Vibration damping behavior of the thermoplastic composite beams

Continuous fiber-reinforced thermoplastic composites attract the attention of all kinds of vehicle manufacturers, especially automotive. In addition to their high specific strength and high specific stiffness as in conventional composites, it is important to determine their behavior in terms of vibration damping as a result of the viscoelastic and viscoplastic properties of the thermoplastic matrix material. Vibration damping behaviors of thermoplastic composite structures were investigated by experimental and Finite Element Analysis method within the scope of the master thesis. A steel beam sample and a beam sample made of 45% continuous glass fiber reinforced polypropylene composite material by volume were used to examine the vibration damping behaviors. Modal tests were carried out with the impact hammer method on cantilever beam specimens, one end of which is fixed and the other end is free. As a result of the tests, the first 3 natural frequency modes of the beams were examined. The data obtained by the finite element analysis method were compared with the test data. The dynamic damping ratios of steel and composite beam samples were calculated based on the data obtained from the modal analysis tests with the impact hammer method. As a result of the calculations, the dynamic damping ratio of the steel beam was found to be 0.012 and the dynamic damping ratio of the composite beam to be 0.02068.