不同失效模式下平面张弦梁结构受力全过程刚度变化

摘要

To solve the problem that the current research lacks systematizations on the law of stiffness changes of plane beam string structure in full loading process,intensive study was performed with the strategies of analytical deduction,finite element analysis and experimental validation.Firstly,based on the first order analysis method,the calculating formulas of mid-span vertical displacement and member internal force were obtained for a simplified plane beam string structure model.Then,the effects were studied on the global stiffness with different bending stiffness of upper chord and axial stiffness ratio of upper chord to lower chord.Finally,the reducing degree of global stiffness was analyzed in full loading process for different plane beam string structures.The results indicate that the bending stiffness of upper chord influences the global stiffness little when each parameter adopts common values.The failure modes hold the brittle characteristics for plane beam string structure.%针对现有关于平面张弦梁结构受力全过程中刚度变化规律研究不够系统化的不足,采用理论推导、有限元分析和试验验证等策略对此问题进行深入分析.首先,运用一阶方法推导简化平面张弦梁结构模型在外荷载作用下的跨中竖向位移和杆件内力的计算公式.在此基础上,研究上弦抗弯刚度及上下弦轴向刚度比这2个参数对结构竖向整体刚度的影响规律.最后,分析多个平面张弦梁结构模型在受力全过程中的刚度下降程度.结果表明:当各参数在常用范围内取值时,上弦抗弯刚度对结构整体刚度的影响不大.该结构的多种承载破坏模式均具有脆性破坏的特征.