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Non-linear dynamics modeling method for undercarriage buffer

A non-linear dynamics, landing gear buffer technology, applied in the direction of instruments, special data processing applications, electrical digital data processing, etc., can solve the problem of the effective damping of the landing gear buffer, the inability to draw correct conclusions, ground resonance analysis Errors and other issues, to avoid the cost of body weight, improve accuracy, and avoid large errors

Inactive Publication Date: 2014-12-24
CHINA HELICOPTER RES & DEV INST
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Problems solved by technology

[0002] In the analysis of helicopter ground resonance, engineering practice usually adopts a linear processing method based on small disturbances in the equilibrium position, assuming that the dynamic characteristics of the landing gear buffer are linear, so that it is considered in a small amplitude range. From a microscopic point of view, when the actual The result obtained if the amplitude does not exceed this range is correct, but the correct conclusion cannot be drawn for the situation beyond this range
In fact, the stiffness and damping of the landing gear buffer have highly nonlinear characteristics, and are sensitive to environmental changes, especially when the helicopter has a large motion amplitude during takeoff and landing or taxiing at sea, rough roads, gusts, etc., the landing gear The effective damping of the buffer decreases, and the linearization process will bring a large error to the ground resonance analysis

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  • Non-linear dynamics modeling method for undercarriage buffer
  • Non-linear dynamics modeling method for undercarriage buffer
  • Non-linear dynamics modeling method for undercarriage buffer

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specific Embodiment

[0039] Concrete embodiment: take a certain type of helicopter landing gear buffer as an example, adopt the structural configuration and structural parameters of this type of helicopter landing gear buffer, and test data to establish a nonlinear dynamic characteristic model of the buffer, and the specific steps are as follows:

[0040] The first step: the axial force F of the buffer S Expressed as air spring force F a , Internal friction force F f and oil damping force F h the sum of F S =F a +F f +F h .

[0041] Step 2: Calculate the air spring force of the buffer. First, calculate the static stiffness of the buffer. During static compression, the air spring force model of the buffer's low-pressure chamber: Air spring force model for high pressure chamber: F ′ ( s ) = a 1 1 - bS ...

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Abstract

The invention provides a non-linear dynamics modeling method for an undercarriage buffer and belongs to a helicopter theoretical modeling technology. The non-linear dynamics modeling method is characterized in that an undercarriage adopts a double-air-chamber buffering support structure and an axial force of the buffer is represented as the sum of an air spring force, an inner friction force and an oil damping force, and air spring force modeling is carried out to determine the air spring force of a low-pressure cavity of the undercarriage buffer and the air spring force of a high-pressure cavity; an internal friction force and oil damping force model of the buffer is established; a relation of changing an undetermined coefficient in the model along with a compression amount is obtained by using a least square method. By adopting the non-linear dynamics modeling method, the accuracy of the analysis of dynamic characteristics and ground resonance stability of a center of a helicopter propeller hub can be improved; greater errors of the analysis of ground resonance are prevented from being caused by linear processing, and the weight cost of a machine body, caused by the linear processing is avoided.

Description

technical field [0001] The invention belongs to the theoretical modeling technology of a helicopter, and relates to a nonlinear dynamics modeling method of a landing gear buffer used for the analysis of the dynamic characteristics of the hub center of the helicopter and the ground resonance analysis. Background technique [0002] In the analysis of helicopter ground resonance, engineering practice usually adopts a linear processing method based on small disturbances in the equilibrium position, assuming that the dynamic characteristics of the landing gear buffer are linear, so that it is considered in a small amplitude range. From a microscopic point of view, when the actual The results obtained when the amplitude does not exceed this range are correct, but correct conclusions cannot be drawn for situations beyond this range. In fact, the stiffness and damping of the landing gear buffer have highly nonlinear characteristics, and are sensitive to environmental changes, especi...

Claims

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Application Information

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IPC IPC(8): G06F17/50
Inventor 朱艳凌爱民
Owner CHINA HELICOPTER RES & DEV INST
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