite element modeling method for the impact response of aircraft takeoff and landing, and to quickly establish an explicit dynamic finite element model through a modular simplification method to provide accurate analysis of the impact dynamic response of the entire aircraft when intercepting a missile.

[0006] The technical solution of this application is:

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

[0008] Step 1: Use the existing full-aircraft finite element model for the fuselage, wings, and tail;

[0009] Step 2: Simplify the modeling of the landing gear, retain the inner and outer cylinders of the buffer, the torque arm, the tire, the strut, the connection between the tire and the buffer, the spring element simulating the tire characteristics, the kinematic pair between the inner and outer cylinders, the damping element and spring element simulating the buffer between the inner and outer cylinders, and the front traction rod and rear check rod on the front landing gear;

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

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

[0012] The spring element is set between the tire and the buffer to simulate the mechanical properties of the tire;

[0013] The rear check rod uses a breakable connection unit to simulate the break situation according to the set break criteria;

[0014] Step 3: Simplify the modeling of the parking aid hook, retaining the hook body, the swing reduction-retraction actuator, the hook head, the body articulation axis, the parking aid hook articulation axis, and the lateral stabilizer;

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

[0016] The sway reduction-retraction actuator and lateral stabilizer are simulated using damping elements;

[0017] The body articulated axis and the auxiliary parking device hook articulated axis are simulated by kinematic pairs;

[0018] Step 4: Simplify the modeling of the rope of the parking aid device, and retain the first belt element and the second belt element;

[0019] The common node at the inner ends of the first belt element and the second belt element is connected to the node on the longitudinal symmetry plane of the hook head in the hook model of the auxiliary parking device;

[0020] Constraining the first node and the second node at the outer ends of the first band element and the second band element;

[0021] Step 5: Simplify the modeling of the takeoff assist device, control the motion mode of the node of the front traction rod on the ejection rail by defining the vertical and lateral forced speeds to be zero, and define the speed curve in the heading direction;

[0022] At the node of the front traction rod on the ejection slide, a concentrated mass unit is defined to simulate the slide;

[0023] At the node of the front traction rod on the ejection slide rail, an ejection traction force in the heading direction is applied;

[0024] Step 6: Simplify the modeling of the runway surface, simulate the runway surface with a quadrilateral plate-shell mesh, define the runway surface as a rigid body, and define rigid body constraints to make it completely fixed;

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

[0026] Optionally, in the above-mentioned finite element modeling method for the impact response of aircraft takeoff and landing, in step 2, the damping element and the spring element are defined by imported curves to simulate the performance of absorbing and dissipating energy of the buffer.

[0027] Optionally, in the above-mentioned finite element modeling method for the impact response of aircraft takeoff and landing, in step 2, the spring element is defined by importing a curve to simulate the mechanical properties of the tire.

[0028] Optionally, in the above-mentioned finite element modeling method of the impact response of aircraft takeoff and landing, in step three, the damping elements of the sway reduction-retraction actuator and the lateral stabilizer are simulated, and the specific performance parameters are set by importing curves.

[0029] Optionally, in the above-mentioned finite element modeling method of the impact response of aircraft takeoff and landing, in step four, the force-displacement relationship of the lateral belt element is obtained according to the actual longitudinal arresting resistance and the angular geometric parameters of the lateral parking aid rope, and the properties of the first belt element and the second belt element are defined.

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

[0031] A finite element modeling method for aircraft takeoff and landing impact response is provided. Through a modular, feasible and fast simplification method, the modeling difficulty and modeling time are reduced, and a finite element model for aircraft takeoff and landing impact can be established relatively quickly. A reasonable simplification method is used to control key parameters, which can avoid solver errors caused by unreasonable unit types and the like, and ensure the accuracy of simulation results. In addition, the resulting finite element modeling is relatively simplified, which can improve the speed of simulation calculations and meet the needs of engineering design in terms of modeling efficiency, calculation efficiency and calculation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of a finite element modeling method for an aircraft takeoff and landing impact response provided in an embodiment of the present application;

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

[0034] Figure 3 is a schematic diagram of simplified modeling of a hook of a parking aid device provided in an embodiment of the present application;

[0035] Figure 4 is a schematic diagram of simplified modeling of the rope of the parking aid device provided in an embodiment of the present application;

[0036] Figure 5 It is a schematic diagram of simplified modeling of a takeoff assist device provided in an embodiment of the present application.

[0037] In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be construed as limitations on the present application. DETAILED DESCRIPTION

[0038] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0039] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0040] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0041] Before establishing the finite element model of the impact response of the aircraft intercepting the missile, there is usually a finite element model of the whole aircraft for static analysis or other dynamic analysis. Modifying the existing whole aircraft model and establishing the finite element model of the impact response of the aircraft intercepting the missile can save a lot of manpower and time. However, the following key technical issues need to be solved:

[0042] The first is how to simplify the landing gear and retain the core parameters;

[0043] The second is a simplified modeling method for the hook of the auxiliary parking device;

[0044] The third is a simplified modeling method for the rope of the auxiliary parking device;

[0045] Fourth, a simplified modeling method for the takeoff assist device.

