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Dive into the research topics where Frederick W. Brust is active.

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Featured researches published by Frederick W. Brust.


Journal of Pressure Vessel Technology-transactions of The Asme | 2000

Welding Residual Stresses and Effects on Fracture in Pressure Vessel and Piping Components: A Millennium Review and Beyond

Pingsha Dong; Frederick W. Brust

In this paper, the recent advances in weld residual stress modeling procedures are first reviewed within the context of pressure vessel and piping applications. A typical pipe girth weld was then used as an example to highlight some of the critical issues in weld residual stress prediction, measurement, and residual stress effects on various aspects of fracture behaviors from stress intensity factor solutions for a growing crack to crack-opening displacement calculations for leak-before-break assessment. Finally, the future needs in improved fracture mechanics procedures by incorporating the rapidly expanding knowledge on weld residual stresses are summarized with respect to pressure vessel and piping applications.


International Journal of Pressure Vessels and Piping | 1998

Crack-opening-area analyses for circumferential through-wall cracks in pipes—Part I: analytical models

S. Rahman; Frederick W. Brust; Nu Ghadiali; Gery Wilkowski

Abstract Leak-before-break (LBB) analyses for circumferentially cracked pipes are currently being conducted in the nuclear industry to justify elimination of pipe whip restraints and jet impingement shields which are present because of the expected dynamic effects from pipe rupture. The application of the LBB methodology requires calculation of leak rates. The leak rates depend on the crack-opening area of the through-wall crack in the pipe. In addition to LBB analyses which assume a hypothetical flaw size, there is also interest in the integrity of actual leaking cracks corresponding to current leakage detection requirements in NRC Regulatory Guide 1.45, or for assessing temporary repair of Class 2 and 3 pipes that have leaks, as are being evaluated in ASME Section XI. The objectives of this study were to review, evaluate, and refine current predictive models for performing crack-opening-area analyses of circumferentially cracked pipes. A three-phase effort was undertaken to accomplish this goal. It is described here in a series of three papers generated from this study. In this first paper (Part I — Analytical models), a comprehensive review is performed to determine the current state-of-the-art in predicting crack-opening displacements for circumferentially cracked pipes under pure bending, pure tension, and combined bending and tension loads. Henceforth, new and improved analytical models and some preliminary results are presented for cases where current methods are inadequate or there are no available methods. Also, based on this review, a number of appropriate predictive models are identified for a systematic evaluation of their accuracy. The results of their evaluations will be presented and examined in the forthcoming companion papers (Part II — Model validations [1] and Part III — Off-center cracks, restraint of bending, thickness transition, and weld residual stresses) [2] .


International Journal of Pressure Vessels and Piping | 1998

Crack-opening-area analyses for circumferential through-wall cracks in pipes—Part II: model validations

S. Rahman; Frederick W. Brust; Nu Ghadiali; Gery Wilkowski

Abstract This is the second paper in a series of three papers generated from a recent study on crack-opening-area analysis of circumferentially cracked pipes for leak-before-break applications. This paper (Part II—Model Validations) focuses on the evaluation of current analytical models, discussed in the first paper (Part I—Analytical Models) as well as finite element models for conducting crack-opening-area analyses of pipes with circumferential through-wall cracks. The evaluation was performed by direct comparisons of the predicted results with the test data from full-scale pipe fracture experiments. The results from 25 full-scale pipe fracture experiments, conducted in the Degraded Piping Program, the International Piping Integrity Research Group Program and the Short Cracks in Piping and Piping Welds Program, were used to verify the analytical models. The main objective was the evaluation of engineering analysis procedures (estimation methods) as well as the ability of the finite element method to predict crack-opening displacements and shapes in pipes with circumferential through-wall cracks. Statistics were developed to quantify the accuracy of the current predictive models. A wide variety of pipe fracture tests involving cracks in base metals, weld metals and bimetallic weld metals were analyzed. Pipes containing both simple through-wall cracks and complex cracks were evaluated.


Nuclear Engineering and Design | 1991

Approximate fracture methods for pipes — part I: theory

P. Gilles; Frederick W. Brust

Abstract Five simplified methods for predicting the fracture performance of circumferentially through-wall cracked pipes under pure bending are presented and discussed here, in this first-part paper. The theoretical foundations of the methods are examined in detail. In the second part paper, moment—rotation predictions of cracked pipes experiencing stable crack growth are compared to experimental results and their capabilities checked with three-dimensional elasto—plastic finite element computations. In spite of their simplified theoretical foundations, these schemes give quite good predictions and are very easy to use.


Nuclear Engineering and Design | 2000

Modeling of weld residual stresses in core shroud structures

Jinmiao Zhang; Pingsha Dong; Frederick W. Brust; William J. Shack; Michael E Mayfield; Michael McNeil

This paper presents a computational model to predict residual stresses in a girth weld (H4) of a BWR core shroud. The H4 weld is a multi-pass submerged-arc weld that joins two type 304 austenitic stainless steel cylinders. An axisymmetric solid element model was used to characterize the detailed evolution of residual stresses in the H4 weld. In the analysis, a series of advanced weld modeling techniques were used to address some specific welding-related issues, such as material melting/re-melting and history annihilation. In addition, a 3-D shell element analysis was performed to quantify specimen removal effects on residual stress measurements based on a sub-structural specimen from a core shroud. The predicted residual stresses in the H4 weld were used as the crack driving force for the subsequent analysis of stress corrosion cracking in the H4 weld. The crack growth behavior was investigated using an advanced finite element alternating method (FEAM). Stress intensity factors were calculated for both axisymmetric circumferential (360°) and circumferential surface cracks. The analysis results obtained from these studies shed light on the residual stress characteristics in core shroud weldments and the effects of residual stresses on stress corrosion cracking behavior.


