含非连续支撑的非对称交叉斜撑体系的计算长度系数（英文）

Effective length factor of a non-symmetrical cross-bracing system with a discontinuous diagonal

目的:非矩形平面框架致使其交叉斜撑体系具有非对称性,而采用了非连续支撑的非对称非连续交叉支撑体系的面外稳定问题更为复杂。本文旨在通过建立无量纲稳定特征方程,从理论上深入阐释该交叉支撑体系的面外屈曲特征,并为工程设计提供显式的压杆计算长度系数的计算公式。创新点:1.建立一般情况下非对称非连续交叉斜撑体系的无量纲特征方程;2.针对各种可能受力工况,详细分析该交叉支撑体系的面外屈曲特征,并给出理论解释;3.提出非对称非连续交叉斜撑体系中压杆计算长度系数的显式经验计算公式。方法:1.通过对非对称非连续交叉支撑体系进行弹性面外屈曲建模,以及稳定平衡方程的无量纲化,推导出其相应的特征方程;2.通过变量替换,揭示其内在对称性,从而为经验公式的构造提供依据;3.针对各种受力工况,进行求解域分析和确定,完成特征方程的求解,以进行面外屈曲特征分析,并提出压杆计算长度系数的经验公式;4.利用经验公式对多个实例进行计算,并与基于有限元的刚度法结果以及以往的文献数据进行比较,以验证经验公式的可靠性。结论:1.推导出了非对称非连续交叉斜撑体系的特征方程;采用无量纲参数后,该方程具有一般性。2.通过变量替换,该方程可以转换为与单轴几何对称交叉斜撑相同的特征方程形式。3.当交叉斜撑中的连续杆和非连续杆同时受压时,非连续杆将率先失稳。4.针对各种受力工况,提出了交叉支撑体系的压杆计算长度系数的显式经验公式,且计算结果兼具可靠性和准确性。

A non-rectangular frame panel usually contains an asymmetrical cross-bracing system with interrupted diagonals,leading to a more complicated buckling behavior than a symmetrical bracing system with continuous diagonals.There have been many studies of the stability theory of symmetrical cross-bracing systems,but few related to non-symmetrical systems.In this study,we analyzed elastic out-of-plane buckling of a general non-symmetrical cross-bracing system with a discontinuous diagonal.The discontinuous and continuous diagonals have different material and geometrical properties,and are not intersected at their mid-spans.A characteristic equation is presented to compute the critical loading of a non-symmetrical cross-bracing system when the supporting diagonal is under either compression or tension.The results show that the characteristic equation of a non-symmetrical bracing system can be transformed into a form the same as that of a geometrically mono-symmetrical system.To facilitate design applications,direct closed-form empirical equations of effective length factor are established for a general non-symmetrical cross-bracing case.The validity of the proposed empirical equations was verified by comparing predicted and theoretical results,and those from a stiffness approach.