基于小波和振動模態(tài)分析的正放四角錐網(wǎng)架結構損傷檢測研究
發(fā)布時間：2018-08-07 16:04
【摘要】：近些年來,我國在經(jīng)濟迅速發(fā)展的推動下,建筑技術不斷提高,建成了一大批規(guī)模宏大、形式新穎的大跨度空間結構(如體育館、航站樓、展覽中心等)。由于大跨度空間結構往往人群聚集,而且有些場所配置重要設施,因此結構一旦出現(xiàn)損傷、發(fā)生破壞將造成重大的人員傷亡事故。大跨空間結構(如網(wǎng)架結構、網(wǎng)殼結構等)在設計使用年限內(nèi),除長期受自重等恒荷載的作用外,還承受環(huán)境侵蝕、爆炸、地震和沖擊等作用,造成結構構件的疲勞積累、抗力衰減和材料老化等問題,使結構的實際剛度退化,當損傷積累到一定程度就有可能造成結構整體破壞,歷史上曾經(jīng)發(fā)生過許多大跨空間結構倒塌的事故。因此,為防止結構倒塌事故的發(fā)生,避免發(fā)生重大的安全事故和經(jīng)濟損傷,對大跨空間結構進行定期的檢測十分必要。 鑒于以上原因,本文主要作了以下研究工作: 1)利用有限元軟件ANSYS對鋼懸臂梁結構進行損傷分析。首先采用瞬態(tài)激勵法提取有用信息,構造損傷參數(shù)(單元應變模態(tài)差和單元模態(tài)應變能變化率),然后選取小波函數(shù),對損傷參數(shù)進行小波變換,最后進行結構損傷位置判定。為了驗證數(shù)值模擬的有效性,本文利用實驗室儀器設備,對鋼懸臂梁實物進行了動力模態(tài)測試,將實際實驗數(shù)據(jù)與數(shù)值模擬結果進行對比,進而說明數(shù)值模擬的有效性。 2)由于在實際檢測中采集的信號往往夾雜噪聲信號,為了獲得更好的損傷檢測信號,本文采用小波閾值和MATLAB軟件相結合的方法進行信號消噪的模擬研究,將消噪方法應用到實驗采集信號中,還原原始信號,進行結構損傷識別。 3)利用有限元軟件ANSYS對正放四角錐網(wǎng)架結構進行損傷模擬分析。首先選取最優(yōu)激勵位置,應用單點瞬態(tài)激勵進行完好結構和損傷結構的數(shù)值模擬,然后采集模擬信號,以單元模態(tài)應變能變化率作為損傷參數(shù),最后對損傷參數(shù)進行小波變換,進而進行結構損傷位置判定。
[Abstract]:In recent years, with the rapid development of economy, the construction technology has been improved, and a large number of large-scale and novel long-span spatial structures (such as gymnasium, terminal building, exhibition center, etc.) have been built. Because large span spatial structures are often crowded with people and some places are equipped with important facilities, once the structure is damaged, the damage will cause serious casualties. Large span space structures (such as latticed structures, latticed shell structures, etc.) are subjected to environmental erosion, explosion, earthquake and shock, in addition to being subjected to constant loads such as self-weight for a long time in their design life, resulting in the fatigue accumulation of structural members. The problems of resistance attenuation and material aging make the actual stiffness of the structure degenerate. When the damage accumulates to a certain extent it is possible to cause the overall damage of the structure. Many accidents have occurred in the history of collapse of the long-span space structure. Therefore, in order to prevent the collapse of structures and avoid the occurrence of major safety accidents and economic damage, it is necessary to carry out periodic detection of long-span space structures. In view of the above reasons, the main work of this paper is as follows: 1) the damage analysis of steel cantilever structure is carried out by using finite element software ANSYS. First, the useful information is extracted by transient excitation method, and the damage parameters (strain mode difference of element and strain energy rate of element mode) are constructed, then wavelet function is selected to transform the damage parameters, and finally the damage location of the structure is determined. In order to verify the validity of numerical simulation, the dynamic modal test of steel cantilever beam is carried out by means of laboratory instruments, and the actual experimental data are compared with the results of numerical simulation. 2) because the signals collected in the actual detection are often mixed with noise signals, in order to obtain better damage detection signals, In this paper, the method of combining wavelet threshold with MATLAB software is used to simulate the signal de-noising, and the method of de-noising is applied to the experimental acquisition signal to restore the original signal. 3) the damage simulation analysis of the forward quadrangle truss structure is carried out by using the finite element software ANSYS. At first, the optimal excitation position is selected, and the numerical simulation of intact structure and damaged structure is carried out by single point transient excitation. Then the simulation signals are collected, and the strain energy change rate of element mode is taken as the damage parameter. Finally, the damage parameters are transformed by wavelet transform. Then the damage location of the structure is determined.
【學位授予單位】：河北科技大學
【學位級別】：碩士
【學位授予年份】：2011
【分類號】：TU356
本文編號：2170563
[Abstract]:In recent years, with the rapid development of economy, the construction technology has been improved, and a large number of large-scale and novel long-span spatial structures (such as gymnasium, terminal building, exhibition center, etc.) have been built. Because large span spatial structures are often crowded with people and some places are equipped with important facilities, once the structure is damaged, the damage will cause serious casualties. Large span space structures (such as latticed structures, latticed shell structures, etc.) are subjected to environmental erosion, explosion, earthquake and shock, in addition to being subjected to constant loads such as self-weight for a long time in their design life, resulting in the fatigue accumulation of structural members. The problems of resistance attenuation and material aging make the actual stiffness of the structure degenerate. When the damage accumulates to a certain extent it is possible to cause the overall damage of the structure. Many accidents have occurred in the history of collapse of the long-span space structure. Therefore, in order to prevent the collapse of structures and avoid the occurrence of major safety accidents and economic damage, it is necessary to carry out periodic detection of long-span space structures. In view of the above reasons, the main work of this paper is as follows: 1) the damage analysis of steel cantilever structure is carried out by using finite element software ANSYS. First, the useful information is extracted by transient excitation method, and the damage parameters (strain mode difference of element and strain energy rate of element mode) are constructed, then wavelet function is selected to transform the damage parameters, and finally the damage location of the structure is determined. In order to verify the validity of numerical simulation, the dynamic modal test of steel cantilever beam is carried out by means of laboratory instruments, and the actual experimental data are compared with the results of numerical simulation. 2) because the signals collected in the actual detection are often mixed with noise signals, in order to obtain better damage detection signals, In this paper, the method of combining wavelet threshold with MATLAB software is used to simulate the signal de-noising, and the method of de-noising is applied to the experimental acquisition signal to restore the original signal. 3) the damage simulation analysis of the forward quadrangle truss structure is carried out by using the finite element software ANSYS. At first, the optimal excitation position is selected, and the numerical simulation of intact structure and damaged structure is carried out by single point transient excitation. Then the simulation signals are collected, and the strain energy change rate of element mode is taken as the damage parameter. Finally, the damage parameters are transformed by wavelet transform. Then the damage location of the structure is determined.
【學位授予單位】：河北科技大學
【學位級別】：碩士
【學位授予年份】：2011
【分類號】：TU356
【引證文獻】
相關碩士學位論文 前2條
1 邵長海;基于小波包能量—神經(jīng)網(wǎng)絡的四角錐網(wǎng)架損傷檢測方法研究[D];河北科技大學;2012年
2 李超;網(wǎng)架結構焊接空心球節(jié)點損傷檢測研究[D];河北科技大學;2012年
，本文編號：2170563
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