1,721,045 research outputs found
A 2D Cosserat finite element based on a damage-plastic model for brittle materials
No full textA 2D Cosserat model with a damage-plastic isotropic constitutive law for brittle-like materials is presented. Different damaging mechanisms in tension and compression are considered. The plastic flow is described by introducing a suitable yield function and evolution laws in terms of effective stresses. Small strain and displacement assumptions hold. A 4-node finite element is formulated with three degrees-of-freedom for each node and a predictor–corrector procedure is used to solve the damage-plastic evolutionary problem. The lateral response of walls under monotonic and cyclic horizontal actions is analyzed and a satisfactory description of the global response curves and damaging mechanisms is obtained
A multi-scale procedure for regular masonry based on a Cosserat-Cauchy nonlinear homogenization
No full textA REGULARIZED BEAM FINITE ELEMENT BASED ON A DAMAGE-PLASTIC MODEL FOR THE ANALYSIS OF R-C FRAMES
No full textIn this paper a new beam finite element is presented, for the analysis of the cyclic response of
reinforced concrete frames under static and dynamical loadings. A generalized section
constitutive law is proposed, based on a damage-plastic model, describing the damaging
process of the brittle cementitious matrix and the ductile behavior of the reinforcements. The
beam element is formulated via a force-based approach, so that the equilibrium along the
element is always satisfied. Furthermore, a simple regularization technique is proposed to
overcome the localization problems connected with the softening constitutive behavior, and in
order to obtain objective numerical results. A numerical solution algorithm, based on an
iterative element state determination and a predictor-corrector procedure at the section level,
is developed and some numerical applications are presented
A lumped plasticity equivalent beam model for the pushover analysis of masonry buildings
No full textA Cosserat multiscale model for damaged regular masonry walls
No full textA multiscale model for the structural analysis of the in-plane response of periodic masonry panels is presented, adopting at the macroscopic level the Cosserat micropolar continuum. At the microscopic scale, the classical Cauchy model is employed and a plastic-damage constitutive law is introduced. The nonlinear homogenization is performed employing the Transformation Field Analysis (TFA) technique. A numerical procedure is developed and implemented in a Finite Element (FE) code in order to analyze masonry structural problems
A regularized force-based beam element with a damage-plastic section constitutive law
No full textA new beam finite element is presented, with a generalized section constitutive law based on damage mechanics and plasticity, to analyse the cyclic structural response of plane frames. Both displacement-based and force-based (FB) approaches are used and compared, to demonstrate the significant advantages of the FB formulation in the presence of material non-linearity. In order to overcome the analytical problems and the pathological mesh dependency of the numerical response in the presence of strain-softening post-peak behaviour, a classical non-local regularization procedure is adopted first, based on the integral definition of the associated variable governing the damaging evolution process. Subsequently, for the FB element a new simple regularization technique is proposed based on a selected integration procedure along the element length, which predefines the location of the Gauss points in the beam region, where the localization phenomena take place. As for the other computational aspects, an iterative element state determination is adopted for the FB formulation and a local predictor–corrector algorithm is used to solve the incremental evolution problems of the damage and plastic internal variables. Finally, some examples are shown on simple beams and frames, subjected to monotonically increasing and cyclic loading conditions. Copyright © 2006 John Wiley & Sons, Ltd
Strength domains and return algorithm for the lumped plasticity equivalent frame model of masonry structures
No full textThe equivalent frame model for the assessment of in-plane mechanisms of masonry walls can be suitably based on a 2-node force-based finite element (FE) consisting of a central linear elastic element, two flexural hinges and a shear link with elastic-perfectly plastic behavior. The hinge state is determined by a predictor-corrector method. The predictor calculates the element stress field using the tangent flexibility matrix. The corrector consists of a return algorithm based on the Haar-Kármán principle and the gradient projection method, both leading to good convergence properties and to optimality characteristics of the solution
A beam finite element based on damage mechanics for dynamical structural analyses
No full textMunich, Germany,
Balkema Publ. Londo
A regularized force-based beam element with a plastic-damage section model
No full textlaw, to analyze the cyclic structural response of plane frames. Both displacement-based and forcebased
approaches are used and compared, to demonstrate the significant advantages of the force-based
formulation in the presence of material non-linearity. In order to overcome the pathological mesh
dependent behaviour due to strain-softening, a classical non-local regularization procedure is adopted
first, based on the integral definition of the associated variable governing the damaging process.
Subsequently, for the force-based element, a new simple regularization technique is proposed based on
a selected integration procedure along the element length, which predefines the location of the Gauss
points in the beam region where the localization phenomena take place. As for the other computational
aspects, an iterative element state determination is adopted for the force-based formulation and a local
predictor-corrector algorithm is used to solve the incremental evolution problems of the plasticity and
damage internal variables. Finally, some examples are shown on simple beams and frames, subjected
to monotonic and cyclic loading conditions
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