title: Cracks faster than the shear wave speed
abstract: Classical dynamic fracture theories predict the surface wave speed to be the limiting speed for propagation of in-plane cracks in homogeneous, linear elastic materials subjected to remote loading. This report presents experimental evidence to the contrary. Intersonic shear-dominated crack growth featuring shear shock waves was observed along weak planes in a brittle polyester resin under far-field asymmetric loading. When steady-state conditions were attained, the shear cracks propagated at speeds close to 2 times the material shear wave speed. These observations have similarities to shallow earthquake events where intersonic shear rupture speeds have been surmised.
authors.affiliation: Graduate Aeronautical Laboratories, California Institute of Technology, Pasadena, CA 91125, USA.
authors.initials: AJ
authors.lastname: Rosakis
authors.initials: O
authors.lastname: Samudrala
authors.initials: D
authors.lastname: Coker