This is a partial list of publications by our engineering staff. The following are on the topic of Weld Applications.
(PDF) “Weld Defects and Failures: Quantifying Fitness For Service – How Finite Element Mathematical Simulations can Mitigate Risk, Cut Costs and Improve Overall Safety”
William J. O’Donnell, Fugitive Emissions Journal, December, 2017
For chemical and petrochemical companies facing the threat of fugitive emissions, the ability to quantify a component’s fitness for service could be the difference between safety and disaster. This article shares insight about managing risk specific to weld failures.
(PDF) “Weld Defects and Failures: Quantifying Fitness For Service”
William J. O’Donnell, Stainless Steel World, December, 2017
Fatigue in welded steel components is often initiated by mechanical vibration, corrosion, and thermal cycling.
Fitness-for-service analysis is the most viable step in determining the safety and financial risk factors related
to component repair or replacement. This article shares insight about managing risk specific to weld failures.
The predictive power of finite element mathematical simulations can often prevent the loss of millions of dollars in downtime, industrial catastrophes, injuries and loss of life.
(PDF) “Solar Energy Applications: The Future (With Comparisons)” Luis Bon Rocafort and William J. O’Donnell, Chapter 5, Energy and Power Generation Handbook – Established and Emerging Technologies, K.R. Rao, Editor, 2011
“Mitigating Catastrophic Failures in Structures Used in Offshore Oil & Gas Production”January, 2011 Carl E. Spaeder, William J. O’Donnell The United States Department Of The Interior Bureau Of Ocean Energy Management Regulation And Enforcement, BOEMRE Contract No. M10PC00061
The work identified in this report includes Item 1: Implementation of a Fracture Control Plan for offshore structures; Item 2: Fatigue design criteria for offshore structures; Item 3: Fitness for Service evaluations of offshore structures; Specialized training for BOEMRE staff and inspectors
“Corrosion Fatigue: Recent Developments and Future Needs” W. J. O’Donnell
Exposure to water has recently been found to have much greater deleterious effect on the fatigue strength of the most commonly used carbon and low alloy stainless steels than previously believed. The ASME Boiler and Pressure Vessel Code and other Codes and Standards for evaluating the fatigue design life of engineered components including power plants have commonly assumed that such exposure would not reduce the fatigue life by more than a factor of that measured in air. Accordingly, a factor of two on fatigue cycles has been used to account for corrosion effects when developing the current fatigue design life curves using the data obtained in air.
“The Additional Deflection of a Cantilever Due to the Elasticity of the Support” W. J. O’Donnell, Journal of Applied Mechanics, Vol. 27, p. 461, September 1960.
A beam is cantilevered from a semi-infinite solid with neutral axis normal to its bounding plane (Two-dimensional problem). Deformation of the supporting solid allows the beam to rotate about the built-in end, producing a deflection in addition to that caused by bending and shear in the beam itself.
“An Analysis of Average Stress Intensities in Steam Generator Tube Sheet Ligaments” W. J. O’Donnell, Bettis Technical Review, No. 21, p. 79, November 1960.
An analysis of stress intensities (shear stresses) is the minimum ligament sections of steam generator tube sheets is presented. This analysis can be used to evaluate the ligament stress intensities based on stresses averaged across the minimum ligament sections and averaged through the depth of the tube sheet.
“The Effect of the Tubes on Stresses and Deflections in U-Tube Steam Generator Tube Sheets” W. J. O’Donnell, Bettis Technical Review, No. 21, p. 89, November 1960.
“Effective Elastic Constants for Steam Generator Tube Sheets” W. J. O’Donnell, Bettis Technical Review, No. 22, p. 1, March 1961.
“Analysis of Perforated Plates” W. J. O’Donnell, Doctoral Thesis, University of Pittsburgh (1962).
“Design of Perforated Plates” W. J. O’Donnell and B. F. Langer, Journal of Engineering for Industry, Transactions ASME, Vol. 84, p. 307, August 1962.
