Nonlinear Shear Waves for Structural Damage Detection – Crack-Wave Interaction Modelling and Numerical Simulations

The paper investigates ultrasonic nonlinear shear horizontal waves. The major focus of the work undertaken is on the fundamental mode due to its non-dispersive nature. Nonlinear crack-wave interaction is investigated. Local crack-induced nonlinear elasticity and dissipation are modelled using hysteresis. Numerical simulations of crack-wave interaction are performed using the Local Interaction Simulation Approach, allowing not only for top-down solution of nonlinear differential equations but potentially also for parallel computing architecture. Modelling and numerical simulations are undertaken to reveal various nonlinear phenomena. This includes not only higher harmonic generation but also nonlinear vibro-acoustic modulations. Numerical simulations demonstrate that cracks can be effectively represented using local models of hysteresis that have been previously used for modelling of distributed material nonlinearity.