柔索索力主频阶次误差及支承条件误差

为研究柔索索力测试中拉索自振频率阶次和支承条件对索力测试误差的影响规律,利用动平衡法推导了考虑弯曲刚度的柔索自振方程和自振频率公式,采用瑞利能量法分析了弹性支承条件和附加质量对拉索自振频率的影响.研究发现频率阶次对索力计算公式的影响符合二次抛物线分布特征,附加质量使拉索的自振频率减小,传感器等测试用的质量块的影响可以忽略不计,弹性支承引起的误差与弹性链杆刚度成线性关系,而且与主频的阶次有关.分析和试验结论对大跨度柔索承重结构如斜拉桥和悬索桥的索力测试具有指导意义.

Frequency number error and support condition of flexible cable tension

In order to study the test errors of cable tension due to natural frequency order and support condition, based on dynamical equilibrium of infinitesimal element, the formulas of natural frequency and cable tension were deduced under flexural rigidity. In terms of Ray-Leiy energy method, the influence of additional mass and elastic constrain on natural frequency was studied. The influence rule of test error due to test frequency order has the character of two times parabola. The natural frequency can decrease when added additional mass, and the influence of sensors mass may be neglected during test. The cable tension error due to elastic support has linear relation with the axial rigidity of support link, which is also related to natural frequency order. All this are instructive to cable tension measurement such as cable-stayed bridge, suspension bridge and other cable-stayed structures. 1 tab, 5 figs, 7 refs.