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Random vibration analysis and calculation method of free body multi-point correlated pulsating pressures

A technology of pulsating pressure and random vibration, applied in calculation, design optimization/simulation, special data processing applications, etc., can solve problems such as difficulty in effectively simulating the real structural response of aircraft free state, complex random vibration analysis algorithm, etc.

Active Publication Date: 2017-12-15
GENERAL ENG RES INST CHINA ACAD OF ENG PHYSICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] c) Complexity of free body random vibration analysis algorithm
Traditional calculations are mainly aimed at random vibration analysis including constrained boundaries, and it is difficult to effectively simulate the real structural response of the free state of the aircraft

Method used

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  • Random vibration analysis and calculation method of free body multi-point correlated pulsating pressures
  • Random vibration analysis and calculation method of free body multi-point correlated pulsating pressures
  • Random vibration analysis and calculation method of free body multi-point correlated pulsating pressures

Examples

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Embodiment 1

[0315] Example 1: Random vibration analysis of multi-point fluctuating pressure in sector-shaped free-body structure

[0316] Description of the problem: The finite element model of the entire fan-shaped body is as follows: figure 1 As shown, the length of the left end in the Y direction is 1.75m, the length of the right end in the X direction is 1.25m, and the thickness in the Z direction is 0.6m. It is in an unconstrained free state, and bears two related pulsating pressure loads at the left and right ends. The fan-shaped body adopts a material (steel), and the corresponding material parameters have an elastic modulus of 210GPa, a density of 7800Kg / m3, and a Poisson's ratio of 0.3. The modal damping ratio of each order is taken as 0.02. The analysis frequency is from 1Hz to 1000Hz, and the load self-spectrum and cross-spectrum curves corresponding to the two end faces are obtained as follows: figure 2 As shown, using the white direct spectrum, the amplitude of the autospe...

Embodiment 2

[0330] Example 2: Random vibration analysis of typical aircraft multi-point pulsation pressure

[0331] Description of the problem: As a typical application example, the present invention takes a typical declassified aircraft as an example, and develops the random vibration power spectral density response and full Field mean square response. Figure 7 and Figure 8 It is a schematic diagram of the finite element model of the aircraft including the counterweight structure and the distribution of the pulsating pressure. Starting from the front section of the aircraft, the pulsating pressure is divided into five annular areas (each area is marked with a different color), and each area bears different pulsating pressure loads. There is a cross-correlation between the pulsating pressures in two adjacent regions.

[0332] The pulsating pressure self-power spectrum input is divided into pressure self-power spectral density curves corresponding to five sections, and cross-power spec...

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Abstract

The invention discloses a random vibration analysis and calculation method of free body multi-point correlated pulsating pressures. The method comprises the steps that firstly, a finite element discrete model of free body structure dynamics is established; secondly, modal analysis of a free body is conducted; thirdly, a dynamic equation of rigid body motion and elastic motion of a free body structure is established; fourthly, corresponding modal of the pulsating pressures participates in the calculation of coefficients; fifthly, the random vibration power spectral density response calculation is conducted on the rigid body response, the elastic response and the coupling response under the pulsing pressure effect; sixthly, root mean square equivalent response of the whole structure is calculated. The random vibration analysis and calculation method has the advantages that the proposed method is fast in calculation speed, easy to expand and large in computation scale and the like, meanwhile considering the influence of the rigid body modal and the elastic modal, the response characteristic of an aircraft reentering a flying process is more accurately simulated, and the fast vibration response can be solved for the fine finite element model of an aircraft structure.

Description

technical field [0001] The invention relates to the field of numerical calculation of aircraft structural dynamics, in particular to a random vibration analysis and calculation method of multi-point correlation pulsation pressure random vibration of a free body under the action of air pulsation pressure in the process of typical flight re-entry into the atmosphere. Background technique [0002] The random vibration analysis of free body multi-point correlation pulsating pressure involved in the present invention refers specifically to weapons, typical aircraft in the field of aerospace, etc. after the ground launch stage and vacuum flight stage, and the structure is subjected to air pulsation pressure during the re-entry process. Steady-state random vibration response calculations. [0003] After the aircraft undergoes launch, free flight outside the atmosphere and re-entry into the atmosphere, the outer surface of the aircraft is subjected to various loads such as time-aver...

Claims

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Application Information

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IPC IPC(8): G06F17/50
CPCG06F30/15G06F30/23Y02T90/00
Inventor 范宣华王柯颖肖世富李上明沈展鹏陈红永王东
Owner GENERAL ENG RES INST CHINA ACAD OF ENG PHYSICS
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