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 Hencky’s 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

Matlab parallel codes for 3D slope stability benchmarks

This contribution is focused on a description of implementation details for solver related to the slope stability benchmarks in 3D. Such problems are formulated by the standard elastoplastic models containing the Mohr-Coulomb yield criterion and by the limit analysis of collapse states. The implicit Euler method and higher order finite elements are used for discretization. The discretized problem is solved by non-smooth Newton-like methods in combination with incremental methods of limit load analysis. In this standard approach, we propose several innovative techniques. Firstly, we use recently developed sub-differential based constitutive solution schemes. Such an approach is suitable for non-smooth yield criteria, and leads better return-mapping algorithms. For example, a priori decision criteria for each return-type or simplified construction of consistent tangent operators are applied. The parallel codes are developed in MATLAB using Parallel Computing Toolbox. For parallel implementation of linear systems, we use the TFETI domain decomposition method. It is a non-overlapping method where the Lagrange multipliers are used to enforce continuity on the subdomain interfaces and satisfaction of the Dirichlet boundary conditions

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 Hencky’s material model with the von Mises criterion are considered. Here we describe some implementation details and present several numerical examples

A wind model for an elevated STOL-port configuration

Measurements of mean velocity magnitude and direction as well as three-dimensional turbulence intensity were made in the flow over a model of an elevated STOL-port. A 1:300 scale model was placed in a wind tunnel flow simulating the mean velocity profile and turbulence characteristics of atmospheric winds over a typical city environment excluding detailed wake structures of possible nearby buildings. Hot-wire anemometer measurements of velocity and turbulence were made along approach and departure paths of aircraft operating on the runway centerline and at specified lateral distances from the centerline. Approach flow directions simulated were 0 and 30 degrees to the runway centerline

SOFOS - A new Satellite-based Operational Fog Observation Scheme

This thesis introduces a new technique for the operational observation of fog from space. The scheme presented uses the Meteosat-8 SEVIRI system for near-real-time detection of low stratus and ground fog areas