Session: 12-02: Structural Health Monitoring II

Paper Number: 135261

135261 - A Multi-Scale Minimum Time-to-Failure Reliability Model for Estimating Reliability Lower Bound of a Structural Health Monitored Cracked 316L(N) Stainless Steel Component in Creep at Elevated Temperatures 

Abstract: 

The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) Committee has recently developed a new Section XI (Nuclear Components Inspection) Division 2 Code named "Reliability and Integrity Management (RIM)."  RIM incorporates a new concept known as "System-Based Code (SBC)" originally due to Asada and his colleagues (2001-2004), where an integrated approach from design to service inspection is introduced using three new types of statistical quantities: (1) "system reliability index," or "system reliability target" for any system consisting of structures and components, (2) "structural reliability," for any structure, and (3) "component reliability" for any component.   In a recent paper published in the International Journal of Pressure Vessels and Piping (Vol. 173 (2019), pp. 79-93), Fong, Heckert, Filliben, and Freiman developed a new theory of fatigue and creep rupture life modeling for metal alloys and brittle materials at room and elevated temperatures such that the reliability lower bound of a smooth component can be estimated from fatigue and creep rupture test data with simple loading histories.  In this paper, we extend the theory to include a methodology to estimate the failure probability upper bound (or, reliability lower bound) of a structural health monitored cracked stainless steel 316L(N) component undergoing a loading history of creep, creep crack initiation, and creep crack growth at elevated temperatures such as 650 ^oC. To illustrate an application of this new modeling approach, we present a numerical example using (a) the experimental test data of of S.S. 316L(N) in creep at 650 ^oC as published by Kilian Wasmer in his Ph.D. thesis (Imperial College London, 2003), and (b) the experimental test data of S.S. 316L(N) in creep crack initiation and growth at 650 ^oC also by Wasmer (Ph.D. thesis, 2003), (1993)).  The significance and limitations of this new damage-state-based approach to modeling creep crack growth and estimating the reliability lower bound of a QNDE or structural health monitored cracked component in creep at elevated temperatures, are discussed.

Presenting Author: Jeffrey Fong National Inst. of Standards & Tech.

Presenting Author Biography: Dr. Fong was educated at the University of Hong Kong (B.Sc.), Columbia University (M.S.), and Stanford University (Ph.D., Applied Mechanics and Mathematics).
He began his career as a civil engineer working for 8 years at an engineering consulting firm in New York City. After graduating from Stanford, he joined the United States National Institute of Standards and Technology (NIST), then known as the National Bureau of Standards, and has been there ever since as Physicist and Project manager in its Applied and Computational Mathematics Division.
During his 50+ years of service at NIST. Dr. Fong conducted research in applied mathematics and statistical engineering, and has provided consulting services to government, industry, and academia in engineering and materials science failure analysis, and engineering structural safety inspection, reliability, and uncertainty quantification.
He has published more than 150 papers and edited or co-edited 17 conference proceedings on fatigue, fracture, creep, nondestructive examination, engineering reliability, and uncertainty quantification in computational modeling. A book-chapter entitled "The Role of Uncertainty in the Durability of Composite Material Systems," co-authored by him, Alan Heckert, and James Filliben, all of NIST, will soon appear in a book by Elsevier entitled "Durability of Composite Systems".

Authors:

Jeffrey T. Fong National Inst. of Standards & Tech.