this research work is devoted to the development of a mathematical model for the simulation of the flow of polymeric melts through the die region of extruders. a set of governing equations are solved using finite element method. standard galerkin technique is used in conjunction with the mixed scheme to solve the flow equation. due to the non-linear nature of global equations, the picard iterat...

Finite element simulations in computational biomechanics commonly require the discretization of extremely complicated geometries. Creating meshes for these complex geometries can be very difficult and time consuming using hexahedral elements. Automatic meshing algorithms exist for tetrahedral elements, but these elements often have numerical problems that discourage their use in complex finite ...

This paper is devoted to the construction of nonconforming finite elements for the discretization of fourth order elliptic partial differential operators in three spatial dimensions. The newly constructed elements include two nonconforming tetrahedral finite elements and one quasi-conforming tetrahedral element. These elements are proved to be convergent for a model biharmonic equation in three...

A new algorithm for simulation of polymer coextrusion is introduced. In the new algorithm, the finite element mesh of tetrahedral elements remains unaltered as the interface shape between adjacent polymer layers is developed during the simulation. The use of a fixed finite element mesh for coextrusion simulation is possible because in the new algorithm the interface between the two polymers is ...

In this paper, we examine the numerical dispersion properties of the tetrahedral edge element in comparison to other edge and nodal elements. For all nodal elements as well as hexahedral edge elements, the phase error is always either positive or negative for waves propagating at any incidence angle, which means that the error accumulates as the wave propagates from element to element. This eff...

A new algorithm for simulation of non-isothermal flow in a twin-screw extruder is introduced. In the new algorithm, the finite element mesh of tetrahedral elements is created in the complete barrel including the space occupied by the screws. By partitioning the tetrahedral elements which are intersected by the screw surfaces into two tetrahedral, pyramidal or prismatic finite elements, the new ...

 The accuracy of finite element approximation on tetrahedral elements is studied using the previously derived maximum eigenvalue condition. This condition is linked with the minimum singular value of the element ‘edge shape matrix’ that characterizes the flatness of an element. A geometric interpretation of these results is discussed. From the theoretical viewpoint, a better insight into the m...

Automatic hexahedral mesh generation for complex geometries is still a challenging problem, and therefore tetrahedral or mixed meshes are preferred. Unfortunately the standard formulation of the linear tetrahedral element exhibits volumetric locking in case of almost incompressible materials. In this paper we propose a new linear tetrahedral element based on the average nodal Jacobian. This ele...

3D Hybrid Finite Element Finite Difference Time Domain (FE/FDTD) Method is developed and applied to the numerical modeling of antennas. The antenna geometry is modeled using tetrahedral finite element mesh. Pyramidal elements are introduced in the transition from unstructured tetrahedral elements to structured hexahedral elements. The finite element formulation incorporates the excitation of an...

In 1988, Worsey and Piper constructed a trivariate macro-element based on C quadratic splines defined over a split of a tetrahedron into 24 subtetrahedra. However, this local element can only be used to construct a corresponding macro-element spline space over tetrahedral partitions that satisfy some very restrictive geometric constraints. We show that by further refining their split, it is pos...