title: Microwave propagation and absorption and its thermo-mechanical consequences in heterogeneous rocks.
abstract: A numerical analysis in a two-component model rock is presented including the propagation and absorption of a microwave beam as well as the microwave-induced temperature and stress distributions in a consistent way. The analyses are two-dimensional and consider absorbing inclusions (discs) in a non-absorbing matrix representing the model of a heterogeneous rock. The microwave analysis (finite difference time domain - FDTD) is performed with values of the dielectric permittivity typical for hard rocks. Reflections at the discs/matrix interfaces and absorption in the discs lead to diffuse scattering with up to 20% changes of the intensity in the main beam compared to a homogeneous model rock. The subsequent thermo-mechanical finite element (FE) analysis indicates that the stresses become large enough to initiate damage. The results are supported by preliminary experiments on hard rock performed at 2.45 GHz.
authors: Montanuniversitaet Leoben, A-8700 Leoben, Franz-Josef-Strasse 18, Austria; Institute of Physics.
authors: R
authors: R
authors: Meisels
authors: Montanuniversitaet Leoben, A-8700 Leoben, Franz-Josef-Strasse 18, Austria; Institute of Mechanics.
authors: M
authors: M
authors: Toifl
authors: Montanuniversitaet Leoben, A-8700 Leoben, Franz-Josef-Strasse 18, Austria; Chair of Mining Engineering and Mineral Economics.
authors: P
authors: P
authors: Hartlieb
authors: Montanuniversitaet Leoben, A-8700 Leoben, Franz-Josef-Strasse 18, Austria; Institute of Physics.
authors: F
authors: F
authors: Kuchar
authors: Montanuniversitaet Leoben, A-8700 Leoben, Franz-Josef-Strasse 18, Austria; Institute of Mechanics.
authors: T
authors: T
authors: Antretter
keywords: Microwave analysis; Microwave heating; Microwave irradiation experiments; Rock damage; Thermally induced stresses