Atomistics of Tensile Failure in Fused Silica: Weakest Link Models Revisited

In weakest link models the failure of a single microscopic element of a brittle material causes the failure of an entire macroscopic specimen, just as a chain fails if one link fails. Pristine samples of glass, such as optical communications fiber, approach their ideal strength, and their brittle tensile failure has been described by this model. The statistics of weakest link models are calculable in terms of the statistics of the individual links, which, unfortunately, are poorly known. Use of the skewness of the failure distribution may permit simultaneous determination of the statistics of the individual weak links and of their number density, which indicates their physical origin. However, the applicability of weakest link models to real materials remains unproven.