Title of article :
Dynamic crack response to a localized shear pulse perturbation
in brittle amorphous materials: on crack surface roughening
Author/Authors :
D. Bonamy، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2005
Abstract :
Linear Elastic Fracture Mechanics (LEFM) provides a coherent framework to evaluate
quantitatively the energy flux released at the tip of a growing crack. However, the way in which the
crack chooses its path in response to this energy flux remains far from completely understood: the
growing crack creates a structure on its own as conveyed by crack surface roughening even in brittle
amorphous materials such as glass. We report here experiments designed to uncover the primary
cause of surface roughening in brittle amorphous materials. Therefore, we investigate the response of
a growing crack to local perturbation introduced as a shear wave pulse of controlled duration, amplitude,
frequency and polarization. This pulse is shown to induce a local mode III perturbation in the
loading of the crack front, which makes it twist locally, without fragmenting. This response is linear
both in amplitude and frequency with respect to the perturbation, and disappears with it. We also
show that shear wave pulses are emitted when the propagating crack encounters the heterogeneity.
Implications of these observations for possible sources of roughening are finally discussed.
Keywords :
Acoustic waves , Brittle fracture , crack front waves , Roughening , Wallner lines.
Journal title :
International Journal of Fracture
Journal title :
International Journal of Fracture