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Generalized subspace tracing-based time-varying structure mode parameter identification method

A technology of structural mode and parameter identification, which is applied in the testing of machine/structural components, electrical digital data processing, CAD numerical modeling, etc. big size problem

Active Publication Date: 2018-02-23
XIAN UNIV OF TECH
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  • Abstract
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Problems solved by technology

[0010] In order to solve the time-varying structure with large structure volume, complex operating environment, dense modes and large external interference in the existing technology, the constant modal parameters obtained by using the steady structural mode identification method are difficult to real-time Reflecting the time-varying nature of the structure under strong earthquake excitation, its vibration measurement data usually has a low signal-to-noise ratio, and the recognition accuracy of frequency and mode shape is insufficient, and the robustness of the method is not high. The present invention proposes a A New Time-Varying Modal Parameter Identification Method

Method used

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  • Generalized subspace tracing-based time-varying structure mode parameter identification method
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  • Generalized subspace tracing-based time-varying structure mode parameter identification method

Examples

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Embodiment 1

[0097] Example 1: Modal parameter identification of a four-degree-of-freedom time-varying structure under random excitation

[0098] Use as figure 1 The spring-mass-damping system with 4 degrees of freedom is shown as an example to prove the recognition accuracy, robustness and calculation efficiency of the time-varying modal parameter identification algorithm proposed by the present invention.

[0099] The parameters of the system: m 1 =m 2 =m 3 =1.0kg,m 4 =0.9kg,k 3 =7000N / m,k 2 =k 4 =8000N / m,c 1 = C 2 =0.6N·s 2 / m,c 3 = C 4 =0.55N·s 2 / m, time-varying stiffness coefficient k 1 The changes are as follows,

[0100] Simulation operating condition I: k 1 Is a sudden change,

[0101] (Unit: N / m);

[0102] Simulation operating condition II: k 1 For linear continuous change,

[0103] k 1 =6000+125t, (unit: N / m).

[0104] The initial state of the system is set to zero, and the basic environment encourages a g (t) Use Gaussian white noise excitation to simulate. The calculation of structural...

Embodiment 2

[0164] Example 2: Identification of modal parameters of Pacoima Arch Dam in different earthquakes

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Abstract

The invention relates to a generalized subspace tracing-based time-varying structure mode parameter identification method. The method comprises the following steps of: firstly measuring a vibration response of a structure with a time-varying characteristic, constructing a multi-dimensional time delay vector according to vibration response monitoring data, calculating a related function matrix of the vector, and initializing a generalized subspace tracing algorithm by adoption of feature value decomposition; secondly, carrying out online updating on the related function matrix of the multi-dimensional time delay vector according to new vibration response monitoring data through importing a forgetting factor, and carrying out online updating on an orthogonal matrix pion (k) by adoption of the generalized subspace tracing algorithm; and finally, calculating a discrete state space matrix and an observation matrix at any moment according to the updated orthogonal matrix pion (k), carrying out feature value analysis on the discrete state space matrix, and extracting mode parameters such as a mode frequency, a damping ratio and a vibration mode of the structure. The method is suitable foridentifying mode parameters of time-varying structures in a plurality of fields, and is simple and convenient to use, high in calculation precision, strong in robustness and high in calculation efficiency.

Description

Technical field [0001] The invention specifically relates to a method for identifying time-varying structural modal parameters based on generalized subspace tracing. Background technique [0002] Water conservancy projects, such as the observation of strong earthquakes in dams, use sensors to measure the actual vibration response of the structure under earthquake excitation. The identification of modal parameters of concrete arch dams based on strong earthquake observations can provide a basis for structural seismic analysis, health diagnosis and structural damage assessment after earthquakes. The identification of modal parameters of concrete dams based on strong earthquake observations belongs to the category of structural operational modal analysis (OMA). Modal parameters, such as natural frequency, damping ratio, modal mass, modal stiffness, and modal shape, have obvious physical meanings, and can best reflect the true dynamic characteristics of the dam structure. [0003] Th...

Claims

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Application Information

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IPC IPC(8): G06F17/50G01M7/02
CPCG01M7/00G06F30/20G06F2111/10
Inventor 程琳仝飞李炎隆杨杰郑东健
Owner XIAN UNIV OF TECH
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