Adaptive lightweight CFRP strut for active vibration damping in truss structures

For the purpose of active damping and suppression of vibration in advanced composite truss structures a new adaptive lightweight strut was developed. It was based upon a previously developed multi-purpose CFRP sandwich strut with integrated load transfer elements. Into this strut. which exhibits excellent mechanical properties related to the structural weight. a piezoceramic high-load stack actuator with an expansion capability of 55 mu m was integrated. A spacial design using a composite sleeve allows the tailoring of the strut stiffness particularly with respect to high active tension forces. The measurement of the dynamic strut response is provided by a surface bonded and electrically isolated PVDF film sensor. Tests of the adaptive strut in an antenna-supporting composite truss structure established a nearly complete suppression of externally excited disturbing vibrations. Due to the structural concept the new adaptive strut is well suited for active vibration control under high strength and stiffness requirements.