發(fā)布時間：2018-04-29 18:26

  本文選題：壓電阻抗 + 木試件�。� 參考：《華中科技大學》2015年碩士論文

【摘要】：壓電阻抗技術近年來被廣泛應用于土木工程結構損傷識別與健康監(jiān)測領域,包括鋼結構、混凝土結構以及鋁合金結構的損傷檢測。但是,關于將其應用于木結構的損傷檢測方面的研究比較少。本文在壓電阻抗技術已有的研究成果上,通過木試件損傷檢測試驗研究,探索了將壓電阻抗技術應用于木結構損傷識別的可行性。本文的試驗材料包括針葉類代表木材芬蘭松和闊葉類代表木材巴勞木,損傷類型包括橫紋損傷、順紋損傷以及孔洞損傷。通過分別測量健康與損傷狀態(tài)下試件的導納曲線,研究壓電阻抗技術對于木結構損傷識別的可行性。為定性判斷損傷程度,除使用常規(guī)的相關系數(shù)(CC)、均方根偏差(RMSD)指標以外,還引入了馬氏距離(Mahalanobis Distance)。由于馬氏距離指標在本試驗數(shù)據(jù)處理中存在計算結果不可靠等問題,本文對馬氏距離進行了基于主成分分析的合理改進,建立了基于改進馬氏距離(Modified Mahalanobis Distance)的損傷程度評價指標。根據(jù)本文研究內容,可得出以下結論:1、壓電阻抗技術對芬蘭松的損傷比巴勞木更為敏感。通過觀察發(fā)現(xiàn),芬蘭松損傷檢測試驗中所有頻率段的CC和RMSD均可有效反映損傷變化,而巴勞木損傷檢測試驗中存在少量工況的部分頻率段不能反映損傷變化。2、不同損傷類型的損傷敏感頻率段不一樣。分析CC、RMSD指標可知,橫紋、順紋損傷在30kHz-50k Hz的損傷指標變化更顯著;而孔洞損傷在30kHz-50kHz和150kHz-500kHz的指標變化更為顯著。3、改進馬氏距離融合了多頻率段損傷信息,比CC和RMSD指標包含了更多的統(tǒng)計信息,可以從整體上衡量各工況之間的差異,為基于壓電阻抗技術的木結構損傷檢測提供更可靠的評價。綜上所述,將壓電阻抗技術應用于木試件損傷檢測是可行的。
[Abstract]:Piezoelectric impedance technology has been widely used in the field of damage identification and health monitoring of civil engineering structures in recent years, including steel structure, concrete structure and aluminum alloy structure damage detection. However, there is little research on the application of it to the damage detection of wood structures. In this paper, based on the research results of piezoelectric impedance technology, the feasibility of applying piezoelectric impedance technology to the damage identification of wood structures is explored by means of the damage detection test of wood specimens. The experimental materials in this paper include coniferous pine and broad-leaved wood, and the damage types include transverse damage, collateral damage and hole damage. The feasibility of piezoelectric impedance technique for wood structure damage identification was studied by measuring the admittance curves of the specimens under the condition of health and injury respectively. In order to judge the degree of damage qualitatively, Mahalanobis distance was introduced in addition to the conventional correlation coefficient (CCN) and root mean square deviation (RMSD). Because the Mahalanobis distance index is not reliable in the data processing of this experiment, this paper improves the Markov distance reasonably based on principal component analysis, and establishes the damage degree evaluation index based on the improved Markov distance modified Mahalanobis distance. According to the present study, the following conclusions can be drawn: 1, piezoelectric impedance technique is more sensitive to the damage of Pinus Finland than Baraum. It was found that CC and RMSD of all frequency bands in the damage detection test of Finnish pine could effectively reflect the damage changes. However, in the damage detection test of Baroum, a small number of operating conditions can not reflect the damage change. 2. The damage sensitive frequency of different damage types is different. According to the analysis of RMSD, the damage index of cross stripe and parallel grain is more significant in 30kHz-50k Hz, while the index of hole damage in 30kHz-50kHz and 150kHz-500kHz is more significant. 3. The improved Markov distance fuses multi-frequency damage information. The index of CC and RMSD contains more statistical information, which can measure the difference between different working conditions on the whole, and provide a more reliable evaluation for damage detection of wood structure based on piezoelectric impedance technology. In conclusion, it is feasible to apply piezoelectric impedance technique to the damage detection of wood specimens.
【學位授予單位】：華中科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU317

【引證文獻】

相關碩士學位論文 前1條

1 李陽;采棉機作業(yè)工況監(jiān)測及典型故障診斷研究[D];中國農(nóng)業(yè)機械化科學研究院;2017年

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本文編號：1821067