Homogeneous and sandwich active panels under deterministic and stochastic excitation

Area of Science:

• Acoustics
• Structural Dynamics
• Materials Science

Background:

• Smart panels offer potential for noise and vibration control.
• Previous research focused on lower frequencies, limiting applicability.
• Understanding high-frequency behavior is crucial for advanced applications.

Purpose of the Study:

• To predict the structural response and sound radiation of smart panels using an element-based model.
• To investigate the effectiveness of decentralized velocity feedback control on aluminum and composite sandwich panels.
• To analyze panel behavior under diverse acoustic excitations, including plane waves, diffuse fields, and turbulent boundary layers, up to the upper audio frequency range.

Main Methods:

• An element-based computational model was employed.
• Two panels were analyzed: aluminum and a lower-mass composite sandwich panel.
• Decentralized velocity feedback control loops with idealized point force actuators were implemented.
• Simulations covered excitation by acoustic plane waves, stochastic diffuse fields, and turbulent boundary layers.

Main Results:

• Considerable reduction in structural response and sound radiation was predicted at low audio frequencies, particularly for well-separated low-order structural modes.
• The upper audio frequency range showed strong dependence on excitation field characteristics and panel radiation properties relative to bending wavelength.
• Some noise reduction was observed near acoustic and convective coincidence regions.

Conclusions:

• Decentralized velocity feedback control is effective in reducing structural response and sound radiation from smart panels, especially at lower audio frequencies.
• The study highlights the importance of excitation field characteristics and panel properties at higher frequencies.
• The findings provide valuable insights for designing advanced acoustic and structural control systems.