A novel temperature-dependent yield stress model for ceramic materials under indentation

2020 ◽  
Vol 46 (7) ◽  
pp. 9943-9946
Author(s):  
Chaojuan Li ◽  
Ruzhuan Wang ◽  
Xiaorong Wang ◽  
Dingyu Li ◽  
Weiguo Li
Keyword(s):  
Yield Stress ◽  
Ceramic Materials ◽  
Stress Model ◽  
Temperature Dependent

scholarly journals Yield Stress Model for Natural Debris Flows in Presence of Fine and Coarse–Grained Sediments

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1865
Author(s):  
Leonardo Schippa
Keyword(s):  
Yield Stress ◽  
Debris Flows ◽  
Rheological Behaviour ◽  
Coarse Fraction ◽  
Coarse Grained ◽  
Stress Model ◽  
Coarse Sediment ◽  
Fine Grain ◽  
Sediment Fraction ◽  
Coarse To Fine

When dealing with natural geo–hazards, it is important to understand the influence of sediment sorting on debris flows. The presence of coarse fraction is one of the aspects which affects the rheological behaviour of natural viscous granular fluid mixtures. In this paper, experiments on reconstituted debris flow mixtures with different coarse–to–fine sediment ratios are considered. Such mixtures behave just as non–Newtonian yield stress fluids and their rheological behaviour is largely affected by the presence of coarse fraction. Experimental results demonstrate that yield stress is very sensitive not only to bulk sediment concentration but also to coarse sediment fraction. A novel yield stress model is presented. It accounts for an empirical grading function depending on the coarse–to–fine grain content. The yield stress model performed satisfactorily in comparison with the experiments, showing that it is almost independent of the coarse–to–fine grain fraction in case of dominant coarse sediment content.

scholarly journals Molten composition B-3 yield stress model

2018 ◽  
Author(s):  
S. M. Davis ◽  
D. K. Zerkle ◽  
L. B. Smilowitz ◽  
B. F. Henson
Keyword(s):  
Yield Stress ◽  
Stress Model

Temperature-dependent evolution of the cyclic yield stress of railway wheel steels

Wear ◽  
2016 ◽  
Vol 366-367 ◽  
pp. 378-382 ◽  
Author(s):  
Johan Ahlström ◽  
Elena Kabo ◽  
Anders Ekberg
Keyword(s):  
Yield Stress ◽  
Temperature Dependent ◽  
Railway Wheel ◽  
Railway Wheel Steels

Temperature Dependence of the Yield Stress in α-Titanium Investigated with Crystal Plasticity Analysis

2018 ◽  
Vol 941 ◽  
pp. 1474-1478
Author(s):  
Yelm Okuyama ◽  
Masaki Tanaka ◽  
Tetsuya Ohashi ◽  
Tatsuya Morikawa
Keyword(s):  
Finite Element ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Crystal Plasticity ◽  
Slip Systems ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Pyramidal Slip ◽  
Active Slip ◽  
Lattice Friction

The effect of the activated slip systems on the temperature dependence of yield stress was investigated in α-Ti by using crystal plasticity finite element method. A model for finite element analysis (FEA) was constructed based on experimental results. The displacement in FEA was applied up to the nominal strain of 4% which is the same strain as the experimental one. Stress-strain curves were obtained, which corresponds to experimental data taken every 50 K between 73 K and 673 K. The used material constants which are temperature dependent were elastic constants, and lattice friction stresses. The lattice friction stresses of basal slip systems were set to be higher than that of pyramidal slip systems at 73 K. Then, the lattice friction stresses were set to be closer as the temperature increases. It was found that the activation of slip systems is strong temperature dependent, and that the yield stress depends on the number of active slip systems.

