Theoretical foundations of ultrasonic nondestructive testing of multilayer articles manufactured from composites with rubbery coatings: II. Scattering of elastic waves at flaws involving poorly glued joints between plastic layers and between a plastic layer and a rubbery coating

The second part of this study is devoted to the solution of the following problems: (i) excitation of plate modes with a lumped force applied to the plate's surface, (ii) scattering of a bending wave at a small crack parallel to the plate's surface, and (iii) scattering at a flaw involving a poorly glued joint between a rubbery coating and a plastic layer. The final formulas and numerical dependences for calculating the parameters of a crack or a cleavage are presented. A mathematical model that describes the scattering of waves by flaws in a multilayer article made from a plastic composite material has been developed.