Experimental and numerical study on vibration mitigation of slender structures with TLCD under second-order effects

This study experimentally and numerically investigates the importance and methodology of designing a Tuned Liquid Column Damper (TLCD) system for a slender single-degree-of-freedom (SDOF) structure under second-order (P−Δ) effects. The dynamic characteristics of slender structures under P−Δ effects were experimentally tested and numerically validated with respect to the drift sensitivity coefficient (θ). Then, the optimum liquid column length of TLCD was calculated using experimental and numerical techniques. The study evaluated the performance of TLCDs designed with and without consideration of P−Δ effects based on structural responses in the frequency and time domains under free vibration, swept sine excitation, and seismic loads. Numerical models of the TLCD, the uncontrolled and the controlled structures were developed using individually obtained constitutive parameters and validated with State Space models for nonlinear and equivalent linear systems. Experimental results indicated that the TLCD system tuned with consideration of P−Δ effects exhibit significantly improved performance compared to the system designed without such consideration, showing average vibration mitigation ratios (VMR_PEAK) of 43.5 % for swept-sine excitation and 30.5 % for seismic loads in terms of maximum acceleration and displacement. The vibration mitigation ratios for RMS (VMR_RMS) acceleration and displacement values were, on average, 32.5 % across seismic loads. In addition, parametric analyses highlighted that TLCD systems neglecting P−Δ effects deviated from optimal configurations as θ increases, resulting in a notable decline in vibration mitigation performance. In conclusion, P−Δ effects substantially influence the dynamic properties of structures, making their consideration essential for the effective design of TLCD systems.