Search Results (4)

Originally proposed by the authors, the spring pendulum pounding-tuned mass damper (SPPTMD)—a novel nonlinear damping system comprising a spring pendulum (SP) and motion limiter that dissipates energy through spring resonance amplification and controlled mass-limiter impacts—was theoretically validated for structural vibration control. To experimentally verify its efficacy, a two-story, lightly damped steel frame was subjected to sinusoidal excitation and historical earthquake excitations under both uncontrolled and SPPTMD-controlled conditions. The results demonstrated (1) significant vibration attenuation through SPPTMD implementation and (2) enhanced control effectiveness in soft soil environments compared to stiff soil conditions. Additionally, a numerical model of the SPPTMD–structure system was developed, with computational results showing excellent correlation to experimental data, thereby confirming modeling accuracy. Full article

High-rise structures are normally tall and slender with a large height-width ratio. Under the strong seismic action, such a structure may experience violent vibrations and large deformation. In this paper, a spring pendulum pounding tuned mass damper (SPPTMD) system is developed to reduce the seismic response of high-rise structures. This SPPTMD system consists of a barrel limiter with the built-in viscoelastic material and a spring pendulum (SP). This novel type of tuned mass damper (TMD) relies on the internal resonance feature of the spring pendulum and the collision between the added mass and barrel limiter to consume the energy of the main structure. Based on the Hertz-damper model, the motion equation of the structure-SPPTMD system is derived. Furthermore, a power transmission tower is selected to evaluate the vibration reduction performance of the SPPTMD system. Numerical results revealed that the SPPTMD system can effectively reduce structural vibrations; the reduction ratio is greater than that of the spring pendulum. Finally, the influence of the key parameters on the vibration control performance is conducted for future applications. Full article

Piping systems are important nonstructural components of most types of buildings. Damage to piping systems can lead to significant economic losses, casualties, and interruption of function. A survey of earthquake disaster sites shows that suspended piping systems are flexible and thus prone to large deformation, which can lead to serious damage of the piping systems. The single-sided pounding tuned mass damper (PTMD), which is an emerging vibration suppression tool, has the potential to serve as a cost effective and non-invasive solution for the mitigation of vibration in suspended piping systems. The operating frequency of the single-sided PTMD can be tuned similarly to a tuned mass damper (TMD). The single-side PTMD also possesses high energy dissipation characteristics and has demonstrated outstanding performance in vibration control. One of the key factors affecting the performance of the PTMD is the damping material, and there is a constant search for the ideal type of material that can increase the performance of the PTMD. This paper explores the use of shape memory alloy (SMA) sponge as the damping material for two types (spring steel and pendulum types) of PTMDs to mitigate the vibration of a suspended piping system. The PTMDs are tested both in free vibration and in forced vibration. The results are compared with no control, with a TMD control, and with a viscoelastic (VE) material PTMD control. The results show that in free vibration tests, SMA–PTMDs attenuate the displacement of the piping system significantly. The time to mitigate vibration (i.e., reduce 90% of the vibration amplitude) is reduced to 6% (for spring steel type) and 11% (for pendulum type) of the time taken to mitigate vibration without control. In forced vibration tests, the overall magnitudes of the frequency response are also lowered to 38% (spring steel) and 44% (pendulum) compared to vibration without control. The results indicate that SMA has the potential to be a promising energy dissipating material for PTMDs. Full article

Suspended piping systems often suffer from severe damages when subjected to seismic excitation. Due to the high flexibility of the piping systems, reducing their displacement is important for the prevention of damage during times of disaster. A solution to protecting piping systems during heavy excitation is the use of the emerging pounding tuned mass damper (PTMD) technology. In particular, the single-sided PTMD combines the advantages of the tuned mass damper (TMD) and the impact damper, including the benefits of a simple design and rapid, efficient energy dissipation. In this paper, two single-sided PTMDs (spring steel-type PTMD and simple pendulum-type PTMD) were designed and fabricated. The dampers were tested and compared with the traditional TMD for mitigating free vibration and forced vibration. In the free vibration experiment, both PTMDs suppressed vibrations much faster than the TMD. For the forced vibration test, the frequency response of the piping system was obtained for three conditions: without control, with TMD control, and with PTMD control. These novel results demonstrate that the single-sided PTMD is a cost-effective method for efficiently and passively mitigating the vibration of suspended piping systems. Thus, the single-sided PTMD will be an important tool for increasing the resilience of structures as well as for improving the safety of their occupants. Full article