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Search Publications by: Andrew Slifka (Fed)

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Displaying 26 - 50 of 150

HEXRD Measurement of Strain and Dislocation Density ahead of Crack Tips Grown in Hydrogen

September 13, 2019
Author(s)
Matthew J. Connolly, May L. Martin, Peter E. Bradley, Damian S. Lauria, Andrew J. Slifka, Jun Sang Park, Robert Amaro
The deformation fields near fatigue crack tips grown in hydrogen and in air were measured using high-energy x-ray diffraction. A larger magnitude of elastic strain was observed in the hydrogen case compared to the air case. The magnitude of elastic strain

Fatigue Testing of Pipeline Welds and Heat-Affected Zones in Pressurized Hydrogen Gas

April 26, 2019
Author(s)
Elizabeth S. Drexler, Andrew J. Slifka, Robert L. Amaro, Jeffrey W. Sowards, Matthew J. Connolly, May L. Martin, Damian S. Lauria
Several welds and associated heat-affected zones (HAZs) on two API X70 and two API X52 pipes were tested to determine the fatigue crack growth rate (FCGR) in pressurized hydrogen gas and assess the area of the pipe that was most susceptible to fatigue when

Hydrogen Isotope Effect in Embrittlement and Fatigue Crack Growth of Steel

March 7, 2019
Author(s)
Matthew J. Connolly, Andrew J. Slifka, Robert L. Amaro, Elizabeth S. Drexler, May L. Martin
The corrosive effect of hydrogen on steel is a long-standing problem. Corrosion in the presence of hydrogen is, in part, a consequence of the fast diffusion of hydrogen in ferritic steels. Because of the identical chemical properties but large differences

Demonstration of a Chamber for Strain Mapping of Steel Specimens Under Mechanical Load in a Hydrogen Environment by Synchrotron Radiation

June 4, 2018
Author(s)
Matthew J. Connolly, Peter E. Bradley, Damian S. Lauria, Andrew J. Slifka, Elizabeth S. Drexler
We present a demonstration of a chamber for diffraction measurements of lattice strain for specimens in hydrogen gas under mechanical load. The chamber is suitable for static and cyclic mechanical loading. Synchrotron x-ray radiographs of a fatigue crack

In Situ Neutron Transmission Bragg Edge and Synchrotron X-Ray Measurement of Strain Fields Near Fatigue Cracks Grown in Hydrogen

April 18, 2018
Author(s)
Matthew J. Connolly, Peter E. Bradley, Damian S. Lauria, Andrew J. Slifka, Elizabeth S. Drexler
The embrittlement and enhanced fatigue crack growth rate of metals in the presence of hydrogen is a long-standing problem. In an effort to determine the dominate damage mechanism behind hydrogen assisted fatigue crack growth, we performed High-Energy X-ray

Fatigue measurement of pipeline steels for application of gaseous hydrogen transport

February 5, 2018
Author(s)
Andrew J. Slifka, Elizabeth S. Drexler, Robert L. Amaro, Louis E. Hayden, Damian S. Lauria, Nikolas W. Hrabe, Douglas G. Stalheim
A comprehensive testing program to determine the fatigue crack growth rate of pipeline steels in pressurized hydrogen gas was completed; the project was sponsored by the Department of Transportation, and was conducted in close collaboration with the ASME

FATIGUE CRACK GROWTH RATES OF API X70 PIPELINE STEELS IN PRESSURIZED HYDROGEN GAS COMPARED WITH AN X52 PIPELINE IN HYDROGEN SERVICE

September 1, 2017
Author(s)
Elizabeth S. Drexler, Andrew J. Slifka, Robert L. Amaro, Damian S. Lauria, Jeffrey W. Sowards
At the present time, steel selection for hydrogen pipelines is limited to API X52 grade. However, the code is being modified to include higher strength steels, such as X70. Fatigue crack growth (FCG) tests were conducted at NIST (Boulder) on an X52

APPLICATION OF A MODEL OF HYDROGEN-ASSISTED FATIGUE CRACK GROWTH IN 4130 STEEL

July 31, 2017
Author(s)
Andrew Slifka, Robert L. Amaro, Devin T. O'Connor, Benjamin E. Long, Elizabeth S. Drexler
In this work, we applied a finite element model to predict the cyclic lifetime of 4130 steel cylinders under the influence of hydrogen. This example is used to demonstrate the efficacy of a fatigue crack growth (FCG) model we have developed. The model was

COMPUTATIONAL MODELING OF HYDROGEN-ASSISTED FATIGUE CRACK GROWTH IN PIPELINE STEELS

July 31, 2017
Author(s)
Andrew Slifka, Robert L. Amaro, Elizabeth S. Drexler, Devin T. O'Connor, Benjamin E. Long
In this work we further develop a model to predict hydrogen-assisted fatigue crack growth in steel pipelines and pressure vessels. This implementation of the model is informed by finite element code, which uses an elastic-plastic constitutive model in