S. Masuda¹, H. Noguchi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.11, No.3, pp. 131-144, 2006, DOI:10.3970/cmes.2006.011.131

Abstract This paper presents a novel and accurate technique for modeling discontinuous derivatives in meshfree methods, which will be used in the analysis of structures with material interfaces. The novelty lies in the formulation of the Moving Least Squares Approximation (MLSA) scheme where an introduced discontinuous derivative basis function replaces the conventional linear basis function. Furthermore, it is easy to implement this novelty into existing meshfree methods, such as the Element Free Galerkin (EFG) method, which are based on the MLSA scheme. The successful analyses of one and two-dimensional structures with material interfaces demonstrate the potential More >

Sunil Punjabi¹, K. Muralidhar², P. K. Panigrahi²

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.2, pp. 95-106, 2006, DOI:10.3970/fdmp.2006.002.095

Abstract Convection in a differentially heated two-layer system consisting of air and water was studied experimentally, using laser-interferometry. The cavity used for flow visualization was square in cross-section and rectangular in-plan having dimensions of 447 × 32 × 32 mm³. Experiments performed over different layer thicknesses of water filled in a square cross-section cavity, the rest being air, are reported in the present work. The following temperature differences for each layer height were imposed across the hot and the cold walls of the superposed fluid layers: (i) ΔT=10K and (ii)ΔT =18 K. The present study was aimed… More >

K. Matsunaga¹, H. Kawamura¹

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.1, pp. 59-64, 2006, DOI:10.3970/fdmp.2006.002.059

Abstract Existing studies on solidification phenomena mainly focused on the solidification processes per se. In real systems, however, one cannot neglect the effects of molten material convective flow, such as natural and thermocapillary convection (they strongly affect the resulting quality of the solidified materials). The present study aims to experimentally investigate on the effect of the thermocapillary flow upon the directional solidification in a liquid layer with a free upper surface. If no free surface exists, the solid--liquid interface (SLI) is vertical and straight, while, with the free surface, the SLI is inclined against the wall-normal More >

A.Kurenkov¹, A.Thess², H.Babovsky³

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.1, pp. 47-58, 2006, DOI:10.3970/fdmp.2006.002.047

Abstract A possibility for the determination of the interface between two electrically conducting fluids in cylindrical geometry is presented. The fluids with different conductivities are situated in an infinite cylinder. Along the axis of the cylinder a homogeneous electrical current is applied. The perturbation of the interface leads to an inhomogeneous electrical current and, therefore, results in an electrical potential change in the fluids and a magnetic field modification outside the fluids. The dependence of the electrical potential on the interface shape is obtained analytically. The interface profile is then recovered from data of the electrical More >

M. Kassemi¹, Y. Wang², S. Barsi^1,3, B.T.F. Chung²

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.1, pp. 27-46, 2006, DOI:10.3970/fdmp.2006.002.027

Abstract Microgravity experiments, especially materials processing experiments, have often been hampered by presence of unwanted bubbles. In this work, the effect of thermocapillary convection generated by a bubble on the Bridgman growth of a dilute binary alloy in microgravity is investigated numerically. The model is based on the quasi-steady Navier-Stokes equations for the fluid flow in the melt coupled with the conservation equations for transport of energy and species in the growth ampoule. Numerical results indicate three different growth regimes based on the distance between the bubble and the growth interface: a diffusion dominated regime that More >

M.El-Gammal¹, J.M.Floryan¹

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.1, pp. 17-26, 2006, DOI:10.3970/fdmp.2006.002.017

Abstract Interface deformation and thermocapillary rupture in a cavity with free upper surface subject to concentrated heating from above is investigated. The dynamics of the process is modulated by placing different amounts of liquid in the cavity. The results determined for large Biot and zero Marangoni numbers show the existence of limit points beyond which steady, continuous interface cannot exist and processes leading to the interface rupture develop. Evolution of the limit point as a function of the mass of the liquid is investigated. The topology of the flow field is found to be qualitatively similar, More >

G. Mishuris¹, A. Öchsner², G. Kuhn³

CMC-Computers, Materials & Continua, Vol.4, No.3, pp. 137-152, 2006, DOI:10.3970/cmc.2006.004.137

Abstract Nonclassical transmission conditions for dissimilar elastic structures with imperfect interfaces are investigated. The thin interface zone is assumed to be soft or stiff in comparison with the bonded materials and the transmission conditions for stiff interfaces are evaluated based on asymptotic analysis. The accuracy of the transmission conditions is clarified not only in terms of asymptotic estimate, but, which is especially important for users, also in values by accurate FEM calculations. The ranges of applicability of the conditions are discussed. More >

Shen Yubin¹, Xie Huicai^1,2, Den Wei¹

CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 49-54, 2006, DOI:10.3970/cmc.2006.003.049

Abstract Bonding an overlay of new concrete onto the damaged concrete is a usual repair method. Because of the different shrinkage rate of the new and old concrete, restrained shrinkage cracks will appear in the new concrete. The cracks will reduce durability and strength of the repaired structure. A new repair method using an interface layer of carbon fiber reinforced cement mortar between new and old concrete was developed in this paper. The new method was found to be very effective in reducing shrinkage cracking of repaired beams and slabs. Comparing with normal repaired beams, the More >

M. S. Alam¹, M.A. Wahab^1,2

Structural Durability & Health Monitoring, Vol.1, No.3, pp. 171-184, 2005, DOI:10.3970/sdhm.2005.001.171

Abstract Fatigue life of curved structural joints in ship structures under constant amplitude cyclic loading has been studied in this research. A new approach for the simulation of fatigue crack growth in welded joints has been developed and the concept has been applied to welded curved butt-joints. The phenomena of crack propagation and interface debonding can be regarded as the formation of new surfaces. Thus, it is possible to model these problems by introducing the mechanism of surface formation. In the proposed method, the formation of new surface is represented by interface element based on the… More >

X. Neil Dong^1,2, Xiaohui Zhang¹, X. Edward Guo¹

Molecular & Cellular Biomechanics, Vol.2, No.2, pp. 63-68, 2005, DOI:10.3970/mcb.2005.002.063

Abstract In human cortical bone, cement lines (or reversal lines) separate osteons from the interstitial bone tissue, which consists of remnants of primary lamellar bone or fragments of remodeled osteons. There have been experimental evidences of the cement line involvement in the failure process of bone such as fatigue and damage. However, there are almost no experimental data on interfacial properties of cement lines in human cortical bone. The objective of this study is to design and assemble a precision and computer controlled osteon pushout microtesting system, and to experimentally determine the interfacial strength of cement… More >