Vibration characteristics of mineral composite beams by experimental modal test method

Abstract

Some machines, such as heavy presses and rammers, can be exposed to big shock and inertial forces under dynamic severe working conditions. Even if vibration isolation to the foundations of machines operating under dynamic loads is applied, the exposure of these machines to shock and resonance loads may not be adequately prevented. The sensitivity of these machines, the product quality, or life span can also incredibly decrease. Therefore, it is essential to know the vibration behaviors of machine bodies and parts. This study investigates vibration characteristics of polymer matrix composite (PMC) materials by the experimental modal test method. Nine different composite beam samples having sizes of 20 x 25 x 480 mm were produced for modal tests. Composite beams contain different ratios of aggregate and epoxy resin. Each composite beam's natural frequencies and damping ratios were defined with frequency response and coherence functions taken from the experimental modal tests. The results from the modal analysis revealed that the most influential parameter on the vibration properties was the gravel ratio. As a result of the experimental study, it was concluded that while epoxy-resin, gravel and fine-sand additives increased the stiffness of PMC beam, gravel and fine sand additives also increased the damping rate of PMC beam.