Behaviour of fibre composite sandwich structures under short and asymmetrical beam shear tests

Abstract

The behaviour of structural fibre composite sandwich beams made up of glass fibre composite skins and phenolic core material was investigated under three-point short beam and asymmetrical beam shear tests. The effect of the shear span-to-depth ratio (a/D) on the strength and failure behaviour of the composite sandwich beams was examined. The results showed that with increasing a/D ratio, the failure load of the sandwich beam is decreasing. On the contrary, the coupling effect of flexural stresses increases with increasing a/D ratio.Noticeably, the fibre composite sandwich beams tested under asymmetrical beam shear exhibited higher failure load compared to beams tested under short beam shear. Analysis showed that the shear stress in the core is more dominant than flexural stress when the a/D ratio is 1 for the sandwich beams under short beam test and 1 to 3 for the sandwich beams tested under asymmetrical beams shear test. The proposed prediction equation which accounts for the combined effect of shear and flexural stresses due to the changing a/D ratio, presented a good agreement with the experimental results, showing that it can reasonably estimate the failure load of structural fibre composite sandwich beams.

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

“…From an experimental investigation of the sandwich beams at horizontal orientation, Manalo [18] observed a transitional zone for a/d ratios between 3 and 6, where the specimens experienced both shear and bending. In the present study when a/d ≥ 6, the bending failure was observed for the specimens.…”

“…This failure mechanism needs further investigation. In many circumstances, researchers have found the differences between experimental and theoretical failure loads of sandwich beams up to 20% [19], 21% [31], 30% [37], 34% [18], and even up to 100% [7]. Therefore, further investigation is necessary to establish better theoretical models that can capture the insight into the response of the sandwich beams.…”

“…Many researchers [15][16][17] indicated that shear span-to-depth ratio has a strong influence on the failure behaviour and structural performance of the sandwich beams. Manalo [18] investigated the behaviour of phenolic-core sandwich beams in horizontal orientation with different shear span-to-depth ratios. His study found that with increase of shear span-to-depth ratio, the failure load of the sandwich beam decreases due to the increase of deflection.…”

Measurement of the Shear Properties of Extruded Polystyrene Foam by In-Plane Shear and Asymmetric Four-Point Bending Tests

“…Considering these drawbacks, alternate methods should be used to measure the shear modulus and shear strength values of XPS. The asymmetric four-point bending (AFPB) test, which is regarded as an application of the Iosipescu shear test, could help to overcome these drawbacks [21][22][23][24][25][26]. The AFPB test is more advantageous than the aforementioned shear tests in that it does not require an apparatus specially designed for the test but that for the universal four-point bending test; therefore, the test can be conducted easily and conveniently.…”

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

“…At the location of loading, the maximum bending moment and shear forces exist. Manalo [36] and Awad et al [37] highlighted that for composite beams with a shear span-to-depth ratio (a/d) less than 4.5, failure will occur due to a combined effect of shear and flexural stress. In the current study, the tested beams have an a/d = 4.2.…”