本文選題：鋼桁架橋 + 箱包炸彈�。� 參考：《西南科技大學(xué)》2017年碩士論文

【摘要】：本文采用數(shù)值模擬方法,系統(tǒng)深入的研究了鋼桁架橋梁在箱包炸彈作用下的動(dòng)力響應(yīng)、破壞模式,并基于承載能力對(duì)爆損橋梁的生存能力進(jìn)行了快速評(píng)估。其研究成果能夠?yàn)殇撹旒軜蛄旱目贡辣O(shè)計(jì)以及后續(xù)的修復(fù)加固提供相關(guān)參考和依據(jù)。本文的主要成果如下:(1)箱包炸彈作用下,鋼桁架橋梁的耗能方式為桁架梁與橋面板的塑性變形,橋面板和鋼桁架梁塑性變形耗能之和約占總能量的90%左右。對(duì)于鋼桁架橋梁,加強(qiáng)桁架梁與增強(qiáng)節(jié)點(diǎn)的連接,提高橋面板和鋼桁架梁的塑性變形能力,將有助于提高橋梁結(jié)構(gòu)在爆炸載荷作用下的生存能力。(2)在箱包炸彈作用下,鋼桁架橋梁的破壞模式可歸納為3種:模式Ⅰ,橋面板發(fā)生塑性變形,鋼桁架梁發(fā)生塑性變形。模式Ⅱ,橋面板發(fā)生塑性變形,鋼桁架梁斷裂損毀;模式Ⅲ,橋面板開(kāi)裂破口,鋼桁梁斷裂損毀。藥量、炸點(diǎn)位置均能影響結(jié)構(gòu)的破壞程度、破壞模式,相對(duì)于炸藥當(dāng)量,炸點(diǎn)位置的改變對(duì)結(jié)構(gòu)的破壞程度、破壞模式的影響更加敏感。(3)基于承載能力提出了一種生存能力評(píng)估方法,該方法采用LS-DYNA重啟動(dòng)功能,以設(shè)計(jì)荷載為控制荷載對(duì)爆損橋梁加載,獲得爆損橋梁各控制截面力學(xué)參數(shù)。重點(diǎn)考校分析關(guān)鍵力學(xué)參數(shù):應(yīng)力、撓度、沖擊系數(shù)是否超過(guò)規(guī)范規(guī)定的限值,從強(qiáng)度、剛度、穩(wěn)定性3方面綜合判斷橋梁的生存能力是否滿足現(xiàn)有荷載等級(jí)要求。(4)對(duì)發(fā)生破壞模式Ⅰ的爆損橋梁進(jìn)行了生存能力評(píng)估,結(jié)果表明:工況1、工況2、工況5、工況9爆炸荷載作用下,橋梁的生存能力滿足現(xiàn)有荷載等級(jí)的要求;工況3作用下,施加荷載后橋梁的豎向撓度超過(guò)限制,其生存能力不滿足現(xiàn)有荷載等級(jí)的要求;工況4作用下,施加荷載后橋梁主桁的3根腹桿發(fā)生斷裂破壞,結(jié)構(gòu)喪失承載能力,不滿足現(xiàn)有荷載等級(jí),應(yīng)進(jìn)行修復(fù)加固。
[Abstract]:In this paper, the dynamic response and failure mode of steel truss bridges under the action of box and bag bombs are studied systematically and deeply by using numerical simulation method, and the survivability of damaged bridges is evaluated quickly based on load-carrying capacity. The research results can provide reference and basis for anti-explosion design and subsequent repair and reinforcement of steel truss bridge. The main results of this paper are as follows: 1) under the action of box bomb, the energy dissipation of steel truss bridge is the plastic deformation of truss beam and deck slab, and the sum of plastic deformation energy consumption of bridge deck plate and steel truss beam is about 90% of the total energy consumption. For steel truss bridges, strengthening the connection between truss beams and reinforced joints and improving the plastic deformation capacity of deck and steel truss beams will help to improve the survivability of bridge structures under explosive loading. The failure modes of steel truss bridges can be divided into three types: mode 鈪，

本文編號(hào)：1875939