本文關(guān)鍵詞： 計算長度系數(shù) 二階位移法 軸力面積比法 臨界力重分布法 撓度法　出處：《昆明理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：由于鋼材的高強(qiáng),鋼框架可以做的相對細(xì)柔,這樣就使得結(jié)構(gòu)的穩(wěn)定問題變得突出。由于穩(wěn)定問題屬于二階問題,即需要考慮變形后的平衡,而傳統(tǒng)的。一階強(qiáng)度問題則只考慮變形前的平衡,因此穩(wěn)定問題比一階強(qiáng)度問題復(fù)雜,屬于幾何非線性。穩(wěn)定問題的核心是求解桿件或結(jié)構(gòu)的穩(wěn)定承載力(即臨界力)。求解單個桿件臨界力并不困難,但要求解整個結(jié)構(gòu)的臨界力就不容易了。在現(xiàn)行的《鋼結(jié)構(gòu)設(shè)計規(guī)范》(GB50017-2003)中雖有求解框架計算長度系數(shù)的表格(見附錄D),但該表格隱含了一些假設(shè),使其只能用于規(guī)則框架(各柱軸力相同),而對于不規(guī)則框架(各柱軸力不同)則不再適用了。針對這一現(xiàn)狀本論文擬從兩層框架入手,推導(dǎo)框架整體穩(wěn)定的臨界方程(超越方程)進(jìn)而求解,經(jīng)過幾千次的求解之后,得到了大量的數(shù)據(jù),制成了兩個框架柱計算長度系數(shù)的諾模圖,用這些諾模圖可快速的計算出柱子的計算長度系數(shù)。由于推導(dǎo)和求解是從框架整體失穩(wěn)出發(fā)的,計算得到的各柱的臨界力完全滿足同時失穩(wěn)的條件。本論文最有價值的成果是表4.2和表4.3中的諾模圖,這些諾模圖的正確性和可靠性是經(jīng)過了有限元計算的驗證,且計算精度很高,是快速計算不規(guī)則框架柱的臨界力很好的工具,面對《鋼結(jié)構(gòu)設(shè)計規(guī)范》目前還沒有該方面的計算表格,也算是一種補(bǔ)充。由于是整體穩(wěn)定求解,未知量的數(shù)目隨著層數(shù)的增加而增加,要得到最終的臨界方程難度增大,所以目前僅做到了兩層單跨的框架,但也可用于兩層多跨框架,只需計入多跨框架梁的剛度即可。本論文也探索了求解臨界力的新的近似方法,如軸力面積比法(第5章)、臨界力重分布法(第6章)、撓度法(第7章)等。并獲得了一些成果。
[Abstract]:Because of the high strength of steel, the steel frame can be relatively fine and flexible, so the stability problem of the structure becomes prominent. Because the stability problem belongs to the second order problem, it is necessary to consider the balance after deformation. However, the traditional first order strength problem only considers the balance before deformation, so the stability problem is more complicated than the first order strength problem. The core of the stability problem is to solve the stable bearing capacity of the member or structure (i.e. critical force). It is not difficult to solve the critical force of a single member. However, it is not easy to solve the critical force of the whole structure. In the current Code for Design of Steel structures (GB50017-2003), there is a table for calculating the calculated length coefficient of the frame (see Appendix D). However, the table contains some assumptions that can only be used in a regular frame (the axial force of each column is the same). But it is no longer applicable to irregular frames (different axial forces of columns). In view of this situation, the critical equation (transcendental equation) of global stability of frame is deduced and solved in this paper. After thousands of solutions, a large number of data are obtained, and two frame columns with calculated length coefficients are made into a Norm diagram. The calculated length coefficients of the columns can be calculated quickly by using these Norm diagrams, because the derivation and solution are based on the overall instability of the frame. The calculated critical forces of each column completely satisfy the condition of simultaneous instability. The most valuable results of this paper are the Norm graphs in Table 4.2 and Table 4.3. The correctness and reliability of these Norm diagrams are verified by the finite element calculation, and the calculation accuracy is very high. It is a good tool to calculate the critical force of irregular frame columns quickly. In the face of the steel structure design code, there is no calculation table for this aspect, which is a supplement. Because of the overall stability of the solution, the number of unknown quantities increases with the increase of the number of layers. To obtain the final critical equation is more difficult, so at present only a two-story single-span frame, but also can be used for two-story multi-span frame. The stiffness of multi-span frame beam can only be taken into account. In this paper, a new approximate method to solve the critical force, such as the axial force area ratio method (Chapter 5, critical force redistribution method), is also explored in this paper. Deflection method (Chapter 7) and some results are obtained.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU391

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本文編號：1472691