H形截面钢构件受弯性能及板件相关作用机制

Bending performance and mechanism of plate interaction in H-shaped section steel members

关键词:  板件相关作用  H形截面  纯弯试验  受弯承载力  截面塑性发展能力

Key words:  plate interaction  H-section  pure bending test  flexural load capacity  cross-sectional plasticity development capability

摘要:

为探究H形截面受弯构件承载性能及板件相关作用,对4根不同翼缘和腹板宽厚比的焊接H形截面钢梁进行四点纯弯加载试验,分析试件的破坏模态、力-位移曲线、极限受弯承载力及延性等性能指标,并通过对比相同尺寸的腹板在不同宽厚比翼缘支撑条件下的应变及腹板单板承载力的发展情况,揭示该情况下板件相关作用的机制。在试验基础上,采用ABAQUS建立经试验校准的有限元模型,采用该建模方法进行参数分析；对参数分析构件进行翼缘及腹板受弯承载力的拆分,进一步探究受弯情况下板件相关作用的规律。试验及参数分析结果均表明:板件局部屈曲的发生基本对应着H形截面构件极限受弯承载能力,而板件宽厚比是影响局部屈曲的重要因素,板件相关作用表现为不同宽厚比的板件通过改变对其相邻板件的约束作用影响相邻板件的屈曲时刻,影响单块板件承载能力,从而影响构件整体承载性能。最后,基于参数分析结果对构件极限承载能力进行归一化处理,提出了H形截面受弯状态下考虑板件相关作用的S2~S4级截面分类方法,对比结果表明,本文提出的截面分类限值与试验结果吻合良好,且能合理体现板件相关作用对于截面真实承载能力的影响。

Abstract:

To explore the load-bearing performance and the role of plate components in H-shaped section bending members, four-point pure bending tests were conducted on four welded H-shaped steel beams with different flange and web width-to-thickness ratios. The failure mode, force-displacement curve, ultimate bending capacity, and ductility of the test pieces were analyzed. By comparing the strain development and single plate bearing capacity of the web plates under different flange support conditions with the same dimensions, the mechanism of plate component interaction in this situation was revealed. Based on the experimental results, a calibrated finite element model was established using ABAQUS, and parameter analysis was conducted using this modeling method. By separating the flange and web plate bending load capacities of the parameterized components, the law of plate component interaction under bending conditions was further explored. The experimental and parametric analysis results both indicate that the occurrence of local buckling in the plate elements generally corresponds to the ultimate bending capacity of the H-shaped section members. The width-to-thickness ratio of the plates is a significant factor affecting local buckling. Furthermore, the interaction between the plates manifests as plates with different width-to-thickness ratios influencing the buckling timing of adjacent plates by altering the constraints on them, which affects the load-bearing capacity of individual plates and thus impacts the overall load-bearing performance of the member. Finally, based on the parameter analysis results, the ultimate load-bearing capacity of the members was normalized, and an S2-S4 grade section classification method considering the interaction of plate elements under bending conditions for H-shaped sections was proposed. The comparison results show that the section classification limits proposed in this paper match well with the experimental results and can reasonably reflect the impact of plate element interactions on the actual load-bearing capacity of the section.