Dynamic fracture in high strength metals
When a crack grows through a material at a significant fraction of the material's
shear wave speed, say 0.3 or greater, the intertia of the material, interacting
with inelastic deformation at the crack tip causes the resistance to
further fracture, or fracture toughness, to increase. In work
done for Zehnder's Ph.D. thesis, working with Ares Rosakis,
we measured the dynamic fracture propagation toughness of 4340
steel at crack speeds up to 1200m/s. The experimental technique
used was the method of caustics, combined with high speed
photography. A sample high speed photograph is shown below.
![[Caustics Photo]](caustics.gif)
High speed photograph of caustic, or "shadow spot" images.
Last updated Thu Sep 28 18:39:30 EDT 1995
atz@msc.cornell.edu (Alan Zehnder)
Back to Zehnder group homepage