Low frequency vibration reduction of CFRP raft frame based on local resonance

As the demand for enhanced ship stealth performance continued to grow, the need for effective vibration isolation in the floating raft frame system, particularly within the low-frequency range, was increased. The raft frame played a critical role in determining the overall vibration-reduction performance. To improve the low-frequency vibration reduction, this paper incorporated the low-frequency elastic wave modulation characteristics of local resonance and the high damping properties of Carbon Fiber Reinforced Plastics (CFRP) into the raft frame, investigating their vibration characteristics via a test platform. Different oscillator distributions and masses were applied to the CFRP raft frame to study their effects on vibration behavior, with measurements taken using the B&K test system. The results revealed that the addition of oscillators lowered the initial vibration attenuation frequency and increased the maximum vibration attenuation from 48.9 dB to 103.2 dB. Optimal vibration reduction was achieved by placing the oscillators at the support position for low-frequency attenuation and at the center position for high-frequency attenuation. This spatial distribution strategy demonstrated agreement with simulation predictions. In conclusion, integrating the low-frequency modulation characteristics of local resonance into the CFRP raft frame significantly enhanced its vibration-reduction performance.