Continuous carbon fiber composites with enhanced mechanical energy dissipation (vibration damping) under flexure are provided by incorporation of fillers between the laminae. Exfoliated graphite (EG) as a sole filler is more effective than carbon nanotube (SWCNT/ MWCNT), halloysite nanotube (HNT), or nanoclay as sole fillers in enhancing the loss tangent, if the curing pressure is 2.0 (not 0.5)...

a r t i c l e i n f o a b s t r a c t A shunted piezoelectric is a device to suppress vibration consisting of a piezoelectric material and a shunt circuit connecting between two electrodes of the piezoelectric material. The sensitivity of damping performances is analyzed for passive shunted piezoelectrics: a resistive, a series resonant, and a parallel resonant shunted piezoelectric. The parame...

Passive damping plays an important role in the vibration mitigation of aeronautic structures. In contrast to active systems, passive systems do not require any energy supply. Thus, their readiness is independent, which reduces failure probability compared systems. Constrained Layer Damping (CLD) has become established treatment for bending vibrations. Unlike other such as shock-mounts, CLD can ...

Recent studies suggest that fruit flies use subtle changes to their wing motion to actively generate forces during aerial maneuvers. In addition, it has been estimated that the passive rotational damping caused by the flapping wings of an insect is around two orders of magnitude greater than that for the body alone. At present, however, the relationships between the active regulation of wing ki...

This paper presents a versatile and robust algorithm for the optimal design of adjacent structural systems linked by passive energy dissipation devices. The algorithm works both with stationary and nonstationary force input. It is a two-stage design procedure that (i) determines an active control law, and then (ii) adds damper and stiffness coefficients that are computed based on the minimizati...

The development and applications of a supplemental viscous damping device with active capacity are described. The system of the dampers de ned as active viscous damping system (AVDS) is presented herein. Structural control principles de ned here as active control theory (ACT) are used to obtain the control forces at each time step during an excitation. Control of the damping forces is possible ...

The superconducting magnetically levitated transport (Maglev) system is conceptualized as a next-generation high-speed transportation system. For practical use, it is important to achieve adequate ride comfort particularly in high-speed running. Maglev vehicles are composed of lightweight car bodies and relatively heavy bogies which are mounted with devices such as superconducting magnets (SCMs...

In this paper, dynamic analyses and field measurements of a tied arch railway bridge is presented. Excessive vibrations of the hangers were obtained, caused by resonance during train passages. The resulting increase of the stress level and number of stress cycles were shown to decrease the fatigue service life significantly. The most critical section is a threaded turnbuckle connection of the h...

The purpose of this study was to determine viscous properties of human muscle during plantarflexion efforts. Experiments were performed on 17 subjects with an ankle ergometer allowing sinusoidal oscillations during isometric contractions and isokinetic movements. Sinusoidal oscillations led to the expression of (i) Bode diagrams of the musculo-articular system allowing the determination of a da...

Switching power converters are widely used due to their excellent efficiency, but they inherently generate ripple. Passive low-pass LC filters have been traditionally employed to meet ripple and EMI specifications [1]. These passive filters can contribute considerably to the volume and weight of a power converter. In particular, capacitors can become relatively large in order to meet strict rip...