Investigation of Thermoelastic Modulation Phenomenon Due to Frictional Dissipation on Crack Interfaces

Interaction of an ultrasonic wave with a structural defect causes various types of physical phenomena, which in-depth description requires a multiphysical or even multiscale approach. Heat generation in the vicinity of a crack is one of these phenomena. Different theoretical models were developed to describe its features such as the local temperature rise due to the crack's surfaces mutual interactions, or the heat generated at the grain boundaries of polycrystalline materials. In this work, the coupled thermoelastic theory, analytically described by the heat-diffusion equation and Navier's equation of motion, is considered to investigate the ultrasonic wave behavior in a homogenous isotropic structure with local nonlinearity. The nonlinearity is modeled as a through-thickness crack with an implemented Coulomb friction model. Numerical simulations are used to analyze the influence of the heat dissipation at the crack on the propagating ultrasonic wave. In particular, an amplitude modulated shear horizontal wave is used to cause the local heat generation at the crack. This frictional interaction becomes a source of a thermal wave that perturbs the structure near the defect. The amplitude modulation transfer from the elastic to the thermal wave, and the influence of the normal force prescribed at the crack are addressed.

Automated summary

The interaction between ultrasonic waves and structural defects leads to various physical phenomena, one of which is heat generation near cracks. This study employs coupled thermoelastic theory to investigate the behavior of ultrasonic waves in a homogeneous isotropic structure with local nonlinearity, and numerical simulations are used to analyze the influence of heat dissipation at cracks on propagating ultrasonic waves.