本文選題：被動柔性防護網(wǎng)結(jié)構(gòu) + 環(huán)形網(wǎng)片��； 參考：《西南交通大學》2017年碩士論文

【摘要】：我國地勢西高東低,地質(zhì)構(gòu)造多樣,隨著近些年的氣候變化,地質(zhì)災害多發(fā),其中崩塌落石因其發(fā)生突然、發(fā)生頻率高、高沖擊動能等,對山區(qū)交通干線、城鎮(zhèn)等構(gòu)成了嚴重的威脅。廣大技術(shù)人員根據(jù)現(xiàn)場實際的崩塌落石發(fā)育特點以及地形地質(zhì)條件積累了大量的實際應用經(jīng)驗,其中被動柔性防護網(wǎng)結(jié)構(gòu)以其施工方便、干擾小、標準化生產(chǎn)、造價低、實用性強等眾多特點在實際工程中被廣泛應用。環(huán)形網(wǎng)片是被動柔性防護網(wǎng)結(jié)構(gòu)的重要組成部分之一,而在實際工程應用中經(jīng)常出現(xiàn)環(huán)形網(wǎng)片被擊穿的破壞現(xiàn)象。本文以環(huán)形網(wǎng)片構(gòu)件為研究對象,通過理論推導、數(shù)值模擬和試驗數(shù)據(jù)對比分析等手段對環(huán)形網(wǎng)片進行了基礎(chǔ)性的研究,本文主要完成了以下工作。(1)以材料與結(jié)構(gòu)的能量吸收方面的相關(guān)理論為基礎(chǔ),理論推導了單個圓環(huán)在二力、四力和六力作用下的理論耗能公式,并與現(xiàn)有的文獻結(jié)果進行了對比分析,證明了本文理論推導的正確性,為環(huán)形網(wǎng)片的耗能研究提供了一定的理論基礎(chǔ)。(2)通過ANSYS/LS-DYNA軟件建立與文獻中同等尺寸、同等邊界條件、同等沖擊過程的環(huán)形網(wǎng)片,分別進行24kJ和45kJ作用下的落石沖擊分析,將得到的數(shù)據(jù)與文獻中的試驗結(jié)果進行對比,證明了文中數(shù)值仿真建模的正確性,為數(shù)值分析環(huán)形網(wǎng)片的動力響應和耗能情況提供了一套合理的建模方法。(3)通過利用試驗數(shù)據(jù)驗證過的建模方法建立3.3m×6.6m的環(huán)形網(wǎng)片。首先,進行三種邊界約束形式下的數(shù)值分析,對比落石沖擊環(huán)形網(wǎng)片的動力響應和各種約束形式下的最大耗能;然后,分析是否考慮落石重力對環(huán)形網(wǎng)片耗能性能的影響,分為三種情況對其進行研究;最后,分析環(huán)形網(wǎng)片在落石不同沖擊角度下的動力響應和耗能情況,根據(jù)沖擊角度的不同,分為五種情況進行研究。(4)通過改變橫、縱向的圓環(huán)數(shù)目建立不同尺寸的環(huán)形網(wǎng)片,分析落石垂直沖擊中間位置時的受荷區(qū)域分布規(guī)律,定量的給出環(huán)形網(wǎng)片的理論耗能計算公式,為基于能量的整體防護結(jié)構(gòu)體系設(shè)計提供一定的理論基礎(chǔ)。
[Abstract]:With the climate change in recent years, geological disasters occur frequently in China, in which the collapse and falling stone occur suddenly, high frequency, high impact kinetic energy, etc., on the main traffic lines in mountainous areas. Towns and cities pose a serious threat. The vast number of technicians have accumulated a great deal of practical application experience according to the development characteristics of collapsing and falling rocks and the topographic and geological conditions. Among them, the passive flexible protective net structure has the advantages of convenient construction, small interference, standardized production and low cost. Many characteristics, such as strong practicability, are widely used in practical engineering. Annular mesh is one of the important parts of passive flexible protective net structure, and the breakdown of annular mesh is often occurred in practical engineering application. In this paper, the annular mesh component is taken as the research object, and the basic research is carried out by means of theoretical derivation, numerical simulation and comparative analysis of experimental data. Based on the theory of energy absorption of materials and structures, the theoretical energy dissipation formulas of a single ring under the action of two, four and six forces are derived. By comparing the results with the existing literatures, it is proved that the theoretical derivation of this paper is correct, which provides a theoretical basis for the study of energy dissipation in annular mesh. (2) the same size and boundary conditions as in the literature are established by using ANSYS/LS-DYNA software. Under the action of 24kJ and 45kJ, the annular mesh of the same impact process is analyzed respectively. The results obtained are compared with the experimental results in the literature, which proves the correctness of the numerical simulation modeling in this paper. A set of reasonable modeling method is provided for the numerical analysis of the dynamic response and energy dissipation of annular mesh. The annular mesh with 3.3m 脳 6.6m is established by using the modeling method verified by the experimental data. Firstly, the numerical analysis of three kinds of boundary constraint forms is carried out to compare the dynamic response and the maximum energy consumption under various constraint forms of the annular mesh, and then, whether to consider the influence of the falling gravity on the energy dissipation performance of the annular mesh is analyzed. Finally, the dynamic response and energy dissipation of annular mesh at different impact angles are analyzed. According to the impact angle, it is divided into five situations. The number of rings in longitudinal direction is used to establish annular mesh with different sizes, and the distribution law of the loading area at the middle position of vertical impact is analyzed, and the theoretical energy consumption formula of the annular mesh is given quantitatively. It provides a theoretical basis for the design of the whole protection structure based on energy.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：U417.1

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