|
Dempsey, J. P.
Overview
| Works: | 20
works in
27
publications in
1
language and
217
library holdings
|
| Roles: | Editor |
| Classifications: | ta714.5,
620.41 |
Most widely held works by
J. P Dempsey
Freeze/thaw conditioning of water treatment residuals by Anthony G Collins (
Book
)
2
editions published
in
2000
in
English
and held by
6
libraries
worldwide
POAC '05, Potsdam, NY, USA : 18th International Conference on Port and Ocean Engineering under Arctic Conditions, June 26-30, 2005 : proceedings by International Conference on Port and Ocean Engineering under Arctic Conditions (
Book
)
1
edition published
in
2005
in
English
and held by
3
libraries
worldwide
On the stress singularities in the plane elasticity of the composite wedge by J. P Dempsey (
Book
)
2
editions published
in
1978
in
English
and held by
2
libraries
worldwide
Ice mechanics : Symposium : Summer meeting : Papers(
Book
)
1
edition published
in
1995
in
English
and held by
2
libraries
worldwide
A viscoelastic fictitious crack model for the fracture of sea ice by S. V Mulmule (
Book
)
1
edition published
in
1997
in
English
and held by
1
library
worldwide
The fracture of sea ice is modeled using a viscoelastic fictitious crack (cohesive zone) model. The sea ice is modeled as a linear viscoelastic material. The fictitious crack model is implemented via the weight function method. The associated stress-separation curve can be rate dependent. The impact of assuming viscoelastic behavior in the bulk as opposed to elastic behavior is studied. Results from the model are compared to the available exact results for various test cases. The model is applied to a large scale insitu sea ice fracture test. Various implications of such applications are pointed out. This viscoelastic fictitious crack model is found to be a promising tool in investigations pertaining to the fracture of sea ice.
A lattice model for viscoelastic fracture by Leonid I Slepyan (
Book
)
1
edition published
in
1999
in
English
and held by
1
library
worldwide
A plane, periodic, square-cell lattice is considered, consisting of point particles connected by mass-less viscoelastic bonds. Homogeneous and inhomogeneous problems for steady-state semi-infinite crack propagation in an unbounded lattice and lattice strip are studied. Expressions for the local-to-global energy-release-rate ratios, stresses and strains of the breaking bonds as well as the crack opening displacement are derived. Comparative results are obtained for homogeneous viscoelastic materials, elastic lattices and homogeneous elastic materials. The influences of viscosity, the discrete structure, cell size, strip width and crack speed on the wave/viscous resistances to crack propagation are revealed. Some asymptotic results related to an important asymptotic case of large viscosity (on a scale relative to the lattice cell) are shown. Along with dynamic crack propagation, a theory for a slow crack in a viscoelastic lattice is derived.
Laboratory And Field Scale Fracture Of Sea Ice(
Book
)
1
edition published
in
1996
in
English
and held by
1
library
worldwide
This report contains details of laboratory and field scale studies carried out to study fracture of sea ice. The field scale studies were carried out in six field trips on in-situ arctic sea ice. Lab scale studies were carried out on the samples obtained from cores taken from the sea ice during the field trips. The details of the experimental method and portable loading system specifically designed for these tests are given. The first two field trips are analyzed to reveal the size effect on the fracture of S1 freshwater and S2 sea ice. The analysis is carried out using size effect laws. To analyze the creep-recovery and cyclic loading experiment, a model based on the nonlinear theory of viscoelasticity is proposed. It is shown that the model is capable of predicting the load-deformation paths under simple loading histories.
Size And Rate Effects on the Fracture of Sea Ice(
Book
)
1
edition published
in
1996
in
English
and held by
1
library
worldwide
This report contains the details of the experimental study as well as the theory applied to study the rate and size effect on the fracture of sea ice. To study the fracture of ice, experiments were carried out on a semi-circular bend fracture geometry. The test program formed a lab scale study to complement the in-situ large-scale sea ice fracture tests. The ice used was shipped back in the form of cores from the arctic tests. Two directions of fracture, parallel to the c-axis (optical axis) and perpendicular to the c-axis are studied. To examine the rate effect, a Reversed Direct Stress (RDS) device was modified to suit rectangular shaped test specimens. The details of modifications are given. Ice samples were subjected to creep-recovery loading and allowed to recover. The resultant time dependent deformations were analyzed using nonlinear viscoelastic theory. Experimental results as well as the details of the nonlinear viscoelastic models are given.
Effects of Specimen Size and Geometry Effects, Loading Rate and Microstructure on the Tensile Fracture of Saline Ice(
Book
)
1
edition published
in
1995
in
English
and held by
1
library
worldwide
This report contains the details of the experimental program on large-scale in-situ arctic sea ice tests. A total of six field trips were completed. The experiments conducted included flexure tests, fracture tests as well as tests where the ice specimen was subjected to cyclic and creep-recovery type loading. A maximum size range ratio of 1 to 160 was accomplished in fracture tests specifically to study the effect of variation in size. About six different geometries, (3 point bend, cantilever beam, griffith crack geometry, reverse taper geometry, square plate geometry, and rectangular plate geometry) were utilized to study the effect of geometry on tensile fracture. Since the field trips occurred in three seasons, seasonal variations in ice properties including sea ice thickness variation were studied. The ice types were S1 freshwater ice, S2 freshwater ice, S2 sea ice, thin lead ice and multiyear sea ice.
IUTAM : Scaling Laws in Ice Mechanics and Ice Dynamics, University of Alaska Fairbanks, June 13-16, 2000, Fairbanks : [preprints by IUTAM Symposium on Scaling Laws in Ice Mechanics and Ice Dynamics (
Book
)
1
edition published
in
2000
in
English
and held by
1
library
worldwide
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Alternative Names
Dempsey, John P.
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