A UNIFIED APPROACH TO PROGRESSIVE CRUSHING OF FIBER-REINFORCED COMPOSITE TUBES

The main features of progressive folding and progressive crushing in tubes subjected to axial compression are summarised, with particular reference to the geometry of the folded or crushed region and the force-displacement response. A detailed account is given of the two main modes of progressive crushing, splaying and fragmentation, which occur in tubes made from fibre-reinforced composite materials. The main theme of this paper is that the crush geometry and the force-displacement response are interrelated and that the wide range of material and testing variables which affect the crushing behaviour can be accounted for on this basis. By way of example, a detailed description is given of the effect of fibre arrangement on progressive crushing in carbon fibre-epoxy unidirectional laminated tubes, woven glass cloth-epoxy tubes, filament-wound angle-ply glass fibre-polyester tubes and inplane random chopped glass fibre-polyester tubes. Transitions between splaying and fragmentation modes are identified and related to the force-displacement response. Similar transitions have been reported with other variables, such as fibre and matrix properties, dimensions and shape of tubes, speed and temperature effects, and trigger geometries. These are discussed in the context of the overall theme.