Skip Nav Destination
Close Modal
Update search
Filter
- Title
- Author
- Author Affiliations
- Full Text
- Abstract
- Keyword
- DOI
- ISBN
- ISBN-10
- ISSN
- EISSN
- Issue
- Volume
- References
- Conference Volume
- Paper No
Filter
- Title
- Author
- Author Affiliations
- Full Text
- Abstract
- Keyword
- DOI
- ISBN
- ISBN-10
- ISSN
- EISSN
- Issue
- Volume
- References
- Conference Volume
- Paper No
Filter
- Title
- Author
- Author Affiliations
- Full Text
- Abstract
- Keyword
- DOI
- ISBN
- ISBN-10
- ISSN
- EISSN
- Issue
- Volume
- References
- Conference Volume
- Paper No
Filter
- Title
- Author
- Author Affiliations
- Full Text
- Abstract
- Keyword
- DOI
- ISBN
- ISBN-10
- ISSN
- EISSN
- Issue
- Volume
- References
- Conference Volume
- Paper No
Filter
- Title
- Author
- Author Affiliations
- Full Text
- Abstract
- Keyword
- DOI
- ISBN
- ISBN-10
- ISSN
- EISSN
- Issue
- Volume
- References
- Conference Volume
- Paper No
Filter
- Title
- Author
- Author Affiliations
- Full Text
- Abstract
- Keyword
- DOI
- ISBN
- ISBN-10
- ISSN
- EISSN
- Issue
- Volume
- References
- Conference Volume
- Paper No
NARROW
Format
Journal
Article Type
Conference Series
Subject Area
Topics
Date
Availability
1-20 of 20
K. L. Johnson
Close
Follow your search
Access your saved searches in your account
Would you like to receive an alert when new items match your search?
Sort by
Journal Articles
S. A. Brauer, W. R. Whittington, K. L. Johnson, B. Li, H. Rhee, P. G. Allison, C. K. Crane, M. F. Horstemeyer
Article Type: Research-Article
J. Eng. Mater. Technol. April 2017, 139(2): 021013.
Paper No: MATS-16-1127
Published Online: February 9, 2017
Abstract
An investigation of the mechanical strain rate, inelastic behavior, and microstructural evolution under deformation for an as-cast pearlitic gray cast iron (GCI) is presented. A complex network of graphite, pearlite, steadite, and particle inclusions was stereologically quantified using standard techniques to identify the potential constituents that define the structure–property relationships, with the primary focus being strain rate sensitivity (SRS) of the stress–strain behavior. Volume fractions for pearlite, graphite, steadite, and particles were determined as 74%, 16%, 9%, and 1%, respectively. Secondary dendrite arm spacing (SDAS) was quantified as 22.50 μ m ± 6.07 μ m. Graphite flake lengths and widths were averaged as 199 μ m ± 175 μ m and 4.9 μ m ± 2.3 μ m, respectively. Particle inclusions comprised of manganese and sulfur with an average size of 13.5 μ m ± 9.9 μ m. The experimental data showed that as the strain rate increased from 10 −3 to 10 3 s −1 , the averaged strength increased 15–20%. As the stress state changed from torsion to tension to compression at a strain of 0.003 mm/mm, the stress asymmetry increased ∼470% and ∼670% for strain rates of 10 −3 and 10 3 s −1 , respectively. As the strain increased, the stress asymmetry differences increased further. Coalescence of cracks emanating from the graphite flake tips exacerbated the stress asymmetry differences. An internal state variable (ISV) plasticity-damage model that separately accounts for damage nucleation, growth, and coalescence was calibrated and used to give insight into the damage and work hardening relationship.
Journal Articles
Journal:
Journal of Biomechanical Engineering
Article Type: Research-Article
J Biomech Eng. February 2014, 136(2): 021023.
Paper No: BIO-13-1412
Published Online: February 5, 2014
Abstract
The present study, through finite element simulations, shows the geometric effects of a bioinspired solid on pressure and impulse mitigation for an elastic, plastic, and viscoelastic material. Because of the bioinspired geometries, stress wave mitigation became apparent in a nonintuitive manner such that potential real-world applications in human protective gear designs are realizable. In nature, there are several toroidal designs that are employed for mitigating stress waves; examples include the hyoid bone on the back of a woodpecker's jaw that extends around the skull to its nose and a ram's horn. This study evaluates four different geometries with the same length and same initial cross-sectional diameter at the impact location in three-dimensional finite element analyses. The geometries in increasing complexity were the following: (1) a round cylinder, (2) a round cylinder that was tapered to a point, (3) a round cylinder that was spiraled in a two dimensional plane, and (4) a round cylinder that was tapered and spiraled in a two-dimensional plane. The results show that the tapered spiral geometry mitigated the greatest amount of pressure and impulse (approximately 98% mitigation) when compared to the cylinder regardless of material type (elastic, plastic, and viscoelastic) and regardless of input pressure signature. The specimen taper effectively mitigated the stress wave as a result of uniaxial deformational processes and an induced shear that arose from its geometry. Due to the decreasing cross-sectional area arising from the taper, the local uniaxial and shear stresses increased along the specimen length. The spiral induced even greater shear stresses that help mitigate the stress wave and also induced transverse displacements at the tip such that minimal wave reflections occurred. This phenomenon arose although only longitudinal waves were introduced as the initial boundary condition (BC). In nature, when shearing occurs within or between materials (friction), dissipation usually results helping the mitigation of the stress wave and is illustrated in this study with the taper and spiral geometries. The combined taper and spiral optimized stress wave mitigation in terms of the pressure and impulse; thus providing insight into the ram's horn design and woodpecker hyoid designs found in nature.
