Fluidic flexible matrix composite damping treatment for a cantilever beam

This paper presents a novel approach for damping the vibration of a cantilever beam by bonding multiple fluidic flexible matrix composite (F²MC) tubes to the beam and using the strain induced fluid pumping to dissipate energy. Transverse beam vibration strains the F²MC tube and generates fluid flow through an energy dissipating orifice. An optimally sized orifice maximizes energy dissipation, greatly reducing the resonant peaks and increasing modal damping. An analytical model is developed based on Euler-Bernoulli beam theory and Lekhnitskii's solution for anisotropic layered tubes. Using miniature tubes, a laboratory-scale F²MC-integrated beam prototype is constructed and experimentally tested. The experimental results agree well with the theoretical predictions, provided the fluid bulk modulus is reduced to reflect the entrained air in the fluidic circuit. Based on the validated model, a design space study calculates the modal damping for various tube attachment locations and the orifice sizes. The results show that damping ratios of 32percent and 16percent are achievable in the first and second modes of a cantilever beam, respectively, using an F²MC damping treatment.