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对由厚度为6.0mm、名义屈服强度为315.0MPa的钢板制成的H型钢进行了一系列弯曲试验,研究焊接H型钢的抗弯强度。截面几何形状和侧向边界条件决定了薄壁受弯构件的屈曲形式(局部屈曲、侧向扭转屈曲或交互屈曲)。翼缘或腹板宽厚比较大的受弯构件最先出现局部屈曲,继而发生侧向扭转屈曲,在交互屈曲作用下材料最终破坏。侧向扭转屈曲下局部屈曲对抗弯强度有负面影响。计算薄壁抗弯构件名义屈服应力时应将该现象考虑在内。对翼缘和腹板宽厚比不同的焊接H型钢梁进行了试验。进行有限元分析时将局部和侧向扭转屈曲模态的初始缺陷及残余应力考虑在内。基于考虑焊接型材局部和侧向扭转屈曲相互作用的试验和有限元分析结果,给出直接强度法(DSM)计算抗弯强度的简化公式。计算强度曲线与AISC规范(2005),EC3(2003)及试验结果进行比较,验证了DSM方法所计算的强度曲线的准确性。通过试验得出薄壁焊接H型钢的抗弯强度和结构性能的有关结论。
A series of bending tests on H-section steel made of steel plate with a thickness of 6.0mm and a nominal yield strength of 315.0MPa were carried out to study the flexural strength of welded H-section steel. Section geometry and lateral boundary conditions determine the buckling pattern of a thin-walled flexural member (local buckling, lateral torsional buckling, or reciprocal buckling). Bending or flexural members with larger flanges or webs are the first to have partial buckling, followed by lateral torsional buckling, which eventually damages the material under reciprocal buckling. Local buckling under lateral torsional buckling has a negative effect on the bending strength. This phenomenon should be taken into account when calculating the nominal yield stress of thin-walled flexural members. Experiments were conducted on welded H-beams with different flange-to-web width-thickness ratios. Finite element analysis takes into account the initial defects and residual stresses in local and lateral torsional buckling modalities. Based on the experimental and finite element analysis considering the local and lateral buckling buckling of welded profiles, a simplified formula for calculating the flexural strength by direct strength method (DSM) is given. The calculated strength curves are compared with the AISC specifications (2005), EC3 (2003) and the test results to verify the accuracy of the intensity curves calculated by the DSM method. The conclusion about the flexural strength and structural properties of H-section thin-walled welded steel is obtained through experiments.