本文關(guān)鍵詞：基于貝葉斯推斷和動(dòng)力測(cè)試的既有砌體結(jié)構(gòu)性能分析　出處：《上海理工大學(xué)》2014年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 砌體結(jié)構(gòu) 貝葉斯推斷 動(dòng)力測(cè)試 基本頻率 等效彈性模量 有限元模擬

【摘要】：由于砌體材料具有良好的物理性能,且施工方法簡(jiǎn)便,造價(jià)低廉,所以至今仍是我國(guó)主導(dǎo)的建筑材料。砌體結(jié)構(gòu)在我國(guó)有著悠久的歷史,歲月的沉淀給這些已有的建筑結(jié)構(gòu)帶來(lái)了潛在的威脅,所以對(duì)于這些既有砌體結(jié)構(gòu)的性能檢測(cè)也變得尤為重要。雖然原位測(cè)試及鉆芯法等現(xiàn)場(chǎng)測(cè)試方法是當(dāng)前主要的檢測(cè)方法,然而,這些方法會(huì)對(duì)結(jié)構(gòu)造成新的損傷,所以這些方法仍然存在著一定的缺陷,并不完善。因此,基于無(wú)損的動(dòng)力測(cè)試方法的結(jié)構(gòu)性能檢測(cè)方法受到了越來(lái)越多的關(guān)注。頻率是既有砌體結(jié)構(gòu)安全性的重要指標(biāo),由于損傷情況、結(jié)構(gòu)形式以及測(cè)試方法等不確定因素的影響,導(dǎo)致其現(xiàn)場(chǎng)實(shí)測(cè)結(jié)果數(shù)據(jù)量有限且非常離散,難以確定合理的估計(jì)值。傳統(tǒng)的回歸分析方法完全依賴(lài)于實(shí)測(cè)樣本,如果實(shí)測(cè)樣本離散,也會(huì)造成結(jié)果判斷的嚴(yán)重偏差。為解決這一問(wèn)題,嘗試采用貝葉斯推斷方法,通過(guò)馬爾科夫蒙特卡洛(Markov Chain Monte Carlo,MCMC)抽樣,結(jié)合先驗(yàn)信息,將結(jié)構(gòu)頻率作為未確知量,形式上借助數(shù)理統(tǒng)計(jì)的方法來(lái)處理。首先通過(guò)三維數(shù)值模擬確定結(jié)構(gòu)動(dòng)力測(cè)試的采樣頻率以及加速度傳感器的布置方案,然后分別采用環(huán)境激勵(lì)與人工激勵(lì)方法,獲得結(jié)構(gòu)的加速度時(shí)程曲線(xiàn),通過(guò)快速傅里葉變換(Fast Fourier Transform,FFT)獲取結(jié)構(gòu)基本頻率的樣本數(shù)據(jù)。運(yùn)用貝葉斯推斷方法,通過(guò)Metropolis-Hasting(MH)抽樣,結(jié)合對(duì)基本頻率的先驗(yàn)判斷,構(gòu)建基本頻率的后驗(yàn)概率密度模型,從而確定結(jié)構(gòu)基本頻率的估計(jì)值。通過(guò)有限元模型,擬合結(jié)構(gòu)頻率與彈性模量之間的關(guān)系式,反算出結(jié)構(gòu)等效彈性模量的估計(jì)值。結(jié)果表明,以上方法在實(shí)測(cè)樣本量少、噪音影響較大的情況下具有很好的魯棒性,能夠較快收斂于穩(wěn)定、合理的后驗(yàn)概率密度模型,為推斷結(jié)構(gòu)彈性模量提供可靠的基礎(chǔ)。針對(duì)某既有砌體結(jié)構(gòu),對(duì)其進(jìn)行動(dòng)力測(cè)試,結(jié)合先驗(yàn)判斷,獲取其頻率的后驗(yàn)概率密度模型,根據(jù)有限元模型反算結(jié)構(gòu)等效彈性模量估計(jì)值,驗(yàn)證本文所提方法的工程應(yīng)用。說(shuō)明該方法可為砌體結(jié)構(gòu)性能的長(zhǎng)期監(jiān)測(cè)提供一種經(jīng)濟(jì)、有效的手段。
[Abstract]:Masonry materials have good physical properties, simple construction methods and low cost, so they are still the leading building materials in China. Masonry structure has a long history in China. The sedimentation of years has brought a potential threat to these existing building structures. Therefore, for these existing masonry structure performance testing has become particularly important. Although in-situ testing and core drilling methods are the main testing methods, however. These methods will cause new damage to the structure, so these methods still have some defects and are not perfect. More and more attention has been paid to the structural performance testing method based on the non-destructive dynamic testing method. Frequency is an important index of the safety of existing masonry structure due to damage. Due to the influence of uncertain factors, such as structure form and test method, the field measured results are limited and discrete, so it is difficult to determine the reasonable estimation value. The traditional regression analysis method is completely dependent on the measured samples. In order to solve this problem, Bayesian inference method is used to solve this problem. The structural frequency is taken as an unascertained quantity through Markov Chain Monte Monte MCMC sampling and a priori information. Firstly, the sampling frequency of structural dynamic test and the layout of acceleration sensor are determined by three-dimensional numerical simulation. Then the acceleration time history curve of the structure is obtained by using the environmental excitation method and the artificial excitation method, and the fast Fourier Transform is obtained by the fast Fourier transform. The sample data of the basic frequency of the structure are obtained by FFT.The Bayesian inference method is used to sample the basic frequency through Metropolis-HastingMH sampling and the prior judgment of the basic frequency is combined. The posteriori probability density model of the basic frequency is constructed to determine the estimated value of the basic frequency of the structure. The finite element model is used to fit the relationship between the structural frequency and the elastic modulus. The results show that the proposed method is robust in the case of small sample size and large noise effect, and can converge to stability quickly. A reasonable posteriori probability density model provides a reliable basis for inferring the elastic modulus of a structure. For an existing masonry structure, the dynamic test is carried out and the posterior probability density model of its frequency is obtained by combining the prior judgment. The engineering application of the method proposed in this paper is verified by the inverse calculation of the equivalent elastic modulus of the structure based on the finite element model. It is shown that the method can provide an economic and effective means for the long-term monitoring of masonry structure performance.
【學(xué)位授予單位】：上海理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TU364

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本文編號(hào)：1430160