Abstract:

The fatigue crack growth under the random loads is described by a time discrete Markoff process. The distribution function of crack length at given time can be calculated by integration of the initial crack length distribution and the transition function of Markoff process. The transition function can be identified with experience crack growth data. The structure reliability is calculated by intersection of the probability density function of crack length and distribution function of critic crack length. A time-dependent reliability model accounting the crack inspected probability for inspectable structure is established.

Key words: reliability of structure, fatigue crack growth, Markoff process