In this paper, we present an analytical method to investigate the behavior of a two degrees of freedom oscillator excited by dry friction. The system consists of two masses connected by linear springs. These two masses are in contact with a driving belt moving at a constant velocity. The contact forces between the masses and the belt are obtained from Coulomb’s friction laws. A set of periodic ...

Numerical solution of extremely large and ill conditioned eigenvalue problems is attracting a growing attention recently as such problems are of major importance in applications. They arise typically as discretization of continuous models described by systems of partial differential equations (PDE’s). For such problems, preconditioned matrix-free eigensolvers are especially effective as the sti...

An iterative algorithm is adopted to construct approximate representations of matrices describing the scattering properties arbitrary objects. The method based on implicit evaluation responses from iteratively generated excitations. does not require explicit knowledge any system (e.g., stiffness or impedance matrices) and well-suited for use with matrix-free full-wave solvers, such as FDTD, FEM...

The boundary concentrated finite element method is a variant of the hp-version of the finite element method that is particularly suited for the numerical treatment of elliptic boundary value problems with smooth coefficients and low regularity boundary conditions. For this method we present two multilevel preconditioners that lead to preconditioned stiffness matrices with condition numbers that...

This paper is concerned with approximation properties of orthonormal mapped Chebyshev functions (OMCFs) in unbounded domains. Unlike the usual mapped Chebyshev functions which are associated with weighted Sobolev spaces, the OMCFs are associated with the usual (non-weighted) Sobolev spaces. This leads to particularly simple stiffness and mass matrices for higher-dimensional problems. The approx...

The consequences of rotational-symmetry breaking in Heisenberg spin-glasses are studied with use of order parameters which are time-dependent SO(3) rotation matrices. A microscopic derivation of the hydrodynamic "triad" theory, including the effect of small magnetic fields and random anisotropies, is presented. In the mean-field limit the finitetime exchange stiffness and macroscopic anisotropy...

Following some de Rham complex, Arnold and Winther have recently proposed a symmetric mixed finite element method (MFEM) in linear elasticity. This paper describes the implementation of the symmetric MFEM and its 30 30 local stress stiffness matrices and studies the implementation of the lowest-order scheme for general boundary conditions. Numerical experiments in model examples in computationa...

In this paper we present a layerwise finite element model for the analysis of sandwich laminated plates with a viscoelastic core and laminated anisotropic face layers. The stiffness and mass matrices of the element are obtained by the Carrera’s Unified formulation (CUF). The dynamic problem is solved in the frequency domain with viscoelastic frequency-dependent material properties for the core....

Cutaneous chronic wounds are characterized by an impaired wound healing which may lead to infection and amputation. When current treatments are not effective enough, the application of wound dressings is required. To date, no ideal biomaterial is available. In this study, highly dense collagen matrices have been evaluated as novel medicated wound dressings for the treatment of chronic wounds. F...

The boundary concentrated finite element method is a variant of the hp-version of the finite element method that is particularly suited for the numerical treatment of elliptic boundary value problems with smooth coefficients and low regularity boundary conditions. For this method we present two multilevel preconditioners that lead to preconditioned stiffness matrices with condition numbers that...