TY - GEN
T1 - Nonlinear properties of Lamb waves under modulation of fatigue damage: Finite element simulation with experimental validation
AU - Hong, Ming
AU - Zhou, Chao
AU - Su, Zhongqing
AU - Cheng, Li
AU - Qing, Xinlin
PY - 2013/7/26
Y1 - 2013/7/26
N2 - Engineering structures under cyclic loads experience continuous accumulation of fatigue damage, deteriorating at an alarming rate. Most existing structural health monitoring (SHM) techniques use linear signal features, which may be unwieldy to the detection of fatigue damage in an initial stage. A dedicated finite element (FE) modeling technique for simulating nonlinear properties of ultrasonic Lamb waves under the modulation of fatigue cracks in metallic materials was established. Piezoelectric wafers were included in the model for exciting Lamb waves and capturing nonlinear characteristics. A nonlinearity parameter was constructed to calibrate the extracted wave nonlinear properties. Feasibility of the FE technique was experimentally validated, and the results showed satisfactory consistency in between, both revealing that (i) the developed FE modeling technique is able to faithfully simulate fatigue crack-induced nonlinear properties in Lamb waves, providing repeatable characterization for fatigue cracks; (ii) the defined nonlinear parameter decreases when the direct wave path offsets from the fatigue crack, nonlinearly subject to the offset distance from the crack to a sensing path; and (iii) a cumulative growth of the nonlinearity parameter against the wave propagation distance exists. All the observations enable quantitative characterization of micro-fatigue cracks using embeddable piezoelectric wafers, facilitating development of SHM technique with a capacity of quantitatively detecting damage small in dimension.
AB - Engineering structures under cyclic loads experience continuous accumulation of fatigue damage, deteriorating at an alarming rate. Most existing structural health monitoring (SHM) techniques use linear signal features, which may be unwieldy to the detection of fatigue damage in an initial stage. A dedicated finite element (FE) modeling technique for simulating nonlinear properties of ultrasonic Lamb waves under the modulation of fatigue cracks in metallic materials was established. Piezoelectric wafers were included in the model for exciting Lamb waves and capturing nonlinear characteristics. A nonlinearity parameter was constructed to calibrate the extracted wave nonlinear properties. Feasibility of the FE technique was experimentally validated, and the results showed satisfactory consistency in between, both revealing that (i) the developed FE modeling technique is able to faithfully simulate fatigue crack-induced nonlinear properties in Lamb waves, providing repeatable characterization for fatigue cracks; (ii) the defined nonlinear parameter decreases when the direct wave path offsets from the fatigue crack, nonlinearly subject to the offset distance from the crack to a sensing path; and (iii) a cumulative growth of the nonlinearity parameter against the wave propagation distance exists. All the observations enable quantitative characterization of micro-fatigue cracks using embeddable piezoelectric wafers, facilitating development of SHM technique with a capacity of quantitatively detecting damage small in dimension.
KW - Fatigue crack characterization
KW - Finite element method
KW - Lamb waves
KW - Nonlinear ultrasonics
KW - Structural health monitoring
UR - http://www.scopus.com/inward/record.url?scp=84880438987&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/KEM.558.195
DO - 10.4028/www.scientific.net/KEM.558.195
M3 - Conference article published in proceeding or book
SN - 9783037857151
T3 - Key Engineering Materials
SP - 195
EP - 204
BT - Structural Health Monitoring
T2 - 4th Asia-Pacific Workshop on Structural Health Monitoring
Y2 - 5 December 2012 through 7 December 2012
ER -