FEM modeling of ultrasonic vibrothermography of a damaged plate and qualitative study of heating mechanisms

Ultrasonic vibrothermography (UVT), or sonic infrared imaging, is a promising technique which excites ultrasonic elastic waves to locally stimulate defects on solid specimens and is typically applied in the aerospace and automotive industries. This technique allows for defect selective imaging using thermal waves generated by ultrasound waves. Energy dissipation mechanisms turn a dynamically loaded defect into a heat source, which is identified by a thermography system. In this paper finite element method (FEM) is implemented for simulation of vibrothermography and qualitative study of crack heating caused by internal and external energy losses. External loss is modeled by considering local friction between crack surfaces and internal loss (hysteresis) is modeled by taking into account viscoelastic and thermoelastic damping in the absence of plastic deformations. Defected plate specimens with edge crack and internal crack subjected to ultrasonic waves are modeled and studied.