【摘要】：伴隨我國的電力建設(shè)和經(jīng)濟(jì)發(fā)展,越來越多的輸電塔會途經(jīng)地基易變形(煤礦開采、凍軟土)和極限天氣(大風(fēng)、冰雪災(zāi)害)易發(fā)生地區(qū),此類地區(qū)外部環(huán)境因素多變,極易引發(fā)輸電塔變形甚至損毀。此外,電網(wǎng)電壓等級的提高會使輸電線路的塔架高度和檔距也隨之增加,而大跨越輸電塔對動載荷的變化更加敏感,因此實(shí)際應(yīng)用中對于動態(tài)響應(yīng)的預(yù)測需求也日益迫切。作為由型鋼、鋼管等桿件連接而成的格構(gòu)式結(jié)構(gòu),輸電塔的搭建多通過螺栓偏心連接而成。由于螺栓與螺孔之間存在配合間隙,受較大剪切力時,桿件連接處易錯動,發(fā)生螺栓滑移現(xiàn)象。長期研究表明,在承受較大外力載荷時輸電塔的實(shí)際變形與傳統(tǒng)有限元軟件分析結(jié)果嚴(yán)重不符,極限承載力的估測判定也尚待考察。動態(tài)方面,對輸電塔固有頻率的預(yù)測也與實(shí)際有較大偏差。分析其原因,即在有限元建模時對螺栓連接的處理過于簡化,剛接或鉸接都會使得連接剛度過大,模擬不準(zhǔn)確。課題組在之前的研究中,已完成了對典型螺栓連接的軸向拉伸測試,以及對11OkV單回路直線貓頭型輸電塔的足尺寸試驗(yàn),包含單根塔腿非均勻沉降工況和固定塔腿的動態(tài)測量。在此基礎(chǔ)上,本文利用ANSYS軟件,先后將塔身斜撐桿件、塔腿主材、塔頭桿件的螺栓連接考慮到有限元模型中。針對單根塔腿非均勻沉降工況下的輸電塔,重點(diǎn)考察了螺栓非線性滑移曲線的微觀滑移剛度和宏觀滑移長度兩個重要參數(shù)對模擬結(jié)果的影響,同時針對各部位螺栓連接對輸電塔動、靜態(tài)力學(xué)特性的影響進(jìn)行了詳細(xì)研究。工程中已發(fā)現(xiàn),預(yù)測已經(jīng)失效的輸電塔在實(shí)際中常常運(yùn)行良好。本文就此現(xiàn)象考察了傳統(tǒng)模型和考慮螺栓滑移模型在幾種非均勻沉降工況下的模擬差異。此外,在輸電線路設(shè)計(jì)過程中為保證安全運(yùn)行需對沿線的氣象環(huán)境進(jìn)行全面的了解以及精確的模擬驗(yàn)算。本文還考察了四種最大工作荷載工況下,考慮螺栓連接對模擬結(jié)果的影響,進(jìn)一步驗(yàn)證了建模時引入各部位螺栓連接對精確預(yù)測輸電線路的力學(xué)響應(yīng)具有重要意義。本文詳細(xì)分析了螺栓連接對輸電塔力學(xué)特性的影響,基于考慮螺栓連接的改進(jìn)模型,可以對輸電塔抗變形、抗振動設(shè)計(jì)以及安全性評估和治理提出更合理化的建議,也為更加復(fù)雜的塔線體系的研究奠定基礎(chǔ)。
[Abstract]:With the development of electric power construction and economy in China, more and more transmission towers will pass through the areas where the foundation is easy to deform (coal mining, frozen soft soil) and extreme weather (gale, ice and snow disasters) are easy to occur. External environmental factors in such areas are changeable, which will easily lead to the deformation and even damage of transmission towers. With the increase of tower height and span, the long-span transmission tower is more sensitive to the change of dynamic load, so it is more and more urgent to predict the dynamic response in practical application. The long-term research shows that the actual deformation of the transmission tower is seriously inconsistent with the results of the traditional finite element software analysis, and the estimation of the ultimate bearing capacity is still to be investigated. The reason is that the treatment of bolted connection is too simplified in finite element modeling, and rigid or hinged connection will lead to excessive stiffness and inaccurate simulation. The full-scale test of the head-type transmission tower includes the non-uniform settlement of the single leg and the dynamic measurement of the fixed leg. On this basis, the bolt connection of the oblique strut, the main material of the leg and the head member of the tower is considered in the finite element model by using ANSYS software. The influence of the two important parameters of the nonlinear slip curve of bolts on the simulation results is investigated, including the micro-slip stiffness and the macro-slip length. At the same time, the influence of the bolt connection on the dynamic and static mechanical characteristics of the transmission tower is studied in detail. Good. This paper investigates the difference between the traditional model and the bolt slip model under several non-uniform settlement conditions. In addition, in order to ensure the safe operation of the transmission line, it is necessary to have a comprehensive understanding of the meteorological environment along the line and accurate simulation checking. In this paper, the influence of bolt connection on the mechanical characteristics of transmission tower is analyzed in detail, and the improved model considering bolt connection can resist the deformation of transmission tower. More reasonable suggestions for anti-vibration design, safety evaluation and treatment are put forward, which lays a foundation for the study of more complex tower-line system.
【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM75

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本文編號：2207699