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Overall-modal extraction method

An extraction method and modal technology, applied in the field of full arrow modal extraction, can solve the problems of easy error, low efficiency, complicated file data, etc., and achieve the effect of improving efficiency and reducing risks.

Active Publication Date: 2013-12-18
BEIJING INST OF ASTRONAUTICAL SYST ENG +1
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Problems solved by technology

[0002] The dynamic characteristics of the whole arrow structure are generally analyzed by the commercial finite element program Patran / Nastran, and the modal data of the maximum mode shape normalized at the specified point and direction cannot be directly given
The Nastran calculation results.f06 file data is complicated and cannot be directly provided to the attitude control system and POGO stability analysis. The traditional mode extraction method is inefficient and error-prone

Method used

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Embodiment Construction

[0023] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

[0024] The first step is to establish the full arrow structural beam element model;

[0025] a) Collect rocket theoretical diagrams and overall raw data, and establish finite element model nodes and structural mass units according to the structural distribution of core stages and boosters in the rocket theoretical diagrams and the substation information in the overall original data;

[0026] b) Obtain the structural parameters of each section through the structural design drawings of each section, and establish beam elements for simulating structural stiffness;

[0027] c) Collect the propellant mass at each flight time point in the ballistic data, and establish the propellant mass unit;

[0028] d) Assemble the finite element model of the whole arrow on the basis of structural mass element, propellant mass element and beam element, and gener...

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Abstract

The invention relates to an overall-modal extraction method. The overall-modal extraction method includes 1, establishing a beam element model of an overall structure, 2, reading node information and modal order of an overall finite element model and acquiring inherent frequency of modal at different order of the overall finite element model and feature vector related to mass matrix normalization, 3, extracting nodes according to node information, selecting the extracted nodes as major nodes of core pole and assistors, and nodes corresponding to branches of engines and effective load branches, 4, appointing normalized node number, 5, judging main vibration direction, 6, acquiring feature vector and generalized mass normalized according to appointed nodes, and 7, outputting modal results. With the overall-modal extraction method, efficiency of modal extraction is greatly improved and risks caused by failure from manual modal extraction are reduced.

Description

technical field [0001] The invention relates to a method for extracting the mode of a whole rocket, in particular to a method for extracting mode parameters of a launch vehicle and a liquid missile. Background technique [0002] The dynamic characteristics of the whole arrow structure are generally analyzed by the commercial finite element program Patran / Nastran, which cannot directly give the modal data of the maximum mode shape normalized at the specified point and direction. The Nastran calculation result .f06 file has complicated data and cannot be directly provided to the attitude control system and POGO stability analysis. The traditional mode extraction method is inefficient and error-prone. Therefore, it is urgent to provide a new method for full-arrow mode extraction. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a full arrow mode extraction method which improves the efficiency of mode extraction work...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
Inventor 潘忠文王旭廉永正杨树涛董锴孙目曾耀祥
Owner BEIJING INST OF ASTRONAUTICAL SYST ENG
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