C. Nikhare¹, K. Narasimhan²

CMC-Computers, Materials & Continua, Vol.7, No.1, pp. 1-8, 2008, DOI:10.3970/cmc.2008.007.001

Abstract Hydroforming is a manufacturing process that uses a fluid medium to form a component by using high internal pressure. Tube and sheet hydroforming has gained increasing interest in the automotive and aerospace industries because of its many advantages such as part consolidation, good quality of the formed parts etc. The main advantage is that the uniform pressure can be transferred to every where at the same time. Forming limit is the limit of the component up to that extent it can be formed safely. While analyzing hydroforming process, it is often assumed that the limit… More >

H.S. Lee¹, W.S. Chu¹, Y.C. Kang¹, H.J. Kang¹, S.H. Ahn²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.3, pp. 195-200, 2007, DOI:10.3970/icces.2007.004.195

Abstract The fuel cell is one of promising environment-friendly energy sources for the next generation. The bipolar plate is a major component of the Proton Exchange Membrane (PEM) fuel cell stack, and it takes a large portion of stack volume, weight and cost. In this study, as alternative materials for bipolar plate of PEM fuel cells, graphite composites were fabricated by compression molding and by machining. Graphite particles mixed with epoxy resin were used as the main substance to provide electric conductivity. Flow channels were fabricated by compression molding applying design of experiments (DOE) in order More >

V.C. Santos¹, P.S. Lopes¹, R. Gärtner², A.B. Jorge¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.2, pp. 53-58, 2007, DOI:10.3970/icces.2007.004.053

Abstract This work presents an approach for weight and reliability optimization of aeronautical armors. Military and police helicopters are usually exposed to highly risky situations, with a high probability for these aircrafts to be hit by projectiles. In this context, floor aircraft armor can be used to protect the crews' lives. However, the armoring of an aircraft causes an increase in weight. If this extra weight is poorly arranged, the changes in aircraft centroid position may even destabilize the aircraft. Thus, it is essential to design an armor not only to protect the aircraft, but also… More >

W. Chen¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.4, pp. 177-188, 2007, DOI:10.3970/icces.2007.003.177

Abstract This paper is concerned with the two new boundary-type radial basis function collocation schemes, boundary knot method (BKM) and boundary particle method (BPM). The BKM is developed based on the dual reciprocity theorem, while the BKM employs the multiple reciprocity technique. Unlike the method of fundamental solution, the two methods use the non-singular general solution instead of the singular fundamental solution to circumvent the controversial artificial boundary outside the physical domain. Compared with the boundary element method, both BKM and BPM are meshfree, super-convergent, integration-free, symmetric, and mathematically simple collocation techniques for general PDEs. In More >

M.V. Hosur¹, F.H. Chowdhury¹, S. Jeelani¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.4, pp. 119-124, 2007, DOI:10.3970/icces.2007.002.119

Abstract In the present study, Nanomer® I-28E, organically modified montmorillonite nanoclay supplied by Nanocor Inc., was used to modify SC-15, a toughened epoxy system using sonication route. Different weight percentage ranging from 1-3% of nanoclay was used. The modified epoxy was then used to fabricate 15-layer plain weave carbon/epoxy composite laminates using vacuum assisted resin transfer molding (VARTM) method. Samples of size 100 x 100 mm were cut from the laminates and were subjected to low-velocity impact loading using an instrumented drop-weight system (Dynatup Model 8210) at three different energy levels of 10, 20 and 30J. More >

M-A Lavoie¹, A. Gakwaya¹, M. Nejad Ensan², D.G. Zimcik²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.4, pp. 111-118, 2007, DOI:10.3970/icces.2007.002.111

Abstract This paper reviews numerical methods that are currently available to simulate bird strike as well as the theory of the event. It also summarizes important parameters and provides guidelines as to how to set up the analysis and how to evaluate a model. The information provided is based on physical properties and available results regarding a bird and its behaviour upon impact. The simulations have been performed with LS-DYNA 970 but can be done in similar dynamic finite elements analysis codes. More >

I. Cerný ¹, V. Linhart¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.4, pp. 161-166, 2007, DOI:10.3970/icces.2007.001.161

Abstract Two different cases with the aim to show, how important the crack closure phenomenon can be in reality and can affect eventual crack growth behaviour by an unexpected way are described and discussed in the paper, namely: (i) a favourable effect of fretting oxidation crack closure in air which can disappear in oil environments, typical for many machinery applications and (ii) a favourable effect of crack closure occurring as a results of corrosion products in corrosive environments, which would normally increase crack growth rate by stress corrosion and corrosion fatigue mechanisms. More >

T. Nishioka¹, M.Kogame², T. Fujimoto¹, G. Okamoto¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.3, pp. 113-118, 2007, DOI:10.3970/icces.2007.001.113

Abstract In this study, we observed C.G.S. fringe pattern of dynamic fracture under impact load by an ultra high-speed CCD video camera, and stress intensity factors KI, KII are evaluated from the experimental measurements. From the evaluation of stress intensity factors, local mode I condition is observed during crack propagation. On the other hand, concentrated load is obtained by the experimental devices in this study. We suggest the least square method to estimate loading value based on the C.G.S. fringe pattern analyses. More >

C. Soutis¹, K. Diamanti¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.2, pp. 49-54, 2007, DOI:10.3970/icces.2007.001.049

Abstract A cost and time effective inspection strategy for in-service health monitoring of composites is demonstrated using the fundamental anti-symmetric A0 Lamb mode at frequencies of 15-20 kHz. In principle, this method involves analysis of the transmitted and/or reflected wave after interacting with the test-piece boundaries or discontinuities (defects). In the present work, the applicability of the technique to composite sandwich structures is explored. More >

Jun Zhang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.2, pp. 91-96, 2007, DOI:10.3970/cmes.2007.022.091

Abstract The most commonly used wavelets for image processing are the tensor-product of univariate wavelets, which have a disadvantage of giving a particular importance to the horizontal and vertical directions. In this paper, a new class of wavelet, non-separable wavelet, is investigated for image compression applications. The comparative results of image compression preprocessed with two different kinds of wavelet transform are presented: (1) non-separable wavelet transform; (2) tensor-product wavelet transform. The results of our experiments show that in the same vanishing moment, the non-separable wavelets perform better than the tensor-product wavelets in dealing with still images. More >