Determining equations of processes of small-curvature deformation for materials not satisfying the isotropy postulate

1988 ◽  
Vol 20 (10) ◽  
pp. 1271-1276 ◽  
Author(s):  
B. I. Koval'chuk ◽  
V. V. Kosarchuk
Keyword(s):  
Small Curvature ◽  
Curvature Deformation

scholarly journals Vortex motion on surfaces of small curvature

2013 ◽  
Vol 339 ◽  
pp. 570-587 ◽  
Author(s):  
Daniele Dorigoni ◽  
Maciej Dunajski ◽  
Nicholas S. Manton
Keyword(s):  
Vortex Motion ◽  
Small Curvature

Bending Stiffener Design Through Structural Optimization

2009 ◽  
Author(s):  
Rafael Loureiro Tanaka ◽  
Lauro Massao Yamada da Silveira ◽  
Joa˜o Paulo Zi´lio Novaes ◽  
Eduardo Esterqui de Barros ◽  
Clo´vis de Arruda Martins
Keyword(s):  
Optimization Problem ◽  
Design Procedure ◽  
Complex Task ◽  
Load Case ◽  
Shear Forces ◽  
Design Variables ◽  
Curvilinear Coordinate ◽  
Regular Design ◽  
Curvature Deformation ◽  
Flexible Risers

Bending stiffeners are very important ancillary equipments of umbilicals or flexible risers, since they protect the lines from overbending. Their design however is a complex task, since many load cases must be taken into account; the structure itself has a section that is variable with curvilinear coordinate. To aid the designer in this task, optimization algorithms can be used to automate the search for the best design. In this work an optimization algorithm is applied to the design of the bending stiffener. First, a bending stiffener model is created, which is capable of simulating different load case conditions and provide, as output, results of interest such as maximum curvature, deformation along the stiffener, shear forces and so on. Then, a bending stiffener design procedure is written as an optimization problem and, for that, objective function, restrictions and design variables defined. Study cases were performed, comparing a regular design with its optimized counterpart, under varying conditions.

Long-term results of pyloroplasty

1934 ◽  
Vol 30 (7-8) ◽  
pp. 720-726
Author(s):  
D. S. Klebanov
Keyword(s):  
Operative Treatment ◽  
Central Point ◽  
Long Term Results ◽  
Small Curvature ◽  
Therapeutic Method ◽  
Theoretical Substantiation

The theoretical substantiation of pyloroplasty as a therapeutic method in adults is based on the provisions, which are still very problematic today. Russian authors (Breitsev, Grekov et al.), who first proposed this operation in adults, set indications for this kind of intervention very broadly and considered it indicated not only for pylorospasm without visible ulcer, but also for ulcers of the small curvature and for ulcers of the 12th bowel. At the same time these authors proceeded from the position that pylorospasm is the central point in the pathogenesis and course of ulcers and they considered its elimination to be very important in the operative treatment of ulcers.

scholarly journals Strain and Curvature Stability Enhanced SMF Introduction

2017 ◽  
Vol 6 (1) ◽  
pp. 63
Author(s):  
S. Makouei
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Design Method ◽  
Single Mode ◽  
Effective Area ◽  
Refractive Index Profile ◽  
Curvature Radius ◽  
Geometrical Parameters ◽  
Small Curvature ◽  
Bending Loss

In this paper, the strain insensitive single mode optical fiber with low nonlinear effects and ultra low bending loss (BL), appropriate for small curvature radius installation, is presented. The suggested design method is based on the reverse engineering which evaluates the refractive index profile considering proper mode field diameter (MFD) value. Then, so as to attain the desired bending loss and strain response for the optical fiber, the optimization tool of the evolutionary genetic algorithm (GA) is employed to determine the optical and geometrical parameters of the structure. In the first designed fiber, the calculations for BL, MFD, effective area (Aeff), and effective refractive index (neff) sensitivity to strain in the well-known wavelength of 1.55 µm are 0.0018 dB per each turn of 5 mm curvature radius, 8.53 µm, 58 µm2, and 4.5 × 10-8 µɛ-1, respectively. Furthermore, the effect of placing raised outer cladding in the fiber structure is investigated which exhibits the MFD of 8.63 µm, 0.0093 dB BL for single turn of 5 mm radius, and 87 µm2 Aeff at 1.55 µm. In this case the strain sensitivity of 6.7 × 10-8 µɛ-1 is calculated for the neff. The mentioned effective area is magnificently large in the domain of bend insensitive fibers. In the meantime, the designed structures are insensitive to strain which is a crucial feature in applications with small curvature radius.

scholarly journals Studying and improving intermediate rail fastening of rail transport

2019 ◽  
Vol 109 ◽  
pp. 00028
Author(s):  
Volodymyr Hovorukha
Keyword(s):  
Rail Transport ◽  
Railway Track ◽  
Small Radius ◽  
Working Capacity ◽  
Operational Parameters ◽  
Transverse Loading ◽  
Topical Problem ◽  
Railroad Transport ◽  
Small Curvature ◽  
Horizontal Loading

