October 23, 2007
Replaces November Meeting
5:30 Social Hour
6:30 - 7:30 Dinner
7:30 - Speaker : Ted L Anderson, Ph.D., P.E.
Recent Advances in Fracture Mechanics and Fitness-for-Service Assessment
Fracture mechanics, as an engineering discipline, dates back to the 1950s. Over the years, this field has blossomed, both in terms of technological advances and widespread adoption. Fitness-for-service (FFS) assessment is a relatively new branch of engineering that encompasses fracture mechanics along with a variety of other disciplines. As the name suggests, fitness-for-service assessment determines whether or not equipment that contains flaws or other damage is fit for continued service. By avoiding catastrophic failures, unplanned shutdowns, and unnecessary repairs, FFS assessment can save enormous sums of money. In 2000, the American Petroleum Institute published API 579, a comprehensive guide for FFS assessment of pressure equipment. In the summer of 2007, a revised version of this procedure was published jointly by API and ASME. The new API/ASME FFS standard has a broader industry focus than the 2000 edition of API 579, and it incorporates recent technological advances.
Fracture mechanics and FFS analyses have traditionally relied on simplified models for the behavior of structural components with flaws. Weld residual stresses, for example, usually have been set equal to the yield strength of the material because reliable information on actual residual distribution was simply not available. With advances in computer technology, however, such simplified models are no longer necessary. More realistic models for materials and structures are now feasible. This presentation will include examples of the following state-of-the-art analyses:
- Simulation of multi-pass welding to determine residual stresses.
- 3D modeling of cracks and other flaws in structural components.
- Finite element modeling of fatigue crack growth.
- Simulation of dynamic fracture.
