【摘要】：隨著城市與新農(nóng)村建設(shè)不斷向前推進,尤其是國家權(quán)威部門已明確指出,新一輪GDP增長主要來源于農(nóng)村的城鎮(zhèn)化。建筑業(yè)作為城鎮(zhèn)化的主要行業(yè),其結(jié)構(gòu)的形式與構(gòu)造也須不斷地改進和完善以適應(yīng)建筑產(chǎn)業(yè)化的發(fā)展。其中,冷彎薄壁型鋼結(jié)構(gòu)體系作為工業(yè)化輕鋼結(jié)構(gòu)的一個分支倍受矚目,其最顯著的優(yōu)勢是施工周期短,可以提高投資效益,加快資金周轉(zhuǎn)；并且施工場地占用率、建筑垃圾、建筑施工噪音等都大大降低。同時,輕鋼結(jié)構(gòu)建筑所用材料主要是可回收或易降解的材料,既節(jié)能、環(huán)保,又不失美觀、大方,符合現(xiàn)代建筑發(fā)展方向理念。目前,冷彎薄壁型鋼已廣泛地應(yīng)用于低層民用建筑中。其優(yōu)點在于質(zhì)輕,并且隨著制造工藝的進步,屈服強度越來越高,耐久性也越來越好。同時,冷彎薄壁型鋼的施工便捷性也是其它傳統(tǒng)鋼結(jié)構(gòu)無法相比的,這些特點使得冷彎薄壁型鋼在鋼結(jié)構(gòu)住宅產(chǎn)業(yè)化與新農(nóng)村建設(shè)的大背景下,有著巨大的優(yōu)勢和發(fā)展前景。 本文選擇應(yīng)用最廣泛、產(chǎn)業(yè)化程度最高的冷彎薄壁型鋼C型構(gòu)件作為研究對象,認為現(xiàn)有研究對相關(guān)屈曲機理、滯回性能以及適合各類截面的設(shè)計方法還存在一些值得深入的研究點�；诖�,本文對以下內(nèi)容展開了深入研究： (1)借鑒Shanley模型,推導(dǎo)了一維桿件屈曲的全過程,深入分析了一維桿件屈曲機理與影響因素,包括初始缺陷與截面參數(shù)等。在此基礎(chǔ)上,根據(jù)塑性區(qū)域分布不同,將塑性分為理想塑性與分布塑性,并推導(dǎo)了一維桿件塑性分布區(qū)域的表達式,得到了影響塑性分布區(qū)域的影響因子。同時,基于桿件屈曲模型,分析了r(塑性剛度或屈曲后剛度)與桿件屈曲、塑性行為之間的關(guān)系,為后文薄壁構(gòu)件屈曲機理分析作準(zhǔn)備。 (2)對冷彎薄壁C型構(gòu)件進行了試驗研究與數(shù)值模擬,包括：水平循環(huán)荷載作用下的構(gòu)件滯回性能、靜軸力下的屈曲行為與破壞特點,以及靜力和循環(huán)荷載作用下的構(gòu)件組合作用。分別得到了冷彎薄壁型鋼C型構(gòu)件在循環(huán)荷載作用下的恢復(fù)力模型與破壞機理、靜軸力作用下構(gòu)件破壞機理與偏心影響以及組合作用產(chǎn)生的機理,為格構(gòu)機理模型的驗證提供支持。 (3)分析了構(gòu)件在水平循環(huán)荷載和靜軸力作用下的屈曲行為與破壞機理,提出了冷彎薄壁C型構(gòu)件格構(gòu)機理模型,并通過數(shù)值與試驗,驗證了其合理性�；诟駱�(gòu)機理模型,將薄壁構(gòu)件與一維桿件屈曲機理聯(lián)系起來,分析了構(gòu)件初始缺陷與板組效應(yīng)的影響機理,得到了構(gòu)件畸變屈曲半波長計算公式,并與經(jīng)典方法和數(shù)值模擬進行了對比分析。 (4)在現(xiàn)有的相關(guān)屈曲模式定義下,推導(dǎo)了畸變變形與整體變形之間的變形相關(guān)關(guān)系。從變形協(xié)調(diào)角度出發(fā),分析了相關(guān)屈曲產(chǎn)生的原因與機理,指出局部與畸變屈曲對截面參數(shù)的改變,是引起與整體屈曲相關(guān)作用的根本原因。同時形心與剪心偏移也是薄壁構(gòu)件特有的現(xiàn)象。此外,定義了新的屈曲模式,重點區(qū)分了整體屈曲與畸變-整體相關(guān)屈曲,新的模式能更準(zhǔn)確的反映構(gòu)件屈曲行為。 (5)基于模型分析了構(gòu)件在水平荷載作用下的破壞機理,過早地出現(xiàn)局部屈曲并產(chǎn)生集中性的理想塑性是冷彎薄壁型鋼C型構(gòu)件在壓彎循環(huán)荷載作用下破壞的根本原因。此外,進行了恢復(fù)力模型推導(dǎo)與擬合,提出了反映屈曲影響的雙剛度準(zhǔn)則,得到了影響滯回性能的重要參數(shù)。 (6)基于格構(gòu)機理模型,推導(dǎo)畸變臨界力的解析解,選擇直接對轉(zhuǎn)動剛度進行數(shù)值擬合的方法,得到彈性畸變臨界力的簡化計算表達式。定義了畸變域范圍,可根據(jù)構(gòu)件截面參數(shù),直接判斷構(gòu)件破壞模式,簡化設(shè)計過程�；跈C理分析,通過對整體屈曲慣性矩進行折減來考慮畸變屈曲的相關(guān)影響,推導(dǎo)擬合了簡化設(shè)計公式,并與原DSM設(shè)計法和試驗資料作對比,具備良好的精度。
[Abstract]:With the development of city and new countryside construction, especially the authoritative departments of the state have clearly pointed out that the new round of GDP growth mainly comes from the urbanization of rural areas. As a branch of industrialized light-weight steel structure, steel structure system attracts much attention. Its most remarkable advantage is that the construction cycle is short, which can improve the investment benefit and speed up the capital turnover; and the occupancy rate of construction site, construction waste, construction noise and so on are greatly reduced. At present, cold-formed thin-walled steel has been widely used in Low-Rise civil buildings. Its advantages are light weight, and with the progress of manufacturing technology, yield strength is getting higher and higher, and durability is getting better and better. At the same time, cold-formed thin-walled steel construction. Convenience is also incomparable with other traditional steel structures. These characteristics make cold-formed thin-walled steel has great advantages and development prospects in the background of industrialization of steel structure housing and construction of new countryside.
In this paper, the cold-formed thin-walled steel C-shaped members with the most extensive application and the highest degree of industrialization are selected as the research object. It is considered that there are still some worthy research points in the existing research on buckling mechanism, hysteretic behavior and design methods suitable for various sections.
