Acoustic Nonlinearity of Narrowband Laser-generated Surface Waves in the Bending Fatigue of Al6061 Alloy

Jhang, Kyung-Young; Nam, Tae Woon; Choi, Sungho; Lee, Taehun; Kim, Chung Seok

doi:10.3938/jkps.57.1212

Cited by 15 publications

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“…where the relative acoustic nonlinearity parameter (β ) is the magnitude of the second-order harmonic frequency component (A 2 ), divided by the squared magnitude of the fundamental frequency component A 2 1 [23,30,31,33].…”

Section: Experimental Setups For Acoustic Nonlinearity Measurement Usmentioning

confidence: 99%

“…By monitoring the variations in the acoustic nonlinearity, the changes in the microstructure can be nondestructively evaluated. Several theoretical [5,8,18,29] and experimental [4][5][6][8][9][10][12][13][14][15][16][17][18]20,[22][23][24][25][26][27][28][29][30] studies have shown that the acoustic nonlinearity parameter can represent a sensitive indicator in the NDE of the material degradations.…”

Section: Introductionmentioning

confidence: 99%

“…The NDE using a surface acoustic wave (SAW), also known as a Rayleigh wave, has many advantages in industrial applications [14,27,28,30,31] compared to bulk acoustic waves [5,7,10,14,15,18,22,23,25,29]. Since the SAW can be generated and received on only one side of the target, the NDE using the SAW is a powerful solution for the situations in which the accessible area is limited.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the NDE using the SAW is a feasible and promising candidate for inspecting large areas of complex structures. In order to measure the acoustic nonlinearity by using the SAW for the NDE of the material degradations, both contact [7,12,16,17,19,20] and non-contact [6,13,14,24,27,28,[30][31][32] methods have been studied. Although the generation mechanisms of the SAWs are different from each other, e.g., using a contact transducer or using a pulsed laser shot, the variation trend in the acoustic nonlinearity was measured similarly with respect to the material degradation [33].…”

Section: Introductionmentioning

confidence: 99%

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Nondestructive Evaluation of Thermal Aging in Al6061 Alloy by Measuring Acoustic Nonlinearity of Laser-Generated Surface Acoustic Waves

Jun

Seo

Jhang

2019

Metals

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The structures in high-temperature environments are prone to undergo hardening and embrittlement as a result of thermal aging; this can cause variations in their mechanical properties. Because these changes occur at the microstructural level, it is difficult to evaluate them through linear ultrasonic techniques. In this work, a surface acoustic wave (SAW) was used to measure and compare the acoustic nonlinearity and mechanical properties of Al6061 alloys heat-treated at 220 °C for different durations (0 min, 20 min, 40 min, 1 h, 2 h, 10 h, 100 h, 1000 h). The SAW was generated by a pulsed laser and then received by an interferometer. Moreover, the yield strength, ultimate strength, and elongation to failure were measured by tensile tests. The results demonstrate that the critical variations in the mechanical properties can be detected by monitoring the variation features in the acoustic nonlinearity. Transmission electron microscopy images were captured to observe the microstructural changes, which shows that the acoustic nonlinearity varied according to the change in the precipitation phase. This supports the acoustic nonlinearity measurement using the laser-generated SAW being an effective technique for the fully noncontact nondestructive evaluation of material degradations as well as changes in mechanical properties.

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Section: Experimental Setups For Acoustic Nonlinearity Measurement Usmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nondestructive Evaluation of Thermal Aging in Al6061 Alloy by Measuring Acoustic Nonlinearity of Laser-Generated Surface Acoustic Waves

Jun

Seo

Jhang

2019

Metals

Self Cite

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“…Nonlinear acoustic techniques are widely accepted for their higher sensitivity to the state of micro-structured and damaged materials, compared with linear acoustic techniques [14,[17][18][19][20][21][22]. In particular, recent studies had theoretically and experimentally confirmed that nonlinear acoustics was an effective and sensitive tool of nondestructive characterization for various thermally treated materials [17,[23][24][25][26][27][28][29][30][31][32][33][34]. In comparison with other wave modes used in nonlinear acoustics to detect thermal modification of material state, for example Rayleigh waves [32,[35][36][37][38][39] and Lamb waves [40][41][42][43], bulk waves [28,[44][45][46][47][48] were extensively utilized.…”

Section: Introductionmentioning

confidence: 99%

Monitoring of Thermal Aging of Aluminum Alloy via Nonlinear Propagation of Acoustic Pulses Generated and Detected by Lasers

Lomonosov

Shen

et al. 2019

Applied Sciences

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Nonlinear acoustic techniques are established tools for the characterization of micro-inhomogeneous materials with higher sensitivity, compared to linear ultrasonic techniques. In particular, the evaluation of material elastic quadratic nonlinearity via the detection of the second harmonic generation by acoustic waves is known to provide an assessment of the state variation of heat treated micro-structured materials. We report on the first application for non-destructive diagnostics of material thermal aging of finite-amplitude longitudinal acoustic pulses generated and detected by lasers. Finite-amplitude longitudinal pulses were launched in aluminum alloy samples by deposited liquid-suspended carbon particles layer irradiated by a nanosecond laser source. An out-of-plane displacement at the epicenter of the opposite sample surface was measured by an interferometer. This laser ultrasonic technique provided an opportunity to study the propagation in aluminum alloys of finite-amplitude acoustic pulses with a strain up to 5 × 10−3. The experiments revealed a signature of the hysteretic quadratic nonlinearity of micro-structured material manifested in an increase of the duration of detected acoustic pulses with an increase of their amplitude. The parameter of the hysteretic quadratic nonlinearity of the aluminum alloy (Al6061) was found to be of the order of 100 and to exhibit more than 50% variations in the process of the alloy thermal aging. By comparing the measured parameter of the hysteretic quadratic nonlinearity in aluminum alloys that were subjected to heat-treatment at 220 °C for different times (0 min, 20 min, 40 min, 1 h, 2 h, 10 h, 100 h, and 1000 h), with measurements of yield strength in same samples, it was established that the extrema in the dependence of the hysteretic nonlinearity and of the yield strength of this alloy on heat treatment time are correlated. This experimental observation provides the background for future research with the application goal of suggested nonlinear laser ultrasonic techniques for non-destructive evaluation of alloys’ strength and rigidity in the process of their heat treatment.

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A Pulse Inversion-Based Nonlinear Ultrasonic Technique using a Single-Cycle Longitudinal Wave for Evaluating Localized Material Degradation in Plates

Choi

Lee

Jhang

2019

Int. J. Precis. Eng. Manuf.

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Acoustic Nonlinearity of Narrowband Laser-generated Surface Waves in the Bending Fatigue of Al6061 Alloy

Cited by 15 publications

References 0 publications

Nondestructive Evaluation of Thermal Aging in Al6061 Alloy by Measuring Acoustic Nonlinearity of Laser-Generated Surface Acoustic Waves

Nondestructive Evaluation of Thermal Aging in Al6061 Alloy by Measuring Acoustic Nonlinearity of Laser-Generated Surface Acoustic Waves

Monitoring of Thermal Aging of Aluminum Alloy via Nonlinear Propagation of Acoustic Pulses Generated and Detected by Lasers

A Pulse Inversion-Based Nonlinear Ultrasonic Technique using a Single-Cycle Longitudinal Wave for Evaluating Localized Material Degradation in Plates

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