Compressive strength of iceberg ice

2003 ◽  
Vol 81 (1-2) ◽  
pp. 191-200 ◽  
Author(s):  
S J Jones ◽  
R E Gagnon ◽  
A Derradji ◽  
A Bugden
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Strain Rate ◽  
Strain Rate Range ◽  
Air Bubbles ◽  
Strain Rates ◽  
Thin Sections ◽  
Rate Range ◽  
A Value ◽  
Wide Range

The uniaxial compressive strength of iceberg ice was determined over a wide range of strain rates from 10–8 to 10+1 s–1 at –10°C. It was found that for strain rates less than 10–4 s–1, strength increased in a power-law manner with strain rate. Above 10–4 s–1, the strength was essentially constant at 4 MPa, dropping slightly between 10–3 and 10–1 s–1, before rising again to a value of about 10 MPa at 10+1 s–1. Thin sections of the ice revealed a small grain size of about 3.5 mm and elongated air bubbles with a ratio of length to width of about 10. In the practical strain-rate range of interest, the maximum failure stress observed was 4.8 MPa. PACS No.: 62.20

DYNAMIC TENSILE PROPERTIES OF IRON AND STEELS FOR A WIDE RANGE OF STRAIN RATES AND STRAIN

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1255-1262 ◽  
Author(s):  
NOBUSATO KOJIMA ◽  
HIROYUKI HAYASHI ◽  
TERUMI YAMAMOTO ◽  
KOJI MIMURA ◽  
SHINJI TANIMURA
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Large Strain ◽  
Strain Rate Range ◽  
Block Type ◽  
Strain Rates ◽  
Viscous Term ◽  
Rate Range ◽  
Wide Range ◽  
True Fracture

The tensile stress-strain curves of iron and a variety of steels, covering a wide range of strength level, over a wide strain rate range on the order of 10−3 ~ 103 s −1, were obtained systematically by using the Sensing Block Type High Speed Material Testing System (SBTS, Saginomiya). Through intensive analysis of these results, the strain rate sensitivity of the flow stress for the large strain region, including the viscous term at high strain rates, the true fracture strength and the true fracture strain were cleared for the material group of the ferrous metals. These systematical data may be useful to develop a practical constitutive model for computer codes, including a fracture criterion for simulations of the dynamic behavior in crash worthiness studies and of work-pieces subjected to dynamic plastic working for a wide strain rate range.

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.

Tensile Stress-Strain Curves Modeling of Four Kinds of Solders with Temperature and Rate Dependence

2005 ◽  
Vol 297-300 ◽  
pp. 905-911 ◽  
Author(s):  
Xu Chen ◽  
Li Zhang ◽  
Masao Sakane ◽  
Haruo Nose
Keyword(s):  
Tensile Stress ◽  
Constitutive Model ◽  
Strain Rate ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Rate Dependence ◽  
Strain Rates ◽  
Stress Strain ◽  
Rate Range

A series of tensile tests at constant strain rate were conducted on tin-lead based solders with different Sn content under wide ranges of temperatures and strain rates. It was shown that the stress-strain relationships had strong temperature- and strain rate- dependence. The parameters of Anand model for four solders were determined. The four solders were 60Sn-40Pb, 40Sn-60Pb, 10Sn-90Pb and 5Sn-95Pb. Anand constitutive model was employed to simulate the stress-strain behaviors of the solders for the temperature range from 313K to 398K and the strain rate range from 0.001%sP -1 P to 2%sP -1 P. The results showed that Anand model can adequately predict the rate- and temperature- related constitutive behaviors at all test temperatures and strain rates.

scholarly journals Effect of Strain Rate on Compressive Behavior of a Zr-Based Metallic Glass under a Wide Range of Strain Rates

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2861
Author(s):  
Wenqing Li ◽  
Tieqiang Geng ◽  
Shaofan Ge ◽  
Zhengwang Zhu ◽  
Long Zhang ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
Yield Strength ◽  
Strain Rate ◽  
Amorphous Alloys ◽  
High Strain ◽  
Strain Rate Range ◽  
Strain Rate Effect ◽  
Strain Rates ◽  
Compressive Behavior ◽  
Rate Range

