Upon having the construction of a new church near completion, walking induced vibration was perceived on a long span balcony. DEICON conducted on-site measurements and identified the first two natural frequencies of the balcony. In addition, the participating mass and the damping ratio of mode 1 of the balcony were evaluated. DEICON designed and fabricated […]
Read MoreUpon having the construction of a new church near completion, walking induced vibration was perceived on a long span balcony. DEICON conducted on-site measurements and identified the first two natural frequencies of the balcony. In addition, the participating mass and the damping ratio of mode 1 of the balcony was evaluated. Tuned damping was used […]
Read MoreDEICON designed and fabricated the components for vibration isolation of a massive 110,000 lb, industrial process equipment, subject to random perturbation. The isolators used in the random vibration isolation system are made up of low-stiffness coil springs paired with viscous dampers. Motion control schemes were incorporated into the isolation system to manage the lateral excursion […]
Read MoreWalking induced vibration of composite floor system of an office building was controlled at 4 bays, using 8 x 1500 lb tuned mass dampers (TMDs). The measured natural frequencies of the floor system were used in tuning the TMDs targeting the first vibration mode of two bays and first two vibration modes of the other […]
Read MoreFluid/structure interaction and the operation of one of the natural gas compressors imparted dynamic forces onto one of the compressed natural gas piping systems of a power plant. The frequency of this dynamic perturbation happened to nearly match the first resonant frequency of the piping system, which in turn resulted in excessive resonant vibration of […]
Read MorePendulum tuned mass dampers (PTMDs) are commonly used in adding damping to tall structures, including high-rise buildings, control and communication towers, stacks, etc. These multi-directional TMDs, which are made up of mass blocks suspended by steel cables or rods, can readily be tuned to the very low natural frequencies associated with the primary modes of […]
Read MoreThe extent of vibration energy that a passive TMD dissipates as well as its effective frequency range (bandwidth) increase with an increase in the mass ratio of the TMD. In addition, the amount of internal damping built into the make-up of a passive TMD increases with the size of that TMD. The TMDs used in […]
Read MoreThe use of a tuned damper or a dynamic absorber in time-varying systems can only be effective if they are adjustable (semi-active) and continuously returned to the current resonant frequency of the system. Such dampers require a tuning algorithm that can automatically adjust the adjustable parameter of the tuned damper/absorber, e.g., the stiffness of the […]
Read MoreDEICON’s patented, semi-actively controlled, ‘air suspended tuned mass damper’ (TMD) uses one/multiple air spring(s) as both the restoring (resilient) and the energy dissipating (damping) elements. Feedback control is used to adjust the stiffness and damping of the air spring(s). The schematic of a tuned mass damper installed on a structure is shown in Figure 1. […]
Read MoreTo lower the vibration level of a monumental staircase, one 500 lb tuned mass damper (TMD) was designed, fabricated, and appended to the structure. The natural frequency of the staircase was measured and used for tuning the TMD. Figure 1 shows the landing of the staircase with two of the measurement locations highlighted. Monumental aesthetically […]
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