復雜追蹤識別結構參數(shù)及損傷
發(fā)布時間：2018-08-14 15:17
【摘要】：近年來國家對基礎設施的投資規(guī)模不斷擴大,各種大型復雜結構不斷涌現(xiàn)。它們在服役期間,由于外界和自身因素的影響,不可避免地發(fā)生損傷。為了及早發(fā)現(xiàn)結構損傷,降低對人們生命及財產安全的威脅,一個有效的手段就是在大型結構上安裝健康監(jiān)測系統(tǒng)。作為結構健康監(jiān)測系統(tǒng)的核心內容,結構參數(shù)識別和損傷識別一直是國內外學者的研究焦點,致力于尋找一種大型復雜結構在線監(jiān)測的損傷診斷方法。本文將復雜追蹤算法應用于土木工程結構模態(tài)參數(shù)和損傷識別中,為結構識別提供新思路,豐富和完善結構健康監(jiān)測理論。本文主要研究內容及成果如下:(1)闡述了本課題的研究背景及意義,對當前結構模態(tài)參數(shù)識別和損傷識別的研究方法及存在的問題進行了系統(tǒng)論述,并簡單介紹了盲源分離的發(fā)展及在結構識別中的應用。(2)簡單介紹了復雜追蹤的相關數(shù)學知識、基本原理、預處理方法,并對目標函數(shù)的建立以及梯度優(yōu)化算法進行了論述。原梯度算法迭代過程使用固定步長和非線性函數(shù),使得算法的自適應性不足。為此,根據峭度及最優(yōu)步長對原梯度算法的迭代過程進行了改進,形成了適用性更廣、分離效果更好的自適應復雜追蹤算法。(3)發(fā)展出復雜追蹤結合希爾伯特變換識別結構模態(tài)參數(shù)的新方法。對多自由度結構系統(tǒng)動力響應與復雜追蹤模型之間的關系進行了探討,通過復雜追蹤算法分離出結構的各階模態(tài)響應及振型,再利用希爾伯特變換解析出結構的模態(tài)頻率及阻尼比。采用不同的模型驗證了該方法準確識別結構模態(tài)參數(shù)的可靠性。(4)發(fā)展出復雜追蹤結合集合經驗模態(tài)分解識別結構損傷的新方法。結構損傷會引起響應信號的突變,通過集合經驗模態(tài)分解提取包含損傷分量的高頻本征模函數(shù),再利用復雜追蹤算法,從噪聲信號中分離出該損傷分量。根據信號突變點的位置識別損傷發(fā)生的時間,再根據混合矩陣識別損傷發(fā)生的位置。通過不同的模型,驗證了該方法可準確有效地識別結構損傷發(fā)生的時刻與位置。
[Abstract]:In recent years, the scale of national investment in infrastructure has been expanding, and various large and complex structures are emerging. During their service, injuries inevitably occur due to the influence of external and self-factors. In order to detect structural damage as early as possible and reduce the threat to people's life and property, an effective method is to install health monitoring system on large structures. As the core of structural health monitoring system, structural parameter identification and damage identification have been the research focus of scholars at home and abroad, dedicated to find a large and complex structure online monitoring damage diagnosis method. In this paper, the complex tracking algorithm is applied to the modal parameters and damage identification of civil engineering structures, which provides a new idea for structural identification and enriches and perfects the theory of structural health monitoring. The main contents and achievements of this paper are as follows: (1) the research background and significance of this subject are expounded, and the research methods and existing problems of structural modal parameter identification and damage identification are systematically discussed. The development of blind source separation and its application in structure recognition are briefly introduced. (2) the mathematical knowledge, basic principle, preprocessing method of complex tracing are briefly introduced, and the establishment of objective function and gradient optimization algorithm are discussed. The iterative process of the original gradient algorithm uses fixed step size and nonlinear function, which makes the algorithm self-adaptive. Therefore, the iterative process of the original gradient algorithm is improved according to the kurtosis and the optimal step size, resulting in a wider applicability. An adaptive complex tracking algorithm with better separation effect is proposed. (3) A new method of identifying structural modal parameters by complex tracing combined with Hilbert transform is developed. The relationship between dynamic response and complex tracking model of multi-degree-of-freedom structural system is discussed. The modal responses and modes of structures are separated by complex tracking algorithm. Then the modal frequency and damping ratio of the structure are analyzed by Hilbert transform. Different models are used to verify the reliability of the method. (4) A new method is developed to identify structural damage with complex tracing and set empirical mode decomposition. Structural damage can cause sudden change of response signal. The high frequency eigenmode function containing damage component is extracted by means of set empirical mode decomposition, and the damage component is separated from noise signal by complex tracking algorithm. The time of damage is identified according to the location of the signal mutation point, and then the location of the damage is identified according to the mixed matrix. Through different models, it is verified that the method can accurately and effectively identify the time and position of structural damage.
【學位授予單位】：蘇州科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU317
本文編號：2183272
[Abstract]:In recent years, the scale of national investment in infrastructure has been expanding, and various large and complex structures are emerging. During their service, injuries inevitably occur due to the influence of external and self-factors. In order to detect structural damage as early as possible and reduce the threat to people's life and property, an effective method is to install health monitoring system on large structures. As the core of structural health monitoring system, structural parameter identification and damage identification have been the research focus of scholars at home and abroad, dedicated to find a large and complex structure online monitoring damage diagnosis method. In this paper, the complex tracking algorithm is applied to the modal parameters and damage identification of civil engineering structures, which provides a new idea for structural identification and enriches and perfects the theory of structural health monitoring. The main contents and achievements of this paper are as follows: (1) the research background and significance of this subject are expounded, and the research methods and existing problems of structural modal parameter identification and damage identification are systematically discussed. The development of blind source separation and its application in structure recognition are briefly introduced. (2) the mathematical knowledge, basic principle, preprocessing method of complex tracing are briefly introduced, and the establishment of objective function and gradient optimization algorithm are discussed. The iterative process of the original gradient algorithm uses fixed step size and nonlinear function, which makes the algorithm self-adaptive. Therefore, the iterative process of the original gradient algorithm is improved according to the kurtosis and the optimal step size, resulting in a wider applicability. An adaptive complex tracking algorithm with better separation effect is proposed. (3) A new method of identifying structural modal parameters by complex tracing combined with Hilbert transform is developed. The relationship between dynamic response and complex tracking model of multi-degree-of-freedom structural system is discussed. The modal responses and modes of structures are separated by complex tracking algorithm. Then the modal frequency and damping ratio of the structure are analyzed by Hilbert transform. Different models are used to verify the reliability of the method. (4) A new method is developed to identify structural damage with complex tracing and set empirical mode decomposition. Structural damage can cause sudden change of response signal. The high frequency eigenmode function containing damage component is extracted by means of set empirical mode decomposition, and the damage component is separated from noise signal by complex tracking algorithm. The time of damage is identified according to the location of the signal mutation point, and then the location of the damage is identified according to the mixed matrix. Through different models, it is verified that the method can accurately and effectively identify the time and position of structural damage.
【學位授予單位】：蘇州科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU317
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