The strain rate effect on the mechanical behavior of amorphous alloys has aroused general interest. Most studies in this area have focused on quasi-static and high strain-rate compressive deformations. However, experimental results have been few, or even non-existent, under a moderate strain-rate loading. This article extends the traditional split Hopkinson pressure bar (SHPB) technique to characterize compressive deformation of an amorphous alloy at medium strain rates. The compressive behavior of Zr65.25Cu21.75Al8Ni4Nb1 amorphous alloy shows a negative strain rate effect on the yield strength with a quasi-static, moderate to high strain-rate range, and the fracture angle increases from 44° at 10−5 s−1 to 60° at 4000 s−1 as strain rate increases. Herein, we introduce a modified cooperative shear model to describe the compressive behavior of the current amorphous alloy under a broad strain rate range. The model predicts that the normalized yield strength will linearly descend with logarithmic strain rate when the strain rate is less than a critical strain rate, however, which rapidly decreases linearly with the square of the strain rate at high strain rates. The predicted data of the model are highly consistent with the current experimental results. These findings provide support for future engineering applications of amorphous alloys.

scholarly journals A Modified Eyring Equation for Modeling Yield and Flow Stresses of Metals at Strain Rates Ranging from 10−5to 5 × 104 s−1

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Ramzi Othman
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Large Strain ◽  
Rate Sensitivity ◽  
Industrial Applications ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Wide Range ◽  
Large Strain Rate

In several industrial applications, metallic structures are facing impact loads. Therefore, there is an important need for developing constitutive equations which take into account the strain rate sensitivity of their mechanical properties. The Johnson-Cook equation was widely used to model the strain rate sensitivity of metals. However, it implies that the yield and flow stresses are linearly increasing in terms of the logarithm of strain rate. This is only true up to a threshold strain rate. In this work, a three-constant constitutive equation, assuming an apparent activation volume which decreases as the strain rate increases, is applied here for some metals. It is shown that this equation fits well the experimental yield and flow stresses for a very wide range of strain rates, including quasi-static, high, and very high strain rates (from 10−5to 5 × 104 s−1). This is the first time that a constitutive equation is showed to be able to fit the yield stress over a so large strain rate range while using only three material constants.

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 10−7 to 10−1s−1, grain–size ranged from 1.5 to 5.8 mm, and the test temperature was −5°C.At strain-rates between 10−7 and 10−3 s−1, the stress-strain-rate relationship followed a power law with an exponent of n = 4.3 calculated without regard to grain-size. However, a reversal in the grain-size effect was observed: below a transition point near 4 × 10−6 s−1 the 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 10−3 s−1 the 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.

Rate-Dependent Behavior and Constitutive Model of Polycarbonate at Strain Rate from 10-5 to 103 S-1

2011 ◽  
Vol 117-119 ◽  
pp. 434-437
Author(s):  
Wen Jun Hu ◽  
Xi Cheng Huang ◽  
Fang Ju Zhang ◽  
Cheng Jun Chen
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Temperature Dependent ◽  
Static Tests ◽  
Rate Range ◽  
Rate Dependent ◽  
Dependent Behavior

Uni-axial quasi-static tests at strain rates 10-5, 10-4, 10-3,10-2 and 10-1 s-1 and dynamic compressive tests at strain rates 1679, 2769,5000 and 8200 s-1 have been carried out to study the mechanical behavior for polycarbonate used in the avigation industry. The stress–strain curves of polycarbonate in the strain-rate range from 10-5 to 8200 s-1 have been obtained. The effects of the strain rate on yield phenomenon and rate-dependent mechanical behavior are discussed. A plastic flow law based on the DSGZ rate-temperature-dependent constitutive model was used to describe the mechanical behavior of polycarbonate in the strain-rate range from 10-5 to 103 s-1. The results at the six strain rates are in excellent agreement with the experimental data, which illustrates that the constitutive model can describe the mechanical behavior for polycarbonate at low and high strain rates perfectly.

scholarly journals Modification of Charpy machine for the acquisition of stress-strain curve in thermoplastics

