Active Lamb Wave Structural Damage Monitoring Method Based on Wave Disintegration

For active Lamb wave based structural health monitoring,the monitoring signal quality may be easily influenced by environmental parameters changes and human error.Lamb wave propagation characteristics and the active Lamb wave based structural damage monitoring technique are analyzed first.The wave packet disintegration method is used to obtain the damage scattering signal Lamb wave.When the structure is damaged,the structural Lamb wave responses include two parts.One part is the Lamb wave responses collected before the structure is damaged,and it is called health structural responses.The other part is the signals scattered by the damages.Through the correlation operation,the health structural responses signals can be disintegrated from the current structural Lamb wave responses.The part remained will be the damage scattering signals if the structure is damaged.The basic principle and implementation process of the method are given.This method is verified by experiments in which a real glass epoxy composite plate structure is monitored.Time reversal damage imaging method is used to show the damage monitoring results.At the same time,the method is compared with traditional damage scattering signals collection method.Experimental results show that the proposed method can eliminate the impact of environmental parameters changes,and has better practicability.