Overview of Proposed High Temperature Design Code Cases

2016 ◽  
Author(s):  
Peter Carter ◽  
T.-L. (Sam) Sham ◽  
Robert I. Jetter
Keyword(s):  
High Temperature ◽  
Yield Stress ◽  
Creep Damage ◽  
Cyclic Strain ◽  
Inelastic Strain ◽  
Cyclic Creep ◽  
Strain Accumulation ◽  
Temperature Dependent ◽  
Common Basis ◽  
Creep Fatigue

Proposals for high temperature design methods have been developed for primary loads, creep-fatigue and strain limits. The methodologies rely on a common basis and assumption, that elastic, perfectly plastic analysis based on appropriate properties reflects the ability of loads and stress to redistribute for steady and cyclic loading for high temperature as well as for conventional design. The cyclic load design analyses rely on a further key property, that a cyclic elastic-plastic solution provides an upper bound to displacements, strains and local damage rates. The primary load analysis ensures that the design load is in equilibrium with the code allowable stress, taking into account: i) The stress state dependent (multi-axial) rupture criterion, ii) The limit to stress re-distribution defined by the material creep law. The creep-fatigue analysis is focused on the cyclic creep damage calculation, and uses conventional fatigue and creep-fatigue damage calculations. It uses a temperature-dependent pseudo “yield” stress defined by the material yield and rupture data to identify cycles which will not cause creep damage > 1 for the selected life. Similarly the strain limits analysis bounds cyclic strain accumulation. It also uses a temperature-dependent pseudo “yield” stress defined by the material yield and creep strain accumulation data to identify cycles which will not cause average (membrane) inelastic strain > 1% for the design life. The paper gives an overview of the background and justification of these statements, and examples.

Behavior of a Compressible Magnetorheological Fluid Damper at High Temperatures

2011 ◽  
Author(s):  
Micheal McKee ◽  
Xiaojie Wang ◽  
Faramarz Gordaninejad
Keyword(s):  
Theoretical Model ◽  
Bulk Modulus ◽  
Yield Stress ◽  
Magnetorheological Fluid ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Bingham Plastic ◽  
Shear Yield ◽  
Fluid Dampers ◽  
Temperature Dependent Properties

This study focuses on the effect of temperature on the performance of compressible magnetorheological fluid dampers (CMRDs). In addition to change of properties in the presence of a magnetic field, magnetorheological fluids (MRFs) are temperature-dependent materials that their compressibility and rheological properties change with temperature, as well. A theoretical model that incorporates the temperature-dependent properties of MRF is developed to predict the behavior of a CMRD. An experimental study is also conducted using an annular flow CMRD with varying temperatures, motion frequencies, and magnetic fields. The experimental results are used to verify the theoretical model. The effect of temperature on the MRF properties, such as, the bulk modulus, yield stress and viscosity, are explored. It is found that the shear yield stress of the MRF remains unchanged within the testing range while both the plastic viscosity, using the Bingham plastic model, and the bulk modulus of the MRF decrease as temperature increases. In addition, it is observed that both the stiffness and the energy dissipation decrease with an increase in temperature.

Dynamics of cooling domes of viscoplastic fluid

2000 ◽  
Vol 422 ◽  
pp. 225-248 ◽  
Author(s):  
N. J. BALMFORTH ◽  
R. V. CRASTER
Keyword(s):  
Thin Layer ◽  
Yield Stress ◽  
Stability Theory ◽  
Constitutive Relations ◽  
Linear Stability Theory ◽  
Viscoplastic Fluid ◽  
Surface Cooling ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity

A non-isothermal viscoplastic thin-layer theory is developed to explore the effects of surface cooling, yield stress, and shear thinning on the evolution of non-isothermal domes of lava and laboratory fluids. The fluid is modelled using the Herschel–Bulkley constitutive relations, but modified to have temperature-dependent viscosity and yield stress. The thin-layer equations are solved numerically to furnish models of expanding, axisymmetrical domes. Linear stability theory reveals the possibility of non-axisymmetrical, fingering-like instability in these domes. Finally, the relevance to lava and experiments is discussed.

scholarly journals The Research of Magneto-Rheological Fluid Yield Stress Model

OALib ◽  
2018 ◽  
Vol 05 (06) ◽  
pp. 1-7
Author(s):  
Meng Ji ◽  
Yiping Luo
Keyword(s):  
Yield Stress ◽  
Stress Model ◽  
Magneto Rheological
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