An Expression of Plastic Anisotropy in Large Strain Range

2003 ◽  
Vol 233-236 ◽  
pp. 95-100
Author(s):  
Manabu Gotoh
Keyword(s):  
Large Strain ◽  
Plastic Anisotropy ◽  
Strain Range

Development of Cyclic Triaxial Apparatus with Broad Frequency and Strain Ranges

1996 ◽  
Vol 1548 (1) ◽  
pp. 1-8 ◽  
Author(s):  
W. B. Gookin ◽  
M. F. Riemer ◽  
R. W. Boulanger ◽  
J. D. Bray
Keyword(s):  
Soil Properties ◽  
Large Strain ◽  
Strain Range ◽  
Small Strain ◽  
Internal Displacement ◽  
Testing System ◽  
Single Specimen ◽  
Bender Elements ◽  
Measurement Devices ◽  
Displacement Measurements

A cyclic triaxial testing system capable of measuring very small to large strain properties on a single specimen has been developed by combining a wide variety of existing instrumentation, including piezoceramic bender elements, internal displacement measurement devices (both contact and noncontact), local displacement measurement devices, a sensitive internal load cell, and an external load cell. The bender elements provide information on soil properties in the nearly linear elastic (very small strain) range. Local and noncontact internal displacement measurements provide information about small strain range properties, whereas more traditional internal displacement measurements provide information in the small to large strain range. In addition, this apparatus can be used over a wide range of loading frequencies to investigate the effect of frequency on dynamic soil properties. By combining this equipment in a single testing system, a number of tests may be run on one specimen, eliminating the effects of variability. The broad variety of displacement measuring instruments also allows direct comparisons of these techniques on a single specimen.

Experimental extrapolation of hardening curve for cylindrical specimens via pre-torsion tension tests

2019 ◽  
Vol 55 (1-2) ◽  
pp. 20-30
Author(s):  
Junfu Chen ◽  
Zhiping Guan ◽  
Pinkui Ma ◽  
Zhigang Li ◽  
Dan Gao
Keyword(s):  
Inverse Method ◽  
Lower Cost ◽  
Large Strain ◽  
Strain Range ◽  
Tension Test ◽  
Calculation Methods ◽  
Reasonable Accuracy ◽  
Tension Tests ◽  
Strain Data ◽  
Hardening Curve

The hardening curve for cylindrical specimens determined by conventional uniaxial tension tests generally corresponds to a relatively narrow strain range due to the occurrence of necking. To achieve the hardening curve within a large strain range, in this study, the multi-specimen tension tests with pre-torsion are developed through extrapolating the hardening curve from the stress–strain data of cylindrical specimens with various magnitudes of pre-torsion strains. The calculation of pre-strain of twisted specimen needs to be addressed for the multi-specimen tension tests. The three calculation methods on the multi-specimen tension tests are proposed, leading to their individual hardening curves for Q345 specimens. An optimal strategy for the multi-specimen tests with pre-torsion is presented by comparison with the inverse method for a single specimen tension test. The results for Q345 specimen show the strain range (0–0.6) of the hardening curve determined by the multi-specimen tension tests is significantly larger than one (0–0.04) from conventional tension test, with reasonable accuracy. Compared with the current multi-specimen tests with pre-extrusion/drawing, the proposed multi-specimen tests with pre-torsion is possessed of stronger applicability and generality, lower cost, and higher efficiency.

Development of Material Constants for Nonlinear Finite-Element Analysis

1988 ◽  
Vol 61 (5) ◽  
pp. 879-891 ◽  
Author(s):  
Robert H. Finney ◽  
Alok Kumar
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Large Strain ◽  
Strain Range ◽  
Nonlinear Finite Element ◽  
Element Analysis ◽  
Material Models ◽  
Tensile Data

Abstract The determination of the material coefficients for Ogden, Mooney-Rivlin, Peng, and Peng-Landel material models using simple ASTM D 412 tensile data is shown to be a manageable task. The application of the various material models are shown to be subject to the type and level of deformation expected, with Ogden showing the best correlation with experimental data over a large strain range for the three types of strain investigated. At low strains, all of the models showed reasonable correlation.