(1) Based on Shanley's model, the whole process of one-dimensional bar buckling is deduced, and the buckling mechanism and influencing factors, including initial imperfections and section parameters, are analyzed in depth. On this basis, plasticity is divided into ideal plasticity and distributed plasticity according to the distribution of plastic region. At the same time, based on the buckling model, the relationship between R (plastic stiffness or post-buckling stiffness) and the buckling and plastic behavior of the members is analyzed, which is prepared for the buckling mechanism analysis of thin-walled members.
(2) Experiments and numerical simulations of cold-formed thin-walled C-shaped members are carried out, including hysteretic behavior under horizontal cyclic loading, buckling behavior and failure characteristics under static axial force, and composite action under static and cyclic loading. Complex force model and failure mechanism, failure mechanism and eccentricity effect of components under static axial force, as well as the mechanism of combination action, provide support for the verification of lattice mechanism model.
(3) The buckling behavior and failure mechanism of members subjected to horizontal cyclic load and static axial force are analyzed, and the lattice mechanism model of cold-formed thin-walled C-shaped members is proposed. The rationality of the lattice mechanism model is verified by numerical and experimental results. The influence mechanism of plate group effect is studied, and the formula for calculating half-wavelength of distortional buckling of members is obtained, which is compared with the classical method and numerical simulation.
(4) Based on the existing definition of buckling modes, the relationship between deformation and deformation is deduced. From the point of view of deformation compatibility, the causes and mechanism of buckling are analyzed. It is pointed out that the change of cross-section parameters caused by local buckling and distortion buckling is the fundamental cause of buckling. In addition, a new buckling mode is defined to distinguish the global buckling from the distortion-global buckling, which can more accurately reflect the buckling behavior of thin-walled members.
(5) The failure mechanism of cold-formed thin-walled C-section steel members subjected to horizontal loads is analyzed based on the model. The premature local buckling and the concentrative ideal plasticity are the fundamental reasons for the failure of cold-formed thin-walled C-section steel members subjected to cyclic compression and bending loads. The important parameters affecting the hysteretic behavior are obtained.
(6) Based on the lattice mechanism model, the analytical solution of the distortional critical force is deduced, and the simplified calculation formula of the elastic distortional critical force is obtained by directly fitting the rotational stiffness. Considering the influence of distortion buckling, the simplified design formula is deduced and fitted by reducing the integral buckling moment of inertia. The simplified design formula is compared with the original DSM design method and the experimental data, and has good accuracy.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：TU392.1

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本文編號：2206249