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A series of experiments of dart fall (impact tests) were developed in order to quantify the capacity of absorbing energy on a set of foam materials based on polyolefin structure, prior to a fracture failure can be occurred. Foams were produced by a process of nitrogen dissolution at high pressure. Fracture strength (smax), tenacity and dynamic cushioning curves, representing the deceleration peak (G) for each sample as a function of the applied static stress, have been determined. On these curves it is possible to establish three regions associated with different physical explanations to give the optimal work zone to be used in particular conditions. The rigidity of these foams increases with the density of materials. From the developed tests it is possible to suppose that stretching of cell walls is a determining aspect in the mechanism to obtain the modulus of elasticity observed by the indentation experiments. The elasticity modules measured by indentation almost were independent of the dart diameter. These elasticity modules are lesser than those estimated by compression tests.
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¡Almanza O., Rodríguez-Pérez M. A., de Saja J. A. 2001. The microstructure of polyethylene foams produced by a nitrogen solution process. Polymer, 42, 7117-7126.
Carriazo, J. G. 2009. Introducción a la Ciencia de los Materiales (Código: 1000040)-Programa de asignatura. Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá.
Casiraghi, T., Castiglioni, G., Ronchetti, T. 1988. Fracture mechanics of polymers. Critical evaluation for linear elastic behaviour at high speed testing. J. Matter. Sci., 23, 459-466.
Gibson, L. J., Ahsby, M. F. 1988. “Cellular Solids: Structure and Properties”, Pergamon Press, Oxford, p. 217, England.
Greszczuk, L. B. 1982. In “Impact Dynamics”, edited by Greszczuk, L. B., Zukas, J. A., Nicholas, T., Swift, H. F.; Curran, D.R.; (John Wiley & Sons, New York), p. 55.
Hertz, H. 1881. On the contact of elastic solids. J. Reine Angew. Math., 92, 156-171. Translated and reprinted in English in Hertz¢s miscellaneous papers: Macmillan & Co., London, 1896.
Loveridge, P., Mills, N.J. 1991. The mechanism of the recovery of impacted high-density polyethylene foam. Cell. Polym., 10, 393-405.
Lye, S. W., Chuchom S. 1997. A neural predictive model for characterising impact cushioning curves. Engng. Applic. Artif. Intell., 10, 639-646.
Lye, S.W., Lee, S.G., Chew, B.H. 2004. Virtual design and testing of protective packaging buffers. Computers in Industry, 54, 209-221.
Marsavina, L., Sadowski, T. 2008. Dynamic fracture toughness of polyurethane foam. Polymer Testing, 27, 941–944.
Mills, N. J., Hwang, A. M. H. 1989. The multiple-impact performance of high density polyethylene foam. Cell. Polym, 9, 259-270.
Ouellet, S., Cronin, D., Worswick, M. 2006. Compressive response of polymeric foams under quasi-static, medium and high strain rate conditions. Polymer Testing, 25, 731-743.
Ozturk, U. E., Anlas, G. 2009. Energy absorption calculations in multiple compressive loading of polymeric foams. Materials and Design, 30, 15-22.
Rayleigh, L. 1906. On the production of vibration by forces of relatively long duration with the applications to the theory of collisions. Phil. Mag., 11[3], 283.
Rodríguez-Pérez, M. A., Velasco, J.I., Arencón, D., Almanza O., De Saja, J. A. 2000. Mechanical characterization of closed-cell polyolefin foams. J. Appl. Polym. Sci.,75, 156-166.
Ruiz-Herrero, J.L., Rodríguez-Pérez, M.A., de Saja, J.A. 2005. Design and construction of an instrumented falling weight impact tester to characterise polymer-based foams. Polymer Testing, 24, 641-647.
Timoshenko, S. P., Woinwsky – Krieger, S. 1984. “Theory of Plates and Shells”; McGraw-Hill: Tokyo, Japan.
Velasco, J. I., Martínez, A. B., Arencón, D., Rodríguez-Pérez, M. A., de Saja, J. A. 1999. Application of instrumented falling dart impact to the mechanical characterization of thermoplastic foams. J. Matter. Sci., 34, 431-438.
Velasco, J. I., Martínez, A. B., Arencón, D., Almanza O., Rodríguez-Pérez, M. A., De Saja, J. A. 2000. Rigidity characterization of flexible foams by falling dart rebound tests. Cell. Polym., 19,115-133.
Zotefoams Ltda. 1992. Cushioning Packaging Guide, Croydon, U. K.
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