Mechanical performance of marine sandwich composites subjected to flatwise compression and flexural loading: Effect of resin pins

Balıkoğlu, Fatih; Demircioğlu, TK; Yıldız, Mehmet; Arslan, Nurettin; Ataş, Akın

doi:10.1177/1099636218792671

Cited by 28 publications

(21 citation statements)

References 29 publications

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“…12). For the PF sample, the core carried the compression force alone and when the compression force reached its peak, the curve showed a large plateau region (Balıkoğlu, Demircioğlu, Yıldız, Arslan, & Ataş, 2020). However, the compression loads of the GSF samples are primarily carried by the resin grids.…”

Section: Flatwise Compression Test Resultsmentioning

confidence: 99%

Mechanical Properties Of Sandwich Composites Used For Aerofoil Shell Structures Of Wind Turbine Blade

Balıkoğlu

Demircioğlu

Işiktaş

2021

iij

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The grid-scored foams contribute significantly to the overall mechanical properties of the sandwich structures, such as aerofoil shell structure of wind turbine blades which are subjected to different loads under operating conditions. The goal of the present paper is to examine the four-point bending, flatwise and edgewise compression and in-plane shear behaviour of sandwich panels composed of composite face sheets of E-glass/ bisphenol-A epoxy resin and plain and grid-scored PVC foams. The four-point bending failure load of the grid-scored foamed sandwich beams increased by 28.1% compared to the plain foamed ones. The flatwise compression strength of samples with grid-scored foam increased by 546% compared to plain foamed samples. The resin grids contributed to an increase in the flat-wise compression stress inducing the core crushing. Under the edgewise compression load, using the grid-scored foam increased the maximum load values by only about 2.9% relative to the plain foam. The reason for this small difference can be addressed as the facings are more effective in carrying the edgewise loadings. With the use of the grid-scored foam, an increase of 38.2% was obtained in-plane shear strength compared to plain foamed sandwich beams. The resin grids improved bonding between the facings and PVC foam.

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Section: Flatwise Compression Test Resultsmentioning

confidence: 99%

Mechanical Properties Of Sandwich Composites Used For Aerofoil Shell Structures Of Wind Turbine Blade

Balıkoğlu

Demircioğlu

Işiktaş

2021

iij

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“…The pins stiffened and strengthened the PVC foam against low shear loads, while the foam core supported the pins and prevented the premature shear failure. 30 The FEA successfully captured the initial stiffness and the post yield response of the PRFS specimens. PRFS_Ø2, 4R specimens failed due to compressive upper face sheet failure under the loading points while PRFS_Ø2, 4S specimens failed by core shear failure.…”

Section: Load-displacement Curvesmentioning

confidence: 99%

“…14–17 Therefore, the influence of core modifications on the mechanical properties of sandwich structures has been investigated by a number of researchers. 18–33 Mitra 18 revealed the efficiency of introducing the semi-circular shaped grooves into the sandwich panels to improve the shear performance. It was shown that the delamination initiation load of sandwich composite columns subjected to in-plane compressive loading could be increased approximately 25% by inserting pre-manufactured shear keys in foam-core grooves.…”

Section: Introductionmentioning

confidence: 99%

Improving four-point bending performance of marine composite sandwich beams by core modification

Balıkoğlu

Arslan

Demircioğlu

et al. 2020

Journal of Composite Materials

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The aim of this study was to improve four-point bending performance of foam core sandwich composite beams by applying various core machining configurations. Sandwich composites have been manufactured using perforated and grooved foam cores by vacuum-assisted resin transfer moulding method with vinyl-ester resin system. The influence of grooves and perforations on the mechanical performance of marine sandwich composite beams was investigated under four-point bending test considering the weight gain. Bending strength and effective bending stiffness increased up to 34% and 61%, respectively, in comparison to a control beam without core modification. Analytical equations were utilised for calculating the mid-span deflection, equivalent bending stiffness and ultimate bending strength of the sandwich beams. Finite element analysis was also performed to analyse the flexural response of the specimens taking into account the combined effect of orthotropic linear elasticity of the face sheet and the non-linear behaviour of the foam core.

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“…Other examples of innovation in the design of sandwich cores include shearkeying [15], tube-reinforced foam [16], composite rods [17], polymer/resin pins [18][19][20] and hybrid divided cores [21].…”

Section: Introductionmentioning

confidence: 99%

Vertically-aligned short E-glass fibre core sandwich composite: Production and evaluation

White

Machavaram

Fernando

et al. 2021

Jnl of Sandwich Structures & Materials

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This paper reports on the production and evaluation of a new class of “Z-axis” composite sandwich panel where the core consists of a dense array of vertically-aligned, 3 mm long E-glass fibre composite “beams”. The E-glass fibre bundles were aligned using electrostatic charging. A procedure was developed to retain the orientation of the short-fibre bundles whilst they were impregnated and cured with an epoxy/amine resin system. The skins were manufactured from 4-ply carbon/epoxy prepregs with a layup sequence of (0,90)s. The out-of-plane compressive strength of these Z-axis composites was found to be 25.2 and 15.2 times greater than equivalent sandwich panels made with Nomex® and aluminium honeycomb cores respectively. Their compressive strength was found to increase in proportion to the density of the core. Buckling and fracture of the vertically-aligned Z-axis composite were the predominant failure modes observed. The shear and flexural properties of the Z-axis composites were comparable to equivalent honeycomb sandwich panels manufactured from Nomex® and aluminium honeycomb cores.

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Mechanical performance of marine sandwich composites subjected to flatwise compression and flexural loading: Effect of resin pins

Cited by 28 publications

References 29 publications

Mechanical Properties Of Sandwich Composites Used For Aerofoil Shell Structures Of Wind Turbine Blade

Mechanical Properties Of Sandwich Composites Used For Aerofoil Shell Structures Of Wind Turbine Blade

Improving four-point bending performance of marine composite sandwich beams by core modification

Vertically-aligned short E-glass fibre core sandwich composite: Production and evaluation

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