Stiffness evolution of granular layers and the origin of repetitive, slow, stick-slip frictional sliding

We demonstrate the frictional behaviors of steady state sliding, stick-slip, and repetitive, slow stick-slip sliding through a carefully-designed suite of laboratory experiments focused on exploring the role of loading system stiffness in controlling the frictional response to shear. We performed tests on sheared layers of baking flour, with three configurations of loading blocks made of steel and cast acrylic to achieve different stiffnesses....