Optimal Tuning of Amplitude Proportional Coulomb Friction Damper for Maximum Cable Damping
Optimal Tuning of Amplitude Proportional Coulomb Friction Damper for Maximum Cable Damping
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DOI：
10.1061/(asce)0733-9445(2010)136:2(123
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发表时间：
2010-02
期刊：
影响因子：
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通讯作者：
F. Weber;J. Høgsberg;S. Krenk
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文献类型：
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作者：
F. Weber;J. Høgsberg;S. Krenk
本文以拉索第一阶振型附加阻尼最大为优化准则，数值研究了拉索库仑摩擦阻尼器的最优调谐问题。库仑摩擦阻尼器的最佳摩擦力水平的表达式遵循线性粘滞阻尼器通过谐波平均。结果表明，摩擦力水平必须与阻尼器位置处的索幅成比例地调节，这是通过幅值反馈来实现的，是真实的实时的。这种自适应阻尼器的性能进行评估模拟自由衰减曲线的阻尼估计。结果表明，在理论最优值下，阻尼效率与期望值吻合较好。然而，最大阻尼较大，并且在力与振幅比为分析值的1.4倍时实现。研究表明，阻尼的增加是由于振幅比例库仑摩擦阻尼器在其上下位置夹持缆索引起的能量溢出到更高的模式。由此产生的非正弦索运动显然违反了纯谐波运动的假设，并解释了为什么这种阻尼器必须从最佳线性粘滞阻尼器不同的调谐。
This paper investigates numerically the optimal tuning of Coulomb friction dampers on cables, where the optimality criterion is maximum additional damping in the first vibration mode. The expression for the optimal friction force level of Coulomb friction dampers follows from the linear viscous damper via harmonic averaging. It turns out that the friction force level has to be adjusted in proportion to cable amplitude at damper position which is realized by amplitude feedback in real time. The performance of this adaptive damper is assessed by simulated free decay curves from which the damping is estimated. It is found that the damping efficiency agrees well with the expected value at the theoretical optimum. However, maximum damping is larger and achieved at a force to amplitude ratio of 1.4 times the analytical value. Investigations show that the increased damping results from energy spillover to higher modes evoked by the amplitude proportional Coulomb friction damper which clamps the cable at its upper and lower positions. The resulting nonsinusoidal cable motion clearly violates the assumption of pure harmonic motion and explains why such dampers have to be tuned differently from optimal linear viscous dampers.