Related Experiment Video
Updated: Feb 25, 2026
13:27
Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface
Published on: June 8, 2015
9.2K
Boundary Layer Effect on Behavior of Discrete Models.
1Brno University of Technology, Faculty of Civil Engineering, Veverˇí 331/95, Brno 60200, Czech Republic. elias.j@fce.vutbr.cz.
Materials (Basel, Switzerland)
|August 5, 2017
Summary
Boundary effects in random rigid body systems alter mechanical properties. Near boundaries, element orientation biases lead to varied stiffness and ductility compared to the bulk material.
Area of Science:
- Physics
- Materials Science
- Mechanical Engineering
Background:
- Discrete models of rigid bodies with random geometry are used to study macroscopic material properties.
- The mechanical behavior of such systems is influenced by the interplay of normal and tangential bonds.
- Directional bias in element orientation can emerge, particularly near boundaries.
Purpose of the Study:
- To investigate the influence of boundary effects on the mechanical properties of randomly generated rigid body systems.
- To analyze how the normal/tangential stiffness ratio affects macroscopic elastic modulus and Poisson's ratio.
- To understand the impact of biased element orientation near boundaries on system stiffness and ductility.
Main Methods:
- Simulating systems of rigid bodies with randomly generated geometry.
- Modeling interconnections using normal and tangential bonds with varying stiffness.
- Analyzing element orientation distributions, especially in boundary layers.
- Comparing simulation results with theoretical predictions.
Main Results:
- Macroscopic elastic modulus is determined by bond stiffness; Poisson's ratio depends on the normal/tangential stiffness ratio.
- Boundary layers exhibit biased element orientation, preferring alignment parallel to the boundary.
- This bias leads to increased stiffness in the boundary layer under certain strain conditions (normal/tangential stiffness ratio > 1).
- Boundary layers become weaker and less ductile due to a higher tendency towards tensile over shear straining.
Conclusions:
- Boundary orientation bias significantly alters local mechanical properties in discrete rigid body systems.
- The normal/tangential stiffness ratio is a critical parameter influencing both bulk and boundary behavior.
- Understanding these boundary effects is crucial for accurate modeling of heterogeneous materials.
Related Concept Videos
01:18Boundary Layer Characteristics
703
When a fluid encounters a solid surface, a boundary layer forms due to the interaction between the fluid's motion and the stationary surface. This phenomenon is characterized by a thin region adjacent to the surface where viscous forces dominate, influencing the fluid's velocity profile. The development of the boundary layer begins at the leading edge of the surface and evolves as the fluid moves downstream.As the fluid flows over the surface, friction between the fluid and the wall slows down...
703
01:15Theories of Dissolution: Diffusion Layer Model
2.0K
Dissolution, the process by which drug particles dissolve in a solvent, is explained by the diffusion layer model, a theoretical framework that simulates the absorption of oral drugs and allows us to analyze experimental data.
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
2.0K
00:57Physiological Pharmacokinetic Models: Blood Flow-Limited Versus Diffusion-Limited Models
394
Physiological pharmacokinetic models, often called flow-limited or perfusion models, typically assume a swift drug distribution between tissue and venous blood, creating a rapid drug equilibrium. This premise is based on the idea that drug diffusion is extremely fast, and the cell membrane presents no barrier to drug permeation. In this scenario, where no drug binding occurs, the drug concentration in the tissue equals that of the venous blood leaving the tissue. This greatly simplifies the...
394
01:09Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model
873
Various dissolution theories provide insight into the factors that influence the dissolution rate. Danckwerts' Model suggests that turbulence, rather than a stagnant layer, characterizes the dissolution medium at the solid-liquid interface. In this model, the agitated solvent contains macroscopic packets that move to the interface via eddy currents, facilitating the absorption and delivery of the drug to the bulk solution. The regular replenishment of solvent packets maintains the...
873
01:13Parameters Affecting Nonlinear Elimination: Zero-Order Input, First-Order Absorption and Two-Compartment Model
374
Drugs administered through various routes can lead to nonlinear elimination, resulting in complex pharmacokinetic behaviors crucial to understanding efficacious drug dosing.
When a drug is administered through a constant intravenous infusion and eliminated via nonlinear pharmacokinetics, it follows zero-order input. For example, oral drugs undergo first-order absorption upon administration and are eliminated through nonlinear pharmacokinetics.
In the case of subcutaneously administered drugs,...
When a drug is administered through a constant intravenous infusion and eliminated via nonlinear pharmacokinetics, it follows zero-order input. For example, oral drugs undergo first-order absorption upon administration and are eliminated through nonlinear pharmacokinetics.
In the case of subcutaneously administered drugs,...
374
01:14Pharmacodynamic Models: Link Model and Systems Pharmacodynamic Model
49
The link model is a fundamental pharmacokinetic-pharmacodynamic (PK–PD) approach to account for delayed drug responses when the observed effect does not immediately correlate with the drug's plasma concentration peak. This delay is mathematically addressed by introducing an effect compartment concentration, Ce, which is kinetically linked to the plasma concentration, Cp, via a first-order rate constant, ke0. The linkage allows for a more accurate prediction of drug effects over time. A...
49