Thermal buckling of a heat-exposed, axially restrained composite column

Liu, L.; Kardomateas, G. A.; Birman, Victor; Holmes, John W.; Simitses, George J.

doi:10.1016/j.compositesa.2005.04.006

Cited by 45 publications

(19 citation statements)

References 6 publications

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“…It is not known whether the higher stiffness, operating temperature and softening temperature of basalt fibre translates into superior fire resistance when used as the reinforcement to polymer composite materials. A large body of research has been published on the fire structural resistance of E-glass reinforced composites under compressive and tensile loading [7][8][9][10][11][12][13][14][15][16][17][18][19]. Similarly, the fire resistance of carbon fibre laminates have also been studied [20,21].…”

Section: Introductionmentioning

confidence: 97%

Fire structural resistance of basalt fibre composite

Bhat

Chevali

Liu³

et al. 2015

Composites Part A: Applied Science and Manufacturing

117

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a b s t r a c tBasalt fibres are emerging as a replacement to E-glass fibres in polymer matrix composites for selected applications. In this study, the fire structural resistance of a basalt fibre composite is determined experimentally and analytically, and it is compared against an equivalent laminate reinforced with E-glass fibres. When exposed to the same radiant heat flux, the basalt fibre composite heated up more rapidly and reached higher temperatures than the glass fibre laminate due to its higher thermal emissivity. The tensile structural survivability of the basalt fibre composite was inferior to the glass fibre laminate when exposed to the same radiant heat flux. Tensile softening of both materials occurred by thermal softening and decomposition of the polymer matrix and weakening of the fibre reinforcement, which occur at similar rates. The inferior fire resistance of the basalt fibre composite is due mainly to higher emissivity, which causes it to become hotter in fire.

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Section: Introductionmentioning

confidence: 97%

Fire structural resistance of basalt fibre composite

Bhat

Chevali

Liu³

et al. 2015

Composites Part A: Applied Science and Manufacturing

117

View full text Add to dashboard Cite

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“…With this boundary condition, the axial load P would act along the neutral axis of the specimen and the stress distribution caused by the external force P will not generate a mechanical moment although the material properties distribution is not uniform along the thickness direction during the tests. However, since the temperature and material properties such as Young's modulus are non-uniform along the thickness of the specimen, a thermal moment can develop from the onset of testing [17]. The resultant moment can be expressed in the form ò A E l a l DT(y -e)dA, where e is the eccentric distance between the geometric center and the neutral center of the cross section (if we assume as an approximation isotropic behavior), A is the area of the cross section, and y is the coordinate along the thickness direction (see Figure 11).…”

mentioning

confidence: 99%

Compressive Response of Composites Under Combined Fire and Compression Loading

et al. 2009

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The thermal buckling of an axially restrained composite column that is exposed to a heat flux due to fire is studied by both analytical and experimental means. The column is exposed to fire from one-side and the resulting heat damage, the charred layer formation and non-uniform transient temperature distribution are calculated by the thermal model developed by Gibson et al. (Revue de l'Institute Francais du Petrole 50:69-74, 1995). For the thermal buckling analysis, the mechanical properties of the firedamaged (charred) region are considered negligible; the degradation of the elastic properties with temperature (especially near the glass transition temperature of the matrix) in the undamaged layer, is accounted for by using experimental data for the elastic moduli. Due to the non-uniform stiffness and the effect of the ensuing thermal moment, the structure behaves like an imperfect column, and responds by bending rather than buckling in the classical Euler (bifurcation) sense. Another important effect of the non-uniform temperature is that the neutral axis moves away from the centroid of the cross section, resulting in another moment due to eccentric loading, which would tend to bend the structure away from the fire. In order to verify the mechanical response, the compressive buckling behavior of the same material subjected to simultaneous high intensity surface heating and axial compressive loading were investigated experimentally. Fire exposure was simulated by subjecting the surface of rectangular specimens to radiant heating in a cone calorimeter. Heat flux levels of 25 kW/m 2 , 50 kW/m 2 and 75 kW/m 2 were studied. All specimens exhibited buckling and subsequent catastrophic failure, even at compressive stresses as low as 3.5 MPa under a surface heat flux of 25 kW/m 2 . Details of the experimental procedure, including modifications made to a cone calorimeter to allow simultaneous mechanical loading are presented.

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“…A thermo-structural model was developed by Asaro and colleagues [15,16] which used a simple heat conduction model and beam theory to predict the structural response of a thermally-exposed laminate. Liu et al [17] developed a model assuming a linear temperature gradient based on steady-state conduction. The structural model included thermal effects by use of a thermal moment caused by non-uniform mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

“…Mechanical properties were calculated using the predicted temperatures and material decomposition state using the model developed by Gibson et al [12]. The methodology developed by Liu et al [17] was implemented to predict the structural response with inclusion of temperature and decomposition state dependent mechanical properties. The principles used by Feih et al [13,14] to predict failure based on compressive strength were modified to predict failure.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity Analysis of a Thermo-Structural Model for Materials in Fire

Summers¹,

Lattimer²,

Case³

et al. 2011

Fire Safety Science - Proceedings of the 10th International Sym

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A new thermo-structural model was developed and validated to predict the failure of compressively loaded fiber-reinforced polymer (FRP) laminates during one-sided heating from a fire. The model consists of the best thermal and structural models in the literature integrated into a single predictive model. This includes a one-dimensional pyrolysis model to predict the thermal response of a decomposing material. Using the thermal response to calculate the mechanical properties, an integral structural model was developed considering thermally-induced bending caused by one-sided heating. The thermo-structural model predicts out-of-plane deflections and compressive failure of laminates in fire conditions. This paper also provides an improved failure model for FRP laminates exposed to fire, a first validation study on the modeling approach using intermediate-scale compression load failure tests with a one-side heat flux exposure, and a first sensitivity study of the input parameter effects on the structural response of FRP laminates. Through the sensitivity study, the out-of-plane deflection predictions exhibited little sensitivity to the thermal inputs. However, the time-to-failure predictions were significantly affected by the virgin conductivity and specific heat capacity. The structural inputs exhibited a significant impact on the out-of-plane deflection predictions. The in-plane thermal expansion, residual elastic modulus above the glass transition temperature, and vertical temperature profile significantly affected the magnitude of the out-of-plane deflection; however, only the in-plane thermal expansion and residual elastic modulus affected the failure direction. The time-to-failure prediction was only significantly affected by the residual elastic modulus. A better agreement between the predicted and observed times-to-failure was achieved by reducing the residual elastic modulus.KEYWORDS: sensitivity, thermo-structural, modeling, composites, FRP laminate. NOMENCLATURE LISTING

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Thermal buckling of a heat-exposed, axially restrained composite column

Cited by 45 publications

References 6 publications

Fire structural resistance of basalt fibre composite

Fire structural resistance of basalt fibre composite

Compressive Response of Composites Under Combined Fire and Compression Loading

Sensitivity Analysis of a Thermo-Structural Model for Materials in Fire

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