Recent studies demonstrated that TMD control performances and robustness can be enhanced by increasing its mass, realizing a non-conventional TMD. In case of frame structures, a way to apply this concept is to use masses already present in the structure to be converted into tuned masses, realizing segmented upper stories or sliding roof systems, isolated from the substructure and acting as TMD. Non-conventional TMD is suitable for new constructions as well as for retrofitted ones since its impact on the structure is minimal, not requiring additional weight. The present memory illustrates preliminary experimental results of shaking table tests conducted on a frame structure equipped with non-conventional TMD. The control system is realized by isolating the structure top story mass and connecting it to the substructure with two high damping rubber bearings placed in series. The effects introduced by the nonlinear non-conventional TMD on the modification of the dynamic behavior of the frame story structure are outlined. In addition, the nonlinearities induced by the use of the adopted isolators are investigated. Different configurations are tested: (1) the reference 4-story structure, (2) the 3-story structure with the support plane, (3) the 3-story structure equipped with the non-conventional TMD. The simple input motion condition considered is a white noise repeated at different intensities. The dynamic response in the various configurations, evaluated in terms of pseudo-frequency response functions and force displacement cycles, shows that the introduction of the TMD is always effective to control the first mode of the primary structure and all modes of the non-segmented original structure at the TMD level. By varying the input intensity, the structure shows decreasing frequencies evidencing the softening behavior introduced by the isolators whereas damping exchanges between the first two modes, moving from the second to the first one, but maintaining constant the mean value in the range of intensities investigated.
Preliminary experimental results of shaking table tests on mdof structure equipped with non-conventional tmd
Basili M;
2020-01-01
Abstract
Recent studies demonstrated that TMD control performances and robustness can be enhanced by increasing its mass, realizing a non-conventional TMD. In case of frame structures, a way to apply this concept is to use masses already present in the structure to be converted into tuned masses, realizing segmented upper stories or sliding roof systems, isolated from the substructure and acting as TMD. Non-conventional TMD is suitable for new constructions as well as for retrofitted ones since its impact on the structure is minimal, not requiring additional weight. The present memory illustrates preliminary experimental results of shaking table tests conducted on a frame structure equipped with non-conventional TMD. The control system is realized by isolating the structure top story mass and connecting it to the substructure with two high damping rubber bearings placed in series. The effects introduced by the nonlinear non-conventional TMD on the modification of the dynamic behavior of the frame story structure are outlined. In addition, the nonlinearities induced by the use of the adopted isolators are investigated. Different configurations are tested: (1) the reference 4-story structure, (2) the 3-story structure with the support plane, (3) the 3-story structure equipped with the non-conventional TMD. The simple input motion condition considered is a white noise repeated at different intensities. The dynamic response in the various configurations, evaluated in terms of pseudo-frequency response functions and force displacement cycles, shows that the introduction of the TMD is always effective to control the first mode of the primary structure and all modes of the non-segmented original structure at the TMD level. By varying the input intensity, the structure shows decreasing frequencies evidencing the softening behavior introduced by the isolators whereas damping exchanges between the first two modes, moving from the second to the first one, but maintaining constant the mean value in the range of intensities investigated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
