Computational modeling of self-assembly in deformable bodies

Bilgin, Koçak
Self-assembly is a process in which an irregular system transforms into a regular pattern or an organized structure through local interactions between the components of the material without any external influence. Therefore, self-assembly has great potential in the synthesis and manufacture of new materials. Although the main focus in the literature is mostly on self-assembly at the molecular level, there are many exciting applications of the self-assembling processes at larger scales. Space and time-varying patterns are described by various classes of spatio-temporal partial differential equations. The reaction-transport problems constitute one of these classes that employs the Cahn-Hilliard-type equation, also originally a fourth-order transport equation, for patterning. This study is concerned with the effect of mechanical stresses on the generated pattern in a self-assembling process. For mechanics, both finite elasticity and viscoelasticity are considered. To this end, the Cahn-Hilliard equations are solved together with the conservation equation of the linear momentum. The finite element method is used to solve the coupled partial differential equations. It is anticipated that the coupling with mechanics will open up possibilities for the design of new materials and lead to novel experiments for various kinds of self-assembly. Numerous representative numerical examples are presented to illustrate the characteristics and physics of the coupled and decoupled phase separation and self-assembly problems.


IDER, YZ; Gençer, Nevzat Güneri; ATALAR, E; TOSUN, H (1990-03-01)
An algorithm is developed for electrical impedance tomography (EIT) of finite cylinders with general cross-sectional boundaries and translationally uniform conductivity distributions. The electrodes for data collection are assumed to be placed around a crosssectional plane; therefore the axial variation of the boundary conditions and also the potential field are expanded in Fourier series. For each Fourier component a two-dimensional (2-D) partial differential equation is derived. Thus the 3-D forward probl...
Fast and accurate analysis of three-dimensional structures involving near-zero-index materials
Karaosmanoglu, Bariscan; Koyaz, Yesim; İbili, Hande; Ergül, Özgür Salih (2019-09-01)
We present efficient and accurate frequency-domain analysis of three-dimensional structures involving near-zero-index (NZI) materials with very small permittivity and/or permeability values. Accurate simulations are required to analyze these homogenized models that represent metamaterials with exotic NZI properties, which can be useful in a plethora of applications. When traditional solution methods are directly applied, however, instability and inaccuracy issues arise, making solutions inefficient and inac...
Modeling of the nonlinear behavior of steel framed structures with semi rigid connections
Sarıtaş, Afşin; Özel, Halil Fırat (null; 2015-07-21)
A mixed formulation frame finite element with internal semi-rigid connections is presented for the nonlinear analysis of steel structures. Proposed element provides accurate responses for spread of inelasticity along element length by monitoring the nonlinear responses of several crosssections, where spread of inelasticity over each section is captured with fiber discretization. Each material point on the section considers inelastic coupling between normal stress and shear stress. The formulation of the ele...
Numerical Analysis of Viscoelastic Fluids in Steady Pressure-Driven Channel Flow
YAPICI, KERİM; Karasözen, Bülent; Uludağ, Yusuf (2012-05-01)
The developing steady flow of Oldroyd-B and Phan-Thien-Tanner (PTT) fluids through a two-dimensional rectangular channel is investigated computationally by means of a finite volume technique incorporating uniform collocated grids. A second-order central difference scheme is employed to handle convective terms in the momentum equation, while viscoelastic stresses are approximated by a third-order accurate quadratic upstream interpolation for convective kinematics (QUICK) scheme. Momentum interpolation method...
Technological characteristics of abrick masonry structure and their relationship with the structural behaviour /
Aktaş, Yasemin Didem; Türer, Ahmet; Department of Archaeometry (2006)
The aim of this study is to investigate the physical and mechanical properties of construction materials in relation with the structural behaviour of a historic structure. Within this framework, the brick masonry superstructure of Tahir ile Zuhre Mescidi, a XIIIth century Seljuk monument in Konya was selected as case study. The study started with the determination of the basic physical (bulk density, effective porosity, water absorption capacity), mechanical (modulus of elasticity, uniaxial compressive stre...
Citation Formats
K. Bilgin, “Computational modeling of self-assembly in deformable bodies,” M.S. - Master of Science, Middle East Technical University, 2021.