Crack propagation and stick-slip dynamics arising from solid friction w be experimentally studied from the point of view of nonlinear science. Two setups are now available: a system for measuring several physical magnitudes in the cracking of brittle materials, and a device for monitoring velocity and torque of two surfaces rubbing against each other.
Dynamical properties of cracks (such as propagation velocity, surface profiles and sound emission) will be studied in order to find correlations among them, and their influence in the development of the instability. Experiments on solid friction should help to explain complex statistics of the system, such as the amplitude distribution of events, in terms of simple dynamics.
In both cases, direct comparison with existing theoretical results will be possible. It has been suggested that crack propagation is a case of directed percolation, and predictions from numerical models of stick-slip dynamics are already available.