scholarly journals The elastic modulus of columnar-grain fresh-water ice

1994 ◽  
Vol 19 ◽  
pp. 13-18 ◽  
Author(s):  
Lorne W. Gold
Keyword(s):  
Grain Size ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Temperature Dependence ◽  
Fresh Water ◽  
Compressive Loading ◽  
Stress And Strain ◽  
Strain Rates ◽  
Water Ice ◽  
Columnar Grain

An analysis is presented of stress and strain measurements made during an investigation of the characteristics of cracks formed in columnar-grain, type S2 fresh-water ice, during uniaxial, compressive loading at the nominal strain rates of 10−3, 10−4 and 10−5s−1, and temperatures of −5°, −10°, −20° and −30°C. The analysis shows that for this range of strain rate and temperature, ice behaves as an anelastic solid. Results are given for the time, grain-size and temperature dependence of the elastic modulus in the plane perpendicular to the long direction of the grains. They are shown to be in reasonable agreement with results of an earlier study of the anelastic behaviour of the same type of ice. It is suggested that the grain-size and temperature dependence of the elastic moduli of ice for this range of strain rate and temperature may be due, in part, to the dependence of the relaxation time on these variables.

scholarly journals The elastic modulus of columnar-grain fresh-water ice

1994 ◽  
Vol 19 ◽  
pp. 13-18 ◽  
Author(s):  
Lorne W. Gold
Keyword(s):  
Grain Size ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Temperature Dependence ◽  
Fresh Water ◽  
Compressive Loading ◽  
Stress And Strain ◽  
Strain Rates ◽  
Water Ice ◽  
Columnar Grain

An analysis is presented of stress and strain measurements made during an investigation of the characteristics of cracks formed in columnar-grain, type S2 fresh-water ice, during uniaxial, compressive loading at the nominal strain rates of 10−3, 10−4 and 10−5s−1, and temperatures of −5°, −10°, −20° and −30°C. The analysis shows that for this range of strain rate and temperature, ice behaves as an anelastic solid. Results are given for the time, grain-size and temperature dependence of the elastic modulus in the plane perpendicular to the long direction of the grains. They are shown to be in reasonable agreement with results of an earlier study of the anelastic behaviour of the same type of ice. It is suggested that the grain-size and temperature dependence of the elastic moduli of ice for this range of strain rate and temperature may be due, in part, to the dependence of the relaxation time on these variables.

scholarly journals Strain-Rate and Grain‒Size Effects in Ice

1987 ◽  
Vol 33 (115) ◽  
pp. 274-280 ◽  
Author(s):  
David M. Cole
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Transition Point ◽  
Boundary Migration ◽  
Peak Stress ◽  
Strain Rates ◽  
Thin Sections ◽  
Fine Grained ◽  
Lower Strain ◽  
Polycrystalline Ice

AbstractThis paper presents and discusses the results of constant deformation-rate tests on laboratory-prepared polycrystalline ice. Strain-rates ranged from 10−7to 10−1s−1, grain–size ranged from 1.5 to 5.8 mm, and the test temperature was −5°C.At strain-rates between 10−7and 10−3s−1, the stress-strain-rate relationship followed a power law with an exponent ofn= 4.3 calculated without regard to grain-size. However, a reversal in the grain-size effect was observed: below a transition point near 4 × 10−6s−1the peak stress increased with increasing grain-size, while above the transition point the peak stress decreased with increasing grain-size. This latter trend persisted to the highest strain-rates observed. At strain-rates above 10−3s−1the peak stress became independent of strain-rate.The unusual trends exhibited at the lower strain-rates are attributed to the influence of the grain-size on the balance of the operative deformation mechanisms. Dynamic recrystallization appears to intervene in the case of the finer-grained material and serves to lower the peak stress. At comparable strain-rates, however, the large-grained material still experiences internal micro-fracturing, and thin sections reveal extensive deformation in the grain-boundary regions that is quite unlike the appearance of the strain-induced boundary migration characteristic of the fine-grained material.

Research on Numerical Algorithm of Constitutive Equation under High Speed Deformation in Hadfield Steel

2012 ◽  
Vol 562-564 ◽  
pp. 688-692 ◽  
Author(s):  
Deng Yue Sun ◽  
Jing Li ◽  
Fu Cheng Zhang ◽  
Feng Chao Liu ◽  
Ming Zhang
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Speed ◽  
High Strain ◽  
Equivalent Stress ◽  
Hadfield Steel ◽  
Stress And Strain ◽  
Strain Rates ◽  
The Finite Element Method

