System and method for passive damping of mechanical vibrations

A system for passive damping of mechanical vibrations generated by a vibrating structure supported by a support, the system comprising a transducer interposed between the vibrating structure and the support to transform the mechanical energy of the vibrations into electrical energy,

• wherein:
• the transducer includes:
• a flextensional structure having a first axis and a second axis perpendicular to each other,
• piezoelectric elements stacked along the first axis so as to form a piezoelectric stack, the piezoelectric stack is adapted to produce electrical energy when it is stressed, and the stack is stressed in compression by the flextensional structure along the first axis so that a deformation of said structure modifies the compressive stress applied to said stack,
• two peripheral fasteners are secured to the flextensional structure, each of the fasteners being disposed along the second axis,
• a first fastener for securing the flextensional structure to the vibrating structure,
• a second fastener for securing the flextensional structure to the support,
• at least one of the fasteners integrates an elastic suspension,
• said system further includes a means for modifying the electrical stiffness of the piezoelectric stack depending on a frequency band to be attenuated, the means comprising a shunt connected to said piezoelectric stack so as to dissipate all or part of the electrical energy produced by the stress applied to said piezoelectric stack;
• wherein the elastic suspension is an elastomer suspension, a metallic suspension, a pneumatic suspension, or a hydraulic suspension.