This paper describes a method for calculating stresses and deflections in perforated plates with a triangular penetration pattern. This method is based partly on theory and partly on experiment. Average ligament stresses are obtained from purely theoretical considerations but effective elastic constants and peak stresses are derived from strain measurements and photoelastic tests. Acceptable limits for pressure stresses and thermal stresses in heat exchanger tube sheets are also proposed.
“Stresses and Deflections in Built-in Beams” W. J. O’Donnell, Series B, Transactions ASME, Vol. 85, p. 265, August 1963.
(PDF) “The Fatigue Strength of Members Containing Cracks” W. J. O’Donnell &C.M. Purdy, ASME Transactions, Journal of Engineering for Industry, Vol. 86, No. 2, May 1964.
The significant loss of fatigue life due to the presence of a crack, crack-like defect, or sharp notch is predicted herein from theoretical considerations. Strength reduction factors are given as a function of the crack depth, section width and type of loading. These values are applicable where defects of a particular depth are known to exist or where defects of a limited depth could exist without being detected. Although these values apply specifically to 100,000 psi tensile strength steels, they are conservatively high for lower strength steels, aluminum, and other materials which are less sensitive to notches. The results of this paper indicate that cracks in finite width members may produce a greater loss of fatigue life than previous theoretical work for members of infinite width had indicated.
“Fatigue Design Basis for Zircaloy Component” W. J. O’Donnell, B. F. Langer, Nuclear Science &Engineering, Vol. 20, 1964
General methods have recently been developed for low cycle fatigue design. The required basic strain-controlled data for both non-irradiated and irradiated Zircaloy-2, -3, -4 were obtained for temperature between 70 F and 600 F. Data include both rolled and base-annealed material, and as-welded material tested in various directions.
“Fatigue Properties of Irradiated Pressure Vessel Steels” W. G. Gibbons, A. E. Mikoleit, and W. J. O’Donnell, ASTM publication STP-426, Effects of Irradiation on Structural Metals, November 1967.
The effects of neutron irradiation on the unnotched strain-cycled fatigue properties of pressure vessel steels were evaluated. Two heats of A302B low alloy steel and one heat of A212B carbon silicon steel were investigated. Results from room temperature tests on non-irradiated material were compared with those from irradiated material. The fatigue notch sensitivities of these materials were also investigated using V-notch specimens with two and ten mil root radii. Results were compared with theoretical predictions based on the stress theory of fatigue notch sensitivity.
“Upper Bounds for Accumulated Strains Due to Creep Ratcheting” W. J. O’Donnell and J. S. Porowski, Transactions ASME, Journal of Pressure Vessel Technology, Vol. 97, No. 3, August 1975.
A rigorous method of bounding both the total accumulated strain and the strain ranges due to cyclic operation in the creep regime is presented. These limits can be obtained from the results of purely elastic stresses analyses. The basic problem of a cylindrical vessel under internal pressure subjected to cyclic thermal stresses is solved in detail. The results are presented in graphical form suitable for design purposes.
“Theory of Free Coiled Pressure Vessels” J. S. Porowski, W. J. O’Donnell, and A.S. Roberts, presented at the ASME/CSME Pressure Vessels and Piping Conference, Montreal, Canada, June 1978. 39. “Plastic Design of Ligaments,” by W. J. O’Donnell and J. S. Porowski, ASME Pressure Vessels Piping Conference, San Francisco, California, ASME 79:PVP Vol. 37, June 1979.
“Development of Inelastic Design Criteria and Codes” W. J. O’Donnell and J. S. Porowski, invited lecture, Fifth International Conference on Structural Mechanics in Reactor Technology, Berlin, Germany, SMIRT Transactions, Vol. L 6/1, August 1979.
