8,361 research outputs found
Numerical solution of perfect plastic problems with contact: part II - numerical realization
This contribution is a continuation of our contribution denoted as PART I, where the discretized contact problem for elasto-perfectly plastic bodies was studied and suitable numerical methods were introduced. In particular, frictionless contact boundary conditions and Henckyâs material model with the von Mises criterion are considered. Here we describe some implementation details and present several numerical examples
A simple and efficient BEM implementation of quasistatic linear visco-elasticity
A simple, yet efficient procedure to solve quasistatic problems of special
linear visco-elastic solids at small strains with equal rheological response in
all tensorial components, utilizing boundary element method (BEM), is
introduced. This procedure is based on the implicit discretisation in time (the
so-called Rothe method) combined with a simple "algebraic" transformation of
variables, leading to a numerically stable procedure (proved explicitly by
discrete energy estimates), which can be easily implemented in a BEM code to
solve initial-boundary value visco-elastic problems by using the Kelvin
elastostatic fundamental solution only. It is worth mentioning that no inverse
Laplace transform is required here. The formulation is straightforward for both
2D and 3D problems involving unilateral frictionless contact. Although the
focus is to the simplest Kelvin-Voigt rheology, a generalization to Maxwell,
Boltzmann, Jeffreys, and Burgers rheologies is proposed, discussed, and
implemented in the BEM code too. A few 2D and 3D initial-boundary value
problems, one of them with unilateral frictionless contact, are solved
numerically
An adaptive hierarchical domain decomposition method for parallel contact dynamics simulations of granular materials
A fully parallel version of the contact dynamics (CD) method is presented in
this paper. For large enough systems, 100% efficiency has been demonstrated for
up to 256 processors using a hierarchical domain decomposition with dynamic
load balancing. The iterative scheme to calculate the contact forces is left
domain-wise sequential, with data exchange after each iteration step, which
ensures its stability. The number of additional iterations required for
convergence by the partially parallel updates at the domain boundaries becomes
negligible with increasing number of particles, which allows for an effective
parallelization. Compared to the sequential implementation, we found no
influence of the parallelization on simulation results.Comment: 19 pages, 15 figures, published in Journal of Computational Physics
(2011
Numerical solution of perfect plastic problems with contact: part I - theory and numerical methods
The contribution deals with a static case of discretized elasto-perfectly plastic problems obeying Henckyâs law in combination with frictionless contact boundary conditions. The main interest is focused on the analysis of the formulation in terms of displacements, limit load analysis and related numerical methods. This covers the study of: i) the dependence of the solution set on the loading parameter ζ, ii) relation between ζ and the parameter α representing the work of external forces, iii) loading process controlled by ζ and by α, iv) numerical methods for solving problems with prescribed value of ζ and α
A coupled finite-volume CFD solver for two-dimensional elasto-hydrodynamic lubrication problems with particular application to rolling element bearings
This paper describes a new computational fluid dynamics methodology for modelling elastohydrodynamic contacts. A finite-volume technique is implemented in the âOpenFOAMâ package to solve the Navier-Stokes equations and resolve all gradients in a lubricated rolling-sliding contact. The method fully accounts for fluid-solid interactions and is stable over a wide range of contact conditions, including pressures representative of practical rolling bearing and gear applications. The elastic deformation of the solid, fluid cavitation and compressibility, as well as thermal effects are accounted for. Results are presented for rolling-sliding line contacts of an elastic cylinder on a rigid flat to validate the model predictions, illustrate its capabilities, and identify some example conditions under which the traditional Reynolds-based predictions deviate from the full CFD solution
An adaptive mesh refinement approach for solving nonHertzian elastic contact problems
Semi-analytical methods are a common
way of solving non-hertzian contact problems when
designing mechanical components. These methods
require of the discretization of the domain into a set of
pressure elements and their accuracy and computational
cost are related to the number of elements in
which the domain is discretized. But, while the
accuracy increases as the pressure element mesh is
refined, the computational cost increases quadratically
with the number of pressure elements. So in the great
majority of the cases, a commitment between accuracy
and computational cost must be achieved. In this work,
a new approach has been developed to improve the
performance of semi-analytical methods for solving
contact problems. This approach uses an adaptive
mesh refinement strategy, based on the quadtree
decomposition of the domain. As a result, the computational
cost decreases, while the accuracy of the
method remains constant
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