Describes a probabilistic methodology for fracture assessments of flaw
ed structures constructed of ferritic steels using the research code W
STRESS. The probabilistic formulation for cleavage fracture implements
a multiaxial form of the weakest link model which couples the macrosc
opic fracture behavior with a micromechanics model based on the statis
tics of microcracks. The Weibull stress, sigma(w) emerges as a suitabl
e near-tip parameter to provide a connection between the microregime o
f failure and remote loading (J). WSTRESS builds on an iterative proce
dure to incorporate a 3-D finite element description of the crack-tip
stress field and measured values of fracture toughness to calibrate th
e Weibull modulus, m, and the scale parameter, sigma(u), Specific feat
ures of the code include statistical inference of Weibull parameters b
ased on uncensored and censored models (with maximum likelihood method
), construction of confidence intervals, several definitions for the n
ear-tip fracture process zone and other general facilities such spatia
l integration of the stress field (to incorporate the random orientati
on of microcracks) and stochastic simulation of fracture data using th
e Monte Carlo method. The code also includes a convenient free-form co
mmand language and a seamless interface with finite element results fi
les stored in Patran binary or ASCII format.