“Generalized Yield Surfaces for Plates and Shells” D.B. Peterson, W.C. Kroenke, W.F. Stokey, and W.J. O’Donnell, WRC Bulletin 250, July 1979
Complete expressions are derived for the lower bound loads which cause yielding of general plate and shell elements subjected to membrane, bending, and shear loads. The analyses are based on the Tresca Yield criterion and statically admissable stress distributions are used to obtain lower bound yield loads. These generalized yield surfaces are not restricted to shells of revolution subjected to axisymmetric loads. Stress limits based on these yield surface equations are proposed herein to evaluate elastically calculated primary stresses obtained using finite element or other methods. The proposed evaluation method provides a consistent and nearly uniform margin of safety against gross plastic yielding.
“A Simplified Design Procedure for Life Prediction of Rocket Thrust Chambers” J. S. Porowski, W. J. O’Donnell, M. L. Badlani, B. Kasraie, and H. J. Kasper, presented at AIAA/ASME/SAE Joint Propulsion Conference, Cleveland, Ohio, AIAA Paper 82-1251, June 21-23, 1982.
An analytical procedure for predicting thrust chamber life is developed.
(PDF) “Vessels for Elevated Temperature Service” by W. J. O’Donnell and J. S. Porowski, Chapter One, Developments in Pressure Vessel Technology:4, Book published by Applied Science Publishers Ltd., England, Edited by R. W. Nichols, 1983.
For decades, elastic analyses have been used to design steam boilers and pressure vessels. The design was considered acceptable provided that the stresses avaraged through the wall of the vessel did not exceed allowable limits. Simple formulae were given in the Codes to obtain these stresses by hand calculations. Corrective coefficients were also provided to include the effects of bending, as, for example, in the case of dished ends or plates. Since the major concern was focused on limiting average membrane stresses, the relations used to calculate stresses for comparison with the allowables were the same for elevated temperature service as for temperature service below the creep regime. The need for additional checking of the effects of bending and thermal stresses was left to the individual judgement of the designer. In most cases, the calculations were simply restricted to mechanical load effects mainly related to pressure stresses. The allowable values of stress given in the Code were intended to provide sufficient safety margins to compensate for inaccuracies and omissions of such evaluations. These design-by-formula methods used used the maximum stress criteria still in common use. It is recognized that, even for vessels where creep can be ignored, the use of such design methods should be restricted to thin wall structures where thermal stresses are of negligible importance and where the assumption of quasi-steady loading provides a good engineering approximation. The critical importance of fatigue as the limiting failure mode of most pressure vessels has only recently been fully recognized. The design-by-formula approach does not control fatigue damage since such damage is caused by local stress and strain conditions not considered in the membrane stress formula. The local maximum range of von Mises shear strain is the most important determinant of low cycle fatigue damage, with the local stress conditions contributing to a mean stress effect.
(PDF) “New Mechanical and Thermal Processes for Mitigating Stress-Corrosion and Corrosion-Accelerated Fatigue” J. S. Porowski, W. J. O’Donnell, M. L. Badlani, E. J. Hampton, and B. Kasraie, presented at ASME Pressure Vessel and Piping Conference, San Diego, California, June 24, 1991, International Journal Pressure Vessel &Piping, No. 50 (1992) pp. 63-79.
This paper describes new mechanical and thermal processes which have been developed and verified to mitigate stress-corrosion cracking and corrosion-assisted fatigue in operating plants.
“Low Cycle Thermal Fatigue and Fracture of Reinforced Piping” by W. J. O’Donnell, J. M. Watson, W. B. Mallin, and J. R. Kenrick. International Conference and Exposition on Fatigue, Corrosion Cracking, Fracture Mechanics and Failure Analysis, December 2 – 6, 1985, Salt Lake City, Utah, Proceedings published by ASM “Analyzing Failures: The Problems and the Solutions,” (ASM 8517-007).
