Higher-order structural theories for transient analysis of multi-mode Lamb waves with applications to damage detection

Addressing the need for more computationally efficient and accurate simulation tools for Lamb wave-based structural health monitoring (SHM) systems, this paper proposes the use of refined theories for the study of the wave propagation phenomena in thin-walled structures. When dealing with complex structures, classical plate models can be insufficiently accurate whereas 3D finite elements soon reach their limits due to the high computational requirements in ultrasonic wave analysis. As a solution to these issues, a finite element framework based on the Carrera's unified formulation (CUF) is presented for the simulation of Lamb waves in continua. Different structural theories are discussed and tested, showing that the Lamb modes can be well represented using beam elements with enriched kinematics. The validity and convergence rates of the proposed models are assessed through benchmark solutions. An example of damage detection in a typical reinforced panel is included to show the potential of the method.