The influence of the strain rate on the plastic deformation of the metals was significant during the high strain rate of loading. However, it was very difficult to obtain high strain rate data (≥ 104 s-1) by experimental techniques. Therefore, the finite element method and iterative method were employed in this study. Numerical simulation was used to characterise the deformation behavior of Hadfield steel during explosion treatment. Base on experimental data, a modified Johnson-Cook equation for Hadfield steel under various strain rate was fitted. The development of two field variables was quantified during explosion hardening: equivalent stress and strain rates.

scholarly journals Statistical characteristics for the type and length of deformation-induced cracks in columnar-grain ice

1997 ◽  
Vol 43 (144) ◽  
pp. 311-320 ◽  
Author(s):  
Lorne W. Gold
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Strain Rate ◽  
Relative Proportion ◽  
Constant Strain Rate ◽  
Statistical Characteristics ◽  
Columnar Grain ◽  
Log Normal ◽  
Almost All ◽  
Log Normal Distribution

AbstractObservations are reported on cracks formed during compressive, unidirectional, constant-strain-rate deformation of columnar-grain ice. The axis of hexagonal crystallographic symmetry of each grain tended to be in the plane perpendicular to the long direction of the grains and to have a random orientation in that plane. For stress applied perpendicular to the long direction of the grains, the deformation was practically two-dimensional. It was found that the relative proportion of grain-boundary cracks increased with increasing strain rate, decreasing temperature and, for strain rate greater than 7 × 10−5 s−1, with decreasing grain-size. Almost all the grain-boundary cracks had at least one edge at a triple point. For each test, the grain-boundary and transcrystalline crack lengths tended to have a log-normal distribution. The logarithmic mean crack length (LMCL) decreased with increasing strain rate, decreasing grain-size and decreasing temperature and tended to a constant value of 0.75 mm at 10°C. For grain-size of 3 mm or greater, the LMCL had a maximum at a strain rate of 10−5 to 10−6 S−1 at −10°C. The LMCLs and the relative proportion of grain-boundary cracks tended to be normally distributed for given load conditions.

High Strain Rate Blow Formability of Newly Developed Al-Mg-High-Mn Alloy

2012 ◽  
Vol 735 ◽  
pp. 271-277 ◽  
Author(s):  
Tomoyuki Kudo ◽  
Akira Goto ◽  
Kazuya Saito
Keyword(s):  
Grain Size ◽  
High Strain Rate ◽  
Strain Rate ◽  
Mass Production ◽  
High Strain ◽  
Mg Alloy ◽  
Strain Rates ◽  
Fine Grain ◽  
Aa5083 Alloy ◽  
Complex Parts

Blow forming accompanied with superplasticity makes possible the forming of complex parts, which cannot be formed by cold press forming. The conventional superplastic AA5083 alloy ‘ALNOVI-1’ developed by the Furukawa-Sky Aluminum Corp. shows high superplasticity because of its fine grain and is widely used for blow forming. However, for mass production of components, an Al-Mg alloy with finer-sized grains is needed. In this research, the newly developed high Mn version of the Al-Mg alloy ‘ALNOVI-U’ is used, and this material possesses grains finer than those of the conventional AA5083 alloy. The effects of finer grain size on the blow formability at high strain rates over 10-2/s and the properties of the resulting moldings were studied.

scholarly journals Effects of Crystal Orientation and Grain Boundary Inclination on Stress Distribution in Bicrystal Interface of Austenite Stainless Steel 316L

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Fu-qiang Yang ◽  
He Xue ◽  
Ling-yan Zhao ◽  
Xiu-Rong Fang ◽  
Hai-bing Zhang
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Elastic Modulus ◽  
Grain Boundary ◽  
Single Crystals ◽  
Crystal Orientation ◽  
Stress And Strain ◽  
Face Centered Cubic ◽  
Stainless Steel 316L ◽  
Load Direction

Nuclear structural material austenitic stainless steel 316L is a polycrystalline composed of single crystals with a face-centered cubic (FCC) structure, and the intergranular stress corrosion cracking (IGSCC) is closely related to the crystal orientation. A constitutive model is presented to assess the elastic response of anisotropic behavior of single crystals in 316L in this study. With a bicrystal model built by the finite element method, the effects of crystal orientation and grain boundary (GB) inclination on the stress state nearby a symmetric tilt GB were discussed under the constant-displacement condition. The results indicate that when tensile axes are perpendicular to the GB, the stress and strain are equal at the GB and inside the grain, and the crystal misorientation has little effects on the stress and strain distribution. If the GB is not perpendicular to the load direction, the GB inclination angle will change the equivalent elastic modulus along the load direction and result in a larger stress in the grain with larger equivalent elastic modulus, but the stress tends to be equal inside the two grains. The grain size effects verification shows that the conclusions are independent of grain size.

