發(fā)布時間：2018-11-03 19:54

【摘要】：機械結(jié)構(gòu)在使用過程中,將會受到正常工作載荷的作用以及各種突發(fā)性外在因素影響而出現(xiàn)局部損傷。當局部損傷積累到一定程度時,會導致整體結(jié)構(gòu)的突然失效。對于重要結(jié)構(gòu),損傷的發(fā)生以及機械結(jié)構(gòu)的失效將引起重大的安全事故和經(jīng)濟損失。因此,為保證機械結(jié)構(gòu)的安全與系統(tǒng)的正常工作,需要定期或在線對機械結(jié)構(gòu)進行損傷檢測,盡早地發(fā)現(xiàn)損傷發(fā)生的位置和程度,對結(jié)構(gòu)實時進行修復或改進,避免災(zāi)難性事故的發(fā)生。 本文從工程實際應(yīng)用出發(fā),將應(yīng)變模態(tài)方法與工作模態(tài)理論相結(jié)合應(yīng)用于機械結(jié)構(gòu)的損傷檢測中。具體研究過程如下： 1、通過分析結(jié)構(gòu)損傷識別方法的研究現(xiàn)狀和存在的問題,結(jié)合具體研究對象對應(yīng)變模態(tài)分析方法做了詳細的研究。 2、通過間接損傷診斷數(shù)值仿真、實驗研究,得出損傷位置、程度對模態(tài)參數(shù)(頻率、阻尼、振型)的一般影響規(guī)律。 本文以應(yīng)變模態(tài)振型和應(yīng)變模態(tài)差為損傷識別指標對懸臂梁損傷進行了有效的識別。應(yīng)變模態(tài)振型對非模態(tài)節(jié)點損傷非常敏感,尤其是對損傷發(fā)生在某階模態(tài)峰值區(qū)附近時。在損傷附近應(yīng)變模態(tài)發(fā)生突變,并且突變程度隨損傷量的增加而增大。 3、由加速度信號推算應(yīng)變模態(tài)。 根據(jù)材料力學縱應(yīng)變理論,得出應(yīng)變與位移的關(guān)系。位移信號可以由加速時信號經(jīng)兩次積分得到。從加速度信號推導出應(yīng)變模態(tài),并從誤差的角度分析了這種方法的可行性。計算過程中主要誤差來源為兩測點信號相減過程中的相位誤差。為了減小這種相位誤差,提出了一種基于最小方差的處理方法,并通過實驗驗證了這種方法的可行性。該方法可以使以后的測試及診斷更加方便有效。 4、將應(yīng)變模態(tài)與工作模態(tài)綜合運用于結(jié)構(gòu)的損傷檢測中。 本文將應(yīng)變模態(tài)和工作模態(tài)相結(jié)合,闡述了應(yīng)變工作模態(tài)的基本原理及頻域參數(shù)識別方法。針對應(yīng)變模態(tài)與工作模態(tài)相結(jié)合的研究方法提出新的研究路徑,并通過懸臂梁實驗驗證了這種方法的可行性 總體來說,本文將應(yīng)變模態(tài)分析方法和工作模態(tài)的基本理論應(yīng)用于機械結(jié)構(gòu)的損傷檢測中,通過理論的分析推導和實驗驗證,對所提方法的可行性和有效性進行了分析研究。
[Abstract]:In the process of use, the mechanical structure will be affected by the normal working load and a variety of sudden external factors, resulting in local damage. When the local damage accumulates to a certain extent, it will lead to the sudden failure of the whole structure. For important structures, the occurrence of damage and the failure of mechanical structures will cause serious safety accidents and economic losses. Therefore, in order to ensure the safety of the mechanical structure and the normal work of the system, it is necessary to detect the damage of the mechanical structure on a regular or online basis, to find out the location and extent of the damage as soon as possible, and to repair or improve the structure in real time. Avoid catastrophic accidents. In this paper, the strain mode method is combined with the working mode theory to detect the damage of mechanical structures. The specific research process is as follows: 1. By analyzing the present situation and existing problems of structural damage identification methods, the strain modal analysis method is studied in detail. 2. Through numerical simulation of indirect damage diagnosis and experimental study, the general influence of damage location and degree on modal parameters (frequency, damping, mode shape) is obtained. In this paper, the damage of cantilever beam is effectively identified by using strain mode and strain mode difference as damage identification index. The strain mode is very sensitive to the damage of the non-modal node, especially when the damage occurs near the peak value of a certain mode. A mutation occurs in the strain mode near the damage, and the degree of the mutation increases with the increase of the damage. The strain mode is calculated from the acceleration signal. According to the theory of longitudinal strain in mechanics of materials, the relationship between strain and displacement is obtained. The displacement signal can be obtained from the acceleration signal by two integrals. The strain mode is derived from the acceleration signal and the feasibility of this method is analyzed from the angle of error. The main source of error in the calculation process is the phase error in the process of signal subtraction between two measuring points. In order to reduce the phase error, a processing method based on minimum variance is proposed, and the feasibility of this method is verified by experiments. This method can make the later test and diagnosis more convenient and effective. 4. The strain mode and the working mode are applied to the damage detection of the structure. In this paper, the basic principle of strain working mode and the identification method of frequency domain parameters are expounded by combining the strain mode with the working mode. A new research path is proposed for the combination of strain mode and working mode, and the feasibility of this method is verified by cantilever beam experiment. In this paper, the strain mode analysis method and the basic theory of working mode are applied to the damage detection of mechanical structures. The feasibility and validity of the proposed method are analyzed and studied by theoretical analysis and experimental verification.
【學位授予單位】：太原理工大學
【學位級別】：碩士
【學位授予年份】：2011
【分類號】：TH165.3

【參考文獻】

相關(guān)期刊論文 前9條

1 王文靜,劉志明,繆龍秀;基于實驗?zāi)B(tài)的結(jié)構(gòu)應(yīng)變模態(tài)分析[J];北方交通大學學報;2000年04期

2 陳淮,禹丹江;基于曲率模態(tài)振型進行梁式橋損傷識別研究[J];公路交通科技;2004年10期

3 劉暉,瞿偉廉,袁潤章;基于應(yīng)變能耗散率的結(jié)構(gòu)損傷識別方法研究[J];工程力學;2004年05期

4 郭國會,范培生,易偉進;基于振型變化的框架結(jié)構(gòu)破損評估[J];重慶建筑大學學報;1998年06期

5 李德葆,諸葛鴻程,王波;實驗應(yīng)變模態(tài)分析原理和方法[J];清華大學學報(自然科學版);1990年02期

6 瞿偉廉,陳超,魏文輝;基于應(yīng)變模態(tài)的鋼結(jié)構(gòu)構(gòu)件焊縫損傷定位方法的研究[J];世界地震工程;2002年02期

7 李中付,華宏星,宋漢文,陳之炎;非穩(wěn)態(tài)環(huán)境激勵下線性結(jié)構(gòu)的模態(tài)參數(shù)辨識[J];振動工程學報;2002年02期

8 姜德生,羅裴,梁磊;光纖布拉格光柵傳感器與基于應(yīng)變模態(tài)理論的結(jié)構(gòu)損傷識別[J];儀表技術(shù)與傳感器;2003年02期

9 顧培英;陳厚群;李同春;鄧昌;;基于損傷應(yīng)變模態(tài)的結(jié)構(gòu)損傷識別直接指標法[J];自然科學進展;2007年02期

相關(guān)博士學位論文 前1條

1 顧培英;基于應(yīng)變模態(tài)技術(shù)的結(jié)構(gòu)損傷診斷直接指標法研究[D];河海大學;2006年

，

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