Macro strain-stress determination in a high pressure rotational anvil apparatus

2022 ◽  
Vol 131 (1) ◽  
pp. 015904
Author(s):  
Lin Lin ◽  
Cheng Ji ◽  
Yanzhang Ma
Keyword(s):  
High Pressure ◽  
Stress Determination ◽  
Strain Stress

Propagation of Elasto-Plastic Stress Waves in Cylindrical High-Pressure Sections

1974 ◽  
Vol 96 (3) ◽  
pp. 988-993
Author(s):  
J. R. Baumgarten ◽  
J. R. Dewitt ◽  
A. J. Cable
Keyword(s):  
High Pressure ◽  
Numerical Approach ◽  
Stress Waves ◽  
Thick Wall ◽  
Stress And Strain ◽  
Internal Dynamic ◽  
Dynamic Changes ◽  
Strain Stress ◽  
Physical Laws ◽  
Direct Use

An analysis is made of the axisymmetric elastic and plastic stresses and deformations in thick-wall cylindrical shells subjected to internal dynamic pressures. The study utilizes a direct numerical approach called the discontinuous-step analysis. This analysis is based on the direct use of the boundary conditions and the applicable physical laws to propagate dynamic changes in the cylinder by finite steps. Reflection of stress waves from both inner and outer boundaries is automatically generated. The validity of the method is checked by comparison of numerical results in the elastic range with published results for thick-wall cylinders. Comparison is made with experimentally measured strains from the high-pressure section of a hypervelocity launcher. This analysis assumes that the work hardening of the material is independent of the strain rate and is constant for a large variation of plastic strain. Stress-strain relationships are derived for the condition of plane strain in the cylinder which is held to be representative of the actual conditions in the launcher high-pressure section. The digital computer program developed from this study predicts the distribution of dynamic stress and strain throughout the cylinder, the internal radial growth, the distribution of particle displacement, the distribution of yield stress in an autofrettaged cylinder, and the residual stress.

scholarly journals THERMAL AND STRAIN-STRESS STATE OF HIGH-PRESSURE ROTOR OF K-1000-60/3000 TURBINE OF NPP UNIT

2019 ◽  
Vol 0 (3) ◽  
pp. 132-138
Author(s):  
Olha Yuriivna Chernousenko ◽  
Dmytro Viktorovych Ryndiuk ◽  
Vitalii Anatoliiovych Peshko
Keyword(s):  
High Pressure ◽  
Stress State ◽  
Strain Stress

Spherical harmonics analysis based on the Reuss model in elastic macro strain and stress determination by powder diffraction

2017 ◽  
Vol 50 (6) ◽  
pp. 1735-1743 ◽  
Author(s):  
Nicolae C. Popa
Keyword(s):  
Stress Analysis ◽  
Stress Tensor ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Spherical Harmonics ◽  
Ground State ◽  
Stress Determination ◽  
New Approach ◽  
Generalized Spherical Harmonics ◽  
Strain Stress

In this paper a new approach to macro strain/stress analysis by generalized spherical harmonics is presented. It consists of expanding the stress tensor weighted by texture in a series of generalized spherical harmonics with the ground state of expansion specific to the classical Reuss model of an isotropic polycrystal. Like previously reported models having a ground state of hydrostatic type [Popa & Balzar (2001).J Appl Cryst.34, 187–195] and of Voigt type [Popaet al.(2014).J Appl Cryst.34, 154–159], the actual model is appropriate for use with Rietveld refinement.

Analysis of Strain-Stress of Cubic Hinge Sleeve

2013 ◽  
Vol 313-314 ◽  
pp. 1021-1024 ◽  
Author(s):  
Xuan Sun ◽  
Bin Wang ◽  
Yu Zhang ◽  
Fu Ping Zhou ◽  
Yi Sheng Hu
Keyword(s):  
High Pressure ◽  
Theoretical Basis ◽  
Von Mises Stress ◽  
Realistic Condition ◽  
Reliability Design ◽  
Pressure Load ◽  
Actual Model ◽  
Strain Stress ◽  
Von Mises

Actual model of cubic hinge sleeve was established in Ansys. Strength of cubic hinge sleeve was calculated under high pressure load in realistic condition, which is based on practical processing, results of values of von Mises stress were obtained. It provides a theoretical basis for optimization and reliability design of cubic hinge sleeve.

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

Cryosectioning plant roots prepared by high-pressure freezing

1987 ◽  
Vol 45 ◽  
pp. 662-663
Author(s):  
R.E. Crang ◽  
M. Mueller ◽  
K. Zierold
Keyword(s):  
High Pressure ◽  
Cell Walls ◽  
Plant Tissues ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Vitreous State ◽  
Radial Depth ◽  
Irregular Topography ◽  
Considerable Depth ◽  
Conventional Freezing

Obtaining frozen-hydrated sections of plant tissues for electron microscopy and microanalysis has been considered difficult, if not impossible, due primarily to the considerable depth of effective freezing in the tissues which would be required. The greatest depth of vitreous freezing is generally considered to be only 15-20 μm in animal specimens. Plant cells are often much larger in diameter and, if several cells are required to be intact, ice crystal damage can be expected to be so severe as to prevent successful cryoultramicrotomy. The very nature of cell walls, intercellular air spaces, irregular topography, and large vacuoles often make it impractical to use immersion, metal-mirror, or jet freezing techniques for botanical material.However, it has been proposed that high-pressure freezing (HPF) may offer an alternative to the more conventional freezing techniques, inasmuch as non-cryoprotected specimens may be frozen in a vitreous, or near-vitreous state, to a radial depth of at least 0.5 mm.

High-pressure freezing and freeze substitution of plant tissue

1992 ◽  
Vol 50 (1) ◽  
pp. 748-749
Author(s):  
William P. Sharp ◽  
Robert W. Roberson
Keyword(s):  
High Pressure ◽  
Cell Structure ◽  
Leaf Tissue ◽  
Freeze Substitution ◽  
Crystal Formation ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Components ◽  
Cold Metal ◽  
Brome Grass

The aim of ultrastructural investigation is to analyze cell architecture and relate a functional role(s) to cell components. It is known that aqueous chemical fixation requires seconds to minutes to penetrate and stabilize cell structure which may result in structural artifacts. The use of ultralow temperatures to fix and prepare specimens, however, leads to a much improved preservation of the cell’s living state. A critical limitation of conventional cryofixation methods (i.e., propane-jet freezing, cold-metal slamming, plunge-freezing) is that only a 10 to 40 μm thick surface layer of cells can be frozen without distorting ice crystal formation. This problem can be allayed by freezing samples under about 2100 bar of hydrostatic pressure which suppresses the formation of ice nuclei and their rate of growth. Thus, 0.6 mm thick samples with a total volume of 1 mm3 can be frozen without ice crystal damage. The purpose of this study is to describe the cellular details and identify potential artifacts in root tissue of barley (Hordeum vulgari L.) and leaf tissue of brome grass (Bromus mollis L.) fixed and prepared by high-pressure freezing (HPF) and freeze substitution (FS) techniques.

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