Abstract
Bend stiffeners are structures employed in the offshore oil and gas industry designed to restrict curvature of flexible lines and umbilical cables connected to floating production units. They are conically shaped and fabricated in polyurethane (PU), an elastomeric material whose properties can be largely modified by the multiplicity of resins available in the market. Therefore, detailed polyurethane characterization is important to define the properties of the materials as well as to evaluate its stability in marine environment. In this work, a bend stiffener grade polyurethane was exposed to synthetic sea water and to the weather for 6 months. The material was characterized by infrared spectroscopy, tensile and stress relaxation tests. It was found that the mechanical characteristics are affected by sea water with a drop in tensile strength when material is tested on the same day that the final ageing time is completed. Relaxation and stress-strain curve fittings were performed using hyperviscoelastic and hyperelastic models, respectively. Among several hyperelastic models used, Alexander, Polynomial and Yamashita-Kawabata were found to successfully describe the experimental behavior. The hyperviscoelasticity model was compared with hyperelastic models considering the same strain rate.
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References
API: Specification 17J, specification for unbonded flexible pipe. American Petroleum Institute (2008)
Bazán, F.A.V., Lima, E.C.P., Siqueira, M.Q., Siqueira, E.F.N., Lemos, C.A.D.: A methodology for structural analysis and optimization of riser connection joints. Appl. Ocean Res. 33, 344–365 (2011)
ASTM D1141: Standard practice for the preparation of substitute ocean water (1998)
ASTM D412: Standard test methods for vulcanized rubber and thermoplastic elastomers-tension (2006)
Patra, K., Sahu, R.K.: A visco-hyperelastic approach to modelling rate-dependent large deformation of a dielectric acrylic elastomer. Int. J. Mech. Mater. Des. 11, 79–90 (2015)
Alexander, H.: A constitutive relaxation for rubber-like materials. Int. J. Eng. Sci. 6, 549–563 (1968)
Rivlin, R.S., Saunders, D.W.: Large elastic deformations of isotropic materials VII. Experiments on the deformation of rubber. Phil. Trans. Roy. Soc Lond. A 243, 251–288 (1951)
Hart-Smith, L.J.: Elasticity parameters for finite deformations of rubber-like materials. Z. Angew. Math. Phys. (ZAMP) 17, 608–626 (1966)
Yamashita, Y., Kawabata, S.: Approximated form of the strain energy-density function of carbon-black filled rubbers for industrial applications. J. Soc. Rubber Ind. 65(9), 517–528 (1992)
Anani, Y., Alizadeh, Y.: Visco-hyperelastic constitutive law for modeling of foam’s behavior. Mater. Des. 32, 2940–2948 (2011)
Silverstein, R.M., Webster, F.X., Kiemle, D.J.: Spectrometric Identification of Organic Compounds, 7th edn. Wiley, Hoboken, NJ. (2005)
Oprea, S.: Degradation of crosslinked poly (ester-urethanes) elastomers in distilled water: influence of hard segment. J. Appl. Polymer Sci. 124, 1059–1066 (2012)
Bajsic, E.G., Rek, V., Sendijarevic, A., Sendijarevic, V., Frish, K.C.: The effect of different molecular weight of soft segments in polyurethanes on photooxidative stability. Polymer Degrad. Stabil. 52, 223–233 (1996)
Boubakri, A., Guermazi, N., Elleuch, K., Ayedi, H.F.: Study of UV-aging of thermoplastic polyurethane material. Mat. Sc. Eng. A,527, 1649–1654 (2010.A)
Davies, P., Evrard, G.: Accelerated ageing of polyurethanes for marine applications. Polymer Degrad. Stabil. 92, 1455–1464 (2007)
Drapaca, C.S., Sivaloganathan, S., Tenti, G.: Nonlinear constitutive laws in viscoelasticity. Math. Mech. Solid. 12, 475–501 (2007)
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The authors would like to thank to Finep and CNPq for financial support.
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Oliveira, G.L., Ariza, A.G., Caire, M., Costa, M.F., Vaz, M.A. (2016). Mechanical Behavior Characterization of Polyurethane Used in Bend Stiffener. In: Ralph, C., Silberstein, M., Thakre, P., Singh, R. (eds) Mechanics of Composite and Multi-functional Materials, Volume 7. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, Cham. https://doi.org/10.1007/978-3-319-21762-8_12
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DOI: https://doi.org/10.1007/978-3-319-21762-8_12
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