基于广义塑性铰线法的压弯钢构件极限承载力计算.docVIP

基于广义塑性铰线法的压弯钢构件极限承载力计算 　　摘要：采用广义塑性铰线法对H形截面钢构件绕强轴压弯区段板件组的极限状态进行了分析，并选用合理假定求解受压翼缘屈曲后达到的极限承载力；分析了表征极限状态截面的应力分布，并研究了周边板件约束与受压翼缘板件厚实程度对屈曲翼缘发展塑性的影响；采用考虑板件屈曲相关的等效荷载法分析了构件截面极限状态应力分布，针对广义塑性铰线法相对于传统塑性铰线法的适用性拓展及其应用现状，分析其存在的问题并做出解答；将计算结果与试验结果及有限元结果进行了对比。结果表明：基于广义塑性铰线法可准确预判构件绕强轴压弯的极限承载力。 　　关键词：广义塑性铰线法；H形截面；压弯钢构件；局部失稳；板件相关作用；极限承载力 　　中图分类号：TU391文献标志码：A 　　Abstract： The limit state of plate group bending about strong axis of Hsection steel beamcolumns was investigated based on generalized yield line method. Reasonable assumptions were chosen to solve the ultimate bearing capacity of the compression flange after buckling. The stress distribution of the cross section under the limit state and influences on plastic status of buckling flange derived from the constraint of circumjacent plates and compactness of the compression flange were discussed. A method denoted as “equivalent load method” was proposed describing the stress distribution of the cross section under the limit state considering interactive effect of buckling plates. On the basis of the review on extended applicability of generalized yield line method compared to classical yield line theory， the existing problems of generalized yield line method were analyzed and feasible solutions were proposed. The calculation results were compared with test results and finite element analysis results. Results show that the ultimate bearing capacity of beamcolumns bending about strong axis can be accurately predicted based on generalized yield line method. 　　Key words： [WT]generalized yield line method； Hsection； beamcolumn； local buckling； interactive effect of plate； ultimate bearing capacity 　　0引言 　　存在弯矩作用的钢构件其极限状态之一就是构件的部分区段形成具有一定转动能力的铰区。对于厚实截面构件，其铰区可以全面发展塑性，形成塑性铰；对于薄柔截面构件，其铰区受板件屈曲控制，形成屈曲铰[1]。线型单元计算简图将铰区简化为集中于一个截面的理想铰，以该种特征截面代表铰区区段。文献[2]，[3]研究了H形截面压弯钢构件承载力极限状态，以有效宽度法求解极限承载力。对于极限状态发生板件屈曲的构件，考察其破坏的变形模式，发现铰区范围的板件形成若干塑性集中于条状的机构；简单以特征截面代表区段不能反映塑性变形沿区段长度方向分布的特点，也难以了解构件中受到相互约束板件的应力状态。 　　依据板件承载力极限状态的内力分布特征，可用塑性铰线法（屈服线理论）的空间机构模型求