In this paper, a positive definite semi-discrete mixed finite element method was presented for two-dimensional parabolic equations. In the new positive definite systems, the gradient equation and flux equations were separated from their scalar unknown equations.  Also, the existence and uniqueness of the semi-discrete mixed finite element solutions were proven. Error estimates were also obtaine...

We compute general (non-radial) positive solutions of the semi-linear elliptic PDE u + u + u 5 = 0, in 3 space dimensions (where the nonlinearity is critical) using the Finite Element Method. We have overcome two fundamental diiculties in this approach. Firstly the convergence of the numerical solutions is very slow (on regular grids) and it is necessary to work with very ne meshes (10 6 nodes)...

static analysis of sandwich constructions subjected to pressure and concentrated loads with the use of finite element method has been discussed in this paper. because of difficulties involved in analytical solution for most of the practical problems. an efficient computer programs has been developed that can be executed on a pc/xt computer and solves complicated problems easily and economically...

Abstract—This paper presents new semi-analytical expressions to calculate the self-inductance and the electromagnetic force for a ferromagnetic cylinder of finite length placed inside a circular coil of rectangular cross section. The proposed analytical model is based on boundary value problems with Fourier analysis. Laplace’s and Poisson’s equations are solved in each region by using the separ...

A general approach is proposed for the accurate and efficient computation of the characteristic parameters of coplanar waveguides having electrodes of complex cross-section on multi-layered, planar or non-planar substrates, as presently considered for high-speed (semiconductor or LiNbO3) electrooptic modulators. The approach is based on the coupling of quasi-TEM finite element method with numer...

deformation length is one of the most important parameters in cold roll-forming process, which plays a fundamental role in determining the inter-distance between the stations and rate of deformation. deformation length was first introduced by bhattacharyya. he also obtained a closed-form relation for this length in roll-forming of symmetric channel section. in this paper, deformation length in ...

S. A. Aksenov, E. N. Chumachenko, I. V. Logashina, Higher School of Economics, Department of Mechanics and Mathematical Simulation, Moscow, Russia T. Kubina, VŠB – Technical University of Ostrava, Faculty of Metallurgy and Materials Engineering, Ostrava, Czech Republic The application of finite element simulation to the problem of roll pass design for round bar rolling is considered. Two roll p...

This paper presents a simple method based on strain energy density criterion to study the crack initiation angle by finite element method under biaxial loading condition. The crack surface relative displacement method is used to eliminate the calculation of the stress intensity factors which are normally required. The analysis is performed using higher order four node quadrilateral element. The...