• Multiscale and Multiphysics Mechanics
• /
• v.1 no.1
• /
• pp.65-76
• /
• 2016

In this study, an influence of local variation of nanoparticulate volume fraction on the homogenized elastic properties is investigated. It is well known that interface effect is dependent on the radius and volume fraction of reinforced nanofillers. However, there is no study on the multiscale modeling and analysis of polymer nanocomposites including polydispersed nanoparticles with consideration of interphase zone, which is dependent on the volume fraction of corresponding nanoparticles. As results of numerical examples, it is confirmed that an influence of local variation of nanoparticulate volume fraction should be considered for non-dilute system such as cluster of nanoparticles. Therefore representative volume element analysis is conducted by considering local variation of nanoparticle volume fraction in order to analyze the practical size of cell including hundreds of nanoparticles. It is expected that this study could be extended to the multiparticulate nanocomposite systems including polydispersed nanoparticles.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.04a
• /
• pp.125-129
• /
• 2005

A micromechanical model for predicting the elastic constants of stitched multi-axial warp knitted (MWK) composite is developed. The averaging method is used to obtain effective properties of stitched MWK fabric composites. In the analysis, a representative volume of the MWK fabric composite is identified. The geometric limitations, effects of stitching yarns and design parameters of MWK fabric composites are considered in the model. Then, the elastic properties of stitched MWK fabric composites are predicted. Finally, the predicted elastic constants are validated by comparison with experimental data. The predicted results are in fair agreement with the experimental results.

• Computers and Concrete
• /
• v.5 no.3
• /
• pp.175-194
• /
• 2008

Increasingly numerical (finite element) modeling of concrete hinges on our ability to develop a representative volume element with all its heterogeneity properly discretized. Yet, despite all the sophistication of the ensuing numerical models, the initial discretization has been for the most part simplistic. Whenever the heterogeneity of the concrete is to be accounted for, a mesh is often manually crafted through the arbitrary inclusion of the particles (aggregates and/or voids) in an ad-hoc manner. This paper develops a mathematical strategy to precisely address this limitation. Algorithms for the random generation and placement of elliptical (2D) or ellipsoid (3D) inclusions, with possibly radiating cracks, in a virtual concrete model are presented. Collision detection algorithms are extensively used.

• Journal of Powder Materials
• /
• v.24 no.1
• /
• pp.17-23
• /
• 2017

In this study, a finite element analysis approach is proposed to predict the fluid-structure interaction behavior of active materials for lithium-ion batteries (LIBs), which are mainly composed of graphite powder. The porous matrix of graphite powder saturated with fluid electrolyte is considered a representative volume element (RVE) model. Three different RVE models are proposed to consider the uncertainty of the powder shape and the porosity. P-wave modulus from RVE solutions are analyzed based on the microstructure and the interaction between the fluid and the graphite powder matrix. From the results, it is found that the large surface area of the active material results in low mechanical properties of LIB, which leads to poor structural durability when subjected to dynamic loads. The results obtained in this study provide useful information for predicting the mechanical safety of a battery pack.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.78-81
• /
• 2002

Printed Circuit Boards for satellite are composed of multi-layered copper plate and glass epoxy. Each copper layer have the complicated and different pattern to operate correctly for its mission. Especially. copper layer give effect on the PCB stiffness seriously. But It can make more complicate to predict the exact stiffness of PCB. In KOMPSAT-2 program, too many type of PCB are used for each electronic unit, and they have different type of pattern of copper layer. Solar array regulator has two type of PCB and it will be considered for this study. In this study. we calculate the PCB board stiffness of KOMPSAT-2 SAR unit considering the concept of simplified representative volume element. It will be correlated with the test results under KOMPSAT-2 vibration environmental condition to increase the reliability of this study.

• Journal of Mechanical Science and Technology
• /
• v.20 no.10
• /
• pp.1722-1729
• /
• 2006

Predicting the mechanical properties of the 3-D scaffold using finite element method (FEM) simulation is important to the practical application of tissue engineering. However, the porous structure of the scaffold complicates computer simulations, and calculating scaffold models at the pore level is time-consuming. In some cases, the demands of the procedure are too high for a computer to run the standard code. To address this problem, the representative volume element (RVE) theory was introduced, but studies on RVE modeling applied to the 3-D scaffold model have not been focused. In this paper, we propose an improved FEM-based RVE modeling strategy to better predict the mechanical properties of the scaffold prior to fabrication. To improve the precision of RVE modeling, we evaluated various RVE models of newly designed 3-D scaffolds using FEM simulation. The scaffolds were then constructed using microstereolithography technology, and their mechanical properties were measured for comparison.

• Transactions of Materials Processing
• /
• v.24 no.3
• /
• pp.194-198
• /
• 2015

Microstructure based FE simulations were conducted to investigate the micro-mechanical properties of ferrite-martensite dual-phase steels. The FE model was built based on real microstructure images which were characterized by optical microscopy through the thickness direction. Serial sectioned 2D images were converted into semi-2D representative volume elements (RVEs) model. Each RVE model was subjected to a non-proportional loading condition and the mechanical response was analyzed on both the macroscopic and microscopic levels. Macroscopically, stress-strain curves were described under tension-compression and tension-orthogonal tension conditions and the Bauschinger effect was well captured for both loading paths. In addition, micromechanical properties were investigated in the view of stress-strain partitioning and strain localization during monotonic tension.

• Structural Engineering and Mechanics
• /
• v.77 no.5
• /
• pp.651-659
• /
• 2021

In this study, a new constitutive model has been developed to predict the elastic behavior of plain weave textile composites, using the finite element (FE) method. The geometric conditions and basic assumptions of this model are based on the basics of a continuum theory developed for the plane curved composites. In this model, the mechanical properties of the weave region and pure matrix region is calculated separately and then imported for the FE analysis. This new constitutive model is used to implement the mechanical properties of weave region in the representative volume element (RVE). The constitutive relations are implemented as user-material subroutine code (UMAT) in ABAQUS® FE software. The results of FE analysis have been compared with experimental results and other data available in the literature. These comparisons confirmed the capability of the presented model for the prediction of effective elastic properties of plain weave fabric composites.

• Structural Engineering and Mechanics
• /
• v.90 no.4
• /
• pp.403-415
• /
• 2024

We looked at how the damping qualities of epoxy composites changed when different amounts of graphite nanoplatelets (GNP) were added, from 0% to 6% by weight. A mix of free and forced vibration tests helped us find the key GNP content that makes the damper ability better the most. We also created a Representative Volume Element (RVE) model to guess how the alloys would behave mechanically and checked these models against testing data. An Artificial Neural Network (ANN) was also used to guess how these compounds would react to motion. With proper hyperparameter tweaking, the ANN model showed good correlation (R²=0.98) with actual data, indicating its ability to predict complex material behavior. Combining these methods shows how GNPs impact epoxy composite mechanical properties and how machine learning might improve material design. We show how adding GNPs to epoxy composites may considerably reduce vibration. These materials may be used in industries that value vibration damping.

• 한국석유지질학회:학술대회논문집
• /
• autumn
• /
• pp.42-42
• /
• 2000