Probabilistic Fracture Mechanics

A Two Day Course
No Date Scheduled

Deterministic fracture mechanics analyses typically produce conservative results, since limiting assumptions must be made for key parameters. Some key parameters, however, are known to vary significantly, and can be assumed to behave in a random manner. For example, both material fracture toughness and weld residual stress have been found to demonstrate significant scatter based on actual measurements.

Fundamental Concept in Fracture Mechanics

The Monte Carlo probabilistic analysis approach has been used extensively in highly complex, probabilistic assessments in various industries. The essence of this approach is to assign mean values and statistical distributions to each key variable affecting the problem. Solution algorithms are set up as if each variable were a known, deterministic parameter. The algorithms are exercised repeatedly, randomly selecting a different value for each variable for each iteration. In Probabilistic Fracture Mechanics, each iteration results in a failure or non-failure. Probability of failure is simply the total failures divided by the total iterations.

With Probabilistic Fracture Mechanics, cost/benefit analyses can be performed on remedial alternatives for major projects. For example, value based decisions can be made on completely re-tubing a boiler vs replacing only those components most prone to deterioration. Risk-based concepts have also been used to optimize in-service inspections performed on nuclear power plant components.

The course is designed for the end-user and is a practical seminar - not a theoretical discussion. Specific tools, such as pc-CRACK, VIPER and RRing-Life will be reviewed, as well as the general statistical analysis tool @RISK™. A reference manual will be provided each attendee.

COURSE OUTLINE

About the Instructors

Marcos Herrera, a Senior Associate at SI, received an M.S. in Engineering at the University of California, Berkeley. He has over 25 years experience in structural mechanics evaluation of nuclear power plant components. He is experienced in the application of finite element analysis, fracture mechanics, and fatigue analysis.

Darryl Rosario, an Associate at SI, received an M.S. in Mechanical Engineering at the State University of New York at Stony Brook. He has over 25 years experience in stress and fracture mechanics analyses. He is experienced in deterministic and probabilistic fracture mechanics methods, including high temperature creep-fatigue crack growth.

Pete Riccardella, Senior Technical Officer of SI, received his Ph.D. in mechanical engineering at Carnegie-Mellon University and has over 30 years of experience in the design and analysis of large structural components.  He is an authority in application of fracture mechanics to pressure vessel and piping problems.

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