Behaviour of hollow pultruded GFRP square beams with different shear span-to-depth ratios

Aravinthan

2017

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Please cite this article as: Ferdous, W., Manalo, A., Aravinthan, T., Effect of beam orientation on the static behaviour of phenolic core sandwich composites with different shear span-to-depth ratios, Composite Structures (2017), doi: http://dx. AbstractThis study thoroughly investigated the flexural behaviour of phenolic cored sandwich beams with glass fibre composite skins in the horizontal and vertical positions. The beams have a shear span-to-depth ratio (a/d) varying between 0.5 and 12, and tested under 4-point static bending. Their failure load are then predicted theoretically. The results showed that changing the beam orientation from horizontal to vertical changes the failure mode from brittle to progressive. The sandwich beam's high bending stiffness can be efficiently utilised by placing them vertically. The a/d ratio played a major role on the load capacity and failure mode. In both orientations, the load capacity decreased with the increased of a/d. The beam failed in shear, a combined shear and bending, and bending for a/d ≤ 2, 2 < a/d < 6, and a/d ≥ 6, respectively. These failure mechanisms can be correlated to the shear-to-bending stress ratio while the failure load can be reasonably predicted using the available theoretical models.The two-way analysis of variance showed that the beam orientation is a more influential parameter than the a/d ratio. From this study, the horizontal beams are preferable for flexural dominated structures while the vertical beams are desirable for shear dominated structures.

Section: Bending and Shear Stiffnessmentioning

confidence: 99%

Effect of beam orientation on the static behaviour of phenolic core sandwich composites with different shear span-to-depth ratios

Ferdous

Aravinthan

2017

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“…On the other hand, the elastic modulus and shear modulus were determined from tests of the whole section in a previous study by the authors [31]. The burnout test conducted as per ISO 1172 standard [32] revealed that the density and the fibre volume fraction are 2050 kg/m 3 and 78% by weight, respectively.…”

Section: Experimental Program 21materials Propertiesmentioning

confidence: 99%

“…As the elastic instability of the pultruded GFRP sections in compression is governed by the local buckling [38], Muttashar et al [31] suggested to use buckling stresses, σ cr local instead of the allowable compressive stresses in equation 3. An approximate expression to determine the buckling stresses for free and rotationally restrained orthotropic plates has been proposed by Kollár [39].…”

Section: Effect Of Concrete Compressive Strengthmentioning

confidence: 99%

Flexural behaviour of multi-celled GFRP composite beams with concrete infill: Experiment and theoretical analysis

Muttashar

Karunasena

et al. 2017

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This research introduces multi-celled glass fibre reinforced polymer (GFRP) beam sections partially filled with concrete. Pultruded GFRP square tubes (125 mm x125 mm x 6.5 mm) were bonded together using epoxy adhesives to form the beams using 2 to 4 cells. Concrete with 15 and 32 MPa compressive strengths was used to fill the top cell of the beams. These beams were then tested under static four-point bending and their behaviour was compared with hollow beams. The results showed that up to 27% increase in strength was achieved by multi-celled compared to a single cell beam. The beams with concrete infill failed at 38% to 80% higher load and exhibited 10 to 22% higher stiffness than their hollow counterparts. The increase in the compressive strength of the concrete infill from 15 MPa to 32 MPa resulted in up to 14% increase in the failure load but did not enhance the flexural stiffness. Finally, the proposed prediction equation which account for the combined effect of shear and flexural stresses showed a good agreement with the experimental results for hollow cells and up to 3 cells of concrete filled beams. The bearing stress equation gave a better estimation for 4-cell filled section. KeywordsComposite beam, multi-cell beams, concrete in-fill, flexural behaviour, theoretical prediction. All Tables.pdf [Table] To view all the submission files, including those not included in the PDF, click on the manuscript title on your EVISE Homepage, then click 'Download zip file'. RESEARCH PAPER AbstractThis research introduces multi-celled glass fibre reinforced polymer (GFRP) beam sections partially filled with concrete. Pultruded GFRP square tubes (125 mm x125 mm x 6.5 mm)were bonded together using epoxy adhesives to form the beams using 2 to 4 cells. Concrete

“…The elastic modulus and shear modulus of the square pultruded GFRP sections were determined previously by Muttashar et al. [25] and are listed in Table 1. On the other hand, coupon tests were conducted to determine the compressive and tensile strength properties for the sections.…”

Section: Properties Of Gfrp Tubes and Concretementioning

confidence: 99%

Influence of infill concrete strength on the flexural behaviour of pultruded GFRP square beams

Muttashar

Karunasena

et al. 2016

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This paper presents experimental and analytical studies on the effect of the compressive strength of the concrete infill on the flexural behaviour of composite beams. Hollow pultruded Glass Fibre Reinforced Polymer (GFRP) square beams (125 mm x125 mm x 6.5 mm) filled with concrete having 10, 37 and 43.5 MPa compressive strength were tested under static four-point bending. The results indicate that filled GFRP beams failed at a load 100 to 141% higher than hollow beams and showed 25% increase in stiffness. However, the increase in concrete compressive strength from 10 to 43.5 MPa increased the ultimate load by only 19% but exhibited almost the same flexural stiffness indicating that a low strength concrete is a practical solution to fill the GFRP profiles to be used as beam applications. Moreover, the concrete infill prevented the premature buckling and web crushing of the GFRP tube. The maximum strain measured at failure is similar to the compressive strain determined from the coupon test indicating the effective utilisation of the GFRP material. Finally, Fibre Model Analysis which considered the partial confined stress -strain curve for the concrete infill gave an accurate prediction of the flexural behaviour of the concrete filled GFRP sections.