Topical problem concerning the improvement of intermediate rail fastening of a railway track of railroad transport as well as industrial and underground rail one has been considered taking into account peculiarities of operation in terms of curved sections of a route with small-radius curvature. Objective of the paper is to improve operational parameters of a railway track with extra small curvature radii in terms of railroad gauge adjustment. Operation of the components of intermediate rail fastening, being subject to intense wear and destruction due to the effect of great transverse and horizontal loading within the curved route sections with small-radius curvature, has been and analysed. Innovative engineering solutions to improve intermediate rail fastening have been proposed. Such peculiarity of the device of intermediate rail fastening provides increased durability and working capacity of rail fastening components in terms of considerable transverse loading within the route sections with small-radius curvature. The obtained results may be applied for underground and industrial rail transport as well as for railroad one.

Numerical Prediction of Failure within Small Curvature Bending of Advanced High Strength Steels

2015 ◽  
Vol 639 ◽  
pp. 419-426
Author(s):  
Ioannis Tsoupis ◽  
Marion Merklein
Keyword(s):  
Crack Initiation ◽  
Damage Mechanics ◽  
Numerical Study ◽  
Damage Model ◽  
High Strength Steels ◽  
High Strength ◽  
Continuum Damage Mechanics ◽  
Calibration Method ◽  
Damage Parameter ◽  
Small Curvature

Within this paper a numerical study of the Continuum Damage Mechanics based damage model Lemaitre in commercial software LS-DYNA is performed in order to correctly predict failure in terms of crack occurrence within small curvature bending of AHSS steels. A strain based calibration method is used for the effective adaption of the Lemaitre model to the bending operation, which is based on the comparison and adaption of the numerically calculated and the experimentally measured deformation field on the outer surface of the bent specimen. Within this method the material dependent damage parameter S is systematically varied in the simulation in order to represent maximum major strain. The new method is proved by numerical simulation of experiments provoking crack initiation using smaller bending radii. It can be shown that failure in terms of crack initiation can be correctly predicted by the model with the damage parameters, which were determined by the method of strain based calibration and an additional optimisation of the parameter Dc. Thus, within this study a user friendly and effective way for the application of Lemaitre damage model to small curvature bending processes of AHSS steels is developed.

Defective 2D Barcode Image Mosaic Method for Rotary Scanning Serial Image

2013 ◽  
Vol 397-400 ◽  
pp. 2248-2256
Author(s):  
Jia Jing Wang ◽  
Shu Sheng Zhang ◽  
Wei Ping He
Keyword(s):  
Measurement Precision ◽  
Image Mosaic ◽  
Feature Points ◽  
Local Entropy ◽  
Bar Code ◽  
Metal Parts ◽  
2D Barcode ◽  
Curvature Deformation ◽  
Splicing Efficiency ◽  
2D Bar Code

A mosaic method of based on rotational scan sequence cylindrical barcode which is suitable for metal parts is put forward, which combined the hardware and the software. Firstly, extract the feature points of each serial image based on scale-interaction of Marr wavelets. Then, get the optimal match of feature points with improved image local entropy. Lastly, complete the natural splice of the defect 2D bar code images through the algorithm of three interpolation and multi-resolution spline. The experimental results show that the algorithm could extract the feature points of consistent relative position and quantity after the processes of rotation, brightness, blur and nose, at the same time, assure the splicing efficiency and measurement precision of image mosaic. The method can also better finish the defect bar code recovery caused by curvature deformation.

scholarly journals RELATIVE LOCALITY IN CURVED SPACETIME

2013 ◽  
Vol 28 (22) ◽  
pp. 1350101 ◽  
Author(s):  
JERZY KOWALSKI-GLIKMAN ◽  
GIACOMO ROSATI
Keyword(s):  
Momentum Space ◽  
Planck Scale ◽  
De Sitter ◽  
Curved Spacetime ◽  
Soccer Ball ◽  
The Core ◽  
Core Feature ◽  
Space Curvature ◽  
Curvature Deformation ◽  
Ball Problem

In this paper we construct the action describing dynamics of the particle moving in curved spacetime, with a nontrivial momentum space geometry. Curved momentum space is the core feature of theories where relative locality effects are present. So far aspects of nonlinearities in momentum space have been studied only for flat or constantly expanding (de Sitter) spacetimes, relying on their maximally symmetric nature. The extension of curved momentum space frameworks to arbitrary spacetime geometries could be relevant for the opportunities to test Planck-scale curvature/deformation of particles momentum space. As a first example of this construction we describe the particle with κ-Poincaré momentum space on a circular orbit in Schwarzschild spacetime, where the contributes of momentum space curvature turn out to be negligible. The analysis of this problem relies crucially on the solution of the soccer ball problem.

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