Receiver calibration and the nonlinearity parameter measurement of thick solid samples with diffraction and...

Area of Science:

• Materials Science
• Acoustics
• Nonlinear Ultrasonics

Background:

• Accurate measurement of the nonlinearity parameter (β) is crucial for material characterization.
• Existing methods often require complex receiver calibration and corrections for diffraction and attenuation.

Purpose of the Study:

• To develop and validate an accurate analytical and experimental technique for determining the nonlinearity parameter (β) in thick solid samples.
• To address challenges in receiver calibration, beam diffraction, and material absorption effects.

Main Methods:

• A simplified self-reciprocity calibration procedure for broadband receivers was developed.
• Analytical derivations for diffraction and attenuation corrections for fundamental and second harmonics were performed.
• Finite amplitude, through-transmission method was employed using aluminum alloy samples of varying thicknesses (4-12 cm).

Main Results:

• The proposed technique successfully determined the nonlinearity parameter (β) in thick solid samples.
• Systematic investigation revealed the significant impact of diffraction and attenuation corrections.
• With proper corrections, the variation in β across different sample thicknesses was reduced to less than 3.2%.

Conclusions:

• The presented technique provides accurate nonlinearity parameter (β) measurements in thick solids.
• Accounting for diffraction and attenuation is essential for reliable ultrasonic material characterization.
• The method demonstrates robustness and consistency across various sample thicknesses.