Coupling of Highly Nonlinear Waves with Linear Elastic Media

This paper reports a fundamental study of the coupling between highly nonlinear waves, generated in a one dimensional granular chain of particles, with linear elastic media, for the development of a new Non Destructive Evaluation and Structural Health Monitoring (NDE/SHM) paradigm. We design and use novel acoustic actuators to excite compact highly nonlinear solitary waves in a one-dimensional linear elastic rod and investigate the pulse propagation across the interface. To model the actuator and rod system we use Finite Element Analysis (Abaqus) and obtain excellent agreement between the experimental observations and the numerical results. We also study the response of the system to the presence of defects (cracks) in the steel rod, by comparing the wave propagation properties in pristine and cracked test objects. The obtained results encourage the use of highly nonlinear waves as an effective tool for developing a new, viable NDE/SHM method.