Laminate Theory Analysis of Composites under Load in Fire

This paper investigates the compression failure of carbon fiber-epoxy laminates when exposed to fire. The investigation gives insights into the softening and failure of carbon-epoxy laminates supporting compression loads in the event of aircraft fire. A thermomechanical model is presented for calculating the compression properties and failure of polymer matrix laminates under combined loading and one-sided heating by fire. The accuracy of the model to predict the failure time of carbon-epoxy laminates at different compression load levels and fire temperatures is determined with structural fire tests performed on woven carbon-epoxy panels. The model predicts a gradual increase in the failure time of the laminate with decreasing compression stress (down to 10% of the room temperature buckling load) and decreasing heat flux (or temperature) of the fire. This was confirmed by the fire tests, which showed good agreement between the calculated and measured failure times. Compression failure of the laminate usually occurred within relatively short times (less than a few minutes) by viscous softening of the polymer matrix. For long failure times, matrix decomposition was shown to influence the failure process. Parametric analysis using the model reveals that raising the glass transition temperature of the polymer matrix increases the compression failure time of laminates in fire. However, only small improvements to the failure time are achieved by raising the glass transition temperature of laminates exposed to high-temperature fires typical of postcrash aircraft accidents. = an empirical exponent of the remaining resin content fitted to experimental data to best describe the order of the relationship between polymer mass loss and residual strength Q p = decomposition energy of polymer matrix R rc T = remaining resin content T = temperature T g = chemical glass transition temperature T k = mechanical glass transition temperature t = heating time w f = final remaining mass fraction of polymer resin x = through-thickness coordinate = heating rate of laminate = laminate density c 0 = room temperature compression strength c R = residual compression strength c T = compression strength as a function of temperature x k = strength at position x k in the through-thickness direction of the laminate = rate of strength decay

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“…In recent years, research studies [4][5][6][7][8][9] have shown that the typical relationship between a mechanical property of a polymer composite and temperature under isothermal condition (that is, constant temperature throughout the material) is generally that shown in Figure 5. Since limited data exist on individual mechanical properties, such as modulus and strength, it is assumed for convenience that all mechanical properties can be fitted to the typical mechanical property versus temperature relationship shown in Figure 5.…”

Section: Analytical Modelsmentioning

confidence: 99%

“…The authors have, on the basis of previously published research on the high temperature performance of polymer composites [4,5,6,7,8,9], selected a sigmoid curve based on a hyperbolic tangent function [4,5,6] to describe the mechanical and bond property degradation of GFRP composites. In this study, was taken to be 1.0 because, based on TGA, the resins do not experience any significant amount of decomposition until 350°C and was the average of the observed values of the property at room temperature.…”

Section: Implementation In Structural Fire Modelmentioning

confidence: 99%

Mechanical Characterization of Fibre Reinforced Polymers Materials at High Temperature

Chowdhury

¹

,

Eedson

²

,

Bisby

³

et al. 2009

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/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1007/s10694-009-0116-6Fire Technology, 45, 4, pp. 1-18, 2009-12-01 Mechanical characterization of fibre reinforced polymers materials at high temperatures Chowdhury, R.; Eedson, R.; Bisby, L. A.; Green, M. F.; Bénichou, N.http://www.nrc-cnrc.gc.ca/irc M e c ha nic a l c ha ra c t e riza t ion of fibre re inforc e d polym e rs m a t e ria ls a t high t e m pe ra t ure s NRCC-50851Chowdhury, R.; Eedson, R.; Bisby, L.A.; Green, M.F.; Bénichou, N. December 2009A version of this document is published in / Une version de ce document se trouve dans:Fire Technology, 45, no. 4, pp. 1-18, DOI: 10.1007/s10694-009-0116-6 The material in this document is covered by the provisions of the Copyright Act, by Canadian laws, policies, regulations and international agreements. Such provisions serve to identify the information source and, in specific instances, to prohibit reproduction of materials without written permission. For more information visit http://laws.justice.gc.ca/en/showtdm/cs/C-42Les renseignements dans ce document sont protégés par la Loi sur le droit d'auteur, par les lois, les politiques et les règlements du Canada et des accords internationaux. Ces dispositions permettent d'identifier la source de l'information et, dans certains cas, d'interdire la copie de documents sans permission écrite. Abstract. One of the greatest impediments to using fibre reinforced polymer (FRP) composites in buildings and parking garages is their susceptibility to degradation when exposed to elevated temperatures and the limited knowledge on the thermal and mechanical properties of these composites at such temperatures. Glass FRP (GFRP) tensile coupons and single lap-splice coupons were tested in tension to study the mechanical properties under steady-state and transient thermal conditions. Tests were conducted at a range of temperatures between room temperature and +200°C. In terms of tensile strength, approximately half of the strength of the FRP was lost near the glass transition temperature of the epoxy resin matrix. However, 40% of the room temperature strength of the GFRP was still retained at 200°C. The lap-splice tests showed that the FRP-to-FRP bond strength was affected even more by high temperature exposure with 90% loss in lap-splice near the glass transition temperature. An analy...

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“…Since the stress-strain behaviour of the FRP composites at both ambient and elevated temperature was observed to be linear-elastic to failure in direct tension coupon tests conducted by the authors [12,23] Gibson et al [24] has been used to describe the high temperature degradation of the FRP's tensile strength and tensile elastic modulus . The Gibson et al model is semi-empirical and is based on a non-linear leastsquares curve fit of data from tests performed by the authors on a specific glass/epoxy FRP strengthening system at elevated temperatures [12,23].…”

Section: Mechanical Property Models At Elevated Temperaturementioning

confidence: 99%

Heat transfer and structural response modelling of FRP confined rectangular concrete columns in fire

Chowdhury

¹

,

Bisby

²

,

Green

³

et al. 2012

Construction and Building Materials

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/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10. 1016/j.conbuildmat.2010.12.064 Construction and Building Materials, 25, 12, pp. 1-28, 2011-07-01 Heat transfer and structural response modelling of FRP confined rectangular concrete columns in fire Chowdhury, E. U.; Bisby, M. F.; Green, M. F.; Bénichou, N.; Kodur, V. K. R. strengthening systems at elevated temperatures, and the perceived susceptibility of these systems to fire continues to discourage their use in some applications. To begin to address this issue for the specific case of strengthening rectangular concrete columns with FRP wraps, an experimental and analytical study has been performed. An objective of the study is to develop validated computational models that can be used to perform parametric analyses and suggest design guidelines for these types of structural members. This paper presents the development and partial verification of a computational model that can simulate the structural behaviour of a short or slender, concentrically or eccentrically loaded, unwrapped or FRP wrapped column under both ambient and fire conditions. Results of initial analytical studies, including validation of the model using test data available in the literature, are presented.

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Laminate Theory Analysis of Composites under Load in Fire

Cited by 200 publications

References 21 publications

Compression Failure of Carbon Fiber-Epoxy Laminates in Fire

Compression Failure of Carbon Fiber-Epoxy Laminates in Fire

Mechanical Characterization of Fibre Reinforced Polymers Materials at High Temperature

Heat transfer and structural response modelling of FRP confined rectangular concrete columns in fire

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