Poisson's ratio is an important factor for fracture of functionally graded materials (FGMs). It may have significant influence on fracture parameters (e.g. stress intensity factors and T-stress) for a crack in FGMs under mixed-mode loading conditions, while its effect on such parameters is negligible in homogeneous materials. For instance, when tension load is applied in the direction parallel to material gradation, the fracture parameters may show significant influence on the Poisson's ratio. This paper uses a new formulation, so-called non-equilibrium formulation, of the interaction integral method. It also presents a few numerical examples where Poisson's ratio is assumed either constant or linearly varying function, and Young's modulus is assumed to be exponential or hyperbolic-tangent function.

This paper introduces an object-oriented programming approach into the development of a general-purpose simulation framework for the numerical modeling of microstructure evolution at the mesoscopic length level. The design requirements of this framework are discussed, and an analysis from the standpoint of object-oriented programming is performed. Based on this framework, a Monte Carlo grain growth algorithm with improved efficiency and accuracy has been developed. This simulation framework is expected to represent a reliable software module of a multi-scale microstructure prediction system for materials processing.

In the present paper a simple mixed-hybrid element for the linear analysis of Reissner-Mindlin plates is discussed. The element is derived from a modified Reissner functional and standard bilinear (isoparametric) interpolation for displacement and rotations is assumed whereas local stresses (rather than stress resultants and moments) are explicitly modelled. It is assumed that in plane shear stresses are not a priori symmetric. This choice allows to decouple the equilibrium equations, and involves introducing an in-plane infinitesimal rotation field, corresponding to drilling degrees of freedom. Out-of-plane shear stresses are then obtained such that equilibrium equations are exactly satisfied. The proposed element does not exhibit locking effects at all: i.e. the shear deformation energy is zero in the thin plate limit. Details of the formulation are provided, and the performances of the element are assessed with reference to well-established benchmark problems.

A lattice Boltzmann method on nonuniform mesh is developed for the simulation of incompressible flows. The computation mesh is uncoupled from the lattice. The particle distribution function on the mesh is obtained using the Lagrange interpolation technique at each time step. Comparison with the finite difference solutions for the two-dimensional driven cavity flow and the experimental results for flow around a circular cylinder shows that the present scheme not only can predict the flow separation characteristic satisfactorily with much less mesh but also increase the computational stability. The influence of the mesh structure and interpolation on the results will also be discussed.

International Journal of Computational Engineering ScienceVol. 05, No. 02, pp. 259-270 (2004) SPECIAL ISSUE ON RECENT ADVANCES IN COMPUTATIONAL SCIENCE AND ENGINEERING; EDITED BY H. P. LEE AND K. KUMARNo AccessCOMPUTATIONAL MATERIAL TESTING OF PRE-DAMAGED METALS USING DAMAGE MECHANICS MODELSYUTAKA TOI and SATOSHI HIROSEYUTAKA TOIInstitute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan Search for more papers by this author and SATOSHI HIROSEInstitute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan Search for more papers by this author https://doi.org/10.1142/S1465876304002356Cited by:0 Next AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractThe elasto-viscoplastic constitutive equation considering damage is formulated, based on the concept of continuum damage mechanics. It employs the viscoplastic strain, which was originally given by Perzyna and extended by Murakami to consider the effect of damage. The unified form of damage evolution equation given by Lemaitre is extended to consider the effect of damage type and strain rate. The constitutive modeling is identified, based on static/dynamic tensile tests and fatigue tests for steel (SM490A) and aluminum (2219-T87). The identified models are used to predict the static/dynamic, tensile behaviors of pre-strained steel and pre-fatigued aluminum. The predicted results have agreed well with the corresponding experimental results. References J. Lemaitre , A Course on Damage Mechanics , 2nd edn. ( Springer , 1996 ) . Crossref, Google Scholar J. Skrzypek and A. Ganczarski , Modeling of Material Damage and Failure of Structures (Theory and Applications) ( Springer , 1999 ) . Crossref, Google ScholarD. Krajcinovic, Int. J. Solids Structures 37, 267 (2000). Crossref, Google ScholarM. Itabashi and H. Fukuda, Technology, Law and Insurance 4, 37 (1999). Crossref, Google ScholarM. Itabashiet al., Sino-Japanese Symp. Deformation/Fracture of Solids 41 (1997). Google ScholarM. Itabashi and H. Fukuda, Journal of Materials Processing Technology 117-3, (2001). Google ScholarP. Perzyna, Arch. Mech. 32-3, 403 (1986). Google ScholarS. Murakami, Transactions of the JSME 60-578, 230 (1994). Google ScholarJ. Lemaitre, Comput. Methods Appl. Mech. Engrg. 51, 31 (1985). Crossref, Google ScholarJ. Lemaitre and J. P. Sermage, Computational Mechanics 30, 84 (1997). Google ScholarY. Toi and S. Hirose, Transactions of the Japan Society of Mechanical Engineers, Series (A) 69-679, 530 (2003). Google Scholar FiguresReferencesRelatedDetails Recommended Vol. 05, No. 02 Metrics History PDF download