DYNA ◽  
2020 ◽  
Vol 87 (213) ◽  
pp. 52-60
Author(s):  
Luis Miguel Zabala Gualtero ◽  
Ulises Figueroa López ◽  
Andrea Guevara Morales ◽  
Alejandro Rojo Valerio
Keyword(s):  
Strain Rate ◽  
Strain Curve ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Static Tests ◽  
Wide Range ◽  
Plastic Components ◽  
Impact Simulations

Simulations of impact events in the automotive industry are now common practice. Vehicle crashworthiness simulations on plastic components cover a wide range of strain rates from 0.01 to 500 s-1. Because plastics mechanical properties are very dependent on strain rate, developing experimental methods for generating stress-strain curves at this strain rate range is of great technological importance. In this paper, a modified Charpy machine capable of acquiring useful information to obtain the stress-strain curve is presented. Strain rates between 300 to 400 s-1 were achieved. Three thermoplastics were tested: high-density polyethylene, polypropylene-copolymer and polypropylene-homopolymer. Impact simulations using LS-DYNA were performed using the acquired high-strain rates stress-strain curves and compared with experimental data. Simulations using stress-strain curves from quasi-static tests were also performed for comparison. Very good agreement between the simulation and experimental results was found when the ASTM D1822 type S specimen was used for testing each material.

Deformation Mechanisms in Ultrafine-Grained Zn at Different Strain Rates and Temperatures

2013 ◽  
Vol 592-593 ◽  
pp. 313-316
Author(s):  
Péter Jenei ◽  
Guy Dirras ◽  
Jenő Gubicza ◽  
Hervé Couque
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Strain Rate Range ◽  
Deformation Mechanisms ◽  
Coarse Grained ◽  
Strain Rates ◽  
Initial State ◽  
Rate Range ◽  
Hexagonal Close Packed ◽  
Ultrafine Grained

The deformation mechanisms in ultrafine-grained hexagonal close packed Zn were investigated at different strain rates and temperatures. The influence of grain size on the deformation mechanisms was revealed by comparing the results obtained on ultrafine-grained and coarse-grained Zn. It was found that for coarse-grained Zn at room temperature and strain rates lower than 10-2s-1twinning contributed to plasticity besides dislocation activity. For strain rates higher than 103s-1the plasticity in coarse-grained Zn was controlled by dislocation drag. In ultrafine-grained Zn the relatively large dislocation density (~1014m-2) and the small grain size (~250 nm) limit the dislocation velocity yielding the lack of dislocation drag effects up to 104s-1. For ultrafine-grained Zn, twinning was not observed in the entire strain rate range due to its very small grain size. During room temperature compression at strain rates higher than 0.35 s-1and in high temperature creep deformation of ultrafine-grained Zn besides prismatic and pyramidal <c+a> dislocations observed in the initial state, <a>-type basal and pyramidal dislocations as well as other <c+a>-type pyramidal dislocations were formed.

scholarly journals The Confined Compressive Strength of Polycrystalline Ice

1982 ◽  
Vol 28 (98) ◽  
pp. 171-178 ◽  
Author(s):  
Stephen J. Jones
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Strain Rates ◽  
Maximum Compressive Stress ◽  
A Value ◽  
Polycrystalline Ice ◽  
Confining Pressures ◽  
Unconfined Strength

AbstractTriaxial tests were carried out on randomly oriented, laboratory-made, polycrystalline ice, between strain-rates of 10–7 and 10–1 s–1 and with confining pressures from 0.1 to 85 MN m–2, at –11 ± 1°C. Below strain-rates of about 10–5 s–1 the confining pressure has little effect, but at higher strain-rates the confining pressure prevents cracking which allows the compressive strength to rise to a value greater than the unconfined compressive strength. At 1.4 ×10–2 s–1, the unconfined strength of 12 MN m–2 rises to 26 MN m–2 with a confining pressure of 25 MN m–2, before dropping slowly with greater confining pressures. Above 10–2 s–1 the unconfined strength decreases rapidly with increasing strain-rate, but the confined strength continues to increase. The dependence of strain rate on the maximum compressive stress is discussed.

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