低屈服点钢闭口矩形截面连梁力学性能研究

RESEARCH ON MECHANICAL PROPERTIES OF TUBULAR CROSS SECTION LINKS MADE OF LOW-YIELD-POINT STEEL

  • 摘要: 闭口矩形截面连梁有着变形能力强、面外稳定性强的优点,在建筑抗震设计领域有着独特的优势与推广价值。采用低屈服点钢时,闭口矩形截面连梁的减震耗能能力可以得到进一步提升。该文通过试验研究、数值模拟与理论分析的方法,重点研究了该构件在往复加载工况下力学性能,并给出了工程应用中的设计建议。以连梁长度等五个参数为试验变量设计了12个足尺试件,通过往复剪切加载,测量得到连梁承载力、变形能力、塑性超强能力等力学性能,并根据连梁失效模式推导出了连梁工作受力机制。对比各试件力学性能,总结了连梁几何参数对力学性能的影响规律。其次建立了闭口矩形截面连梁精细化数值模型,可以准确地模拟连梁在往复剪切加载制度下的屈服、失效、塑性强化等力学行为,计算连梁耗能能力等关键性能。最后,设计数值模型并进行数值试验,定量地得出了连梁有效长度系数等设计参数与屈服承载力、塑性超强系数的定量关系,发现了在腹板失效前后,翼缘在连梁工作中由面外约束到参与变形耗能的作用转变。

     

    Abstract: Tubular cross section links (TCSLs) exhibit high deformation capacity and strong out-of-plane stability, offering unique advantages and significant applicability in seismic design. With low-yield-point (LYP) steel, these TCSLs demonstrate enhanced energy dissipation, further augmenting their seismic performance. This study, through experiments, simulations and theoretical analysis, investigates the cyclic loading performance of TCSLs and offers engineering design recommendations. Twelve full-scale specimens were designed and tested with five parameters, including link length, to assess load capacity, deformation capacity and overstrength. The failure modes were analyzed to reveal the internal force mechanisms. The comparisons of mechanical properties established the effects of geometric parameters. Subsequently, the finite element models of TCSLs was developed to accurately simulate the yielding, failure and overstrength behaviors under cyclic shear loading, effectively quantifying energy dissipation. Finally, the relationships between design parameters such as link length ratio and factors like yield capacity and overstrength factor were determined with numerical simulation. A key finding is the transition of the flanges' role from providing out-of-plane restraint to active energy dissipation as the web experiences failure.

     

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