T. Jarak¹, J. Sorić¹, J. Hoster¹

CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.3, pp. 235-246, 2007, DOI:10.3970/cmes.2007.018.235

Abstract A meshless computational method based on the local Petrov-Galerkin approach for the analysis of shell structures is presented. A concept of a three dimensional solid, allowing the use of completely 3-D constitutive models, is applied. Discretization is carried out by using both a moving least square approximation and polynomial functions. The exact shell geometry can be described. Thickness locking is eliminated by using a hierarchical quadratic approximation over the thickness. The shear locking phenomena in case of thin structures and the sensitivity to rigid body motions are minimized by applying interpolation functions of sufficiently high order. The numerical efficiency of… 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 using the Structured Adaptive Mesh… More >

J. Sladek¹, V. Sladek¹, S.N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.3, pp. 309-318, 2004, DOI:10.3970/cmes.2004.006.309

Abstract Meshless methods based on the local Petrov-Galerkin approach are proposed for solution of steady and transient heat conduction problem in a continuously nonhomogeneous anisotropic medium. Fundamental solution of the governing partial differential equations and the Heaviside step function are used as the test functions in the local weak form. It is leading to derive local boundary integral equations which are given in the Laplace transform domain. The analyzed domain is covered by small subdomains with a simple geometry. To eliminate the number of unknowns on artificial boundaries of subdomains the modified fundamental solution and/or the parametrix with a convenient cut-off… More >

Q. Li¹, S. Shen¹, Z. D. Han¹, S. N. Atluri¹

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.5, pp. 571-586, 2003, DOI:10.3970/cmes.2003.004.571

Abstract In this paper, a truly meshless method, the Meshless Local Petrov-Galerkin (MLPG) Method, is developed for three-dimensional elasto-statics. The two simplest members of MLPG family of methods, the MLPG type 5 and MLPG type 2, are combined, in order to reduce the computational requirements and to obtain high efficiency. The MLPG5 method is applied at the nodes inside the 3-D domain, so that any domain integration is eliminated altogether, if no body forces are involved. The MLPG 2 method is applied at the nodes that are on the boundaries, and on the interfaces of material discontinuities, so that the boundary… More >

D. Zupan¹, M. Saje¹

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.2, pp. 301-318, 2003, DOI:10.3970/cmes.2003.004.301

Abstract A new finite element formulation of the `kinematically exact finite-strain beam theory' is presented. The finite element formulation employs the generalized virtual work in which the main role is played by the pseudo-curvature vector. The solution of the governing equations is found by using a combined Galerkin-collocation algorithm. More >

K. Nesnas¹, A. Abdul-Latif²

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.3, pp. 373-388, 2001, DOI:10.3970/cmes.2001.002.373

Abstract Large plastic collapse of an identical pair of cylinders of various geometries having the same length and volume is studied under lateral compressive load. Superplastic material is employed as a representative material to simulate the classical engineering material behavior under high strain rate. The effects of the strain rate and the geometry of cylinders on the plastic collapse are taken into account. The experimental study is conducted using a structure in which one cylinder is superplastic and the other is steel (referred to as deformable and non-deformable situation "DND''). The actual structure (DND) and that one investigated experimentally by Abdul-Latif… More >

R. Vignjevic, T. De Vuyst, M. Gourma¹

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.3, pp. 319-336, 2001, DOI:10.3970/cmes.2001.002.319

Abstract The work presented provides an overview of different types of kernel interpolation used in the SPH method: conventional SPH, normalised SPH (NSPH), corrected kernel SPH (CSPH) and normalised corrected kernel SPH (NCSPH). These four methods are considered in a fully mesh-free form (using no background mesh). To illustrate the effect of using different interpolation methods two problems were simulated: a 1D symmetric elastic impact problem, and a shock-tube. An overview of the simulation results for the two problems is given. Shortcomings for the interpolation schemes tested were identified and discussed. It is concluded that NCSPH provides the best results. To… 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 at understanding the following… More >

Akira Hirata¹

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.3, pp. 203-230, 2007, DOI:10.3970/fdmp.2007.003.203

Abstract This article is a summary of author's typical research works (over the last four decades) on interphase transport phenomena in the presence of interfacial fluid motion and surface tension gradients on liquid-fluid interfaces, and related applications to single crystal growth and microgravity sciences. A unified theory for momentum, heat and mass transfer on liquid-fluid and solid-fluid interfaces is proposed, which takes into account interface mobility. It is shown that interface contamination and turbulence can be well explained, respectively, by suppression and enhancement of the interfacial velocity induced by surface tension gradients. Transport phenomena on solid spheres, liquid drops and gas… More >

B. Yang², V. K. Tewary³

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 23-32, 2008, DOI:10.3970/cmc.2008.008.023

Abstract A three-dimensional Green's function for a material system consisting of anisotropic and linearly elastic planar multilayers with interfacial membrane and flexural rigidities has been derived. The Stroh formalism and two-dimensional Fourier transforms are applied to derive the general solution for each homogeneous layer. The Green's function for the multilayers is then solved by imposing the surface boundary condition, the interfacial displacement continuity condition, and the interfacial traction discontinuity condition. The last condition is given by the membrane and bending equilibrium equations of the interphases modeled as Kirchhoff plates. Numerical results that demonstrate the validity and efficiency of the formulation are… More >