PSI - Issue 44

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ScienceDirect

Procedia Structural Integrity 44 (2023) 544–549 Structural Integrity Procedia 00 (2022) 000–000 Structural Integrity Procedia 00 (2022) 000–000

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© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy. Abstract Shell structures made of Reinforced Concrete (RC) are used in many civil engineering applications. However, their analysis can frequently require a high computational cost, since fine mesh discretisations are needed for accurate solutions. In this work, a Finite Element (FE) for the analysis of RC shells is presented. It has four nodes and 24 degrees of freedom and both generalised stresses and displacements are interpolated. In particular, the assumed stress field a-priori satisfies equilibrium equations, thereby ensuring good accuracy and convergence properties. The heterogeneous material is described through a layer-wise approach in which a 3D stress yield function is used for concrete. Results confirm that the proposed FE is accurate on coarse meshes and shows good convergence properties if compared with state-of-art alternatives. The approach can be readily extended to model additional material layers, for example reinforcements applied for retrofitting purposes. 2022 The Authors. Published by Elsevier B.V. is is an open access article under the CC BY-NC-ND license (http: // creativec mmons.org / licenses / by-nc-nd / 4.0 / ) r-review under responsibility of the scientific committe of the XIX ANIDIS Conf rence, Seismic Engineering in Italy. Keywords: mixed shell elements; plasticity; reinforced concrete Abstract Shell structures made of Reinforced Concrete (RC) are used in many civil engineering applications. However, their analysis can frequently require a high computational cost, since fine mesh discretisations are needed for accurate solutions. In this work, a Finite Element (FE) for the analysis of RC shells is presented. It has four nodes and 24 degrees of freedom and both generalised stresses and displacements are interpolated. In particular, the assumed stress field a-priori satisfies equilibrium equations, thereby ensuring good accuracy and convergence properties. The heterogeneous material is described through a layer-wise approach in which a 3D stress yield function is used for concrete. Results confirm that the proposed FE is accurate on coarse meshes and shows good convergence properties if compared with state-of-art alternatives. The approach can be readily extended to model additional material layers, for example reinforcements applied for retrofitting purposes. © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy. Keywords: mixed shell elements; plasticity; reinforced concrete XIX ANIDIS Conference, Seismic Engineering in Italy An e ffi cient elastoplastic model for the analysis of reinforced concrete shells Francesco S. Liguori a, ∗ , Antonella Corrado a , Antonio Bilotta a , Antonio Madeo a a Universita` della Calabria, Dipartimento di Ingegneria Informatica Elettronica Modellistica e Sistemistica, 87036 Rende (CS), Italy XIX ANIDIS Conference, Seismic Engineering in Italy An e ffi cient elastoplastic model for the analysis of reinforced concrete shells Francesco S. Liguori a, ∗ , Antonella Corrado a , Antonio Bilotta a , Antonio Madeo a a Universita` della Calabria, Dipartimento di Ingegneria Informatica Elettronica Modellistica e Sistemistica, 87036 Rende (CS), Italy In the solution of many engineering problems the nonlinear behaviour of structure due to the inelastic response of materials are often described using elastoplastic models which are capable to accurately simulate the behaviour of many kind of engineering materials, not only metals but also stone-like materials and soils, Jirasek and Bazant (2002). Moreover the complexity of the problem to be solved, involving highly nonlinear and nonsmooth elastoplastic constitutive equations, Simo and Hughes (1998), and the need for application of complex design rules, for example the application of several loading conditions with the check of di ff erent limit states, require the adoption of robust and very e ffi cient solution algorithms. In this work a finite element for the modelling of concrete flat shell embodying steel reinforcement bars is proposed. The element formulation is based on assumed stress and displacement field interpolations, a kind of formulation cer tainly enjoying the feature of providing high performance models as shown in Bilotta and Casciaro (2002) in the In the solution of many engineering problems the nonlinear behaviour of structure due to the inelastic response of materials are often described using elastoplastic models which are capable to accurately simulate the behaviour of many kind of engineering materials, not only metals but also stone-like materials and soils, Jirasek and Bazant (2002). Moreover the complexity of the problem to be solved, involving highly nonlinear and nonsmooth elastoplastic constitutive equations, Simo and Hughes (1998), and the need for application of complex design rules, for example the application of several loading conditions with the check of di ff erent limit states, require the adoption of robust and very e ffi cient solution algorithms. In this work a finite element for the modelling of concrete flat shell embodying steel reinforcement bars is proposed. The element formulation is based on assumed stress and displacement field interpolations, a kind of formulation cer tainly enjoying the feature of providing high performance models as shown in Bilotta and Casciaro (2002) in the 1. Introduction 1. Introduction

∗ Corresponding author. E-mail address: francesco.liguori@unical.it ∗ Corresponding author. E-mail address: francesco.liguori@unical.it

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy. 10.1016/j.prostr.2023.01.071 2210-7843 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review u der responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy. 2210-7843 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy.