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Search Publications by: Jeffrey T. Fong (Fed)

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Displaying 1 - 25 of 44

Role of Uncertainty in the Durability of Composite Material Systems

August 17, 2020
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben
This paper is a chapter invited by the editor of a book to be published by Elsevier in 2020. The title of the book is "Durability of Composite Systems," and the editor is Prof. Kenneth Reifsnider, N.A.E., University of Texas at Arlington, Arlington, TX, U

Design of an intelligent PYTHON code to run coupled and license-free finite-element and statistical analysis software for calibration of near-field scanning microwave microscopes

October 2, 2019
Author(s)
Jeffrey T. Fong, N. Alan Heckert, James Filliben, Pedro V. Marcal, Samuel Berweger, Thomas Mitchell (Mitch) Wallis, Pavel Kabos
To calibrate near-field scanning microwave microscopes (NSMM) for defect detection and characterization in semiconductors, it is common to develop a parametric finite element analysis (FEA) code to guide the microscope user on how to optimize the settings

DESIGN OF AN INTELLIGENT PYTHON CODE FOR VALIDATING CRACK GROWTH EXPONENT BY MONITORING A CRACK OF ZIG-ZAG SHAPE IN A CRACKED PIPE

July 27, 2019
Author(s)
Jeffrey T. Fong, Pedro V. Marcal, Robert B. Rainsberger, Nathanael A. Heckert, James J. Filliben
When a small crack is detected in a pressure vessel or piping, we can estimate the fatigue life of the vessel or piping by applying the classical law of fracture mechanics for crack growth if we are certain that the crack growth exponent is correct and the

Uncertainty Quantification of Failure Probability and a Dynamic Risk Analysis of Decision Making for Maintenance of Ageing Infrastructure

January 2, 2019
Author(s)
Jeffrey T. Fong, James J. Filliben, Nathanael A. Heckert, Dennis D. Leber, Paul A. Berkman, Robert E. Chapman
Risk, as the product of failure probability and failure consequence, has been estimated and applied by engineers and managers to help make critical decisions on (a) maintenance of ageing plants, and (b) planning of new infrastructure. For ageing plants

THREE APPROACHES TO QUANTIFICATION OF NDE UNCERTAINTY AND A DETAILED EXPOSITION OF THE EXPERT PANEL APPROACH USING THE SHEFFIELD ELICITATION FRAMEWORK

July 15, 2018
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Steven R. Doctor
The ASME Boiler & Pressure Vessel Code Section XI Committee is currently developing a new Division 2 nuclear code entitled the "Reliability and Integrity Management (RIM) program," with which one is able to arrive at a risk-informed, NDE-based engineering

UNCERTAINTY IN MULTI-SCALE CREEP RUPTURE LIFE MODELING AND A NEW APPROACH TO ESTIMATING FREQUENCY OF IN-SERVICE INSPECTION OF COMPONENTS AT ELEVATED TEMPERATURES (*)

April 3, 2018
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Marvin J. Cohn
Uncertainty in modeling the creep rupture life of a full-scale component using experimental data at microscopic (Level 1), specimen (Level 2), and full-size (Level 3) scales, is addressed by applying statistical theory of prediction intervals, and that of

MRI Birdcage RF Coil Resonance with Uncertainty and Relative Error Convergence Rates

October 4, 2017
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Pedro V. Marcal, Robert Rainsberger, Karl F. Stupic, Stephen E. Russek
In a magnetic resonance imaging (MRI) system, it is necessary to excite the nuclei of a patient into coherent precession for imaging. This requires a coupling between the nuclei and a source of radio frequency (RF) power using a transmitter. To receive a

Using Design of Experiments in Finite Element Modeling to Identify Critical Variables in Laser Powder Bed Fusion

August 11, 2016
Author(s)
Li Ma, Jeffrey T. Fong, Brandon Lane, Shawn P. Moylan, James J. Filliben, N. Alan Heckert, Lyle E. Levine
In Laser Powder Bed Fusion (L-PBF) Finite Element Analysis (FEA), input of accurate material and simulation parameters is critical for accurate predictions. It is challenging and expensive to measure and control all possible material properties and process

A STATISTICAL APPROACH TO ESTIMATING A 95 % CONFIDENCE LOWER LIMIT FOR THE DESIGN CREEP RUPTURE TIME VS. STRESS CURVE WHEN THE STRESS ESTIMATE HAS AN ERROR UP TO 2 % (*)

July 17, 2016
Author(s)
Jeffrey T. Fong, James J. Filliben, Nathanael A. Heckert, Pedro V. Marcal, Marvin J. Cohn
Recent experimental results on creep-fracture damage with minimum time to failure (minTTF) varying as the 9th power of stress, and a theoretical consequence that the coefficient of variation (CV) of minTTF is necessarily 9 times that of the CV of the

Uncertainty Quantification of Stresses in a Cracked Pipe Elbow Weldment Using a Logistic Function Fit, a Nonlinear Least Squares Algorithm, and a Super-Parametric Method

December 30, 2015
Author(s)
Jeffrey T. Fong, James J. Filliben, Nathanael A. Heckert, Pedro V. Marcal, Robert Rainsberger, Li Ma
In a 3-part series of papers, of which this paper is Part II, we investigate the applicability of the fully quadratic hexa-27 element (see Part I) to four problems of interest to the pressure vessels and piping community: (1) The solid-element-based

A Design-of-Experiments Approach to FEM Uncertainty Analysis for Optimizing Magnetic Resonance Imaging RF Coil Design

October 10, 2014
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Li Ma, Karl F. Stupic, Kathryn E. Keenan, Stephen E. Russek
Using the RF module of COMSOL, we compute the magnetic flux density norm (BN) profiles for frequencies in the 76 to 100 MHz range, inside of a prototype birdcage coil, courtesy of Japan's National Institute of Radiological Sciences (NIRS), loaded with a

Determining Mechanical Reliability of Brittle Materials

April 18, 2013
Author(s)
Stephen W. Freiman, Jeffrey Fong
The widespread existence of slow crack growth in most glasses and ceramics due to a stress-enhanced reaction between an external environment and strained bonds at a crack tip greatly complicates the challenge of assuring the reliability of components which

A Stochastic and Local Theory of Fatigue for Aging Pressure Vessels and Piping

November 4, 2012
Author(s)
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben
We begin with a review of the fatigue design methodology for new pressure vessels and piping, based on both deterministic and stochastic approaches. We will then prove that the same methodology for estimating the remaining life of aging pressure vessels

A Risk-Uncertainty Formula Accounting for Uncertainties of Failure Probability and Consequence in a Nuclear Powerplant

July 20, 2010
Author(s)
Jeffrey T. Fong, Stephen R. Gosselin, Pedro V. Marcal, James J. Filliben, Nathanael A. Heckert, Robert E. Chapman
This paper is a continuation of a recent ASME Conference paper entitled "Design of a Python-Based Plug-in for Bench-marking Probabilistic Fracture Mechanics Computer Codes with Failure Event Data" (PVP2009-77974). In that paper, which was co-authored by