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Stability
Failure under Tensile Stress
·Failure of brittle material usually contains two stages:
·Crack initiation (crack starts from zero),
·Crack propagation (crack grows to its full size).
·For thick brittle material:
·Cracks immediately propagate to full size after
initiation.
·Failure is governed by the number and size of the
defects.
·For thin brittle material:
·Cracks keep their lengths after initiation before
propagation starts.
·Failure is governed by how cracks propagate.

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