[0046] After simplifying the landing gear, the parking aid hook, the parking aid rope, and the take-off assist device, the simulation accuracy of physical quantities such as displacement, acceleration, stress, and strain on the fuselage should be guaranteed. In this regard, an embodiment of the present application provides a finite element modeling method for the impact response of aircraft take-off and landing, including the following steps.

[0047] Step 1: Use the existing finite element model of the entire aircraft for the fuselage, wings, tail and other aircraft structures.

[0048] Step 2: Simplify the modeling of the landing gear.

[0049] According to the purpose of simulation analysis, the landing gear part focuses on the mechanical properties of the oil and gas buffer, the check rod and the tire. After simplifying the modeling, only the position information and key mechanical properties are retained.

[0050] The landing gear modeling mainly retains the following structures: the inner and outer cylinders 1, 2, torque arms 3, tires 4, struts 5, the connection between the tires and the buffers 6, the spring element 7 simulating the tire characteristics, the kinematic pair 8 between the inner and outer cylinders, the damping element and spring element 9 simulating the buffer between the inner and outer cylinders, and the front traction rod 10 and the rear check rod 11 on the front landing gear. Figure 2 shown.

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

[0052] The piston movement between the inner cylinder 1 and the outer cylinder 2 of the buffer is realized by defining a kinematic pair 8, and a damping element and a spring element 9 in the direction of the piston movement are used between the inner cylinder 1 and the outer cylinder 2. The energy absorption and energy dissipation performance of the simulated buffer are defined by the imported curve.

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

[0054] The rear check rod 11 uses a breakable connection unit to simulate a break situation according to a set break criterion. The break criterion is the magnitude of the pulling force.

[0055] Step 3: Simplify the modeling of the hook of the parking aid device.

[0056] In order to simplify the hook of the parking aid device, rigid body elements and damping elements can be mainly used for simulation. However, the rotation axis between the hook of the parking aid device and the body should be kept unchanged, and the length of the hook of the parking aid device and the position of the hook head should be kept unchanged. Kinematic pairs can be used to simulate the rotation between the hook of the parking aid device and the body, and damping elements can be used to simulate the lateral stabilizer and the sway reduction actuator.

[0057] The auxiliary parking device hook is modeled, and the main structures retained include the hook body 21, the swing reduction-retraction actuator 22, the hook head 23, the body articulation axis 24, the auxiliary parking device hook articulation axis 25, and the lateral stabilizer 26. Figure 3 shown.

[0058] The hook body 21 and the hook head 23 are simulated by rigid body elements.

[0059] The sway reduction-retraction actuator 22 and the lateral stabilizer 26 are simulated by damping elements, wherein specific performance parameters of the damping elements can be set by importing curves.

[0060] The machine body articulated shaft 24 and the parking aid hook articulated shaft 25 are simulated by kinematic pairs.

[0061] Step 4: Simplify the modeling of the auxiliary parking device rope.

[0062] By simplifying the hook of the parking aid, only the effect of the cable on the aircraft can be considered without evaluating the strength of the cable itself.

[0063] The rope of the parking aid device 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 ends of the first belt element 31 and the second belt element 32 is connected to a node on the longitudinal symmetry plane on the hook head 23 in the hook model of the parking aid device.

[0065] Constraints are imposed on the first node 34 and the second node 35 at the outer ends of the first band element 31 and the second band element 32 .

[0066] According to the actual longitudinal arresting force and geometric parameters such as the angle of the rope of the lateral parking aid, 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 5: Simplify the modeling of the take-off assist device.

[0068] The hook of the parking aid device is simplified, and only the force of the take-off assist device on the aircraft is considered, and the point of action is the node of the front traction rod 10 on the ejection rail.

[0069] The take-off assist device is modeled, and the node of the front traction rod 10 on the ejection slide rail is controlled by defining the vertical and lateral forced velocities to be zero, and a velocity curve is defined in the heading direction.

[0070] At the node of the front traction rod 10 on the ejection slide rail, a concentrated mass unit is defined to simulate the slide.

[0071] At the node of the front traction rod 10 on the ejection slide rail, an ejection traction force in the heading direction is applied.

[0072] Step 6: Simplify the runway surface modeling.

[0073] The runway surface is modeled, and the runway surface 41 is simulated using a quadrilateral plate-shell mesh of a certain length and width. The runway surface 41 is defined as a rigid body, and rigid body constraints are defined to be completely fixed.

[0074] After the runway surface 41 is created, the aircraft 42 is placed on the upper part of the runway surface 41, and the contact between the tire 4 and the runway surface 41 is defined, with the runway surface 41 as the main surface. Figure 5 shown.