Proceedings Papers
Proc. ASME. WTC2005, World Tribology Congress III, Volume 1, 189-190, September 12–16, 2005
Paper No: WTC2005-64177
Abstract
The so-called JKR theory of adhesion between elastic spheres in contact (Johnson, Kendall & Roberts 1971, Sperling 1964) has been widely used in micro-tribology. In this paper the theory is extended to solids of general shape and curvature. It is assumed that the area of contact is elliptical which turns out to be approximately true, though the eccentricity is different from that for non-adhesive contact. Closed form expressions are found for the variation with load of contact radius and displacement, as a function of the ratio of principal relative curvatures of the two bodies in contact. The pull-off force is found to decrease with increasing eccentricity from its value of 3πΔγR/2 in the case of contact of spheres of radius R.
Journal Articles
Journal:
Journal of Applied Mechanics
Article Type: Book Reviews
J. Appl. Mech. March 1993, 60(1): 255.
Published Online: March 1, 1993
Topics:
Rolling contact
Journal Articles
Journal:
Journal of Tribology
Article Type: Discussions
J. Tribol. January 1992, 114(1): 9–10.
Published Online: January 1, 1992
Journal Articles
Journal:
Journal of Tribology
Article Type: Discussions
J. Tribol. October 1987, 109(4): 655.
Published Online: October 1, 1987
Topics:
Elastohydrodynamic lubrication
Journal Articles
Journal:
Journal of Applied Mechanics
Article Type: Research Papers
J. Appl. Mech. March 1987, 54(1): 1–7.
Published Online: March 1, 1987
Abstract
Rollers loaded above their shakedown limit are known to undergo cumulative plastic shearing of their surface layers. An approximate analysis of this deformation by Merwin and Johnson (1963) was in good accord with experiments, but a recent finite-element calculation by Bhargava et al. (1984) predicted much larger deformations. This paper investigates the discrepancy and presents an alternative analysis which supports that by finite-elements.
Journal Articles
Journal:
Journal of Tribology
Article Type: Book Reviews
J. Tribol. October 1986, 108(4): 659.
Published Online: October 1, 1986
Topics:
Contact mechanics
Journal Articles
Journal:
Journal of Tribology
Article Type: Research Papers
J. Tribol. July 1979, 101(3): 266–273.
Published Online: July 1, 1979
Abstract
The performance of traction drives depends to a large extent on the rheological properties of the fluid in the EHL contact. Through the use of the recently proposed J + T constitutive equation, the influence of elastic effects in the fluids is examined. The results were compared with those obtained from conventional analysis. It is shown that essentially three regions of influence exist. For small values of spin and side slip the elastic effects in the fluid dominate and no consideration of the spin and side slip is required. At higher values of spin and side slip the elastic effect still exists but slip is influenced by the spin and slide slip. At still higher values of side slip and spin, the elastic effects in the fluid may be neglected. The various boundaries of the regions of influence depend on the aspect ratio of the contact.
Journal Articles
Journal:
Journal of Tribology
Article Type: Discussions
J. Tribol. July 1979, 101(3): 274.
Published Online: July 1, 1979
Journal Articles
Journal:
Journal of Tribology
Article Type: Discussions
J. Tribol. July 1978, 100(3): 416–417.
Published Online: July 1, 1978
Journal Articles
Journal:
Journal of Tribology
Article Type: Discussions
J. Tribol. July 1974, 96(3): 407.
Published Online: July 1, 1974
Journal Articles
Journal:
Journal of Tribology
Article Type: Discussions
J. Tribol. October 1973, 95(4): 425.
Published Online: October 1, 1973
Journal Articles
Journal:
Journal of Tribology
Article Type: Discussions
J. Tribol. January 1970, 92(1): 87.
Published Online: January 1, 1970
Journal Articles
Journal:
Journal of Tribology
Article Type: Discussions
J. Tribol. January 1970, 92(1): 95.
Published Online: January 1, 1970
Journal Articles
Journal:
Journal of Fluids Engineering
Article Type: Discussions
J. Fluids Eng. September 1965, 87(3): 711.
Published Online: September 1, 1965
Topics:
Oscillations
Journal Articles
Journal:
Journal of Applied Mechanics
Article Type: Technical Briefs
J. Appl. Mech. June 1964, 31(2): 338–340.
Published Online: June 1, 1964
Journal Articles
Journal:
Journal of Fluids Engineering
Article Type: Discussions
J. Fluids Eng. March 1963, 85(1): 113.
Published Online: March 1, 1963
Journal Articles
Journal:
Journal of Applied Mechanics
Article Type: Discussions
J. Appl. Mech. December 1962, 29(4): 763.
Published Online: December 1, 1962
Journal Articles
Journal:
Journal of Fluids Engineering
Article Type: Research Papers
J. Fluids Eng. December 1960, 82(4): 899–900.
Published Online: December 1, 1960