Meso-Macro Scale Behavior Analysis of Polymeric Systems under their Melting States

2008 ◽  
Vol 33-37 ◽  
pp. 1109-1114
Author(s):  
Ying Hao Yu ◽  
Mamtimin Gheni ◽  
Zhong Yuan Lu ◽  
Wei Jiang
Keyword(s):  
Disperse Particle ◽  
Shear Velocity ◽  
Equation Model ◽  
Scale Model ◽  
Scale Analysis ◽  
Polymeric Systems ◽  
Macro Scale ◽  
Computational Fluid Dynamics Cfd ◽  
Scale Behavior ◽  
Meso Scale

In this study, the meso-scale analysis are conducted by using the Disperse Particle Dynamics(DPD) analysis, and the constitutive equation model between viscosity and shear velocity are obtained by using different constrained mutual sufficient area. The macro-scale analysis are conducted by using Finite Element Method(FEM) based on the Computational Fluid Dynamics(CFD). The meso-scale model is smoothly coupled with in macro-scale model by using the relationships between the DPD meso-scale model and the FEM macro-scale model.

scholarly journals Simulation of the forming process for curved composite sandwich panels

2019 ◽  
Vol 13 (6) ◽  
pp. 967-980
Author(s):  
S. Chen ◽  
O. P. L. McGregor ◽  
A. Endruweit ◽  
L. T. Harper ◽  
N. A. Warrior
Keyword(s):  
Sandwich Panels ◽  
High Volume ◽  
Core Structure ◽  
Scale Model ◽  
Axial Deformation ◽  
Forming Process ◽  
The Core ◽  
Macro Scale ◽  
Out Of Plane ◽  
Meso Scale

AbstractFor affordable high-volume manufacture of sandwich panels with complex curvature and varying thickness, fabric skins and a core structure are simultaneously press-formed using a set of matched tools. A finite-element-based process simulation was developed, which takes into account shearing of the reinforcement skins, multi-axial deformation of the core structure, and friction at the interfaces. Meso-scale sandwich models, based on measured properties of the honeycomb cell walls, indicate that panels deform primarily in bending if out-of-plane movement of the core is unconstrained, while local through-thickness crushing of the core is more important in the presence of stronger constraints. As computational costs for meso-scale models are high, a complementary macro-scale model was developed for simulation of larger components. This is based on experimentally determined homogenised properties of the honeycomb core. The macro-scale model was employed to analyse forming of a generic component. Simulations predicted the poor localised conformity of the sandwich to the tool, as observed on a physical component. It was also predicted accurately that fibre shear angles in the skins are below the critical angle for onset of fabric wrinkling.

Application of an EMMS Model for Bubbly Fluidized Bed

2017 ◽  
Vol 372 ◽  
pp. 170-179
Author(s):  
Daniel A. Kestering ◽  
Flavia F.S. Zinani ◽  
George C. Bleyer
Keyword(s):  
Multi Scale ◽  
Macro Scale ◽  
Scale Models ◽  
Fluid Bed ◽  
Computational Fluid Dynamics Cfd ◽  
Geldart Groups ◽  
Coarse Grids ◽  
Individual Particles ◽  
Meso Scale ◽  
Good Agreement

In computational fluid dynamics (CFD) of fluidization processes, the modeling of drag between fluid and particles has a direct effect on the results. The EMMS (Energy Minimization Multi-Scale) models are based on the micro-scale of individual particles and the macro scale of equipment to model the meso-scale phenomena related to particle clustering, which directly affect the drag between fluid and particles. The EMMS/bubbling model was introduced as a change from the classic EMMS model to specific bubbling fluid bed conditions. The present work aims to apply the EMMS/bubbling model in the CFD of Geldart-D particles fluidized by air. The results were compared with results from the literature. It was observed that, for particles of Geldart groups A and B, the results using the EMMS/bubbling model agreed well with the literature. The CFD results for Geldart-D particles showed good agreement with the literature results for this method using coarse grids.

