本文選題：分形理論 + 關(guān)聯(lián)維數(shù)�。� 參考：《河北科技大學(xué)》2014年碩士論文

【摘要】：近些年,鋼結(jié)構(gòu)被廣泛用于大型工業(yè)、民業(yè)以及公共建筑設(shè)施中,但隨著結(jié)構(gòu)使用時間的延長,超負(fù)荷使用等問題的出現(xiàn),使其出現(xiàn)損傷、失效等相關(guān)危害越來越多。因此,鋼結(jié)構(gòu)損傷檢測不容忽視,尋找高效準(zhǔn)確的檢測方法也更受到研究人員的關(guān)注。針對鋼結(jié)構(gòu)獨特結(jié)構(gòu)形式,本文進(jìn)行了以下幾方面研究:1)本文介紹了分形理論、關(guān)聯(lián)維數(shù)在國內(nèi)外近些年的發(fā)展?fàn)顩r,對現(xiàn)階段的理論研究進(jìn)行了分類比較;引入了相空間重構(gòu)、嵌入維數(shù)、時間延遲、無標(biāo)度區(qū)等重要參變量概念,以一鋼桁架為例,提出了基于分形理論關(guān)聯(lián)維數(shù)的鋼桁架結(jié)構(gòu)的損傷檢測方法。2)利用ANSYS軟件建模,分別建立完好工況、單損傷工況、多損傷工況的桁架模型,并對結(jié)構(gòu)進(jìn)行瞬態(tài)分析,采集各工況下結(jié)構(gòu)節(jié)點加速度響應(yīng)信號。運用分形理論對結(jié)構(gòu)損傷前后各節(jié)點響應(yīng)信號直接進(jìn)行關(guān)聯(lián)維數(shù)處理,擬合了各節(jié)點ln(r)-(Cr)圖形,并由此得出嵌入維數(shù)m與關(guān)聯(lián)維數(shù)D的關(guān)系,最后對不同工況下節(jié)點關(guān)聯(lián)維數(shù)差值絕對值△D進(jìn)行分析比較,利用各工況節(jié)點△D的大小,達(dá)到確定桿件損傷位置和初步判別損傷程度的目的。3)考慮到實際檢測過程中外界環(huán)境的影響,本文以環(huán)境噪聲為例,模擬了上述桁架模型在實際環(huán)境中應(yīng)用該方法進(jìn)行損傷檢測的情況。以隨機函數(shù)形式,對桁架節(jié)點加速度響應(yīng)信號施加15%隨機水平噪聲,對與噪聲信號疊加后的節(jié)點振動信號重新進(jìn)行關(guān)聯(lián)維數(shù)處理,得出各節(jié)點新的關(guān)聯(lián)維數(shù)△D值大小,與上述無噪聲情況進(jìn)行比較分析,確定該方法在噪聲環(huán)境下進(jìn)行鋼桁架結(jié)構(gòu)損傷檢測時的抗噪聲能力及穩(wěn)定性。
[Abstract]:In recent years, steel structure has been widely used in large-scale industry, civilian industry and public building facilities. However, with the extension of service time of the structure and the emergence of overload problems, the damage and failure of steel structure are becoming more and more. Therefore, the damage detection of steel structures can not be ignored, and the search for efficient and accurate detection methods has been paid more attention by researchers. Aiming at the unique structure form of steel structure, this paper studies the following aspects: 1) this paper introduces the fractal theory, the development of correlation dimension at home and abroad in recent years, and compares the current theoretical research. The concepts of phase space reconstruction, embedding dimension, time delay and scale-free zone are introduced. Taking a steel truss as an example, the damage detection method of steel truss structure based on correlation dimension of fractal theory is proposed. The truss models of intact condition, single damage condition and multiple damage condition are established, and the transient analysis of the structure is carried out, and the acceleration response signals of the structure node are collected under each working condition. Using fractal theory, the correlation dimension of the response signals of each node before and after structural damage is directly processed, and the relationship between the embedded dimension m and the correlation dimension D is obtained. Finally, the absolute value D of the node correlation dimension difference under different working conditions is analyzed and compared. In order to determine the damage location and judge the damage degree of the member. 3) considering the influence of the outside environment in the actual detection process, this paper takes the environmental noise as an example. The application of the method to the damage detection of the truss model is simulated. In the form of random function, 15% random horizontal noise is applied to the acceleration response signal of the truss node, and the correlation dimension of the joint vibration signal superimposed with the noise signal is processed again, and the new correlation dimension D value of each node is obtained. Compared with the above noise-free condition, the anti-noise ability and stability of the method are determined when the damage detection of steel truss structures is carried out under the noise environment.
【學(xué)位授予單位】：河北科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU317;TU391

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本文編號：1838399