Experimental determination of splitting in axially collapsed thick-walled fibre-reinforced composite frusta
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Mamalis, AG
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Demosthenous, GA
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Ioannidis, MB
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Manolakos, DE
(EN)
The failure mechanisms of thick-walled circular frusta, made of glass-fibre-reinforced composite material, when subjected to axial compression are reported. Depending on wall thickness and the semi-apical angle, a conical shell may fail by four distinct deformation modes: progressive crushing, splitting, mid-length failure and progressive folding. Progressive crushing was found to offer the highest energy-absorption efficiency, the two latter belonging to catastrophic deformation modes with low energy-absorbing characteristics. Splitting usually follows after a short distance of progressive crushing for specimens with semi-apical angles greater than 25 degrees, constituting a transition mode from stable collapse to catastrophic collapse, which should be avoided in the lending of crashworthy structures. The present paper deals mainly with the splitting mechanism. On the basis of experimental observations pertaining to axially collapsed relatively thick-walled composite frusta of large semi-apical angles, a criterion for transition from stable collapse to this catastrophic deformation pattern is proposed. Strain gauges were mounted on the tube wall all over its axial length at highly strained positions and useful conclusions on the mechanical response of the composite material over the critical region are drawn from the strain data obtained. (C) 1998 Elsevier Science Ltd. All rights reserved.
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