Nuclear Engineering and Design | 1987

Degraded piping program-phase II progress

Gery Wilkowski; J. Ahmad; D. Barnes; Frederick W. Brust; N. Ghadiali; D. Guerrieri; J.F. Kiefner; G. Kramer; M. Landow; C.W. Marschall; W. Maxey; M. Nakagaki; V. Papaspyropoulos; V. Pasupathi; P. Scott

Abstract This paper summarizes the results from the NRC Degraded Piping Program over the last year. The objective of the NRC Degraded Piping Program - Phase II, is to verify limit-load analyses and develop elastic-plastic fracture mechanics analyses methods for cracked (degraded) nuclear piping under a variety of loading conditions. These analyses are used in leak-before-break evaluations. Since experimental efforts are conducted at LWR temperatures, failure modes and metallurgical phenomena of concern are also being assessed.


ASME 2007 Pressure Vessels and Piping Conference | 2007

Weld Residual Stresses and Primary Water Stress Corrosion Cracking in Bimetal Nuclear Pipe Welds

Frederick W. Brust; P. Scott

There have been incidents recently where cracking has been observed in the bi-metallic welds that join the hot leg to the reactor pressure vessel nozzle. The hot leg pipes are typically large diameter, thick wall pipes. Typically, an inconel weld metal is used to join the ferritic pressure vessel steel to the stainless steel pipe. The cracking, mainly confined to the inconel weld metal, is caused by corrosion mechanisms. Tensile weld residual stresses, in addition to service loads, contribute to PWSCC (Primary Water Stress Corrosion Cracking) crack growth. In addition to the large diameter hot leg pipe, cracking in other piping components of different sizes has been observed. For instance, surge lines and spray line cracking has been observed that has been attributed to this degradation mechanism. Here we present some models which are used to predict the PWSCC behavior in nuclear piping. This includes weld model solutions of bimetal pipe welds along with an example calculation of PWSCC crack growth in a hot leg. Risk based considerations are also discussed.Copyright


International Journal of Fracture | 1997

Approximate methods for predicting J-integral of a circumferentially surface-cracked pipe subject to bending

S. Rahman; Frederick W. Brust

This study proposes two new methods to estimate the energy release rate of a circumferentially cracked pipe with an internal, constant-depth, finite-length surface flaw subjected to pure bending loads. The methods are based on the deformation theory of plasticity, constitutive law characterized by Ramberg-Osgood model, and an equivalence criterion incorporating reduced thickness analogy for simulating system compliance due to the presence of a crack. Closed-form solutions were developed in terms of elementary functions for an approximate evaluation of J-integral. They are general and can be applied in the complete range between elastic and fully plastic conditions. Several numerical examples are presented to illustrate the proposed methods. The comparisons with the results of elastic-plastic finite element analysis showed satisfactory prediction of J-integral by one of the proposed methods.


Nuclear Engineering and Design | 1991

Approximate fracture methods for pipes — Part II: Applications

P. Gilles; K.S. Chao; Frederick W. Brust

Abstract In the part I paper entitled “Approximate fracture methods for pipes — Part I, Theory” [4], five different J- estimation schemes for through-wall cracked pipes were presented. The (i) GE.EPRI method utilizes a compilation of finite-element solutions. The (ii) Paris/Tada and (iii) LBB.NRC methods utilize an interpolation between the linear elastic and rigid plastic solutions, (iv) the LBB.GE method also uses numerical solutions, and (v) the LBB.ENG uses an equivalent area method to estimate J . All five methods are very simple to use and all five give reasonable predictions of crack growth and failure in pipes. The present paper provides a comparison of some of the methods to full-scale finite-element analyses. In addition, predictions for actual pipe experiments compared to experimental data are also provided.


Journal of Pressure Vessel Technology-transactions of The Asme | 1992

Elastic-Plastic Fracture of Circumferential Through-Wall Cracked Pipe Welds Subject to Bending

S. Rahman; Frederick W. Brust

A methodology is proposed to carry out elastic-plastic fracture analysis of through-wall cracked ductile pipe weldments subjected to pure bending loads. It is based on deformation theory of plasticity, constitutive law characterized by Ramberg-Osgood model, and an equivalence criteria incorporating reduced thickness analogy for simulating system compliance due to the presence of a crack in weld metal. Closed-form solutions are obtained in terms of elementary functions for approximate evaluation of energy release rate and center crack opening displacement. The method utilizes material properties of both base and weld metals which are not considered in the current estimation methods. It is general and can be applied in the complete range between elastic and fully plastic conditions. Numerical examples are presented to illustrate the proposed technique. Comparisons of results with reference solutions from finite element method indicate satisfactory prediction of foregoing fracture parameters.

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Gery Wilkowski

Battelle Memorial Institute

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P. Scott

Battelle Memorial Institute

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Pingsha Dong

Battelle Memorial Institute

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David L. Rudland

Battelle Memorial Institute

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P. Dong

Battelle Memorial Institute

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D. Rudland

Nuclear Regulatory Commission

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