Progressive phase trends in plates with embedded acoustic black holes

Area of Science:

• Mechanical Engineering
• Acoustics
• Materials Science

Background:

• Acoustic black holes (ABHs) are recognized for passive broadband noise and vibration control.
• Traditional damping metrics focus on maximizing structural damping loss factors.
• Achieving an input-output response akin to an infinite structure is a key goal for damping treatments.

Purpose of the Study:

• To experimentally investigate phase accumulation in finite plates with and without embedded ABH grids.
• To compare experimental phase accumulation data with theoretical models for finite and infinite uniform plates.
• To assess the effectiveness of ABH treatments in enhancing structural damping and mimicking infinite plate behavior.

Main Methods:

• Experimental measurement of vibration mobility transfer functions on finite plates.
• Embedding grids of acoustic black holes within the plates.
• Comparison of experimental phase accumulation with theoretical predictions for uniform and infinite plates.

Main Results:

• Embedded ABH treatments significantly enhanced the damping of the finite plates.
• Phase accumulation in ABH-treated plates closely matched the theoretical phase accumulation of infinite plates.
• The spatial dependence and limits of phase accumulation were examined and compared to theoretical estimates.

Conclusions:

• Acoustic black hole treatments effectively enhance structural damping in finite plates.
• ABH treatments enable finite structures to achieve vibration response characteristics of infinite structures.
• This study validates the use of ABHs for advanced vibration and noise control applications.