scholarly journals Cyclical changes in deformation process in granular material in active state

2019 ◽  
Vol 92 ◽  
pp. 17004
Author(s):  
Magdalena Pietrzak
Keyword(s):  
Granular Material ◽  
Granular Materials ◽  
Retaining Wall ◽  
Rigid Wall ◽  
Scale Model ◽  
Small Scale ◽  
Macro Scale ◽  
Geotechnical Problem ◽  
Cyclic Changes ◽  
Scale Behavior

This paper presents a detailed study of a selected small scale model test, performed on a sample of surrogate granular material, retained by a rigid wall (typical geotechnical problem of earth thrust on a retaining wall). The experimental data presented in this paper show that the deformation of granular sample behind retaining wall can undergo some cyclic changes. The nature of these cycles is not clear – it is probably related to some micromechanical features of granular materials, which are recently extensively studied in many research centers in the world. Employing very precise DIC (PIV) method can help to relate micro and macro-scale behavior of granular materials.

Variational asymptotic homogenization of beam-like square lattice structures

2019 ◽  
Vol 24 (10) ◽  
pp. 3295-3318 ◽  
Author(s):  
Emilio Barchiesi ◽  
Sergei Khakalo
Keyword(s):  
Timoshenko Beam ◽  
Scaling Laws ◽  
Lattice Structure ◽  
Square Lattice ◽  
Scale Model ◽  
Asymptotic Homogenization ◽  
Macro Scale ◽  
Variational Asymptotic ◽  
Statics And Dynamics ◽  
Meso Scale

By means of variational asymptotic homogenization, using Piola’s meso-macro ansatz, we derive the linear Timoshenko beam as the macro-scale limit of a meso-scale beam-like periodic planar square lattice structure. By considering benchmarks in statics and dynamics, meso-to-macro convergence is numerically analyzed. At the finest micro-scale, a 2D assembly of elastic, geometrically linear, isotropic and homogeneous Cauchy continua in plane strain with different material parameters is considered. Using this description, we calibrate the meso-scale model using standard methodology and, by exploiting the meso-to-macro homogenization scaling laws, we recover bending and shear Timoshenko beam moduli. It turns out that the Timoshenko beam found in this way and the finest-scale description based on the Cauchy continuum are in excellent agreement.

Multi-Scale Investigation on Residual Strength of Jacket Platform With Fatigue Crack Damage

2015 ◽  
Author(s):  
Ren Hua Wang ◽  
Xiang Zou ◽  
Pei Lin Dou ◽  
Yuan Yuan Fang ◽  
Guang-en Luo
Keyword(s):  
Fatigue Crack ◽  
Residual Strength ◽  
Scale Structure ◽  
Scale Model ◽  
Wave Load ◽  
Jacket Platform ◽  
Multi Scale ◽  
Extreme Load ◽  
Macro Scale ◽  
Meso Scale

Fatigue crack damage caused by the wave load brings the structure of jacket platform in service potential failure risk when subjected to the extreme load. However, there is lack of efficient method to evaluate the influence of crack damage on the structural performance because of the huge scale difference between the meso-scale damage and the macro-scale structure. Based on the multi-scale finite element method (FEM), to improve the efficiency of structural analysis, the damaged region of the structure is modeled with fine FE mesh (shell element) to describe the fatigue crack, and the undamaged area is modeled with coarse FE mesh (beam element). Furthermore, the applicability and superiority of this multi-scale model was validated through comparing the results obtained from the beam, multi-scale and shell models. The influence of the time-varying crack damage on the residual strength of jacket platform is then revealed based on the multi-scale FE model. The results show that the proposed multi-scale method can accurately describe fatigue crack damage in the macro-scale structure, and be applied to investigate the influence of meso-scale structural damage under the extreme load condition.

