【摘要】：近些年來,我國在經(jīng)濟(jì)迅速發(fā)展的推動(dòng)下,建筑技術(shù)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(jié)構(gòu)(如體育館、航站樓、展覽中心等)。由于大跨度空間結(jié)構(gòu)往往人群聚集,而且有些場(chǎng)所配置重要設(shè)施,因此結(jié)構(gòu)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(jié)構(gòu)(如網(wǎng)架結(jié)構(gòu)、網(wǎng)殼結(jié)構(gòu)等)在設(shè)計(jì)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(jié)構(gòu)構(gòu)件的疲勞積累、抗力衰減和材料老化等問題,使結(jié)構(gòu)的實(shí)際剛度退化,當(dāng)損傷積累到一定程度就有可能造成結(jié)構(gòu)整體破壞,歷史上曾經(jīng)發(fā)生過許多大跨空間結(jié)構(gòu)倒塌的事故。因此,為防止結(jié)構(gòu)倒塌事故的發(fā)生,避免發(fā)生重大的安全事故和經(jīng)濟(jì)損傷,對(duì)大跨空間結(jié)構(gòu)進(jìn)行定期的檢測(cè)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(duì)鋼懸臂梁結(jié)構(gòu)進(jìn)行損傷分析。首先采用瞬態(tài)激勵(lì)法提取有用信息,構(gòu)造損傷參數(shù)(單元應(yīng)變模態(tài)差和單元模態(tài)應(yīng)變能變化率),然后選取小波函數(shù),對(duì)損傷參數(shù)進(jìn)行小波變換,最后進(jìn)行結(jié)構(gòu)損傷位置判定。為了驗(yàn)證數(shù)值模擬的有效性,本文利用實(shí)驗(yàn)室儀器設(shè)備,對(duì)鋼懸臂梁實(shí)物進(jìn)行了動(dòng)力模態(tài)測(cè)試,將實(shí)際實(shí)驗(yàn)數(shù)據(jù)與數(shù)值模擬結(jié)果進(jìn)行對(duì)比,進(jìn)而說明數(shù)值模擬的有效性。 2)由于在實(shí)際檢測(cè)中采集的信號(hào)往往夾雜噪聲信號(hào),為了獲得更好的損傷檢測(cè)信號(hào),本文采用小波閾值和MATLAB軟件相結(jié)合的方法進(jìn)行信號(hào)消噪的模擬研究,將消噪方法應(yīng)用到實(shí)驗(yàn)采集信號(hào)中,還原原始信號(hào),進(jìn)行結(jié)構(gòu)損傷識(shí)別。 3)利用有限元軟件ANSYS對(duì)正放四角錐網(wǎng)架結(jié)構(gòu)進(jìn)行損傷模擬分析。首先選取最優(yōu)激勵(lì)位置,應(yīng)用單點(diǎn)瞬態(tài)激勵(lì)進(jìn)行完好結(jié)構(gòu)和損傷結(jié)構(gòu)的數(shù)值模擬,然后采集模擬信號(hào),以單元模態(tài)應(yīng)變能變化率作為損傷參數(shù),最后對(duì)損傷參數(shù)進(jìn)行小波變換,進(jìn)而進(jìn)行結(jié)構(gòu)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(xué)位授予單位】：河北科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2011
【分類號(hào)】：TU356

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前2條

1 邵長海;基于小波包能量—神經(jīng)網(wǎng)絡(luò)的四角錐網(wǎng)架損傷檢測(cè)方法研究[D];河北科技大學(xué);2012年

2 李超;網(wǎng)架結(jié)構(gòu)焊接空心球節(jié)點(diǎn)損傷檢測(cè)研究[D];河北科技大學(xué);2012年

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本文編號(hào)：2170563