Comparative study of the quasi-static energy absorption of small-scale composite tubes with different geometrical shapes for use in sacrificial cladding structures

Abstract

This paper focuses on the quasi-static crushing characteristics and the corresponding energy absorption of nine different shapes of small-scale composite tubes. The idea is to choose suitable cross sections and geometrical shapes of the composite tubes which can yield progressive deformation and higher energy absorption; the finalized geometrical shapes will be studied further for the inner core of a sacrificial cladding structure against blast loading. All the composite tubes have been manufactured by a hand lay-up technique using E-glass fabric and polyester resin. Quasi-static axial crushing tests have been conducted to understand the deformation patterns and the corresponding load-deformation characteristics of each composite tube. The effect of dimensions (thickness to diameter ratio) on the specific energy absorption of each composite tube was studied. Finally, the quasi-static test parameters such as the peak crush load, mean crush load and the specific energy absorption of all these composite tubes were compared. From this unique study, it was found that the specific energy absorption of special geometrical shapes (hourglass type -A, hourglass type -B, conical circular type -X and conical circular type -Y) of the composite tubes is significantly higher than the standard and uniform profiles such as the square and the hexagonal cross sections.

Parametric study of crushing parameters and failure patterns of pultruded composite tubes using cohesive elements and seam: Part II – Multiple delaminations and initial geometric imperfections

“…During the experimental crushing of a composite tube, the inner and outer petals were subjected to bending inside and outside of the tube followed by circumferential delamination. The material splaying outwards flared into petals due to the phenomena of axial cracks, and the material splaying inwards showed progressive folding without any petalling [1,9,18]. As a result, a considerable amount of energy was dissipated due to the axial cracking of the outer petals and significant amount of deceleration of the impactor was provided by the inner plies.…”

Parametric study of crushing parameters and failure patterns of pultruded composite tubes using cohesive elements and seam, Part I: Central delamination and triggering modelling

“…The energy absorption characteristics of various composite structural elements have been experimentally and theoretically studied by several researchers [1][2][3][4][5][6][7]. Different tube cross sections are employed to get the maximum energy absorption with least material investment.…”

“…The consideration of the delamination approach is important to predict the energy absorption because it causes the separation of plies and loss in bending stiffness of each sub laminate. Furthermore, many experimental studies [1,3,7,[13][14][15] have proved that the occurrence of the peak load corresponds to the start of the circumferential delamination. Hence, to understand the importance of the delamination and to achieve the typical failure patterns of a brittle composite tube, a numerical parametric study is conducted in this paper with a single layer and two layers of shell elements with cohesive elements.…”

“…The importance of these triggering mechanisms and their effects on the energy absorption are studied experimentally in [1,16]. Out of the many triggering mechanisms studied, the 45° edge chamfering was used by many researchers [1,7,8,[17][18][19]. Normally, the 45° edge chamfering can be directly modelled numerically by the solid elements.…”

“…Hence, in this work the same failure criterion was adopted to assess the energy absorption behaviour of the composite tubes. Many studies [1,5,7,24] have proven that the shape of the composite structures affect the energy absorption values of those structures. Furthermore, a few studies [3,25] demonstrated that fibre orientation along the axis of the tube absorbed more energy than any other orientations.…”