Active Constrained Layer Damping of Beams With Natural Fiber Reinforced Viscoelastic Composites

Viscoelastic composite reinforced with naturalfibers is proposed here for the dampingtreatment of structures for vibration attenuation. The constrained layer damping (CLD)method is found a prominent structural vibration damping method and as a result of theinclusion of naturalfiber, substantial damping could be achieved due to the developmentof shear as well as extensional strains in the viscoelastic material. Finite element analysisof a substrate beam combined with CLD treatment is used to investigate the correspondingimprovement in damping. The influence of various geometry of presently considered naturalviscoelastic composite layers on the CLD treatment's damping performance has been eval-uated and discussed. Damping performances of natural as well as syntheticfibers have beenassessed and compared for using naturalfibers in viscoelastic composite for various struc-tural applications. The addition of naturalfiber has resulted from enhanced dampingcapacity due to substantial friction at the naturalfiber-matrix interface compared to thecase of interface with syntheticfiber. Naturalfiber attributes less stiffness and a higherloss factor as compared to syntheticfiber and the insertion of stifffibers affects thepolymer chain's movements, decreasing the matrix phase's damping behavior. Thedynamic mechanical analysis test is performed to evaluate the damping characteristics inthe form of loss factor, storage, and loss modulus over the temperature range fromfrozen state to melting state.