U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Stephen Langer (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 54

Analytical and Numerical Analyses for Two-Dimensional Stress Transfer

October 12, 2021
Author(s)
C H. Hsueh, P Becher, Lin-Sien H. Lum, Stephen A. Langer, W Carter
Both analytical modeling and numerical simulations were performed to analyze the stress transfer in platelet-reinforced composites in a two-dimensional sense. In the two-dimensional model, an embedded elongate plate bonded to a matrix along its length

Effects of Bond Coat Surface-Roughness on Residual Stresses of Thermal Barrier Coating Systems

October 12, 2021
Author(s)
C H. Hsueh, J Haynes, M Lance, P Becher, M Ferber, Stephen A. Langer, W Carter, W R. Cannon, Lin-Sien H. Lum
The adherence of plasma-sprayed thermal barrier coatings (TBCs) is dependent on mechanical interlocking at the interface between the ceramic top coat and the underlying metallic bond coat. A rough bond coat surface is required in order to establish

Simulating Thermal Response of EB-PVD Thermal Barrier Coating Microstructures

October 12, 2021
Author(s)
M Bartsch, U Schulz, J M. Dorvaux, O Lavigne, Lin-Sien H. Lum, Stephen A. Langer
As ceramic thermal barrier coatings (TBC) are used in more critical applications in advanced engines, knowing basic physiproperties of TBC's is essential for design and reliability assessment. In particular, knowledge of thermal conductivity is cruciin

Calculating Voxel-Polyhedron Intersections for Meshing Images

October 9, 2021
Author(s)
Stephen A. Langer, Andrew C.E. Reid
Finite element meshes constructed from 3D images are useful in materials science and medical applications when it is necessary to model the actual geometry of a sample, rather than an idealized approximation of it. Constructing the mesh involves computing

Spatial strain correlations, machine learning, and deformation history in crystal plasticity

May 16, 2019
Author(s)
Andrew C. Reid, Stefanos Papanikolaou, Hengxu Song, Erik Van der Giessen, Stephen A. Langer, Michail Tzimas
Digital image correlation (DIC) is a well-established, non-invasive technique for tracking and quantifying the deformation of mechanical samples under test. While it provides an obvious way to observe incremental and aggregate displacement information, it

gtklogger: A Tool For Systematically Testing Graphical User Interfaces

August 20, 2015
Author(s)
Stephen A. Langer, Faical Y. Congo, Andrew C. Reid, Rhonald Lua, Valerie R. Coffman
We describe a scheme for systematically testing the operation of a graphical user interface. The scheme provides a capability for generating event logs, which are recordings of a user session with the interface. These logs can be annotated with assertion

OOF3D: An Image-Based Finite Element Solver for Materials Science

March 28, 2012
Author(s)
Valerie R. Coffman, Andrew C. Reid, Stephen A. Langer, Gunay Dogan
Recent advances in experimental techniques (micro CT scans, automated serial sectioning, electron back-scatter diffraction, synchrotron radiation x-rays) have made it possible to characterize the full, three dimensional structure of real materials. Such

Modeling Microstructures with OOF2

September 1, 2009
Author(s)
Andrew C. Reid, Rhonald Lua, R E. Garcia, Valerie R. Coffman, Stephen A. Langer
OOF2 is a program for computing the properties and behavior of material microstructures, beginning with an image of the microstructural geometry. OOF2 uses finite elements, but is designed to be used by materials scientists with little or no finite element