【摘要】：本文以《鋼結(jié)構(gòu)設(shè)計規(guī)范》國家標(biāo)準(zhǔn)改進(jìn)與完善的課題為背景，在總結(jié)國內(nèi)外已有的研究成果的基礎(chǔ)上，對高強度鋼材焊縫連接受力性能進(jìn)行了深入的試驗研究、數(shù)值模擬和理論分析。經(jīng)過研究表明，由于高強度鋼材本身的屈強比較高及延性弱于普通鋼的特性，高強度鋼材焊縫連接受力性能與普通強度鋼材相比存在較大差異，僅通過線性外推的設(shè)計方法不能滿足當(dāng)前工程的要求，需要針對高強度鋼材焊縫連接制定相應(yīng)的設(shè)計方法。 本文根據(jù)4個Q460C高強度鋼材與ER55級別焊絲焊縫連接的對接接頭試件，對Q460C等強匹配的對接焊縫焊接接頭的硬度進(jìn)行了測量，對焊接接頭的軸心拉伸性能進(jìn)行了試驗研究，得到了接頭位置的本構(gòu)關(guān)系。同時與采用同樣尺寸的Q345B等強匹配的焊接接頭軸心拉伸試驗研究進(jìn)行了對比。 針對鋼結(jié)構(gòu)焊縫連接中運用廣泛的正面角焊縫和側(cè)面角焊縫，本文設(shè)計了2組共10個試件分別測出了正面角焊縫搭接接頭的極限承載力、極限強度、破壞形態(tài)，以及側(cè)面角焊縫搭接接頭的極限抗剪承載力、極限剪切強度、破壞形態(tài)和焊縫變形性能，采用粘貼直角應(yīng)變花的方法測量了彈性階段側(cè)面角焊縫在純剪切軸向拉伸作用下，，其中心位置的表面應(yīng)力狀態(tài)分布。此后又運用有限元數(shù)值模擬軟件建立了側(cè)面角焊縫焊縫連接搭接接頭的非線性有限元模型，利用本文試驗及國外學(xué)者已有的，采用CO_2氣體保護(hù)焊焊接方法的共26個試驗結(jié)果對有限元模型進(jìn)行了驗證。 在有限元模型得到驗證的基礎(chǔ)上，采用有限元模型對與側(cè)面角焊縫搭接接頭相關(guān)的參數(shù)進(jìn)行參數(shù)分析，通過建立96組不同尺寸的模型，研究了母材屈服強度f_(b,y)、極限強度f_(b,u)、焊縫極限強度f_(w,u)、芯板長度L、芯板及蓋板厚度t、焊腳尺寸h_f、拉剪比A_n/A_s及焊縫長度L_w等參數(shù)對焊縫承載性能的影響。 針對側(cè)面角焊縫長焊縫在拉伸作用下應(yīng)力分布不均勻問題，本文對焊縫剪切面的剪應(yīng)力的應(yīng)力分布進(jìn)行了有限元模擬計算，定量的分析了側(cè)面角焊縫長焊縫的應(yīng)力分布規(guī)律和焊縫的不均勻性質(zhì)，并根據(jù)目前已有的規(guī)范，提出了對長焊縫承載能力的折減方法。
[Abstract]:Based on the project of improving and perfecting the national standard of steel structure design code, and on the basis of summarizing the existing research results at home and abroad, the mechanical properties of weld joint of high strength steel are studied deeply in this paper. Numerical simulation and theoretical analysis. The results show that the mechanical properties of weld joint of high strength steel are different from those of common strength steel due to its higher flexural strength and weaker ductility than that of ordinary steel. The design method based on linear extrapolation can not meet the requirements of current engineering, so it is necessary to establish a corresponding design method for the weld joint of high strength steel. In this paper, the hardness of Q460C high strength steel welded joint with ER55 grade welding wire is measured, and the axial tensile property of welded joint is studied. The constitutive relation of joint position is obtained. At the same time, the axial tensile test of welded joints using Q345B with the same size is compared. In view of the extensive use of frontal and lateral fillet welds in the weld connection of steel structures, two groups of 10 specimens were designed to measure the ultimate bearing capacity, ultimate strength and failure pattern of the lap joints of the frontal fillet welds, respectively. And the ultimate shear capacity, ultimate shear strength, failure form and weld deformation property of the side fillet lap joint were measured under pure shearing axial tension by using the method of sticking right angle strain splines. The distribution of the surface stress state at the center of it. Then the nonlinear finite element model of the side fillet weld joint is established by using the finite element numerical simulation software. The finite element model is verified by 26 test results of CO_2 gas shielded welding method. On the basis of the verification of the finite element model, the parameters related to the side fillet weld lap joint are analyzed by using the finite element model, and 96 groups of models with different sizes are established. The effects of such parameters as the yield strength of the base metal, the ultimate strength of the weld metal, the length of the core panel, the thickness of the core plate and the cover plate, the size of the welding foot, the A_n/A_s of the tensile shear ratio and the length of the weld seam LW on the bearing capacity of the weld are studied. Aiming at the problem of uneven stress distribution in long side fillet welds under tensile action, the stress distribution of shear stress in the weld shear plane is simulated by finite element method in this paper. In this paper, the stress distribution law of long side fillet weld and the non-uniform property of weld are analyzed quantitatively. According to the existing codes, the method of reducing the bearing capacity of long weld is put forward.
【學(xué)位授予單位】：清華大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU391

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