scholarly journals Analytical and DEM studies of thermal stress in granular materials

2021 ◽  
Vol 249 ◽  
pp. 14018
Author(s):  
Tokio Morimoto ◽  
Catherine O’Sullivan ◽  
David M. G. Taborda
Keyword(s):  
Granular Materials ◽  
Thermal Loading ◽  
Practical Importance ◽  
Analytical Formula ◽  
Random Packing ◽  
Complementary Series ◽  
Dem Simulations ◽  
Induced Stress ◽  
Stress Changes ◽  
Random Packings

The ability to predict thermal-induced stresses in granular materials is of practical importance across a range of disciplines ranging from process engineering to geotechnical engineering. This study presents an analytical formula to predict thermal-induced stress increments in mono-disperse granular materials subject to an initial isotropic stress state. A complementary series of DEM simulations were carried out to explore the applicability of the proposed analytical formula. The comparative analysis showed that the proposed expression can accurately predict stress changes in packings where there are negligible particle displacements as a consequence of the thermal loading (e.g. regular packings and medium/dense random packings); however large errors were observed in loose samples with a random packing.

scholarly journals Penetration strength of coarse granular materials from DEM simulations

2013 ◽  
Author(s):  
Juan Carlos Quezada ◽  
Gilles Saussine ◽  
Pierre Breul ◽  
Farhang Radjai
Keyword(s):  
Granular Materials ◽  
Dem Simulations

Influence of a Variable in Time Heat Transfer Coefficient on Stresses in Model of Power Plant Components

2013 ◽  
Author(s):  
Jerzy Okrajni ◽  
Mariusz Twardawa
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Mechanical Behaviour ◽  
Power Plants ◽  
Thermal Loading ◽  
Computer Modelling ◽  
Temperature Fields ◽  
Fluid Medium ◽  
Stress Changes ◽  
Plant Components

The paper discusses the issue of modelling of strains and stresses resulting from heating and cooling processes of components in power plants. The main purpose of the work is to determine the mechanical behaviour of power plant components operating under mechanical and thermal loading. Finite element method (FEM) has been used to evaluate the temperature and stresses changes in components as a function of time. Temperature fields in the components of power plants are dependent, among parameters, on variable heat-transfer conditions between components and the fluid medium, which may change its condition, flowing inside them. For this reason, evaluation of the temperature field and the consequent stress fields requires the use of heat-transfer coefficients as time-dependent variables and techniques for determining appropriate values for these coefficients should be used. The methodology of combining computer modelling of the temperature fields with its measurements performed at selected points of the pipelines may be used in this case. The graphs of stress changes as a function of time have been determined for the chosen plant components. The influence of the heat transfer conditions on the temperature fields and mechanical behaviour of components have been discussed.

The Effective Thermal Conductivity of a Packing of Spheres

1990 ◽  
Vol 57 (3) ◽  
pp. 789-791 ◽  
Author(s):  
A. Jagota ◽  
C. Y. Hui
Keyword(s):  
Thermal Conductivity ◽  
Temperature Field ◽  
Closed Form ◽  
Effective Thermal Conductivity ◽  
Granular Materials ◽  
Upper Bound ◽  
Random Packing ◽  
Fabric Tensor ◽  
Mean Temperature

The anisotropic effective thermal conductivity of a random packing of spheres is derived. The conductivity is closely related to the fabric tensor of the theory of granular materials. The derivation involves a mean temperature field assumption which is shown to render the model an upper bound. Closed-form expressions for the conductivity are obtained in the isotropic and axisymmetric cases.

A note on induced stress changes in hydrocarbon and geothermal reservoirs

1998 ◽  
Vol 289 (1-3) ◽  
pp. 117-128 ◽  
Author(s):  
Paul Segall ◽  
Shaun D. Fitzgerald
Keyword(s):  
Geothermal Reservoirs ◽  
Induced Stress ◽  
Stress Changes

scholarly journals A constitutive model with microstructure evolution for flow of rate-independent granular materials

2011 ◽  
Vol 682 ◽  
pp. 590-616 ◽  
Author(s):  
JIN SUN ◽  
SANKARAN SUNDARESAN
Keyword(s):  
Friction Coefficient ◽  
Constitutive Model ◽  
Granular Materials ◽  
Simple Shear ◽  
Evolution Equations ◽  
Complex Loading ◽  
Dem Simulations ◽  
Particle Level ◽  
Complex Rheology ◽  
Using Data

A constitutive model is developed for the complex rheology of rate-independent granular materials. The closures for the pressure and the macroscopic friction coefficient are linked to microstructure through evolution equations for coordination number and fabric. The material constants in the model are functions of particle-level properties and are calibrated using data generated through simulations of steady and unsteady simple shear using the discrete element method (DEM). This model is verified against DEM simulations at complex loading conditions.

Origin of MeV ion irradiation-induced stress changes in SiO2

2000 ◽  
Vol 88 (1) ◽  
pp. 59-64 ◽  
Author(s):  
M. L. Brongersma ◽  
E. Snoeks ◽  
T. van Dillen ◽  
A. Polman
Keyword(s):  
Ion Irradiation ◽  
Induced Stress ◽  
Stress Changes

scholarly journals Predator-induced stress changes parental feeding behavior in pied flycatchers

2010 ◽  
Vol 22 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Vallo Tilgar ◽  
Kadri Moks ◽  
Pauli Saag
Keyword(s):  
Feeding Behavior ◽  
Induced Stress ◽  
Parental Feeding ◽  
Stress Changes
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