Two higher-order compact finite difference approaches, the Hermitian and the Lax-Wendroff are examined by applying them to the viscous Burgers' equation. The difference equations obtained by the two methods were integrated in time through the third-order Strong-Stability-Preserving Runge-Kutta scheme. Absolute errors are computed by using an exact solution. The results are also compared with a second order central difference scheme. The Hermitian approach is far easier to implement. On uniform grids the Lax-Wendroff scheme produces smaller errors during the initial stages, but both methods are equally good for larger durations of integration. The convergence rate of the Hermitian scheme is slightly higher than the Lax-Wendroff scheme although both are of fourth order. Both schemes are unstable beyond a certain step size in time and space. When numerical boundary conditions are imposed, second-order conditions produce the best results whereas linear extrapolation proved to be the worst. It was also observed that large domains were required to implement the numerical boundary conditions properly. There was no detrimental effect on the accuracy of the results obtained through either of the two schemes when the size of the domain was greatly increased. Both schemes showed remarkable improvement in accuracy when clustered grids were employed. However much smaller time steps are required for stable solutions.

International Journal of Computational Engineering ScienceVol. 05, No. 01, pp. 81-89 (2004) No AccessEVOLUTIONARY PROGRAMMING BASED ECONOMIC DISPATCH WITH LINE FLOW CONSTRAINTSP. SOMASUNDARAM, K. KUPPUSAMY, and R. P. KUMUDINI DEVIP. SOMASUNDARAMSchool of Electrical and Electronics Engineering, Anna University, Chennai, Tamil Nadu 600 025, India Search for more papers by this author , K. KUPPUSAMYSchool of Electrical and Electronics Engineering, Anna University, Chennai, Tamil Nadu 600 025, India Search for more papers by this author , and R. P. KUMUDINI DEVISchool of Electrical and Electronics Engineering, Anna University, Chennai, Tamil Nadu 600 025, India Search for more papers by this author https://doi.org/10.1142/S1465876304002277Cited by:1 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractThis paper presents an efficient, simple and new method for solving Economic Dispatch (ED) problem with line flow constraints through the application of Evolutionary Programming (EP). The controllable system quantities in the base-case state are optimized to minimize some defined objective function subject to the base-case operating constraints. A 10-bus system is taken for investigation. The ED results obtained using EP are compared with those obtained using quadratic programming. The investigations reveal that the proposed algorithm is relatively simple, reliable, efficient and suitable for on-line applications.Keywords:Power System OptimizationEconomic DispatchEvolutionary ProgrammingLine Flow Constraints References B. H. Chowdhury and S. Rahman, IEEE Transaction on power systems 5(4), 1248 (1990). Crossref, Google Scholar Nanda, L. Hari and M. L. Kothari, IEE Proceedings-C 141(1), 1 (1994). Google ScholarJ. Nandaet al., IEE Proceedings-C 139(1), 39 (1992). Google ScholarJ. Y. Fan and L. Zhang, IEEE Transactions on Power Systems 13(2), 320 (1998). Crossref, Google ScholarP. K. Hota, R. Chakrabarti and P. K. Chattopadhyay, Institute of Engineers (India) Journal-EL 81, 21 (2000). Google ScholarJ. Nanda and R. Badri Narayanan, Electrical Power and Energy Systems 24, 723 (2002). Crossref, Google Scholar D. B. Fogel , Evoluationary Computation: Toward a New Philosophy of Machine Intelligence ( IEEE Press , USA , 1995 ) . Google ScholarL. L. Lai and J. T. Ma, IEEE Transactions on Power Systems 12(1), 198 (1997). Crossref, Google ScholarH. T. Yang, P. C. Yang and C. L. Huang, IEEE Transactions on Power Systems 11(1), 112 (1996). Crossref, Google ScholarK. P. Wong and J. Yuryevich, IEEE Transactions on Power Systems 13(2), 301 (1998). Google ScholarT. Jayabarathi, G. Sadasivam and V. Ramachandran, Electric Power Systems Research 52, 261 (1999). Crossref, Google ScholarT. Jayabarathi and G. Sadasivam, European Transaction on Electrical Power 10(3), 167 (2000). Crossref, Google ScholarP. Attaviriyanupapet al., IEEE Transactions on Power Systems 17(2), 411 (2002). Crossref, Google Scholar FiguresReferencesRelatedDetailsCited By 1FDR PSO-based Transient Stability Constrained Optimal Power Flow Solution for Deregulated Power IndustryM. Anitha, S. Subramanian and R. Gnanadass28 Aug 2007 | Electric Power Components and Systems, Vol. 35, No. 11 Recommended Vol. 05, No. 01 Metrics History KeywordsPower System OptimizationEconomic DispatchEvolutionary ProgrammingLine Flow ConstraintsPDF download

