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Showing 1 to 20 of 289 for “"strain rates"”.
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Dynamic Shear Bands in Metals under High Strain Rates
… constitutive models that take temperature and strain rate effect into account are proposed. The first model is a physically based model that depends on basic physical quantities, such as dislocation densities, Burgers vector, and activation energy. The second model is a simple empirical power …
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Fault formation in porous sedimentary rocks at high strain rates
… in porous sedimentary rocks subjected to high strain rates do not form from deformation band damage zones (DBDZs) as typically observed in porous rocks. This hypothesis is evaluated by an investigation of faults mapped within the porous Navajo Sandstone at the Upheaval Dome impact structure in …
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On the Characterization of Engineered Elastomers At High Strain Rates
… of elastomers that were subject to high-strain rate. Four aspects of the problem were accordingly examined. The first aspect of the study was dedicated to the comparison of constitutive equations to numerically model elastomers. The second aspect revolved around the testing of elastomers …
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Experimental determination of strain rates in stretched laminar diffusion flames
… were made at four different operating flow rates, and were used to compute the associated strain rate fields. The results were used to qualitatively assess current CFDF modeling schemes, and to expand the knowledge of the fluid velocity field behavior within these flames. The data show …
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Finite strain behavior of polyurea for a wide range of strain rates
… as its high toughness-to-density ratio and high strain rate-sensitivity, so its application is recently extended to structural purpose to form sandwich-type or multi-layered plates. Those structures can be used for retrofitting of military vehicles and historic buildings, absorbing energy during …
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Extraction of mechanical properties over a range of strain rates from indentation data
… to study a rigidly held target, with operative strain rates of the order 105 s-1. Input for the FEM model includes data characterizing the (temperature-dependent) quasi-static plasticity, obtained by conventional uniaxial testing. The experimental outcomes are displacement-time plots for the …
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Determination of material properties of mild steel at different temperatures and strain rates
… yield stress of mild steel with temperature and strain rate. This was achieved by carrying out high temperature tensile tests at different strain rates on mild steel specimens. These experiments also helped set a methodology for carrying out high temperature tensile tests using a servohydraulic …
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Experimental determination of material properties for materials subjected to high compressive strain rates
… for materials subjected to high compressive strain rates using the split Hopkinson bar is discussed along with the assumptions made and their meanings. Some preliminary results for a lucite material are used to illustrate the type of information obtained from using the method. Limitations of …
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Experimental Quantification of the Phonon Drag Deformation Mechanism in Metals at Extreme Strain Rates
Extreme strain rate deformations, above 10⁶ s⁻¹, are seen across many fields of science and engineering; from meteorite impacts and impact induced crystallographic phase changes to high-speed machining and additive manufacturing. Despite the range of applications, many common high-rate impact …
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Extending the annular in-plane torsional shear test specimen to applications at high strain rates
… to generate instabilities, thus large true strains up to 1 can be achieved. Before this research, the specimen had only been used for material characterisation in the quasi-static regime. The aim of this research was to conduct further quasi-static testing using the in-plane torsion test and …
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Characterisation of Glass Fibre Polypropylene and GFPP based Fibre Metal Laminates at high strain rates
… the material behaviour over a range of loading rates from quasi-static to impact. This thesis investigated the quasi-static and impact response of Glass Fibre Polypropylene (GFPP) in compression, bending and delamination. The bending and delamination response of Fibre Metal Laminates (FMLs) …
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Experimental Techniques for Shear Testing of Thin Sheet Metals and Compression Testing at Intermediate Strain Rates
… various directions. Tests are conducted at shear strain rates ranging from 0.01(1/s) to 9000(1/s). Traditionally, shear characterization is performed through torsion tests on thin walled tube specimens, which are impossible to fabricate from thin sheet metals. The proposed specimen geometry is …
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FAILURE MECHANISMS OF ULTRA HIGH MOLAR MASS POLYETHYLENE SINGLE FIBERS AT EXTREME TEMPERATURES AND STRAIN-RATES
The effects of temperature and strain-rate on the mechanical properties of Ultra High Molar Mass Polyethylene (UHMMPE) single fibers was investigated at eleven temperatures from room temperature (20 °C) to the orthorhombic-hexagonal phase transition (148 °C) and at six strain-rates from …
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Extinction strain rates of n-butanol, 2-butanol and iso-butanol in counterflow non-premixed flamelets
The extinction strain rates of three butanol isomers, (n-butanol, sec-butanol and iso-butanol) were studied experimentally in a counterflow burner, and computationally using a one-dimensional numerical model. The experimental results provided an insight in how the difference between molecular …
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Computational modeling of the impact response of Roma Plastilina across a wide range of strain rates
… the mechanical response across the range of strain rates of interest. To address this deficiency, the previous model formulation is extended to a more general rate-dependence model of the power-law type. Three impact tests are used to calibrate the modified constitutive model for the clay: …
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Effect of strain rates on tensile properties and fracture toughness determination of extruded Mg-Al-Zn alloys
… tensile properties, tensile properties at high strain rates of extruded magnesium alloys and their fracture behaviour are some of the important parameters to be considered in design in ensuring the durability and reliability of automobile structures. In this study, the effect of strain rates on …
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An Investigation of the Mechanical Properties of Aircraft Engine Fan Casing Abradable Materials at Different Temperatures and Strain Rates
… temperatures (tension and compression), and high strain-rate (tension and compression) conditions. Despite compositional differences, both studied materials exhibited unequal resistance to tensile and compressive loading (compression strength higher than tensile), as well as significant …
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Stress-strain properties and micro-structural change in metal deformed at strain rates of upto 10^5 per second.
… Comparative studies showed that copper was more strain ratesensitive than aluminium and steel used in the present investigation.There were no marked differences observed in the microstructures of the structural steel specimen deformed quasi-statically and dynamically at -30°C, room …
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Effect of nano-fibers on the stress-strain behavior of semi-crystalline poly(ethylene terephthalate) at different strain rates
… various amounts of nano-fibers added. The stress-strain behavior for each material at several strain rates is presented. A typical stress-strain curve consists of a relatively steep rise in stress at small strains where the slope is the Young's Modulus. Then, the stress reaches a maximum before …
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