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Showing 1 to 20 of 69 for “"High strain rates"”.
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Dynamic Shear Bands in Metals under High Strain Rates
… applications. Analysis of these localizations highly depends on the selection of the constitutive model. Hence, two 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, …
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Fault formation in porous sedimentary rocks at high strain rates
… faults 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 …
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On the Characterization of Engineered Elastomers At High Strain Rates
… and modelling 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 …
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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
… increasing use in structures subjected to high rate loading such as blast or impact. Proper design of such structures requires thorough characterisation of the material behaviour over a range of loading rates from quasi-static to impact. This thesis investigated the quasi-static and impact …
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Development and proving of a split Hopkinson pressure bar used for high strain rate materials testing
… is necessary to determine material properties at high strain rates. Conventional screw-driven or servo-hydraulic methods of testing materials at high strain rates are not adequate as oscillations and stress waves are set-up within the testing apparatus. These oscillations and stress waves foul the …
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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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Pressure-impulse diagrams using finite element analysis for reinforced concrete columns subjected to blast loading
… of three material models of LS-DYNA subjected to high strain rates is studied. The effects of strain rate and lateral inertial confinement on the strength enhancement are investigated. Recommendations are made to improve the accuracy of the results of future numerical simulations for reinforced …
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Modeling dynamic impact of layered structures
… advances have allowed for the use of high-powered lasers to create strain rates above 10^7 1/s. However, experimental data of impact tests at these ultra-high rates is still sparse, so the behavior of materials at these high strain rates is not well-understood. The goal of this study …
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Shear-based Deformation Processing and Characterization of Electrical Steel Sheet
… into sheet is demonstrated by application of highly confined shear deformation in the form of metal cutting. Iron-silicon (Fe-Si) alloys, of major interest to electromagnetic applications, are characterized by poor workability. Through the interactive combination of simple shear, high strain …
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The effect of alloy chemistry and strain rate on the Md30 temperature of metastable austenitic stainless steels
… objectives, uniaxial tensile tests at 0.3 true strain were performed at low and high strain rates (10-3s-1 and 3 x 10-2s-1 respectively), in the temperature range of -60 to 55°C under isothermal testing conditions.
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High strain rate properties of structural aluminium.
… been used in the past to determine the stress-strain relationship of metals and alloys at high strain rates of up to 2.2 x 10 per second; some of these were approximate whilst others required expensive equipment. In the present study three aluminium alloys, HE15, HE30TF and DTD5044 have been …
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Rate Effects in Fine Grained Soils
The strain rate dependent behaviour of fine grained soils is an important aspect of geotechnical engineering. During dynamic or rapid events such as earthquakes and rapid pile testing, a fine grained soil will display significantly different behaviour than may be observed over the long life span of …
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Molecular tailoring of interfaces for thin film on substrate systems
… polyimide films on passivated silicon substrates, self-assembled monolayers at the interface of Au films and dielectric substrates, and mechanochemically active materials on rigid substrates. For all three materials systems, the effect of interfacial modifications on adhesion is assessed …
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Implementation of viscoelastic Hopkinson bars
The properties of soft, viscoelastic materials at high strain rates are important in furthering our understanding of their role during blast or impact events. Testing these soft or low impedance materials using metallic bars in a split Hopkinson pressure bar setup, poor signal to noise ratios and …
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Characterization of UHMWPE Laminates for High Strain Rate Applications
… effort to characterize the properties of ultra-high molecular weight polyethylene (UHMWPE). As a composite of polymers, the properties of UHMWPE are time-dependent. It is desired by research sponsors to know the properties of the material at high strain rates, in order to simulate the use of …
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Mechanisches Verhalten metallischer Werkstoffe über weite Bereiche der Dehnung, der Dehnrate und der Temperatur
… conditions was analysed at quasi-static strain rates up to high dynamic loading at temperatures from RT up to 400°C for the aluminium alloy respectively 800°C for the steel. For the examination of the mechanical behaviour compression tests have been conducted on cylindrical and …
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Micromechanics of deformation in polymers modified by inorganic and rubber particles
… brittle behavior at low temperatures and/or high strain rates. It has been shown that the incorporation of rubber and inorganic particles can have significant toughening effects. Previous studies have shown that the particles can alter the matrix morphology at the particle-polymer interface …
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ULTRA-HIGH STRAIN RATE CONSTITUTIVE MODELING OF PURE TITANIUM USING PARTICLE IMPACT TEST
… to study materials mechanics under extremely high deformation rates, i.e., above 10^6 s^-1, a relatively less explored regime of strain rates. In this study, we accelerate microparticles of commercially pure titanium to ~100 m/s towards a rigid substrate and record their deformation upon …
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Tools for the formation of optimised X-80 steel blast tolerant transverse bulkheads
… material constants for X-80 steel under high strain rates were obtained. These material constants were implemented in the finite element analysis and the appropriate solid element size was evolved. The behaviour and effects of stress waves and high strain rates were considered and the …
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