Dynamic Behavior of Rubber During Moderate Extensions

1966 ◽  
Vol 39 (2) ◽  
pp. 328-339
Author(s):  
A. Schallamach ◽  
D. B. Sellen ◽  
H. W. Greensmith
Keyword(s):  
Natural Rubber ◽  
Large Strain ◽  
Strain Range ◽  
Time Function ◽  
Time Dependent ◽  
Energy Losses ◽  
Simple Extension ◽  
Butadiene Rubber ◽  
Mooney Equation ◽  
Strain Function

Abstract The stresses and energy losses during simple extension cycles to about 130 per cent maximum elongation have been determined for unfilled vulcanizates of natural rubber and acrylontrile-butadiene rubber at various rates of extension and temperatures. The results obey the Ferry transform, with the exception of natural rubber at the larger strains near the high temperature end of the experimental range. The stress-strain curves at increasing strain cannot be described as the product of one strain function and one time function, but the two-term Mooney equation with time dependent coefficients represents the results over a large strain range. Maxima in the strain-increasing stress curves have been observed which are not connected with necking. A suggestion is made as to why the negative slopes in these curves need not necessarily lead to instability.

scholarly journals Creep and plasticity of glacier ice: a material science perspective

2010 ◽  
Vol 56 (200) ◽  
pp. 1059-1068 ◽  
Author(s):  
Paul Duval ◽  
Maurine Montagnat ◽  
Fanny Grennerat ◽  
Jerome Weiss ◽  
Jacques Meyssonnier ◽  
...  
Keyword(s):  
Long Range ◽  
Materials Science ◽  
Large Strain ◽  
Plastic Anisotropy ◽  
Ice Cores ◽  
Model Material ◽  
Experimental Investigations ◽  
Range Interaction ◽  
Full Field ◽  
Long Range Correlations

AbstractMajor advances in understanding the plasticity of ice have been made during the past 60 years with the development of studies of the flow of glaciers and, recently, with the analysis of deep ice cores in Antarctica and Greenland. Recent experimental investigations clearly show that the plastic deformation of the ice single crystal and polycrystal is produced by intermittent dislocation bursts triggered by long-range interaction of dislocations. Such dislocation avalanches are associated with the formation of dislocation patterns in the form of slip lines and slip bands, which exhibit long-range correlations and scale invariance. Long-range dislocation interactions appear to play an essential role in primary creep of polycrystals and dynamic recrystallization. The large plastic anisotropy of the ice crystal is at the origin of large strain and stress heterogeneities within grains. The use of full- field approaches is now a compulsory proceeding to model the intracrystalline heterogeneities that develop in polycrystals. Ice is now highly regarded among the materials science community. It is considered a model material for understanding deformation processes of crystalline materials and polycrystal modeling.

Direct-Write Stretchable Sensors Using Single-Walled Carbon Nanotube/Polymer Matrix

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Morteza Vatani ◽  
Yanfeng Lu ◽  
Kye-Shin Lee ◽  
Ho-Chan Kim ◽  
Jae-Won Choi
Keyword(s):  
Large Strain ◽  
Strain Range ◽  
Free Form ◽  
Gauge Factor ◽  
Direct Write ◽  
Wearable Electronics ◽  
Resistance Change ◽  
Single Walled Carbon ◽  
3D Structural Electronics ◽  
Stretchable Sensors

There have been increasing demands and interests in stretchable sensors with the development of flexible or stretchable conductive materials. These sensors can be used for detecting large strain, 3D deformation, and a free-form shape. In this work, a stretchable conductive sensor has been developed using single-walled carbon nanotubes (SWCNTs) and monofunctional acrylate monomers (cyclic trimethylolpropane formal acrylate and acrylate ester). The suggested sensors have been fabricated using a screw-driven microdispensing direct-write (DW) technology. To demonstrate the capabilities of the DW system, effects of dispensing parameters such as the feed rate and material flow rate on created line widths were investigated. Finally, a stretchable conductive sensor was fabricated using proper dispensing parameters, and an experiment for stretchability and resistance change was accomplished. The result showed that the sensor had a large strain range up to 90% with a linear resistance change and gauge factor ∼2.7. Based on the results, it is expected that the suggested DW stretchable sensor can be used in many application areas such as wearable electronics, tactile sensors, 3D structural electronics, etc.

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