A large diameter steel pipe reinforced by stiffening rings with saddle supports was subjected to thermal cycling as the system was started up, operated and shut down. The pipe sustained local buckling and cracking, then fractured during the first five month operation. Failure was due to low cycle fatigue and fast fracture caused by differential thermal expansion stresses. Thermal lag between the stiffening rings welded to the outside welded to the outside of the pipe and the pipe wall itself resulted in large radial and axial thermal stresses at the welds. Redundant tied down saddle supports in each segment of pipe between expansion joints restrained pipe arching due to circumferential temperature variations, producing large axial thermal bending stresses. Thermal cycling of of the system initiated fatigue cracks at the stiffener rings. When the critical crack size was reached, fast fracture ocurred. The system was redesigned by eliminating the redundant restraints which prevented axial bowing, and by modifying the stiffener rings to permit free radial thermal breathing of the pipe. Expert testimony was also provided in litigation resulting in a court decision requiring the designers of the original system to pay damages to the furnace owner.
The pipe which failed was an exhaust duct in an emission control system at a plant in Washington State. There are a pair of submerged arc electric furnaces at the site, with parallel exhaust systems running generally east/west from the furnaces to a baghouse. These furnaces burn a mixture of wood chips, bituminous coal and coke. In each system, exhaust gases are drawn from the furnace up through three stacks which converge into a single duct. The gases pass through the duct to a spark box, then through loop coolers to the baghouse. There, particulate material is removed from the gas which is then vented to the atmosphere. The evaluations, examinations, and calculations which were performed are discussed in more detail in the remainder of this paper.
“Improved Fatigue Life Evaluation Methods for LWR Components” W. J. O’Donnell, D. P. Jones, J. S. Abel, J. S. Porowski, E. J. Hampton, and M. L. Badlani, report prepared for Division of Engineering Technology, Office of Nuclear Regulatory Research, March 1987.
The applicability of a general elastic-plastic crack growth analysis method is established herein for a wide range of geometries and loading conditions including the extensive plastic cycling encountered in most fatigue testing.
“Mechanical Methods of Improving Resistance to Stress Corrosion Cracking in BWR Piping Systems” J. Abel, J. Titrington, R. Jordan, J. S. Porowski, W. J. O’Donnell, M. L. Badlani, and E. Hampton, SMIRT Post Conference, Lausanne, Switzerland, August, 1987.
“Synthesis of S-N and da/dn Life Evaluation Technologies” W. J. O’Donnell, presented at the American Society of Mechanical Engineers, Pressure Vessels and Piping Conference, Pittsburgh, Pa., PVP Vol. 10, 1988.
The S-N technology used in the ASME Code and similar criteria includes bith the crack initiation and cracl propagation phases of fatigue failure. Crack growth rate (da/dN) technology has successfully quantified various environmental (corrosion) cyclic rate, temperature, chemical composition, inclusion morphology and other effects on the crack growth rate, and (to a lesser extent) on the threshold crack growth values. The relationship between safe life evaluations based on these technologies is analyzed herein, and a general method of quantifying known crack growth rate effects in S-N curves is developed.
Fatigue stress on polished specimens are characterized by nominal stress amplitudes over yield, where linear elastic fracture mechanics (da/dN vs. dK) methods, such as those used in the ASME Code, are not valid. The small plastic zone corrections used in the Code do not account for the plastic crack driving energies encountered in low cycle fatigue testing. J integral solutions, equivalent to COD solutions, are adapted herein to evaluate the growth of of cracks in these specimens. This approach is shown to correlate the growth of cracks over the entire range of loading from elastic to grossly plastic conditions, in specimens of widely different geometries and sizes, including the growth of very short cracks for materials of major interest in pressure vessels and piping.
The analytical approach developed herein can be used to correct S-N fatigue life evaluation curves for known differences in crack growth rates whether they are due to corrosion-assisted fatigue or other variables. As an illustration, the crack growth rates given in Section XI of the ASME Code are used to include reactor water effects on A533 reactor pressure vessel steel in the fatigue design curves of Section III.
Advanced Methods of Improving Resistance to Stress Corrosion Cracking in BWR Piping Systems” J. S. Abel, J. Titrington, R. Jordan, J. S. Porowski, W. J. O’Donnell, M. L. Badlani, and E. J. Hampton, presented at the American Society of Mechanical Engineers Pressure Vessels and Piping Conference, June 19 – 23, 1988, PVP Vol. 13, 1988.
