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Search Publications by: Steven P. Mates (Fed)

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Displaying 26 - 50 of 61

Dynamic Response of Metals Subject to Rapid DC Current Pulses

June 3, 2013
Author(s)
Steven P. Mates, Graham Cullen, Eran Vax, Eli Marcus, Brad Kinsey
Recent investigations indicate that metals will deform plastically at much lower stress levels when subject to high density DC currents due to an influence of electrical current on dislocation motion that is athermal in nature. Practical applications in

Vacuum-Assisted Gas Atomization of Liquid Metal

October 17, 2012
Author(s)
Steven Mates, Stephen D. Ridder, Frank S. Biancaniello, Tony Zahrah
Vacuum-assisted gas atomization of liquid metal is explored. The investigation is motivated by observations of liquid metal atomization which indicate that secondary atomization is sustained over an extended distance from the nozzle tip. Increasing the

Transient Convection-Diffusion Modelling of Peak Temperature in Orthogonal Cutting

August 19, 2012
Author(s)
Timothy J. Burns, Steven P. Mates, Richard L. Rhorer, Eric P. Whitenton, Debasis Basak
Numerical finite-difference simulations of a two-dimensional transient fast convection-slow diffusion model of the temperature field in orthogonal cutting, due to Tlusty, have been shown to provide better predictions of the peak temperature during

Modeling the Peak Cutting Temperature During High-Speed Machining of AISI 1045 Steel

May 22, 2012
Author(s)
Timothy J. Burns, Steven P. Mates, Richard L. Rhorer, Eric P. Whitenton, Debasis Basak
This paper presents new experimental data on AISI 1045 steel from the NIST pulse-heated Kolsky Bar Laboratory. The material is shown to exhibit a stiffer response to compressive loading when it has been rapidly preheated, than it does when it has been

Modeling and DIC Measurements of Dynamic Compression Tests of a Soft Tissue Simulant

June 6, 2011
Author(s)
Steven P. Mates, Aaron M. Forster, R Rhorer, Amit Bagchi, Richard Everett, Kirth Simmonds
Stereoscopic digital image correlation (DIC) is used to measure the shape evolution of a soft, transparent thermoplastic material subject to a high strain rate compression test performed using a Kolsky bar. Rather than using the usual Kolsky bar wave

Dynamic Properties for Modeling and Simulation of Machining: Effect of Pearlite to Austenite Phase Transition on Flow Stress in AISI 1075 Steel

January 3, 2011
Author(s)
Timothy J. Burns, Steven P. Mates, Richard L. Rhorer, Eric P. Whitenton, Debasis Basak
The Pulse-Heated Kolsky Bar Laboratory at the National Institute of Standards and Technology (NIST) has been developed for the measurement of dynamic properties of metals. Because high-speed machining processes can lead to extremely rapid heating of a

Effect on Flow Stress of a Rapid Phase Transition in AISI 1045 Steel

July 13, 2010
Author(s)
Timothy J. Burns, Steven P. Mates, Richard L. Rhorer, Eric P. Whitenton, Debasis Basak
New experimental data on AISI 1045 steel from the NIST pulse-heated Kolsky Bar Laboratory are presented. The material is shown to exhibit a nonequilibrium phase transformation at high strain rate. An interesting feature of these data is that the material

Dynamic Deformation of Jacketed Lead Bullets Captured By High Speed DIC

June 7, 2010
Author(s)
Steven P. Mates
The development of high fidelity simulations of lead-cored bullet impacts on soft body armor, motivated by the need for improved armor designs and performance standards for law enforcement, requires accurate models for both the armor and the deformable

Modeling of the Temperature Field in the Chip and in the Tool in High-speed Machining of a Carbon Steel: Effect of Pearlite to Austenite Phase Transition in AISI 1075

April 7, 2010
Author(s)
Timothy J. Burns, Steven P. Mates, Richard L. Rhorer, Eric P. Whitenton, Debasis Basak, Russell H. McFadden
A one-dimensional transient finite-difference model for the temperature distribution in orthogonal metal cutting, which was originally developed by Boothroyd, and then improved upon by Tlusty, is used to calculate the temperature field in the chip and in

An electrical pulse-heated Kosky bar technique for high strain rate flow stress measurements of rapidly heated metals

September 13, 2009
Author(s)
Steven P. Mates, Stephen W. Banovic, Richard L. Rhorer, Timothy J. Burns, Eric P. Whitenton, D Basak
We have developed a unique electrical pulse-heated Kolsky Bar technique for measuring the flow stress of metals at heating rates of up to 6000 °C per second and strain rates up to 10^4 per second. Under these conditions, which are approaching those found

Machining Process Measurements: A Titanium Machining Example

June 4, 2009
Author(s)
Richard L. Rhorer, Eric P. Whitenton, Timothy J. Burns, Steven P. Mates, Jarred C. Heigel, April L. Cooke, Johannes A. Soons, Robert W. Ivester
NOTE: This is a two-page abstract for publication in the CD-ROM conference proceedings only. Oral presentation of the complete paper will be presented at the conference (SEM, June 1-4, 2009, Albuquerque). This paper discusses recent results of studying Ti

High Strain Rate Tissue Simulant Measurements Using digital Image Correlation

June 1, 2009
Author(s)
Steven P. Mates, Richard L. Rhorer, Richard Everett, Kirth Simmonds, Amit Bagchi
Measuring the response of soft materials to high strain rate deformation is extremely challenging because of the difficulty of achieving dynamic equilibrium during high strain rate mechanical testing such as Kolsky bar testing. Digital image correlation

Schlieren Imaging in Materials Processing

October 16, 2008
Author(s)
Steven P. Mates
Even before Ernst Mach used it to visualize sock waves cast by a supersonic bullet in 1888, the schlieren optical technique has been a valuable diagnostic tool in fluid mechanics, particularly int he fields of aerodynamics and heat convection, where strong

High Rate Tensile Strength Measurements of Frangible Bullets Using a Kolsky Bar

June 8, 2008
Author(s)
Steven P. Mates, Richard L. Rhorer, Stephen W. Banovic, Eric P. Whitenton, Richard J. Fields
The tensile strength of frangible bullets is measured by a high rate diametral compression test (DCT) performed with a Kolsky Bar. Frangible bullets, meant to disintegrate on impact by brittle failure, also exhibit significant plasticity in compression. As

Recent Results from the NIST Pulse-Heated Kolsky Bar

September 3, 2007
Author(s)
Timothy J. Burns, Steven Mates, Richard L. Rhorer, Eric P. Whitenton, Debasis Basak
A Kolsky bar laboratory for measuring dynamic material properties, in support of improved finite-element modeling of high-speed machining processes, has been developed at the National Institute of Standards and Technology (NIST). The NIST split-Hopkinson

Tensile Strength Measurements of Frangible Bullets Using the Diametral Compression Test

May 8, 2007
Author(s)
Steven P. Mates, Richard L. Rhorer, Stephen W. Banovic, Eric P. Whitenton, Richard J. Fields
Frangible bullets are designed to disintegrate on impact against rigid surfaces to avoid ricochet hazards in recreational shooting ranges or law enforcement training facilities. Their behavior against protective soft body armor is therefore quite different