scholarly journals Development of Measurement Technique of Stress Field of Two Dimensional Polymer Flow

1996 ◽  
Vol 16 (Supplement2) ◽  
pp. 115-116
Author(s):  
Dai KITAHARA ◽  
Nobuyuki YAKO ◽  
Keiji HOSOKAWA ◽  
Tsutomu TAKAHASHI ◽  
Masataka SHIRAKASHI
Keyword(s):  
Stress Field ◽  
Measurement Technique ◽  
Two Dimensional ◽  
Polymer Flow

Modeling of a Beam and a Rotor with an Edge Crack Using Dissimilar Elements

2003 ◽  
Vol 9 (10) ◽  
pp. 1159-1187 ◽  
Author(s):  
A. Nandi ◽  
S. Neogy
Keyword(s):  
Finite Elements ◽  
Stress Field ◽  
Edge Crack ◽  
Three Dimensional ◽  
Transition Element ◽  
Two Dimensional ◽  
Cracked Beam ◽  
One Dimensional ◽  
Beam Elements ◽  
Dimensional Plane

Vibration-based diagnostic methods are used for the detection of the presence of cracks in beams and other structures. To simulate such a beam with an edge crack, it is necessary to model the beam using finite elements. Cracked beam finite elements, being one-dimensional, cannot model the stress field near the crack tip, which is not one-dimensional. The change in neutral axis is also not modeled properly by cracked beam elements. Modeling of such beams using two-dimensional plane elements is a better approximation. The best alternative would be to use three-dimensional solid finite elements. At a sufficient distance away from the crack, the stress field again becomes more or less one-dimensional. Therefore, two-dimensional plane elements or three-dimensional solid elements can be used near the crack and one-dimensional beam elements can be used away from the crack. This considerably reduces the required computational effort. In the present work, such a coupling of dissimilar elements is proposed and the required transition element is formulated. A guideline is proposed for selecting the proper dimensions of the transition element so that accurate results are obtained. Elastic deformation, natural frequency and dynamic response of beams are computed using dissimilar elements. The finite element analysis of cracked rotating shafts is complicated because of the fact that elastic deformations are superposed on the rigid-body motion (rotation about an axis). A combination of three-dimensional solid elements and beam elements in a rotating reference is proposed here to model such rotors.

Two-dimensional measurement technique for birefringence vector distributions: data processing and experimental verification

1999 ◽  
Vol 38 (11) ◽  
pp. 2216 ◽  
Author(s):  
Yongchang Zhu ◽  
Takehiro Koyama ◽  
Tatsuo Takada ◽  
Yoshihiro Murooka ◽  
Toshihisa Otsuka
Keyword(s):  
Data Processing ◽  
Measurement Technique ◽  
Experimental Verification ◽  
Two Dimensional ◽  
Dimensional Measurement

GROWTH HILLOCKS ON THE {100} FACES OF L-ARGININE PHOSPHATE MONOHYDRATE SINGLE CRYSTALS INVESTIGATED BY ATOMIC FORCE MICROSCOPY

2004 ◽  
Vol 11 (01) ◽  
pp. 71-75
Author(s):  
Y. L. GENG ◽  
D. XU ◽  
D. L. SUN ◽  
X. Q. WANG ◽  
G. H. ZHANG ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Stress Field ◽  
Single Crystals ◽  
Liquid Flow ◽  
Two Dimensional ◽  
Characteristic Structure ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dislocation Sources ◽  
Extra Stress

Growth hillocks on the {100} faces of L-arginine phosphate monohydrate (LAP) single crystals grown at 25°C and at a supersaturation of 0.32 have been discussed. The typical dislocation growth hillocks are lopsided and elongate along the b direction. The dislocation sources are probably caused by the extra stress field which is introduced by the hollow cavities distributing on the steps and hillocks generated by the two-dimensional nucleus. The elongated shape is due to the characteristic structure of the LAP crystal. Apart from that, the formation of the lopsided growth hillocks is explained by the liquid flow theory.

Calculation of the effect of polymer additive in a converging flow

1987 ◽  
Vol 178 ◽  
pp. 423-440 ◽  
Author(s):  
G. Ryskin
Keyword(s):  
Stress Field ◽  
Channel Flow ◽  
Molecular Model ◽  
Two Dimensional ◽  
Polymer Additive ◽  
Polymer Molecules ◽  
Conical Channel ◽  
Proposed Model ◽  
Converging Flow ◽  
Good Agreement

The conical-channel flow of a dilute polymer solution is investigated theoretically. The stress field due to polymer additive is calculated using a new molecular model, based on the physical picture of the polymer molecules unravelling in strong flows and Batchelor's theory for the stress in a suspension of elongated particles. Good agreement is obtained with the experimental results of James & Saringer (1980). The absence of a significant polymer effect in a two-dimensional case (the wedge-channel flow), observed by the same authors (James & Saringer 1982a), is also explained. The fundamental differences between the proposed model and the elastic-dumbbell models are discussed.

scholarly journals A simple stress-based cliff-calving law

2019 ◽  
Vol 13 (9) ◽  
pp. 2475-2488 ◽  
Author(s):  
Tanja Schlemm ◽  
Anders Levermann
Keyword(s):  
Stress Field ◽  
Yield Stress ◽  
Sea Level ◽  
Water Depth ◽  
Stability Limit ◽  
Two Dimensional ◽  
Loss Mechanism ◽  
Relative Water ◽  
Ice Failure ◽  
Dry Water

Abstract. Over large coastal regions in Greenland and Antarctica the ice sheet calves directly into the ocean. In contrast to ice-shelf calving, an increase in calving from grounded glaciers contributes directly to sea-level rise. Ice cliffs with a glacier freeboard larger than ≈100 m are currently not observed, but it has been shown that such ice cliffs are increasingly unstable with increasing ice thickness. This cliff calving can constitute a self-amplifying ice loss mechanism that may significantly alter sea-level projections both of Greenland and Antarctica. Here we seek to derive a minimalist stress-based parametrization for cliff calving from grounded glaciers whose freeboards exceed the 100 m stability limit derived in previous studies. This will be an extension of existing calving laws for tidewater glaciers to higher ice cliffs. To this end we compute the stress field for a glacier with a simplified two-dimensional geometry from the two-dimensional Stokes equation. First we assume a constant yield stress to derive the failure region at the glacier front from the stress field within the glacier. Secondly, we assume a constant response time of ice failure due to exceedance of the yield stress. With this strongly constraining but very simple set of assumptions we propose a cliff-calving law where the calving rate follows a power-law dependence on the freeboard of the ice with exponents between 2 and 3, depending on the relative water depth at the calving front. The critical freeboard below which the ice front is stable decreases with increasing relative water depth of the calving front. For a dry water front it is, for example, 75 m. The purpose of this study is not to provide a comprehensive calving law but to derive a particularly simple equation with a transparent and minimalist set of assumptions.

Sign in / Sign up

Export Citation Format

Share Document