  Fiber bundles with statistically distributed thresholds for breakdown of
individual fibers are interesting models of the static and dynamics of failures
in materials under stress. They can be analyzed to an extent that is not
possible for more complex materials. During the rupture process in a fiber
bundle avalanches, in which several fibers fail simultaneously, occur. We study
by analytic and numerical methods the statistics of such avalanches, and the
breakdown process for several models of fiber bundles. The models differ
primarily in the way the extra stress caused by a fiber failure is
redistributed among the surviving fibers.
