Dynamic acousto-elastic test using continuous probe wave and transient vibration to investigate material...

Area of Science:

• Materials Science
• Non-Destructive Testing
• Solid Mechanics

Background:

• Material nonlinearity is crucial for understanding structural integrity under dynamic loads.
• Traditional methods for assessing material nonlinearity can be complex and time-consuming.
• Acousto-elastic effects offer a promising avenue for non-destructive evaluation of material properties.

Purpose of the Study:

• To demonstrate the feasibility of using the dynamic acousto-elastic effect for material nonlinearity investigation.
• To analyze material nonlinearity in concrete under transient vibration using a continuous high-frequency wave.
• To characterize relaxation mechanisms, including modulus and attenuation recovery, in hysteretic effects.

Main Methods:

• A continuous 500kHz high-frequency ultrasonic wave was propagated through a concrete sample.
• Transient vibration was induced via a precisely positioned hammer blow, modulating the ultrasonic wave.
• A short-time Fourier transform approach was used to compare reference and impact-modulated signals for nonlinear behavior extraction.

Main Results:

• The dynamic acousto-elastic effect successfully revealed material nonlinearity in the concrete sample.
• Hammer-induced impacts caused measurable phase shifts and amplitude variations in the ultrasonic signal.
• Analysis identified coupled fast and slow hysteretic effects through modulus and attenuation recovery mechanisms.

Conclusions:

• The dynamic acousto-elastic effect of a continuous high-frequency wave is a feasible method for investigating material nonlinearity.
• This technique enables discrete-time extraction of nonlinear behavior during transient vibrations.
• The study provides insights into the complex relaxation mechanisms governing hysteretic effects in materials like concrete.