Abstract
The behaviour of open cell flexible polyurethane foams in energy management applications, such as automotive seating, where static and dynamic comfort are the main functional attributes, is governed by two material properties: the effective stiffness; and energy lost through hysteresis under the conditions that prevail in use. In most applications the foam is subject to combined stresses (tension, shear and compression) and in some characterization procedures, such as indentation-force-deflection and ball rebound, these conditions prevail. However to elucidate the mechanisms responsible for behaviour a simple deformation regime is normally employed, in particular, simple compression. The imposed static strains may be large (40–70%) which means in practical terms that we are dealing with a highly non-linear static and dynamic mechanical situation. This is manifest by the fact that under high intensity harmonic excitation a flexible foam-based vibration isolating system exhibits behaviour similar to that of classical chaos [1].
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References
Hilyard, N. C. and Collier, P. (1985) Response of a vibration isolator with distributed non-linear stiffness at large excitations, J. Sound Vib., 101(4), 593–7.
Mendelsohn, M. A., Black, G. R., Runk, R. H. and Minier, H. F. (1965) Dependence of physical properties on composition in a series of high load bearing Polyurethane foams. J. Appl. Polym. Sci., 9, 2715–28.
Nagy, A., Ko, W. L. and Lindholm, U. S. (1974) Mechanical behaviour of foamed materials under dynamic compression. J. Cellular Plast., May/June, 127–33.
Schwaber, D. M. and Mienecke, E. A. (1971) Energy absorption in polymeric foams. II Prediction of impact behaviour from Instron data for foams with rate dependent modulus. J. Appl. Polym. Sci., 15, 2381–93.
Kane, R. P. (1965) The fatigue of flexible urethane foam. J. Cellular Plast., Jan, 217–22.
Gibson, L. J. and Ashby, M. F. (1988) Cellular Solids: Properties and Structure, Pergamon Press, Ch. 5.
Rusch, K. C. (1969) Load-compression behaviour of flexible foams. J. Appl. Polym. Sci., 13, 2297–311.
Kreter, P. E. (1985) Polyurethane foam properties as a function of foam density. J. Cellular Plast., Sept/Oct., 306–10.
Cremer, L. and Muller, H. A. (1982) Principles and Applications of Room Acoustics, Vol. 2, Applied Science Publishers, p. 239.
Snowdon, J. C. (1968) Vibration and Shock in Damped Mechanical Systems. John Wiley, New York, Ch 2.
Struik, L. C. E. (1967) Free damped vibrations of linear viscoelastic materials. Rheologica Acta, 6(2), 119–129.
French, A. P. (1971) Vibrations and Waves, Nelson, p. 66.
Dwyer, F. J. (1976) A review of factors affecting durability characteristics of flexible urethane foams. J. Cellular Plast., March–April, 104–13.
Lee, W. M. (1985) A new approach to humid age compression set study in high resilient molded foams. J. Cellular Plast., Nov–Dec, 417–22.
Armistead, J. P., Wilkes, G. L. and Turner, R. B. (1988) Morphology of water blown flexible poly urethane foams. J. Appl. Polym. Sci., 35, 601–28.
Moreleand, J. C, Wilkes, G. L. and Turner, R. B. (1991) Segmental orientation behaviour of flexible water-blown polyurethane foams. J. Appl. Polym. Sci., 43, 801–14.
Dzierza, W. (1982) Stress-relaxation properties of segmented polyurethane rubber. J. Appl. Polym. Sci., 27, 1487–99.
Hilyard, N. C. and Lee, W. L. (1992) Unpublished data.
Jones, R. E. and Fesman, G. (1965) Air flow measurement and its relations to cell structure, physical properties and processibility for flexible urethane foams. J. Cell Plast., 1, 200–16.
Wilson, D., McIntosh, J. D. and Lambert, R. F. (1988) Forchheimer-type nonlinearities for high intensity propagation of pure tones in air-saturated porous media. J. Acoust. Soc. Am., 84(1), 350–9.
Hilyard, N. C. and Collier, P. (1987) A structural model for air flow in flexible PUR foams. Cell. Polymers, 6(6), 9–26.
Gent, A. N. and Rusch, K. C. (1966a) Viscoelastic behaviour of open cell foams. Rubb. Chem. Tech., 39, 389–96.
Gent, A. N. and Rusch, K. C. (1966b) Permeability of open cell foamed materials. J. Cell. Plast., 2, 46–51.
Collier, P. (1985) The Design and Performance of Non-linear Vibration Isolating Materials, PhD Thesis, Sheffield City Polytechnic, Sheffield, UK.
Cummings, A. and Chang, I.-J. (1987) Acoustic propagation in porous media with internal mean flow. J. Sound Vib., 114(3), 565–81.
Kay, J. M. (1963) Fluid Mechanics and Heat Transfer, Cambridge University Press.
Rusch, K. C. (1965) Dynamic Behaviour of Flexible Open-Cell Foams. PhD thesis, University of Akron, U.S.A.
Hilyard, N. C. (1982a, b). Mechanics of Cellular Plastics (Ed. N. C. Hilyard), Applied Science Publishers, London, Ch. 4, Ch. 1.
Lambert, R. F. (1982) The acoustical structure of highly porous open-cell foams. J. Acoust. Soc. Am., 72(3), 879–87.
Cunningham, A. (1987) A structural model of heat transfer through rigid polyurethane foam, in Heat and Mass Transfer (eds J. Bougard and N. H. Afgan), Hemisphere Publishing Corp., pp. 32–43.
Cavender, K. D. (1990) New dynamic flexibility test. 1, in Proceedings of the 33rd Annual Polyurethane Technical/Marketing Conference, Sept. 30–Oct. 3, 282–8.
Courtney, M. H, Charlton, L. J. and Seal, K. (1989) Influence of foam density on automobile seat performance. J. Cellular Pias., 25, 472–85.
Seefried, C. G., Whitman, R. D. and Pollart, D. F. (1974) Influence of polymer structure on high resiliency urethane foams. J. Cellular Plast., 10, 171–80.
Seefried, C. G., Whitman, R. D. and Pollart, D. F. (1974) Influence of polymer structure on high resiliency urethane foams. J. Cellular Plast., 10, 171–80.
Hilyard, N. C., Lee, W. L. and Cunningham, A. (1991) Energy dissipation in polyurethane cushion foams and its role in dynamic ride comfort, in Proceedings Cellular Polymers: International Conference. Forum Hotel. London, UK. 20th–22nd March 1991, RAPRA Technology.
Lockett, F. J., Cousins, R. R. and Dawson, D. (1981) Engineering basis for selection and use of crash padding materials. Plastics and Rubber Processing and Applications, 1(1), 25–37.
Jones, R. E., Hersch, P., Stier, G. G. and Dombrow, B. A. (1959) Measuring the resilience of flexible urethane foams. Plastics Technol., 5, 55–9.
Hartings, J. W. and Hagen, J. H. (1978) Fatigue investigations of urethane seat pads. J. Cellular Plast., March/April, 81–6.
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© 1994 Springer Science+Business Media Dordrecht
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Hilyard, N.C. (1994). Hysteresis and energy loss in flexible polyurethane foams. In: Hilyard, N.C., Cunningham, A. (eds) Low density cellular plastics. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-1256-7_8
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DOI: https://doi.org/10.1007/978-94-011-1256-7_8
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-4547-6
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