Q460高强度钢材焊缝连接受力性能和计算模型研究

发布时间：2018-09-18 08:19

【摘要】：本文以《钢结构设计规范》国家标准改进与完善的课题为背景，在总结国内外已有的研究成果的基础上，对高强度钢材焊缝连接受力性能进行了深入的试验研究、数值模拟和理论分析。经过研究表明，由于高强度钢材本身的屈强比较高及延性弱于普通钢的特性，高强度钢材焊缝连接受力性能与普通强度钢材相比存在较大差异，仅通过线性外推的设计方法不能满足当前工程的要求，需要针对高强度钢材焊缝连接制定相应的设计方法。本文根据4个Q460C高强度钢材与ER55级别焊丝焊缝连接的对接接头试件，对Q460C等强匹配的对接焊缝焊接接头的硬度进行了测量，对焊接接头的轴心拉伸性能进行了试验研究，得到了接头位置的本构关系。同时与采用同样尺寸的Q345B等强匹配的焊接接头轴心拉伸试验研究进行了对比。针对钢结构焊缝连接中运用广泛的正面角焊缝和侧面角焊缝，本文设计了2组共10个试件分别测出了正面角焊缝搭接接头的极限承载力、极限强度、破坏形态，以及侧面角焊缝搭接接头的极限抗剪承载力、极限剪切强度、破坏形态和焊缝变形性能，采用粘贴直角应变花的方法测量了弹性阶段侧面角焊缝在纯剪切轴向拉伸作用下，，其中心位置的表面应力状态分布。此后又运用有限元数值模拟软件建立了侧面角焊缝焊缝连接搭接接头的非线性有限元模型，利用本文试验及国外学者已有的，采用CO_2气体保护焊焊接方法的共26个试验结果对有限元模型进行了验证。在有限元模型得到验证的基础上，采用有限元模型对与侧面角焊缝搭接接头相关的参数进行参数分析，通过建立96组不同尺寸的模型，研究了母材屈服强度f_(b,y)、极限强度f_(b,u)、焊缝极限强度f_(w,u)、芯板长度L、芯板及盖板厚度t、焊脚尺寸h_f、拉剪比A_n/A_s及焊缝长度L_w等参数对焊缝承载性能的影响。针对侧面角焊缝长焊缝在拉伸作用下应力分布不均匀问题，本文对焊缝剪切面的剪应力的应力分布进行了有限元模拟计算，定量的分析了侧面角焊缝长焊缝的应力分布规律和焊缝的不均匀性质，并根据目前已有的规范，提出了对长焊缝承载能力的折减方法。
[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.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU391

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