Coupling effect of strain rate and temperature on tensile damage mechanism of polyphenylene sulfide reinforced by glass fiber (PPS/GF30)

2020 ◽  
pp. 089270572094422
Author(s):  
Mohammadali Shirinbayan ◽  
Joseph Fitoussi ◽  
Farid Kheradmand ◽  
Arash Montazeri ◽  
Peiyuan Zuo ◽  
...  
Keyword(s):  
Strain Rate ◽  
Glass Fiber ◽  
High Strain ◽  
Coupling Effect ◽  
Damage Mechanism ◽  
Tensile Tests ◽  
Ultimate Stress ◽  
Polyphenylene Sulfide ◽  
Stress And Strain ◽  
Strain Rates

Influence of loading temperature on the damage mechanism of polyphenylene sulfide (PPS) reinforced by glass fiber (PPS/GF30) under tension was experimentally studied from quasi-static (QS) to high strain rates. Two kinds of PPS/GF30 samples were prepared: PPS-0° and PPS-90° (correspond to fibers oriented parallel and perpendicular to the injection direction, respectively). After microscopic observation and thermomechanical characterizations by dynamic mechanical analysis, tensile tests up to failure with strain rates varying from 10−3 s−1 to 100 s−1 have been carried out at 25°C and 120°C with regard to PPS/GF30 glass transition temperature. To achieve the coupling effect of high strain rate and high temperature, a special chamber was designed to install on the servo-hydraulic machine. The results of QS tensile tests confirm the significant effect of fiber orientation and temperature on the Young’s modulus, the ultimate stress, and strain. High strain tensile test results showed that the PPS/GF30 composite is strain rate dependent at both temperatures. The results indicated that Young’s modulus remains constant by strain rate increasing at both temperatures while ultimate stress and strain are increased. No significant damage has been observed at 25°C in QS loading, whereas the macroscopic damage variable is increased to 20% at 120°C. Debonding at the fiber–matrix interface is the main damage mechanism at 120°C.

scholarly journals An Image-Based Impact Test for the High Strain Rate Tensile Properties of Brittle Materials

2018 ◽  
Vol 183 ◽  
pp. 02042
Author(s):  
Lloyd Fletcher ◽  
Fabrice Pierron
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
High Strain Rate ◽  
Strain Rate ◽  
Stress Wave ◽  
High Strain ◽  
Brittle Materials ◽  
Test Method ◽  
Strain Rates ◽  
High Strain Rates

Testing ceramics at high strain rates presents many experimental diffsiculties due to the brittle nature of the material being tested. When using a split Hopkinson pressure bar (SHPB) for high strain rate testing, adequate time is required for stress wave effects to dampen out. For brittle materials, with small strains to failure, it is difficult to satisfy this constraint. Because of this limitation, there are minimal data (if any) available on the stiffness and tensile strength of ceramics at high strain rates. Recently, a new image-based inertial impact (IBII) test method has shown promise for analysing the high strain rate behaviour of brittle materials. This test method uses a reflected compressive stress wave to generate tensile stress and failure in an impacted specimen. Throughout the propagation of the stress wave, full-field displacement measurements are taken, from which strain and acceleration fields are derived. The acceleration fields are then used to reconstruct stress information and identify the material properties. The aim of this study is to apply the IBII test methodology to analyse the stiffness and strength of ceramics at high strain rates. The results show that it is possible to identify the elastic modulus and tensile strength of tungsten carbide at strain rates on the order of 1000 s-1. For a tungsten carbide with 13% cobalt binder the elastic modulus was identified as 516 GPa and the strength was 1400 MPa. Future applications concern boron carbide and sapphire, for which limited data exist in high rate tension.

Time and Temperature Dependence of the Ultimate Properties of an SBR Rubber at Constant Elongations

1961 ◽  
Vol 34 (3) ◽  
pp. 897-909
Author(s):  
Thor L. Smith ◽  
Paul J. Stedry
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Temperature Dependence ◽  
Rate Dependence ◽  
Strain Rates ◽  
Type Specimens ◽  
Stress Strain ◽  
Ultimate Elongation ◽  
Tensile Tester ◽  
Ultimate Properties

Abstract A study was made previously of the temperature and strain rate dependence of the stress at break (tensile strength) and the ultimate elongation of an unfilled SBR rubber. In that study, stress-strain curves to the point of rupture were measured with an Instron tensile tester on ring type specimens at 14 temperatures between −67.8° and 93.3° C, and at 11 strain rates between 0.158×10−3 and 0.158 sec−1 at most temperatures. The tensile strength was found to increase with both increasing strain rate and decreasing temperature. At all temperatures above −34.4° C, the ultimate elongation was likewise found to increase with increasing strain rate and decreasing temperature but at lower temperatures the opposite dependence on rate was observed; at −34.4° C, the ultimate elongation passed through a maximum with increasing rate.

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