Creep damage characterization using a low amplitude nonlinear ultrasonic technique

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].…”

“…A 200% change in β is observed as a function of creep fraction life, which clearly indicates that β is sensitive to damage accumulation during creep deformation. More recently, a low-amplitude nonlinear ultrasonic technique was employed by Balasubramaniam et al [10] for characterizing creep damage in copper. Their results show that the nonlinear responses are greater as creep damage accumulates and, among these nonlinear responses, the third harmonic is more sensitive to creepgenerated dislocations than either the second harmonic or static component nonlinear parameter.…”

“…These events will cause losses of coherency and material strength, and then give rise to a formation of micro-voids. All these microstructure evolution during creep loading process would produce a very clear nonlinear response in materials [4,[8][9][10]. Though recently some investigations have been made to study thermal ageing behavior in various heat-resistant alloys using nonlinear ultrasonic, there is a lack of information with respect to systematic work and analysis on precipitation kinetics study of creep damage in complex titanium alloy.…”

Characterization of annealing in polycrystalline copper using harmonic generation technique

“…Note that, nonlinearity parameter β is a measure used to quantify the distortion of acoustic waves [1,2,3]. The applicability of NLU for the characterisation of degradation due to fatigue damage [4,5,1,2,6,7,8,9,10], creep damage [11,12,3,13], radiation damage [14] and thermal damage [15,16] were studied by different research groups. Karthik et al [17,18] observed that nonlinearities generate static displacement component in addition to higher harmonic contents.…”

Experimental investigation on effective detection of delamination in gfrp composites using taguchi method

“…Thus, non-invasive damage evaluations are crucial to inspect the failure in composite materials for the purpose of ensuring the integrity of a structure. Over the last decades, ultrasonic techniques have been the most widely used non-destructive testing and evaluation (NDE&T) method to analyze the defects occurred inside a structure [5][6][7]. Through-transmission or pulse-echo techniques are applied in which the specimen under test is induced by ultrasonic pulses and the transmitted or reflected pulse is interpreted.…”