Broadband radiation modes: estimation and active control.

Area of Science:

• Acoustics
• Vibration Analysis
• Control Systems Engineering

Background:

• Efficiently radiating vibration patterns, known as radiation modes, are crucial for understanding and controlling sound emission from vibrating bodies.
• Current methods often focus on specific frequency ranges, limiting broadband applicability.
• Reducing controller dimensionality is essential for practical implementation in feedback control systems.

Purpose of the Study:

• To formulate broadband radiation modes in the time domain for efficient vibration control.
• To develop methods for obtaining these modes from measured data.
• To design and compare actuator array strategies for reducing radiated sound power from a plate using broadband radiation modes.

Main Methods:

• Formulation of broadband radiation modes in the time domain.
• Extraction of modes from measured vibration data.
• Design and comparison of three actuator array strategies for feedback control.

Main Results:

• The proposed broadband radiation modes enable efficient weighting schemes for sensor arrays.
• The methods allow for the determination of these modes from experimental measurements.
• Actuator designs were evaluated based on radiated sound power reduction across controlled and uncontrolled frequency ranges.

Conclusions:

• Broadband radiation modes offer an optimal approach for controlling radiated sound power over a wide frequency range.
• The developed methods facilitate the practical application of these modes in vibration control systems.
• Careful actuator design is necessary to balance sound power reduction in target bands with potential increases in other bands.