Unified scenario for the morphology of crack paths in two-dimensional disordered solids

The impact response of HMX/Estane, a Polymer Bonded Explosive (PBX), is analyzed under two-dimensional plane-strain conditions using a cohesive finite element method (CFEM). The framework enables the consideration of arbitrary microstructures. The binder polymer is modeled as a viscoelastic material. The dependence of elastic modulus on temperature across the glass transition temperature Tg (= 233 K) is considered in the constitutive framework. Also, the HMX crystals are assumed to be elastic under the conditions analyzed. Cohesive elements are implemented throughout the microstructure, allowing explicit tracking of arbitrary crack paths through each constituent or interfaces between the constituents. A contact algorithm used to track and account for the interactions between failed crack surfaces. The simulations capture the failure characteristics observed experimentally at temperatures ranging from below to above Tg of the polymer.

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Stress Intensity Factors and Crack Paths for Cracks in Photoelastic Motor Grain Models

Recent Advances in Solids and Structures ◽

10.1115/imece2002-32078 ◽

2002 ◽

Author(s):

C. W. Smith ◽

D. M. Constantinescu ◽

C. T. Liu

Keyword(s):

Stress Intensity ◽

Computational Analysis ◽

Tensile Tests ◽

Small Radius ◽

Two Dimensional ◽

Intensity Factors ◽

Photoelastic Method ◽

Shear Modes ◽

Tip Radius ◽

Crack Paths

Computational analysis and two dimensional tensile tests on single motor grain fins suggest that cracks in fin tips are most likely to originate at the coalescence of the fin end tip radius with a small radius emanating from the side of the fin. Prior studies have indicated that under internal pressure, cracks on the fin axis are subject to similar stress peaks and may grow more readily than the former types due to an absence of shear modes. The present study focuses upon two types of cracks emanating from the former location called “off-axis” cracks and attempts to differentiate from the two types by their paths and SIF values, determined by the frozen stress photoelastic method.

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31P MAS Refocused INADEQUATE Spin−Echo (REINE) NMR Spectroscopy: RevealingJCoupling and Chemical Shift Two-Dimensional Correlations in Disordered Solids

Journal of the American Chemical Society ◽

10.1021/ja902238s ◽

2009 ◽

Vol 131 (33) ◽

pp. 11861-11874 ◽

Cited By ~ 38

Author(s):

Paul Guerry ◽

Mark E. Smith ◽

Steven P. Brown

Keyword(s):

Nmr Spectroscopy ◽

Chemical Shift ◽

Spin Echo ◽

Two Dimensional ◽

Disordered Solids

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Spectrophotometric measurements of objective-prism spectra

Symposium - International Astronomical Union ◽

10.1017/s007418090005333x ◽

1966 ◽

Vol 24 ◽

pp. 118-119

Author(s):

Th. Schmidt-Kaler

Keyword(s):

Progress Report ◽

Two Dimensional ◽

Objective Prism ◽

Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

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Introductory paper

Symposium - International Astronomical Union ◽

10.1017/s0074180900053031 ◽

1966 ◽

Vol 24 ◽

pp. 3-5

Author(s):

W. W. Morgan

Keyword(s):

Line Intensity ◽

Classification Scheme ◽

Two Dimensional ◽

Spectral Classification ◽

Dimensional Array ◽

Rr Lyrae ◽

Metallic Line ◽

Introductory Paper ◽

Parameter Varying ◽

Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

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A one-dimensional self-gravitating stellar gas

Symposium - International Astronomical Union ◽

10.1017/s0074180900105261 ◽

1966 ◽

Vol 25 ◽

pp. 46-48 ◽

Cited By ~ 2

Author(s):

M. Lecar

Keyword(s):

Gravitational Field ◽

Phase Space ◽

Motion Picture ◽

Space Distribution ◽

Two Dimensional ◽

One Dimensional ◽

Phase Space Distribution ◽

Dimensional Phase Space ◽

The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

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Analysis of the 9th November 1990 flare

International Astronomical Union Colloquium ◽

10.1017/s025292110006454x ◽

2000 ◽

Vol 179 ◽

pp. 229-232

Author(s):

Anita Joshi ◽

Wahab Uddin

Keyword(s):

Image Processing ◽

Two Dimensional ◽

Temporal Behaviour ◽

Contour Maps ◽

Dimensional Measurements ◽

Processing Software ◽

Image Processing Software

AbstractIn this paper we present complete two-dimensional measurements of the observed brightness of the 9th November 1990Hαflare, using a PDS microdensitometer scanner and image processing software MIDAS. The resulting isophotal contour maps, were used to describe morphological-cum-temporal behaviour of the flare and also the kernels of the flare. Correlation of theHαflare with SXR and MW radiations were also studied.

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