International Journal of Theoretical and Applied Multiscale Mechanics http://www.inderscience.com/browse/index.php?journalID=293&year=2011&vol=2&issue=2 Inderscience Publishers Ltd en-uk International Journal of Theoretical and Applied Multiscale Mechanics 1755-9995 1756-0004 © 2011 Inderscience Publishers Ltd editor@inderscience.com https://www.inderscience.com/images/files/coverImgs/ijtamm_scoverijtamm.jpg http://www.inderscience.com/browse/index.php?journalID=293&year=2011&vol=2&issue=2 http://www.inderscience.com/link.php?id=43533 Modelling the interaction of dislocations with internal boundaries and free surfaces is essential to understanding the effect of microstructure on dislocation motion. However, dislocation dynamics methods rely on infinite domain solutions of dislocation fields which makes modelling of heterogeneous materials difficult. A finite domain dislocation dynamics capability is presented that resolves both the dislocation array and polycrystalline structure in a compatible manner so that free surfaces and material interfaces are easily treated. In this approach the polycrystalline structure is accommodated using the Generalised Finite Element Method (GFEM) (Simone et al., 2006) and the displacement due to dislocations is added to the displacement approximation. Modelling dislocations in a polycrystal using the Generalised Finite Element Method
J. Robbins; T.E. Voth
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 95 - 110
Modelling the interaction of dislocations with internal boundaries and free surfaces is essential to understanding the effect of microstructure on dislocation motion. However, dislocation dynamics methods rely on infinite domain solutions of dislocation fields which makes modelling of heterogeneous materials difficult. A finite domain dislocation dynamics capability is presented that resolves both the dislocation array and polycrystalline structure in a compatible manner so that free surfaces and material interfaces are easily treated. In this approach the polycrystalline structure is accommodated using the Generalised Finite Element Method (GFEM) (Simone et al., 2006) and the displacement due to dislocations is added to the displacement approximation.

]]> 10.1504/IJTAMM.2011.043533 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 95 - 110 J. Robbins; T.E. Voth Dynamic Material Properties, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA. ' Exploratory Simulation Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA dislocation modelling polycrystals GFEM generalised FEM ?nite element method internal boundaries free surfaces microstructure nickel dislocations dislocation motion dislocation dynamics displacement. 2011-11-04T23:20:50-05:00 2 2 95 110 2011-11-04T23:20:50-05:00 http://www.inderscience.com/link.php?id=43534 This paper describes a study of exposed anchors in shear such as those in a typical column footing connection with a grout leveling pad. Two groups of double-shear tests of threaded rods (ASTM A193 Grade B7) were conducted along with finite element analyses to simulate the behaviour of exposed anchors in shear. The study indicated that the exposed length and boundary conditions of exposed anchors significantly affects the load-carrying capacities and the corresponding failure modes because the anchors are subjected to combined bending, shear, and tension. Design equations were proposed for exposed anchors based on the experimental and numerical results. Simulation and design of exposed anchor bolts in shear
Zhibin Lin; Derek Petersen; Jian Zhao; Ying Tian
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 111 - 129
This paper describes a study of exposed anchors in shear such as those in a typical column footing connection with a grout leveling pad. Two groups of double-shear tests of threaded rods (ASTM A193 Grade B7) were conducted along with finite element analyses to simulate the behaviour of exposed anchors in shear. The study indicated that the exposed length and boundary conditions of exposed anchors significantly affects the load-carrying capacities and the corresponding failure modes because the anchors are subjected to combined bending, shear, and tension. Design equations were proposed for exposed anchors based on the experimental and numerical results.

]]> 10.1504/IJTAMM.2011.043534 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 111 - 129 Zhibin Lin; Derek Petersen; Jian Zhao; Ying Tian Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA. ' Osmose Railroad Services Inc., Madison, WI 53716, USA. ' Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA. ' Department of Civil and Environmental Engineering, University of Nevada, Las Vegas, NV 89154, USA concrete anchors anchor connections fastening to concrete composite construction exposed anchor bolts shear tests design threaded rods finite element analysis FEA simulation load carrying failure modes bending tension. 2011-11-04T23:20:50-05:00 2 2 111 129 2011-11-04T23:20:50-05:00 http://www.inderscience.com/link.php?id=43535 Viscous contribution for the Viscous Potential Flow (VPF) analysis of capillary instability with axial electric field at the interface of two viscous fluids has been analysed. In VPF, viscosity enters through normal stress balance and the effects of shearing stresses are completely ignored. To include the effect of shearing stresses, viscous pressure is included in normal stress balance along with irrotational pressure and it is assumed that the viscous contribution to the irrotational pressure will resolve the discrepancy between the tangential stresses at the interface. Stability criterion is given in terms of critical value of electric field. Various graphs have been drawn to show the effect of the parameters, such as electric field, inner fluid fraction, Ohnesorge number, conductivity ratio and permittivity ratio. Viscous contribution to the pressure for electroviscous potential flow analysis of capillary instability
M.K. Awasthi; G.S. Agrawal
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 130 - 145
Viscous contribution for the Viscous Potential Flow (VPF) analysis of capillary instability with axial electric field at the interface of two viscous fluids has been analysed. In VPF, viscosity enters through normal stress balance and the effects of shearing stresses are completely ignored. To include the effect of shearing stresses, viscous pressure is included in normal stress balance along with irrotational pressure and it is assumed that the viscous contribution to the irrotational pressure will resolve the discrepancy between the tangential stresses at the interface. Stability criterion is given in terms of critical value of electric field. Various graphs have been drawn to show the effect of the parameters, such as electric field, inner fluid fraction, Ohnesorge number, conductivity ratio and permittivity ratio.

