Defect Localization Using Nonlinear Lamb Wave Mixing Technique

Structural health monitoring using nonlinear guided waves have found to be of great importance. The detection of micro/fatigue cracks in the early stage is essential to avoid catastrophic failures. This paper presents a defect localization technique using nonlinear interaction primary Lamb wave modes. The nonlinearity employed here is due to clapping behaviour of crack surfaces. Two counter-propagating Lamb waves with dissimilar frequencies are allowed to mix at various locations. The results show that the sensitivity of nonlinearity due to crack wave interaction increases when Lamb wave mixing occurs at the fault zone. To study the extent of nonlinearity on damage size, studies were also conducted on plates with different crack parameters. The study reveals that the nonlinear Lamb wave mixing technique can be used effectively to detect and localize micro-crack in plate-like structures.