Chun-Lang Yeh¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.2, pp. 81-94, 2009, DOI:10.3970/icces.2009.009.081

Abstract In this study, the vaporization process of a nanojet is investigated by molecular dynamics simulation. Liquid argon nanojet made of 44000 Lennard-Jones molecules is investigated under various simulation parameters to examine their influence on the nanojet vaporization process. Snapshots of the molecules, evolution of the density field, and evolution of the intermolecular force are analyzed. The present simulation results can provide insight into the fundamental mechanism of the atomization process and will be helpful for the design of nanojet devices such as nano-printer or nano-sprayer. More >

T. Yamaguchi¹, T. Ishikawa², Y. Imai²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.2, pp. 79-80, 2009, DOI:10.3970/icces.2009.009.079

Abstract Human cardiovascular system is always under the integrated nervous and humoral control of the whole body, i.e. in homeostasis. Multiple feedback mechanisms with mutual interactions among systems, organs, and even tissues provide integrated control of the entire body. These control mechanisms have different spatial coverages, from the micro- to macroscale, and different time constants, from nanoseconds to decades. We think that these variations in spatial as well as temporal scales should be taken into account in discussing phenomena in the cardiovascular system.
In this background,we have been investigatingthe cardiovascular system over micro to macro levels by using conjugated computational mechanics… More >

T. Ishikawa¹, H. Fujiwara¹, N. Matsuki², R. Lima³, Y. Imai¹, T. Yamaguchi²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.2, pp. 77-78, 2009, DOI:10.3970/icces.2009.009.077

Abstract In a small artery, the blood is no longer assumed as a homogeneous fluid, because the size of blood cells cannot be neglected compared to the generated flow field. In such a case, we need to treat the blood as a multi-phase fluid, and investigate the motion of individual cells in discussing the flow field. Blood may be modelled as a suspension of red blood cells (RBCs) in plasma, because about 99% of volume fraction of blood cells is RBCs.
In order to measure a blood flow experimentally, various methods have been employed. However, most of conventional techniques are difficult… More >

G. Yoon¹, K. Bong², J. Kim³, I.H. Ahn⁴, K. Eom⁵, S. Na⁶

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.2, pp. 53-60, 2007, DOI:10.3970/icces.2007.002.053

Abstract This paper presents multi-component mode methodology applicable to biomolecular structures for understanding the dynamics of proteins. Even though the conventional normal mode analysis has been contributed for analyzing the dynamics and thermal fluctuations of proteins, it frequently encounters with the computational prohibition for large proteins due to memory requirement. To overcome the conventional computational limitations, the drawback motivates one to develop various model reduction methods, which reduces the degrees of freedom of the full model so as to decrease the computational expense, while the computational accuracy is maintained. Our results demonstrate that the multi-component modal analysis applied to the biomolecular… More >

J.W. Choi¹, S.H. Yoo¹, J.B. Kim¹, E.J. Park¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.2, pp. 47-52, 2007, DOI:10.3970/icces.2007.002.047

Abstract A semi-analytical solution by beam theory and finite element solutions are obtained for normal deflection of a plate with a surface crack under tensile stress. The semi-analytical solution consists of the deflection of a beam and the half-space or full-space solution. Also finite element solutions are obtained and compared with these analytical solutions. These solutions can be used as reference data for non-destructive evaluation of a surface crack. More >

F.C. Araújo¹, L.J. Gray²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.2, pp. 41-46, 2007, DOI:10.3970/icces.2007.002.041

Abstract This paper is concerned with the solution of boundary-element models based on substructuring. Structured matrix-vector products and the matrix-copy option are proposed to increase the efficiency of algorithms based on Krylov solvers. The former technique was designed to avoid the excessive number of conditional tests during solver iterations, and the latter one, to avoid the repeated calculation of coefficient matrices for identical subregions. Potential applications of the algorithm to composite materials, and to develop parallel codes, are noted. More >

Doo Kie Kim¹, Dong Hyawn Kim², Seong Kyu Chang¹, Sang Kil Chang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.2, pp. 35-40, 2007, DOI:10.3970/icces.2007.002.035

Abstract The stability numbers determining the Armor units are very important to design breakwaters, because armor units are designed for defending breakwaters from repeated wave loads. This study presents a probabilistic neural network (PNN) for predicting the stability number of armor blocks of breakwaters. PNN used the experimental data of van der Meer as train and test data. The estimated results of PNN were compared with those of empirical formula and previous artificial neural network (ANN) model. The comparison results showed the efficiency of the proposed method in the prediction of the stability numbers in spite of data incompleteness and incoherence.… More >

Doo Kie Kim¹, Seong Kyu Chang¹, Sang Kil Chang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.1, pp. 29-34, 2007, DOI:10.3970/icces.2007.002.029

Abstract Accurate and realistic strength estimation before the placement of concrete is highly desirable. In this study, the advanced probabilistic neural network (APNN) was proposed to reflect the global probability density function by summing the heterogeneous local probability density function automatically determined in the individual standard deviation of variables. Currently, the estimation of the compressive strength of concrete is performed by a probabilistic neural network (PNN) on the basis of concrete mix proportions, and the PNN is improved by the iteration method. However, an empirical method has been incorporated to specify the smoothing parameter in the PNN technique, causing significant uncertainty… More >

L. Rodríguez-Tembleque¹, J.A. González¹, R. Abascal¹, K.C. Park², C.A. Felippa²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.1, pp. 21-28, 2007, DOI:10.3970/icces.2007.002.021

Abstract This work presents an interface treatment method based on localized Lagrange Multipliers (LLM) to solve frictional contact problems between two 3D elastic bodies. The connection between the solids is done using a displacement frame intercalated between the interfaces meshes, and the LLM are collocated at the interface nodes. The Boundary Elements Method (BEM) is used to compute the influence coefficients of the surface points involved, and contact conditions are imposed using projection functions. The LLM provides a partitioned formulation which preserves software modularity, facilitates non-matching meshes treatment and passes the contact patch test [4]. More >

J. París¹, M. Casteleiro¹, F. Navarrina¹, I. Colominas¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.1, pp. 13-20, 2007, DOI:10.3970/icces.2007.002.013

Abstract Topology structural optimization problems have been usually stated in terms of a maximum stiffness (minimum compliance) approach. In this kind of formulations, the aim is to distribute a given amount of material in a certain domain, so that the stiffness of the resulting structure is maximized for a given load case. In addition, no stress or displacement constraints are taken into account. This paper presents a different strategy: a minimum weight Finite Element formulation for optimization of continuum structures subjected to stress constraints. We propose two different approaches to take into account the stress constraints in the optimization formulation. The… More >