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Displaying 26 - 50 of 66

Dynamic Apparatus for the CTOA Measurement in Pipeline Steels

August 1, 2008
Author(s)
Avigdor Shtechman, Christopher N. McCowan, Roni Reuven, Elizabeth S. Drexler, Philippe P. Darcis, John M. Treinen, R. Smith, J. Merritt, Thomas A. Siewert, Joseph D. McColskey
When a crack initiates and propagates in a pressurized pipe the only thing that might stop this high-velocity event is the release of internal pressure (decompression) resulting in a deceleration in the crack-propagation rate. This deceleration can be

Stiffening of the Extrapulmonary Arteries in Chronic Hypoxic Pulmonary Hypertension

July 1, 2008
Author(s)
Elizabeth S. Drexler, J. E. Bischoff, Christopher N. McCowan, Andrew Slifka, Timothy P. Quinn, R Shandas, Dunbar Ivy, K. R. Stenmark
It is increasingly appreciated that changes in the compliance properties of large blood vessels are critical determinants of ventricular afterload and ultimately dysfunction. Little is known of the mechanical properties of large vessels in the setting of

Peer review report: Pipeline and hazardous materials safety administration, pipeline safety research and development program

May 14, 2008
Author(s)
Richard J. Fields, Louis E. Hayden, Thomas J. O'Grady, Joseph D. McColskey, Joe C. Bowles, T. R. Webb, Christopher N. McCowan, Dennis W. Hinnah, Ronald W. Haupt, Thomas A. Siewert
The purpose of this document is to report findings from the research peer reviews held March 27-29, 2007 for PHMSA's Pipeline Safety Research and Development Program. The findings and recommendations in this report derive from the scoring and comments

Dynamic Force Measurement: Instrumented Charpy Impact Testing

January 1, 2008
Author(s)
Christopher N. McCowan, Jolene Splett, E. Lucon
The maximum forces measured by the machines in this round robin are in good agreement. This general result shows that the static force calibration of instrumented strikers is quite robust, and that the various striker designs evaluated here performed in a

The role of metallurgy in the NIST investigation of the world trade center towers collapse

November 1, 2007
Author(s)
Stephen W. Banovic, Timothy J. Foecke, William E. Luecke, Joseph D. McColskey, Christopher N. McCowan, Thomas A. Siewert, Frank W. Gayle
On August 21, 2002, on the direction of the U.S. Congress, the National Institute of Standards and Technology (NIST) initiated an investigation into the collapse of the World Trade Center (WTC) towers. In support of the overall investigation goals, the

Crack Tip Opening Angle Optical Measurement Methods in Five Pipeline Steels

October 16, 2007
Author(s)
Philippe P. Darcis, Christopher N. McCowan, H. Windhoff, Joseph D. McColskey, Thomas A. Siewert
Crack tip opening angle (CTOA) is becoming one of the more widely accepted properties for characterizing fully plastic fracture. In fact, it has been recognized as a measure of the resistance of a material to fracture in cases where there is a large degree

Measurement of Weld Toughness - Crack Tip Opening Angle Criterion

June 1, 2007
Author(s)
Philippe P. Darcis, Joseph D. McColskey, Christopher N. McCowan, Thomas A. Siewert
The stable tearing behavior of X100 pipeline steel through a girth weld section was investigated using a modified double cantilever beam specimens. A test technique for direct measurement of the steady state crack tip opening angle (CTOA) criterion was

Fracture Toughness through a Welded Pipeline Section - Crack Tip Opening Angle Criterion

April 23, 2007
Author(s)
Philippe P. Darcis, Christopher N. McCowan, Elizabeth S. Drexler, Joseph D. McColskey, Avigdor Shtechman, Thomas A. Siewert
The increasing demand for natural gas as an alternative energy source implies continued growth of gas pipeline installations. This trend compels the natural gas transmission industry to consider the construction of larger-diameter, higher-pressure

Stress-strain behavior of rat pulmonary arteries

January 1, 2007
Author(s)
Elizabeth S. Drexler, J Wright, Andrew Slifka, Christopher N. McCowan, Dunbar Ivy, R Shandas
The stress-strain behavior of rat pulmonary arteries was studied using a bubble inflation technique. To obtain mechanical properties, an analytical method to evaluate the bubble test results was developed. A flat disk of rat pulmonary artery was

Crack Tip Opening Angle: Measurement and Modeling of Fracture Resistance in Low and High Strength Pipeline Steels

September 1, 2006
Author(s)
Philippe P. Darcis, Joseph D. McColskey, Christopher N. McCowan, Thomas A. Siewert, Gabriel Kohn, Arry Bussiba, Richard J. Fields
Crack tip opening angle (CTOA) is becoming one of the more widely accepted properties for characterizing fully plastic fracture. In fact, it has been recognized as a measure of the resistance of a material to fracture, in cases where there is a large

