Search results for " SGBEM"
showing 9 items of 9 documents
SHAKEDOWN ANALYSIS BY BEM
2000
In the ambit of the symmetric Galerkin boundary element formulation the statical shakedown load multiplier and the limit analysis are reformulated making use of macrozone modelling. The subdivision of the domain into macroelements makes it possible to deal with piecewise homogeneous materials of the body. For each macroelement a discretization of the boundary and a subdivision of the domain into portions called cells are performed in order to introduce the unknowns (i.e. traction and displacement discontinuities) on the boundary and material plastic laws appropriately interpolated. The weighed regularity imposed between adjacent macroelements produces algebraic operators which are symmetric…
Elastoplastic analysis by active macro-zones with linear kinematic hardening and von Mises materials.
2014
In this paper a strategy to perform elastoplastic analysis with linear kinematic hardening for von Mises materials under plane strain conditions is shown. The proposed approach works with the Symmetric Galerkin Boundary Element Method applied to multidomain problems using a mixed variables approach, to obtain a more stringent solution. The elastoplastic analysis is carried out as the response to the loads and the plastic strains, the latter evaluated through the self-equilibrium stress matrix. This matrix is used both, in the predictor phase, for trial stress evaluation and, in the corrector phase, for solving a nonlinear global system which provides the elastoplastic solution of the active…
Multidomain Symmetric Galerkin BEM for non-linear analysis of masonries in-plane loaded
2014
The preservation of the historical and monumental buildings, but also of the considerable heritage of old constructions made by traditional techniques, is one of the actual problems of the structural mechanics. The level of knowledge of their structural behavior in presence of external actions is made through calculus methods and simple procedures in order to allow a reading of the material suffering degree and as a consequence of the related safety. In this paper an elastic analysis of walls, also in presence of geometrical nonlinearity consisting in the contact/detachment phenomenon among stone blocks. The wall having any shape and zone-wise variable physical characteristics is loaded in …
Frctionless contact: step by step analysis and mathematical programming technique
2011
The object of the paper concerns a consistent formulation of the classical Signorini's theory regarding the frictionless unilateral contact problem between two elastic bodies in the hypothesis of small displacements and strains. A variational approach employed in conjunction with the Symmetric Boundary Element Method (SBEM) leads to an algebraic formulation based on generalized quantities [1]. The contact problem is decomposed into two sub-problems: one is purely elastic, the other pertains to the unilateral contact conditions alone [2,3]. Following this methodology, the contact problem, by symmetric BEM, is characterized by symmetry and sign definiteness of the coefficient matrix, thus adm…
Characteristic matrix in the bending plate analysis by SBEM
2008
This paper deals with the thin bending plate analysis by using the symmetric approach of Boundary Element Method (SBEM). A formulation is used in which the plate boundary is discretized into boundary elements and is subjected to appropriate distributions of shear forces and couples, as well as of vertical displacement and rotations. These distributions are the causes and are modelled through appropriate shape functions, whereas the generalized effects are obtained, according to the Galerkin approach, as weighting of the displacements and the rotations, as well as of the shear forces and moments. In the equations system the algebraic operator is a symmetric matrix whose coefficients are defi…
Active macro-zone approach for incremental elastoplastic-contact analysis
2013
The symmetric boundary element method, based on the Galerkin hypotheses, has found an application in the nonlinear analysis of plasticity and in contact-detachment problems, but both dealt with separately. In this paper, we want to treat these complex phenomena together as a linear complementarity problem. A mixed variable multidomain approach is utilized in which the substructures are distinguished into macroelements, where elastic behavior is assumed, and bem-elements, where it is possible that plastic strains may occur. Elasticity equations are written for all the substructures, and regularity conditions in weighted (weak) form on the boundary sides and in the nodes (strong) between cont…
Incremental elastoplastic analysis for active macro-zones
2012
In this paper a strategy to perform incremental elastoplastic analysis using the symmetric Galerkin boundary element method for multidomain type problems is shown. The discretization of the body is performed through substructures, distinguishing the bem-elements characterizing the so-called active macro-zones, where the plastic consistency condition may be violated, and the macro-elements having elastic behaviour only. Incremental analysis uses the well-known concept of self-equilibrium stress field here shown in a discrete form through the introduction of the influence matrix (self-stress matrix). The nonlinear analysis does not use updating of the elastic response inside each plastic loop…