屈曲约束支撑线接触长度的简化计算  

Simplified calculation on length of line-contact of buckling-restrained brace

作　　者：尤国萍[1] 吴京[1] 

机构地区：[1]东南大学土木工程学院,南京210096

出　　处：《东南大学学报（自然科学版）》2009年第S2期222-226,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(50878055);江苏省自然科学基金资助项目(BK2008313)

摘　　要：针对屈曲约束支撑,提出了核心单元与约束单元由点接触过渡到线接触时,线接触长度的简化计算方法.针对所采用的力学模型,利用轴心受压杆件的四阶微分方程,忽略不稳定的偶数阶反对称屈曲模态,并引入线接触终止点处杆件曲率为零的简化假定,推导了核心单元与约束单元发生线接触时的荷载变化范围以及挠度计算公式,重点讨论线接触段最大长度的简化计算.理论分析表明:线接触长度与核心单元和约束单元的间隙无关,仅与核心单元两端的约束情况有关;当核心单元两端采用铰接时,线接触段的最大长度为L/2(L为核心单元的长度),随着轴向荷载P的增大,将发生线接触段的再次屈曲;当两端采用固定连接时,线接触段的最大长度为L/3,随着轴向荷载P的增大,也将发生再次屈曲.该公式不仅物理意义明确,而且具有简单的表达形式,适合进行接触长度的快速求解.A simplified calculation method on the length of line-contact,when the core cell and the restraining cell are transited from point contact to line contact in a buckling-restrained brace,is proposed.Aiming at the mechanical model which is adopted,according to the forth differential equations of axially compressive members,the unstable even-order antisymmetric buckling mode is neglected,and the rod curvature at the end point of line contact is supposed to be 0 for simplification.The formula for load range and deflection calculation during the line contact stage are derived,especially the calculation formula for the maximum length of line contact.Theoretical analysis results indicate that the length of line contact is independent of the gap between the core cell and the restraining cell,and only depends on the constrained boundary conditions at both ends.If hinged ends are adopted,the maximum length of line contact is L/2(L denotes the length of the core cell);as the end load P increases,the secondary buckling of the line contact portion occurs.If fixed ends are adopted,the maximum length is L/3;as the end load P increases,the secondary buckling occurs again.The formula derived from this paper has not only a clear physical meaning,but also a simple expression.It is suitable for the fast solution of the line-contact length.

关 键 词：屈曲约束支撑 轴压 线接触 线接触长度 

分 类 号：TU311.4[建筑科学—结构工程]