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Search Publications by: Thomas H. Gnaupel-Herold (Fed)

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Displaying 1 - 25 of 49

Elastic Behavior of Orientation-Correlated Grains in Multiphase Aggregates

October 1, 2023
Author(s)
Thomas Gnaupel-Herold
Diffraction elastic constants (DECs) describe the elastic response of a subset of orientation-correlated grains which share a common lattice vector. DECs reflect the elastic behaviour of the single-crystal constituents through their dependence on grain

Influence of Drawbeads in Deep Drawing of Plane-Strain Channel Sections

October 12, 2021
Author(s)
D E. Green, T B. Stoughton, Thomas H. Gnaupel-Herold, Mark Iadicola, Timothy J. Foecke
The Numisheet 2005 Benchmark 3 consisted of forming four different automotive sheet materials in a two-stage process. The first stage consisted of forming channel sections in an industrial-scale channel draw die in which material flow is controlled by

Two Stage Forming: Experimental and FE Analysis

October 12, 2021
Author(s)
M C. Oliveira, A J. Baptista, J L. Alves, L F. Menezes, D E. Green, Thomas H. Gnaupel-Herold, Mark Iadicola, Timothy J. Foecke, T B. Stoughton
One of the present challenges in sheet metal forming is to simulate sequential production stages, from the initial blank sheet to the final part ready for assembly. In this context, it is fundamental to evaluate the forming characteristics of the materials

Micromechanical Behaviorof Multilayered Ti/Nb Composites Processed by Accumulative Roll Bonding: An in-situ Synchrotron X-ray Diffraction Investigation

February 14, 2021
Author(s)
S. Jiang, R. L. Peng, Z. Hegedus, Thomas Gnaupel-Herold, J. J. Moverare, U. Lienert, F. Fang, X. Zhao, L. Zuo, N. Jia
Ti/Nb multilayered composites were fabricated by accumulative roll bonding (ARB). With increasing ARB cycles, shear bands become predominant in the continuously strengthened composites. The correlation between micromechanical behavior and mechanical

Elastic residual strain and stress measurements and corresponding part deflections of 3D AM builds of IN625 AM-Bench artifacts using neutron diffraction, synchrotron X-ray diffraction, and contour method

July 29, 2019
Author(s)
Thien Q. Phan, Maria Strantza, Michael R. Hill, Thomas H. Gnaupel-Herold, Jarred C. Heigel, Christopher D'Elia, DeWald Adrian, Bjorn Clausen, Darren C. Pagan, J. Y. Peter Ko, Donald W. Brown, Lyle E. Levine
One of the primary barriers for acceptance of additive manufacturing (AM) has been the uncertainty in the performance of AM parts due to residual stresses/strains. The rapid heating and cooling rates, along with the thermal history of the laser melting

Fracture Mechanics Approach to Splitting in Low Spring Index Cold Coiling Process

June 1, 2019
Author(s)
Y. Prawoto, S. Manville, T. Sakai, L. Lee, M. Tanaka, Thomas H. Gnaupel-Herold
This paper is an attempt to understand the coil splitting phenomena by means of fracture mechanics. The methods used combines the residual stress measurement with neutron and finite element analysis. The support of the metallurgical evaluation is used as

Residual Stress in Additive Manufactured Nickel Alloy 625 Parts

June 29, 2018
Author(s)
Lindsey B. Bass, Justin L Milner, Thomas H. Gnaupel-Herold, Shawn P. Moylan
One of the key barriers to widespread adoption of additive manufacturing (AM) for metal parts is the build-up of residual stresses. In the laser-based powder bed fusion process, a laser selectively fuses metal powder layer by layer, generating significant

Design of an Octo-Strain Specimen for Biaxial Tension Testing

June 18, 2018
Author(s)
Justin L Milner, Thomas H. Gnaupel-Herold
A custom biaxial testing fixture was designed to evaluate a new specimen geometry for complex loading paths. Biaxial testing is commonly used to evaluate work-hardening behavior of sheet metal in biaxial tension to study the accumulation of plastic strains

Stress Profiling in Cold-Spray Coatings by Different Experimental Techniques: Neutron Diffraction, X-ray Diffraction and Slitting Method

April 1, 2018
Author(s)
Vladimir Luzin, Kevin Spencer, Michael R. Hill, Tao Wei, Michael Law, Thomas H. Gnaupel-Herold
The residual stress profiles in Cu and Al coatings sprayed using kinetic metallization to thickness of 2 mm have been studied. Due to specific parameters of the cold spray process and particular combination of materials of coatings and substrates the

Increased interference fringe visibility from the post fabrication heat treatment of a perfect crystal silicon neutron interferometer

February 8, 2018
Author(s)
Michael G. Huber, Muhammad D. Arif, Thomas H. Gnaupel-Herold, Michelle E. Jamer, Ben Heacock, David G. Cory, R. Haun, Joachim Nsofini, Dimitry A. Pushin, Ivar Taminiau, A.R. Young
We find that annealing a previously chemically etched interferometer at 800 °C dramatically increased the interference fringe visibility from 23 % to 90 %. The Bragg plane misalignments were also measured before and after annealing using neutron rocking

Formation of the Ni3Nb delta-phase in stress-relieved Inconel 625 produced via powder-bed laser fusion additive manufacturing

August 23, 2017
Author(s)
Eric Lass, Mark R. Stoudt, Maureen E. Williams, Michael B. Katz, Thien Q. Phan, Lyle E. Levine, Thomas H. Gnaeupel-Herold
The microstructural evolution of laser powder-bed additively manufactured Inconel 625 during a post-build stress-relief anneal of 1 h at 870 °C is investigated. It is found that this industry-recommended heat treatment promotes the formation of a

Anisotropy, Tension-Compression Asymmetry and Texture Evolution of a Rare-Earth-Containing Magnesium Alloy Sheet, ZEK100, at Different Strain Rates and Temperatures: Experiments and Modeling

August 1, 2017
Author(s)
Saadi A. Habib, Akhtar S. Khan, Thomas H. Gnaupel-Herold, Jeffrey T. Lloyd, Scott E. Schoenfeld
Mechanical responses and texture evolution of rare earth containing magnesium alloy, ZEK100, sheet are measured under uniaxial (tension-compression) loadings along the rolling direction (RD), 45° to rolling direction (DD), transverse direction (TD) and

Residual Stresses in Flow Drill Screwdriving of Aluminium Alloy Sheets

June 27, 2016
Author(s)
Justin L. Milner, Thomas H. Gnaeupel-Herold, Jamie D. Skovron
With an increase in fuel economy standards and the need for reducing emissions set for the automotive sector, has increased the demand for lightweight vehicles. It is well known that the single heaviest component of a passenger vehicle is the body