Pipelocks and the Mechanical Stess Improvement Process (MSIP) have been applied in BWR plants. Pipelocks restore the integrity of the weldments with identified cracks. MSIP removes the residual tensile stresses from weldments, thus preventing initiation of cracks or retarding growth of pre-existing flaws in piping systems. MSIP was applied for various geometries of weldments including nozzle-to-safe-end joints. Extensive verification has been completed by the United States Nuclear Regulatory Commission, EPRI and Argonne National Laboratory. Basic concepts and practical application of MSIP and Pipelocks are presented.
” (PDF) Aging and Reactor Water Effects on Fatigue Life” W. J. O’Donnell, J. S. Porowski, E. J. Hampton, M. L. Badlani, G. H. Weidenhamer, D. P. Jones, J. S. Abel, and B. Tomkins, presented at International Nuclear Power Plant Aging Symposium, Washington, D. C., August 30, 1988, Proceedings published by USNRC March 1989, NUREG/CP-0100.
Methods of including aging effects and reactor water enhanced crack propagation rates in Codified S-N fatigue life assessment curves are presented and illustrated.
“A New Role for Engineers in a Competitive World Economy” W. J. O’Donnell, Plenary Lecture, presented at the 1988 ASME Pressure Vessels and Piping Conference, Pittsburgh, Pa., June 1988.
(PDF)”Development of Fatigue Criteria for Remaining Life Assessment of Shell Structures” by J. S. Porowski, W. J. O’Donnell, M. L. Badlani, S. Chattopadhyay, and S. S. Palusamy, MPC-Vol. 29, pp. 115-123, December 1988.
A technical approach is presented for developing improved fatigue life evaluation criteria for extended life of shell structures. The objective is to develop S-N curves which include aging and environmental effects on ductility, strength, crack initiation and crack propagation properties. The use of J-integral approach is proposed for crack growth and high strain cycling along with special consideration for short cracks. The procedure also includes an approach for developing fatigue life evaluation curves for aged weldments based on crack inititation, crack growth and fracture.
“Use of Mechanical Stress Improvement Process to Mitigate Stress Corrosion Cracking in BWR Piping Systems”by J. S. Porowski, W. J. O’Donnell, M. L. Badlani, and E. J. Hampton. Nuclear Engineering and Design 124, pp. 91-100, Elsevier Science Publishers, February 1990.
“Emerging Technology for Component Life Assessment” W. J. O’Donnell and J. S. Porowski, presented at ASME Pressure Vessel and Piping Conference, San Diego, California, June 24, 1991. International Journal Pressure Vessel &Piping, No. 50 (1992) pp. 37-61.
“Use of Mechanical Stress Improvement for Weldments with Cracks” J. S. Porowski, W. J. O’Donnell, M. L. Badlani, and E. J. Hampton, Proceedings, SMIRT Post Conference Seminar No. 2, “Assuring Structural Integrity of Steel Reactor Pressure Boundary Components,” Taipei, R. O. C., August 26-28, 1991.
“Methods for Evaluating the Cyclic Life of Nuclear Components Including Reactor Water Environmental Effects” W. J. O’Donnell, J. S. Porowski, N. Irvine, B. Tomkins, D. Jones, and T. O’Donnell, Presented at ASME Pressure Vessel and Piping Conference, New Orleans, Louisiana, June 21-21, 1992, PVP Vol. 238, ASME 1992.
“Primary Stress Evaluations for Redundant Structures” W. J. O’Donnell, J. S. Porowski, B. Kasraie, G. Bielawski, and M. L. Badlani, presented at the ASME Pressure Vessel and Piping Conference, Denver, Colorado, July 25-29, 1993, ASME PVP Vol. 265, Design Analysis, Robust Methods and Stress Classification.
“Operating Nuclear Plant Feedback to ASME and French Codes” J. Journet and William J. O’Donnell, presented at the ASME Pressure Vessel and Piping Conference, Montreal, Canada, July 21-28, 1996, Pressure Vessel and Piping Codes and Standards, PVP Vol. 339-2, pp. 3-12.
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