Thursday, October 12, 2006
This is a blog to discuss the physics of slow fracture. "Slow" means that in general we are looking at the failure of materials where the typical timescale is not that related to the sound speed, but something "slower".
Fracture is fun for a number of simple reasons. Tear a piece of paper: the two sides of the fracture line are rough. In fact it appears that the statistics of the surfaces of the two pieces can be described with self-affine fractal language: why is one big question. Then one can hear distinct crackling sounds or noise. This can be measured, to discover that there is again a hidden "power-law" as there is in self-affinity. Now the power-law measures the probability of acoustic event (the noise) having a certain energy: this is related to a probability distribution without a characteristic scale, and it is summarized by the "power-law exponent" which all is similar to the Gutenberg-Richter law of earthquake magnitudes. Why this kind of intermittent response exists in many materials is an excellent problem, both for a physicist and for the materials scientist.
We have recently published a review article on this subject, and the reference is M.J. Alava, P.K.V.V. Nukala, and S. Zapperi, Advances in Physics 55, 349-476 (2006). A web-version can be found from the cond-mat physics preprint archive.
Fracture is fun for a number of simple reasons. Tear a piece of paper: the two sides of the fracture line are rough. In fact it appears that the statistics of the surfaces of the two pieces can be described with self-affine fractal language: why is one big question. Then one can hear distinct crackling sounds or noise. This can be measured, to discover that there is again a hidden "power-law" as there is in self-affinity. Now the power-law measures the probability of acoustic event (the noise) having a certain energy: this is related to a probability distribution without a characteristic scale, and it is summarized by the "power-law exponent" which all is similar to the Gutenberg-Richter law of earthquake magnitudes. Why this kind of intermittent response exists in many materials is an excellent problem, both for a physicist and for the materials scientist.
We have recently published a review article on this subject, and the reference is M.J. Alava, P.K.V.V. Nukala, and S. Zapperi, Advances in Physics 55, 349-476 (2006). A web-version can be found from the cond-mat physics preprint archive.