International Journal of Computational Engineering ScienceVol. 04, No. 04, pp. 853-868 (2003) No AccessAN ACCURATE SCHEME FOR GAS DYNAMICAL CALCULATIONSMAHMOOD K. MAWLOOD, WAQAR ASRAR, ASHRAF A. OMAR, and MEGAT M. H. M. AHMADMAHMOOD K. MAWLOODDepartment of Aerospace Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor D. E., Malaysia Search for more papers by this author , WAQAR ASRARDepartment of Mechanical Engineering, Faculty of Engineering, International Islamic University Malaysia, Jalan Gombak, 53100 Kuala Lumpur, MalaysiaCorresponding author. Search for more papers by this author , ASHRAF A. OMARDepartment of Mechanical Engineering, Faculty of Engineering, International Islamic University Malaysia, Jalan Gombak, 53100 Kuala Lumpur, Malaysia Search for more papers by this author , and MEGAT M. H. M. AHMADDepartment of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor D. E., Malaysia Search for more papers by this author https://doi.org/10.1142/S1465876303002209Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractAn accurate numerical method is developed for computing inviscid flows containing discontinuities. The method is based on flux vector splitting (FVS) and a third-order accurate upwind-biased compact finite-difference scheme. Two different flux splitting techniques, namely, the kinetic flux vector splitting (KFVS) and van Leer's flux splitting, are used to solve one-dimensional gas dynamics test problems. The idea of total variation diminishing (TVD) is employed to suppress spurious numerical oscillations. The stability and high-order accuracy of the scheme are shown.Keywords:High-Order Compact SchemesTotal Variation DiminishingEuler EquationsRunge-Kutta Methods References C. W. Shu, SIAM. J. Sci. Statist. Comput. 9, 1073 (1988). Crossref, Google Scholar S. Gottlieb and C. W. Shu, ICASE Report No. 2000-15, 2000 . Google ScholarS. K. Lele, J. Comp. Phys. 103, 16 (1992), DOI: 10.1016/0021-9991(92)90324-R. Crossref, Google ScholarJ. A. Ekaterinaris, J. Comp. Phys. 156, 272 (1999), DOI: 10.1006/jcph.1999.6360. Crossref, Google ScholarJ. A. Ekaterinaris, AIAA J. 38, 1594 (2000), DOI: 10.2514/2.1142. Crossref, Google ScholarM. R. Visbal and D. V. Gaitonde, AIAA J. 10, 358 (1999). Google ScholarX. Deng and H. Maekawa, J. Comp. Phys. 130, 77 (1997), DOI: 10.1006/jcph.1996.5553. Crossref, Google ScholarP. L. Roe, J. Comp. Phys. 43, 357 (1981), DOI: 10.1016/0021-9991(81)90128-5. Crossref, Google Scholar Hartenet al., J. Comp. Phys. 71, 231 (1987), DOI: 10.1016/0021-9991(87)90031-3. Crossref, Google Scholar Cockburn and C. W. Shu, SIAM J. Numer. Analy. 