Egative Stiffness News Today

As the operation speed of high-speed train increases, trains with fixed suspension stiffness will encounter dramatical vibrations, especially when its lateral resonance occurs. This greatly affects the ride comfort and safety of the trains. Based on this motivation, a novel stiffness variable suspension system using magnetorheological elastomer (MRE) isolator with negative stiffness is proposed. The controllable stiffness can make the train avoid lateral resonance while the negative stiffness ch...

This paper proposed and prototyped a metamaterial isolator with periodic structure based on magnetorheological elastomer (MRE) and magnet spring. With acoustic metamaterial structure, the proposed metamaterial isolator can generate a stop-band, which means the vibration over specific frequency can't be transferred and will be isolated effectively. Then, with the control of MRE stiffness, the cut-off frequency of the stop-band is tunable, which makes the isolator potential to be adapted to d...

Inspired by the strong nonlinearity of origami cartons, a novel origami-inspired constant-force mechanism (OriCFM) is systematically studied for obtaining a stable quasi-static constant force output. The proposed OriCFM is evolved by adding equivalent springs at horizontal and oblique creases of the rigid origami mechanism. Based on the geometry relationship, the mechanical model of the origami carton is established and its zero-stiffness is obtained. The influence of structural parameters and s...

The group of active suspensions with controllable actuating force is noted with their excellent performance in reducing vibrations, however, their demanding requirements for high power consumption and high cost as well as the highly potential instability issue have hindered their practical usage. Semi-active suspensions with controllable stiffness or damping are simple, stable and cost-efficient, but they cannot provide equivalent performance with active suspensions. By incorporating the negativ...