An Instrumented Macro-Indentation Method for Determining the Mechanical Properties of Coconut Shell (Coco Nucifera of Cameroon)

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E. Njeugna, M.B.K. Ganou, D. Ndapeu, J.N.T. Foba, N.R.T. Sikame & P.W.M. Huisken (2016). An Instrumented Macro-Indentation Method for Determining the Mechanical Properties of Coconut Shell (Coco Nucifera of Cameroon). Mechanics, Materials Science & Engineering, Vol 5. doi:10.13140/RG.2.1.1447.3846

Authors: E. Njeugna, M.B.K. Ganou, D. Ndapeu, J.N.T. Foba, N.R.T. Sikame, P.W.M. Huisken

ABSTRACT. An instrumented macro-indentation test was used to determine the viscoelastic parameters and hardness of the shell of Coco Nucifera from Cameroon in order to promote their use in the manufacture of abrasives. Samples measuring 10 mm x 10 mm x 3 mm were cut out from the bottom of the fruit, close to the natural indentations (the eye) of an approximately round-shaped fruit. The indentation load ranged from 50 to 500 N with an increment of 50 N. A comparator with digital display and a camera attached to the machine measured the total penetration and rate of penetration. The Oliver and Pharr indentation model and Hertz contact theory were used to determine the Young’s modulus, hardness and creep ratio of coconut shells. Young’s modulus determined in the polar zone was 3.52x  MPa and 1.45x  MPa in the equatorial zone. The hardness was 1.16x  MPa in the polar zone and 0.7x  MPa in the equatorial zone. The creep ratio was 16 in the polar region and 8 in the equatorial zone. Validation of the procedure and results will be done with indentation tests on a kind of wood: Azobé (Lophira alata).

Keywords: macro-indentation, coconut shell, hardness, young modulus, creep ratio, abrasives

DOI 10.13140/RG.2.1.1447.3846


[1] J.A. Banzon, J.R. Velasco: Coconut: production and utilization, Philippine Coconut Res. and Dev., pp. 417, 1982.

[2] B. Warner, Q. Derek, C. Longmore: A review of the future prospects for the world coconut industry and past research in coconut, production and product, Australian Centre for International Agricultural Research, 2007.

[3] U. Tomas, J.R. Ganiron: Sustainable Management of Waste Coconut Shells as Aggregates in Concrete Mixture, Journal of Engineering Science and Technology Review 6 (5), 7-14, 2013.

[4] N. Lesage, M. Sperandio, C. Cabassud: Study of a hybrid process: Adsorption on activated carbon/membrane bioreactor for the treatment of an industrial wastewater, Chemical Engineering and Processing: Process Intensification 10th French Congress on Chemical Engineering, Volume 47, pp. 303–307, 2005, doi:10.1016/j.cep.2007.01.021

[5] E. Njeugna, D. Ndapeu, S. Bistac, J.Y. Drean N.J. Foba, M. Fogue: Contribution to the Characterisation of the Coconut Shells (Coco Nucifera) of Cameroon, International Journal of Mechanics Structural, Volume 4, Number 1, pp.1-22, 2013.

[6] W.C. Olivier, G.M. Pharr: An improved technique for determining hardness and elastic-modulus using load and displacement sensing indentation experiments, J. Mater. Res. 7, 1564–1583, 1992.

[7] D. Tabor: Review of Physics in Technology, 1970.

[8] H. Hertz: Über die Berührung fester elastischer Körper, Journal für die reine und angewandte Mathematik 92, 156-171, 1881.

[9] Standard Test for Microhardness of material, ASTM Standard Method E 384, Annual Book of Standards 3.01, American Society for Testing and Materials, p469, 1989.

[10] C. Gauthier, A.L. Durier, C. Fond, R. Schirrer: Scratching of a coated polymer and mechanical analysis of a scratch resistance solution, Tribology International, Volume 39, pp 88–98, 2006, doi:10.1016/j.triboint.2005.04.014

[11] D. Ndapeu : Caractérisation physico-chimique et mécanique des coques de noix de coco nucifera du Cameroun, en vue de leur utilisation dans l’élaboration des matériaux abrasifs, Thèse de doctorat Ph/D de l’Université de Dschang, 2015.

[12] D.J.A. Mendoza : Détermination des propriétés mécaniques et des lois de comportement par indentation instrumentée, Thèse de Doctorat de l’Université de Lille 1, 2009.

[13] J. Breuils, L. Jacomine, H. Pelletier, P. Peyre : Identification par méthode inverse des propriétés mécaniques de surfaces grenaillées par chocs laser, 19ème Congrès Français de Mécanique, 2009.

[14] T. Chatel : Fluage et recouvrance d’empreintes et de sillons sur surface de polymère, Thèse de Doctorat de l’Université de Strasbourg, 2010.

[15] P.E. Mazeran, M. Beyaoui, M. Bigerelle, M. Guigon: Determination of mechanical properties by nanoindentation in case of viscous materials, International Journal of Materials Research, 103, 2012, doi: 10.3139/146.110687

[16] C. Philippe : Détermination des propriétés mécaniques de céramiques poreuses par essais de microindentation instrumentée sphérique, Mémoire de Thèse de l’Institut national des sciences appliquées de Lyon, 2013.

[17] T. Chatel, V. LeHouérou, H. Pelletier, C. Gauthier: Numerical analysis of the creep of the contact and recovery of the imprint on amorphous polymer surfaces. Mechanics of Time-Dependent Materials, 17(4), 581–595, 2013, doi: 10.1007/s11043-012-9205-x

[18] G.M. Pharr, W.C. Oliver, F.R. Brotzen: On the generality of the relationship among contact stiffness, contact area, and elastic modulus during indentation, Journal of Materials Research 7, pp. 613-619, 1992.

[19] W.C. Oliver, G.M. Pharr: Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology, Journal of Materials Research, Volume 19 No. 1, 2004.

[20] E. Barthel, D. Chicot, J.P. Guin, E. LeBourhis, G. Mauvoisin : L’indentation : un outil de caractérisation multi-échelle des matériaux, aSF2M Info, 2014.

[21] J. Menčík: Determination of mechanical properties by instrumented indentation. Meccanica, 42(1), 19-29, 2007.

[22] J.W.G. Van de Kuilen, H.J. Blass: Mechanical properties of azobé (Lophira alata). Holz als Roh-und Werkstoff, 63(1), 1-10, 2005.

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