SAGA is used on fracture mechanics projects where a standard S-N curve approach is not considered appropriate. The fracture mechanics program is based on the Paris’ Law approach described in SSC-409, which evaluates the growth of external and internal crack types typically found in ship structures.
The loading that drives fatigue stress ranges is defined by a Weibull distribution of a stress range. This is calculated by loading and solving an FEA model. The model program allows us to investigate the effect of:
Finite Element Model stress ranges are used in SAGA to calculate a fracture damage ratio. The amount of cycles in a design event is presented as a ratio of the amount of cycles to failure.