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A method for analyzing the sensitivity of modal frequency to mas

A technology of sensitivity analysis and modal frequency, which is applied in the field of sensitivity analysis, can solve the problems of large amount of calculation, low sensitivity calculation efficiency, and low efficiency, and achieve the effect of simplifying calculation efficiency

Active Publication Date: 2019-02-01
SOUTHEAST UNIV
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Problems solved by technology

The traditional sensitivity analysis method generally needs to recalculate the finite element calculation under perturbation, especially when the structure is soft and the number of finite elements is large, the calculation amount is large and the efficiency is low
Acceleration signal measurement is relatively common. Sensitivity analysis such as quality parameters based on acceleration admittance information has become a practical engineering problem to be solved if the traditional sensitivity calculation efficiency is low.

Method used

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  • A method for analyzing the sensitivity of modal frequency to mas
  • A method for analyzing the sensitivity of modal frequency to mas
  • A method for analyzing the sensitivity of modal frequency to mas

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Embodiment Construction

[0035] The technical solutions of the present invention will be described in detail below, but the protection scope of the present invention is not limited to the embodiments.

[0036] This example adopts a simple 9-DOF spring-damper-mass structure to verify, such as figure 1 As shown, the parameters of the system are: m i =4kg (i=1,2...9), spring k i =20N / m(i=1,2...9), damper c i =0.02N m / s (i=1, 2…9), the added mass perturbation is Δm=2kg, including the following steps:

[0037] Step 1. Perform finite element analysis based on Matlab software to obtain the acceleration admittance function, construct the admittance matrix, obtain the first 9 modal frequencies, and add mass perturbation items from the first node of the structure;

[0038] 1.1) The degree of freedom of the structure is 9, and the acceleration admittance matrix of the structure is calculated based on the finite element principle:

[0039]

[0040] Among them, a ij Indicates the velocity frequency respons...

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Abstract

The invention provides a method for analyzing the sensitivity of modal frequency to mass. A structure admittance matrix is constructed and the first m-order modal frequency is obtained, the mass perturbation is added from the first node of the structure. The acceleration admittance information is substituted into the matrix modification formula to obtain the acceleration admittance after perturbation, and the frequency information of the structure is extracted to obtain the sensitivity of the structural modal frequency to the mass, and the corresponding sensitivity is obtained by changing theposition of the mass perturbation point according to the node order, so as to obtain the sensitivity of the whole structural modal frequency to the mass. At first, that method of the invention obtainthe acceleration admittance of the structure through the finite element calculation, When the mass of the structure is perturbed, By using the matrix transformation formula, the perturbed accelerationadmittance can be obtained only by numerical calculation of the initial acceleration admittance information without the secondary calculation of the finite element method, which simplifies the calculation efficiency and is more convenient. The fast calculation method of the sensitivity of the acceleration admittance to the mass is realized, which is of practical engineering significance.

Description

technical field [0001] The invention relates to a sensitivity analysis method, in particular to a sensitivity analysis method of modal frequency to mass. Background technique [0002] Sensitivity analysis is a method to evaluate the rate of change of structural response characteristics due to changes in design variables or parameters. The study of structural system sensitivity is a very special field, and it is one of the main research directions in the fields of computational mechanics and structural engineering. [0003] In practical applications, the sensitivity analysis of structures plays an important role in structure optimization, reliability evaluation, and parameter identification. According to the strategy, the methods can be divided into discrete methods and variational methods. Traditional sensitivity analysis methods generally need to perform finite element calculations again under perturbation, especially when the structure is soft and the number of finite ele...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/23G06F2111/10
Inventor 费庆国朱锐姜东杭晓晨曹芝腑
Owner SOUTHEAST UNIV
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