A novel crack size quantification method based on lamb wave simulation

In recent years, Lamb wave has shown great potential in structural integrity assessment and life prediction due to the capability of traveling at large distances in structures with little energy loss. However, most of existing researches of Lamb wave based damage detection mainly focus on specific target systems. Physical models which correlate the crack size and damage sensitive features may vary with different structural geometry, loading profile et al. Therefore, it is of significant interest to develop a general methodology for reliable, efficient and accurate crack quantification for different structures. This paper presents a crack size quantification method based on finite element simulation. Lamb wave propagation mechanism is studied by Abaqus simulation. A series of simulations of both healthy plate and plates with different crack sizes are performed using Abaqus CAE. According to existing literatures, S0 mode of Lamb wave is sensitive with crack damage. Thus first wave package of S0 mode is chosen to extract damage features from measured time series. Two damage sensitive features: normalized amplitude and correlation coefficients are identified by analyzing simulation results and employed to establish a crack size quantification model. Considering the uncertainties caused by different manufacturing and environmental conditions, series of coupon tests are performed and the same damage sensitive features of testing data are extracted. The effectiveness of the proposed crack size quantification method is verified by data of coupon test.