Fatigue Crack Growth Rates in Five Pipeline Steels

September 1, 2006
Author(s)
Arry Bussiba, Philippe P. Darcis, J D. McCloskey, Christopher N. McCowan, Thomas A. Siewert, Gabriel Kohn, R P. Smith, J. Merritt
This study presents fatigue data for six different pipeline steels, with strengths ranging from Grade B to X100. A fatigue crack growth test for full-thickness pipeline samples was developed using a Middle Tension (MT) type specimen. The six steels showed

Second Symposium on Pendulum Impact Machines: Procedures and Specimens

August 1, 2006
Author(s)
Thomas A. Siewert, Christopher N. McCowan, M. P. Manahan
This publication consists primarily of the papers presented at the Second Symposium on Pendulum Impact Machines: Procedures and Specimens, sponsored by ASTM Committee E28 on Mechanical Testing and its Subcommittee E28.07 on Impact Testing. The Symposium

International Comparison of Impact Reference Materials (2004)

April 3, 2006
Author(s)
Christopher N. McCowan, G. Roebben, Y. Yamaguchi, S. Lefrancois, Jolene D. Splett, S. Takagi, A. Lamberty
A three-year horizontal comparison has been completed between national laboratories that certify specimens for the indirect verification of Charpy impact test machines. The participants in this study were the Institute for Reference Materials and

Analysis of Charpy impact verification data: 1993-2003

March 1, 2006
Author(s)
Jolene D. Splett, Christopher N. McCowan
Indirect verification tests, used to verify the performance of Charpy impact machines according to ASTM Standard E23, are evaluated by the National Institute of Standards and Technology (NIST) and the data from these tests are co1lected in a database. The

The development of procedures for impact testing

February 1, 2006
Author(s)
Thomas A. Siewert, Christopher N. McCowan
This report provides a broad overview of the progress in procedural improvements for impact testing. It includes a short summary of early developments, a discussion of topics that have been the subject of recent research, and a description of the

Mechanical and Metallurgical Analysis of Structural Steel. Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-3) ***DRAFT for Public Comments***

September 1, 2005
Author(s)
Frank W. Gayle, Richard J. Fields, William E. Luecke, Stephen W. Banovic, Timothy J. Foecke, Christopher N. McCowan, Joseph D. McColskey, Thomas A. Siewert
This report is an overview of the results of the mechanical and metallurgical analysis of structural steel from the World Trade Center (WTC), part of the National institute of Standards and Technology Investigation of the WTC disaster of September 11, 2001

Mechanical Properties of Structural Steels. Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-3D) ***DRAFT for Public Comments***

September 1, 2005
Author(s)
William E. Luecke, Joseph D. McColskey, Christopher N. McCowan, Stephen W. Banovic, Richard J. Fields, Timothy J. Foecke, Thomas A. Siewert, Frank W. Gayle
This report provides five types of mechanical properties for steels from the World Trade Center (WTC): elastic, room-temperature tensile, room-temperature high strain rate, impact, and elevated-temperature tensile. Specimens of 29 different steels

Physical Properties of Structural Steels. Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-3E) ***DRAFT for Public Comments***

September 1, 2005
Author(s)
Stephen W. Banovic, Christopher N. McCowan, William E. Luecke
This report describes the physical properties of the structural steel recovered from the World Trade Center (WTC) towers. Analytical techniques were used to determine and evaluate the chemistry, microstructure, and thermal properties of the steels. While

Implementation and Application of a Microstructurally Based Orthotropic Hyperelastic Model of Pulmonary Artery Mechanics under Normotensive and Hypertensive Conditions

August 1, 2005
Author(s)
Yang Zhang, Martin Dunn, Elizabeth S. Drexler, Christopher N. McCowan, Andrew Slifka, Dunbar Ivy, R Shandas
We implemented, validated, and applied a microstructurally based orthotropic hyperelastic constitutive model to simulate pulmonary artery mechanics under normotensive and hypoxic hypertensive conditions. The configuration of the model microstructure is a

FORENSIC STUDY OF THE STEEL IN THE WORLD TRADE CENTER

December 30, 2004
Author(s)
Thomas A. Siewert, Joseph D. McColskey, Christopher N. McCowan, Frank W. Gayle, William E. Luecke, Stephen W. Banovic, Timothy J. Foecke, Richard J. Fields
In September of 2002, the National Institute of Standards and Technology began a two-year investigation into the World Trade Center (WTC) disaster of September 11, 2001. Now almost complete, the investigation addresses many aspects of the catastrophe, from