Z. Karakaya¹, B. Baranoğlu², B. Çetin³, A. Yazici⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.3, pp. 227-249, 2015, DOI:10.3970/cmes.2015.104.227

Abstract A new formulation for tracking multiple particles in slow viscous flow for microfluidic applications is presented. The method employs the manipulation of the boundary element matrices so that finally a system of equations is obtained relating the rigid body velocities of the particle to the forces applied on the particle. The formulation is specially designed for particle trajectory tracking and involves successive matrix multiplications for which SMP (Symmetric multiprocessing) parallelisation is applied. It is observed that present formulation offers an efficient numerical model to be used for particle tracking and can easily be extended for More >

M. Chang^1,2,3, Y. C. Chou^1,2, P. T. Lin^1,2, J. L. Gabayno^2,4

CMC-Computers, Materials & Continua, Vol.42, No.2, pp. 125-140, 2014, DOI:10.3970/cmc.2014.042.125

Abstract Automated optical inspection systems installed in production lines help ensure high throughput by speeding up inspection of defects that are otherwise difficult to detect using the naked eye. However, depending on the size and surface properties of the products such as micro-cracks on touchscreen panels glass cover, the detection speed and accuracy are limited by the imaging module and lighting technique. Therefore the current inspection methods are still delegated to a few qualified personnel whose limited capacity has been a huge tradeoff for high volume production. In this study, an automated optical technology for in-line… More >

Wanil Byun¹, Seung Jo Kim²

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.6, pp. 551-576, 2012, DOI:10.3970/cmes.2012.086.551

Abstract A structural eigensolver for large-scale finite element analysis is developed. The algorithms and data structures implemented in this paper are well suited for a distributed memory environment. As an eigenvalue extracting algorithm, the well-known M orthogonal block Lanczos iteration incorporated with a parallel multifrontal solver (PMFS) was chosen. Basically, for the better performance of this algorithm in parallel computation, Lanczos vector allocation, mass matrix multiplication, and M inner product procedures were efficiently implemented. And the PMFS for a linear equation which is the most time-consuming part during Lanczos iterations was improved. The idea was to More >

Jong Keun Moon¹, Seung Jo Kim²

CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.3, pp. 239-264, 2010, DOI:10.3970/cmes.2010.067.239

Abstract Large structural problems with high precision and complexity require a high-performance computation using the efficient parallel algorithm. The purpose of this paper is to present the parallel performance of thermal-structural coupled analysis tested on a parallel cluster system. In the coupled analysis, the heat transfer analysis is carried out, and then the structural analysis is performed based on temperature distribution. For the automatic and efficient connection of two parallel analysis modules, the several communication patterns were studied. The parallel performance was demonstrated for the sample and the real application problems, such as a laminated composite More >

Ji Joong Moon¹, Seung Jo Kim¹, Minhyung Lee²

CMES-Computer Modeling in Engineering & Sciences, Vol.59, No.3, pp. 275-300, 2010, DOI:10.3970/cmes.2010.059.275

Abstract This paper describes the parallelization of contact/impact simulation for fracture modeling of brittle materials using a node separation scheme (NSS). We successfully demonstrated the fracture modeling of brittle materials using a cohesive fracture model. Since a NSS continuously generates new free surfaces as the computation progresses, the methodology requires increased computational time. To perform a simulation within a reasonable time period, a parallelization study is conducted. Particular methods for effective parallelization, especially for brittle materials, are described in detail. The crucial and most difficult strategy is the management of the data structure and communication needed More >

Min Ki Kim¹, Seung Jo Kim²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 52-52, 2009, DOI:10.3970/icces.2009.012.052

Abstract A new concept of hybrid iterative-multifrontal linear solution method is presented for large scale structural analysis problems. Multifrontal solution method is the best direct solution method ever known, so it is adequate for Domain decompostion types of iterative solvers. Multifrontal solver is served as an internal subdomain solver for domain decomposition iterative solver for achieving high performance of domain decomposition iterative solver. Lagrange multiplier is introduced to enforce the continuity of interface between subdomains. And corner DOF is introduced to avoid singularities of subdomains. Hybrid solution method is expected to show good parallel performance for More >

Tae-Hyuk Ahn¹, Layne T. Watson^1,2, Yang Cao^1,1, Clifford A. Shaffer¹, William T. Baumann³

CMES-Computer Modeling in Engineering & Sciences, Vol.51, No.1, pp. 27-52, 2009, DOI:10.3970/cmes.2009.051.027

Abstract For biochemical systems, where some chemical species are represented by small numbers of molecules, discrete and stochastic approaches are more appropriate than continuous and deterministic approaches. The continuous deterministic approach using ordinary differential equations is adequate for understanding the average behavior of cells, while the discrete stochastic approach accurately captures noisy events in the growth-division cycle. Since the emergence of the stochastic simulation algorithm (SSA) by Gillespie, alternative algorithms have been developed whose goal is to improve the computational efficiency of the SSA. This paper explains and empirically compares the performance of some of these More >

T. Kipouros¹, D.M. Jaeggi², W.N. Dawes³, G.T. Parks²,A.M. Savill¹, P.J. Clarkson²

CMES-Computer Modeling in Engineering & Sciences, Vol.37, No.1, pp. 1-44, 2008, DOI:10.3970/cmes.2008.037.001

Abstract An approach to support the computational aerodynamic design process is presented and demonstrated through the application of a novel multi-objective variant of the Tabu Search optimization algorithm for continuous problems to the aerodynamic design optimization of turbomachinery blades. The aim is to improve the performance of a specific stage and ultimately of the whole engine. The integrated system developed for this purpose is described. This combines the optimizer with an existing geometry parameterization scheme and a well-established CFD package. The system's performance is illustrated through case studies -- one two-dimensional, one three-dimensional -- in which… More >

Jin Yeon Cho¹, Yun Hyuk Choi², You Me Song³, Chang Sik Kim⁴

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.3, pp. 151-158, 2007, DOI:10.3970/icces.2007.004.151

Abstract In this work, PDSL(pre-detection sort last) and SDSL(strip-wise decomposition sort last) parallel visualization algorithms are proposed for efficient visualization of massive data generated from large-scale parallel finite element analysis through investigating the characteristics of distributed parallel finite element analysis procedure. The proposed parallel visualization algorithms are based on the sort last approach, and designed to be highly compatible with the characteristics of domain-wise computation in parallel finite element analysis. To investigate the performances of proposed algorithms, in-house software is developed by applying the binary tree network communication pattern along with the proposed sorting algorithms, and More >

J. Ma¹, H. Lu¹, B. Wang¹, S. Roy¹, R. Hornung², A. Wissink², R. Komanduri^1,3

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.2, pp. 135-152, 2005, DOI:10.3970/cmes.2005.008.135

Abstract In the simulation of a wide range of mechanics problems including impact/contact/penetration and fracture, the material point method (MPM), Sulsky, Zhou and Shreyer (1995), demonstrated its computational capabilities. To resolve alternating stress sign and instability problems associated with conventional MPM, Bardenhagen and Kober (2004) introduced recently the generalized interpolation material point (GIMP) method and implemented for one-dimensional simulations. In this paper we have extended GIMP to 2D and applied to simulate simple tension and indentation problems. For simulations spanning multiple length scales, based on the continuum mechanics approach, we present a parallel GIMP computational method… More >