The Laboratory of Ultrasonic Methods (LUM) deals with both experimental and theoretical research in the field of Mechanics of Materials:
- Acoustic (ultrasonic) wave propagation in anisotropic/nonlinear/damping materials, materials with microstructure, phase transforming materials near the stability limits, materials with thin coatings and layers (down to the nanoscale), and other advanced materials or materials with unique acoustic/elastic properties
- Eigenvibrations, resonant spectra, or waveguide effects of samples of these materials (small single crystals, wires, plates)
- Kinematics and dynamics of movable martensitic microstructures and phase boundaries, both stress and temperature induced, spontaneous formation of interfacial microstructures, relations between the microstructure and the macroscopic dynamic properties.
- Any other dynamic effects inside the advanced materials which are observable (or can be induced or controlled) by use of ultrasound or other dynamic loading, such as dynamic damage (fracture, fatigue, britteling), dynamic phenomena in the microstructure (if they have direct influence on the macroscopic properties), internal friction etc.
All of the above listed phenomena exhibit strong thermomechanical coupling (i.e. coupling between mechanics and thermal effects) and their investigation requires advanced experimental techniques as well as multi-scale mathematical models. Their use for evaluation of thermomechanical properties of the examined materials (i.e. their elastic constants) usually requires complex and ill-posed inverse problems to be solved and Monte-Carlo simulations to be performed in order to obtain realistic estimation of experimental errors.
The particular issues studied in LUM include:
- Determination of elastic properties of single crystals and composite materials based on inversion of acoustic wave velocity fields
- Resonant Ultrasound Spectroscopy (RUS) investigation of single crystals and twinned structures of ferroelastics (determination of elastic properties and their thermal dependences)
- Experimental observation and theoretical analysis of martensite-to-austenite interfacial microstructures in shape memory alloys (SMA) propagating in a thermal gradient
- Experimental study of anharmonicity of movable martensite-to-austenite interfacial microstructures in SMAs
- Quasi-static and dynamic testing of SMA thin wires and textiles in combined loading modes
- Magneto-elastic attenuation of ultrasonic waves in magnetic SMAs
- Interaction of ultrasound with thin diamond coatings and layered structures and its use for nondestructive evaluation of these nano-scale structures
- Mathematical modeling of thermomechanical behaviour of phase transforming materials
- Development of design tools based on FEM for SMA's engineering and medical applications
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