Design of a bending experiment for mechanical characterisation of pultruded rods under compression

Carbon fibre pultruded rods are used in structural applications across a wide range of industries due to their lightweight, corrosion/fatigue resistance and outstanding properties in the axial direction. While there is available literature on the mechanical characterisation of pultruded rods under tension and bending, very little has been reported about their compression response. The characterisation of the mechanical performance of pultruded rods under uniaxial direct compression is challenging due to the high sensitivity to alignment, stress concentrations in the gripping zone, and the complexity of specimen manufacturing, especially when the rods can be of small diameter (~1mm). Existing literature reports the use of the compression side of a beam under bending to test materials with high axial stiffness and strength such as carbon fibre laminates. In this work, we show the applicability of such idea on pultruded rods. We report on the design of a novel bending experiment to characterise the compression behaviour of pultruded rods, ensuring low strain gradient and consistent failure within the gauge section.