31, 607 (1994), DOI: 10.1137/0731033. Crossref, Google ScholarN. A. Adams and K. Shariff, J. Comp. Phys. 127, 27 (1996), DOI: 10.1006/jcph.1996.0156. Crossref, Google Scholar Fu and Y. Ma, J. Comp. Phys. 134, 1 (1997), DOI: 10.1006/jcph.1996.5492. Crossref, Google ScholarX. Zhong, J. Comp. Phys. 144, 662 (1998), DOI: 10.1006/jcph.1998.6010. Crossref, Google ScholarK. S. Ravichandran, J. Comp. Phys. 130, 161 (1997), DOI: 10.1006/jcph.1996.5561. Crossref, Google ScholarM. H. Carpenter and D. Gotlieb, J. Comp. Phys. 108, 272 (1993), DOI: 10.1006/jcph.1993.1182. Crossref, Google ScholarJ. L. Steger and R. F. Warming, J. Comp. Phys. 40, 263 (1981), DOI: 10.1016/0021-9991(81)90210-2. Crossref, Google ScholarB. Van Leer, Lecture Notes in Physics 170 (1982) p. 507. Google ScholarS. M. Deshpande and P. S. Kulkarni, Computers Math. Applic. 35, 75 (1998), DOI: 10.1016/S0898-1221(97)00259-9. Crossref, Google Scholar Hirsch , Numerical Computation of Internal and External Flows, Vol. 2: Computational Methods for Inviscid and Viscous Flows ( John Wiley & Sons , UK , 1990 ) . Google ScholarG. A. Sod, J. Comp. Phys. 27, 1 (1978), DOI: 10.1016/0021-9991(78)90023-2. Crossref, Google ScholarC. W. Shu and S. Osher, J. Comp. Phys. 83, 32 (1989), DOI: 10.1016/0021-9991(89)90222-2. Crossref, Google Scholar FiguresReferencesRelatedDetails Recommended Vol. 04, No. 04 Metrics History Revised 26 May 2003 KeywordsHigh-Order Compact SchemesTotal Variation DiminishingEuler EquationsRunge-Kutta MethodsPDF download

Chemical reactions can be very complex and frequently produce undesired side products within short time spans. Investigation of such reactions necessitates in-situ measurements for analysis. We present a novel micro-reactor design enabling non-invasive and spatially highly resolved in-situ reaction analysis using Raman spectroscopy. The reactor consists of a stainless steel base containing milled channels covered with anodically bonded pyrex glass. The educt flow rate is finely controlled by a motor-driven feed pump. Monitoring of an exemplary test reaction by Raman spectroscopic means was achieved by recording spectra at various discrete sampling points along the reaction channel. The glass window allows visual observation of the channels by optical microscopy and does not affect, in contrast to infrared spectroscopy, the Raman spectroscopic signal. Taking Raman spectra along the reaction channel at different loci enabled us to determine the reaction kinetics of a fast chemical reaction.