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CAN: an example of nonclassical acoustic nonlinearity in solids
I Yu Solodov1, N Krohn, G Busse
1Department of Physics, Moscow State University, Russia. isolodov@mail.ru
Ultrasonics
|August 6, 2002
Summary
Scientists discovered new nonlinear acoustic phenomena in solids. This contact acoustic nonlinearity (CAN) generates fractional subharmonics due to asymmetric interface stiffness, showing unique dynamic behaviors.
Area of Science:
- Solid Mechanics
- Acoustics
- Nonlinear Dynamics
Background:
- Nonlinear acoustic phenomena are crucial for understanding material behavior under stress.
- Nonbonded contact interfaces, like cracks, exhibit complex mechanical responses.
- Contact Acoustic Nonlinearity (CAN) describes nonlinear effects at interfaces.
Purpose of the Study:
- To investigate novel nonlinear acoustic phenomena at nonbonded contact interfaces in solids.
- To characterize the effects of asymmetric stiffness on acoustic wave propagation.
- To understand the mechanisms behind fractional subharmonic generation in cracked materials.
Main Methods:
- Simulating acoustic wave interaction with idealized and realistic nonbonded contact interfaces.
- Analyzing the asymmetric stiffness characteristics of interfaces under normal stress.
- Observing and measuring fractional subharmonic and higher harmonic generation.
Main Results:
- Observed a new class of nonlinear acoustic phenomena at cracked interfaces.
- Identified asymmetric interface stiffness as the cause of "nonclassical" effects.
- Demonstrated stiffness parametric modulation leading to fractional subharmonic generation.
- Documented threshold dynamic behavior, hysteresis, and instability in CAN.
Conclusions:
- Asymmetric stiffness in contact interfaces is a key factor in generating nonlinear acoustic effects.
- Contact Acoustic Nonlinearity (CAN) can lead to the generation of fractional subharmonics and higher harmonics.
- These nonlinear acoustic phenomena exhibit complex dynamic behaviors including hysteresis and instability.