Optimal inspection planning and repair under random crack propagation

• Accurate stochastic polynomial chaos crack propagation model employed.
• Number of inspections is a design variable, leading to discontinuous objective function with multiple local minima.
• Critical crack size at which repair is performed is a relevant design variable.
• Optimal inspection schedules highly sensitive w.r.t. costs of inspection and failure.
• Optimal inspection schedules highly sensitive w.r.t. level of loading.

Operation of damage-tolerant structures or components subject to random crack propagation requires constant monitoring by non-destructive inspections and systematic maintenance actions. Optimization of inspection schedules and repair strategies is a compromise between costs of inspections and repairs, and expected costs of failure. This paper advances the state of the art by: considering accurate polynomial chaos model of the random crack propagation process; considering number of inspections and crack repair size as design variables and; by performing sensitivity analysis of optimal inspection schedules and repair strategies with respect to the assumed costs of inspection and failure, as well as to the level of loading.

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