[0075] The finite element modeling method for the impact response of aircraft takeoff and landing disclosed in the above-mentioned embodiment adopts the existing full-aircraft finite element model for the fuselage, wings, tail wing and other body structures, and focuses on simplifying the modeling of special parts related to the impact of aircraft takeoff and landing. Among them, when modeling the landing gear, the mechanical properties of the oil and gas buffer, the check rod and the tire are focused on. After simplified modeling, only the position information and key mechanical properties are retained.

[0076] The finite element modeling method for the impact response of aircraft takeoff and landing disclosed in the above-mentioned embodiment reduces the difficulty and time of modeling through a modular, feasible and fast simplification method, and can relatively quickly establish a finite element model for aircraft takeoff and landing. It uses a reasonable simplification method to control key parameters, which can avoid solver errors caused by unreasonable unit types, thereby ensuring the accuracy of simulation results. In addition, the resulting finite element modeling is relatively simplified, which can improve the speed of simulation calculations and meet the needs of engineering design in terms of modeling efficiency, calculation efficiency and calculation accuracy.

[0077] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A finite element modeling method for aircraft takeoff and landing impact response, characterized in that: include: Step 1: Use the existing full-aircraft finite element model for the fuselage, wings, and tail; Step 2: Simplify the modeling of the landing gear, retain the inner cylinder (1) and outer cylinder (2) of the buffer, the torque arm (3), the tire (4), the strut (5), the connection between the tire and the buffer (6), the spring element simulating the tire characteristics (7), the kinematic pair between the inner and outer cylinders (8), the damping element and spring element (9) simulating the buffer between the inner and outer cylinders, and the front traction rod (10) and the rear check rod (11) on the front landing gear; The inner cylinder (1) and the outer cylinder (2) of the buffer use rigid plate-shell elements, the torsion arm (3) and the strut (5) use rigid beam elements, and the tire (4) uses rigid body elements to simulate the shape; The piston movement between the inner cylinder (1) and the outer cylinder (2) of the buffer is realized by defining a kinematic pair (8), and a damping element and a spring element (9) in the piston movement direction are used between the inner cylinder (1) and the outer cylinder (2) to simulate the energy absorption and energy dissipation performance of the buffer; The spring element (7) is arranged between the tire (4) and the buffer to simulate the mechanical properties of the tire; The rear check rod (11) uses a breakable connection unit to simulate a break situation according to a set break criterion; Step 3: Simplify the modeling of the parking aid hook, retaining the hook body (21), the swing reduction-retraction actuator (22), the hook head (23), the body articulation axis (24), the parking aid hook articulation axis (25), and the lateral stabilizer (26); The hook body (21) and the hook head (23) are simulated by rigid body elements; The sway reduction-retraction actuator (22) and the lateral stabilizer (26) are simulated by damping elements; The machine body articulated shaft (24) and the parking aid hook articulated shaft (25) are simulated by kinematic pairs; Step 4: Simplify the modeling of the rope of the parking aid device, and retain the first belt element (31) and the second belt element (32); A common node (33) at the inner ends of the first belt element (31) and the second belt element (32) is connected to a node on the hook head (23) in the hook model of the auxiliary parking device and located on the longitudinal symmetry plane; Constraining the first node (34) and the second node (35) at the outer ends of the first band element (31) and the second band element (32); Step 5: Simplify the modeling of the take-off assist device, control the motion mode of the node of the front traction rod (10) on the ejection rail by defining the vertical and lateral forced velocities to be zero, and define the velocity curve in the heading direction; At the node of the front traction rod (10) on the ejection slide rail, a concentrated mass unit is defined to simulate the slide; Applying a heading ejection traction force at a node of the front traction rod (10) on the ejection slide rail; Step 6: Simplify the modeling of the runway surface, simulate the runway surface (41) with a quadrilateral plate-shell mesh, define the runway surface (41) as a rigid body, and define rigid body constraints to be completely fixed; The contact between the tire (4) and the runway surface (41) is defined, with the runway surface (41) being the main surface.

2. The finite element modeling method for aircraft takeoff and landing impact response according to claim 1, characterized in that: In step 2, the damping element and the spring element (9) are defined by the imported curves to simulate the energy absorption and energy dissipation performance of the buffer.

3. The finite element modeling method for aircraft takeoff and landing impact response according to claim 1, characterized in that: In step 2, the spring element (7) is defined by importing a curve to simulate the mechanical properties of the tire.

4. The finite element modeling method for aircraft takeoff and landing impact response according to claim 1, characterized in that: In step three, the damping element of the sway reduction-retraction and extension actuator (22) and the lateral stabilizer (26) is simulated, and the specific performance parameters are set by importing the curve.

5. The finite element modeling method for aircraft takeoff and landing impact response according to claim 1, characterized in that: In step 4, the force-displacement relationship of the transverse belt element is obtained according to the actual longitudinal arresting force and the angular geometric parameters of the transverse parking aid rope, and the properties of the first belt element (31) and the second belt element (32) are defined.

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