I³MS - Spatschek Seminar
Prof. Dr. Robert Spatschek - Stability and Failure of Frictional Interfaces: Generating Earthquakes on the Computer
Institute for Energy and Climate Research IEK-2, Research Center Jülich
Frictional processes are a natural feature of our daily life, yet their dynamics are not well understood. Recent experimental data have revealed that velocity strengthening friction, where frictional resistance increases with sliding velocity over some range, is a generic feature of such interfaces. Moreover, transitions between velocity weakening and strengthening regimes have recently been linked to slow fronts ("slow earthquakes"). Here we elucidate the importance of velocity strengthening friction by theoretically studying variants of a realistic friction model, all featuring identical logarithmic velocity weakening at small sliding velocities, but different high velocity behaviour. We find a dramatic influence on front velocity, event magnitude, dissipation and radiation rates. Additionally, we show that velocity strengthening can give rise to a new kind of frictional instability for sliding on a rigid substrate, which is related to interval vibrational high frequency excitations in the sliding object.