Dynamic compressive response of wrapped carbon fibre composite corrugated cores

The experimental study on the compressive response of the carbon fibre composite sandwich structures with corrugated cores is reported. The corrugated core was manufactured from unidirectional carbon fibre pre-impregnated lamina wrapped around destructible triangular prisms. Individual wrapped triangular composite cores of relative density are cut from the sandwich beams and tested under both quasi-static compression and dynamic compression at a strain rate up to 8200s-1 using an instrumented direct impact Kolsky bar experiment. Under quasi-static compressive test, as the cores were provided with no lateral confinement, the failure mechanism of the composite core was that of progressive unwrapping of cores due to matrix cracking at the joints of the core webs. Under the dynamic compressive tests, the composite cores demonstrated rate-dependent behaviour. The strain rate dependency was attributed to the suppression of the quasi-static “unwrapping” failure mechanism, and inertial stabilisation of the struts against buckling leading to an upper-bound failure mechanism of crushing of carbon fibre material within the struts

ECCO Essential Requirements for Quality Cancer Care: Primary care.

ECCO Essential Requirements for Quality Cancer Care (ERQCC) are checklists and explanations of organisation and actions that are necessary to give high-quality care to cancer patients. They are written by European experts representing all disciplines involved in cancer care. This paper concerns the integration of primary care into care for all cancers in Europe. Primary care integration

A microscale integrated approach to measure and model fibre misalignment in fibre-reinforced composite

peer-reviewedThe full text of this article will not be available in ULIR until the embargo expires on the 30/08/2021Computational micromechanics of fibre-reinforced polymers (FRPs) relies on the ability of the representative volume elements (RVEs) to take into account the different features that characterise the geometry of the material system under consideration. Fibre misalignment has been proven experimentally to have a significant effect on the mechanical properties at the macroscale, but is not currently taken into consideration in models at the individual fibre level, perhaps due to the difficulty in statistically characterising the fibre misalignment. In this work, an integrated approach is presented to measure and model fibre misalignments in FRPs. A computed tomography (CT) scan is used to identify the fibre geometry and statistically characterise the fibre misalignment angle distribution. Using a methodology recently developed by the authors, three-dimensional (3D) RVEs were generated by requiring their misalignment angle distribution to fit the empirical distribution. The methodology proposed provides a framework for the systematic numerical analysis of the influence of fibre misalignment on mechanical properties of FRPs

X-ray computed tomography study of kink bands in unidirectional composites

An experimental study on the axial compressive failure of cylindrical unidirectional (UD) carbon fibre-epoxy rods has been performed to better understand kink bands and the relevant damage mechanisms in three dimensions (3D). Post-mortem X-ray micro-computed tomography (micro-CT) imaging has shown that fibre kink bands predominantly all lie within the same plane in a cylindrical rod sample uniaxially compressed without lateral constraint. Kink bands at different stages of development are contained in the damage volume and the geometric parameters of fully developed kink bands are consistent through the damage zone, with a kink-band width ω ≈ 20–320 μm, kink-band angle β ≈ 11–40° and fibre rotation angle Φ (φ + φo) ≈ 18–52°. Fibre failure, longitudinal splitting and matrix micro-cracks within the fibre kink zone are identified by scanning electron microscopy (SEM) and X-ray micro-CT observations. The smallest radius of curvature that corresponds to maximum amount of bending of the unbroken buckled fibres was ∼280 μm (40 fibre diameters). Kink-band boundary planes and longitudinal splitting have been extracted and visualised in 3D for the first time

The origin of Henry Cort’s iron-rolling process: assessing the evidence

This paper examines the available evidence relating to the disputed origin of Henry Cort’s iron-rolling process. The principal primary sources, reproduced in the Appendix, do not support the contention that Cort acquired the process from enslaved black metalworkers at John Reeder’s foundry in Jamaica; nor that the foundry was dismantled and shipped to Portsmouth for Cort’s benefit. The sources instead suggest that ordinary and widespread ironmaking processes were in use at Reeder’s foundry; that no innovation occurred there; that the chain of events by which Cort is supposed to have heard of the foundry’s activities certainly did not occur; that Reeder’s foundry was destroyed because of the threat of a Franco-Spanish invasion force; and that no part of the foundry was removed from the immediate vicinity of the island, let alone taken to Portsmouth