Post-Impact Mechanical Characterisation of Glass and Basalt Woven Fabric Laminates

Abstract

Two woven fabric laminates, one based on basalt fibres, the other on E-glass fibres, as a reinforcement for vinylester matrix, were compared in terms of their post-impact performance. With this aim, first the non-impacted specimens were subjected to interlaminar shear stress and flexural tests, then flexural tests were repeated on laminates impacted using a falling weight tower at three impact energies (7.5, 15 and 22.5J). Tests were monitored using acoustic emission analysis of signal distribution with load and with distance from the impact point. The results show that the materials have a similar damage tolerance to impact and also their post-impact residual properties after impact do not differ much, with a slight superiority for basalt fibre reinforced laminates. The principal difference is represented by the presence of a more extended delamination area on E-glass fibre reinforced laminates than on basalt fibre reinforced ones

Post-impact mechanical characterisation of E-glass/basalt woven fabric interply hybrid laminates

“…In particular, it can be noticed that there is a strongly variable normalised count rate in the final part of the test when the applied stress goes beyond the quasi-elastic limit. In general, it is suggested, by comparison with what observed on pure basalt or E-glass fibre laminates in [2], that whenever the growing trend of acoustic emission is preserved (such as for example is the case for VBV laminates impacted at 15 and especially 22.5 J), damage progression which produces acoustic emission takes place preferentially in one of the two laminates. In contrast, when no clear trend is observable, it is possible that both E-glass and basalt fibre laminate forming the hybrids are damaged in a comparable way (this happen e.g., in all BVB laminates, with exception of the 22.5 J impacted ones).…”

“…A previous study [2] demonstrated that non-impacted basalt fibre reinforced laminates show interlaminar shear strength and flexural properties slightly superior to those of E-glass fibre reinforced laminates. Here, in the VBV laminate, which includes the lowest number of basalt fibre layers among the three configurations, adding them does not result in an improvement of interlaminar shear strength over pure E-glass fibre reinforced laminates ( Figure 1).…”

“…It is significant, however, to assess that the composite presents a sufficient impact resistance to use it for structural components. The major mode for impact damage absorption in basalt fabrics composites appears to be fibre breakage, delamination appearing less diffuse than in E-glass fibre composites [2,6]. Also, previous study suggested that in basalt fabrics composites and hybrids, crack propagation patterns during impact may be complex, if single layers are used in an interplay layout [5].…”

“…Impact damage is characterised from the study of post-impact flexural properties assisted by acoustic emission and thermography, visualising damage using scanning electron microscope (SEM) fractographs. This is carried out along the lines of two comparative studies between configurations of glass/jute fibre hybrid laminates, performed by the same research group [11][12] and in the aforementioned study about the comparison of E-glass and basalt fibre composites [2].…”

Effective modeling strategy for drop test analysis of composite curved beam

“…Studies on composite structures in the past decades have shown significant benefits of woven-fabric composite materials in enhancing the impact resistance of composite structures. Most of the experimental and numerical impact analyses, however, have been focused on two-dimensional composite plates either with unidirectional or woven fabric materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and little efforts are made for three-dimensional curved structures. To help contribute to a better understanding of the impact behavior of three-dimensional composite structures in general, this work provides experimental and computational drop test analyses of a woven fabric Eglass/E722 8HS composite curved beam.…”