Meso-Scale Experimental & Numerical Studies for Predicting Macro-scale Performance of Advanced Reactive Materials (ARMs)

2015 ◽  
Author(s):  
Naresh Thadhani ◽  
Arun Gokhale ◽  
Jason Quenneville ◽  
Jennifer Breidenich ◽  
Manny Gonzales ◽  
...  
Keyword(s):  
Reactive Materials ◽  
Numerical Studies ◽  
Macro Scale ◽  
Meso Scale

A novel synergistic multi-scale modeling framework to predict micro- and meso-scale damage behaviors of 2D triaxially braided composite

2021 ◽  
pp. 105678952110339
Author(s):  
Hongyong Jiang ◽  
Yiru Ren ◽  
Qiduo Jin
Keyword(s):  
Compressive Load ◽  
Scale Model ◽  
Modeling Framework ◽  
Braided Composite ◽  
Multi Scale ◽  
Scale Modeling ◽  
Bridge Model ◽  
Multi Scale Modeling ◽  
Transverse Damage ◽  
Meso Scale

A novel synergistic multi-scale modeling framework with a coupling of micro- and meso-scale is proposed to predict damage behaviors of 2D-triaxially braided composite (2DTBC). Based on the Bridge model, the internal stress and micro damage of constituent materials are respectively coupled with the stress and damage of tow. The initial effective elastic properties of tow (IEEP) used as the predefined data are estimated by micro-mechanics models. Due to in-situ effects, stress concentration factor (SCF) is considered in the micro matrix, exhibiting progressive damage accumulation. Comparisons of IEEP and strengths between the Bridge and Chamis’ theory are conducted to validate the values of IEEP and SCF. Based on the representative volume element (RVE), the macro properties and damage modes of 2DTBC are predicted to be consistent with available experiments and meso-scale simulation. Both axial and transverse damage mechanisms of 2DTBC under tensile or compressive load are revealed. Micro fiber and matrix damage accumulations have significant effects on the meso-scale axial and transverse damage of tows due to multi-scale coupling effects. Different from existing meso-/multi-scale models, the proposed multi-scale model can capture a crucial phenomenon that the transverse damage of tow is vulnerable to micro fiber fracture. The proposed multi-scale framework provides a robust tool for future systematic studies on constituent materials level to larger-scale aeronautical materials.

scholarly journals A Comparative Evaluation of a Mesoscale Model and Atmospheric Global Circulation Model for Air Quality Simulation: A Multiscale, Multisite Evaluation

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
P. Goswami ◽  
J. Baruah
Keyword(s):  
High Resolution ◽  
Mesoscale Model ◽  
Large City ◽  
Circulation Model ◽  
Urban Pollution ◽  
Atmospheric Pollutants ◽  
Scale Model ◽  
Global Circulation Model ◽  
Global Circulation ◽  
Meso Scale

Concentrations of atmospheric pollutants are strongly influenced by meteorological parameters like rainfall, relative humidity and wind advection. Thus accurate specifications of the meteorological fields, and their effects on pollutants, are critical requirements for successful modelling of air pollution. In terms of their applications, pollutant concentration models can be used in different ways; in one, short term high resolution forecasts are generated to predict and manage urban pollution. Another application of dynamical pollution models is to generate outlook for a given airbasin, such as over a large city. An important question is application-specific model configuration for the meteorological simulations. While a meso-scale model provides a high-resolution configuration, a global model allows better simulation of large-sale fields through its global environment. Our objective is to comparatively evaluate a meso-scale atmospheric model (MM5) and atmospheric global circulation model (AGCM) in simulating different species of pollutants over different airbasins. In this study we consider four locations: ITO (Central Delhi), Sirifort (South Delhi), Bandra (Mumbai) and Karve Road (Pune). The results show that both the model configurations provide comparable skills in simulation of monthly and annual loads, although the skill of the meso-scale model is somewhat higher, especially at shorter time scales.

Sign in / Sign up

Export Citation Format

Share Document