A computational framework for constitutive modelling

J Braz. Soc. Mech. Sci. Eng.

et al. 2020

Self Cite

The nonlinear modelling of concrete structures demands strain-softening models that correctly represent the nucleation and propagation of damage. The typical concentration of such degrading phenomena in limited parts of the structure results in the strain localization that can be highly affected by the numerical algorithm used to solve the softening behaviour in concrete material. Finite Element discretization based on models from the continuum damage mechanics has not been able to overcome the numerical localization induced, anticipating the failure of the analysed problem. The Generalized/eXtended Finite Element Method is investigated here as an alternative to the standard Finite Element Method aiming to efficiently simulate the concrete strain-softening phenomenon. The enrichment strategy of the G/XFEM is used to obtain the nonlinear structural response using coarse meshes combined with different constitutive models from the continuum damage mechanics. Experimental results available in the literature are numerically reproduced and compared with equivalent approaches using FEM. Pathological behaviours that affect the quality of the results are evaluated. The possibility of using several combinations of different numerical methods and constitutive models is ensured by a framework for computational mechanics that encloses the G/XFEM implementation.

Section: A Computational System To Physically Nonlinear Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Damage propagation using novel G/XFEM strategies: computational aspects and numerical investigations

Wolenski

Monteiro

J Braz. Soc. Mech. Sci. Eng.

et al. 2020

Self Cite

“…Association between the plans of discontinuities and the solid concrete microstructure Leukart [6] proposition, in order to allow any microplane equivalent strain measure and any damage law. Such an improvement has been implemented in the context of the Unified Computational Environment, proposed by Penna [12] and Gori et al [13], on the IN-SANE. This system has been expanded by Alves et al [14] with the enclosing the standard version of GFEM formulation with minimum impact in the code structure.…”

Section: Figurementioning

confidence: 99%

Nonlinear analysis of concrete structures using GFEM enrichment strategy with a microplane constitutive model

Wolenski¹,

Monteiro

Rev. IBRACON Estrut. Mater.

et al. 2018

One of the most widespread methods to the nonlinear analysis of structures is the Finite Element Method (FEM). However, there are phenomena whose behavior is not satisfactorily simulated by the standard FEM and this fact has quickened the development of new strategies such as the Generalized Finite Element Method (GFEM), understood as a variation of the FEM. In parallel, nonlinear analysis of concrete structures requires the use of constitutive models that represents the nucleation and propagation of cracks. In this paper it is used an anisotropic constitutive model, based on the microplane theory, which is able to represent the behavior of concrete structures, together with the GFEM approach. These resources are incorporated on the INSANE system (INteractive Structural ANalysis Environment), used in the numerical simulations presented here to demonstrate the feasibility of using the GFEM enrichment strategy, in the nonlinear analysis of concrete structures, with validation made from comparisons with experimental results available in the literature.

“…From a theoretical point of view, the generality of the representation is guaranteed by the tensorial formalism of the involved constitutive equations, as illustrated by Rizzi and Carol [33]. Taking into account these concepts, the authors have recently proposed a framework for constitutive models for classic media based on the Object-Oriented Paradigm (OOP) [34], and implemented in the open-source software INSANE 1 (INteractive Structural ANalysis Environment) [35]. The result was a computational resource that has been showed to be highly modular and easy to expand, independent on the different numerical methods, and independent on the different analysis models.…”

Section: Introductionmentioning

confidence: 99%

A computational framework for the constitutive modeling of nonlinear micropolar media

Gori

J Braz. Soc. Mech. Sci. Eng.

Pitangueira

2019

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Despite the large number of applications with micropolar models, the aspects of their implementation have been rarely addressed in the literature. In the present paper, a strategy for the computational modeling of micropolar media with elastoplasticity and elastic degradation is investigated. The proposed strategy is based on the Object-Oriented Paradigm (OOP) and on the use of tensor objects. The presence of tensor objects inside the code allows to obtain a constitutive models framework that, with respect to existent implementations, is independent on both the adopted analysis model and numerical method. The OOP, with its properties of abstraction, inheritance, and polymorphism, leads to a framework highly modular and easy to expand. The theoretical basis is a compact tensorial representation for the micropolar equations that makes them formally identical to the ones of the classic continuum theory. This compatibility has been here extended to their computational expressions, making possible to use the same code structure for both the continuum models, taking advantage of existing implementations of classic constitutive models.