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Showing 1 to 19 of 19 for “"thermal softening"”.
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Analysis of Adiabatic Shear Banding in a Thick-Walled Steel Tube by the Finite Element Method
… as strain hardening, strain-rate hardening and thermal softening. The dynamic loading conditions considered are pure torsion, axial pressure combined with torsion, and internal pressure combined with torsion. Because of the stress concentration, a shear band will first initiate in an element …
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The mechanics of shear-band formation in thermal viscoplastic materials at high rates of loading
… are assumed to exhibit strain rate hardening, thermal softening, and strain hardening or softening. The mechanism leading to shear band formation is assumed to be a thermo-mechanical mechanism.
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Design of Si/SiC hybrid structures for elevated temperature micro-turbomachinery
thermal softening behavior at temperatures above 900 K. This thermal softening behavior limits the turbine inlet temperature, which in turn significantly degrades the overall engine efficiency. Previous studies have shown that hybrid structures of silicon and silicon carbide have good potential for …
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Mode-I Fracture in Bonded Wood: Studies of Adhesive Thermal Stability, and of the Effects of Wood Surface Deactivation
… mode-I fracture testing was used to compare the thermal stability of polyurethane (PUR) and resorcinol-formaldehyde (RF) wood adhesives. Bonded specimens for both adhesives were subjected to prolonged thermal exposure, and fracture testing was subsequently conducted after re-equilibration to …
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Effect of Material and Geometric Parameters on Deformations of a Dynamically loaded Prenotched Plate
… Strain hardening, strain-rate hardening and thermal softening characteristics of the material are modeled by the Johnson-Cook relation. The effect of different material parameters, notch-tip radius, impact speed and the length of the projectile on the maximum tensile principal stress and the …
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Finite element analysis of failure modes in dynamically loaded pre-cracked steel plates
… strain hardening, strain-rate hardening and thermal softening. An approximate solution of the governing equations is sought by using an explicit finite element code DYNA2D. We analyzed the evolution of the shear and hoop stresses considered to be responsible for two modes of failure: opening …
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Wood Material Behavior in Severe Environments
… (EMC) behavior and the moisture dependent softening behavior. EMC data was collected and desorption isotherms were generated for mature and juvenile wood of aspen, loblolly pine and yellow-poplar at 50 and 160°C. High temperature EMC behavior was found to be distinct from that at lower …
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Instabilities in Multiphysics Problems: Micro- and Nano-electromechanical Systems, and Heat-Conducting Thermoelastoviscoplastic Solids
… thermoelastoviscoplastic solid due to thermal softening overcoming hardening caused by strain- and strain-rate effects. Each of these nonlinear multiphysics problems is analyzed by the meshless local Petrov-Galerkin (MLPG) method. The moving least squares (MLS) approximation is used to …
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Silicon carbide process development for microengine applications : residual stress control and microfabrication
… temperatures (1300 to 1700 K). However, the thermal softening of silicon (Si) at temperatures above 900 K limits the highest achievable operating temperatures, which in turn significantly compromises the engine efficiency. Silicon carbide (SiC) offers great potential for improved microengine …
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Continuum and crystal strain gradient plasticity with energetic and dissipative length scales
… mathematically model the small scale materials thermal and mechanical responses by the aid of Materials Science fundamentals, Continuum Solid Mechanics, Misro-scale experimental observations, and Numerical methods. Since conventional continuum plasticity and heat transfer theories, based on the …
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Experimental Quantification of the Phonon Drag Deformation Mechanism in Metals at Extreme Strain Rates
… amount. At these deformation rates, conventional thermal softening effects are now in competition with anti-thermal hardening that arises from ballistic transport of dislocations from phonon interactions in the crystal lattice. These effects are quantified systematically and it is shown that the …
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Analytical modeling and simulation of metal cutting forces for engineering alloys
… have been made to address work hardening and thermal softening effects and allow the material to flow continuously through an opened-up deformation zone. Oxley's analysis of machining is extended to the application of various engineering materials. The basic model is extended to the simulation …
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Finite Element Analysis of Thermoviscoplastic Deformations of an Impact-Loaded Prenotched Plate
… for strain hardening, strain-rate hardening and thermal softening of the material. The material parameters in these relations are found by solving an initial-boundary-value problem corresponding to simple shearing deformations so that the computed effective stress vs. the effective plastic strain …
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Analysis of the Stability and Response of Deep-Seated Landslides by Monitoring their Basal Temperature
… material) is rate (velocity) hardening and thermal softening \cite{Vardoulakis2002}, but this assumption has never been tested experimentally. This model has been applied previously by \cite{Veveakis2007} for the case of the famous Vaiont landslide, which collapsed catastrophically in 1963 …
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Modification of a microbial co-polyester by graft copolymerisation
… company, Bonded Fibre Fabric, namely appropriate thermal characteristics coupled with biodegradability. Microbial polyesters are biodegradable, but no commercial grade was available that met the required thermal criteria detailed below. Therefore it was decided to attempt to lower the thermal …
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Polyphase Proterozoic tectonometamorphic history of the Taos Range, northern New Mexico
… widespread reheating to ~500 degrees Celsius and thermal softening of the middle crust, allowing the crust to flow and deform according to prevailing states of compressional stress. Continued or renewed post-1.4 Ga contractional deformation is indicated by low-temperature microstructures that also …
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Development of a vibration fatigue failure prediction model for automotive lamps made of polymers
… fatigue test machine, this was attributed to thermal softening. A novel test rig for measuring bending fatigue curves of materials based on specimen resonant behaviour was developed and used to experimentally characterise the fatigue data for the PC material. Prior to modelling the dynamic …
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Understanding the Role of Biomass and High Shear Bioreactor Parameters in Bioethanol Production
… barrel temperature facilitates the melting or softening/plasticizing of the feed. Screw speed is responsible for the rate of shear development and the mean residence time of the feed. Moisture content plays a role in thermal softening by utilizing the barrel temperature and rate of shear …
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Proterozoic thermal and deformational history and geochemical evolution of the 1.4 Ga Priest pluton and its aureole
… following pluton emplacement. The well-defined thermal aureole can be used to help constrain both pre- and post-emplacement metamorphisms. Pre-pluton metamorphism is recorded by amphibolite-facies inclusions inside contact metamorphic porphyroblasts. Included minerals are interpreted to be part …