Experimental Study of Determining the Dynamic Characteristics of a Composite Beam with the Addition of Elastomer Material

Abstract Resonance is a critical phenomenon in structural dynamics, occurring when a structure’s natural frequency coincides with an external excitation frequency, resulting in amplified vibrations and increased deflection that may lead to structural failure. Mitigating resonance requires a thorough understanding of the structure’s dynamic properties and the application of effective damping techniques. This study experimentally investigates the dynamic behaviour of a composite beam composed of a polymer matrix (70% polyester resin and 30% vinyl ester resin) reinforced with carbon and hemp fibers. To enhance vibration damping, elastomeric materials, such as neoprene and silicone rubber, are incorporated. The results indicate that carbon fiber reinforcement yields higher stiffness and natural frequency. In contrast, hemp fiber exhibits a superior damping ratio. Neoprene rubber contributes to increased structural stiffness, while silicone rubber demonstrates enhanced damping performance due to its viscoelastic characteristics. The appropriate selection of fiber reinforcement and the addition of elastomeric material to composite materials make them more effective in shifting the natural frequency and reducing the response amplitude. The selection of fiber-elastomer combinations is guided by specific design objectives: carbon fiber with neoprene rubber is suitable for applications requiring higher stiffness conversely, hemp fiber combined with silicone rubber is recommended for improved damping.