Ronald Goulet
University of Tennessee at Chattanooga
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Featured researches published by Ronald Goulet.
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science | 1996
Ronald Goulet; Todd S. Gross; D.A. Mendelsohn
Interference of the asperities on a crack loaded in pure, remote shear wedges the crack faces open, thereby inducing a mode I stress intensity factor (SIF). The interference also shields the crack tip from the applied mode II SIF. Three-illumination beam, phase-shifted speckle interferometry was used to measure the three-dimensional incremental displacement fields in a 7×11 mm area around a mode I fatigue precrack in a Al 7075 specimen loaded in 94 increments of increasing shear. The displacement fields were accumulated relative to the unloaded state by sampling at appropriate locations in the incremental fields to optimize spatial resolution and compensate for large rigid body motions. The induced mode I SIF and the effective mode II SIF were estimated from the crack tip shear displacement (CTSD) and crack tip opening displacement (CTOD). A digitized fracture surface profile was numerically shifted according to the experimentally measured crack face displacements to determine the locations of fracture surface interference as a function of applied load.
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 1998
D.A. Mendelsohn; Todd S. Gross; Ronald Goulet; M Zhouc
Abstract This paper presents the preliminary results of a technique for estimating the contact stress distribution on the rough surfaces of cracks which are partially closed and loaded in shear. Phase shifted speckle interferrometric measurements of the crack face opening and sliding displacements of a crack in a four-point-bend mixed-mode fracture specimen under quasi-static cyclic loading are used as the initial data. An iterative computational process determines acceptable fits of the initial displacement data and the corresponding crack face contact stresses, which are found from a numerical model of the specimen and loading. Contact stress results are presented from one specimen at two load increments which suggest that the roughness causes an increase in the contact length compared to flat and smooth surfaces. More importantly, as the extent of sliding increases, the effective frictional resistance becomes localized and is a strong function of position along the contact. This cannot be modeled by Coulomb friction with a single value of the coefficient of friction. These are the first results of their kind ever presented for the local displacement and contact stress distributions across rough interacting fracture surfaces.
Engineering Fracture Mechanics | 2001
D.A. Mendelsohn; Todd S. Gross; L.-J. Young; F. Chen; Ronald Goulet
Abstract This paper presents a numerical study of specimen geometry and load frame/specimen interaction of a four-point-bend mixed mode fracture specimen. The aspect ratio of the specimen, the stick/slip condition between the loading pin and specimen, and the lateral and rotational restraint of the load train all have a potentially significant effect on the mode I and mode II crack tip fields in the specimen. These effects are illustrated by the dependence of the uncracked stress fields, mode I and mode II stress intensity factors, and crack opening and sliding displacements on geometric parameters and load train restraint conditions.
SPIE's 1995 International Symposium on Optical Science, Engineering, and Instrumentation | 1995
David W. Watt; Ronald Goulet; Todd S. Gross
A three illumination beam, phase-shifted interferometry system is used to measure 3D surface deformation fields to study the mechanics of cracks loaded in shear. The interferometer, which is mounted to the actuator of a servohydraulic loading machine, is augmented with a piezoelectric phase shifter to obtain a sequance of differential phase maps over small load increments. This avoids problems with speckle decorrelation and provides more detailed information about the phenomena of interest. The displacement fields were accumulated relative to the unloaded state by sampling at appropriate locations in the incremental fields to optimize spatial resolution and compensate for large rigid body motions. Features of the effect of fracture surface interference on a shear-loaded crack inferred from the displacement fields are described.
Journal of Shoulder and Elbow Surgery | 2002
M.R. Iannotti; L.A. Crosby; P. Stafford; Greg Grayson; Ronald Goulet
Critical Reviews in Biomedical Engineering | 2000
Paul Stafford; Ronald Goulet; Brent Norris
2010 Annual Conference & Exposition | 2010
Ronald Goulet
2002 Annual Conference | 2002
Joseph Owino; Ronald Goulet
2007 Annual Conference & Exposition | 2007
Cecelia Wigal; Ignatius Fomunung; Edwin Foster; Ronald Goulet
2003 Annual Conference | 2003
Ronald Goulet