Issue 53

Y. Saadallah, Frattura ed Integrità Strutturale, 53(2020) 417-425; DOI: 10.3221/IGF-ESIS.53.32 417 Modeling of mechanical behavior of cork in compression Younès Saadallah University of Mohamed Seddik Ben Yahia, Jijel, Algeria sayounes@live.fr, http://orcid.org/0000-0003-1265-3677 A BSTRACT . The present work consists of a contribution in modeling the mechanical behavior of cork in compression. For this purpose, compression tests are performed in the non-radial direction on high density reproduction cork samples. Cork shows stress-strain curves, typical of cellular materials, characterized by an elastic slope followed by an important plateau corresponding to buckling of cells; and finally hardening due to the densification of the material. Two behavior models are proposed to represent this behavior. A trilinear model in which each slope represents one of the three domains and whose parameters are identified directly from the stress- strain curves. A more nonlinear model corresponding to a third-order polynomial whose parameters are identified by means of a polynomial regression. Test-model comparisons reveal little relevance of the results given by the trilinear model whereas a very good consistency is observed for the results given by the nonlinear model. K EYWORDS . Cork; Compression; Behavior model; Parameters identification; Stress-strain. Citation: Saadallah, Y., Modeling of mechanical behavior of cork in compression, Frattura ed Integrità Strutturale, 53 (2020) 417-425 Received: 13.05.2020 Accepted: 02.06.2020 Published: 01.07.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION hoosing the right materials to use to perform specific functions is always a very important step. Different criteria are then taken into account, including cost and properties; but also, their impact on the environment. Environmental protection has become a major issue in recent times, it is extremely vital to look for ecological materials. Among these are natural materials including wood and cork. Cork is a natural product obtained from the outer bark of an oak species, the cork oak. The cork layers that are produced in its bark form a continuous envelope with appreciable thickness around the trunk and branches. The cork can be removed from the stem without endangering the vitality of the tree, which then rebuilds a new layer of cork. This is the basis of sustainable cork production during the long life of cork oak [1]. Lightness, high compressibility, dimensional recovery, thermal and sound insulation, very low permeability to liquids and gases and chemical stability are properties that make cork a widely used material in various applications [2-6]. The cost of this material is also an attractive factor. These so particular properties, still little explained, strongly encourage further research. The elastic properties of cork have been studied by several researchers. Gibson et al [5] focused on the identification of elastic parameters in the three radial, axial and tangential directions. The elastic modulus, the shear modulus and the C