Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
Search Results
Conference Object Citation - Scopus: 2Crystal Plasticity Based Modelling of Shear Response of Carbon Fibre Reinforced Composites(Elsevier B.V., 2021) Özdemir, İzzet; Özdemir,I.; 01. Izmir Institute of Technology; 03.03. Department of Civil Engineering; 03. Faculty of EngineeringDue to their superior strength-to-weight performance, there is an increasing tendency to use carbon fibre reinforced composites (CFRP) in different engineering applications. Under transverse loading, the resulting stress-strain curve has a nonlinear character with significant hardening. As far as modelling of CFRP is concerned, the hardening behaviour is typically described by fitting curves to experimental data. Obviously, this route does not take deformation mechanisms at constituent level e.g. fibre rotation and matrix yielding, into account and leads to descriptive models rather than predictive ones. Such models yield poor predictions particularly for CFRP's with 3D microstructural architectures, which have achieved much higher ductility level and texture evolution as compared to conventional 2D architectures. In recent studies Meza et al. (2019), Tan and Liu (2020), motivated by the similarity between the shearing along slip planes and the plastic deformation of a tow, crystal plasticity is exploited to capture the evolution of the composite microstructure. This contribution focuses on the crystal plasticity inspired model of CFRP and its implementation within the commercial finite element software Abaqus through UEL subroutine. The predictions of the model are assessed by means of two example problems including combined loading scenarios. © 2021 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 IWPDF 2021 Chair, Tuncay YalçinkayaConference Object Citation - Scopus: 3Localizing Implicit Gradient Damage Based Treatment of Softening in Elasto-Plasticity(Elsevier B.V., 2021) Özdemir, İzzet; Kaçmaz,B.; Özdemir,I.; 01. Izmir Institute of Technology; 03.03. Department of Civil Engineering; 03. Faculty of EngineeringAs opposed to brittle fracture, the failure of ductile materials is preceded by severe plastic deformations. Microscopic mechanisms i.e., void growth and coalescence result in macroscopic property degradation causing softening, localization, and finally macroscopic crack. This contribution focuses on softening in elasto-plasticity and its mesh-objective description using an implicit gradient type of non-local damage mechanics framework. As reported in several studies Geers et al. (1998), Poh and Sun (2017), artificial widening of localization zone is observed when conventional implicit gradient type regularization is used. To circumvent this non-physical artifact, localizing implicit gradient damage (LIGD) formulation that is motivated by higher order continuum arguments, is adopted, Poh and Sun (2017). As opposed to previous remedies to artificial widening of the localization zone, LIGD proposes an internal length scale that decreases with deformation. A two-field (displacement-non-local equivalent plastic strain) hexahedra and a three-field (displacement-pressure-non-local equivalent plastic strain) tetrahedra element are formulated and implemented in commercial finite element software Abaqus through user element (UEL) subroutine. The effectiveness of the approach is demonstrated by solving two numerical examples. © 2021 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 IWPDF 2021 Chair, Tuncay Yalçinkaya