Cumulative second-harmonic analysis of ultrasonic Lamb waves for ageing behavior study of modified-HP austenite steel

Effect of tempering temperatures on nonlinear Lamb wave signal of modified 9Cr–1Mo steel

“…A "mountain shape" change in the second harmonic component of Lamb wave with thermal degradation was observed in FeCrNi alloy steels [17]. Cumulative second harmonic analysis of ultrasonic Lamb wave was performed to study the precipitation kinetics and micro-void initiation of modified HP austenite steel during aging [18]. Initial increase in normalized acoustic nonlinearity parameter due to fine precipitates followed by decrease due to precipitate coarsening and micro-void formation was observed in this study.…”

“…But, due to the inherent multi- [17][18][19][20]. A "mountain shape" change in the second harmonic component of Lamb wave with thermal degradation was observed in FeCrNi alloy steels [17].…”

Numerical studies of nonlinear ultrasonic guided waves in uniform waveguides with arbitrary cross sections

“…This pair has been widely investigated among researchers [16][17][18][19][20][21][22][23][24][25][26] for nonlinear guided waves, as both phase and group velocity of the primary mode match with the secondary mode and therefore easier for the signal post processing. The schematic of the plate model used for the simulation is shown in Fig.…”

“…waves, [16][17][18] evaluation of incipient damages (creep, 19 fatigue [20][21][22] and plasticity 23,24 ) in plate like structures, investigation of the material decay, 25,26 as well as assessment of thermal fatigue damages in isotropic pipes. 27 However, most studies on nonlinear ultrasonic guided waves are limited to simple geometries, such as plates, rods or pipes.…”

Creep degradation characterization of titanium alloy using nonlinear ultrasonic technique

“…Therefore, it is of increasing importance to establish an effective non-destructive characterization method of creep degradation at early stage for structural health monitoring (SHM). In recent years, it is noted that nonlinear ultrasonic technique, using the amplitude ratio of primary frequency to higher harmonic frequencies, has been found to be considerably sensitive to microstructure evolution of materials [5][6][7][8][9][10][11][12][13][14][15].…”