Effect of quality, porosity and density on the compression properties of cork

Anjos, Ofélia; Pereira, Helena; Rosa, M. Emília

doi:10.1007/s00107-008-0248-2

Cited by 66 publications

(53 citation statements)

References 12 publications

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“…This behaviour is common to cellular materials and follows the previously described tensile behaviour of cork Fortes 1991, Gibson andAshby 1997). Cork has substantially higher elastic resistance in tensile that in compression (Anjos et al 2008;Gibson and Ashby 1997). This difference can be explained because the cork cell walls are undulated plates (Pereira et al 1987, Gibson et al 1981.and the stiffness of undulated plates increases when the amplitude of the undulations decreases Therefore, in compression the walls bend and increase the cell wall corrugation, while in tension the cells are stretched and the cell wall undulations decrease (Anjos et al 2008, Rosa andFortes 1991).…”

Section: Resultsmentioning

confidence: 99%

“…The cork tissue may also contain occasional defects such as spots of sclerenchymatic cells with thick lignified walls, or inclusions of phloemic tissues, as well as tissue failures making up radial running hollow channels. In compression, the properties of cork were found to vary with density, cellular dimensions and porosity (Gibson and Ashby 1997, Pereira et al 1992, Anjos et al 2008. The influence of these effects was not studied in relation to the tensile properties.…”

Section: Introductionmentioning

confidence: 99%

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Tensile properties of cork in axial stress and influence of porosity, density, quality and radial position in the plank

Anjos

Pereira²,

Rosa

2010

Eur. J. Wood Prod.

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The behaviour of cork under tensile stress in the axial direction was studied for samples taken from cork planks of good (class 1) and poor (class 4) quality grades and at three radial positions within the plank (inner, mid and outer positions). The effect of cork density (ranging from 0.123 to 0.203 g.cm -3) and porosity (ranging from 2.8 to 9.6% in the tangential surface) on Young's modulus and fracture stress and strain was studied. The tensile stress-strain curves of cork showed an elastic deformation up to 2% strain with a Young's modulus of 30.8 MPa, and a fracture stress of 1.05 MPa at a strain of 7.1% for class1, and Young's modulus of 26.1 MPa, and a fracture stress of 0.77 MPa at a strain of 5.5 % for class 4. Fracture always started at a pore. The quality class and the radial position in the plank were highly significant factors of the tensile properties variation with good quality cork in the inner part of the plank showing the highest strength. Density influenced the elastic behaviour of cork with a highly significant correlation of increasing E with density, but not so clearly the fracture stress and strain. The variability of tensile properties with porosity was large and although significant, the correlations were lower in spite of a decreasing trend of E with porosity. Fracture depended on the type of defects in cork. Zugfestigkeitseigenschaften von Kork in axialer

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tensile properties of cork in axial stress and influence of porosity, density, quality and radial position in the plank

Anjos

Pereira²,

Rosa

2010

Eur. J. Wood Prod.

Self Cite

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“…However, many researchers have extensively studied the fundamental aspects of cork's mechanical behavior under quasi-static axial compressive loading [20][21][22][23][24][25][26][27]. More recently, and regarding agglomerated cork (details on how agglomerated cork is produced can be found in [28]), the influence of cork density on cork's mechanical behavior under compression, as well as the subsequent recovery of dimensions were studied by Anjos et al [29].…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Comparing the mechanical performance of synthetic and natural cellular materials

et al. 2015

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a b s t r a c tThis work compares the mechanical performance of agglomerated cork against synthetic materials typically used as impact energy absorbers. Particularly, the study will focus on the expanded polystyrene (EPS) and expanded polypropylene (EPP).Firstly, quasi-static compression tests are performed in order to assess the energy storage capacity and to characterize the stress-strain behavior cellular materials under study. Secondly, guided drop tests are performed to study the response of these materials when subjected to multiple dynamic loading (two impacts). Thirdly, finite element analysis (FEA) is carried out in order to simulate the compressive behavior of the studied materials under dynamic loading.Results show that agglomerated cork is an excellent alternative to the synthetic materials. Not only for being a natural and sustainable material but also for withstanding considerable impact energies. In addition, its capacity to keep some of its initial properties after loading (regarding mechanical properties and dimensions) makes this material highly desirable for multiple-impact applications.

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“…Research on the mechanical behaviour of agglomerated cork is limited to a relatively small number of studies on static compression, tension, shear, bending, and creep, either alone [9][10][11], as a sandwich-core structure [12][13][14], ,or asa filler of a tubular structure [15,16].…”

Section: Introductionmentioning

confidence: 99%

“…This behaviour M a n u s c r i p t ends when the cells completely collapse, from which point a sharp increase in stress related to densification of the material occurs. This behaviour is strongly influenced by the density [9,17,20]. However, the forces that arise during a collision are dynamic, making it necessary to evaluate the behaviour of agglomerated cork under these conditions.…”

Section: Introductionmentioning

confidence: 99%

Dynamic crushing behaviour of agglomerated cork

Sánchez-Sáez

García-Castillo

Barbero

et al. 2015

Materials & Design (1980-2015)

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-For reasons of energy saving and pollution reduction, there is a growing interest in the development of lightweight structures manufactured with materials of natural origin and recyclable. Agglomerated cork is a mixture of natural cork and an organic binder, and can be considered an alternative to polymeric foams used in structural applications with a high capacity of energy absorption. One of these applications involves impact-absorbing elements in vehicles, which are subjected mainly to dynamic compressive loads. In this work, the dynamic crushing behaviour of agglomerated cork was experimentally studied, analysing the influence of the specimen thickness on the energy-absorption capacity, contact force, displacement, and strain. Dynamic crushing tests with specimens of four different thicknesses were performed in a drop-weight tower. An increase in the maximum contact force, displacement, and strain was observed when the impact-energy/thickness ratio increased. For each specimen thickness a linear variation of the maximum displacement and energy absorbed with the impact-energy/thickness ratio was found. It was observed that the energy absorbed by agglomerated cork did not depend on the specimen thickness, but only on the impact energy.

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Effect of quality, porosity and density on the compression properties of cork

Cited by 66 publications

References 12 publications

Tensile properties of cork in axial stress and influence of porosity, density, quality and radial position in the plank

Tensile properties of cork in axial stress and influence of porosity, density, quality and radial position in the plank

Comparing the mechanical performance of synthetic and natural cellular materials

Dynamic crushing behaviour of agglomerated cork

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