张弦梁结构振动方法索力识别(Ⅰ)：振动特性的参数分析

Vibration-based cable tension identification of a beam string structure(Ⅰ):parameter analysis of dynamic behavior

以构造形式简单且应用广泛的张弦梁结构为研究对象,对大跨度索屋盖结构中索的索力识别方法进行了初步研究。首先通过分析张弦梁结构的受力特点,提出了张弦梁结构下弦边索段的振动分析模型,分析此模型得到边索段的自由振动方程隐式解答,该解答反映了索力与频率、抗弯刚度及边界条件等之间的相关关系。然后通过引入一组能够反映抗弯刚度及支承条件对结构振动特性影响的无量纲参数,并利用非线性数值计算,分析了抗弯刚度及支承条件对拉索结构自振特性的影响规律,得出若干有益结论。在以上工作基础上,提出了索力识别的初步模型,可为该种结构仅利用频率测试索力提供参考。

Based on mechanical properties of a beam string structures(BSS),the vibration model of the side cable at lower chord of the BSS was proposed first.The implicit free vibration solution of the cable was obtained by analyzing the vibration model herein.The solution reflected the recurrent relationship among cable tension,natural frequencies,flexural rigidity and boundary conditions.Based on the solution,nonlinear numerical computation was conducted to study how flexural rigidity and boundary conditions influenced the free vibration properties of the cable by introducing a set of dimensionless parameters,which represented flexural rigidity and boundary conditions,respectively.Some instructive conclusions were obtained herein.Furthermore,the preliminary identification model was proposed according to the above analysis.The work done above provided helpful references for cable tension evaluation of a BSS based on frequency measurement.