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.

The Strength of Thick-Walled Cylinders

1959 ◽  
Vol 81 (2) ◽  
pp. 95-111 ◽  
Author(s):  
B. Crossland ◽  
S. M. Jorgensen ◽  
J. A. Bones
Keyword(s):  
Shear Stress ◽  
Mild Steel ◽  
Close Agreement ◽  
Large Strain ◽  
Tension Test ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Strain Behavior ◽  
Pressure Tests ◽  
Strain Data

Comprehensive pressure tests have been carried out on thick-walled, closed-ended cylinders made from a mild steel and a hardened and tempered steel, the maximum pressure reached being 94,000 lb/in.2 The complete theoretical behavior of the cylinders is computed from shear stress-strain data obtained from torsion tests and is shown to be in very close agreement with the experimental results. In addition, a method is given for deriving the large strain behavior of the cylinders from tension test data. When compared with the experimental results this approach gives larger errors, the theoretical values of pressure being consistently high. Finally, ultimate pressures have been calculated from two empirical expressions.

scholarly journals Modeling of the torsion test of a cylindrical specimen with the help of the inverse method

2021 ◽  
Vol 266 ◽  
pp. 09003
Author(s):  
D.O. Shishkin ◽  
P.A. Petrov
Keyword(s):  
Rheological Model ◽  
Inverse Method ◽  
Cylindrical Specimen ◽  
Strain Range ◽  
Torsion Test ◽  
Material Model ◽  
Virtual Experiment ◽  
Good Match ◽  
Hardening Curve ◽  
High Degree

This article discusses the torsion problem of a continuous cylindrical specimen used to construct a hardening curve. A brief review of the methods for processing the results of the method of torsion of a cylindrical specimen is given. The possibility of using the inverse method to determine the material model in the case of the torsion of the continuous cylindrical specimen made of steel 20H is shown. By means of QFORM 9.0 software package virtual experiment connected with torsion of a cylindrical specimen is carried out. As a result of this research, the rheological model of steel 20His determined with a high degree of accuracy. The stress-strain state of the material was analyzed during the torsion of the specimen by means of the QFORM. The results of the virtual experiment are compared with the full-scale test.Anexceptionally good match of the results was obtained. The inverse method showed its efficiency and made it possibleto determine a rheological model of the material. The model accurately describes the experimental data. The resulting material model (for steel 20H) is valid in the following range of parameters: deformation temperature of 20°C, deformation rate of 0.5 s−1, the strain range of 0 to 2.5.

Intertester-Reliabilität des Upper Limb Neural Tension Tests (ULNT) 1

2019 ◽  
Vol 23 (02) ◽  
pp. 75-80
Author(s):  
Beate Schüßler ◽  
Andrea Pfingsten ◽  
Thomas Schöttker-Königer
Keyword(s):  
Upper Limb ◽  
Tension Test ◽  
Tension Tests

ZusammenfassungZur Überprüfung der Nervenleitfähigkeit werden Kraft, Reflexe und Sensibilität getestet. Bei der Untersuchung der Mechanosensitivität eines Nervs kommen neurodynamische Tests zum Einsatz. Der Upper Limb Neural Tension Test (ULNT) 1 bestimmt die Mechanosensitivität des N. medianus.Ziel der Studie war die Untersuchung der Intertester-Reliabilität des ULNT 1 von nicht spezialisierten Physiotherapeuten bei Probanden mit unilateralen Nacken- und/oder Armsymptomen.Die Therapeuten beurteilten binär und metrisch die Kriterien patientenspezifische Symptome, strukturelle Differenzierung und Bewegungsausmaß sowie das Gesamtergebnis bei 33 Patienten mit unilateralen Nacken- und/oder Armsymptomen. Bei den binären Daten bestimmte der Fleiss-Kappa und bei den metrischen Daten der Intraklassen-Korrelationskoeffizient die Reliabilität. Die zusätzlich erstellten Regressionsmodelle sollten den Einfluss der einzelnen Beurteilungskriterien auf die Gesamtentscheidung herausfiltern.Mit Ausnahme der Reproduzierbarkeit patientenspezifischer Symptome scheint die Beurteilung des ULNT 1 durch nicht spezialisierte Therapeuten nur schlecht vergleichbar zu sein. Da die metrische Bewertungsweise die individuellen Schwellenwerte besser darstellt, ist diese der binären vorzuziehen.

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.

The stress - strain behaviour of copper over a large strain range

1978 ◽  
Vol 12 (10) ◽  
pp. 903-907 ◽  
Author(s):  
D.J. Lloyd ◽  
D. Kenny
Keyword(s):  
Large Strain ◽  
Strain Range ◽  
Stress Strain ◽  
Strain Behaviour

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.

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