An Experimental Model of the Ultrasonic Wave Propagation Through a Doubly-Periodic Array of Defects

In the present chapter we consider both computer and natural experimental approaches for the wave propagation through an elastic material with the doubly-periodic system of holes. The numerical study is performed by applying the Boundary Integral Equation method with further discretization to the algebraic system by the Boundary Element Method. A wide range of numerical experiments is conducted for different setups of the doubly periodic system, varying distances, sizes of the holes and their locations. The influence of hole cross-sections on the wave-transmission coefficient is examined by considering different star-like shapes. Natural experiments are based on the ultrasonic testing performed for the steel and plastic materials with the system of small holes. The experimental data are analyzed from the point of their spectral characteristics as well as the amplitude-time dependence.