Course
The exploitation of the properties of mechanical waves propagating in the interior and along the boundary of a deformable solid is the basis of fundamental achievements in science and engineering. To mention a few, in seismology what we currently know about the interior structure of the Earth is to a large extent drawn from the interpretation of earthquake recordings. In geophysics, mechanical waves are used to explore the depths of the Earth’s crust in search of oil and gas reservoirs or large geological cavities for CO2 storage. In seismic engineering, earthquake disasters are often caused by the amplification of ground motion which is a typical wave-related phenomenon. In civil, mechanical and aerospace engineering, ultrasonic techniques are used as non-invasive diagnostic tools for detecting defects of structural components and they are based on exploiting the properties of high-frequency surface and bulk mechanical waves. Lastly, when a high-speed train exceeds a critical velocity, shock mechanical waves are generated and they are conceptually similar to the ones sparked by a supersonic aircraft with all the implications for the vibrational impact induced in the surroundings of the railway line.
Despite the diversity of the aforementioned examples, also for the characteristic wavelengths, the underlying physics of the phenomena involved is the same and linked to various properties of mechanical waves. The mathematical modeling may be different owing to a variety of constitutive assumptions that may be employed to simulate material behaviour. Examples include one-constituent elasticity, viscoelasticity, and multi-component poroelasticity. However, steel, concrete, aluminum and even soils or rocks are still conventional deformable materials. Over the past thirty years or so, a new class of materials have made their appearance. They are the so-called engineered metamaterials as they are purposely designed to have properties that are not found in ordinary materials. For instance, seismic metamaterials can inhibit or manipulate the propagation of seismic waves over certain frequency bands. They are made of ordered assemblies of multiple elements constituting composite periodic structures. Wave phenomena such as the acoustic rainbow trapping, are artificially created in elastic metamaterials to protect constructions from the earthquake ground motion. The recent development of these innovative classes of materials introduces a new paradigm in engineering and science for the design of smart materials and structures.
The course aims at covering the above-mentioned variety of topics by treating them in a unified framework. It is trans-disciplinary and delivered by top specialists in their respective areas of research. The course is addressed to PhD students and scholars working in different yet interacting research fields of dynamics of continua including but not limited to geophysics, seismology, structural mechanics, geotechnical engineering, material science and applied mathematics.