]]> 10.1504/IJTAMM.2011.043535 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 130 - 145 M.K. Awasthi; G.S. Agrawal Department of Mathematics, Indian Institute of Technology Roorkee, Roorkee 247667, India. ' Department of Mathematics, Indian Institute of Technology Roorkee, Roorkee 247667, India viscous contribution viscous potential flow capillary instability interfacial flows axial electric field electroviscous flow viscous fluids viscosity shearing stress. 2011-11-04T23:20:50-05:00 2 2 130 145 2011-11-04T23:20:50-05:00 http://www.inderscience.com/link.php?id=43536 An extensive numerical analysis was conducted to investigate the nonlinear buckling of built-up cold-formed sections. This paper presents the calibration of nonlinear finite element models to handle nonlinear buckling behaviour of cold-formed steel sections with geometrically unstable configurations. The two nonlinear finite element packages ANSYS and ABAQUS were used to validate 265 experimental tests. Two different numerical schemes (implicit static and explicit dynamic) under various iterative and non-iterative solution techniques, including Newton-Raphson, Arc-Length, Riks, and Central-Difference integration methods, were adopted to produce reliable solutions. Overall, the numerical analysis estimated the experimental results reasonably well with an adjustment factor of 0.88. Nonlinear buckling of built-up cold-formed sections
Krisda Piyawat; Chris Ramseyer; Thomas H-K. Kang
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 146 - 164
An extensive numerical analysis was conducted to investigate the nonlinear buckling of built-up cold-formed sections. This paper presents the calibration of nonlinear finite element models to handle nonlinear buckling behaviour of cold-formed steel sections with geometrically unstable configurations. The two nonlinear finite element packages ANSYS and ABAQUS were used to validate 265 experimental tests. Two different numerical schemes (implicit static and explicit dynamic) under various iterative and non-iterative solution techniques, including Newton-Raphson, Arc-Length, Riks, and Central-Difference integration methods, were adopted to produce reliable solutions. Overall, the numerical analysis estimated the experimental results reasonably well with an adjustment factor of 0.88.

]]> 10.1504/IJTAMM.2011.043536 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 146 - 164 Krisda Piyawat; Chris Ramseyer; Thomas H-K. Kang Donald G. Fears Structural Engineering Laboratory, School of Civil Engineering and Environmental Science, The University of Oklahoma, Norman, OK 73019, USA. ' Donald G. Fears Structural Engineering Laboratory, School of Civil Engineering and Environmental Science, The University of Oklahoma, Norman, OK 73019, USA. ' Donald G. Fears Structural Engineering Laboratory, School of Civil Engineering and Environmental Science, The University of Oklahoma, Norman, OK 73019, USA nonlinear FEA finite element analysis axial load capacity distortional buckling built-up sections cold-formed steel sections cold forming modelling. 2011-11-04T23:20:50-05:00 2 2 146 164 2011-11-04T23:20:50-05:00 http://www.inderscience.com/link.php?id=43537 Surface charge density and distribution dependence of a nanochannel electro-osmotic flow was examined using a Molecular Dynamics (MD) model. Systems consisting of Na<SUP align=right>+</SUP> and Cl<SUP align=right>?</SUP> ions in water confined between crystalline walls with varying negative charge on inner surfaces in an external electric field were investigated. At low surface charge densities, water flows as expected by common interpretations of electro-osmosis. At intermediate surface charge density, the flow exhibits a maximum. Strongly charged surfaces cause adsorption of counterions, immobilisation of the near-wall fluid layers, and subsequent flow reversal. An effect of increase in the viscosity of water near the strongly charged surface was demonstrated. When the discrete 1 e charge was distributed on a subgrid of surface atoms, the flow deteriorated and reversed at much lower surface charge densities than when all the surface atoms carried equal partial charge. Effects of surface charge density and distribution on the nanochannel electro-osmotic flow
Bohumir Jelinek; Sergio D. Felicelli; Paul F. Mlakar; John F. Peters
International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 165 - 183
Surface charge density and distribution dependence of a nanochannel electro-osmotic flow was examined using a Molecular Dynamics (MD) model. Systems consisting of Na<SUP align=right>+</SUP> and Cl<SUP align=right>?</SUP> ions in water confined between crystalline walls with varying negative charge on inner surfaces in an external electric field were investigated. At low surface charge densities, water flows as expected by common interpretations of electro-osmosis. At intermediate surface charge density, the flow exhibits a maximum. Strongly charged surfaces cause adsorption of counterions, immobilisation of the near-wall fluid layers, and subsequent flow reversal. An effect of increase in the viscosity of water near the strongly charged surface was demonstrated. When the discrete 1 e charge was distributed on a subgrid of surface atoms, the flow deteriorated and reversed at much lower surface charge densities than when all the surface atoms carried equal partial charge.

]]> 10.1504/IJTAMM.2011.043537 International Journal of Theoretical and Applied Multiscale Mechanics, Vol. 2, No. 2 (2011) pp. 165 - 183 Bohumir Jelinek; Sergio D. Felicelli; Paul F. Mlakar; John F. Peters Center for Advanced Vehicular Systems, Mississippi State University, 200 Research Boulevard, Starkville, Mississippi 39759, USA. ' Mechanical Engineering Department, Mississippi State University, Mail Stop 9552, 210 Carpenter Building, Mississippi State, Mississippi 39762, USA. ' US Army ERDC, 3909 Halls Ferry Rd., Vicksburg, Mississippi 39180, USA. ' US Army ERDC, 3909 Halls Ferry Rd., Vicksburg, Mississippi 39180, USA nanochannels electrokinetic ?ow electro-osmosis ?ow reversal surface charge charge density charge distribution density effects viscosity molecular dynamics. 2011-11-04T23:20:50-05:00 2 2 165 183 2011-11-04T23:20:50-05:00