Thermo-Elastic Dynamic Instability (TEDI)—a review of recent results

Frictional instabilities arise in a number of engineering and scientific contexts, when the presence of friction renders unstable the uniform motion between parts under nominally uniform conditions. Various classes of friction instabilities exist, those involving friction weakening with speed, and those at constant coefficient of friction. In the latter class, in turn, there are Dynamic Instabilities (DI) and Thermo-Elastic Instabilities (TEI). Recently, by including inertia terms in the formulations of the simple models already studied, the merging of TEI and DI has shown that, although the coupling of dynamic and thermal terms is generally weak (given the significant difference in the typical time scales of the two processes), thermal effects are capable of making otherwise neutrally stable dynamic modes unstable, rendering the new form of instability TEDI (ThermoElastoDynamic Instability) potentially interesting in a number of applications. Some results involving 1D and 2D models of TEDI are reviewed.