Energy dissipation studies of Mg-based nanocomposites using an innovative circle-fit approach

In the present study, energy dissipation capability of magnesium containing variable amounts of nanosize alumina (Al ₂O ₃) particle is investigated. Synthesis of materials was accomplished using a solidification processing route. Energy dissipation in the form of damping capacity was determined using a free-free type suspended beam arrangement coupled with a circle-fit approach. This technique is based on the classical vibration theory, by which the geometry and material properties of the metal matrix composites are related to resonant frequency and structural damping of the test specimen. Using the fact that the ratio of the vibration response to the applied force fits to a circle in the Argand plane for each resonant frequency of the test specimen, the damping factor and natural frequency is predicted accurately for the test specimen. The results revealed that an increase in the Al ₂O ₃ content upto 1.134 vol.% lead to an increase in the damping capacity upto 64%. Attempt is made to correlate the increase in damping with the increased volume fraction of nanosize Al ₂O ₃ particle in the composite samples.