| dc.description.abstract | The developments of vibration-based tension force identification have increased in recent years and are widely adopted in determining the cable force in real cases. Research and development of existing methods are still being carried out to improve the results′ accuracy. Among the developed methods, two approaches become the basis of the current research. First, the effective vibration length concept has successfully revealed the cable force regardless of end restraints. Secondly, a two-mode frequency approach that developed to omit the bending stiffness information but still considers its effect. In other words, the second method implicitly replaces the cable bending stiffness that is difficult to be found by using two arbitrary mode frequencies.
The current work, which takes advantage of these two developed techniques, extends the two-mode frequency approach by adding an equivalent-effective length for any two modal pairings. This extended formula allows the two-mode frequency approach to be applied in any rotational stiffness support conditions. Some studies were conducted in this work to validate the proposed formula. Validation was done in theoretical, numerical, and experimental ways. Cable with hinged at both ends, fixed at both ends, and hinged-fixed supports were studied in theoretical and numerical validation. The experimental study investigated three types of support spring stiffness between the hinge and fixed end. This study also demonstrates the introduced formula in real cable testing involving stochastic subspace identification (SSI) as the operational modal analysis for dynamic system identification. Because this method requires multiple vibration measurements, the influence of sensor arrangement on force identification was also examined.
Overall, minor errors in all validation studies and demonstration of the method in a real cable system indicate that the two-mode combination method developed in this research is accurate and practical for field measurements. Moreover, this dissertation also contains some other detailed analyses and comparisons with other researchers′ work to enhance the discussion.
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