Active Control of Low-Frequency Sound Transmission Using Force Radiation Modes: A Numerical Study

Active control is a highly effective method for mitigating low-frequency noise transmission. To address the coupling effect and practical implementation challenges associated with conventional active control methods, a specific strategy for active control of noise transmission is developed. By leveraging an intuitive representation of transmitted sound power through force radiation modes, the control forces are designed such that the total excitation force vector becomes orthogonal to each dominant force radiation mode. Detailed theoretical development and case studies are presented. The research results indicate that decoupled control of transmitted sound power corresponding to each force radiation mode can be achieved, and excellent control outcomes can be obtained in both oblique incident and diffuse field applications. Further investigations reveal that the noise transmission can be effectively reduced, while the total vibration attenuation on the plate may not be assured, which depends on the relationship that exists between dominant force radiation modes and corresponding structural modes.