發(fā)布時間：2018-11-11 17:36

【摘要】：在實(shí)際工程中,當(dāng)荷載偏離鋼梁截面的剪力中心,鋼梁會因?yàn)槠氖芰Χ惺軓澟ぢ?lián)合作用。這樣的受力方式在一定程度上影響到構(gòu)件的承載能力以及變形特點(diǎn),而現(xiàn)有設(shè)計規(guī)范卻鮮有這方面的具體規(guī)定。另外,對于鋼梁受彎扭共同作用的研究,國內(nèi)外大多數(shù)工作都是關(guān)于工字型鋼梁和冷彎C型鋼梁,很少有涉及到并深入研究彎扭聯(lián)合作用下的槽型鋼梁的承載力特性。因此,本文對于槽型鋼梁在彎扭聯(lián)合作用下的受力性能進(jìn)行研究分析。首先從力學(xué)的基礎(chǔ)理論出發(fā)對槽型鋼梁進(jìn)行線彈性分析,其中包括:(1)對槽型鋼梁進(jìn)行受彎分析,并根據(jù)規(guī)范的應(yīng)力計算公式給出相應(yīng)的應(yīng)力圖;(2)根據(jù)開口薄壁桿件約束扭轉(zhuǎn)理論,對槽型鋼梁進(jìn)行扭轉(zhuǎn)分析,推導(dǎo)了槽型鋼梁約束扭轉(zhuǎn)應(yīng)力的計算公式并得到槽型截面的約束扭轉(zhuǎn)應(yīng)力圖;(3)在前兩項(xiàng)工作的基礎(chǔ)上對槽型鋼梁進(jìn)行彎扭聯(lián)合作用下的受力分析,從而根據(jù)彎扭聯(lián)合作用下槽型鋼梁的應(yīng)力組成,得到彎扭聯(lián)合作用下槽型鋼梁截面的正應(yīng)力分布規(guī)律。其次,利用大型有限元軟件ANSYS,同時考慮材料非線性和幾何非線性,對本文的研究對象建立有限元分析模型,并采用弧長法進(jìn)行求解計算。將有限元結(jié)果與我國的《鋼結(jié)構(gòu)設(shè)計規(guī)范》(GB 50017-2003)以及《冷彎薄壁型鋼結(jié)構(gòu)技術(shù)規(guī)范》(GB 50018-2002)中關(guān)于槽型鋼梁整體穩(wěn)定性計算的理論公式所得結(jié)果相比較,分析這兩本規(guī)范中關(guān)于槽型鋼梁整體穩(wěn)定性計算的區(qū)別。并將分析結(jié)論與相關(guān)文獻(xiàn)的結(jié)論對比,證明本文模型的正確性。最后,利用本文建立的有限元分析模型,對槽型鋼梁承受跨中偏心集中荷載和滿跨偏心均布荷載作用分別進(jìn)行非線性屈曲分析,求得槽型鋼梁在各荷載工況下的極限荷載,分析槽型鋼梁在橫向偏心荷載作用下的失穩(wěn)形式及其承載力變化規(guī)律。根據(jù)PutPi相關(guān)公式進(jìn)行猜測,在相關(guān)理論的基礎(chǔ)上引入一個簡化的名義極限扭矩來分析槽型鋼梁在橫向偏心荷載作用下極限彎矩和極限扭矩的相關(guān)關(guān)系,通過軟件MATLAB的回歸分析得到其相關(guān)關(guān)系的表達(dá)式,并將其與PutPi相關(guān)公式對比來驗(yàn)證本文工作的必要性和合理性。
[Abstract]:In practical engineering, when the load deviates from the shear center of the steel beam section, the steel beam will be subjected to the combined bending and torsion action because of the eccentric force. To a certain extent, the bearing capacity and deformation characteristics of members are affected by such a stress mode, but the existing design codes rarely have specific provisions in this respect. In addition, most of the researches on the bending and torsional interaction of steel beams are related to I-shaped steel beams and cold-formed C-type steel beams at home and abroad, and seldom involve and deeply study the bearing capacity characteristics of grooved steel beams under the combined action of bending and torsion. Therefore, this paper studies and analyzes the mechanical behavior of the groove steel beam under the action of bending and torsion. Based on the basic theory of mechanics, the linear elastic analysis of slotted steel beams is first carried out, which includes: (1) bending analysis of slotted steel beams, and the corresponding stress diagrams are given according to the stress calculation formula of the code; (2) according to the torsion theory of thin-walled open member, torsional analysis is carried out on the slotted steel beam, and the formula for calculating the constrained torsional stress of the slotted steel beam is derived, and the constrained torsional stress diagram of the slot section is obtained. (3) on the basis of the first two works, the stress of the slotted steel beam under the combined action of bending and torsion is analyzed, and according to the stress composition of the slotted steel beam under the combined action of bending and torsion, The normal stress distribution of the section of steel beam is obtained under the action of bending and torsion. Secondly, the finite element analysis model is established by using the large-scale finite element software ANSYS, to consider both material and geometric nonlinearity, and the arc length method is used to solve the problem. The results obtained by finite element method are compared with those obtained from the theoretical formulas for the calculation of the overall stability of steel girders in the Code for Design of Steel structures (GB 50017-2003) and the Technical Specification for Cold-Formed Thin-walled Steel structures (GB 50018-2002) in China. This paper analyzes the difference between the calculation of the overall stability of slotted steel beams in these two codes. The conclusion of this paper is proved to be correct by comparing the conclusion of the analysis with the conclusion of related literature. Finally, by using the finite element analysis model established in this paper, the nonlinear buckling analysis is carried out for the beam bearing eccentric concentrated load and full span eccentricity distribution load, respectively, and the ultimate load of the groove steel beam under various load conditions is obtained. The buckling mode and bearing capacity of steel beams with groove under transverse eccentric load are analyzed. Based on the PutPi formula, a simplified nominal limit torque is introduced to analyze the relationship between ultimate bending moment and ultimate torque under transverse eccentric load. Through the regression analysis of software MATLAB, the expression of the correlation relation is obtained and compared with the PutPi correlation formula to verify the necessity and rationality of the work in this paper.
【學(xué)位授予單位】：武漢理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU391

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本文編號：2325629